February 2015 Volume XXXIII No 1

insightScientifi c Journal of MEDICAL & VISION RESEARCH FOUNDATIONS

www.sankaranethralaya.org Editor: Parthopratim Dutta Majumder insight

Scientifi c Journal of Medical & Vision Research Foundations Sankara Nethralaya – The Temple of the Eye. It was in 1976 when addressing a group of doctors, His Year: 2015 Holiness Sri Jayendra Saraswathi, the Sankaracharya of the Kanchi Kamakoti Peetam spoke of the need to create a hospital with a missionary spirit. His words marked the Issue: Vol. XXXIII | No. 1 | February 2015 | Pages 1–48 beginning of a long journey to do God’s own work. On the command of His Holiness, Dr. Sengamedu Srinivasa Badrinath, along with a group of philanthropists founded a Editor: Parthopratim Dutta Majumder charitable not-for-profi t eye hospital. Sankara Nethralaya today has grown into a super specialty institution for ophthalmic care and receives patients from all over the country and abroad. It has gained international excellence and is acclaimed for its quality care and compassion. The Sankara Nethralaya family today has Typeset at: Techset Composition India (P) Ltd., Chennai, India over 1400 individuals with one vision – to propagate the Printed at: Gnanodaya Press, Chennai, India Nethralaya philosophy; the place of our work is an Alaya and Work will be our worship, which we shall do with sincerity, ©Medical and Vision Research Foundations dedication and utmost love with a missionary spirit.

Contents

Guest Editorial: Evolution of Ophthalmic Anaesthesia 1 V Jagadeesh Basic Science: Preoperative Orbit-Globe Examination for Regional Anaesthesia 2 Prashant Oberoi Basic Science: Local Anaesthetics and Adjuvants 6 S Lakshmi Prasanna Major Review: Systemic Effects of Ophthalmic Medications 11 R Sujatha Major Review: Systemic Evaluation of Patients for Ophthalmic under Regional Anaesthesia 17 V Jagadeesh Major Review: Preoperative Instructions and Preparation of Patients Posted for Cataract Surgery 20 Sonali Raman Major Review: Choosing the Type of Anaesthesia for Cataract Surgery 24 Pradyna Senthil Kumar Tips & Tricks: Managing Awake Patients under the Drapes 28 Shobha Ravishankar Short Review: Systemic and Ophthalmic Complications Following Regional Block 32 Sujatha Vittal Clinical Practice: Control of Intraocular Pressure for Insertion of Intraocular Lens 37 VV Jaichandran Emergencies: Peri-operative Management of Medical Emergencies 41 R Kannan Tips & Tricks: Management of Difficult Patients under Local Anaesthesia 46 B Manonmani

Inquiries or comments may be mailed to the editor at [email protected] Guest editorial Evolution of Ophthalmic Anaesthesia

V Jagadeesh

Director, Department of The history of anaesthesia The role of anaesthesiologists in providing local Anaesthesiology, Sankara for dates back anaesthesia for intraocular surgery has changed Nethralaya, 2,500 years. Sushruta, the over the past two decades. In 1987, Ophthalmic President, Ophthalmic Forum of fi fi Indian Society of ancient Indian surgeon rst Anaesthesia Society (OAS) held its rstmeetinthe Anaesthesiologists (OFISA), described couching—the de- USA, then in the year 1998 British OAS was Chennai, India pression of the cataract into formed in the UK. In 2009, Ophthalmic Forum of the vitreous—around 600 BC. Indian Society of Anaesthesiologists (OFISA), The inhabitants of Peru knew that chewing on coca affiliated to Indian Society of Anaesthesiologists Correspondence to: leaves caused a numbing of the mucous membrane (ISA) was started. It has now more than 250 V. Jagadeesh, members registered in it, including both Director, Department of in the mouth and this lead to use of cocaine as a Anaesthesiology, Sankara topical anaesthetic. Thus, using cocaine as topical Ophthalmologists and Anaesthesiologists not only Nethralaya, anaesthesia drops the first eye operation was done from India but all over the globe. The main aim of Chennai, India in 1884, by Carl Koller.1 In the same year, Herman this forum is to ensure high quality anaesthesia Email: [email protected] Knapp used cocaine for retrobulbar injection and care is provided to patients undergoing cataract and performed enucleation. Since that time, various other ophthalmic surgical procedures. The society local anaesthetic techniques have been developed holds 2-day meetings every 2 years where matter of and refined, including both akinetic (retrobulbar, importance to the field, new research and education peribulbar and sub-tenon’s),2–5 and non-akinetic are discussed. Apart from these, World Congress of technique (subconjunctival, deep fornix and Ophthalmic Anaesthesia (WCOA) which was started topical anaesthesia).6-8 With the advent of clear in the year 2004 in the UK meets once in 4 years. corneal phacoemulsification combined with fold- The associations and meetings of such kind able intraocular lenses, in 1992 topical anaesthesia provide a common platform for anaesthesiologists, got its resurgence as a safe and easy way achieving ophthalmologists and clinicians practicing oph- ocular anaesthesia. thalmic anaesthesia to share their experiences Topical anaesthesia has its own limitations. to promote a high standard of patient care and to Apart from surgical skill, the patient should be update themselves with the latest development in cooperative enough for successful completion of the field of ophthalmic anaesthesia. eye surgery under topical anaesthesia. For vitreo- retinal and corneal topical anaesthesia would not be appropriate. A recent study suggests that patients also prefer an akinetic regional oph- References thalmic block.9 Hence, akinetic needle technique 1. Moses R. Adler‘s Physiology of the Eye (7th edition). St. Loius is still being practiced in ophthalmic anaesthesia. Missouri: C.V.Moses, 1981, 336. Of late, anaesthesiologists have become increas- 2. Atkinson WS. Observations on anesthesia for ocular surgery. Trans Am Acad Ophthalmol Otolaryngol 1956;60:377. ingly involved in performing these regional 3. Davis DB II, Mandel MR. Posterior peribulbar anesthesia: an orbital blocks. alternative to retrobulbar anesthesia. J Cat Refract Surg Most cataract surgery are performed on elderly 1986;12:182–4. patients, with correspondingly more systemic 4. Hansen EA, Mein CE, Mazzoli R. Ocular anesthesia for cataract co-morbidities, that might put them at increased risk surgery: a direct sub-Tenon’s approach. Ophthalmic Surg of adverse medical events during and after surgery. 1990;21:696–9. Hence, pre-operative identification of medical 5. Mein CE, Woodcock MG. Local anesthesia for vitreoretinal surgery. Retina 1990;10:47–9. comorbidity is considered important for determining 6. Anderson CJ. Subconjunctival anesthesia in cataract surgery. risk and patient management. The anaesthesiolo- J Cataract Refract Surg 1995;21:103–5. gists helps to identity such underlying conditions in 7. Rosenthal KJ. Rosenthal deep topical, fornix, applied, them, discusses with the surgeons and the patients pressurized, "Nerve Block" anesthesia. Ophthalmol Clin North Am the risks benefit ratio associated with each type of 1998;11:137–43. anaesthesia and decides about the safe mode of 8. Assia EI, Pras E, Yehezkel M, et al. Topical anesthesia using lidocaine gel for cataract surgery. J Cataract Refract Surg anaesthesia to be used in them. Anaesthesia for eye 1999;25:635–9. surgery has its own implications and these would be 9. Friedman DS, Reeves SW, Bass EB, Lubomski LH, Fleisher LA, better understood by anaesthesiologists practicing Schein OD. Patient preferences for anaesthesia management ophthalmic anaesthesia. during cataract surgery. Br J Ophthalmol 2004;88:333–5.

How to cite this article Jagadeesh V. Evolution of Ophthalmic Anaesthesia, Sci J Med & Vis Res Foun 2015;XXXIII:1.

Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | 1 Basic science Preoperative Orbit–Globe Examination for Regional Anaesthesia

Prashant Oberoi

Department of Oculoplasty, Introduction Muscles Sankara Nethralaya, Local anaesthesia for ophthalmic surgery was first The extraocular muscles arise from the orbital Chennai, India used in 1884 by Austrian ophthalmologist, Karl apex in the form of the annulus of Zinn. The con- Koller, when he instilled cocaine into the conjunc- nective tissue septae connect the recti to form a 1 fi Correspondence to: tival cul de sac. Though now-a-days topical cone which is de cient posteriorly. The sensory Prashant Oberoi, anaesthesia and sub-tenon’s block are gaining nerves supplying the globe pass within the cone, Department of Oculoplasty, popularity, still there remains a place for regional as do cranial nerves III and VI.4 Sankara Nethralaya, anaesthesia. Of these, retrobulbar block is rapidly Chennai, India getting obsolete due to higher incidence of retro- Nerves Email: [email protected] bulbar haemorrhage, central retinal artery occlu- The optic nerve inserts in the medial aspect of the sion, optic nerve injury, globe perforation and globe and travels medially in the orbit to the optic intradural injection.2,3 With the peribulbar block foramen. In this position, it may be vulnerable to the complications is said to occur with lesser damage from deep medial injections. chances but still reported in literatures. These The sensory supply of the globe is via the long complications are said to occur as the rigid and short ciliary nerves, which are branches of the needles have to negotiate a curved globe which is nasociliary nerve, itself a branch of the ophthal- housed in a pyramidal shaped bony space, the mic division of the trigeminal nerve. It enters the orbit. The two shapes are dissimilar and even in orbit via the superior orbital fissure and enters the health their dimensions can be unpredictable and fibrotendinous ring. The motor supply of the become more so in disease. The knowledge of extraocular muscles is via the oculomotor (III), spatial relationship of orbit, globe, needle and the trochlear (IV) and abducens (VI) nerves.4 injectate have an important bearing on the safety 4 of the orbital blocks. Hence, in this chapter, the Blood vessels author summarizes the information related to The structures within the orbit receive their blood anatomy of globe, orbit and their relationship, size supply from the ophthalmic artery, which enters and type of the needle to be used for a safe the orbit via the optic canal within the dural conduct of regional eye blocks in patients with sheath of the optic nerve. The central artery of the normal and abnormal globe. retina is one of the smallest branches and runs within the dural sheath of the optic nerve. Orbital anatomy Venous drainage of the orbital structures is via Orbit the superior and inferior ophthalmic veins. The The orbit is a bony pyramid with its apex pointing superior ophthalmic vein passes through the towards the middle cranial fossa. The orbital rim superior orbital fissure and drains into the facial overhangs the structures within to provide protec- vein. The inferior ophthalmic vein passes through tion. The distance from orbital rim to optic the inferior orbital fissure and connects with foramen is 42–54 mm in adults. The apex of the either the superior orbital vein or the cavernous orbit is crowded with large number of nerves and sinus. vessels, thus increasing chances of injury the The blood vessels congregate at the orbital those structures should a needle penetrate to that apex. The infero-temporal and medial parts of the depth.1 orbits are relatively avascular while the superona- sal part is vascular.4 Globe The eyeball is situated in the anterior part of the Orbit Vs Globe orbital cavity closer to the roof than the floor and The volume of an average orbit is 30 ml and that nearer the lateral than the medial wall. The pos- of the average globe is ∼7 ml. This volume may ition of the globe in relation to the orbital differ depending on the size of the globe and in opening varies in normal individuals and with large myopic eyes it can be as much as 20 ml. The (e.g. tumours or thyroid disease). growth of the orbit levels off after puberty while Highly myopic eyes may develop staphylomata the globe may continue to grow. This makes when the posterior globe is enlarged with thinning internal spaces rather limited. The axes of globe of the . Eyes with posterior staphylomata are and that of orbit do not correspond with each more susceptible to needle trauma.1 other.

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Normally, the equator of the globe is at or Check for axial length of the eye slightly anterior to the lateral orbital rim and the Axially long myopic globe grows not only in spatial relationship between them is assessed by length but also in height. The width however does measuring the distance the globe (top of the not increase as much. The globe therefore tends to ) extends over the infraorbital rim and this encroach more onto the superior and the posterior distance is generally about 8 mm.5 orbital spaces. The increase in axial length is usually accompanied by stretching and thinning of sclera which in turn leads to out-pouching (sta- Forward set globe phyloma) of the entire globe wall. The incidence The globe extends quite forwardly over the infra- of staphyloma increases from ∼15% of eyes with orbital rim (>8 mm) and associated eye lids will be an axial length 27–29 mm to ∼60% with an axial lax with wide palpebral fissure and high brows. length >31 mm. The staphylomas occur at the Here, the structures in the apex of the orbit are posterior pole or posteroinferior aspect of the vulnerable to get injured with needle blocks. globe. Block techniques employing the lateral, inferolateral or superior approaches are therefore Deep set globe dangerous. A careful single medial extraconal Enophthalmic globes are deep set. The arching approach is considered to be safer as there are no bony ridges of orbital opening make the insertion staphylomas at the medial aspect.7 The axial of needle for akinetic blocks difficult. In this con- length and the presence and location of staphy- dition, there is high chance for the needle to come loma can be known from B-scan echography, in contact with the globe. Associated eyelids will which is usually done, before cataract surgery, for be short and tight. From the point of insertion, at diopter power calculation. the inferolateral quadrant, the needle must not be The other things to look into during examin- angulated more than 100 elevation from the trans- ation are congenital abnormalities such as verse plane. buphthalmos where the eye is very large and fragile. Thyroid orbitopathy is another common Preoperative examination and considerations situation where anatomy of the globe, the extrao- cular muscles and supporting orbital structures is Medical assessment Although a full clinical examination is not neces- distorted. Even small volumes of local anaesthetics sary, an assessment of general health with evalu- in these patients may cause subluxation of the ation of concurrent medical conditions should be globe. Presence of space occupying lesions of globe or other orbital structures are also cause for done. In addition, patient characteristics such as concern. External abnormal features such as claustrophobia, panic attacks, lumbar spine pro- obscure medial canthus, blepharospasm and ptery- blems and obesity (can affect positioning), and gium may also make safe needle passage difficult. communication problems should be looked for prior to surgery.6 Other possible relative contraindications to needle blocks would include one-eyed patients as well as patients with high intraocular pressures, Ocular examination where there is a possibility to further increase Importance of previous eye surgery: Elements of intraocular pressure due to volume of local anaes- ophthalmic evaluation which are important for a thetic injected.6 regional block should begin with appropriate history from the patients. Patients having under- gone previous vitreoretinal surgeries like encirc- Orbital and adnexal examination ling sclera bands may alter the anatomy of the Patients with a narrow palpebral fissure or an epi- globe sufficiently to create an hour glass shape canthal skin fold covering the medial canthus thus increasing the risk of the inadvertent needle (when planning a medial peribulbar block) will puncture. In addition, scleral explants may also make needle placement difficult. cause physical obstruction to the needle advance- The space between the orbit and the globe in ment and prevent adequate spread of the local the inferotemporal quadrant may be assessed by anaesthetic due to local scarring. placing a finger between the two at the desired Patients with history of surgery for choroidal site of needle entry (finger index). If the space is melanoma may have very thin sclera coats and inadequate, peribulbar block may be difficult and comprise a contraindication for peribulbar blocks. an alternative means of anaesthesia may be considered. Check for gaze Patients with enophthalmos are more suscep- Patients with nystagmus or a restrictive squint tible to globe trauma by needle, when blocking with the eye fixed in a particular gaze make from an inferotemporal approach.6 needle placement difficult during peribulbar In patients with shallow orbits, there is a blocks. greater chance of penetration of the globe or the

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optic nerve sheath and as such, 3.5 cm needles should be avoided in such cases.8 In patients having proptosis with an anterior displacement of the globe, injection of local anaesthetic is expected to have a higher risk of complications due to an existing high intraorbital pressure (Figure 1). Clarke and Kozeis9 have reported a case of globe luxation in a patient of thyroid orbitopathy following peribulbar block. Hence, in such cases general anaesthesia may be a better modality (Figure 2). Figure 1: Patient with proptosis of the left eye Patients with narrow palpebral fissures and showing anteriorly displaced left globe relative enophthalmic eyes may also pose a difficulty to to right. transconjunctival peribulbar blocks and a transcu- taneous route may be planned in such cases (Figure 3).8

Considerations of injection technique Needle length and size Traditionally 3.8 cm needles were used for needle blocks. However, they have been shown to have a high risk of impaling the optic nerve. Shorter 2.5 cm needles are recommended now for peribul- bar blocks although several authors have reported using 2.0 as well as 1.5 cm needles successfully Figure 2: Patient of thyroid related orbitopathy with a low complication rate. showing bilateral proptosis and soft tissue Recommended needle size is 25 G or less with signs. some authors using 30 G as well.8

Sharp Vs blunt tipped needle Traditional teaching favoured blunt tipped needle with the supposed advantages that the intraocular structures like blood vessels and nerves are pushed aside rather than traumatized and tissue planes like piercing a septae can be appreciated with it. Blunt tipped, as opposed to steep bevel cutting needles, have been shown to require more force to penetrate the globe, but translation of this into a reduction in globe perforation has not been demonstrated.10 The sharp narrow-gauge needles (25–31 gauges) reduce the discomfort on inser- tion10 at the expense of a reduced tactile feedback Figure 3: Patient with bilateral enophthalmos with a theoretically higher risk of failing to recog- with resultant deep set eyes. nize a globe perforation.

Placement of needle the junction of inferior and lateral orbital walls. The classic site of insertion of needle at the junc- At this extreme corner, it is easier to stay far away tion of lateral one-thirds and medial two-thirds from the globe and would prevent any needle along the inferior orbital rim is no more recom- injury to the inferior rectus muscle or its neuro- mended. The reasons cited are: the needle being vascular bundle. nearer to the globe, inferior rectus muscle and Medial peribulbar block is usually performed to also closer to the neurovascular bundle supplying supplement inferotemporal peribulbar injection, the inferior oblique. Several cases of diplopia particularly when akinesia is not adequate. A 25G owing to iatrogenic needle injury to inferior rectus or 26G needle is inserted in the blind pit between and oblique muscles following needle entering at the caruncle and the medial canthus to a depth of – 8 this site have been reported in literature.11,12 1.5 2.0 cm. In the modern peribulbar block, 23 G, 25 mm long needle, with bevel facing the globe, is Volume of local anaesthetic agent inserted through the skin in the inferotemporal Between 5 and 10 ml of local anaesthetic agent is quadrant as far laterally as possible, just above required for preibulbar blocks with a short needle

4 Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | Basic science as described. When supplementing with a medial References peribulbar block, no more than 3–5 ml should be 1. Parness G, Underhill S. Regional anaesthesia for intraocular injected.8 surgery. Contin Educ Anaesth Crit Care Pain 2005;(3):93–7. 2. Kumar CM, Dowd TC. Complications of ophthalmic regional blocks: their treatment and prevention. Ophthalmologica – Transcutaneous Vs transconjunctival route 2006;220:73 82. Transconjunctival route is preferable since the 3. Kumar CM. Orbital regional anesthesia: complications and their prevention. Indian J Opthalmol 2006;54:77–84. conjunctival cul de sac can be anaesthetized by 4. Johnson RW. Anatomy for ophthalmic anaesthesia. Br J topical anaesthetic agents prior to injection and it Anaesth 1995;75:80–7. also avoids bruising of the skin, seen at times 5. Leaming DV. Practice styles and preferences of ASRC with transcutaneous injection.8 However, as men- members-2003 survey. J Cataract Refract Surg tioned above Transcutaneous route should be used 2004;80:892–900. in patients with deep set eyes or short palpebral 6. Gordon HL. Preoperative assessment in ophthalmic regional anaesthesia. Contin Educ Anaesth Crit Care Pain 2006;6 fissures. (5):203–6. 7. Vohra SB, Good PA. Altered globe dimensions of axial Summary as risk factors for penetrating ocular injury during peribulbar anaesthesia. Br J Anaesth 2000;85:242–5. The various regional anaesthesia techniques avail- 8. Kumar CM. Needle-based blocks for the 21st century able are generally safe but although rare, serious . Acta Ophthalmol 2011;89:5–9. sight- and life-threatening complications have 9. Clarke PM, Kozeis M. A complication of peribulbar block in a reported to occur. Currently, there is no absolutely patient with exophthalmos. Br J Anaesth 1998;81:615. safe ophthalmic regional block. The choice of the 10. Grizzard WS, Kirk NM, Pavan PR, Antworth MV, Hammer ME, technique of block must be based on the orbit and Roseman RL. Perforating ocular injuries caused by anesthesia personnel. Ophthalmology 1991;98:1011–6. globe relationship, which varies from one individual 11. Kumar CM, Dodds C. Ophthalmic regional blocks: review to another. Hence, it is very important for an oph- article. Ann Acad Med Singapore 2006;35:158–67. thalmic care provider to have a thorough knowledge 12. Franz Schimek, Manfred Fahle. Techniques of facial nerve about these before administration of block in the eye. block. Br J Ophthalmol 1995;79:166–73.

How to cite this article Oberoi P. Preoperative Orbit–Globe Examination for Regional Anaesthesia, Sci J Med & Vis Res Foun 2015;XXXIII:2–5.

Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | 5 Basic science Local Anaesthetics and Adjuvants

S Lakshmi Prasanna

Consultant Anaesthesiologist, Introduction Unlike the ester group of drugs all amide LAs Sankara Nethralaya, The development of ‘Procaine’ and the introduc- contain ‘i’ in their generic name before the Chennai, India tion of ‘Retrobulbar’ injection by Atkinson1 are ‘-caine’. the two most important events that brought a new Esters are relatively unstable in solution and Correspondence to: life to the field of ophthalmic local anaesthesia. are rapidly hydrolysed in the body by plasma cho- S Lakshmi Prasanna, Local anaesthetic (LA) agents and injection linesterase. One of the main breakdown products Consultant Anaesthesiologist, methods have since been refined and LA techni- is para-amino benzoate (PABA) which is respon- Sankara Nethralaya, ques are increasingly popular for ophthalmic sible for allergic and hypersensitivity reactions Chennai, India surgery. Despite improvements, still potential local that has been reported with this group of drugs.5 Email:[email protected] – and systemic complications2 4 have been reported In contrast, amides are relatively stable in solu- following these procedures. To reduce such risks, tion, are slowly metabolized by hepatic amidases it is very important for an ophthalmic care pro- and hypersensitivity reactions to amide LAs are vider to have a thorough understanding of the extremely rare. In current clinical practices, ester chemistry of various LA agents, their mechanism group have largely been superseded by amide of action, indications for use, contraindications group of LA agents. and last but not the least the adverse effects reported to occur following their usage. In this LAs as isomers chapter, the above issues will be dealt in detail. LAs may also be considered in terms of their stereoisomerism. This term describes the existence of molecules with the same molecular and struc- Basic chemical structure of LA molecule tural formula, but different spatial orientation It consists of mainly three parts around a particular atom, the chiral centre. This is 1Alipophilic aromatic group, usually an unsat- like the right and left foot being mirror images of urated benzene ring. each other. Stereoisomerism occurs in the case of bupivacaine which has two stereoisomers, known 2 Hydrophilic group: a tertiary or quaternary as R and S forms, and also in the case of prilo- amine derivative with proton acceptor caine. The combination of equal amounts of the 3 Intermediate bond: a hydrocarbon connecting two stereoisomers of a particular drug is known as chain, either an ester (–CO–) or amide (–HNC–) a racemic mixture. linkage. The intermediate bond determines the classification of LA into two main groups: Why might this isomerism be important? ester and amide. The different arrangements of the R and S forms of bupivacaine are thought to be associated with differences in potency and side-effect profile. This is easy to understand if you were to try and put your right foot in your left shoe—it does not work as well and causes side-effects (pain)! This is the reason why more drugs are being prepared as a single stereoisomer such as levobupivacaine. In contrast, amethocaine (an ester) and lidocaine are achiral, i.e. they have no stereoisomers.

ESTERS AMIDES Physiologic activity of LAs are functions of the following: Benzocaine Bupivacaine Chloroprocaine Lignocaine • Lipid solubility Cocaine Articaine • Diffusibility Proparacaine Dibucaine • fi Tetracaine Mepivacaine Af nity for protein binding Prilocaine • Per cent ionization at physiological pH Ropivacaine • Vasodilating properties.

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Lipid solubility Vasodilating properties Potency is directly related to lipid solubility, All LAs, with the exception of cocaine, are vasodi- because 90% of the nerve cell membrane com- lators. Vasodilatation occurs via direct relaxation prises lipid. Increased lipid solubility leads to of peripheral arteriolar smooth muscle fibres. faster nerve penetration and blockade of sodium Greater vasodilator activity of an LA leads to channels. faster absorption and, thus, shorter duration of action. Diffusibility

Diffusibility of the LA through tissue other than K fl LA Lipid p a Protein Speed of Duration nerve tissue also in uences the speed of onset of solubility binding onset of action action. Lignocaine 2.9 7.7 65 Rapid Medium Bupivacaine 8.2 8.1 96 Slow Long Protein binding Ropivacaine 8 8.1 93 Slow Long Protein binding is related to the duration of action. The more firmly the LA binds to the protein of the sodium channel, the longer the dur- Mode of action ation of action. It is possible for an LA agent to interfere with the excitation process in a nerve ending in one or Percent ionization at physiological pH more way: LAs are weak bases and contain a higher ratio of 1 Altering the basic resting potential of the ionized (cationic) water soluble form compared nerve membrane. with non-ionized, un-charged lipid soluble form. The measurement pKa expresses the relationship 2 Altering the threshold potential (firing between the non-ionized and ionized concentra- potential) tions. Specifically, pKa is the pH at which the 3 ↓ the rate of depolarization. ionized and non-ionized forms of the local anaes- thetic are equal. It is only the non-ionized form of 4 Prolonging the rate of repolarization. the drug that diffuses across the lipid membrane of the nerve to produce the conduction block. Hence, increased concentration of non-ionized Mechanism of action form will speed up the onset of action. In general, • Blocks the sodium channel LAs with pKa values approximating to physio- • Wide ranging effects on the nervous system logical pH (7.4) have a higher concentration of non-ionized base form resulting in a faster onset. • LAs blocks the channel from the intracellular On the other hand, LA with a pKa value far from side physiological pH will have more ionized form • Must enter the neuron to work slowing the onset time of action. This explains the fact that lignocaine has a faster onset of action • increased lipophilicity is associated with compared with bupivacaine as their pKa values increased potency are 7.8 and 8.1, respectively. • Increased un-ionized fraction increases Inside the cell, the non-ionized and ionized potency forms equilibrate. The ionized form of the LA - The un-ionized molecule crosses the binds with the sodium channel. Once ‘bound’ to cell membrane the sodium channel, impulses are not propagated along the nerve. - Adding bicarbonate increases the un Alternatively, adding sodium bicarbonate to ionized fraction commercial preparations of LA solution increase the amount of non-ionized form which will Dissociation of LA molecules hasten the onset. LAs are available as salts. In solution, it exists as: One millilitre of 8.4% sodium bicarbonate RNH+ ↔ RN + H+ should be added to each 10 ml of lignocaine or The RN is the base form and RNH+ is the cat- mepivacaine and 0.1 ml of 8.4% of sodium bicar- ionic form of the drug. bonate should be added to each 10 ml of The relative proportion of each ionic form bupivacaine.6 varies with pH, Increasing the volume of sodium bicarbonate, At pH value closer to physiological pH: as mentioned above, may lead to precipitation. In RNH+ >RN+H+ peribulbar anaesthesia, addition of sodium bicar- At pH value away from physiological pH: bonate to LA solution is known to improve the RNH+

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The percentage of drug existing in each form poor liver function like hepatitis or cirrhosis, bio- can be calculated by the transformation does not occur at a normal rate Henderson–Hasselbalch equation: and thus toxicity increases.

base Log ¼ pH pKa Excretion acid Kidneys are primary excretory organs for both ester and amide types of LA and their metabolites. The two factors involved in the action of LA A percentage of given LA is excreted unchanged. are: Patients with significant renal impairment are • diffusion of the drug through the nerve sheath unable to eliminate the drug, leading to increased blood level and subsequent toxicity. • binding at the receptor site The diffusion of the drug is brought about by LAs of importance to Ophthalmology the base or the RN form of the drug and the RNH+ Proparacaine or the cationic form of the drug binds to the Proparacaine Hydrochloride Ophthalmic Solution receptor site. USP, 0.5% is a topical anaesthetic prepared as a sterile aqueous ophthalmic solution. Pharmacokinetics Proparacaine 0.5% ophthalmic solution Absorption Composition When injected into the soft tissues all LA cause Proparacaine hydrochloride U.S.P. 0.5% vasodilatation except cocaine. Procaine is a potent Chlorbutol (as preservative) I.P 0.5% vasodilator. Aqueous base q.s The absorption of LA depends upon Proparacaine is a rapid acting LA suitable for ophthalmic use. With a single drop, the onset of 1 Route of administration anaesthesia usually begins within 30 s and persists 2 Vasoconstrictor for 15 min or longer. 3 Site of injection Indications 4 Quantity of the drug 1 Measurement of intraocular pressure (tonometry) 5 Type and size of nerve 2 Removal of corneal and conjunctival foreign body 6 Potency of drug 3 Removal of sutures from the cornea

Distribution 4 Conjunctival scraping in diagnosis fl The blood level of LA is in uenced by the follow- 5 Gonioscopy ing factors: 6 Laser procedures 1 Rate at which the drug is absorbed into CVS 7 To augment the anaesthetic effect of local 2 Rate of distribution from the vascular compo- anaesthesia nent to tissues 3 Elimination of drug through metabolic and Contraindications excretory pathways. 1 Patients with known hypersensitivity to any component of the solution. Metabolism (Biotransformation) 2 Presence of a penetrating injury in the eye. Ester LA’s are hydrolysed in plasma by the enzyme pseudo-cholinesterase. More allergic reac- tions to ester linked LA is due to para-amino NOT FOR INJECTION: FOR TOPICAL benzoic acid (PABA) which is a metabolite of OPHTHALMIC USE ONLY hydrolysis of the drug. 1 out of 2800 persons has Prolonged use of a topical ocular anaesthetic may fi atypical pseudocholinesterase.8.9 In these patients produce permanent corneal opaci cation with administration of ester linked anaesthetics may accompanying loss of vision. give rise to toxicity. Adverse reactions Amide LA undergoes biotransformation in liver. Their metabolism is much more complex as 1 Little irritation, stinging or sometimes burning compared to ester linked agents. More than 70% sensations of these drugs metabolized in liver in normal 2 Conjunctival redness function. In patients with low hepatic blood flow like in patients with congestive heart failure or 3 Lacrimation

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4 Increased winking Onset of action: 2–4 min. Duration: 4–8h. 5 Rarely, a severe, immediate-type, apparently Elimination half life: 14 min to 2 h. hyperallergic corneal reaction may occur which includes acute, intense and diffuse epi- thelial keratitis; a gray, ground-glass appear- Adjuvants ance; sloughing of large areas of necrotic Vasoconstrictors epithelium; corneal filaments and, sometimes, Addition of vasoconstrictors (epinephrine and iritis with descemetitis10 felypressin) decreases the absorption of LA into the plasma and it tends to increase the duration of 6 Softening and erosion of the corneal epithe- action of the drug and minimizes bleeding occur- lium and conjunctival congestion and haemor- ring from small vessels. Hence, it is mainly used rhage have been reported10 for oculoplastic surgical procedures. Epinephrine at a dilution of 1:200,000 has no systemic 7 Allergic contact dermatitis with drying and effects.12 It is important to remember that it may fissuring of the fingertips has been reported11 cause vasoconstriction of the ophthalmic artery, Dosage for instillation of Proparacaine drops compromising the retinal circulation. For cataract extraction The use of epinephrine-containing solutions Instill 1 drop every 5–10 min for five to seven should also be avoided in elderly patients suffer- doses. ing from cerebrovascular and cardiovascular dis- Removal of sutures eases.12 Phacoemulsification cataract extraction is Instill one or two drops 2 or 3 min before usually of short duration; hence, the duration of removal of stitches. block achieved by lignocaine without epinephrine Removal of foreign bodies usually suffices. Instill one or two drops prior to operating. Tonometry Hyaluronidase Instill one or two drops immediately before Hyaluronidase is an enzyme, which reversibly measurement. liquefies the interstitial barrier between cells by depolymerisation of hyaluronic acid to a tetrasac- Lignocaine Hydrochloride charide, thereby enhancing the diffusion of mole- Belongs to amide group. cules through tissue planes.13 It is available as a In ophthalmic practice powder readily soluble in LA solution. Hyaluronidase has been shown to improve the • 2% lignocaine solution is used for administer- effectiveness and the quality of needle as well as ing regional ophthalmic blocks, sub-Tenon’s block14,15 but its use remains contro- • 2% lignocaine gel is used as a topical agent, versial.16 The amount of hyaluronidase used in published studies varies from 5 to150 IU/mL. The • 1% intracameral lignocaine, UK data sheet17 limits the concentration to 15 IU/ • lignocaine with adrenaline is used mostly in mL. Orbital swelling due to rare allergic reac- occuloplasty cases. tions18 or excessive doses of hyaluronidase-54 and orbital pseudotumour19 has been reported. Dose: 3–5 mg/kg without adrenaline. Excellent blocks can be achieved without hyaluro- 5–7 mg/kg with adrenaline. 20 nidase but there are reports of muscle dysfunc- 2% lignocaine solution contains 20 mg per ml 21 tion when it is not used during needle block. Onset of Action: 45–90 s. Duration: 45 min to 1 h. Elimination half life: 90–120 min. References 1. Feibel RM. Current concepts in retrobulbar anesthesia. Survey of Ophthalmol 1985;30(2):102–10. Bupivacaine 2. Hamilton RC. Complications of ophthalmic anesthesia. Available as 0.5% solution. Ophthalmol Clin North Am 1998;11:99–114. Dose: 2–3 mg/kg. 3. Troll GF. Regional ophthalmic anesthesia: safe techniques and – 0.5% bupivacaine solution contains 5 mg per ml avoidance of complications. J Clin Anesth 1995;7:163 72. – 4. Rubin AP. Complications of local anaesthesia for ophthalmic Onset of action: 1 2 min. – – surgery. Br J Anaesth 1995;75:93 6. Duration: 2 9h. 5. Antonio Aldrete J, David A. Johnson. to local Elimination half life: 3–4h. anesthetics. JAMA 1969;207(2):356–7. 6. Jaichandran VV, Vijaya L, George RJ, Bhanulakshmi IM. Ropivacaine Peribulbar anesthesia for cataract surgery: effect of lidocaine warming and alkalinization on injection pain, motor and Belongs to amide group. sensory nerve blockade. Indian J Ophthalmol 2010;58:105–8. Available as 0.5% solution. 7. Mackay W, Morris R, Mushlin P. Sodium bicarbonate attenuates Dose: 2–3 mg/kg. pain on skin infilatration with lidocaine, with or without 0.5% ropivacaine solution contains 5 mg per ml epinephrine. Anesth Analg 1987;66:572–4.

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8. Putnam LP. Pseudocholinesterase deficiency: an additional 15. Guise P, Laurent S. Sub-tenon’s block: the effect of preoperative consideration on outpatient diagnostic procedures. hyaluronidase on speed of onset and block quality. Anaesth Southern Medical Journal 1977;70:831–2. Intensive Care 1999;27:179–81. 9. Chung SJ, Andrews D. Prolonged postoperative 16. Alwitry A, Chaudhary S, Gopee K, Butler TK, Holden R. Effect succinylcholine-induced apnea with pseudocholinesterase of hyaluronidase on ocular motility in sub-Tenon’s anesthesia: deficiency. Journal of the Tennessee Medical Association randomized controlled trial. J Cataract Refract Surgery 1982;8:535–6. 2002;28:1420–3. 10. Fred M, Wilson II M.D. Adverse external ocular effects of 17. British National Formulary. London: A joint publication of the topical ophthalmic medications. Survey of Ophthalmology British Medical Association and the Royal Pharmaceutical 1979;24(2):57–88. Society of Great Britain, 2002. 11. Dannaker , Christopher J, Maibach , Howard I., Austin. Erik 18. Ahluwalia HS, Lukaris A, Lane CM. Delayed allergic reaction to allergic contact dermatitis to proparacaine with subsequent hyaluronidase: a rare sequel to cataract surgery. Eye cross-sensitization to tetracaine from ophthalmic preparations. 2003;17:263–6. Amer J Contact Dermatitis 2001. 19. Kempeneers R, Dralands L, Ceuppens J. Hyaluronidase induced 12. Rubin A. Eye blocks. In: Wildsmith JAW, Armitage EN, orbital pseudotumour as a complication of retrobulbar McLure JH, editors. Principles and Practice of Regional anaesthesia. Bull Soc Belge Ophtalmol 1992;243:159–66. Anaesthesia. London: Churchill Livingstone, 2003. 20. Moharib MM, Mitra S. Alkalinized lidocaine and bupivacaine 13. Nicoll JM, Treuren T, Acharya PA, Ahlen K, James M. with hyaluronidase for sub-Tenon’s ophthalmic block. Reg Retrobulbar anaesthesia: the role of hyaluronidase. Anesth Anal Anesth Pain Med;25:514–7. 1986;65:1324–8. 21. Jehan FS, Hagan JC 3rd, Whittaker TJ, Subramanian M. 14. Crawford M, Kerr WJ. The effect of hyaluronidase on peribulbar Diplopia and ptosis following injection of local anesthesia block. 1994;49:907–8. without hyaluronidase. J Cataract Refract Surg 2001;27: 1876–9.

How to cite this article Lakshmi Prasanna S. Local Anaesthetics and Adjuvants, Sci J Med & Vis Res Foun 2015; XXXIII:6–10.

10 Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | Major review Systemic Effects of Ophthalmic Medications

R Sujatha

Consultant Anaesthesiologist, Introduction Clinical uses Sankara Nethralaya, Topically applied eye drops can enter the systemic Phenylephrine Hydrochloride Ophthalmic Chennai, India circulation through an extensive network of con- Solution, 2.5 and 10% is used for dilatation of junctival vessels and via nasolacrimal duct from pupil. Conjunctival instillation of Phenylephrine Correspondence to: highly vascularised nasal mucosa. Hydrochloride results in maximal dilatation R. Sujatha, Quantitative data on the systemic absorption of between 45 and 60 min and recovery occurs in Consultant Anaesthesiologist, drugs after conjunctival instillation indicate that about 6 h. Darker irides tend to dilate slower than Sankara Nethralaya, 30–80% of a retained topically applied dose enters lighter irides.4 Chennai, India the general circulation.1 These systemically Dilatation of the pupil with 2.5 and 10% pre- Email: [email protected] absorbed drugs escape first pass metabolism in the parations has been studied and the results show liver and peak plasma concentration reached that the higher concentration does not necessarily between 5 and 13 min after topical installation. produce a significantly greater mydriasis.5 Simple eyelid closure and punctual occlusion for at least 2 min after eye drop instillation Dose6 reduces systemic absorption of any topical drug Adults: Apply one drop to each eye. If necessary, by up to two-thirds.2,3 this dose may be repeated once only, at least 1 h Infants and children have increased potential after the first drop. for systemic drug-induced adverse reactions for Children and the elderly: The use of phenyl- several reasons. Ocular doses in children are not ephrine 10% solution is contraindicated in these weight adjusted and are similar to doses used in groups because of the increased risks of systemic adults. However, systemic absorption may have a toxicity. greater impact in children than in adults due to Recommended dose is one drop of 2.5% their lower body mass with potentially higher phenylephrine solution. plasma concentrations reached. In infants, toxicity may be compounded by altered metabolic capacity Systemic reactions and an immature blood brain barrier. Single drop of 10% Phenylephrine eye drop con- In adults, the risk of systemic effects substantially tains 4 mg of drug and multiple application may increases in the presence of underlying diseases and result in over dosage, especially if absorption from with the use of concomitant medications which may site of administration is enhanced or if the patient interact with ocularly administered drug. is compromised by age, body size, use of con- Commonly used ophthalmic drugs with signifi- comitant medications or trauma. cant systemic effects include: 7–10 1. Dilatation drugs Systemic side effects • — Sympathomimetics phenylephrine. • Hypertension • — Para-sympatholytics Atropine, Homatropine, • Occipital headache Cyclopentolate and Tropicamide. • Subarachnoid haemorrhage 2. Anti-glaucoma medications • Ventricular arrhythmias • Alpha-adrenergic agonist—Brimonidine, • Tachycardia • Para-sympathomimetic drugs—Pilocarpine, • Reflex bradycardia • Beta blockers—Timolol, levobunolol and betaxolol, Patients at increased risk for side effect are those with7 • Carbonic-anhydrase inhibitors • Insulin-dependent diabetes • Mannitol. • Idiopathic orthostatic hypotension • Cardiac disease • Hypertension Dilatation drugs • Thyrotoxicosis Phenylephrine • Aneurysms Mechanism of action • Phenylephrine is a direct acting sympathomimetic Advanced arteriosclesosis agent. It predominantly acts on alpha adrenergic • Atropine predmedication receptors. • Extremes of age (very young and old)

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• Disturbed Corneal epithelial barrier (Intraop/ • Mad as a hatter (psychosis/agitation) trauma/inflammation) • Blind as a bat (non-reactive mydriasis) and • Decreased lacrimation (Under general • Stuffed as a pipe (ileus and urinary retention) anaesthesia) Atropine Contraindications Atropine is the most potent mydriatic and cyclo- In patients who are taking monoamine oxidase plegic agent. (MAO) inhibitors (upto 3 weeks after their dis- continuation), tricyclic anti-depressants as they Systemic reactions potentiate vasopressor effect of phenylephrine and Two mechanisms appear operative in cases of beta-blockers. atropine poisoning.12,13 First, in some children a definite idiosyncratic Parasympatholytics (anticholinergics) response occurs, consisting of acute systemic tox- Mechanism of action icity and even death after the instillation of only Parasympatholytic agents blocks the cholinergic one or two drops in each eye. response of the iris sphincter and ciliary muscle, The second mechanism of atropine toxicity is causing mydriasis and cycloplegia (paralysis of overdosage following multiple instillations of the accommodation) drug, often when early toxic symptoms are not recog- nized. Single drop of atropine drops 1% (i.e. 0.05 ml) Clinical uses contains 0.5 mg of atropine. Atropine appears rapidly • Mydriasis and/or cycloplegia in blood and plasma concentration peak approxi- mately 10 min after conjunctival instillation. • Cycloplegic refraction and • fl Pupillary dilatation desired in in ammatory Symptoms of atropine toxicity7 conditions of the iris and uveal tract • Dry mouth • fl Ocular anticholinergic agents Diffuse cutaneous ush • Fever

Drugs Time to Recovery Time to Recovery Dose • Urinary retention maximal (h) maximal • mydriasis cycloplegia Tachycardia (min) • Somnolance Atropine 30–40 7–10 3–6h 7–14 1% One • Excitement and hallucinations days drop Cyclopentone 30–60 1 25–75 min 6–24 h 0.5, One Parents must be advised of the early signs of 1% drop toxicity. Drying of the mouth is the first sign of Homatropine 20–30 1–430–60 min 1–2 2, 5% One toxicity, slightly higher doses produce facial flush- days drop ing and inhibit sweating. CNS manifestations Tropicamide 20–40 6 30–40 min 2–6 h 0.5,1% One drop occur later. Infants and young children have fewer symptoms of CNS excitation and are more likely to show CNS depression with drowsiness and Systemic adverse effects 16 Central anti-cholinergic syndrome is a clinical coma. Hyperpyrexia may reach alarming levels entity which shows central and peripheral effects in infants (109°F [41.1°C] or greater), and abdom- produced by over dosage or abnormal reaction inal distention usually is pronounced. (idiosyncratic response) to clinical dosage of para- Patients at increased risk for side effect are sympatholytic (anti-cholinergic) drugs. The central nervous changes may range from • infants14 hallucinations to unconsciousness This behaviour • blond children consists of agitation including seizures, restlessness, • children with spastic paralysis or brain hallucinations, disorientation or signs of depression damage14,15 such as stupor, coma and respiratory depression. • children with akinetic seizures17 Patients might present with tachycardia, hyperten- • ’ 18–20 sion and hyperthermia. They may also display down s syndrome urinary retention, and decreased bowel activity. Homatropine hydrobromide (1%) Mnemonics to remember signs and symptoms of the Homatropine is a weaker cycloplegic agent than anticholinergic syndrome are atropine. • Red as a beet (cutaneous vasodilation) Systemic reactions • Dry as a bone (anhidrosis) Systemic toxic reactions following ocular instilla- • Hot as a hare (hyperthermia) tion are similar to those for atropine. Walsh and

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Hoyt21 stated that untoward reactions are milder compounded by the stress of manipulation. with homatropine than with atropine, but Awareness of the potential gastrointestinal com- Hoefnagel16 did not find this so in his study. plications after ROP screening using mydriatics should prompt clinicians and nurses to watch Cyclopentolate more closely for signs of feeding intolerance fol- Cyclopentolate hydrochloride has a rapid onset of lowing ROP screening to help reduce serious com- action and shorter duration of action than atro- plications such as necrotizing enterocolitis. pine or homatropine. The cycloplegic effect is Toxic reactions in children and adolescents are superior to that of homatropine. much less common with the 1% compared with the 2% solution.24 Systemic adverse reactions are Systemic reactions rarely encountered with the use of the 0.5% con- The onset of cyclopentolate toxicity occurs within centration in children. 20–30 min of drug instillation, and although usually transient (subsiding in 4–6 h), the symp- Tropicamide toms can last 12–24 h. Tropicamide (Mydriacyl) is a rapid-acting mydria- Systemic toxicity induced by the ocular adminis- tic with mild and transient cycloplegic action. In tration of cyclopentolate is similar to that produced Down syndrome, mydriatic response is three times by atropine, except that cerebellar dysfunction, greater in comparison with healthy patients. visual and tactile hallucinations are more constant Tropicamide has shown to have a lower affinity and striking features of cyclopentolate toxicity. This for systemic musacranic receptors. Therefore, is not surprising, because cyclopentolate is structur- lower incidence of systemic side effects. ally similar to atropine but contains a dimethylated Clinical uses – – side group ( N [CH3]2) also found in some tranquili- Since tropicamide is devoid of any vasopressor zers and hallucinogenic drugs. effect, it is probably one of the safest mydriatic in patients with hypertension, angina or other car- Systemic adverse effect diovascular diseases. • Drowsiness Glaucoma medications • Disorientation Pilocarpine hydrochloride • Restlessness Mechanism of action • Cerebellar dysfunction (incoherent speech, Direct acting para-sympathomimetic (cholinergic) ataxia) agent. It increases aqueous outflow. • Visual and tactile hallucinations • Gastrointestinal toxicity Clinical uses Used in acute angle closure glaucoma. Seizures and acute psychosis are especially prom- 22–31 32–35 inent in children and elderly. The psych- Systemic adverse effects7 osis is characterized by disorientation, dysarthria, • ataxia, hallucinations and retrograde amnesia. Rare but on repeated administration may This seems to indicate that CNS immaturity or increase parasympathetic tone aging is necessary for its potent psychotomimetic • Salivation action to become manifest.26 • Sweating Peripheral symptoms typical of atropine, such • Increased gastrointestinal motility (vomiting fl as ushing of skin and dryness of mouth is not and diarrhoea) been absorbed in cyclopentalone in children or • Relaxation of urethral and anal sphincters adults. (incontinence) Gastrointestinal toxicity consisting of ileus or • gastroenteritis has been observed with cyclopento- Bronchospasm in susceptible patients late concentrations of 0.5% or greater in preterm infants, due to reduced gastric acid secretion and Brimonidine volume.26,27 Gastrointestinal effects can be mini- Mechanism of action mized by delaying feeding until after the applica- It is a selective adrenergic alpha 2 agonist that tion of eye drops and ocular examination have readily crosses blood drain barrier. been performed. Brimonidine has a dual mechanism of IOP low- A case series in 50 neonates confirmed a sig- ering: it both reduces aqueous humour production nificantly higher incidence of feeding intolerance and stimulates aqueous humour outflow through (abdominal distension and increased gastric aspi- the uveoscleral pathway.37 rates) in the 24 h after ROP screening, using phenylephrine and cyclopentolate as mydriatics.36 Indications The pharmacological action of the drugs could be Reduction of IOP.

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Availability Mechanism of action The original brimonidine 0.2% formulation has a Decrease the production of aqueous humour.

pH of 6.4 and is preserved with benzalkonium 7 chloride (BAK). BAK is the antimicrobial preserva- Systemic adverse effects tive most commonly used in ophthalmic solutions, Eye drops with beta blocking action can have a but chronic exposure to solutions containing high strong and prolonged systemic effects. concentrations of BAK has been associated with Central nervous system harmful effects on the corneal surface. More • recently, a 0.1% formulation of brimonidine pre- Headache served with Purite at a pH of 7.7 was introduced. • Lethargy • Lightheadedness Systemic adverse effect38–40 • Weakness • • Drowsiness Depression • • Shortness of breath Dissociative behaviour • • Dizziness Memory loss • Headache Cardiovascular • Low mood • Bradycardia The frequency of systemic adverse effects (drowsi- • Palpitation ness, shortness of breath, dizziness, headache, low • Systemic hypotension 41,42 mood) in adult series varies from 20 to 52%, • Syncope with one study showing them to be more common • Congestive cardiac failure in patients older than 60 years42 and another showing increased drug concentration to be a risk Respiratory factor (three concentrations tested: 0.08, 0.2 and • Bronchospasm 0.5%).43 Terminations of because of adverse • effects in adults were as low as 4% 9 in one study Dyspnoea and as high as 26% in another 10 (approximately • Pulmonary oedema twice as many systemic as local side effects, a • Exacerbation of asthma similar finding to our study in children). A minor reduction in adult systolic blood pressure (2.8 Gastrointestinal mmHg, SD = 20, n = 34) associated with brimonidine • Nausea 0.2% has been reported with no effect on diastolic • Vomiting blood pressure or pulse rate.44 Acute psychosis has • Diarrhoea been reported in one 68-year-old man.45 • Abdominal pain Patients at increased risk for side effect are those with Orthopaedic Cardiac disease (angina, infarction, heart failure),44 Depression. • Joint pain Patients at increased risk for side effect are7 Contraindications • Patients receiving MAO inhibitor therapy. Diabetes (May block the typical systemic mani- Patients on antidepressants which affect nora- festations of hypoglycemi) drenergic transmission (e.g. tricyclic antidepres- • Hyperthyroidism since beta blockade may sants and mianserin). mask their symptom Neonates and in children <2 years of age. • Cardiac failure Under the age of 2 years, there have been • First degree heart block reports of apnoea, bradycardia, hypothermia, • Periperal arterial disorders (Raynaulds hypotonia, lethargy and unresponsiveness on syndrome) receiving brimonidine treatment.39 • Myasthenia gravis • Deaths secondary to bronchospasm and Beta-blockers cardiac arrest have been reported in asthmatic Indications Open angle glaucoma. and elderly patients

Contraindications Commonly used agents Timolol, levobunolol, andbetaxolol. Timolol and • In patients with history of asthma levobunolol are non-selective for beta1 and beta2 • Second or Third degree heart block not con- receptors, while betaxolol is betal-selective. trolled with pacemaker

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Interaction with other drugs Hepatic cirrhosis. Timolol may enhance the effect of the oral medi- Patient who are on high dose aspirin. cines beta blocker, ca channel blocker, digoxin, anti arrhythmics (amiodrone). I.V. Mannitol Mechanism of action Carbonic anhydrase inhibitors Hyperosmotic agent which reduces IOP by reduc- Mechanism of action tion of vitreous volume which results reduction It decreases rate of aqueous humour production. The from water transfer formed by osmotic gradient onset of IOP reduction begins 1 h and maximum IOP between retina, choroid and vitreous. reductions occurs 2–5 h after oral administration. The duration of action is about 6–8h. Indications Short-term management acute and marked eleva- Dose tion of IOP and perioperative management of Patients can be started on a low daily dosage of certain glaucoma patients. acetazolamide, such as 62.5 or 125 mg four times Available as 20% IV solution. daily and advanced to 250 mg four times daily as necessary and tolerated. Dosages are generally Dosage limited to a total of 1000 mg daily because a 0.5–2 gm/kg body weight IV given over a period higher dosage is associated with more frequent of 30–60 min. and severe side effects. The dosage in infants and Doses as low as 0.25 gm/kg body weight may be children is 5–10 mg/kg administered every 4–6h. effective too. Lower dose may be effective if IOP is notveryhighorincreaseinIOPisdueto Systemic side effects inflammation.53 Relative hypokalemia and hyponatremia.46,47 47 Mild mixed respiratory and metabolic acidosis. Side effects53 Formation of renal stones. Liver failure, characterized by confusion, aster- • Headache ixis and elevated blood ammonia, may be seen in • Pain in upper extremities patients with chronic liver diseases. the mechan- • Nausea and vomiting ism by which carbonic anhydrase inhibitors (CAIs) • Diuresis cause liver failure remains unclear. • Dehydration Blood dyscrasias, including aplastic anaemia, • fi agranulocytosis, thrombocytopenia and neutro- Potassium de ciency penia, have been documented in patients taking • Vertigo CAIs.48–50 Blood dyscrasias may be idiosyncratic, • Fever occurring after as little as a single dose of medica- • Confusion tion, or they may be dose related. • Disorientation A symptom complex of malaise, fatigue, • Congestive cardiac failure weight loss, depression, anorexia and often loss of • libido has been reported in up to 48% of patients. Used with caution in patients The patients in one study51 who complained of • Renal failure this symptom complex were more acidotic than • Congestive cardiac failure those without such complaints. • Electrolyte abnormalities Paresthesias in the proximal and distal extrem- • Confused mental state ities have been reported in up to 75% of • Dehydration patients.52 This side effect usually does not neces- sitate the discontinuation of the drug and tends to Absolute contraindication diminish with chronic use. Hypersensitivity to mannitol. Patients may complain of strange tastes occur- ring during consumption of carbonated beverages. Conclusion Similar complaints have been elicited when CA The ocular medications have varying systemic has been topically dispensed on the tongue. effects ranging from trivial to life threatening signs and symptoms. These systemic effects can Used in caution be caused by the ocular medications per se or may Patients who are on diuretics. due to interactions with oral medications taken for Chronic abstructive respiratory disease. underlying systemic illness. Hence, before pre- Sickle cell trait. scribing these medications, it is very important for Renal failure. an ophthalmologists to know about the patient’s systemic conditions and current medications. In Contraindications general, these medications should be used cau- Hypersensitivity to sulpha drugs. tiously in extremes of age groups.

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References 29. Kellner V, Esser J. Acute psychosis caused by poisoning with 1. Huana TC, Lee DA. Punctal occlusion and topical medications cyclopentolate. Klin Monatsbl Augenheilkd 1989;194:458–61. for glaucoma. Am J Ophthalmol 1989;107:151. 30. Hanson RM, West C, Fitzgerald DA, et al Seizures associated with 2. Aritwk N, Oge I, Erkan D, et al The effects of nasolacrimal 1% cyclopentolate eyedrops. J Pediat Child Health 1990;26:196–7. canal blockage on topical medications for glaucoma. Acta 31. Mwanza JC. Cyclopentolate and grand-mal seizures. Bull Soc Ophthalmol Scand 1996;74:411–3. Belge Ophtalmol 1999;273:17–8. 3. Lee VHL, Robinson JR. Review: topical ocular drug delivery: 32. Mark HH. Psychotogenic properties of cyclopentolate. JAMA recent developments and future challenges. J Ocul Pharmacol 1996;186:430. Ther 1986;2:67–108. 33. Carpenter WT. Precipitous mental deterioration following 4. Gambill HD, Ogle KN, Kearns TP. Effect of four drugs 0 cycloplegia with 0.2% cyclopentolate HCl. Arch Ophthalmol Mydriatic determined with pupillograph. 1967;78:445–7. 5. Chawdhary S, Angra SK, Zutshi R, Sachev S. Mydriasis—use of 34. Awan KJ. Adverse systemic reactions of topical cyclopentolate Phenylephrine (a dose-response concept). Ind J Ophthalmol hydrochloride. Ann Ophthalmol 1976;8:695–8. 1984;34:213–6. 35. Hermansen MC, Sullivan LS. Feeding intolerance following 6. Minims Phenylephrine Hydrochloride 2.5% w/v, Eye drops ophthalmologic examination. Am J Dis Child solution. www..org.uk/emc/medicine/17618. 1985;139:367–368164. 7. Bartlett JD, Jaanus SD. Clinical Ocular Pharmacology, 2013. 36. Kaila T, Huupponen R, Salminen L, et al Systemic absorption of Butterworth-Heinemann. ophthalmic cyclopentolate. Am J Ophthalmol 1989;107:563–4. 8. Fraunfelder FT, Scafidi AF. Possible adverse effects from topical 37. Toris CB, Gleason ML, Camras CB, et al Effects of brimonidine ocular 10% phenylephrine. Am J Ophthalmol 1978;85(4):447–53. on aqueous humor dynamics in human eyes. Arch Ophthalmol 9. Kumar V, Schoenwald RD, Chien DS, Packer AJ, Choi WW. 1995; 113:1514–7. Systemic absorption and cardiovascular effects of phenylephrine 38. Carlson JO, Zabriskie NA, Kwon YH, et al Apparent CNS eyedrops. Am J Ophthalmol 1985;99(2):180–4. depression in infants after the use of topical brimonidine. Am J 10. Wilensky JT, Woodward HJ. Acute systemic hypertension after Ophthalmol 1999;128:255–6. conjunctival instillation of phenylephrine hydrochloride. Am J 39. Berlin RJ, Leo VT, Samples JR, et al Ophthalmic drops causing Ophthalmol 1973;76(1):156–7. coma in an infant. J Pediatr 2001;128:441–4. 11. Brunton L, Chabner BA, Knollman B. Goodman and Gilman’s 40. Enyedi LB, Freedman SF. Safety and efficacy of brimonidine in The Pharmacological Basis of Therapeutics. McGraw Hill, children with glaucoma. JAAPOS 2001;5:281–4. New York, Chicago. 41. Serle J and the brimonidine study group III. A comparison of 12. Morton HG. Atropine intoxication: its manifestations in infants the safety and efficacy of twice daily rimonidine 0.2% versus and children. J Pediatr 1939;:755. betaxolol 0.25% in subjects with elevated intraocular pressure. 13. Heath WE. Death from atropine poisoning. Br Med J 1950;2:608. Surv Ophthalmol 1996; 41 (Suppl. 1):S39–47. 14. Unna KR, Glaser K, Lipton E, et al Dosage of drugs in infants 42. Detry-Morel M, Dutrieux C. Treatment of glaucoma with and children: I. Atropine. 1950;6:197. brimonidine (Alphagan 0.2%). J Fr Ophtalmol 2000; 23 15. Apt L. Pharmacology. In Isenberg SJ (ed). The Eye in Infancy, (8):763–8 (French). 2nd ed., pp. 87–98. St Louis, Mosby, 1993. 43. Derick RJ, Robin AL, Walters TR, et al Brimonidine tartrate. 16. Hoefnagel D. Toxic effects of atropine and homatropine eye A one month dose response study. Ophthalmol 1997; drops in children. N Engl J Med 1961;264:168. 104:131–6. 17. Wright BD. Exacerbation of akinetic seizures by atropine 44. Waldock A, Snape J, Graham CM. Effects of glaucoma eyedrops. Br J Ophthalmol 1992;76:179–80. medications on the cardiorespiratory and intraocular pressure 18. Berg JM, Brandon MW, Kirman BH. Atropine in mongolism. status of newly diagnosed glaucoma patients. Br J Ophthalmol Lancet 1959;2:441. 2000; 84(7):710–3. 19. Priest JH. Atropine response of eyes in mongolism. Am J Dis 45. Kim DD. A case of suspected alphagan-induced psychosis. Arch Child 1960;100:869. Ophthalmol 2000; 118(8):1132–33. 20. Harris WS, Goodman RM. Hypersensitivity to atropine in 46. Brechue WF, Stager JM, Lukaski HC. Body water and electrolyte Down’s syndrome. N Engl J Med 1968;279:407–10. responses to acetazolamide in humans. J Appl Physiol 21. Walsh FB, Hoyt WF. Clinical Neuro-Ophthalmology, 3rd ed, 1990;69:1397. p. 2655. Baltimore, Williams & Wilkins, 1969. 47. Nadell J, Kalinsky H. The effects of the carbonic anhydrase 22. Simcoe CW. Cyclopentolate (Cyclogyl) toxicity. The report of a inhibitor “6063” on electrolytes and acid-base balance in two case. Arch Ophthalmol 1962;67:406–8. normal subjects and two patients with respiratory acidosis. J 23. Beswick JA. Psychosis from cyclopentolate. Am J Ophthalmol Clin Invest 1953;32:622. 1962;53:879–81. 48. Rentiers PK, Johnston AC, Buskard N. Severe aplastic anemia as 24. Binkhorst RD, Weinstein GW, Baretz RM, et al Psychotic a complication of acetazolamide therapy. Can J Ophthalmol reaction induced by cyclopentolate (Cyclogyl). Am J 1970;5:337. Ophthalmol 1963;55:1243–5. 49. Lubeck MJ. Aplastic anemia following acetazolamide therapy. 25. Adcock EIII. Cyclopentolate (Cyclogyl) toxicity in pediatric Am J Ophthalmol 1970;69:684. patients. J Pediatr 1971;79:127–9. 50. Wisch N, Fischbein FL, Siegel R, et al Aplastic anemia resulting 26. Kennerdal JS, Wucher FP. Cyclopentolate associated with two from the use of carbonic anhydrase inhibitors. Am J cases of grand mal seizure. Arch Ophthalmol 1972;87:634–5. Ophthalmol 1973;75:130. 27. Bauer CR, Trepanier-Trottier MC, Stern L. Systemic 51. Epstein DL, Grant WM. Carbonic anhydrase inhibitor side cyclopentolate (Cyclogyl) toxicity in the newborn infant. J effects: serum chemical analysis. Arch Ophthalmol Pediatr 1973;82:501–5. 1977;95:1378. 28. Khurana AK, Ahluwalia BK, Rajan C, et al Acute psychosis 52. Leopold IH, Eisenberg IJ, Yasuna J. Experiences with Diamox. associated with topical cyclopentolate hydrochloride. Am J Am J Ophthalmol 1955;39:885. Ophthalmol 1988;105:91. 53. Peter A. Netland Glaucoma Medical Therapy. Principles and Management, 2nd edn, 2007.

How to cite this article Sujatha R. Systemic Effects of Ophthalmic Medications, Sci J Med & Vis Res Foun 2015; XXXIII:11–16.

16 Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | Major review Systemic Evaulation of Patients for Ophthalmic Surgery under Regional Anaesthesia

V Jagadeesh

Director, Department of The practice of has become more • History of systemic disease with special Anaesthesiology, outcome driven and cost conscious and we clini- emphasis on symptoms related to cardiovascu- Sankara Nethralaya, cians need to re-evaluate and streamline methods lar and respiratory system. Chennai, India of patient care. • The ability to lie flat. A pre-operative evaluation is important to • All current medications. Correspondence to: • V. Jagadeesh, Screen for and optimize co-morbid conditions. • , idiosyncratic drug reactions. Director, Department of • Assess and lower the risk of anaesthesia and Anaesthesiology, surgery. • Past surgery and any complications. Sankara Nethralaya, Chennai, India • Establish baseline results to guide peri- • Past anaesthetic procedures and any Email: [email protected] operative decisions. complications. • Facilitate timely care and avoid cancellations • Psychosocial matters including anxiety, confu- on the day of surgery. sion, panic attacks and claustrophobia. Ophthalmic procedures are considered low risk • Communication issues with respect to dialect, because of their general lack of physiological dis- deafness and dementia. turbances.1 However, ophthalmic patients are often elderly and have multiple co-morbid condi- Examination tions that are a constant threat to well being, even • without surgery. General examination. The goals of pre-operative evaluation are the • Cardiovascular system: heart sounds, murmur. following: • Respiratory system: breath sounds and adventi- 1 To evaluate patient readiness for anaesthesia tious sounds. and surgery. 2 To optimize the patient’s health before surgery. Investigations In general, tests should only be considered when 3 To enhance the quality of peri-operative care. the history or physical findings would have indi- 4 To reduce surgical morbidity and length of cated the need for an investigation even if surgery hospital stay. had not been planned.2 However, some specific tests which are routinely indicated include the 5 To answer all questions and obtain informed following. consent. • Clotting profile should normally be checked At a minimum, a pre-operative visit should within 24 h of surgery for patients on include the following: anti-coagulants. • Interview the patient to review medical, anaes- thesia, surgical and medication history. • Electrolytes on the day of surgery for patients on dialysis. • Conduct an appropriate physical examination. • Review the pertinent diagnostic data. For the patient with no history of significant systemic disease and no abnormal findings on • Refer the patient to primary care or specialist examination at the /anaesthetist led physician to manage new or poorly controlled assessment, no special investigations are diseases. indicated. • Formulate and discuss care plan with patient or responsible adult. Specific disorders for consideration in Pre-operative assessment pre-operative assessment History Hypertension The following should be noted during history Hypertension should be well controlled before the taking. patient is scheduled for surgery and should not be • Patient’s age. lowered immediately prior to surgery. It is generally

Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | 17 Major review

recommended that elective surgery be delayed for needs to be stopped for surgery, then elective severe hypertension until the blood pressure is surgery should be deferred for 12 months after below 180/110 mmHg. Patients who are taking drug-eluting stent implantation and at least anti-hypertensive medication should continue their 6 weeks following bare metal stent insertion.4 If drugs up to and including the day of surgery. there are concerns that anti-platelet agents may complicate surgery, then the medical team that Diabetes mellitus started treatment should be consulted to discuss Poor glycaemic control is associated with stopping these agents. increased risk of heart failure Both systolic and diastolic dysfunction may be present Tighter peri- Valvular heart disease operative control is warranted to reduce risk of There is no need for systemic antibiotic prophy- 5 infections. The American College of endocrinolo- laxis for ophthalmic surgery. gists position statement recommends a target fasting glucose of <110 mg/dl and a post-prandial Pacemakers and implantable cardioverter blood glucose of 140–200 mg/dl in non-critically defibrillators ill patients.3 The goal of peri-operative diabetic Management of these complex devices should be management should me be to avoid hypogly- directed at protecting the patient and preventing caemia and marked hyperglycaemia. inappropriate functioning. The team At present evidence suggests that a patient should be consulted to identify the device and with good control of blood sugar pre-operatively advise whether it needs to be disabled or can be taken up for surgery with random blood re-programmed in the peri-operative period. sugar levels up to 250 mg/dl. Diabetic patients should have their usual medication and diet if Chronic obstructive pulmonary disease surgery is planned under local anaesthesia (LA). Patients who have chronic obstructive pulmonary disease, asthma or a cough may not be able to lie supine for an extended period of time. Hypoxemia Cardiac disease can occur in the elderly purely by adopting the Particular attention to be paid to the following: supine position. Treating exacerbation of their • Need to identify the presence of heart disease. disease like infection or bronchospasm may make it possible for them to remain recumbent and still and • Need to know the severity of heart disease. this is necessary to decrease complications. Oxygen • Need to evaluate the significant risk of heart supplementation is recommended. Accumulation of disease based on associated conditions (DM, carbon dioxide occurs with several types of draping renal insufficiency, cerebrovascular or periph- system.6 This can lead to anxiety, as well as hyper- eral vascular disease). tension and increased choroidal blood flow. An open draping system, suction or a simple high flow • Determine the need for pre-operative consult- oxygen-enriched air system below the drapes may ation and interventions to modify risk of pre- reduce carbon dioxide accumulation.7 operative events. Patients with high risk conditions like Chronic renal failure • Unstable or recent onset angina. The focus of the pre-operative evaluation of patients with renal insufficiency or failure should • Decompensated heart failure. be on the cardiovascular and cerebrovascular fl • Significant arrhythmias. systems, uid volume and electrolyte status. Chronic metabolic acidosis is common but usually • Severe valvular disease. mild and compensated for by chronic hyperventilation. Would require cardiology consultation for The preparation of patients undergoing dialysis stabalizing their medical condition prior to surgery. requires close liaison with the dialysis unit. Blood biochemistry should be optimized and careful attention paid to the patient’s hemodynamic Patients with myocardial infarction should not status and ability to lie flat. Arterio-venous fistula have surgery within 3 months of the infarct. should be noted and protected. The blood pressure Non- soon after bypass grafting cuff should not be applied to the same limb as the or percutaneous coronary interventions is asso- fistula. Intravenous access should be secured at a ciated with high risk of peri-operative cardiac site remote from arterio-venous fistulae. morbidity and mortality. Patients who have had a recent cardiac thera- Neurologic diseases peutic intervention have a higher risk of subse- A history focused on recent events, exacerbations quent myocardial events. If anti-platelet therapy or evidence for poor control of the medical

18 Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | Major review condition is necessary for a patient who has neuro- to be derived from stopping aspirin is, at best, logic disease like stroke, seizure disorder, multiple questionable. It is therefore recommended that sclerosis, Parkinson’s disease. If a stroke or transient low-dose aspirin should not be stopped prior neurologic deficithasnotbeenfullyevaluatedor to cataract surgery under LA. has occurred within 1 month, elective surgery 4 Patients on clopidogrel, dipyridamole or combi- should be delayed pending complete evaluation. nations of these with aspirin are usually on Patients who have significant movement disorder or these drugs for sound medical reasons. poorly controlled seizures may require general Withdrawal of the drugs in these circumstances anaesthesia. may lead to dangerous thromboembolic events. Anaemia It is therefore recommended that these drugs should not be stopped for cataract surgery. Consequences form moderate levels of anaemia and Hb levels ≥7 gm/dl in patients without CAD are minimal. The focus of the pre-operative visit is to Conclusion determine the aetiology, duration and stability of The prevention of complication during and after the anaemia, and the patient’s co-morbid conditions procedure is the most important goal of pre- that may impact oxygenation, such as pulmonary, operative evaluation. Identification of risk requires cardiovascular and cerebrovascular disease. good medicine, system of care, clinical and lab assessment and experienced, knowledgeable, dedi- Anti-coagulated patients cated health care providers. Many patients undergoing ophthalmic surgery Risk reduction is the ultimate goal of preopera- have significant co-morbidity. Many take anti- tive assessment and management. coagulant or anti-platelet drugs. Stopping these drugs in patients with heart or vascular disease may result in death from a thromboembolic episode. The risk of this must be balanced against References the risk of bleeding. In general, the risks of stop- 1. Eagle KA, Berger PB, Calkins H, et al. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac ping these drugs outweigh the risks of ophthalmic surgery—executive summary: a report of the American College of surgery, which is in most cases confined to the Cardiology/American Heart Association Task Force on Practice eye. The majority of eye surgery is now performed Guidelines (Committee to Update the 1996 Guidelines on under LA. There is no strong evidence currently to Perioperative Cardiovascular Evaluation for Noncardiac Surgery). favour blunt cannula techniques such as J Am Coll Cardiol 2002;39(3):542–53. sub-Tenon’s block over traditional sharp needle 2. Keay L, et al. Routine pre-operative medical testing for cataract peribulbar block in patients on anti-coagulant or surgery. Cochrane Database of Syst Rev 2009;15(2):CD007293. 3. Garber AJ, Moghisi, et al. American college of anti-platelet therapy. position statement on inpatient diabetes and metabolic control. 4. Korte W, et al. Peri-operative management of antiplatelet therapy Recommended best practice based on the in patients with coronary artery disease. Joint position paper by clinical experience of the British Ophthalmic members of the working group on Peri-operative Haemostasis of Anaesthesia Society Anti-coagulant the Society on Thrombosis and Haemostasis Research (GTH), the Guideline Development Group8 working group on Peri-operative Coagulation of the Austrian Society for , Resuscitation and Intensive Care 1 In general, patients with prosthetic heart (ÖGARI) and the Working Group Thrombosis of the European valves and coronary stents should not have Society for Cardiology (ESC). Thromb Haemost 2011;105 anti-coagulant or anti-platelet agents discon- (5):743–9. tinued for cataract surgery. 5. Prophylaxis against infective endocarditis. Antimicrobial prophylaxis against infective endocarditis in adults and children 2 We recommend continuing warfarin for undergoing interventional procedures. NICE clinical guideline 64. routine cataract surgery. The International NICE March 2008. Normalized Ratio (INR) must be checked close 6. Schlager A. Accumulation of carbon dioxide under ophthalmic drapes during eye surgery: a comparison of three different to the time of surgery, ideally on the same drapes. Anaesthesia 1999;54(7):690–4. day, and the INR should be within the range 7. Inan UU, Sivaci RG, Oztürk F. Effectiveness of oxygenation and that is determined by the condition for which suction in cataract surgery: is suction of CO2-enriched air under the patient is being anti-coagulated. the drape during cataract surgery necessary? Eye (Lond) 2003;17 (1):74–8. 3 Patients who self-medicate or receive pre- 8. Loco-regional anaesthesia for ocular surgery: anticoagulant and scribed low-dose aspirin may have a slightly antiplatelet drugs Stephen J. Mather, K.-L. Kong, Shashi B. Vohra increased risk of haemorrhage but the benefit Current Anaesthesia & Critical Care.

How to cite this article Jagadeesh V. Systemic Evaulation of Patients for Ophthalmic Surgery under Regional Anaesthesia, Sci J Med & Vis Res Foun 2015;XXXIII:17–19.

Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | 19 Major review Preoperative Instructions and Preparation of Patients Posted for Cataract Surgery

Sonali Raman

Consultant Anaesthesiologist, Introduction postoperative pain.3 Similarly, Giraudet-Le Sankara Nethralaya, Patient education and adequate time to listen and Quintrec et al. also showed that a multidisciplinary Chennai 600 006, respond are integral components in an outpatient standardized information session also significantly Tamil Nadu, India 1 Email: [email protected] cataract surgical approach. The provision of minimises both preoperative anxiety and post- good-quality preoperative information facilitates operative pain in patients undergoing surgery.4 patients’ active involvement in their care, and Correspondence to: therefore may contribute to an overall increase in Whom to give instructions? Sonali Raman, satisfaction.2 Delivery of a safe anaesthetic It should be given to the patient; however, in Consultant Anaesthesiologist, requires current, objective information prior to the cases of paediatric cases and in cases where Sankara Nethralaya, surgical procedure. The patient’s medical status Chennai 600 006, patient cannot comprehend and understand the Tamil Nadu, India should be stable, optimized and documented. instructions, it should be given to the attendant Email: [email protected] Laboratory testing is warranted under certain cir- adult. Preferably the instructions should be given cumstances, although these requirements are in local vernacular language. becoming less frequent. This article discusses two important aspects: Preoperative instructions and Instructions related to systemic preparation of patients posted for cataract surgery medications? under local anaesthesia. Antihypertensive medicine Patients commonly present with either diagnosed Preoperative instructions or undiagnosed hypertension. Even if a patient Who should give instructions? carries the diagnosis of hypertension and takes This has to be a teamwork of ophthalmologist, antihypertensive therapy, the hypertension may be paramedical staff, physician and anaesthetist who poorly controlled. Patients should continue taking should work as a unison in giving instructions. It preoperative antihypertensive medications is a good idea to divide the task as follows: throughout the entire perioperative period. Patients with hypertension are at a higher risk for a Ophthalmologist: Gives instructions regarding labile BP and for hypertensive emergencies during eye medications. surgery. They should continue the medication b Paramedical staff (Surgery Fixing centre): even on the day of surgery.5 Gives instructions related to the need for attendant, arrival time at hospital and general Medicines for cardiac illness instructions. Many studies have shown a significantly higher c Anaesthesiologist/Physician: Gives instructions odds Ratio of various cardiovascular disorders and cardiovascular risk factors in cataract patients regarding the preoperative fasting and systemic 6–8 medications. undergoing surgery. It is advisable to continue the medications in perioperative period and on the day of surgery. When to give instructions? Preferably all instructions should be given within Antidiabetic medications a week of a planned ocular surgery. Once, after Patients with type 2 diabetes are advised to con- evaluation by an ophthalmologist, the patient tinue routine oral hypoglycaemic medications agrees for the surgery, the instructions can be along with their regular breakfast. Blood sugar to given by the ophthalmologist during the same be determined on the day of surgery. In patients visit. receiving insulin, adjust insulin dosage before the The paramedical staff should give the instruc- surgical procedure to avoid hypoglycaemia. tions when the planning for surgery is done; and Administer subcutaneous correction dose insulin anaesthetist/physician should give instructions with target glucose between 140 and 180 mg/dl. during the preoperative evaluation. Maintain postoperative glucose levels (premeal and fasting) in the range of 100–180 mg/dl in patients Verbal Vs Written? undergoing surgical procedures that are not long or It is good to have both, written and verbal. complex. Continue intraoperative management Hayward et al. had shown that structured infor- strategies into the postoperative period if the mation given to patients prior to surgery reduced patient remains unable to eat normally. Resume the

20 Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | Major review patient’s outpatient diabetic diet and treatment without moving the head. The patient has to be regimen once he or she is eating well.11 informed that his general health will be moni- tored, and an anaesthesiologist will start his intra- Antiplatelets and anticoagulants venous line and administer appropriate sedation. In general, patients with prosthetic heart valves and coronary stents should not have anticoagulant or Instructions related to hygiene antiplatelet agents discontinued for cataract surgery. Shower and head bath on the day of the surgery We recommend continuing warfarin for routine to help maintain a clean surgical environment is cataract surgery. The International Normalized advised. Patients should also wear clean, comfort- Ratio (INR) must be checked close to the time of able clothes, and avoid wearing eye make-up. surgery, ideally on the same day and the INR should be within the range that is determined by Instructions related to food intake the condition for which the patient is being anti- Patient is advised to be nil per oral 2 h before the coagulated. It is also recommended that low-dose cataract surgery. He is also adviced to take only a aspirin should not be stopped prior to cataract light breakfast. As a general rule, patients are surgery.12 asked to refrain from alcoholic beverages for at least 24 h prior to surgery. Steroids The exogenously administered corticosteroids sup- press the hypothalamus–pituitary–adrenal axis, Preoperative preparation thereby inhibiting normal endogenous adrenal Consent cortical function and subsequent release of corti- Increasing medico-legal litigation, and the desire sol. Furthermore, during conditions of stress, to provide patients with more say concerning their failure to increase plasma levels of cortisol can own treatment, has highlighted the issue of increase the risk of morbidity and/or mortality (i. informed consent and how it is obtained. In order e. inadequate or ‘failed’ stress response). Although for a patient to make a sensible decision concern- the potential consequences of a failed corticoster- ing his or her treatment, they need appropriate oid response are varied, the most life-threatening information. This may occur via discussions with includes refractory hypotension and shock states.9 medical/nursing staff, via the media/internet, or from speaking with friends who have undergone a If the patient has stopped oral steroids >3 months similar procedure. However, it chiefly occurs ago, no additional perioperative steroids are required. during the acquisition of informed consent, If he has stopped <3 months back, the perioperative during which the risks and benefits of any surgi- steroid schedule is followed as if the patient is on cal procedure are explained. steroids. If patient is on steroids (<10 mg/day) no Informed consent for elective surgery is often additional steroid coverage is required. However, if obtained by concern doctor during pre-assessment patient is on >10 mg/day steroid, besides the usual clinics, or on the day of surgery. For consent to be perioperative steroids, on the day of surgery inject- valid the patient must be competent to take the able bolus dose of steroids (25 mg Hydrocortisone) is particular decision and should have received suffi- needed. If patient is on high dose immunosuppres- cient information to make a decision. sant’s e.g. 60 mg Prednisolone, the immunosuppres- Sufficient information to make a decision sant’s are continued in perioperative period, and a should also include an explanation of (1) the risks higher bolus dose required on day of surgery 10 and benefits involved; (2) any alternative treat- (250 mg Hydrocortisone). ments and (3) the risks and benefits of doing nothing. The consent should be signed by patient Other medications if he/she can comprehend and understand and are fl Antidepressants, antianxiety, thyroid re ux medi- aged >18 years and if age is <18 years and cannot cations, asthma medications, heartburn or medica- comprehend and understand the parent/relative tions and antiseizure medications should be should sign the consent. continued in the perioperative period and also on the day of surgery. Preparation before arrival Instructions related to surgery Drops: It should be ensured that patient had The ophthalmologist gives the instructions and received instructions for appropriate drops to be counselling regarding benefits and risk involved put before surgery. These include antibiotic in cataract surgery. Patient is informed about the prophylaxis, antiglaucoma agents in selected position in which he/she has to lie down, about cases or steroid drops in selected cases. the nasal cannula that will be kept for oxygen Clothes: Patient is advised to wear comfortable and drape covering over the face during surgery. loose fitting clothing on the day of surgery It is always wise to encourage the patient to Cosmetics: Patient should not wear any cos- inform pain, if there is any, orally to surgeons metics or have makeup, lotion in and around the

Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | 21 Major review

Figure 1: Preoperative preparation for cataract surgery.

eye. Patient should refrain from wearing any kind when indicated. All events preoperative, intra- of jewellery. operative and postoperative are documented at regular intervals in an anaesthesia chart. There are Preparation in the ward separate charts made for only systemically high- All patient change their dress to a clean loose OT risk patients. dress before shifting to the theatre. They should have an identity tag on the wrist to confirm iden- Methods of monitoring in OT tity and to avoid any untoward incident. The eye There are guidelines on monitoring in ophthalmic to be operated is identified by means of a sticker practice but the most important aspects are13–15 stuck on the forehead (orange for right and green Clinical observations: These include the for left). Eye drops for dilatation usually sym- patient’s colour, respiratory movements, pulse and pathomimetic mydriatic (such as phenylnephrine responses to surgical stimuli. Pulse oximetry 2.5%) and parasympatholytic cycloplegic (such as (SpO2), Electrocardiogram (ECG) and Non-invasive tropicamide or cyclopentolate 1%) are used. blood pressure are the basic monitoring required. A checklist is prepared in the ward regarding The minimum monitoring (e.g. for a fitperson eye to be operated, investigations, status of having routine surgery under topical anaesthesia) is fasting, etc. The patient is either shifted from the clinical observation, communication and pulse inpatient ward or the ambulatory ward by means oximetry. The ECG and blood pressure should be of a stretcher or a wheel chair. monitored in sedated patients and those who are at risk of cardiovascular complications (e.g. hyperten- Preparation in operation theatre sives, patients with pacemaker, diabetics) during Once patient is received in receiving room patients surgery. name, operating surgeons name and eye to be fi operated is con rmed. Intravenous cannula is put Conclusion by either anaesthesiologist or trained nurses. During a preoperative consultation all patients Blood pressure is checked and if it is higher it is should be given clear oral instructions regarding optimized before surgery. The checklist is the type of anaesthesia to be administered, about rechecked in OT. the surgery and its prognosis, continuation of medications both oral and topical and time of nil Preparation after shifting of patient from receiving per oral to be followed. The goal of preoperative room to operation theatre evaluation is to identify and optimize conditions OT stretcher is wheeled into the OT with the so has to reduce perioperative morbidity and mor- patient and the patient is transferred to the OT tality. Preoperative investigations are helpful to table. Stretcher is wheeled out and the main doors stratify risk, direct anaesthetic choices and guide are kept closed till surgery is over. The patient is postoperative management, but often are obtained placed comfortably on the table and kept warm because of protocol rather than medical necessity. with a blanket. Alternative warming device such The decision to order preoperative tests should be as the electric warmer or therma drape are used to guided by the patient’s clinical history, comorbid- keep the patient warm. ities and physical examination findings. A multiparameter monitor for recording BP, HR, ECG and SPO2 are attached to the patient. A nasal cannula is put for all patient for oxygen at a References 1. Ruehl CA, Schremp PS. Nursing care of the cataract patient: flow rate of 2 l/min. An arch/frame is put so that today’s outpatient approach. Nurs Clin North Am 1992;27 surgical sterile drape would not cover nose and (3):727–43. mouth, see Figure 1. For patient under local 2. Walker JA. What is the effect of preoperative information on anaesthesia, monitored anaesthesia care is given patient satisfaction? Br J Nurs 2007;16(1):27–32. Review.

22 Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | Major review

3. Hayward J. Information: a prescription against pain. The Study 9. Streck WF, Lockwood DH. Pituitary adrenal recovery following of Nursing Care Project Reports, Series 2, No 5. London: Royal short-term suppression with corticosteroids. Am J Med 1979;66 College of Nursing, 1975, 18. (6):910–5. 4. Giraudet-Le Quintrec JS, Coste J, Vastel L, Pacault V, Jeanne L, 10. Clinical Guidelines for Perioperative Steroid Replacement, Royal Lamas JP, et al Positive effect of patient education for hip Cornwall Hospitals, NHS, UK. surgery: a randomized trial. Clin Orthop Relat Res 11. SAMBA Consensus Statement of Perioperative Blood Glucose 2003;414:112–20. Management in Diabetic Patients Undergoing Ambulatory 5. Lira RP, Nascimento MA, Arieta CE, Duarte LE, Hirata FE, Surgery. Girish P. Joshi, MBBS, M.D., FFARCSA. SAMBA Nadruz W. Incidence of preoperative high blood pressure in Ambulatory Anesthesia Vol. 25, No. 3. July 2010. Also, cataract surgery among hypertensive and normotensive patients. available at www.sambahq.org. Indian J Ophthalmol 2010;58(6):493–5. 12. Katz J, Feldman MA, Bass EB, Lubomski LH, Tielsch JM, 6. Hu FB, Hankinson SE, Stampfer MJ, Manson JE, Colditz GA, Petty BG, Fleisher LA, Schein OD. Study of Medical Testing for Speizer FE, et al Prospective study of cataract extraction and Cataract Surgery Team. Risks and benefits of anticoagulant and risk of coronary heart disease in women. Am J Epidemiol antiplatelet medication use before cataract surgery. 2001;153:875–81. Ophthalmology 2003;110(9):1784–8. 7. Lindblad BE, Ha°kansson N, Philipson B, Wolk A. Metabolic 13. Recommendations for Standards of Monitoring During syndrome components in relation to risk of cataract extraction: Anaesthesia and Recovery (4th edition). AAGBI, London, 2007. a Prospective Cohort Study of Women. Ophthalmology 14. Astbury N. A hand to hold: communication during cataract 2008;115:1687–92. surgery (Editorial). Eye (Lond) 2004;18:115–6. 8. Christen WG, Glynn RJ, Seddon JM. Cataract and subsequent 15. Ahmed N, et al Ocular phenylephrine 2.5% continues to be risk of cardiovascular disease (Abstract). Invest Ophthalmol Vis dangerous. BMJ Case Reports 2009; . Sci 1992;33:2026.

How to cite this article Sonali Raman. Preoperative Instructions and Preparation of Patients Posted for Cataract Surgery, Sci J Med & Vis Res Foun 2015;XXXIII:20–23.

Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | 23 Major review Choosing the Type of Anaesthesia for Cataract Surgery

Pradyna Senthil Kumar

Consultant Anaesthesiologist, Introduction Sankara Nethralaya, Good anaesthesia is essential for the performance Chennai, India of safe intraocular surgery. Advances in cataract surgery techniques have presented surgeons with Correspondence to: new options for ocular anaesthesia. As cataract Pradyna Senthil Kumar, surgery has become faster, safer and less trau- Consultant Anaesthesiologist, matic, the need for akinesia and anaesthesia has Sankara Nethralaya, declined significantly. In the present era anaesthe- Chennai, India sia for eye surgery aims at creating a comfortable Email: pradnyasenthil@ymail. environment for the patient and the surgeon com during surgery and a quick recovery of function without inherent added risks. Today there are numerous modes of anaesthesia from which surgeon can choose. The main aim of this article is to review the different choices for ocular anaes- thesia, compare their efficacies and helping to Figure 1: For inferolateral peribulbar injection select the most appropriate type of anaesthesia for recommended percutaneous needle entry site is patients posted for cataract surgery. at the junction of lateral wall and floor of the Choices for ocular anaesthesia orbit and the traditional (Yellow dot) point at Regional and general anaesthesia medial 2/3rd and lateral 1/3 rd of the inferior Regional Anaesthesia orbital margin is avoided. Akinetic techniques Needle-based technique neurovascular bundle. The initial direction of the Retrobulbar needle is tangential to the globe. Once past the Peribulbar equator, as gauged by the axial length of the Cannula-based technique globe, the needle is allowed to go upwards and 5 SubTenons block inwards. With the eye in primary gaze, 4–5ccof Non-Akinetic technique local anaesthetic agent is injected. Topical anaesthesia All extraocular muscles can be paralysed by this technique except superior oblique. The entire globe is anaesthetized as a result of blocking the Akinetic techniques nasociliary and long ciliary nerves. 1. Needle-based technique Modern retrobulbar block Advantages The aim is to block the oculomotor nerves before It produces excellent anaesthesia and akinesia. they enter the four rectus muscles in the posterior The onset of the block is quicker than with intraconal space. In the modern retrobulbar block, peribulbar. 23 G, 31 mm long needle, with bevel facing the Low volume of anaesthetic result in a lower globe, is inserted through the skin in the inferotem- intraorbital tension and less chemosis than with poral quadrant as far laterally as possible, just peribulbar blocks. above the junction of inferior and lateral orbital walls,seeFigure1.1,2 The atkinson’sorclassic Disadvantages insertion site, i.e. the junction of medial two-third Orbital complications: and lateral one-third of the lower orbital margin, is Optic nerve injury due to inadvertent trauma no more recommended. The reasons cited are: the from needle. needle being nearer to the globe, inferior rectus Retrobulbar haemorrhage. muscle and also closer to the neurovascular bundle Globe perforation. supplying the inferior oblique. Several cases of dip- Systemic complications: lopia owing to iatrogenic needle injury to inferior Inappropriate large dose. rectus and oblique muscles following needle enter- Accidental intravascular injection. ing at this site have been reported in literature.3,4 Intraarterial injection with retrograde flow. From the extreme corner, it is easier to stay far CSF spread within the dural cuff around the away from the globe and would prevent any optic nerve—Brain stem anaesthesia. needle injury to the inferior rectus muscle or its Other disadvantages are:

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All extraocular muscles can be paralysed by this technique except superior oblique as it is sup- plied by the trochlear nerve (IV nerve), which lie outside the muscle cone. Akinesia of the eye lids may be incomplete. A separate eye lid block, using 2.5 cc of 1% ligno- caine solution injected 0.5 cm below (lower lid) and 1.0 cm above (upper lid) the middle of the canthus, might be required.6

Modern Peribulbar block Due to several potential orbital and systemic com- plications reported with retrobulbar block, grad- ually it was replaced by a safer and equally effective peribulbar block. Figure 2: Medial peribulbar block performed The principle of this technique is to instill the with 26G 1/2 inch needle entering into the blind local anaesthetic outside the muscle cone and pit between the medial caruncle and the medial avoid proximity to the optic nerve. In the modern canthal angle. peribulbar block 23-G, 25 mm long needle is inserted as far laterally as possible in the infero- of ophthalmologist, and preference of the temporal quadrant. Once the needle is under the anaesthesiologist. globe, it is directed along the orbital floor, passing the globe equator to a depth controlled by observ- Medial Peribulbar block ing the needle/hub junction reaching the plane of 00 7 It is given using 26 G, ½ disposable needle. With the iris. After negative aspiration for blood, with the bevel facing the medial orbital wall, needle is – the globe in primary gaze, 4 5 cc of local anaes- passed into the blind pit, between the medial car- thetic agent is injected. uncle and canthus, see Figure 2. It is passed back- wards in the transverse plane, directed at 50 angle Advantages away from the sagittal plane and towards the By this procedure, all extraocular muscles includ- medial orbital wall. If the medial wall is contacted, ing superior oblique can be paralysed. the tip is slightly withdrawn and needle is redir- Thus, effective analgesia and akinesia of the ected to a depth of 15–20 mm and after negative globe. aspiration for blood, 3–5 cc of local anaesthetic The risk of local and systemic complications solution is injected.5 associated with this technique is lower. The local anaesthetic solution diffuses through Advantages the orbital septum and resulting in the paralysis Helps in the supplementation of the primary intra of orbicularis muscle. Thus, a separate eye lid or extraconal blocks. block might not be required with this technique. This extraconal space is an excellent site for administering local anaesthesia, as it communicates Disadvantages freely with the intraconal space. Also, with this injec- Onset of action is slower compared to retrobulbar tion, eyelids may fill with the anaesthetic solution technique. which provides excellent orbicularis akinesia too. More amount of LA volume might be required. Given as primary injection in patients with high Greater incidence of periorbital ecchymosis and axial length or those with posterior staphyloma.8 conjunctival chemosis can occur. Akinesia of the extraocular muscle may be less Disadvantages complete. Orbital cellulitis or abscess. Following a fractionated inferotemporal injec- Haemorrhage. tion, intraocular pressure increases significantly Globe perforation has been reported.9 and this may lead may lead to vitreous loss during intraocular surgery.7 Hence, adequate compression 2. Cannula-based injection technique of the globe either by using digits or Honan Subtenon’s block Intraocular pressure reducer should be done. It was introduced into clinical practice in the early After adequate compression, if significant 1990s as a simple, safe, effective and versatile movement of the eye still persists then supplemen- alternative to needle block.10,11 It is also known as tary injection, medial peribulbar block is adminis- parabulbar, pinpoint anaesthesia12 or episcleral tered. The administration of this supplementary block.13 Local anaesthetic eye drops are instilled injection depends upon the type and duration onto the conjunctiva. Under sterile conditions, at of the procedure to be performed, the experience the inferonasal quadrant, 3–5 mm away from the

Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | 25 Major review

limbus, the conjunctiva and Tenon capsule are ciliary body and thereby relieves discomfort experi- gripped with non-toothed forceps and a small enced during intraocular lens placement. incision is made through these layers with Westcott scissors to expose the sclera. A blunt Advantages curved posterior sub-Tenon’s cannula mounted on It avoids the systemic and local complications to a 5 ml syringe with local anaesthetic is inserted associated with eye blocks. through the hole along the curvature of the sclera. No fear or pain of injection of the needle. Injection of local anaesthetic agent under the Rapid visual rehabilitation occurs just after the Tenon capsule blocks the sensation from the eye procedure. by action on the short ciliary nerves as they pass through the Tenon capsule to the globe. Akinesia Disadvantages is obtained by direct blockade of anterior motor Apart from surgical skill, the patient should be nerve fibres as they enter the extraocular muscles. cooperative enough for successful completion of Two percentage lidocaine is the most commonly eye surgery under topical anaesthesia. used local anaesthetic agent.14 Not suited for patients who are young, anxious, patients who display a marked squeezing Advantages or muscular spasm during tonometry or indirect Simple, safe and effective alternative technique to ophthalmoscopy. needle block. Not a technique of choice in patients with small It is well tolerated by patients. pupils, very dense cataract, complicated cataract, etc. Can be used safely in patients on anticoagu- Retained visual sensations that include seeing lants, those with high myopic eyes, etc. light, colours, movements and instruments during Very minimal chance for optic nerve getting surgery are expected to occur more frequently injured especially when smaller volumes of LA is under topical anaesthesia because optic nerve injected anteriorly. function is not affected. Although majority of patients feel comfortable with visual sensations Disadvantages they experience, a small proportion find the Requires surgical skills. experience unpleasant or frightening.22 Chemosis and sub-conjunctival haemorrhage Preoperative counselling and IV Midazolam are can hinder the surgical field, it can also stimulate known to alleviate the fear caused by intraopera- postoperative scarring later.5 tive visual images seen.23 Not a suitable technique in patients who had multiple surgeries owing to scarring. General anaesthesia Leakage of local anaesthetic solution from the General anaesthesia provides excellent anaesthesia, injection site which decreases the effectiveness of analgesia and akinesia. In addition, the duration of the block. anaesthesia can be varied to accommodate the Akinesia is variable and volume dependent. length of surgery. Modern health care, where time Orbital and retrobulbar haemorrhage, globe per- and cost efficiency are significant factors, renders foration, the central spread of local anaesthetic and general anaesthesia unlikely for the bulk of cataract orbital cellulitis have been reported to occur.15–17 surgeries. But still there are some absolute and rela- tive indications for administering it. Non-akinetic Technique Topical anaesthesia Absolute indications It can be achieved either by instilling local anaes- Patient refusal to regional anaesthesia. thetic eye drops (0.5% Proparacaine Hydochloride Mentally retarded patients. or 2–4% lignocaine)18 or application of lignocaine Local infection. gel19 and found to be useful for cataract, glaucoma Paediatric patients. surgery like trabeculectomy20 and secondary Allergy to local anaesthetic agents. intraocular lens implantation. Topical anaesthetic agents block trigeminal nerve endings in the Relative indications cornea and conjunctiva, leaving the intraocular Younger adults. structures in the anterior segment unanaesthetized. Patients on anticoagulants. Thus, manipulation of the iris and stretching of the Very anxious patients. ciliary and zonular tissues during surgery can irri- Inability to lie flat. tate the ciliary nerves, resulting in discomfort. A High myopia. modified technique consists of combining topical Prolonged complex surgeries. anaesthesia with 0.5 ml of 1% lignocaine (preser- Uncontrolled neurological movements. vative free) injected through the side port incision High myopia. after evacuation of aqueous (intracameral anaesthe- Allergy. sia).21 It provides sensory blockage of the iris and Nystagmus.

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Choosing anaesthesia for cataract surgery 3. Gomez-Arnau JI, Yanguela J, Gonzalez A, Andres Y, Garcia del Given the choices for ocular anaesthesia no single Valle S, Gili P. Anaesthesia-related diplopia after cataract – mode of anaesthesia can serve as a universal surgery. Br J Anaesth 2003;90(2):189 93. 4. Taylor G, Devys JM, Heran F, Plaud B. Early exploration of choice for all patients and all surgeons. For the diplopia with magnetic resonance imaging after peribulbar same patient, different surgeons may select differ- anaesthesia. Br J Anaesth 2004;92:899–901. ent techniques of anaesthesia. The skill and 5. Kumar CM, Dodds C. Ophthalmic regional blocks: review experience of surgeon, cooperation of patient, article. Ann Acad Med Singapore 2006;35:158–67. type of cataract, associated ocular comorbidity 6. Franz Schimek, Manfred Fahle. Techniques of facial nerve – like corneal opacity, pupillary dilatation, etc. are block. Br J Ophthalmol 1995;79:166 73. 7. Hamilton RC. Techniques of orbital regional anaesthesia. Br J important factors while deciding upon the type of Anaesth 1995;75:88–92. anaesthesia. It is essential that the surgeon, 8. Vohra SB, Good PA. Altered globe dimensions of axial myopia patient and anaesthesiologist work together and as risk factor for penetrating ocular injury during peribulbar be involved in the selection and execution of anaesthesia. Br J Anaesth 2000;85(2):242–5. anaesthesia during the surgery. The ideal surgery 9. Ball JL, Woon WH, Smith S. Globe perforation by the second is conducted under the safest conditions, is cost peribulbar injection. Eye 2002;16:663–5.. and time efficient and ultimately results in excel- 10. Stephen J Mather, Kong KL, Shashi B Vohra. Loco-regional anaesthesia for ocular surgery. Anticoagulant and antiplatelet lent outcomes as well as patient satisfaction. drugs. Curr Anaesth Crit Care 2010;21(4):158–63. These are our goals with regard to the use of 11. Hansen EA, Mein CE, Mazzoli R. Ocular anesthesia for cataract anaesthesia for cataract surgery. surgery: a direct sub-Tenon’s approach. Ophthalmic Surg As mentioned above, general anaesthesia for 1990;21:696–9. cataract has its own indications both absolute and 12. Fukasaku H, Marron JA. Sub-Tenon’s pinpoint anesthesia. J relative. With regard to regional anaesthesia, Cataract Refract Surg 1994;20:468–71. retrobulbar block owing to potential orbital and 13. Ripart J, Metge L, Prat-pradal D, Lopez FM, Eledjam JJ. Medial canthus single-injection episcleral (sub-tenon anesthesia): systemic complications has become almost obso- computed tomography imaging. Anesth Analg 1998;87:42–5. lete in clinical practice. Peribulbar anaesthesia is 14. Mclure HA, Rubin AP. Review of local anaesthetic agents. thought to decrease the likelihood of optic nerve Minerva Anesthesiol 2005;71:59–74. and globe perforation while maintaining the desir- 15. Rahman I, Ataullah S. Retrobulbar hemorrhage after able qualities of excellent akinesia and analgesia. sub-Tenon’s anesthesia. J Cataract Refract Surg – However, the higher volume of injectate required 2004;30:2636 7. 16. Ruschen H, Bremner FD, Carr C. Complications after and longer duration of onset may make it a less ’ – ’ sub-Tenon s eye block. Anesth Anal 2003;96:273 7. attractive alternative. Sub-tenon s injections with 17. Lip PL. Postoperative infection and subtenon anaesthesia. Eye blunt cannula have an even lower risk of local 2004;18:229. complications. With all orbital regional blocks, 18. Martini E, Cavallini GM, Campi L, Lugli N, Neri G, Molinari P. cosmetic complications such as localized swelling, Lidocaine versus ropivacaine for topical anaesthesia in cataract bruising and sub-conjunctival haemorrhage may surgery. J Cataract Refract Surg 2002;28:1018–22. fi lead to reduced patient satisfaction. In addition, 19. Koch PS. Ef cacy of 2% lidocaine jelly as a topical agent in cataract surgery. J Cataract Refract Surg 1999;25:632–4. eye movement and vision are affected for some 20. Zabriskie NA, Ahmed IIK, Crandell AS, Daines B, Burns TA, time after surgery. Patel BCK. A comparison of topical and retrobulbar anesthesia Topical anaesthesia is the most cost and time for trabeculectomy. J Glaucoma 2002;11:306–14. efficient. It does not affect vision or motility, so 21. Martin RG, Miller JD, Cox CC, Ferrel SC, Raanan MG. Safety patients may have improved and useful vision and efficacy of intracameral injections of unpreserved lidocaine almost immediately after surgery. There are also to reduce intraocular sensations. J Cataract Refract Surg – minimal cosmetic changes. Though it provides a 1998;24:961 3. 22. Colin SH Tan, Au Eong, Chandra M Kumar, least controlled environment for performing cata- Venkatesh Rengaraj, Muralikrishnan Radhakrishnan. Fear from ract surgery, with careful patient selection and visual experiences during cataract surgery. Ophthalmologica appropriate counselling and with intravenous sed- 2005;19:416. ation, it may ultimately be the safest mode of 23. Jaichandran V. Venkatakrishnan, Chandra M. Kumar, anaesthesia. For many patients and surgeons this Vineet Ratra, Jagadeesh Viswanathan, Vijay A. Jeyaraman, mode of anaesthesia fulfils most of the goals of Thennarasu Ragavendera. Effect of sedation on visual anaesthesia in cataract surgery.24 sensations in patients undergoing cataract surgery under topical anaesthesia: a prospective randomized masked trial. Acta Ophthalmol [Epub ahead of print] [last accessed on 8 Nov References 2012]. — 1. Gary L. Fanning. Orbital regional anesthesia ocular 24. Joselito S. Navaleza, Sagun J. Pendse, Mark H. Blecher. Orbital – anaesthesia. Ophthalmol Clin N Am 2006;19:221 32. Regional Anesthesia- Ocular anaesthesia. Ophthalmol Clin N 2. Kumar CM, Dowd TC. Complications of ophthalmic regional Am 2006;19:233–7. blocks: their treatment and prevention. Ophthalmologica 2006;220(2):73–82.

How to cite this article Pradyna S. Choosing the Type of Anaesthesia for Cataract Surgery, Sci J Med & Vis Res Foun 2015;XXXIII:24–27.

Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | 27 Tips & tricks Managing Awake Patients under the Drapes

Shobha Ravishankar

Anaesthesiologist, Introduction respond purposefully following repeated or Sankara Netralaya, Most of the eye surgeries in adults are done under painful stimulation. Chennai, India local anaesthesia. Generally with careful selection The ability to independently maintain ventila- and explanation, most of them accept it. However, tory function may be impaired. Correspondence to: there always remain a proportion of patients who Patients may require assistance in maintaining Shobha Ravishankar, might benefit from sedation. Sedation is a very a patent airway, and spontaneous ventilation may Anaesthesiologist, useful adjunct for the success of eye surgery be inadequate. Sankara Netralaya, under local anaesthesia. The ideal sedative for Cardiovascular function is usually maintained. Chennai, India ophthalmic procedures performed under local It is generally advised to avoid deep sedation in Email: anaesthesia should have a rapid onset and short ophthalmic surgeries since the patients face will duration of action to ensure rapid awakening and be covered with the drapes during surgery. early discharge from hospital, especially in the General anaesthesia should be considered in such setting of day surgery. Also, the agent should be cases. non-toxic, non-accumulating and have predict- able effects and should be cheaper. In this Role of sedation in eye surgery chapter, we will discuss the importance of sed- The patients posted for eye surgery are generally ation in eye surgery, the different sedative agents worried and anxious about their visual prognosis used, monitoring standards and complications following surgery. Apart from this, these patients involved in administration of sedation. would be much concerned about the pain asso- ciated with administration of local anaesthetic What is Sedation? solution using needle blocks. Pain, fear and The American Society of Anaesthesiologists policy anxiety are major predictors of lower patient satis- 2 statement on Continuum of Depth of Sedation.1 faction with ocular surgery. Moreover, such affective components can complicate surgery on Minimal sedation (Anxiolysis) two levels. The intraoperative cooperativeness of Drug-induced state during which patients respond the patients may be reduced, thereby increasing normally to verbal commands. the risk of complications and making the continu- fi Cognitive function and coordination may be ation of surgery technically dif cult. More import- impaired, but ventilatory and cardiovascular func- antly, they may cause an exaggerated tions are unaffected. neuroendocrine stress response. It is well estab- lished that sympathetic surges can lead to hyper- tension, tachycardia, ischaemic strain on the Indications heart, hyperventilation and acute panic attacks. Anterior segment surgeries which are of shorter These effects are particularly detrimental in duration like surgery for cataract, glaucoma, etc. elderly patients with multiple co morbidities and lower physiological reserves.3 Allaying undue Moderate sedation/Analgesia (Conscious anxiety in these patients not only tends to Sedation) improves patient’s satisfaction level towards Drug-induced depression of consciousness during surgery but also prevents any untoward complica- which patients respond purposefully to verbal tions occurring during the course of surgery. commands, either alone or accompanied by light Although proper preoperative counselling and tactile stimulation. reassurance is known to reduce anxiety, in No interventions are required to maintain a selected patients conscious sedation is indicated to patent airway, and spontaneous ventilation is reduce discomfort during block administration adequate. and surgery with added advantages of haemo- Cardiovascular function is usually maintained. dynamic stability together with enhanced patient cooperation and satisfaction.4 Indications In addition to physical pain from administra- Posterior segment surgeries like vitreoretinal tion of local anaesthesia and surgery, frightening surgery, oculoplastic cases and strabismus surgery. visual sensations/images can be perceived by patients (3–16.1%) during phacoemulsification Deep sedation/Analgesia cataract and other ophthalmic surgical proce- Drug-induced depression of consciousness during dures.5–7 The retained visual sensations are which patients cannot be easily aroused but expected to occur more frequently under topical

28 Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | Tips & tricks anaesthesia because optic nerve function is not extensively used as a sedative agent for ophthal- affected. In an earlier study, 15.4% of patients are mic procedures due to its favourable pharmacoki- known to have experienced fear due to these netic properties. It has a distribution half-life of visual sensations under topical anaesthesia.6 2–8 min after intravenous administration and a Many authorities advocate preoperative counsel- short elimination half-life of 30–60 min. The ling for alleviating fear caused by intra-operative onset of anaesthesia occurs within 30 s of the end visual images/sensations.7–9 A recent survey has of bolus infusion with the effect lasting 3–10 min, confirmed that although many ophthalmologists subject to dose and rate of infusion.16 Rapid hyp- have become aware of the phenomenon of nosis and short duration of action with earlier intra-operative visual experience still many do not patient recovery, which is especially important for counsel their patients.10 Thus, the other method ophthalmic day surgery.17 Propofol has well- by perception of visual sensations by patients can established anti-emetic properties18 and is be reduced is by administration of sedation. reported to lower IOP intraoperatively.19 Increased Sedation with intravenous midazolam 0.015 mg/ IOP during surgery is common and may make the kg reduces the ability to see and recall operation more technically difficult, hence intra-operative visual images/sensations in increasing complication rates. Neel et al.20 exam- patients undergoing phacoemulsification cataract ined the effects on IOP, pulse rate and BP of surgery under topical anaesthesia. Patients sedated low-dose intravenous sedation with propofol. It with midazolam experienced less disturbances to was found that propofol caused a 17–27% the light emanating from the microscope. We decrease in IOP compared with the baseline, with believe reduction of these unpleasant experiences the effect taking place within the first minute and can only improve patient’s satisfaction.11 persistent even after 7 min. However, such IOP Administration of sedation in an eye surgeries lowering effects are not unique to propofol; they depends upon various factors like patient’s age are likely due to relaxation of the extraocular and systemic co-morbidities, type of surgical pro- muscles rather than the sedative agents cedure, mode of anaesthesia, surgeon’s preference, themselves.16 etc. Respiratory depression and reduced BP are major side effects of propofol. However, it has Sedative agents used been suggested that propofol may still be safely Benzodiazepines administered if given at a lower dose. Other side In general, benzodiazepines can be administered effects of propofol include pain on injection,16 via oral and parenteral routes. Diazepam, midazo- increased oculocardiac reflex,21 anaphylaxis, lam and lorazepam are commonly used for sed- patient movement22 and sneezing.23 The lipid- ation in ophthalmic procedures. Of these based formulation of propofol also supports rapid Midazolam is widely used all over in clinical prac- microbial growth at room temperature. tice. Midazolam has both amnesic and anxiolytic Extrinsically contaminated propofol has been properties, lack of venous irritation and rapid associated with postoperative endogenous Candida patient recovery. It is given slowly intravenously albicans endophthalmitis or fungemia.24,25 Strict in 1 mg increments, or 0.015 mg/kg. It takes aseptic preparation and administration of propofol nearly 5–10 min to act. In patients over 60 years are therefore crucial for the prevention of such and above, it is advisable to reduce the dose by infections. 30%. It can result in respiratory depression or arrest that is more pronounced in the elderly, alco- Opioids and narcotic analgesics holics or when used in combination with other Fentanyl citrate sedative agents. Caution also needs to be taken in Narcotic analgesic that has been extensively used patients with cardiac, renal or hepatic impairment. in ophthalmic procedures under local anaesthesia; Midazolam prevents the increase in blood pressure these procedures include cataract surgery26 and (BP) associated with insertion of the peribulbar the repair of open-globe eye injuries.27 It has a block.12 It is commonly used either individually or rapid onset of action and a short duration of in combination with other agents during a variety action, about 30 min after a single dose with a of ophthalmic procedures from cataract surgery20 half-life of 2–7 h. Given in a bolus dose of 25–50 to oculoplastic21 and vitreoretinal procedures.22 mcg, it provides analgesia with minimal sedation. Another advantage is that they are the only class Other opioids which are reported to be used for of sedative hypnotic whose activity can be readily ophthalmic surgeries are Remifentanil, Alfentanil reversed by an antagonist (flumazenil). and sufentanil. The role of remifentanil in sed- ation under oph ophthalmic anaesthesia has been Intravenous anaesthetic induction agents documented in previous studies. Remifentanil was Propofol found to be superior to propofol when used as the Propofol 2,6-diisopropylphenol is an important sole sedative agent during combined peribulbar intravenous anaesthetic agent that has been and retrobulbar block for cataract surgery.

Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | 29 Tips & tricks

Furthermore, respiratory depression with remifen- a high level of monitoring for sedated patients is tanil was mild and not clinically significant.23 always recommended good clinical practice.

α-adrenoreceptor agonists References Dexmedetomidine is a selective α2-adrenoreceptor 1. ASA Committee on Quality Management and Departmental agonist that has been used for sedation in oph- Administration (Continuum of depth of sedation, definition of thalmic surgery, and its role is still expanding. general anesthesia and levels of sedation/ analgesia (approved Dexmedetomidine has anxiolytic, sedative and by ASA house of delegates on 13 October 1999, amended on 27 analgesic properties Dexmedetomidine has been October 2004). used for sedation in cataract surgery under local 2. Fung D, Cohen MM, Stewart S, Davies A. What determines anaesthesia28,29 and also as a supplement to patient satisfaction with cataract care under topical local 30 anesthesia and monitored sedation in a community hospital general anaesthesia in vitreoretinal surgery. A – μ setting? Anesth Analg 2005;100:1644 50. lower-dose intravenous regime of 0.5 g/kg/h dex- 3. Tan CS, Rengaraj V, Au Eong KG. Visual experiences of cataract medetomidine for 10 min followed by 0.2 μg/kg/h surgery. J Cataract Refract Surg 2003;29:1453–4. for 50 min was also found to be effective for pro- 4. Kumar CM, Dodds C. Ophthalmic regional block. Ann Acad viding sedation and safe in terms of BP and heart Med Singapore 2006;35:158–67. rate control.31 5. Au Eong KG, Lee HM, Lim ATH, Voon LW, Yong VSH. Subjective visual experience during extracapsular cataract extraction and intraocular lens implantation under retrobulbar Monitoring during sedation anaesthesia. Eye 1999;13:325–8. The level of monitoring for sedation during oph- 6. Au Eong KG, Low CH, Heng WJ, Aung T, Lim TH, Ho SH, thalmic local anaesthesia should be similar to that Yong VS. Subjective visual experience during during general anaesthesia. All patients should phacoemulsification and intraocular lens implantation under receive oxygen at a flow of 2–4 l/min via nasal topical anaesthesia. Ophthalmology 2000;107:248–50. cannula placed near both the nostrils. Monitoring 7. Wickremasinghe SS, Tranos PG, Sinclair N, Andreou PS, Harris ML, Little BC. Visual perception during includes: phacoemulsification cataract surgery under subtenon’s • Pulse oximetry, anaesthesia. Eye 2003;17:501–5. 8. Kuang Hu, Stephen Scotcher. Seen from the other side: visual • Electrocardiography, experiences during cataract surgery under topical anaesthesia. BMJ 2005;331:1511. • Non-invasive BP. 9. Au Eong KG. Visual Experience during cataract surgery. Ann Acad Med Singapore 2003;31:666–74. 10. Seo-Wei Leo, Llewellyn Kuan-Ming Lee, Kah-Guan Au Eong. Complications of Sedation Visual experience during phacoemulsification under topical Complications of intravenous sedation are local, anaesthesia: a nationwide survey of Singapore systemic and other non-medical adverse events. ophthalmologists. Clin Exp Ophthalmol 2005;33: 578–81. Local complications: Failed cannulation, hema- 11. Jaichandran V. Venkatakrishnan, Chandra M. Kumar, toma, phlebitis, pain, air embolism and inadvert- Vineet Ratra, Jagadeesh Viswanathan, Vijay A. Jeyaraman, ent intra-arterial injection, other issues of deep Thennarasu Ragavendera. Effect of sedation on visual sensations in patients undergoing cataract surgery under topical sedation and adverse medical events may also anaesthesia: a prospective randomized masked trial. Acta arise. Ophthalmol [Epub ahead of print] [last accessed on 8 November Systemic complications: Overdose can be asso- 2012]. ciated with cardiovascular and central nervous 12. Pac-Soo CK, Deacock S, Lockwood G, Carr C, Whitwam JG. system depression thereby leading to hypoventila- Patient controlled sedation for cataract surgery using peribulbar – tion, hypercapnia and airway obstruction. block. Br J Anaesth 1996;77:370 4. 13. Habib NE, Mandour NM, Balmer HG. Effect of midazolam on Other adverse non-medical events: Oversedation anxiety level and pain perception in cataract surgery with can also lead to restlessness, and unexpected or topical anesthesia. J Cataract Refract Surg 2004;30:437–43. unwanted movements during surgery. The loss of 14. Biswas S, Bhatnagar M, Rhatigan M, Kincey J, Slater R, residual cooperation is especially prominent in Leatherbarrow B. Low-dose midazolam infusion for oculoplastic dementia patients even with small doses of surgery under local anesthesia. Eye 1999;13:537–40. sedation. 15. Morley HR, Karagiannis A, Schultz DJ, Walker JC, Newland HS. Sedation for vitreoretinal surgery: a comparison of anaesthetist-administered midazolam and patient-controlled Conclusions sedation with propofol. Anaesth Intensive Care 2000;28:37–42. Adequate sedation in patients under going oph- 16. Loots H, Wiseman R. Agents for sedation in ophthalmic thalmic surgery under local anaesthesia improves surgery: a review of the pharmacodynamics and clinical patient’s satisfaction, makes them more coopera- applications. Curr Anaesth Crit Care 2006;17:179–90. tive and helps the surgeon to complete the surgery 17. Ferrari LR, Donlon JV. A comparison of propofol, midazolam, uneventfully. Sedation should be individualized and methohexital for sedation during retrobulbar and peribulbar block. J Clin Anesth 1992;4:93. according to the patient, the type of surgery and ’ ‘ ’ 18. Reimer EJ, Montgomery CJ, Bevan JC, Merrick PM, surgeon s preferences. There are no ideal drugs Blackstock D, Popovic V. Propofol anaesthesia reduces early for sedation for cataract surgery; a good knowl- postoperative emesis after paediatric strabismus surgery. Can J edge of the pharmacology of sedative agents and Anaesth 1993;40:927–33.

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19. Coley S, Jones GW, Lassey D, May AE, Fell D. A comparison of 25. Daily MJ, Dickey JB, Packo KH. Endogenous Candida the effects of alfentanil/droperidol or fentanyl/droperidol on endophthalmitis after intravenous anesthesia with propofol. intra-ocular pressure. Anaesthesia 1990;45:477–80. Arch Ophthalmol 1991;109:1081–4. 20. Neel S, Deitch R Jr, Moorthy SS, Dierdorf S, Yee R. Changes in 26. Balkan BK, Iyilikçi L, Günenç F, Uzümlü H, Kara HC, Celik L, intraocular pressure during low dose intravenous sedation with et al Comparison of sedation requirements for cataract surgery propofol before cataract surgery. Br J Ophthalmol under topical anesthesia or retrobulbar block. Eur J Ophthalmol 1995;79:1093–7. 2004;14:473–7. 21. Hahnenkamp K, Hönemann CW, Fischer LG, Durieux ME, 27. Boscia F, La Tegola MG, Columbo G, Alessio G, Sborgia C. Muehlendyck H, Braun U. Effect of different anaesthetic regimes Combined topical anesthesia and sedation for open-globe on the oculocardiac reflex during paediatric strabismus surgery. injuries in selected patients. Ophthalmology 2003;110:1555–9. Paediatr Anaesth 2000;10:601–8. 28. Virkkilä M, Ali-Melkkilä T, Kanto J, Turunen J, Scheinin H. 22. Vann MA, Ogunnaike BO, Joshi GP. Sedation and anesthesia Dexmedetomidine as intramuscular premedication in care for ophthalmologic surgery during local/regional out-patient cataract surgery. A placebo-controlled dose-ranging anesthesia. Anesthesiology 2007;107:502–8. study. Anaesthesia 1993;48:482–7. 23. Boezaart AP, Berry RA, Nell ML, van Dyk AL. A comparison of 29. Virkkilä M, Ali-Melkkilä T, Kanto J, Turunen J, Scheinin H. propofol and remifentanil for sedation and limitation of Dexmedetomidine as intramuscular premedication for daycase movement during periretrobulbar block. J Clin Anesth cataract surgery. A comparative study of dexmedetomidine, 2001;13:422–6. midazolam and placebo. Anaesthesia 1994;49:853–8. 24. McNeil MM, Lasker BA, Lott TJ, Jarvis WR. Postsurgical 30. Lee YY, Wong SM, Hung CT. Dexmedetomidine infusion as a Candida albicans infections associated with an extrinsically supplement to isoflurane anaesthesia for vitreoretinal surgery. contaminated intravenous anesthetic agent. J Clin Microbiol Br J Anaesth 2007;98:477–83. 1999;37:398–403. 31. Abdalla MI, Al Mansouri F, Bener A. Dexmedetomidine during local anesthesia. J Anesth 2006;20:54–6.

How to cite this article Shobha R. Managing Awake Patients under the Drapes, Sci J Med & Vis Res Foun 2015; XXXIII:28–31.

Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | 31 Short review Systemic and Ophthalmic Complications Following Regional Block

Sujatha Vittal

Consultant Anaesthesiologist, Ophthalmic surgery is particularly suited to • Presents as markedly blood stained chemo- Sankara Nethralaya, regional anaesthesia. In recent years, topical sis and do not ordinarily threaten vision.4 Chennai, India anaesthesia has become a common modality of Treatment anaesthesia for cataract surgery. However, orbital Correspondence to: regional anaesthesia is still preferred by many • Intermittent digital pressure with a gauze Sujatha Vittal, ophthalmologists for cataract surgery and pad over the closed lids is required to Consultant Anaesthesiologist, according to recent studies many patients too reduce the raised IOP, if it occurs. Sankara Nethralaya, prefer it.1,2 Each technique has its own risk/ Chennai, India benefitprofile. Although serious life or vision Arterial haemorrhage Email: [email protected] threatening complications like brain stem anaes- It can be more serious. thesia, retrobulbar haemorrhage and globe per- Signs and Symptoms foration, are reported rarely, they can occur • Proptosis, tight eye lids, ecchymosis, lid either due to local agents used or improper swelling and a dramatic increase in intrao- administration of regional block. To prevent such 4,5 cular pressure. complications to occur a thorough knowledge of the anatomy of orbit and its contents and under- • ·A compressive retrobulbar haematoma may standing the pharmacodynamics/pharmacokinet- threaten retinal perfusion by causing ics of the agents used is of vital importance. central retinal artery occlusion.4 These two factors are already dealt by other Treatment authors in this book, We will now focus on various complications their aetiology, risk • Firm digital pressure usually stops the factors, methods to prevent and treat them bleeding. Most retrobulbar haemorrhage accordingly. can be successfully treated conservatively.5

Complications • The surgeon has to evaluate the extent of Complications following regional blocks can be the haemorrhage and determine whether either Orbit or Systemic related. further interventions are necessary. • · IOP can be lowered with acetazolamide or Orbital complications intravenous mannitol.5 Conjunctival oedema (chemosis) and sub- conjunctival haemorrhage (ecchymosis) • Rarely, immediate lateral canthotomy or even paracentesis might be required to 4 • More common with peribulbar block due to relieve orbital pressure. anterior spread of local anaesthetic (LA) Globe damage agent. Globe penetration • These minor complications usually resolve Has only wound of entry. spontaneously within few hours and do not interfere with surgery.3 Globe perforation Double puncture wounds (wound of entry and Prevention exit). Risk factors • Decreasing the rate of injection. • · Patients with axial length > 26 mm.1,5 • Adequate digital massage of the globe fol- • lowing injection. A deep set eye. • Multiple injections. Retrobulbar haemorrhage • Caused by needle penetration of either the venous Previous sclera buckling. or arterial vessels in the orbit. • Lack of orbital knowledge or technique.6–8

Venous haemorrhage Signs and symptoms • Slow in onset. • Intense ocular pain.

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• Sudden loss of vision. • Use of high concentrations of Lidocaine.8,10 • Hypotonus. • This is most commonly seen if classical one-third/two-third approach to both peri- Prevention bulbar and retrobulbar block is used • Insertion of the needle based on anatomical because this usually penetrates the inferior principles. rectus muscle. • Explain the procedure and motivate Management patients to co-operate while performing • Often resolve spontaneously but if perman- blocks. ent may require strabismus surgery. • Prefer peribulbar rather than retrobulbar Corneal abrasions block. This can occur from a compression device or post- • Using a needle of maximum length 25 mm. operatively as the motor effects wear off, allowing the eyelid to open, thus exposing an anaesthetic • Awareness that ocular and orbital anatomy cornea. When the lid function is impaired oper- may be disturbed by pre-existing ocular ated eye should be patched until sensation and pathology and surgery. motor functions return. Management Ocular explosion • Surgery is deferred, ophthalmoscope exam- ination or ultrasound is performed and • Inadvertent injection of LA solution dir- patient is referred to retinal surgeon. ectly into the globe under high pressure until the globe ruptures or explodes.11,12 Amaurosis • Peribulbar injections of LA do not lead to tempor- It is a devastating injury that may go ary loss of vision, whereas retrobulbar injection unrecognized. causes this as a consequence of the optic nerve Prevention becoming blocked.3,9 Before surgery patients should be warned and • Careful use of a syringe 10 mL with a blunt counselled for this temporary phenomenon to needle. allay undue anxiety and panic attacks during • Discontinue injection if resistance is met. surgery. • Inspecting the globe prior to ocular Optic nerve injury massage or placement of a Honan Result from balloon.11 • Direct needle stick injury to the optic nerve. Treatment • Secondary to haemorrhage within or • When ocular explosion occurs, immediate around the optic nerve. referral to and intervention by a vitreoret- inal surgeon is optimal. • Pressure necrosis from LA agent.4 Practicing ophthalmologists should be aware of Signs and symptoms this blinding but preventable complication of • Partial or complete loss of vision can occur. ocular surgery.

Risk factors Systemic complications • In smaller orbits. LA solution toxicity and vasovagal reactions are the most common systemic complications asso- • Placement of a long needle aiming towards ciated with local anaesthesia. Systemic complica- the apex while performing blocks. tions can range anywhere between a mild vasovagal attack to a life threatening emergency. Myotoxicity Causes of LA toxicity Damage to the extraocular muscles from orbital blocks can result in strabismus, ptosis and • Inadvertent intra-vascular injection, entropion. • Brain stem anaesthesia, Possible mechanisms • Excessive dose of anaesthetic, • Direct needle trauma. • Allergic reaction, • Ischaemic pressure necrosis caused by a large volume of LA. • Vasovagal reaction.

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Patterns of LA toxicity • Oral chlorpheniramine Tablet. Neurological leading to cardiovascular collapse Brain stem anaesthesia • Numbness of tongue and circum-oral area It occurs when the injected anaesthetic gains entry into the subarachnoid space. The proposed • Lightheadedness mechanism is that the cerebral dura mater pro- • Visual disturbances vides a dural sheath for the optic nerve as it passes through the optic foramen. This sheath • Muscular twitching fuses with the epineurium of the optic nerve and • Unconsciousness is continuous with the sclera, providing a poten- tial conduit for LA to pass subdurally into the • Convulsions brain. • Coma Time of onset of symptoms • Respiratory arrest • Variable, • Cardiovascular arrest • But major sequelae develop usually in the first 15 min after the injection. Allergic reactions Allergic reactions from amide anaesthetics such as Signs and symptoms lidocaine and bupivacaine are rare. • Vary, depending upon which part of the 17–19 Hyaluronidase allergy CNS is affected by the LA Hyaluronidase, an additive used to promote the • Intense shivering onset and quality of the block, may occasionally cause allergic reactions. • Vomiting Signs and symptoms • Temporary hemiplegia Swelling of the same11–15 and contralateral16 orbital region owing to hyaluronidase allergy • Aphasia following regional block have been reported • Contralateral cranial nerve palsy previously. • Generalized convulsions Time of onset Variable • Blockade of the 8 to 12th cranial nerves will result in deafness, tinnitus, vertigo, • – Immediate (pre-operative or dysarthria, dysphagia and aphasia20 23 intra-operative),16 These signs may present themselves in various • Early (within a few hours), combinations and the anaesthesiologist must be • Intermediate (within a few days), alert and prepared to provide cardiopulmonary resuscitation as an emergency, when there are • 11,12 Late (within weeks). apparent signs of local anaesthesia spreading to Differential diagnosis the CNS. While symptomatic and proper treatment Although uncommon, allergy to hyaluronidase can lead to total recovery of the patient, delay in injected during ophthalmic blocks should be con- diagnosing and treating could be fatal. sidered in a differential diagnosis of patients who present with acute post-operative orbital swelling Oculocardiac reflex and inflammation. In the absence of septic foci of Mechanism of action infection, fever, altered blood count, etc. allergic Mechanical stimulation of the globe response to LA and adjuvants used should be suspected. Afferent pathway is via the ciliary nerves to the ciliary ganglion, then via the ophthalmic branch Diagnosis of the trigeminal nerve to the brain. • Many of these patients gives history of The efferent pathway is via the vagus to the heart. exposure to agent (Hyaluronidase) suggest- ing it is due to Type I IgE mediated hyper- Manifests as bradycardia, hypotension or sensitivity reaction. cardiac arrthymias. Can be encountered in • Intradermal test can further confirm the diagnosis. • Squint surgery in paediatric age group Management • During intraorbital injection of LAs • Systemic steroids. • Following digital massage to the eye

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• Pinching of the conjunctiva with a forceps ✓ Injection at superomedial quadrant should not • Postoperative pressure of the bandage24 be administered. Superomedial quadrant is more vascular in nature when compared with the Prevention remaining other three quadrants resulting in more chances of haemorrhage to occur in the lid • Monitor ECG, pulse oximetry while per- and as the globe is closer to the roof than to the forming regional block floor, superomedial block per se can result in 25 • During surgery gentle manipulation of perforation of the globe. extraocular muscles to be given ✓ Once the local anaesthetic has been injected the most important thing do be done immediately is Management the gentle digital ocular massage for a period of • Removal of the inciting stimulus is immedi- 2 min. ately indicated ✓ Always assess the initial block and if required • If bradycardia still persists or recurrs, then perform supplementary injections. Inj atropine or glycopyrrolate IV to be administered

Vasovagal reaction References This is a neurocardiogenic syncope. An abnormal 1. Kumar CM. Orbital regional anesthesia: complications and their autonomic response with vasodilatation and prevention. Indian J Ophthalmol 2006;54:77–84. increased vagal tone. There may also be a reduc- 2. Friedman DS, Reeves SW, Bass EB, Lubomski LH, Fleisher LA, tion in cardiac filling and bradycardia. Schein OD. Patient preferences for anaesthesia management during cataract surgery. Br J Ophthalmol 2004;88:333–5. 3. Davis DB II, Mandel MR. Efficacy and complication rate of 16,224 consecutive peribulbar blocks. A prospective multicenter Conclusion study. J Cataract Refr Surg 1994;20:327–37. Ophthalmic regional anaesthesia has evolved into 4. Troll GF. Regional ophthalmic anesthesia: safe technique and avoidance of complications. J Clin Anesth 1995;7:163–72. a sophisticated art which requires a sound knowl- 5. Taylor G, Devys JM, Heran F, Plaud B. Early exploration of edge of orbital anatomy, physiology and pharma- diplopia with magnetic resonance imaging after peribulbar cology of ophthalmic drugs. The technique is not anaesthesia. Br J Anaesth 2004;92:899–901. without complication. It is a must that adequate 6. Levin ML, O’Connor PS. Visual acuity after retrobulbar training under expert supervision is a prerequisite anesthesia. Ann Ophthalmol 1989;11:337–9. before attempting to perform regional block. Both 7. Hamilton RC. A discourse on the complications of retrobulbar – ophthalmologists and ophthalmic anaesthesiolo- and peribulbar blockade. Can J Ophthalmol 2000;35:363 72. 8. Wong DH. Review article. Regional anaesthesia for intraocular gists must be prepared to deal with rare, but surgery. Can J Anaesth 1993;40:635–57. serious complications that can occur with any 9. Arora R, Verma L, Kumar , Kunte R. Regional anaesthesia technique of orbital regional anaesthesia. and optic nerve conduction. J Cataract Refr Surg 1991:17:506–8. 10. Hamed LM. Strabismus presenting after cataract surgery. Opthalmology 1991:98:247–52. Clinical Practical Pearls to be remembered 11. Bullock JD, Warwar RE, Green WR. Ocular explosion during cataract surgery: a clinical, histopathological, experimental, and biophysical study. Trans Amer Ophthalmol Soc 1998;96:243–76. ✓ Bevel should face the globe, to reduce the 12. Ahluwalia HS, Lukaris A, Lane CM. Delayed allergic reaction to chance of snagging of the globe by the tip of the hyaluronidase: a rare sequel to cataract surgery. Eye needle. 2003;17:263–6. 13. Quhill F, Bowling B, Packard RB. Hyaluronidase allergy after ✓ Eye should be in primary gaze position, to peribulbar anaesthesia with orbital inflammation. J Cataract prevent any iatrogenic trauma to optic nerve. Refract Surg 2004;30:916–7. 14. Leibovitch I, Tamblyn D, Casson R, Selva D. Allergic reaction to ✓ Aspirate before injecting LA solution. hyaluronidase: a rare cause of orbital inflammation after ✓ Injection should be done slowly, to decrease the cataract surgery. Clin Exp Ophthalmol 2006;244:944–9. pain perceived by patients during injection. 15. Kumar CM, Dowd TC, Dodds C, Boyce R. Orbital swelling following peribulbar and sub-Tenon’s anaesthesia. Eye ✓ Always feel the tension of the globe with fingers 2004;18:418–20. of the non-blocking hands. 16. Agrawal A, Mclure HA, Dabbs TR. Allergic reaction to hyaluronidaseafter a peribulbar injection. Anaesthesia ✓ Stop injecting the LA solution when there is any 2003;58:493–4. atypical pain, any resistance felt or if there is 17. Lee DS, Kwon NJ. Shivering following retrobulbar block. Can J any abnormal movement of the globe seen Anaesth 1988;35(3):294–6. during injection. 18. Jaichandran VV, Akshay GN, Rashmin G, Prateeba-Devi N. ✓ Always withdraw the needle along the line of Brainstem anesthesia presenting as contralateral third nerve insertion. palsy following peribulbar anesthesia for cataract surgery. Acta Anaesthesiologica Taiwanica 2013;51:135–6.

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19. Gomez RS, Andrade LO, Costa JR. Brainstem anaesthesia after 23. Kallio H, Rosenberg PH. Advances in ophthalmic regional peribulbar anaesthesia. 1997;44(7):732–4. anesthesia. Best Pract Res Clin Anaesth 2005;19(2):215–27. 20. George RB, Hackett J. Bilateral hearing loss following a 24. Robert J. Jedeikin, Syemour Hoffman, Kfar Saba. The retrobulbar block. Can J Anaesth 2005;52(10):1054–7. oculocardiac reflex in Eye-Surgery anesthesia. Anesth Analg 21. Rosen WJ. Brainstem anesthesia presenting as dysarthria. J 1977;56(3):333–4. Cataract Refract Surg 1999;25:1170–1. 25. Salil S, Gadkari . Evaulation of 19 cases of inadvertent globe 22. Cyriac IC, Pineda R. Postoperative complications of periocular perforations due to periocular injections. Indian J Ophthalmol anesthesia. Int Ophthalmol Clin 2000;40(1):85–91. 2007;55:103–7.

How to cite this article Sujatha V. Systemic and Ophthalmic Complications Following Regional Block, Sci J Med & Vis Res Foun 2015;XXXIII:32–36.

36 Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | Clinical practice Control of Intraocular Pressure for Insertion of Intraocular Lens

VV Jaichandran

Consultant Anaesthesiologist, Intraocular pressure (IOP) can be defined as the directly through the scleral interstitium known as Sankara Nethralaya, pressure exerted by the fluid in the eye against the the uveoscleral route or extracanalicular pathway. Chennai, India walls of the eye ball. The average value of IOP is The pharmacological agents which affect IOP 16 ± 5 mmHg. by influencing either aqueous humour production Correspondence to: In ophthalmic surgeries of the intraocular type or drainage are acetazolamide (by inhibiting car- V.V. Jaichandran, such as phacoemuslification cataract surgery, bonic anhydrase), topical drugs with sympathetic Consultant Anaesthesiologist, extracapsular cataract extraction with or without and parasympathetic effects, beta blockers, anaes- Sankara Nethralaya, intraocular lens implantation, small incisional thetic drugs (Thiopental sodium)4, etc. Chennai, India cataract surgery, etc. it is important to prevent Email; [email protected] any rise in IOP before a surgical incision is made. Blood volume in the eye As soon as the sclera is surgically incised, IOP The choroidal circulation accounts for ∼90% of equates atmospheric pressure. total ocular circulation. The choroidal blood If the pressure is high at the time of incision, volume depends on a balance between the rate of the intraocular contents namely the iris, lens, vit- arterial blood inflow to and the rate of venous reous and retina, may be expelled through the blood outflow from the eye. Apart from this, the wound.1 Sudden decompression of hypertensive baseline intraocular blood volume depends on the eye may also increases the likelihood of rupture of tone of the intraocular blood vessels. a sclerotic short posterior ciliary artery in the choroid, thus producing an expulsive haemorrhage Effect of Change of Systemic Arterial Pressure on IOP in the eye.2 The choriocapillaries have the ability to locally It is therefore important to understand the autoregulate and thus the choroidal blood flow various physiological and pharmacological factors remains constant through a range of perfusion that influences the IOP during the perioperative pressures. But this autoregulation is a slow period so that it can be maintained at a low- process, hence a sudden increase in systolic blood normal level before a surgical incision is made. pressure produces a transient acute rise in IOP. The three main physiological factors affecting Moderate decrease in arterial pressures has little IOP during surgery2 are: effect on IOP, but below mean pressure of 90 1. Aqueous humour dynamics, mmHg marked reduction in IOP tends to occur. 2. Blood volume in the eye, 3. Extraocular muscle tone and vitreous Effect of Change in Venous Pressure on IOP volume. Normally, the aqueous venous pressure (15 mmHg) inside the globe is higher than the episcl- eral venous pressure (10 mmHg) outside the globe. fl Aqueous humour uid dynamics This pressure gradient helps in draining the chor- fl The major controlling in uence on IOP is the oidal venous plexuses in the eye. If episcleral dynamic balance between aqueous humour pro- venous pressure increases due to obstruction of duction and its drainage from the eye. the central venous return, then the above pressure gradient falls and blood begins to pool within the Production of aqueous fluid orbit thus resulting in increase in choroidal About 80% of aqueous is formed in the posterior volume in the eye. chamber by the epithelial cells of the ciliary body by an active transport mechanism. The remaining Causes for Increased Central Venous Pressure: 20% is formed in the anterior chamber by simple The following factors can cause an increase in ultrafiltration of plasma through the anterior central venous pressure under local anaesthesia surface of the iris.3 (remember the mnemonics ‘ABC VSR’) • Anxiety, fl Drainage of aqueous uid • Bladder fullness, About 85–95% of aqueous resorption occurs through the trabecular network and Schlemm’s • Cough, canal in the angle between the iris and the • Vomiting, cornea, termed as canalicular outflow. The remaining 5–15% of aqueous resorption occurs • Straining and

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• Restlessness. Sub-tenon’s block It does not cause significant increase in IOP. However, a reduction in IOP was found to occur Intraocular vascular tone and IOP soon after sub-tenon’s injection, possibly due to 10 Intraocular vascular tone is predominantly reduction in muscle tone. affected by PaCO2,PaO2, systemic pH and body temperature.2 A linear correlation exists between Ocular compression PaCO2 and IOP. Thus, respiratory acidosis increases IOP, whereas respiratory alkalosis decreases IOP. A soft (normotensive) eye is preferred during cata- On the other hand, metabolic acidosis causes ract surgery, as in this state the vitreous phase will reduction in IOP while metabolic alkalosis remain concave after lens extraction and minimize increases IOP. Hyperbaric oxygen tensions are intraoperative complications. Hence, to aid in the associated with profound choroidal vasoconstric- diffusion of the drug more uniformly and also to tion and hence this decreases IOP. Hypoxaemia make the globe softer, some form of ocular com- induces choroidal vasodilatation which elevates pression is necessary following a regional block IOP. Systemic hyperthermia has been shown to around the eye. increase in IOP in humans. Hypothermia induces a significant reduction in IOP due to decreased aqueous production and associated Mechanisms by which Ocular Compression help to decrease IOP11 vasoconstriction. • By decreasing the volume of the vitreous, which is ∼50% water in the elderly patients. Extraocular muscle tone and vitreous volume The central nervous system was found to influence • By decreasing the volume of the orbital con- IOP directly through neurogenic control of extrao- tents other than the globe by increasing the cular muscle tone from central diencephalic systemic absorption of orbital exracellular control centres. IOP increases markedly following fluid, including, presumably, injected fluids contraction of the extraocular muscle. General such as anaesthetics. anaesthetic drugs decrease IOP partly by depres- • Increasing the aqueous outflow facility sing these neurogenic centres. mechanism. The vitreous is an unstable gel, consisting mainly of water, whose volume can be radically • Emptying the choroidal vascular bed. altered by changing the osmolarity of the blood reaching it. Thus, acute reduction in IOP can be Methods of Ocular Compression achieved by infusing 20% Mannitol 1.5 g/kg IV. 1. The Super pinky is a hard hollow rubber ball, placed directly over the patient’s eye with the IOP in Regional Eye Blocks help of an elastic strap that is threaded through it, Peribulbar block see Figure 1. There is a large and individual variable rise in IOP 2. Digital ocular compression can be done with following peribulbar block.5,6 the help of the middle three fingers placed over a The degree of IOP elevation depends on the sterile gauze pad on the upper eye lid with the following: middle finger pressing gently on the eye ball. For every 30 s pressure would be released for 5 s to • Volume of local anaesthetic injected allow for the vascular pulsations to occur. The dis- • Tightness of the orbital septae advantage in both the above methods is that the pressure applied is not known, see Figure 2. • Type of local anaesthetic used The lowest IOP elevation occurs with bupiva- caine, a more marked effect is seen with lidocaine and the highest elevation occurs after mepivacaine injection.7 In peribulbar anaesthesia a much larger volume of local anaesthetic is required, as this has to diffuse through the orbital connective tissue septa and the muscle cone to block the motor and sensory nerves in the eye. A larger drug volume in turn raises the IOP to a greater extent compared with a retrobulbar technique where relatively less volume of the drug is required, as this is injected directly inside the muscle cone.8,9 Figure 1. Super pinky.

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may be considered, if conjunctiva is already incised or intraocular lidocaine may be admi- nistered intracamerally. Also, intravenous opioids/sedation may be given. • The patient may strain due to fullness of the bladder especially seen in elderly patients. Always ensure that the patient has emptied his bladder before he/she is shifted into the oper- ation theatre. • Restlessness due to anxiety/phobic attacks can Figure 2. Digital massage to the globe increase the IOP. Reassurance and sedation following injection of local anaesthetic solution. may help these patients. • Posture of the head also influences the pressure inside the eye. An head-up tilt of 15° enhances 3. One of the most popular methods of ocular venous drainage in the eye and a head down compression worldwide remains the Honan tilt produces venous engorgement resulting in balloon,officially known as the Honan IOP raised IOP. So during surgery the patient’s Reducer. This device has several advantages. First, head must be appropriately positioned to avoid it is easy and reliable to use. It allows the user to undue changes in IOP. set a known and steady level of pressure. Normally, the Honan balloon is applied for • Inspite of the above remedial measures, if the 20 min at a pressure of 30 mmHg following an posterior capsule is bulging during surgery, orbital block. then consider 20% Mannitol 1–2 gm/kg IV. Mannitol acts by reducing the volume of vitre- Control of IOP during Eye surgery ous. The mechanism of vitreous shrinkage is Although eye is made soft (normotensive) by commonly considered to result from an giving an adequate globe compression, before a osmotic gradient between the blood and ocular fl surgical incision is made, IOP can still raise tissues, which initially pulls uid from the eye. – during surgery causing technical problems for a Its onset of action is within 20 30 min. surgeon, especially for implanting Intraocular • For immediate reduction of IOP during surgery, lens. lidocaine IV 0.5–1.5 mg/kg given over 15–20 s It is therefore very important to determine the was found to reduce the IOP in about 60–90 s cause for rise in IOP and treat it appropriately. with a peak effect in 8–12 min after which the effect gradually wore off.13 Raise in IOP during surgery: different causes • Thus by these technique IOP can be controlled and its management both preoperatively and intraoperatively and • Squeezing of the eye due to contraction of the helps a surgeon to complete the surgical orbicularis oculi following an inadequate block procedure uneventfully under regional would result in a rise in IOP during surgery. anaesthesia. Supplementation of the block with local anaes- thetic especially a medial peribulbar may be Conclusion considered. Always ensure that eye lid is Even though there are many physiological and anaesthetized before proceeding with the pharmacological factors that influence the IOP surgery. If not, a separate eye lid block has to during surgery, it is the technique and the experi- be given. ence of the anaesthetist practicing ophthalmic • Lid retractors may press on the eye and cause anaesthesia, the skill of the ophthalmologists and bulging of the intraocular contents.12 To the team work that determines the visual outcome reduce this extraocular pressure effect loosen- of the eye surgery. ing the speculum and eyelid sutures would help. References • Inadequate block resulting in pain during 1. Duncalf D. Anaesthesia and intraocular pressure. Bull N Y Acad surgery. Patient may strain resulting in raise in Med 1975;51:374–9. IOP. Assess the site of origin of pain. If the 2. Anthony J. Cunningham, Peter Barry. Intraocular pressure— physiology and implications for anaesthetic management. Can J pain is from peripheral conjunctiva, then Anaes 1986;33:2:195–208. topical proparacine drops may be instilled. If it 3. Harry Murgatroyd, Jane Bembridge. Intraocular pressure. is from limbal conjunctiva and other intraocu- Continuing Education in Anaesthesia. Crit Care Pain 2008 lar structures, sub-tenon’s supplementation (3):100–3.

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4. Dermot F. Murphy. Anesthesia and intraocular pressure—review 9. Sanford DK, Minoso v de Cal OE, Belyea DA. Response of article. Anesth Analg 1985;64:520–30. intraocular pressure to retrobulbar and peribulbar anaesthesia. 5. Morgan JE, Chandna A. Intraocular pressure after peribulbar Ophthalmic Surg Lasers 1998;29(10):815–7. anaesthesia: is the Honan balloon necessary? Br J Ophthalmol 10. Alwitry A, Koshy Z, Browing AC, Kiel W, Holden R. The effect 1995;79(1):46–9. of sub-Tenon’s anaesthesia on intraocular pressure. Eye 6. Richard Bowman, Christopher Liu, Nicholas Sarkies. Intraocular 2001;15:733–5. pressure changes after peribulbar injections with and without 11. Hemkala Trivedi, Hemant Todkar, Vivek Arbhave, compression. Br J Opthalmol 1996;80:394–7. Prashant Bhatia. Ocular anaesthesia for cataract surgery—review 7. Hessemer V. Anesthesia effects on ocular circulation. Synopsis article. www.bhj.org/journal/2003_4503_july/ocular_426.htm. of a study. Fortschr Ophthalmol 1991;88:577–87. 12. Holloway. Control of the eye during general anaesthesia for 8. Lanini PG, Simona FS. Change in intraocular pressure after intraocular surgery. Br J Anaesth 1980;52:671–9. peribulbar and retrobulbar injection: practical sequelae. Klin 13. Uday Goraskha. Intravenous lidocaine hydrochloride as an Monatsbl Augenheilkd 1998;212(5):283–5. intraocular hypotensive agent. www.amainc.com 0ASIS SPRING 2001.

How to cite this article Jaichandran VV. Control of Intraocular Pressure for Insertion of Intraocular Lens, Sci J Med & Vis Res Foun 2015;XXXIII:37–40.

40 Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | Emergencies Peri-operative Management of Medical Emergencies

R Kannan

Consultant Anaesthesiologist, The anaesthetic requirements for ophthalmic • Lightheadedness, dizziness, a floating feeling Sankara Nethralaya, surgery are dictated by the nature of the proposed • Nausea Chennai, India surgery, the surgeon’s preference and the patient’s wishes. The growing trend is towards local anaes- • Vomiting thesia in preference to general anaesthesia in eye Correspondence to: • Sweating R. Kannan, surgery. Complications arising from orbital Consultant Anaesthesiologist, regional anaesthesia may be local, or may mani- • Yawning Sankara Nethralaya, fest systemically and may arise immediately or • The person may be unusually pale Chennai, India may be delayed.1,2 Complications are related to Email: [email protected] the method of administration or local anaesthetic • There may be a drop in blood pressure agent and adjuvant used, and may range from • trivial to the devastating, which may threaten There may be a weak pulse, bradycardia sight or even life. Inspite of taking necessary pre- In an Ophthalmic set up syncope of vasovagal cautions at every step, still certain medical emer- type can occur in the following situations: gencies can occur in an ophthalmic setup. These emergencies may crop out anywhere along the • While administering a regional block way, starting from during administration of the • Pain during surgery block, during surgery or in the postoperative period. • Applying a tight patch over an operated eye In this chapter, we will look into these medical • Removing the patch for postoperative dressing emergencies their causes and management. • Removing or tightening sutures under topical Vasovagal Attack anaesthesia Vasovagal syncope is loss of consciousness caused • Intravitreal or subconjunctival injection of by reduced arterial pressure and blood supply to antibiotics the brain, mediated through neural mechanisms rather than primary cardiac dysfunction. Bradycardia and vasodilation are the characteristic Treatment changes that cause systemic hypotension.3 Mainly symptomatic. Vasovagal attack termed as ‘pre-syncope’ or ‘near- • syncope’ is used to describe a state that resembles Elevation of foot end to improve cerebral the prodrome of syncope but which is not fol- perfusion, 4 lowed by LOC. The trigger may be central, from • Hypotension can be treated with sympatho- psychic stress or pain, or may be initiated periph- mimetic agents, erally by a reduction in venous return to the • heart.5 The Bezold–Jarisch reflex overlaps with Bradycardia with anti-cholinergic agents. vasovagal syncope. It was initially described as a bradycardic response to injection of various alkal- Brainstem anaesthesia oid compounds, and later found to be mediated by Brain-stem anaesthesia is a serious complication 6 chemoreceptors in the heart. The term has now of orbital regional anaesthesia that may occur come to include reactions triggered by cardiac when the injected local anaesthetic agent gains 7 mechanoreceptor activation and it has been used access to the central nervous system. An uninten- to describe perioperative bradycardia with tional injection under the dura mater sheath of 8 hypotension. the optic nerve or directly through the optic foramen may result in subarachnoid spread of the Signs and Symptoms LA. This causes partial or total brainstem anesthe- sia.9–11 Failure to recognize the condition or to • A feeling of heaviness in the legs treat it adequately may be life threatening. • Blurred vision Presenting Features12 • Confusion Onset: The onset of signs and symptoms is incon- • Feeling warm or hot sistent and known to range between seconds and

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40 min after regional block. Commonly, the onset For patients who are stable and anaesthesia is has been reported within 5–10 min after block adequate, surgery can usually be proceeded with. with complete recovery of consciousness within Attention has been focused on ocular position an hour although wide variations exist. when regional anaesthesia of the eye is performed, in an attempt to avoid intrathecal injection and • Confusion, restlessness, slurring of speech, shi- optic-nerve injury. With the globe in superonasal vering, agitation and dizziness. gaze, the optic nerve and the subdural space are • The cardiovascular system is manifested by in close proximity to the introduced needle.13,14 In cyanosis, hypotension and bradycardia but this position, the needle tip can reach the menin- sometimes hypertension and tachycardia have geal sheath surrounding the optic nerve, allowing been reported. local anaesthetic to diffuse towards the subarach- noid space. In keeping the globe in a positing • The respiratory system is manifested by apnoea primary gaze, the optic nerve sheath is less vul- and pulmonary oedema. nerable to needle penetration.15 However, other causes of cardiorespiratory arrest such as anaphylaxis, acute coronary syn- Acute exacerbation of chronic asthma drome, massive pulmonary embolism, stroke and Asthma is a chronic respiratory condition of the seizure should be excluded. lungs. It is caused by inflammation surrounding the airways, decreasing their ability to exchange air. An acute asthma exacerbation occurs when Treatment the symptoms of asthma worsen suddenly present- It is important to initiate appropriate treatment ing with wheeze, cough and difficulty in breath- promptly. ing. Such acute exacerbations can occur in a If symptoms are mild like shivering, restless- known asthmatic patients especially if the face is ness, etc. treatment includes administration of covered with the surgical drapes and surgery is sedation (Midazolam 0.5–1 mg IV), warm air to be prolonged for over longer duration of time. blown with the help of warmer, reassurance and if Patient may complain of tightness of chest, may vitals are within normal limits the surgery can be cough and wheezing may be heard. There may be completed at the earliest time. Constant vigil mon- also desaturation in arterial oxygen and associated itoring of vital signs is very important not only tachycardia and rise in blood pressure due to rest- till the surgery is over but also postoperatively lessness in them. such patients to be monitored in the ICU to look for any other signs of spread of local anaesthetic Prevention into other areas of CVS and respiratory centre of Preoperatively identify such patients and complete the CNS. the surgical procedure at the earliest time interval • If more serious signs and symptoms occur, possible. patient to be resuscitated according to the Advise to continue bronchodilators (oral/inha- principles of Advanced Trauma Life Support lers) and steroids on the day of surgery. by securing the airway, assessing breathing Nebulisation with steroids and bronchodilators and circulation. around 1 h before surgery can be done. • Supporting measures Treatment ´ supplemental oxygen if the patient is Providing Oxygen conscious Intravenous corticosteroids and ´ intravenous fluids bronchodilators. Nebulization/inhalation of high dose steroids. ´ pharmacological circulatory support with the If not responding intubation, mechanical venti- use of vasopressors, vagolytics/vasodilators lation and shift to an Intensive Medical unit for ´ suppression of seizures if present further treatment and observation. • Reassure the patient if still conscious. Seizure • Patients who present with apnoea and become During surgery under loco regional anaesthesia, unconscious, the airway should be secured by convulsions may have several causes such as endotracheal intubation and mechanical venti- ´ Hypoglycemia lation has to be performed rapidly. ´ Medication errors • The vital signs of the patient have to be con- tinually monitored and reassessed. ´ Stroke, severe hypoxia caused by deep sedation • In patients with eye signs and symptoms, ´ Following a cardiac arrest complicating cardiac visual acuity has to be ascertained. ocular reflex

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´ Central nervous system intoxication by spread anaesthesia.16 In this case, the direct exposure of of local anaesthetic agent. brain structures to a low volume of local anaes- thetic agent is similar to intoxication after inad- Several mechanisms may explain the spread of vertent peripheral intra-arterial injection of a local anaesthetic agent used in peribular anaesthe- large volume of local anaesthetic agent, thereby sia to brain structures causing various neuro- clinical presentation is similar. logical signs. Clinical signs have rapid onset and can range The first mechanism is an inadvertent from loss of consciousness to cardiac arrest. intra-arterial injection in the ophthalmic artery or Convulsions may be present or replaced by an its branches. The injection pressure can reverse the electric silence.19 direction of blood flow in the artery and the The second mechanism is inadvertent brainstem anaesthetic solution flows back into the internal anaesthesia. carotid artery and is delivered to the thalamus and Another mechanism that can be evoked is the other midbrain structures.16-18 Indeed the ophthal- absorption of Local Anaesthetic agent by the mic artery is in an abnormal position inferior to arachnoid villi and spread to cerebral structures. the optic nerve in 15% of cases, this exposes inad- This absorption is favoured by manual compres- vertent intra-arterial injection during a peribular sion and the use of hyaluronidase.20

Perioperative causes of convulsions and their management and prevention21 Causes Signs & Symptoms Management Prevention Oculocardiac Bradycardia/cardiac arrest Release of muscle tension Gentle muscle tractions reflex Injection of atropine Injection of atropine Drug errors Tachycardia/bradycardia/ Symptomatic treatment Labelling of syringes convulsions Verification of syringes before (depends on type of drugs injection injected) Hypoglycemia Sweating, drowsiness, confusion, Administration of 25% Perioperative monitoring of blood abnormal behaviour convulsions glucose glucose Hypoxia Desaturation, consciousness Oxygen therapy, liberation Monitoring of oxygen saturation disorders, convulsions. of superior airways, Systematic supplemental oxygen intubation during sedation Monitoring of sedation Stroke Consciousness disorders, Control of airway, control of Management of cardiovascular respiratory distress, haemodynamics drugs haemodynamic instability, parameters Neurological monitoring convulsions Maintaining a stable haemodynamic and normal oxygenation Toxicity of local Somnolence, diplopia, shivering, Airway Management Aspiration before injection anaesthetics Difficulty speaking, arrhythmias Oxygen Reduction of local anaesthetic Convulsions, coma Anticonvulsants doses

Allergic reactions and Anaphylaxis • The ester or amide component, local anaes- A general term for a drug-related clinical event thetics of the ester type are more likely to which either threatens life or disrupts the course produce allergic reactions as they are metabo- of an operation. lised to para-aminobenzoic acid, which is an It is a multisystem response to a drug, or drug allergenic compound.23 combination, to which the patient may or may not • The methylparaben used as a preservative in have been previously exposed. In the ophthalmic the multiple dose vials.24 setup allergies may be encountered with local anaesthetic agent or iodine which is used for • Adjuvants–Hyaluronidase.25 cleaning. Although the incidence of allergic reactions to local anaesthetics has decreased, they are still Presentation documented.27 More than the local anaesthetic Life threatening effects include cardiovascular col- itself, it may be due to the additives used.22 lapse (90%), bronchospasm (30%), angio-oedema Allergic reactions to local anaesthetic agents may (25%) and pulmonary oedema (49%) (Fisher, occur as a result of sensitivity to 1992).

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1 Cutaneous effects Pulmonary Oedema These include flushing and urticaria and Pooling of fluid in the lungs otherwise known as may cause significant fluid depletion. The pulmonary oedema during the perioperative development of a 1-mm layer of subcutaneous period of an ophthalmic surgery has been reported fluid over the whole body is approximately in literature.26 equivalent to a loss of 1.5 l of extracellular This is more commonly encountered in patients volume. with underlying co morbid conditions like Coronary heart disease, Valvular heart disease, 2 Cardiovascular effects etc. Typically, the patient would complain of diffi- Features vary from moderate hypotension culty in breathing under the drapes and then start to cardiovascular collapse. Hypotension is sec- coughing. On auscultation of the lungs basal ondary to release of histamine and other vaso- coarse crepitations can be heard. Pulse oximetry active amines. Changes in heart rate and will show fall in artertial saturation level. rhythm accompany the hypotension. ECG changes most commonly observed was the supraventricular tachycardia (82%) (Fisher, 1986) and AV conduction defects. Management 3 Bronchospasm 1 If the patient is conscious, to be place in an It is serious and can lead to cerebral upright position and oxygen administered. hypoxia if treatment is delayed. 2 Morphine i.v. should be given in 2 mg incre- 4 Glottic oedema ments at 2-min intervals to a total of 10 mg this reduces preload by venodilatation and 5 Gastrointestinal effects—abdominal pain, diar- relieves agitation. rhoea and vomiting. 3 Frusemide i.v. 20–50 mg, especially if there is fluid overload. Acute venodilatation and sub- sequent diuresis results. 4 A vasodilator such as isosorbide dinitrate, Management nitroglycerine or nitroprusside may be used. 1 Resuscitation 5 If the patient is in atrial fibrillation, control of a) Stop administration of the suspected the heart rate with verapamil 5-10 mg i.v. is drug. given slowly or digoxin is required. b) Administer 100% oxygen and maintain 6 In severe myocardial dysfunction, a dilating the airway. inotrope such as dobutamine may be required. – – c) Give adrenaline i.v., 50 100 mcg (0.5 7 If desaturation persists and patient is restless, 1.0 ml of 1:10,000 solution) for cardiovascular tracheal intubation and controlled ventilation collapse. Repeat as required. (Positive End Expiratory pressure) to be done. d) Give crystalloid or colloid i.v 10 ml/kg rapidly to expand the vascular volume. e) Manage the airway. In the presence of Conclusion sever laryngeal oedema and failure of tracheal Although eye surgeries are being treated as minor intubation, tracheostomy or cricothyroidot- risk surgery, patients may present with systemic omy may be required. co-morbidities like cardiac, respiratory, renal dis- orders, etc. These disorders per se, superimposed f) Measure pH and arterial blood gases, by the stress of anaesthesia and surgery and the acidosis may be treated with sodium effects of anaesthetic agents can result in various bicarbonate. medical emergencies like acute left ventricular 2 Second line treatment failure, acute exacerbation of chronic asthma, pul- monary oedema, seizures, etc. Hence, it is very a) Antihistamines important for a surgeon to identify such cases pre- Chlorpheneramine i.v., 10–20 mg given operatively, to remain extra vigil during surgery, slowly over 1 min. if possible to do under topical mode of anaesthe- sia and complete the surgical procedure at the b) Aminophylline earliest time interval possible. Also, it is the duty A dose of 250–500 mg (5 mg/kg) given of anaesthesiologists to provide a complete moni- slowly over 20 min may be required if tored anaesthesia care and to be prepared with all bronchospasm persists. medical emergency drugs and kits both during c) Corticosteroids and after surgery.

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Always be alert while administering a regional 14. UnsOld R, Stanley JA, DeGroot J. The CT-topography of block, keep conversing with the patient, keep your retrobulbar anesthesia. Graefes Arch Klin Exp Ophthalmol – eyes wide open to identify tell tale signs and let 1981;217:125 36. 15. Liu Youl B, Moseley I. Magnetic resonance imaging of the optic your ears concentrate on the sounds of the monitor. nerve in extremes of gaze. Implications for the positioning of the globe for retrobulbar anaesthesia. Br J Ophthalmol References 1992;76:728–33. 1. Rubin A. Complications of local anaesthesia for ophthalmic 16. Gomez R, Andrade L, Rezende Costa JR. Brainstem anaesthesia surgery. Br J Anaesth 1995;75:93–6. after peribulbar anesthesia. Can J Anaesth 1997,44:732–4. 2. Hamilton RC. A discourse on the complicatisons of retrobulbar 17. Aldrete JA, Romo-Salas F, Arora S, Wilson R, Rutherford R. and peribulbar blockade. Can J Ophthalmol 2000;35:363–72. Reverse arterial blood flow as a pathway for central nervous 3. Lewis T. Vasovagal syncope and the carotid sinus mechanism system toxic responses following injection of local anesthetics. with comments on Gowers’s and Nothnagel’s syndrome. Br Med Anesth Analg 1978,57:428–33. J 1932;i:873–6. 18. Meyers EF, Ramirez RC, Boniuk I. Grand mal seizures after 4. Guidelines for the diagnosis and management of syncope retrobulbar block. Arch Ophthalmol 1978,96:847. (version 2009): the Task Force for the Diagnosis and 19. Rosenblatt RM, May DR, Barsoumian K. Cardiopulmonary arrest Management of Syncope of the European Society of after retrobulbar block. Am J Ophthalmol 1980,90:425–7. Cardiology (ESC). Eur Heart J 2009;30:2631–71. 20. Shantha TR. The relationship of retrobulbar local anaesthetic 5. Van Lieshout JJ, Wieling W, Karemaker JM, Eckberg DL. The spread to the neural membranes of the eyeball, optic nerve, and vasovagal response. Clin Sci 1991;81:575–86. arachnoid villi in the optic nerve. Anesthesiology 1990,72(3A): 6. Von Bezold A, Hirt L. Über die physiologischen Wirkungen des A849. essigsauren Veratrins. Untersuchungen aus dem physiologischen 21. Mustapha Bensghir, Najlae Badou, Abdelhafid Houba, Laboratorium Wurzburg 1867;1:75–156. Hicham Balkhi, Charki Haimeur, Hicham Aze Bensghir, et al. 7. Mark AL. The Bezold Jarisch reflex revisited: clinical Convulsions during cataract surgery under peribulbar implications of inhibitory reflexes originating in the heart. JAm anesthesia: a case report. J Med Case Rep 2014,8:218. Coll Cardiol 1983;1:90–102. http://www.jmedicalcasereports.com/content/8/1/218. 8. Hart PS, Yanny W. Needle phobia and malignant vasovagal 22. Jackson D, Chen AH, Bennett CR. Identifying true lidocaine syndrome. Anaesthesia 1998;53:1002–4. allergy. J Am Dent Assoc 1994;125(10):1362–6. 9. Singer SB, Preston R, Hodge WG. Respiratory arrest following 23. Harper NJN, Dixon T, Dugue P, et al. Guidelines: suspected peribulbar anesthesia for cataract surgery: case report and anaphylactic reactions associated with anaesthesia. Anaesthesia review of literature. Can J Ophthalmol 1997;32:450–4. 2009;64:199–211. 10. Loken R, Mervyn Kirker GE, Hamilton RC. Respiratory arrest 24. Anon. Drugdex Consults. Local anaesthetics—allergic reaction. following peribulbar anesthesia for cataract surgery: case report Accessed via Micromedex Healthcare series. http://www. and review of the literature. Can J Ophthalmol 1998;33:225–6. thomsonhc.com/home/dispatch 10/07/2012. 11. Nicoll J, Acharya P, Ahlen K, et al. Central nervous system 25. Borchard K, Puy R, Nixon R. Hyaluronidase allergy: a rare complication after 6000 retrobulbar blocks. Anesth Analg cause of periorbital inflammation. Australas J Dermatol 1987;66:1298–302. 2010;51. 12. You Chuen Chin, Chandra M, Kumar. Brainstem anaesthesia 26. Kumar CM, Lawler PG BJA. Pulmonary edema after peribulbar revisited: mechanism, presentation and management. Trends block. 1999. Anesth Crit Care 2013. 27. Wildsmith JA, Mason A, McKinnon RP, Rae SM. Alleged 13. Drysdale DB. Experimental subdural retrobulbar injection of allergy to local anaesthetic drugs. Br Dent J 1998;184 anesthetic. Ann Ophthalmol 1984;16:716–8. (10):507–10.

How to cite this article Kannan R. Peri-operative Management of Medical Emergencies, Sci J Med & Vis Res Foun 2015;XXXIII:41–45.

Sci J Med & Vis Res Foun February 2015 | volume XXXIII | number 1 | 45 Tips & tricks Management of Difficult Patients under Local Anaesthesia

B Manonmani

Consultant Anaesthesiologist, Introduction Claustrophobic patients Sankara Nethralaya, Our eye hospital is primarily a referral centre and Some patients following the surgical drapes, they Chennai, India we perform ∼12,000 cataract surgeries under local become restless, uncooperative and forcefully anaesthesia in a year. Once surgery has been remove the drapings over their face. These types Correspondence to: advised, patients undergo complete physical of patients can be claustrophobic in nature. It is B. Manomani, examination by our in house , with very important to identify such patients during Consultant Anaesthesiologist, routine lab investigations (Complete hemogram, the preoperative visit or consultation. Once they Sankara Nethralaya, blood sugar, ECG for 40 years and above and are identified, before administration of regional Chennai, India urine examination). The anaesthetists review and block, we generally make them to undergo trail of Email: [email protected] examine the patient on the day of surgery. The drapings and see whether they are able to tolerate above protocol is followed routinely at our the coverings over the face. Sometimes we even Institution for all patients. In spite of the above teach the patient’s attendant about these draping measures, some patients suddenly become unco- and ask them to do the same to the patient at operative in the middle of surgery causing diffi- home so that they can be mentally prepared for culties to both surgeon and anaesthetist. Difficult this during the day of surgery, see Figure 2. Apart patients are those who were uncooperative, not from trail of draping, reassurance and sedation able to please or satisfy them and requiring more with Inj midazolam we manage these types of efforts and skills from both surgeons as well as patients with a special indigenous designed frame anaesthesiologists to manage them successfully. by us, see Figure 3(A–D), which helps in lifting Thus, the main aim of this chapter is to discuss the drapes further away from the face compared our Institutional experiences regarding the various with frames used in normal patients and thereby causes which make a patient uncooperative sud- they can lie down flat comfortably till the surgical denly during cataract surgery and how we procedure is completed. manage these difficult patients on the table.

Difficulty in lying down flat Various causes which makes patients Obesity, kyphoscoliosis, joint ankylosis, etc. are ‘difficult’ during surgery some of the causes which make patients difficult Anxiety to lie down flat in supine position for a long time. Patients posted for cataract surgery usually worry For patients who were obese extra arm support is about their postoperative visual prognosis, espe- attached to the operating table and for those who cially this more common with single eyed patients. are kyphoscoliotic adequate postural support with They need to be explained the surgical procedure pillows underneath is kept, to enable these and the steps involved in administering local patients lie down comfortably at their own anaesthesia in simple, non-technical terms and in posture, see Figure 4. their native language to enable informed consent. With a proper preoperative counselling, holding the patient’s hands with gentle reassurance during Pain during surgery surgery and mild sedation with Inj midazolam Failed regional block resulting in inadequate anal- 0.5-1mg IV mostly these types of patients can be gesia or under topical anaesthesia manipulation of managed. iris can result in pain during surgery. Apart from sympathetic stimulation like rise in heart rate, blood pressure and sweating, patient moves or Iatrogenic breathing difficulty strains to bear the pain. We always encourage the Difficulty in breathing due to surgical plastic patient to communicate with the surgeon orally if drapes sticking to both the nostrils can cause there is any pain during surgery. Analgesic sup- some patients to gasp for breath and in turn plementation is done either by instillation of makes them to move constantly during surgery. topical proparacaine drops, if possible, parabulbar To avoid such an iatrogenic cause of upper airway block given with 2% lignocaine 1–2 cc or inject- obstruction, we have been using an indigenously ing intracameral 2% lidocaine. Also, sedation with designed frames, see Figure 1, which make the Inj midazolam 0.5–1 mg IV is given to allay any sterile plastic drapes to be lifted away from the undue anxiety provoked by pain. But it is always face so that patient can easily breathe through wise to remember that ‘IV Sedation alone will not their nostrils. help to reduce pain caused during surgery’.

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symptoms and so prevent further complications as a result to occur.

Hard of hearing This is particularly seen in elderly patients who have sensory hearing deficit. This can lead to communication problem and they might follow surgeon’s commands. We generally identify it in physical consultation and the same is noted in the file. Also, if hearing aid is used by them we allow it inside the operation theatre to enable them to follow oral instructions.

Figure 1: Indigenous frame for Cataract Perception of visual sensations fi surgery. Au Eong and associates were the rst to document that patients can have frightening visual experi- ence during cataract surgery especially done under topical anaesthesia.2 This fear and anxiety may cause such patients to become suddenly uncooperative in the middle of surgery, provoking panic attacks and thus potentially increase the intraoperative complications. Hence, we generally sedate the patients with Inj.Midazolam 0.015 mg/ kg IV. It has found to reduce both the ability to see and to recall the visual images, after surgery.3

Fullness of bladder Again this is found in geriatric patients in whom commonly hypertrophy of the prostate glands occurs and also in patients with diuretic therapy for antihypertensives. Bladder attains fullness in such patients more so following exposure to cold Figure 2: Patient and the attendant being environment of the operation theatre and it counselled by the anaesthesiologist makes the patient uncomfortable, strains, make preoperatively. unnecessary movements during surgery. Routinely, we ensure such patients empty their bladder before transferring them inside the oper- Inadvertent injection of local anaesthetic agent into ation theatre. central nervous system While performing regional block inadvertent dural Language barrier sheath penetration around the optic nerve by the Our Institution being a tertiary referral centre this needle can result in the spread of local anaesthetic is a simple reason which we often encounter and solution into central nervous system (CNS). The which makes the patient unable to follow com- time of onset of symptoms is variable, but usually mands given by us. If the operation theatre team it develops in the first 15 min after the administra- is not well verse with the language spoken by the tion of local anaesthesia. It can present either patient, then we normally allow a language inter- after surgical drapings and before the start of preter to be with the side of the patient in the surgery or during surgery too. A range of different theatre during surgery. cardiovascular and respiratory signs and symp- toms can occur depending upon the spread of Emotionally upset local anaesthetic solution into the CNS. It can be Patients may be mentally or emotionally disturbed minor like shivering, restlessness, fall in blood due to personal conflicts and are often not forth- pressure, bradycardia, vomiting, etc. to major like coming with their problems unless presented with generalized convulsions, respiratory arrest etc. If it an opportunity to ‘pour their hearts out’. In such a is minor it is treated symptomatically and surgery frame of mind if a patient presents for eye is completed but if it is major surgery is deferred surgery, we have come across few cases in which and it is treated accordingly. Monitoring vital they suddenly become uncooperative (functional) signs at regular interval and maintaining verbal during surgery. Only a detailed and thorough contact with the patient during the block and history both with the patient and attendants can after draping can help to detect early signs and reveal these.

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Figure 3: (A) Indigenously frame view from Head-end, (B) lateral view, (C) under the drapes patient lying comfortably and (D) surgeon operating on a claustrophobic patient.

flat. Treating the patient symptomatically, we advise the surgeon to complete the surgical pro- cedure at the earliest, if not to be abandoned.

Conclusion The various causes which makes the patient to become uncooperative during cataract surgery Figure 4: Adequate pillows and support being are preventable causes. Thus, for a cataract provided to an ankylosis spondylitis patient surgery to be completed uneventfully always do posted for cataract surgery under local a thorough preoperative evaluation, ascertain anaesthesia their native language beforehand, spend more time with them in the preoperative area, explain clearly about the regional anaesthesia and surgi- Other medical causes cal procedure in their native simple language, Hypoglycemic attack can produce excessive advise them especially elderly to empty their sweating, restlessness and discomfort to the bladder before shifting to the operation theatre, patient. If these are the symptoms present, then encourage them to use their hearing aid, if they we check the random blood sugar level. If it is are using it, maintain verbal communication low, we administer 25% Dextrose IV. Acute during block and after draping, sedate them with cardiac failure with pulmonary oedema can cause short acting sedative agents like IV midazolam, dyspnea, restlessness, etc. in the patient. In such a constant reassurance and monitor vital signs at condition, it is difficult for the patient to lie down regular intervals.

How to cite this article Manonmani B. Management of Difficult Patients under Local Anaesthesia , Sci J Med & Vis Res Foun 2015;XXXIII:46–48.

48 Sci J Med & Vis Res Foun January 2015 | volume XXXIII | number 1 | https://www.facebook.com/insightsn For further information / online registration please log on to www.sankaranethralaya.org or email to [email protected]