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Home , Dental anesthesia, Dental extraction

Review Article

General in R. Balaji1, M. Dhanraj2*, Arunasree Vadaguru Mallikarjuna2

ABSTRACT

Dentistry, in its surgical and restorative aspect, is in majority based on office practice. Limited work routinely in operation theaters. Majority of the dental procedures can be performed under which is inherently safe. Most dentists are skilled in techniques of local anesthetics and blocks. General anesthesia should not be used as a method of anxiety control but for pain control. All general anesthetics are associated with some risk, and modern dentistry is based on the principle that all potentially painful treatment should be performed under local anesthesia, if at all possible. General anesthesia is strictly limited to those patients and clinical situations in which local anesthesia (with or without ) is not an option such as children or individuals with learning difficulties. This review elucidates the facts and importance of general anesthesia in dentistry. KEY WORDS: Anesthesia, Complication, Extraction, Sedation

INTRODUCTION would otherwise be technically unfeasible. Three broad categories of anesthesia exist: Pain has always been linked to dentistry, representing a • General anesthesia suppresses central nervous persistent challenge to the employment of preventive, system activity and results in unconsciousness and restorative, and surgical dental practice.[1,2] It is total lack of sensation. accepted that various procedures in the dental clinic • Sedation suppresses the central nervous system cause pain such as deep dental fillings, root canal to a lesser degree, inhibiting both anxiety and therapy, tooth extraction and tooth preparation. Even creation of long-term memories without resulting when analgesics are used, painful sensations induced in unconsciousness. by dental procedures often cannot be fully eliminated • Regional and local anesthesia, which block and can contribute to anxiety about further dental transmission of nerve impulses from a specific part therapy, postponed or canceled appointments, and of the body. Depending on the situation, this may impaired quality of life. Anesthesia or anesthesia be used either on its own (in which case the patient (from Greek “without sensation”) is a state of remains conscious) or in combination with general controlled, temporary loss of sensation or awareness anesthesia or sedation. Drugs can be targeted at that is induced for medical purposes. It may include peripheral to anesthetize an isolated part of analgesia (relief from or prevention of pain), paralysis the body only, such as numbing a tooth for dental (muscle relaxation), (loss of memory), work or using a to inhibit sensation or unconsciousness. A patient under the effects of in an entire limb. Alternatively, epidural or spinal [3] anesthetic drugs is referred to as being anesthetized. anesthesia can be performed in the region of the central nervous system itself, suppressing all Anesthesia enables the painless performance of incoming sensation from nerves outside the area medical procedures that would otherwise cause severe of the block. or intolerable pain to an unanesthetized patient or HISTORY OF ANESTHESIA Access this article online There is a long historical association between Website: jprsolutions.info ISSN: 0975-7619 anesthesia and dentistry. Some of the initial anesthetics

1Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India, 2Department of , Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India

*Corresponding author: M. Dhanraj, Department of Prosthodontics, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India. Phone: +91-9841504523. E-mail: [email protected]

Received on: 18-08-2018; Revised on: 23-10-2018; Accepted on: 22-12-2018

Drug Invention Today | Vol 11 • Issue 3 • 2019 715 R. Balaji, et al. given were for dental extractions.[4,5] The first general Children anesthetic administered was for a Majority of outpatient general anesthesia in dentistry and is credited to Horace Wells. Wells, on December is administered to small children who may not 11, 1844, underwent extraction of one of his own tolerate under local anesthesia or some wisdom teeth by a colleague while under the influence may be failures of attempts using local anesthesia. of . In 1846, William Morton, a pupil It is recommended that only specialist pediatric of wells, successfully demonstrated the properties of anesthetists should administer general anesthesia to ether to facilitate dental extraction in Massachusetts. very young children.

In the 1970s and 1980s, there were numerous deaths, Mentally Challenged Patients often in healthy children undergoing simple dental Such patients, due to problems related to physical/ procedures under general anesthesia. The reasons were mental disability, are unlikely to allow safe completion multifactorial, including administration of anesthesia of treatment under local anesthesia. in conditions with substandard , assistance, and resuscitation equipment. Furthermore, patients Dental Phobia [6] were poorly prepared for anesthesia and surgery. Patients in whom long-term dental phobia will be However, currently, there is a worldwide trend that induced or prolonged are administered general an increasing number of children are receiving in the first sitting. The long-term aim in [7-9] treatment under general anesthesia. such patients should be the graduated introduction of treatment under local anesthesia using, if necessary, GENERAL ANESTHESIA conscious sedation and behavior management techniques. General anesthesia for dentistry is not without risk and should not be undertaken as a first-line means Allergy to Local Anesthetics of anxiety control. Considerations should always be It is rare and is due to the amide group of local given to the possibility of techniques anesthetics. The preservative methylparaben can also with or without conscious sedation. Patients requiring cause allergic reactions. However, allergic reaction general anesthesia for dental work are frequently should be differentiated from vasovagal attacks, children or individuals with learning difficulties. The palpitation, and flushing occurring as a result of standards of general anesthesia for dentistry should be absorption of adrenaline present in local anesthetic the same as those in any other setting. solution. General anesthesia in dentistry covers three main Extensive Dentistry and Faciomaxillary Surgery types of surgical procedures: 1. Dental chair anesthesia: It is outpatient anesthesia, Local anesthesia is unsuitable in an awake patient mainly for simple extraction of teeth, especially in when the dentistry is likely to be extensive. children. 2. Day-care anesthesia: It is for minor oral surgery. CONDUCT OF GENERAL 3. In-patient anesthesia: It is for complicated ANESTHESIA extractions, oral surgical procedures, and maxillofacial surgical procedures.[10] Assessment Patients must be assessed in the usual manner, INDICATIONS particularly regarding their medical, social, and surgical suitability for day-case anesthesia. Given Decisions about general anesthesia can only be made the risks of general anesthesia, the possibility of on an individual patient basis, but its use in dentistry performing the procedure under local anesthesia with should be limited to. or without sedation should always be considered. The risks of general anesthesia should be explained to the Acute patient, and consent obtained. In such clinical situations, it would be impossible to achieve adequate local anesthesia and so complete The Clinical Setting treatment without pain, for example, management of Defining the setting in which a general anesthetic is acute dentoalveolar abscess and severe pulpitis. In administered must take into account the “worst case these conditions, drug therapy or drainage procedures scenario” because the uneventful anesthetic is not with other methods of pain relief are in appropriate the problem. Complications of modern anesthesia or unsuccessful. The local anesthetic may not be are rare, but skilled teamwork is required to prevent effective in such conditions due to local change in pH permanent harm to the patient. The further away from and there is a risk of spreading infection also. the support of other clinical services that an anesthetic

716 Drug Invention Today | Vol 11 • Issue 3 • 2019 R. Balaji, et al. is administered, the greater is the risk of death should Aftercare a complication occur. Ideally, all general anesthetics The brief nature of most dental procedures means for dentistry should be administered within the that the majority of patients may be managed on an administrative aegis of the range of services typically “ambulatory” basis. Modern anesthetic drugs permit provided by. The location of any such facility must rapid recovery of consciousness and early discharge, [11] allow easy access for emergency services. but it should be recognized that it may take >24 h for all traces of the agents to be eliminated. Thus, when, Equipment, Monitors, and Drugs in the opinion of the anesthesiologist, patients are All standard equipment, gadgets, monitors, and drugs ready for discharge they must be accompanied by a for anesthesia and resuscitation should be available responsible, legally competent adult who has been and checked before administering anesthesia. given clear instructions regarding the implications This includes (not exclusive) anesthesia machine, of anesthetic “hangover” effects. All patients must vaporizers, oxygen, nitrous oxide, breathing circuits be assessed specifically for fitness for discharge by (adult and pediatric), nasal and facial masks, oral and the anesthesiologist. The administration of general nasal airways, different laryngoscopes with all sizes anesthetics for longer periods of time demands a level of blades, all range of nasal and oral tracheal tubes, of recovery facility that can only be provided in a and independent suction apparatus. Short-acting fast modern-day surgery unit, and standard criteria for the emergence (SAFE) agents have a particular place in day- duration of day-stay procedures apply.[7,15,16] care anesthesia.[6,12] Minimum monitoring standards during anesthesia should be followed. Peripheral Types of Dental Surgery arterial oxygen saturation, electrocardiogram (ECG), Dental surgery comprises exodontia, which is removal non-invasive , and (when of teeth, and conservation, which is filling them, is performed) should always be crowning them, and other restorative measures. done. A precordial stethoscope can be very helpful. • Exodontia: Removal of teeth, it is usually a short The anesthesiologist should be clinically vigilant procedure. and continuously monitor the color of and • Conservation: Conservation operations take longer mucosa, and movements of chest and reservoir bag. and often involve using a drill, which squirts The alarms of monitors should never be switched water, so a pharyngeal pack is necessary to prevent off.[10,13] All resuscitation drugs and equipment aspiration even with a cuffed endotracheal tube.[17] including defibrillator should be immediately available. Moreover, the whole staff should be adequately trained Consent in resuscitation (adult and pediatric). The dental chair Written and informed consent by the patient or parent/ should be capable of head-down tilt and should be guardian if the patient is minor or mentally challenged. movable in the event of power failure. The anesthetist must check all the equipment before use and there Pre-anesthetic Evaluation should be immediate access to spare apparatus in the It is same as for any other major operation. However, it event of failure. Maintenance must be in accordance is pertinent to note that these patients can have swelling with the manufacturer’s instructions. Facilities for the of face, missing or loose teeth, pain, and supply and storage of medical gases must meet the limiting the mouth opening or a maxillomandibular [12] relevant regulations. fixation may be in situ. Thorough airway evaluation should be done and necessary radiographs evaluated, Staffing Standards especially the anteroposterior and lateral views of neck. Each individual must have had appropriate experience of, and training in, dental anesthesia. The nasal patency should be done to facilitate nasal The anesthesiologist must have a dedicated assistant intubation. Such patients may have polytrauma and (operating department assistant or practitioner, nurse complete evaluation is necessary, including complete or dental nurse) with recognized training in this role hemogram. Neurological evaluation is necessary in and no other contemporaneous responsibilities. Since patients with coexisting head injury. The electrolyte the also requires assistance, a minimum of status must be assessed because such patients have a four people are required for any procedure under limited oral intake (usually liquids).[18] general anesthesia. Until consciousness returns, a patient recovering from general anesthesia must be Pre-anesthetic Preparation appropriately protected and monitored continuously in The patient is explained about the anesthetic and adequate recovery facilities. Such monitoring should dental procedure and clear fluids are allowed up to be undertaken by the anesthesiologist or a dedicated 4 h preoperatively. A proper consent should always be individual who is appropriately trained and directly taken. The patient must be accompanied before and responsible to the anesthesiologist.[14] after the surgery and supervised by an adult for 24 h.

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Premedication while the patient is allowed to breathe spontaneously Premedication is rarely required, although the highly through the nasal mask. The nasal mask is held in anxious individual or uncooperative child may benefit position by the anesthetist’s thumbs. A pack is placed from a short-acting benzodiazepine. Eutectic mixture by the dentist at the back of the pharynx to prevent the of local anesthetics or Ametop cream to facilitate patient from breathing through the mouth and to collect intravenous (IV) cannulation in children is useful. any blood or debris from reaching the larynx. A gag or bite block is then positioned on the side opposite the Monitoring extractions to open the mouth. Downward pressure Minimum monitoring standards must be met. This by the dentist during the extraction of mandibular includes capnography in cases where endotracheal teeth has the potential for airway obstruction. This intubation is employed. A full range of resuscitation can be partially prevented if the dentist uses the non- [19] equipment must be available, and all equipment extracting hand to pull up on the patient’s . should be of a standard equal to that used for the A nasopharyngeal airway may be a useful adjunct administration of anesthesia in any other setting. to this technique particularly in the child with large adenoids or tonsils, which may obstruct their airway Induction soon after induction. For extraction of wisdom teeth or Inhalational, IV, and intramuscular inductions all have other more extensive dental procedures, the patient is their place. Inhalational induction is associated with generally intubated. The nasal route is preferred as this an increased incidence of arrhythmias, particularly creates more room for the operating surgeon to work. with halothane. is preferable, due to However, where a relative or absolute contraindication the speed of onset and offset. It also causes fewer to nasal intubation exists or, in the smaller child, arrhythmias and may be a safer option. A full face oral intubation may be used. The tube may then be mask is usually required for an inhalational induction moved around to facilitate access to all four quadrants but may subsequently be exchanged for a nasal mask of the mouth as necessary. A pharyngeal pack is or other airway maintenance devices as described usually inserted. As with simple dental extraction, the below. However, an IV induction using is the laryngeal mask is increasingly being used in this type technique of choice at present in day-case anesthesia. of surgery.[20] In extraction of wisdom teeth, or more extensive dental work, the patient may require endotracheal intubation. Maintenance This may be facilitated by means of a non-depolarizing Maintenance may be either inhalational or IV neuromuscular blocking agent of appropriate duration inhalational maintenance is usually achieved by the of action. The use of the depolarizing neuromuscular administration of a volatile agent in a mixture of either blocking agent succinylcholine is perhaps best avoided nitrous oxide or air in oxygen. As with inhalational in this population of predominantly ambulatory induction, the incidence of arrhythmias is highest patients due to muscle pains. Neuromuscular blocking with the use of halothane and may be as high as 32% agents may be avoided entirely either by intubating (enflurane 10% and 14%).[21] Arrhythmias the patient while breathing spontaneously in a deep are increased in the presence of hypoxia or hypercarbia plane of anesthesia or by administering a high dose of and associated with airway obstruction. The nature alfentanil (up to 30 mg kg1). Maintenance of a deep of arrhythmia also differs between agents with a plane of anesthesia throughout the procedure will then higher incidence of ventricular arrhythmias seen be necessary to facilitate tolerance of the endotracheal with halothane, as compared with the more benign tube, with resultant respiratory depression and supraventricular arrhythmias seen with isoflurane. In hypercarbia. spite of these issues, halothane remained the agent of choice for many years due to the more irritant nature Airway of the other agents available and the associated higher For simple exodontia, the airway has traditionally incidence of coughing, salivation, and laryngospasm. been maintained by means of a nasal mask. More Sevoflurane has been shown to be significantly less recently, the laryngeal mask has become the airway arrhythmogenic than halothane and is also non-irritant of choice as it provides a more definitive airway. and has now superseded halothane as the agent of However, both types of airway may easily be lost choice in the UK. Target-controlled infusions of without the close cooperation and vigilance of the propofol may also be used.[22] dentist and the anesthetist. The laryngeal mask may need to be moved during surgery and is continually at Patient Positioning risk of being dislodged. The two principal nasal masks Historically, patients were anesthetized and operated in use are the Goldman and the McKesson. The airway on in the sitting position. This position was favored as it is maintained by supporting the mandible with the was felt to facilitate surgical access and lessen the risk fingers and preventing the from falling back, of aspiration of blood and debris from the oropharynx.

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These benefits need to be balanced against the risk of as Aldrete post-anesthetic recovery score (uses color, venous pooling or unrecognized vasovagal syncope respiration, circulation, consciousness, and activity as causing a reduction in venous return and hypotension, criteria) can be applied.[25] with the potential for cerebral hypoperfusion and hypoxia. The sitting position is, therefore, now Day-care Anesthesia unusual and patients are anesthetized supine with In day-care facility, patient undergoes formal or without a slight head up tilt. A pharyngeal pack admission to the hospital but is discharged home will still help to prevent debris and secretions from later in the day. The procedures which are usually reaching the posterior oropharynx and being aspirated done are minor oral surgical procedures including in this position. laser treatment and limited extractions. The surgical procedure usually lasts not longer than 1 h and there Recovery are no anticipated post-operative complications. The Pharyngeal packs should be removed and the pharynx patients are usually adults belonging to the American cleared of secretions and debris by suction. Swabs may Society of Anesthesiologists physical status Class I have been placed by the surgeon across the sockets of or II. They are accompanied by a responsible adult the extracted teeth to absorb any ongoing . and home circumstances should be suitable for The patient should be turned into the lateral position, continuing post-operative care. Patients are assessed possibly with a degree of head-down tilt to encourage formally by the anesthesiologist and investigated. the drainage of any blood or secretions away from Usually for patients <40 years, complete blood the larynx. Neuromuscular blocking agents should be examination and urine complete examination are antagonized as appropriate, oxygen 100% administered done. For patients aged 40 years or more, an ECG and any anesthetic agents discontinued. Extubation or is done. Adequate pre-operative fasting is necessary, removal of a laryngeal mask where indicated may be usually 6 h for adults and 4 h for children. If patient is performed either with the patient in a deep plane of anxious, premedication is advised in the form of oral anesthesia or with the patient in a very light plane. The alprazolam or , but it can delay recovery. former technique carries an increased risk of aspiration A proper consent is taken. IV induction with propofol of blood and secretions into the larynx. The patient is done in adults and older children. Neuromuscular must be recovered in appropriate facilities by qualified blockade is achieved with atracurium or vecuronium. staff as with any other general anesthetic. They must The use of depolarizing neuromuscular blocking agent remain in hospital until the usual criteria for discharge succinylcholine is best avoided in such predominantly as a day-case are fulfilled. Pain, nausea, and vomiting ambulatory patients due to muscle pains. Nasotracheal must be controlled, and there should be no continued intubation is commonly done, but orotracheal bleeding. The patient must be accompanied home by intubation can be done if only one side of the mouth is a responsible adult with clear instructions as to what to be operated. Pharynx is properly packed. Anesthesia to do should any post-operative complications arise.[23] is maintained with administration of halothane/ sevoflurane and nitrous oxide in oxygen. Diclofenac Post-operative Analgesia and are administered to reduce pain Extraction of baby teeth is not especially painful. The and swelling. Local anesthetic may be infiltrated into main problem is the psychological trauma of waking the sockets by the surgeon, or a block is performed if up uncomfortable in a strange place. It is important surgery is limited to one or two quadrants. For more that the parents are present, and the administration extensive procedures, short-acting like of 10–15 mg/kg is usually all that is is administered. Long-acting opioid like is [26-28] needed. Analgesia may be given rectally (paracetamol avoided in day-care surgery. or diclofenac suppositories) during the operation, but In-patient Anesthesia for short operations, this is of no major advantage. or paracetamol may be given orally in It is for complicated extractions, oral surgical liquid form in recovery. The extraction of adult teeth procedures, and maxillofacial surgical procedures is undoubtedly painful. Nonsteroidal analgesics are (fixation of maxillary, mandibular, and nasal fractures, effective, and it has been shown that oral diclofenac mandibular set back, maxillary advancement, given on admission is as effective as rectal diclofenac osteotomies, and removal of tumors). given preoperatively.[24] COMPLICATIONS OF DENTAL Fitness for Discharge ANESTHESIA Patients should be clinically observed to be alert, oriented, and able to stand and walk unassisted and Hypoxemia hemodynamically stable. There should be no obvious During dental chair anesthesia, there is high potential surgical complications. Simple scoring systems such for airway obstruction resulting in hypoxemia. This

Drug Invention Today | Vol 11 • Issue 3 • 2019 719 R. Balaji, et al. can result from inhalation of teeth, crowns, portions dehydration, and bacteremia have all been implicated of filling, etc. A sudden decrease in arterial oxygen in temperature rise after anesthesia. Procedures saturation by up to 10% can occur under general provoking bacteremia (extractions) can be managed anesthesia due to upper airway obstruction at the by routine administration of .[35] time of insertion of the Dental Prop and pack and during extractions. This obstruction is accentuated by Non-compliance of Post-operative Instructions coexisting rhinitis and hypertrophied adenoids and Patients undergoing day surgical procedures are given tonsils in young children. Further, in such patients’, instructions not to drink alcohol, drive vehicles, or airway closure occurs at lung volumes well above make important decisions for 24 h. Some patients do functional residual capacity (FRC), producing a large not comply with these instructions. Compliance can be intrapulmonary shunt. During general anesthesia, improved by physician reinforcement of instructions there is further reduction in FRC and intrapulmonary and patient education.[36] shunt is exacerbated and together with propensity for upper airway obstruction, there is greater tendency to REFERENCES hypoxia.[29-31] Increasing fractional inspired oxygen 1. Munshi AK, Hegde AM, Girdhar D. Clinical evaluation of concentration to 0.3 reduces the incidence and severity electronic dental anesthesia for various procedures in pediatric of preoperative desaturation. However, increasing the dentistry. J Clin Pediatr Dent 2000;24:199-204. 2. Fullmer S, Drum M, Reader A, Nusstein J, Beck M. Effect of FiO2 further to 0.5 has not been shown to result in more improvement in oxygen saturation. Application preoperative acetaminophen/hydrocodone on the efficacy of the block in patients with symptomatic of 5 cm H2O continuous positive airway pressure can irreversible pulpitis: A prospective, randomized, double-blind, result in significant reduction in incidence and severity placebo-controlled study. J Endod 2014;40:1-5. of pre-operative arterial desaturation by increasing 3. Stevenson A. Anaesthesia. In: Oxford English Dictionary. FRC and overcoming partial airway obstruction.[32] 3rd ed. Oxford: Oxford University Press; 2005. 4. Bourne JG. in the dental surgery. Br Dent J 1962;113:54-7. Arrhythmias 5. Coleman F. The history of nitrous oxide anaesthesia. Dent Rec There is high incidence of cardiac arrhythmias, 1942;62:143-9. especially with the use of halothane. They are usually 6. Cantlay K, Williamson S, Hawkings J. Anaesthesia for dentistry. Contin Edu Anaesth Crit Care Pain 2005;5:71-5. attributed to light anesthesia, elevated levels of 7. 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It can be easily Canada: Royal College of Dental Surgeons of Ontario; 2005. 16. Webb E, Spoerel WE. General anaesthesia in dentistry. Can reduced at the end of surgery. Anaesth Soc J 1983;30:328-30. 17. Coplans MP, Curson I. Deaths associated with dentistry. Br Operating Room Pollution Dent J 1982;153:357-62. Dental surgeries are areas of high contamination with 18. Parbrook GD. Arterial oxygen saturation during general anaesthesia for dental extraction in children. Anaesthesia anesthetic gases. Efficient ventilation (12–15 room 1988;43:67. changes of air per hour) and scavenging are required. 19. Allen NA, Rowbotham DJ, Nimmo WS. Hypoxaemia during outpatient dental anaesthesia. Anaesthesia 1989;44:509-11. Hyperthermia 20. Suresh D, Purdy G, Wainwright AP, Flynn PJ. Use of continuous positive airway pressure in paediatric dental extraction under Tissue destruction, environmental temperature general anaesthesia. Br J Anaesth 1991;66:200-4. during surgery, administration of certain drugs, 21. Plowman PE, Thomas WJ, Thurlow AC. Cardiac dysrhythmias

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during anaesthesia for oral surgery. The effect of local blockade. 29. Zmyslowski WP, Maloney PL. Nasotracheal intubation in the Anaesthesia 1974;29:571-5. presence of facial fractures. JAMA 1989;262:1327-8. 22. Rosenberg MB, Wunderlich BK, Reynolds RN. Iatrogenic 30. Malhotra N. Retromolar intubation: A technical note. Indian J subcutaneous emphysema during dental anesthesia. Anaesth 2005;49:467-8. 1979;51:80-1. 31. Malhotra N. Retromolar intubation-a simple alternative to 23. Holan G, Kadari A, Engelhard D, Chosack A. Temperature submental intubation. Anaesthesia 2006;61:515-6. elevation in children following dental treatment under general 32. Malhotra N. Submento-tracheal intubation: An alternative to anesthesia with or without prophylactic antibiotics. Pediatr tracheostomy. Egypt J Anaesth 2004;20:443-7. Dent 1993;15:99-103. 33. Malhotra SK, Malhotra N, Sharma RK. Submentotracheal 24. Worthington LM, Flynn PJ, Strunin L. Death in the dental intubation: Another problem and its solution. Anesth Analg chair: An avoidable catastrophe? Br J Anaesth 1998;80:131-2. 2002;95:1127. 25. Webb E. Conditions affecting general anaesthesia in the dental 34. Bala I, Malhotra N. Submentotracheal intubation for skull base office. Can Anaesth Soc J 1964;11:35-40. neurosurgery. J Neurosurg Anesthesiol 2004;16:259-60. 26. Roberts GJ. Inhalation sedation (relative analgesia) with 35. Malhotra N. Use of a tracheal tube exchanger for submento- oxygen/nitrous oxide gas mixtures: 1. Principles. Dent Update tracheal intubation. Anaesthesia 2005;60:828. 1990;17:139-42, 145-6. 36. Correa R, Menezes RB, Wong J, Yogendran S, Jenkins K, 27. Lahoud GY, Averley PA, Hanlon MR. Sevoflurane inhalation Chung F, et al. Compliance with postoperative instructions: conscious sedation for children having dental treatment. A telephone survey of 750 day surgery patients. Anaesthesia Anaesthesia 2001;56:476-80. 2001;56:481-4. 28. Seebacher J, Nozik D, Mathieu A. Inadvertent intracranial introduction of a nasogastric tube, a complication of severe Source of support: Nil; Conflict of interest: None Declared maxillofacial trauma. Anesthesiology 1975;42:100-2.

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