Nitrous Oxide: Use and Safety a Peer-Reviewed Publication Written by Ian Shuman, DDS, MAGD, AFAAID

Earn 3 CE credits This course was written for dentists, dental hygienists, and assistants.

Nitrous Oxide: Use and Safety A Peer-Reviewed Publication Written by Ian Shuman, DDS, MAGD, AFAAID

Abstract Educational Objectives Author Profile In dentistry, nitrous oxide is the most commonly used in- The focus of this clinical study is to provide the Ian Shuman, DDS, MAGD, AFAAID, maintains a full-time general, halation anxiolytic and sedation adjunct. It reduces anxiety dental professional with the steps needed to reconstructive, and esthetic dental practice in Pasadena, Maryland. and pain, and memory of the treatment experienced. It is deliver nitrous oxide in a safe and efficacious Since 1995, he has lectured and published on advanced, minimally a valuable component of the armamentarium available to manner. After reading this article, the reader invasive techniques, while teaching procedures to thousands of den- clinicians. When used correctly, it is predictable, effective, should be able to: tists and developing many of the methods. Dr. Shuman has published and safe. 1. Review the history of nitrous oxide numerous articles on topics including adhesive resin dentistry and 2. Understand the properties of nitrous oxide minimally invasive restorative, cosmetic, and implant dentistry. He is 3. Know the safety recommendations a fellow of the Pierre Fauchard Academy. 4. Have the ability to deliver nitrous oxide in a safe manner and know the contraindications Author Disclosure Ian Shuman, DDS, MAGD, AFAAID, has no commercial ties with the sponsors or the providers of the unrestricted educational grant for this course.

Go Green, Go Online to take your course

Publication date: Apr. 2016 Supplement to PennWell Publications Expiration date: Mar. 2019

This educational activity has been made possible through an unrestricted grant from Accutron. This course was written for dentists, dental hygienists and assistants, from novice to skilled. Educational Methods: This course is a self-instructional journal and web activity. Provider Disclosure: PennWell does not have a leadership position or a commercial interest in any products or services discussed or shared in this educational activity nor with the commercial supporter. No manufacturer or third party has had any input into the development of course content. Requirements for Successful Completion: To obtain 3 CE credits for this educational activity you must pay the required fee, review the material, complete the course evaluation and obtain a score of at least 70%. CE Planner Disclosure: Heather Hodges, CE Coordinator does not have a leadership or commercial interest with products PennWell designates this activity for 3 continuing educational credits. or services discussed in this educational activity. Heather can be reached at [email protected] Educational Disclaimer: Completing a single continuing education course does not provide enough information to result Dental Board of California: Provider 4527, course registration number CA# 03-4527-15074 in the participant being an expert in the field related to the course topic. It is a combination of many educational courses “This course meets the Dental Board of California’s requirements for 3 units of continuing education.” and clinical experience that allows the participant to develop skills and expertise. Image Authenticity Statement: The images in this educational activity have not been altered. The PennWell Corporation is designated as an Approved PACE Program Provider by the Scientific Integrity Statement: Information shared in this CE course is developed from clinical research and represents Academy of General Dentistry. The formal continuing dental education programs of this the most current information available from evidence based dentistry. program provider are accepted by the AGD for Fellowship, Mastership and membership Known Benefits and Limitations of the Data: The information presented in this educational activity is derived from the data and information contained in reference section. The research data is extensive and provides direct benefit to the patient maintenance credit. Approval does not imply acceptance by a state or provincial board of and improvements in oral health. dentistry or AGD endorsement. The current term of approval extends from (11/1/2015) to Registration: The cost of this CE course is $59.00 for 3 CE credits. (10/31/2019) Provider ID# 320452. Cancellation/Refund Policy: Any participant who is not 100% satisfied with this course can request a full refund by contacting PennWell in writing. Educational Objectives became its chief proponent and drove inhalation anesthetic The focus of this clinical study is to provide the dental profes- use forward.5 Today, nitrous oxide is used in dental facilities sional with the steps needed to deliver nitrous oxide in a safe worldwide. and efficacious manner. After reading this article, the reader should be able to: Physical Properties 1. Review the history of nitrous oxide Nitrous oxide gas is produced by heating ammonium nitrate 2. Understand the properties of nitrous oxide crystals to 250°C, then scrubbing, compressing, and liquefying 3. Know the safety recommendations the gas before placing it in pressurized tanks.6 Present as both 4. Have the ability to deliver nitrous oxide in a safe manner liquid and gas in the tank, it vaporizes at room temperature as and know the contraindications it is used. The color of the nitrous oxide tank varies by country. In both the United States and Canada, nitrous oxide tanks are Abstract blue, with the pressure measuring approximately 750 pounds In dentistry, nitrous oxide is the most commonly used inhala- per square inch (psi) at 70°C (less at lower temperatures), ir- tion anxiolytic and sedation adjunct. It reduces anxiety and respective of the size of the tank or the quantity of nitrous oxide pain, and memory of the treatment experienced. It is a valu- remaining in it. Once there is no liquid phase remaining in able component of the armamentarium available to clinicians. the tank, the pressure will begin to drop. The shoulder of the When used correctly, it is predictable, effective, and safe. nitrous oxide cylinder is marked with information including, but not restricted to, the brand, manufacturer’s test date and Introduction serial number, inspector’s mark, Department of Transportation Officially known as dinitrogen monoxide by the International (DOT) specifications, and service pressure (figure 1). The oxy- Union of Pure and Applied Chemistry (IUPAC), nitrous gen tank used during nitrous oxide/oxygen sedation is green in oxide (an oxide of nitrogen) is a small inorganic chemical mol- the United States and white in Canada, with other colors used 1 ecule with the formula N2O. It is commonly known as laugh- outside North America. ing gas, nitrous, nitro, NOS, sweet air, protoxide of nitrogen, and hyponitrous oxide. At room temperature, it is a colorless, Physiology non-flammable gas, with a slightly sweet odor and taste.2 It is The mechanism by which anesthetic gases produce general used in surgery and dentistry for its anxiolytic and analgesic anesthesia is unknown. The leading theory suggests that gasses effects. As a general anesthetic, it is very weak and generally bind to proteins within neuronal membranes and modify ion is not used as a single agent but is often used as a carrier gas fluxes and subsequent synaptic transmission.7,8 Unlike other with oxygen in combination with more potent general inhala- anesthetics, nitrous oxide produces a mild analgesic effect at tional gases for surgical anesthesia40. It is known as “laughing sub-anesthetic concentrations. The mechanism for this effect gas” due to its euphoric effects, a property that has led to its most likely involves an interaction with the endogenous opioid recreational use as a dissociative anesthetic. As an industrial system because it is abolished by administration of the opioid gas, it is used as an oxidizer in rockets and in auto racing to antagonist, naloxone. The strongest evidence for these analgesic increase engine output power. It is also a foaming agent for effects is that nitrous oxide stimulates the release of enkephalins, canned whipped cream in the food industry. which bind to opioid receptors that trigger descending norad- renergic pathways.9 This interaction with the endogenous opioid History system may account in part for the abuse potential attributed to The history of nitrous oxide begins with its isolation by the nitrous oxide. The gas also directly modulates a broad range of theologian and scientist Joseph Priestly in 1772.3 In 1798, ligand-gated ion channels.11,12 It may act to imitate nitric oxide Humphry Davy, an English chemist, noted the analgesic (NO) in the central nervous system, and this may be related to effects, and in 1800 he published on the history, chemistry, its analgesic and anxiolytic properties.13 physiology and recreational use of nitrous oxide.4 In his text, Nitrous oxide possesses a minimum alveolar concentration Humphry mentions, “As nitrous oxide appears capable of (MAC) of 104%, making it impossible to induce general anes- destroying physical pain, it may probably be used with ad- thesia below a concentration of 100% and without hyperbaric vantage during surgical operations in which no great effusion conditions. Nitrous oxide sedation appropriately administered of blood takes place.” Unfortunately, surgeons of this era is safe for normal, healthy patients, and its effects on the cardio- failed to take note, and the gas was used primarily for public vascular and respiratory systems are minimal. Although a mild entertainment. Inhalation of nitrous oxide for recreational use myocardial depressant, its minor central sympathetic stimula- began as a phenomenon for the British upper class in 1799, tory effect offsets this. known as “laughing gas parties.” In 1844, Horace Wells, an Nitrous oxide has a low blood/gas partition coefficient American dentist, realized the therapeutic applicability of the (0.47), so only minimal amounts dissolve in blood. The fast gas after self-administration. His associate, William Morton, onset and quick recovery seen with nitrous oxide/oxygen seda-

2 www.ineedce.com Figure 1. Cylinder markings

May be stamped with DOT or ICC (Interstate Commerce Commission) Original hydrostatic test DOT speci cations Elastic expansion of 17.5 cc at 3360 psi DOT-3AA-2015 Service pressure 8H52 E.E.17.5 Serial number 28300 A plus (+) means the Chrome-molybdenum cylinder is approved for Ownership mark PCGC steel used CR.MO. 4 58 + lling to 10% above service pressure Spinning process SPUN 7 63 + Manufacturer’s mark H used M Retest dates 5 68 +

2 x 73 +

3 T 78 + Retest passed Inspector’s speci cations mark If an asterick (*) is present after the test date, the Cylinder front Cylinder rear cylinder may go 10 years before being tested again tion is due to the rapid diffusion and saturation in blood. At a toward the end of a dental appointment has other benefits and concentration of 50% to 70%, rapid uptake occurs from the al- is advocated. This allows discontinuation while providing a veoli to the pulmonary circulation and simultaneously creates a waning placebo influence, and it allows expired nitrous oxide vacuum in the lungs that helps to pull more gas into the alveoli. to enter the scavenging apparatus of the machine, limiting ex-

N2O is a useful adjunct with general anesthetic inhalants. posure of the staff and practitioner to the gas being exhaled, When used in combination, nitrous oxide and the anesthetic which is sound environmental practice. agent are drawn into the lungs, providing a faster onset and quicker recovery, a function of concentration gradients. How- Indications and Benefits ever, after administration is terminated, nitrous oxide is rapidly Nitrous oxide is the most commonly used inhalation anes- diffused back into the lungs along with oxygen and other gases. thetic/sedative used in dentistry and has an excellent safety Due to this, oxygen exchange from the pulmonary circultory record.16,17,18 (See Table 1.) In medicine, the number of office- system is impaired, which can result in diffusion hypoxia. When based anesthesia procedures is increasing more rapidly than are inhalation of high concentrations of nitrous oxide is discontin- hospital-based procedures.19 Nitrous oxide/oxygen conscious ued, high partial pressure in blood rapidly transfers nitrous oxide sedation is frequently used in oral surgery, particularly in the to the alveoli. This dilutes the partial pressure of oxygen in the extraction of third molars, periodontal surgery, implant place- alveoli and may lead to hypoxemia. For this reason, it is conven- ment, and in patients with behavioral or developmental issues. tional practice to provide the patient with 100% oxygen during N2O can be used for anxiolysis or conscious sedation. the (approximately) first five minutes following discontinuation of nitrous oxide. Anxiolysis This concern is more theoretical than clinical, however. Anxiolysis is the prevention or reduction of anxiety. An anxio- Hypoxemia is significant for only a matter of minutes and has lytic is a medication or other intervention that inhibits anxiety. been documented only when high concentrations (>70%) have The main indication for nitrous oxide is to diminish anxiety and been delivered by full mask or by endotracheal tube.14 These fear in patients, and this is often accomplished using low-dose 20 conditions cannot be met with the use of conventional dental N2O and high-dose oxygen. Low-dose N2O can also induce nitrous oxide machines with nasal masks, and any tendency relaxation of psychological tension in dental patients who have for diffusion hypoxia is usually inconsequential.15 Dental N2O dental phobias. Also, high-dose oxygen contributes to manage units will not allow greater then a 70% N2O to 30% O2 ratio as pre-syncope due to pain stimuli. a safety feature and avoid accidental administration of greater In particular, phobic and fearful children who are too young then a 70% N2O gas. Nevertheless, providing 100% oxygen and/or unable to cooperate or overcome their fears are candidates

www.ineedce.com 3 21,22 for N2O use to enable necessary care without further trauma. In surveys of patients not visiting the dentist, fear of Nitrous oxide/oxygen significantly improves cooperation in needles and pain were responsible for up to 28% and 21% of fearful children.23 Restraint for children is an option that is adult patients respectively.27 A number of techniques are avail- controversial and traumatic, whereas the use of N2O/O2 as an able to reduce fear and anxiety and increase cooperation with anxiolytic reduces fear and anxiety and alleviates pain, which treatment. These include behavioral techniques and communi- may encourage rather than discourage future cooperation. cation.28 Hypnosis has been used to reduce fear, the perception of pain, and to alter memory, although not all patients are sug- Table 1: Indications and relative/absolute contraindications for nitrous oxide gestible for hypnosis. Acupuncture and acupressure have also been used.29,30 Indications for nitrous oxide Functional and cognitive deficits can make dental treatment 1. Mildly apprehensive patient difficult for special needs patients. As with fearful patients, be- 2. The frightened child havioral interventions may be helpful. In some circumstances, 3. To reduce awareness of time and fatigue physical support or protective stabilization is used. Nitrous 4. To reduce dental stress oxide/oxygen sedation is an effective method to enable treat- 5. To control gagging ment in patients with reduced mental development as well as 6. When requested by the patient other special needs patients.31,32 Consideration must be given to the ability of the patient to communicate and understand the Relative contraindications to nitrous oxide procedure. 1. Pulmonary disease 2. Respiratory infections Contraindications 3. Pregnancy As with any inhalation drug, there are both relative and abso- 4. Psychiatric patients lute contraindications with N2O. These include patients with 5. Immune-compromised patient respiratory illnesses such as chronic obstructive pulmonary 6. Multiple sclerosis disease (COPD) and asthma, nasal obstruction, and pregnancy, 7. Patient using marijuana or hallucinogenic drugs among others. 8. Blocked middle ear COPD: Patients with chronic obstructive pulmonary dis- 9. Highly apprehensive patient ease have both a reduced ability to move gases into and out of 10. Repeated exposures less than one week apart the lungs because of reversible bronchospasm and irreversible bronchial obstruction. Hypoxemia and hypercarbia can result

Absolute contraindications to N2O from chronic hypoventilation or poor gas exchange across the 1. Nasal obstruction respiratory membranes. Some authorities suggest that nitrous 2. Completely uncommunicative, either due to disability or oxide should be avoided in patients who have significant language barrier chronic obstructive pulmonary disease. Reasons cited include 3. Increased intracranial pressure depression of hypoxemic drive: since high oxygen concentra- 4. As a substitute for local or general anesthesia tions are delivered with nitrous oxide, its use may remove the 5. Patient refusal stimulus for hypoxemic drive. However, if the principles of 6. Active substance abuse or recovered substance abuser moderate sedation are followed, the patient can always be in- 7. Lack of gas recovery affecting dental team structed to breathe more deeply. Asthma: All inhalation agents share a tendency to increase Conscious Sedation respiratory rate but decrease tidal volume. Their net influence Conscious sedation is the use of a combination of drugs to in- on ventilation is reflected as the degree of hypercapnia that oc- duce relaxation and provide some analgesia during a medical curs during administration. Nitrous oxide is distinguished from or dental procedure. Nitrous oxide/oxygen reduces pain and other agents in that it does not reduce net ventilation.8,14 Since anxiety in anxious and fearful patients, including those who N2O is not irritating to the tracheobronchial tree, asthma is not are phobic and unreceptive to other techniques and for whom a contraindication to the use of N2O, provided the patient is the only other alternative may be general anesthesia.24 Con- not having an attack. In fact, there is a benefit to administering scious sedation has been found to be efficacious, reliable, and nitrous oxide since in many asthmatics, the primary precipitant more cost-effective than general anesthesia.25 Pharmacological appears to be emotional stress, especially in children. However, agents and techniques used in dentistry for sedation include no dental procedure should be attempted if the patient is hav- enteral sedation with benzodiazepines or intravenous conscious ing respiratory difficulty due to asthma. sedation using a variety of agents including benzodiazepines, Nasal obstruction: The inability to use a nasal mask is an narcotic analgesics, and hypnotic/amnesic agents. With mul- absolute contraindication to the use of nitrous oxide.18 Gener- tiple drug regimens, extra caution must be exercised.26 ally, such patients fall into one of two categories: (1) those who

4 www.ineedce.com cannot inhale adequately through the nose because of anatomic Hallucinogenic drugs: The use of hallucinogenic drugs 41 and/or disease-induced nasopharyngeal obstructions, and (2) such as marijuana is contraindicated for N2O . Marijuana can those who cannot tolerate and sustain placement of the nasal enhance an already pleasant situation, and conversely increase mask because of psychological and/or cognitive disturbances. the dysphoria of an already stressful situation. Following Examples include patients who are severely phobic, cognitively heavy use of marijuana, the drug may remain in the circula- impaired, and pediatric patients. Additional examples include tion for seven or more days due to its very long half-life. Hal- patients with a deviated septum, nasal polyps, upper respira- lucinogenic drugs act in a similar manner, only with a great tory infection, allergic rhinitis, and severe sinusitis. In this latter deal more intensity, and patients may experience frightening regard, any compromise in patency of the eustachian tube may hallucinations. lead to pressure increases within the middle ear, as previously Intracranial pressure: Nitrous oxide has been shown to mentioned. In fact, it has been suggested that any recent surgery increase intracranial pressure in patients with certain injuries 33 41 of the ear presents a contraindication for nitrous oxide use. and intracranial disorders . Therefore, N2O should not be Any nasal obstruction will severely restrict the patient’s administered to these patients. The role of vascular tone in ability to breathe through the nose. Since nitrous oxide must determining cerebral perfusion pressure is increasingly being be administered via a nasal mask, this becomes a relative con- appreciated.36 It has been suggested that zero flow pressure, traindication depending on the severity of the obstruction. the arterial pressure at which blood flow ceases, represents the Patients who are “mouth breathers,” either due to nasal restric- effective downstream pressure of the cerebral circulation. Ni- tion or simply from habit, do not do well attempting to breathe trous oxide is a cerebral vasodilator and may therefore decrease through the nasal mask and often can not exchange well enough zero flow pressure and increase cerebral perfusion pressure. nasally to be comfortable. However, these effects may be opposed by the increase in intra- Multiple sclerosis: Multiple sclerosis (MS) is a disease cranial blood volume produced by cerebral vasodilation. characterized by nerve demyelination, especially in the central Highly apprehensive patients: Since N2O is a relatively nervous system. Neurologic symptoms of weakness, incoor- weak agent, it should not be used alone in an apprehensive pa- dination, paresthesia, and speech disturbances are common. tient, or as a substitute for anesthesia. Neither occupational exposure to anesthetic agents nor general Blockages: Because nitrous oxide has a solubility coef- anesthesia or usage of nitrous oxide has any impact on MS risk ficient that is 35 times higher than nitrogen, it can quickly and is safe also for people with a genetic susceptibility to the displace nitrogen in any closed cavity, dramatically increasing disease. However, further studies would be valuable in order the pressure within. Therefore, conditions such as blocked to clarify whether other forms of organic solvents contribute to Eustachian tubes, blocked bowel, acute blocked sinusitis and the triggering of MS.34 pneumothorax that allow a rapid pressure increase in a closed

Pregnancy: Nitrous oxide readily enters fetal circulation, body cavity, leading to pain, contraindicates the use of N2O. and because of the possible toxicity of N2O to cells undergo- Depression of bone marrow activity: Exposure to N2O ing mitosis, pregnant patients, especially in the early weeks of causes a depression of bone marrow activity, resulting in a pregnancy, should not receive nitrous oxide electively. How- reduction in the production of erythrocytes and leukocytes43. ever, necessary emergency dental care should not be denied a However, since normal marrow contains a “store” of mature pregnant patient, and if it is determined that N2O is necessary cells sufficient to supply several days’ needs, and the marrow to reduce stress, it may be used following consultation with recovers to return to production within 3 to 4 days, no hema- the obstetrician. Widely used in Europe as a labor analgesic, tologic change is seen following an isolated anesthetic or con- nitrous oxide (N2O) is making a dramatic return in the United scious sedation exposure to nitrous oxide. However, a second States.35 exposure within this period of time will extend inhibition of Psychiatric patients: Psychiatric patients may present synthesis, which may exceed the safety factor of stored cells. sedated due to their normally prescribed medication. It is best Since repeated exposures at close intervals may produce leuko- to consult the patient’s psychiatrist and/or treating physician penia, frequent exposure to nitrous oxide (less than one week before administering N2O. If permitted, these patients should between administrations) should be avoided. be titrated carefully, with close monitoring, as their reactions Immunocompromised: Because N2O seems to reduce may be unpredictable. chemotaxis44 (the motility of leukocytes) toward foreign Inability to communicate: Since much of the patient proteins such as bacteria, as well as to reduce leukocyte ac- monitoring with N2O conscious sedation is done verbally, being tion against tumor cells, patients with compromised immune unable to communicate with the patient becomes a contraindi- systems should avoid nitrous oxide unless urgently required44. cation to the use of N2O. This would include severely mentally This would include patients with AIDS or those taking immu- challenged patients, very young patients, language barriers, or nosuppressive drugs. any condition that prevents easy exchange of thoughts between doctor and patient.

www.ineedce.com 5 Unwilling patients: N2O should never be used on an ous hoses and gas lines. In the portable system, the manifold, unwilling patient. If, after explaining the benefits, the patient the N2O-O2 gas cylinders, and the flowmeter function as one does not want N2O, it should not be used. unit. All components reside in the treatment room. Located on the portable unit, the manifold is a primary component of the

Dental team exposure and unintended inhalation nitrous oxide system. Two or four N2O and O2 gas cylinders

In a review of the advantages and harmful effects of N2O in den- (depending on whether the portable is a 2-cylinder or a 4-cylin- 20 tal management by Ogawa and Misaki, while N2O inhalation der system) may be attached to the manifold, but only one line sedation is effective for dental treatment, leakage of N2O in the for each gas exits the manifold. The exit lines carry the gases operatory affects the health of the dental staff members. In ad- under low pressure (50-55 psi). dition to inadequate ventilation and scavenging systems,37 other equipment issues that may affect team members include equip- Conclusion ment malfunctions, failures, and leaks due to poor connections. Nitrous oxide is a valuable agent that assists patients who are In a study by Staubli et al, vitamin B12 levels were measured in anxious and fearful. It has an excellent safety record when used anesthetic staff applying nitrous oxide.38 It showed reduced vita- for anxiolysis and conscious sedation. There are, however, cer- min B12 plasma levels by measuring homocysteine, methylma- tain parameters that must be followed to ensure that every patient lonic acid, vitamin B12, blood count, and the MTHFR C677T receives the proper and correct mode of treatment in this area. genotype. The study concluded that, provided a safety demand valve is used, the use of nitrous oxide (50%–70%) is safe for the References 1. Arendash AS. Let’s Review: Chemistry, the Physical Setting, 3rd edition. Barron’s vitamin B12 status of medical personnel. Educational Series; 2001:44. 2. Sethi NK, Mullin P, Torgovnick J, Capasso G. Nitrous oxide “whippit” abuse presenting with cobalamin responsive psychosis. J Med Toxicol. 2006;2(2):71-74. Modes of Delivery 3. Partington JR. A History of Chemistry, Volume 3. London, UK: Macmillan; There are two types of nitrous oxide/oxygen delivery systems, 1962. 4. Davy H. Researches Chemical and Philosophical; Chiefly Concerning Nitrous built-in and portable. A built-in system requires a central sys- Oxide, or Dephlogisticated Nitrous Air, and its Respiration. London, UK: J Johnson, 1800. tem with the supply source of N2O-O2 located in a storage area 5. Duncum BM. The Development of Inhalation Anesthesia. London, UK: Royal (cylinder room) separate from the treatment rooms. Flowmeters Society of Medicine Press; 1994. and the accessory equipment required for the delivery of the 6. Clark MS, Brunick AB. Handbook of Nitrous Oxide and Oxygen Sedation, 3rd Edition. Mosby; 2008. gases reside in the treatment rooms. Located in the dental office 7. Evers AS, Crowde CM, Balser JR. General Anesthetics. In: Brunton LL, Lazo cylinder storage room, the manifold is a primary component of JS, Parker KL, editors. Goodman and Gilman’s the Pharmacological Basis of Therapeutics, 11th edition. New York: McGraw-Hill; 2006. the nitrous oxide central system. In general, it serves to join 8. Morgan GE, Mikhail MS, Murray MJ. Clinical Anesthesiology, 4th edition. New multiple compressed-gas cylinders. One or more N O and O York: Lange Medical Books/McGraw Hill; 2006. 2 2 9. Zhang C, Davies MF, Guo TZ, Maze M. The analgesic action of nitrous oxide is cylinders may be attached to the manifold, but only one line for dependent on the release of norepinephrine in the dorsal horn of the spinal cord. each gas exits the manifold. The exit lines carry the gases under Anesthesiology. 1999;91(5):1401-1407. 10. Jastak JT, Donaldson D. Nitrous oxide. Anesth Prog. 1991;38(4-5):142-153. low pressure (50–55 psi) to operatories plumbed for N2O-O2 11. Yamakura T, Harris RA. Effects of gaseous anesthetics nitrous oxide and delivery. Access to N O and O in individual treatment rooms xenon on ligand-gated ion channels. Comparison with isoflurane and ethanol. 2 2 Anesthesiology. 2000;93(4):1095–1101. is achieved via operatory outlets. Cylinder storage room com- 12. Mennerick S, Jevtovic-Todorovic V, Todorovic SM, Shen W, et al. Effect of ponents typically include a manifold with safety pressure relief nitrous oxide on excitatory and inhibitory synaptic transmission in hippocampal cultures. J Neurosci. 1998; 18(23):9716–9726. valves, regulators for each cylinder, an alarm-monitor gauge, 13. Emmanouil DE, Quock RM; Quock. Advances in understanding the actions of a cable, an N O-O supply source (cylinders purchased from nitrous oxide. Anesthesia Prog. 2007;54(1):9-18. 2 2 14. Eger EI. Pharmacokinetics. In: Eger EI, editor. Nitrous Oxide. New York: a gas supply company), tank restraints, various hoses, and gas Elsevier; 1985. lines. Conveniently located somewhere between the cylinder 15. Quarnstrom FC, Milgrom P, Bishop MJ, DeRouen TA. Clinical study of diffusion hypoxia after nitrous oxide analgesia. Anesth Prog. 1991;Jan- storage room and the operatories plumbed for nitrous oxide is Feb;38(1):21-23. a zone valve that can be accessed in case there is reason to shut 16. Berthold C. Enteral sedation: safety, efficacy, and controversy. Compend Contin Educ Dent. 2007;28(5):264-271. down the supply of gas immediately. 17. Dionne RA, Yagiela JA, Moore PA, Gonty A, et al. Comparing efficacy and safety The portable unit is a self-contained delivery system. Mo- of four intravenous sedation regimens in dental outpatients. J Am Dent Assoc. 2001;132(6):740-751. bility is the major advantage of the portable unit. It is usually 18. Becker DE, Rosenberg M. Nitrous oxide and the inhalation anesthetics. Anesth the system of choice in offices where space limitations will not Prog. 2008;55(4):124-131. 19. Blake DR. Office-based anesthesia: dispelling common myths. Aesthet Surg J. accommodate a central storage room or when economic con- 2008;28(5):564-570. straints are an influencing factor. Also, the portable system is 20. Ogawa Y, Misaki T. The advantage and harmful effects of nitrous oxide in dental management. Masui. 2011;60(3):322-329. most likely the answer when frequency of N2O-O2 use is low. 21. Kanagasundaram SA, Lane LJ, Cavalletto BP, Keneally JP, Cooper MG. Efficacy and safety of nitrous oxide in alleviating pain and anxiety during painful Components of the portable unit typically include a manifold procedures. Arch Dis Child. 2001;84(6):492-495. with safety pressure relief valves, regulators for each cylinder, 22. Nathan JE. Effective and safe pediatric oral conscious sedation: philosophy and practical considerations. Alpha Omegan. 2006;99(2):78-82. an alarm monitor gauge, an N2O-O2 supply source (cylinders 23. Collado V, Hennequin M, Faulks D, Mazille MN, et al. Modification of purchased from a gas supply company), tank restraints, vari- behavior with 50% nitrous oxide/oxygen conscious sedation over repeated

6 www.ineedce.com visits for dental treatment: a 3-year prospective study. J Clin Psychopharm. 2015. Accessed February 29, 2016. 2006;26(5):474-481. 38. Staubli G, Baumgartner M, Sass JO, Hersberger M. Laughing gas in a pediatric 24. Rafique S, Banerjee A, Fiske J. Management of the petrified dental patient. emergency department—fun for all participants: vitamin B12 status among Dent Update. 2008;35(3):196-198, 201-202, 204. medical staff working with nitrous oxide. Pediatr Emerg Care. 2015 Nov 13. 25. Prabhu NT, Nunn JH, Evans DJ. A comparison of costs in providing dental 39. Browne DR, Rochford J, O'Connell U, Jones JG. The incidence of care for special needs patients under sedation or general anaesthesia in the postoperative atelectasis in the dependent lung following thoracotomy: the North East of England. Prim Dent Care. 2006;13(4):125-128. value of added nitrogen. Br J Anaesth. 1970 Apr. 42(4):340-6. 26. Dionne RA, Yagiela JA, Coté CJ, Donaldson M, et al. Balancing efficacy and 40. Levering NJ1, Welie JV.: Current status of nitrous oxide as a behavior safety in the use of oral sedation in dental outpatients. J Am Dent Assoc. management practice routine in pediatric dentistry.J Dent Child (Chic). 2011 2006;137(4):502-13. Jan-Apr;78(1):24-30. 27. Crawford S, Niessen L, Wong S, Dowling E. Quantification of patient fears 41. Bryson EO, Frost EA.The perioperative implications of tobacco, marijuana, regarding dental injections and patient perceptions of a local noninjectable and other inhaled toxins. Int Anesthesiol Clin. 2011 Winter;49(1):103-18. anesthetic gel. Compendium. 2005;26(2). 42. Santra S, Das B. Subdural pressure and brain condition during propofol 28. Lyons RA. Understanding basic behavioral support techniques as an alternative vs isoflurane - nitrous oxide anaesthesia in patients undergoing elective to sedation and anesthesia. Spec Care Dentist. 2009;29(1):39-50. supratentorial tumour surgery. Indian J Anaesth. 2009 Feb;53(1):44-51. 29. Wobst AH. Hypnosis and surgery: past, present, and future. Anesth Analg. 43. Weimann J. Toxicity of nitrous oxide. Best Pract Res Clin Anaesthesiol. 2003 2007;104(5):1199-208. Mar;17(1):47-61. 30. Santamaria LB. Non-pharmacologic techniques for treatment of post-operative 44. Parbrook GD. Leucopenic effects of prolonged nitrous oxide treatment. Br J pain. Minerva Anesthesiol. 1990;56:359. Anaesth. 1967 Feb;39(2):119-27. 31. Faulks D, Hennequin M, Albecker-Grappe S, Manière MC, et al. Sedation 45. Kripke BJ, Kupferman A, Luu KC. Suppression of chemotaxis to corneal with 50% nitrous oxide/oxygen for outpatient dental treatment in individuals inflammation by nitrous oxide. Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi with intellectual disability. Dev Med Child Neurol. 2007;49(8):621-625. Xue Za Zhi. 1987 Nov;20(4):302-10. 32. Glassman P. A review of guidelines for sedation, anesthesia, and alternative interventions for people with special needs. Spec Care Dentist. 2009;29(1):9-16. Author Profile 33. Munson ES. Complications of nitrous oxide anesthesia for ear surgery. Anesth Ian Shuman, DDS, MAGD, AFAAID, maintains a full-time general, re- Clin North Am. 1993;11:559-572. constructive, and esthetic dental practice in Pasadena, Maryland. Since 1995, 34. Hedström AK, Hillert J, Olsson T, Alfredsson L. Exposure to anaesthetic he has lectured and published on advanced, minimally invasive techniques, agents does not affect multiple sclerosis risk. Eur J Neurol. 2013;May;20(5):735- while teaching procedures to thousands of dentists and developing many of the 739. methods. Dr. Shuman has published numerous articles on topics including ad- 35. Collins M. A case report on the anxiolytic properties of nitrous oxide during hesive resin dentistry and minimally invasive restorative, cosmetic, and implant labor. J Obstet Gynecol Neonatal Nurs. 2015;44(1):87-92. dentistry. He is a fellow of the Pierre Fauchard Academy. 36. Hancock SM, Eastwood JR, Mahajan RP. Effects of inhaled nitrous oxide 50% on estimated cerebral perfusion pressure and zero flow pressure in healthy volunteers. Anaesthesia. 2005;60(2):129-132. Author Disclosure 37. Kaznosky J. Nitrous Oxide: Hazards and Proper Use Version: Occupational Ian Shuman, DDS, MAGD, AFAAID, has no commercial ties with the spon- Safety Programs. Columbia University in the City of New York website. http:// sors or the providers of the unrestricted educational grant for this course. www.ehs.columbia.edu/NitrousOxideHealthHazards.pdf. Published May 14,

Online Completion Use this page to review the questions and answers. Return to www.ineedce.com and sign in. If you have not previously purchased the program select it from the “Online Courses” listing and complete the online purchase. Once purchased the exam will be added to your Archives page where a Take Exam link will be provided. Click on the “Take Exam” link, complete all the program questions and submit your answers. An immediate grade report will be provided and upon receiving a passing grade your “Verification Form” will be provided immediately for viewing and/or printing. Verification Forms can be viewed and/or printed anytime in the future by returning to the site, sign in and return to your Archives Page. Questions

1. According to the International 4. Unlike other anesthetics, nitrous c. deep anesthesia Union of Pure and Applied Chem- oxide produces a mild analgesic d. none of the above istry (IUPAC), Nitrous oxide is effect at what concentrations? 7. To reduce fear, all of the following officially known as: a. subanesthetic have been used except: a. trinitrogen toluene b. supraanesthetic a. acupuncture b. NOS c. level 4 anesthesia b. pilates c. dinitrogen monoxide d. a and c c. hypnosis d. nitric oxide 5. After administration is terminated, d. acupressure 2. The history of nitrous oxide began the nitrous oxide is rapidly diffused 8. Asthma is not a contraindication with its isolation by the theologian back into the lungs along with oxygen to the use of N2O since N2O is not and scientist Joseph Priestly in the and other gases. Due to this, oxygen irritating to the: year: exchange into the lungs and circula- a. tracheobronchial tree a. 1776 tion is impaired, which can result in: b. alveolar lobes b. 1772 a. hyperalgesia c. secondary bronchus only c. 1798 b. hyperbaricity d. cardiac notch d. 1844 c. diffusion hypoxia 9. In an article by Munson, it has been 3. Nitrous oxide gas is produced by d. hypothermic induction suggested that a contraindication heating ammonium nitrate crystals 6. The use of a combination of drugs to for nitrous oxide would include any to what temperature? induce relaxation and provide some recent surgery of the: a. 100°C analgesia during a medical or dental a. eye b. 150°C procedure is called: b. colon c. 200°C a. anxiolysis c. ear d. 250°C b. conscious sedation d. phalanges www.ineedce.com 7 Questions (Continued)

10. Nitrous oxide is commonly known a. white 25. Which of the following statements as all of the following except which of b. green is true: the following: c. blue a. Blocked Eustachian tubes, bowel, sinusitis a. hypernitrous oxide d. black and pneumothorax that allow a rapid pressure b. NOS 18. What pair of dentists were the earliest increase in a closed body cavity, leading to pain, proponents of inhalation anesthetic? c. sweet air are not contraindications in the use of N2O. d. protoxide of nitrogen a. Priestly and Davy b. The inability to communicate with a patient is b. Wells and Morton not contraindication to the use of N O 11. In the pregnant patient, the use of 2 c. Morton and Downy c. In a pregnant patient, If N O is necessary to nitrous oxide: 2 d. none of the above reduce stress, it may be used following consulta- a. is absolutely contraindicated b. is recommended during early pregnancy 19. To prevent any possibility of hy- tion with the patient’s obstetrician. d. N O is ideal as a stand alone treatment in an c. may be used following consultation with the poxia following cessation of nitrous 2 obstetrician oxide, patients should receive: apprehensive patient, or as a substitute for d. can be used in all cases a. 104% oxygen for ten minutes anesthesia. b. 100% oxygen for three to five minutes 12. Because nitrous oxide appears to 26. Which of the following usually c. a lower dose of nitrous oxide alters cerebral cortex function: increase the effects of marijuana, a d. 80% helium/20% oxygen for ten minutes moderately “stressful” dental experi- a. acetaminophen 20. Patients with compromised im- ence may become: b. bystolic mune systems should avoid nitrous c. beta blockers a. traumatic d. psychotropic drugs b. euphoric oxide unless urgently required, since c. diaphoretic nitrous oxide seems to reduce: 27. In many asthmatics, especially in d. enuretic a. homeostasis children, the primary precipitant to b. macrophage activity an asthma attack appears to be: 13. The prevention or reduction of c. ubertaxis a. nasopharyngeal obstructions anxiety is known as: d. chemotaxis a. conscious sedation b. severe sinusitis b. inhalation sedation 21. Nitrous oxide is tailor made for all c. emotional stress c. a and b but what type of patient: d. cognitive disturbances a. unwilling d. anxiolysis 28. The fast onset and quick recovery b. healthy 14. In the brain, nitrous oxide is a c. middle-aged seen with nitrous oxide/oxygen cerebral: d. cardioverted sedation is due to its rapid diffusion a. vasocontrictor 22. In a study by Staubli et al, staff and saturation in: b. vasodilator a. central nervous system who administered nitrous oxide c. vaso-vagal reactor b. cerebral tissue d. a and c showed a reduction in plasma levels c. blood of which vitamin: d. serum 15. Repeated exposure of nitrous oxide a. B1 at close intervals (less than one week b. B2 29. Which of the following pharma- between administrations) may cause: c. B12 cological agents are used in dentistry a. thrombocytopenia d. D for sedation? b. leukopenia a. benzodiazepines c. hemophilia 23. Nitrous oxide has a solubility coefficient that is 35 times more than: b. narcotic analgesics d. anemia c. hypnotic/amnesic agents a. nitrogen 16. At room temperature, nitrous b. hydrogen d. all of the above oxide is: c. oxygen 30. In 1800, who was the English a. colored d. argon chemist who published the history, b. flammable 24. As an industrial gas, nitrous oxide chemistry, physiology and recre- c. acrid ational use of nitrous oxide? d. sweet tasting is used: a. as an oxidizer in rockets a. Davy Jones 17. In both the United States and b. in auto racing to increase engine output power b. Humphry Davy Canada, nitrous oxide tanks are what c. as a foaming agent for whipped cream c. Davy Crockett color: d. all of the above d. Humphry Bogart

8 www.ineedce.com ANSWER SHEET Nitrous Oxide: Use and Safety

Name: Title: Specialty:

Address: E-mail:

City: State: ZIP: Country:

Telephone: Home ( ) Office ( )

Lic. Renewal Date: AGD Member ID:

Requirements for successful completion of the course and to obtain dental continuing education credits: 1) Read the entire course. 2) Complete all information above. 3) Complete answer sheets in either pen or pencil. 4) Mark only one answer for each question. 5) A score of 70% on this test will earn you 3 CE credits. 6) Complete the Course Evaluation below. 7) Make check payable to PennWell Corp. For Questions Call 800-633-1681 If not taking online, mail completed answer sheet to Educational Objectives PennWell Corp. Attn: Dental Division, 1. Refer to the history of nitrous oxide 1421 S. Sheridan Rd., Tulsa, OK, 74112 2. Understand the properties of nitrous oxide or fax to: 918-831-9804 3. Know the safety recommendations 4. Have the ability to deliver nitrous oxide in a safe manner and know the contraindications For IMMEDIATE results, go to www.ineedce.com to take tests online. Answer sheets can be faxed with credit card payment to Course Evaluation 918-831-9804. 1. Were the individual course objectives met? Payment of $59.00 is enclosed. (Checks and credit cards are accepted.) Objective #1: Yes No Objective #2: Yes No If paying by credit card, please complete the Objective #3: Yes No Objective #4: Yes No following: MC Visa AmEx Discover Please evaluate this course by responding to the following statements, using a scale of Excellent = 5 to Poor = 0. Acct. Number: ______2. To what extent were the course objectives accomplished overall? 5 4 3 2 1 0 Exp. Date: ______Charges on your statement will show up as PennWell 3. Please rate your personal mastery of the course objectives. 5 4 3 2 1 0 4. How would you rate the objectives and educational methods? 5 4 3 2 1 0 1. 16. 5. How do you rate the author’s grasp of the topic? 5 4 3 2 1 0 2. 17. 6. Please rate the instructor’s effectiveness. 5 4 3 2 1 0 3. 18. 7. Was the overall administration of the course effective? 5 4 3 2 1 0 4. 19. 8. Please rate the usefulness and clinical applicability of this course. 5 4 3 2 1 0 5. 20. 9. Please rate the usefulness of the supplemental webliography. 5 4 3 2 1 0 6. 21. 10. Do you feel that the references were adequate? Yes No 7. 22. 11. Would you participate in a similar program on a different topic? Yes No 8. 23. 9. 24. 12. If any of the continuing education questions were unclear or ambiguous, please list them. ______10. 25. 13. Was there any subject matter you found confusing? Please describe. 11. 26. ______12. 27. 14. How long did it take you to complete this course? 13. 28. ______14. 29. 15. What additional continuing dental education topics would you like to see? 15. 30. ______AGD Code 344 PLEASE PHOTOCOPY ANSWER SHEET FOR ADDITIONAL PARTICIPANTS. COURSE EVALUATION and PARTICIPANT FEEDBACK PROVIDER INFORMATION RECORD KEEPING We encourage participant feedback pertaining to all courses. Please be sure to complete the survey included PennWell is an ADA CERP Recognized Provider. ADA CERP is a service of the American Dental association PennWell maintains records of your successful completion of any exam for a minimum of six years. Please with the course. Please e-mail all questions to: [email protected]. to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP contact our offices for a copy of your continuing education credits report. This report, which will list all does not approve or endorse individual courses or instructors, not does it imply acceptance of credit hours credits earned to date, will be generated and mailed to you within five business days of receipt. INSTRUCTIONS by boards of dentistry. All questions should have only one answer. Grading of this examination is done manually. Participants will Completing a single continuing education course does not provide enough information to give the receive confirmation of passing by receipt of a verification form. Verification of Participation forms will be Concerns or complaints about a CE Provider may be directed to the provider or to ADA CERP ar www.ada. participant the feeling that s/he is an expert in the field related to the course topic. It is a combination of mailed within two weeks after taking an examination. org/cotocerp/ many educational courses and clinical experience that allows the participant to develop skills and expertise. COURSE CREDITS/COST The PennWell Corporation is designated as an Approved PACE Program Provider by the Academy of General CANCELLATION/REFUND POLICY All participants scoring at least 70% on the examination will receive a verification form verifying 3 CE Dentistry. The formal continuing dental education programs of this program provider are accepted by the Any participant who is not 100% satisfied with this course can request a full refund by contacting PennWell in writing. credits. The formal continuing education program of this sponsor is accepted by the AGD for Fellowship/ AGD for Fellowship, Mastership and membership maintenance credit. Approval does not imply acceptance Mastership credit. Please contact PennWell for current term of acceptance. Participants are urged to contact by a state or provincial board of dentistry or AGD endorsement. The current term of approval extends from IMAGE AUTHENTICITY their state dental boards for continuing education requirements. PennWell is a California Provider. The (11/1/2015) to (10/31/2019) Provider ID# 320452 The images provided and included in this course have not been altered. California Provider number is 4527. The cost for courses ranges from $20.00 to $110.00. © 2016 by the Academy of Dental Therapeutics and Stomatology, a division of PennWell NOS0416RPT

Customer Service 800-633-1681 ADVANCED NITROUS OXIDE CONSCIOUS SEDATION SYSTEMS

All the right stuff, to help your patient relax!

Digital ltra DigiFlo Automatic Chairside Flushmount Switching ManifoldAlarm Delivery The Digital Ultra™ Flushmount is the The DigiFlo Automatic Switching Remote Flow System and RFS right choice for clinicians who prefer ManifoldAlarm is an automatically Chairmount it is a gas delivery and to work in a digital environment. Its controlled system. It is designed to vacuum control system located sealed ﬂush surface makes it easy to safely and economically deliver nitrous chairside that eliminates scavenging disinfect or barrier-protect. oxide and oxygen gases to dental circuit hoses draping from adjacent operatories. In the event of line pressure cabinetry. Kits are available for a changes, the alarm system provides wide variety of dental chair brands. Year audio and visual alerts. Warranty

Longest flowmeter warranty Switching cylinders is an in the dental industry. automatic process.

IN THE E .S D . A A . M All Accutron products are manufactured

P R Y EM LIT in the USA. IUM QUA Advanced Nitrous Oxide Conscious Sedation