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Year : 2015  |  Volume : 7  |  Issue : 5  |  Page : 248-250  

Nitrousoxide as a conscious sedative in minor oral surgical procedure

Department of Oral and Maxillofacial Surgery, Sree Balaji Dental College and Hospital, Chennai, Tamil Nadu, India

Date of Submission31-Oct-2014
Date of Decision31-Oct-2014
Date of Acceptance09-Nov-2014
Date of Web Publication30-Apr-2015

Correspondence Address:
Dr. Rakesh Mohan
Department of Oral and Maxillofacial Surgery, Sree Balaji Dental College and Hospital, Chennai, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0975-7406.155939

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Nitrous oxide (N 2 O) is the most commonly used inhalation anesthetic in dentistry and is commonly used in emergency centers and ambulatory surgery centers as well. When used alone, it is incapable of producing general anesthesia reliably. However, as a single agent, it has an impressive safety and is excellent for providing minimal and moderate sedation for apprehensive minor oral surgical procedure. In this article, action of N 2 O in overcoming the anxiety and pain of the patient during the minor oral surgery and its advantages and disadvantages, have been reviewed.

Keywords: Anxiety, conscious sedation, minor surgery, nitrous oxide

How to cite this article:
Mohan R, Asir VD, Shanmugapriyan, Ebenezr V, Dakir A, Balakrishnan, Jacob J. Nitrousoxide as a conscious sedative in minor oral surgical procedure. J Pharm Bioall Sci 2015;7, Suppl S1:248-50

How to cite this URL:
Mohan R, Asir VD, Shanmugapriyan, Ebenezr V, Dakir A, Balakrishnan, Jacob J. Nitrousoxide as a conscious sedative in minor oral surgical procedure. J Pharm Bioall Sci [serial online] 2015 [cited 2022 Dec 7];7, Suppl S1:248-50. Available from:

Nitrous oxide (N 2 O) has been available since the mid-1800s but only gained general acceptance as dental inhalation sedation in the second half of the 20 th century. Its use accelerated in the 1970s and 1980s, leveled off for a brief period because of environmental concerns, and then continued to increase into the 21 st century. The purposes of this article are to: Review the indications and contraindications and importance of N 2 O in minor oral surgical procedures.

   What is Nitrous Oxide? Top

Nitrous oxide is a colorless and virtually odorless gas with a faint, sweet smell. It is an effective analgesic/anxiolytic agent causing central nervous system depression and euphoria with little effect on the respiratory system. [1]

   Nitrous Oxide in Oral Surgery Top

Patient anxiety has always been a major issue in dental offices. This course reviews guidelines for use of N 2 O for the dental practitioner and dental staff to manage anxiety and pain.

Dentists have expertise in providing anxiety and pain control for their patients. Although anxiety and pain can be modified by psychological techniques, in many instances pharmacological approaches are required. [2] Analgesia/anxiolysis is defined as diminution or elimination of pain and anxiety in a conscious patient. [3] The patient responds normally to verbal commands. All vital signs are stable, there is no significant risk of losing pro-tective reflexes, and the patient is able to return to preprocedure mobility. In children, analgesia/anxiolysis may expedite the delivery of procedures that are not particularly uncomfortable, but require that the patient not move. [3] It also may allow the patient to tolerate unpleasant procedures by reducing or relieving anxiety, discomfort, or pain. The outcome of pharmacological approaches is variable and depends upon each patient's response to various drugs. The clinical effect of nitrous oxide/oxygen inhalation, however, is more predictable among the majority of the population.


  • The patient should be advised to avoid the heavy meal prior to the use
  • The patient is requested to void if necessary, prior to treatment
  • Patients with contact lenses should be removed as gas leaks around the bridge of the nose may produce drying of the eyes.

   Techniques of Administration Top

Nitrous oxide - oxygen sedation will always begin and end with the patient receiving 100% oxygen. Then, slowly allowed to breathe. A flow rate of 5-6 L/min generally is acceptable to most patients. The flow rate can be adjusted after observation of the reservoir bag. The bag should pulsate gently with each breath and should not be either over or underinflated. Introduction of 100% oxygen for 1-2 min, followed by titration of N 2 O in 10% intervals is recommended. During nitrous oxide/oxygen analgesia/anxiolysis, the concentration of N 2 O should not routinely exceed 50%. Increasing amounts of N 2 O until the desired effect is achieved. It is important that the patient be reminded to breathe through the nose in order for the gas to work. The patient should be questioned as to how they are feeling to ensure an optimal level of nitrous is being administered. Therapeutic levels will vary from patient to patient. If the nitrous level being administered is too low, the patient will not be receiving an effective anxiolytic dose. If the nitrous level is too high, unwanted side-effects may occur.

Studies [4],[5] have shown that children desaturate more rapidly than adolescents, and administering 100% oxygen to the patient for 3-5 min once the nitrous oxide in a closed system has been terminated is important. [4]

The objectives of nitrous oxide/oxygen inhalation include

  • Reduce or eliminate anxiety
  • Reduce untoward movement and reaction to dental treatment
  • Enhance communication and patient cooperation
  • Raise the pain reaction threshold
  • Increase tolerance for longer appointments
  • Aid in treatment of the mentally/physically disabled or medically compromised patient
  • Reduce gagging
  • Potentiate the effect of sedatives.


  • A fearful, anxious, or obstreperous patient
  • Certain patients with special health care needs
  • A patient whose gag reflex interferes with dental care
  • A patient for whom profound local anesthesia cannot be obtained
  • A cooperative child is undergoing a lengthy dental procedure.


  • Chronic obstructive pulmonary diseases
  • Severe emotional disturbances or drug-related dependencies [6]
  • First trimester of pregnancy [7]
  • Treatment with bleomycin sulfate [8]
  • Methylenetetrahydrofolate reductase deficiency. [9]

Whenever possible, appropriate medical specialists should be consulted before administering analgesic/anxiolytic agents to patients with significant underlying medical conditions (e.g. severe obstructive pulmonary disease, congestive heart failure, sickle cell disease, [10] acute otitis media, recent tympanic membrane graft, [11] acute severe head injury [12] ).


  • Easy to administer
  • Onset of action is rapid
  • N 2 O has bland, pleasant, nonirritating order
  • Rapid uptake and elimination of N 2 O ensures that no hangover effect is experienced
  • Recovery is fast
  • Titration is possible
  • There is a wide margin of safety
  • There is cardio-respiratory stability
  • Nausea and vomiting are uncommon
  • Reflex integrity is maintained
  • No preparation of patient is required
  • No need for any escort.


  • Equipment is expensive
  • Patient must be able to breathe through the nose
  • Interference of the nasal hood with injection to anterior maxillary region.

   Conclusion Top

Nitrous oxide/oxygen anesthesia is used in a standard way in dentistry and medicine. And a review of the standards on a regular basis is invaluable to maintain the highest standard of care. Professional use and administration of N 2 O is a tried and true method to managing patients' anxiety for dental procedures. The overall patient experience is enhanced by careful and professional use of this practice-building anesthetic gas. Dental team members must adhere to the best clinical protocols and know the standard of care to ensure absolute safety for the patient and to minimize exposure to themselves. N 2 O is safe and effective for use by qualified dental professionals in a wide variety of situations requiring pain and anxiety management in the minor oral surgical procedures.

   References Top

Paterson SA, Tahmassebi JF. Paediatric dentistry in the new millennium: 3. Use of inhalation sedation in paediatric dentistry. Dent Update 2003;30:350-6, 8.  Back to cited text no. 1
American Dental Association. Position statement: The use of conscious sedation, deep sedation and general anesthesia in dentistry. Available from: [Last accessed on 2008 Nov 24].  Back to cited text no. 2
American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-Anesthesiologists. Practice guidelines for sedation and analgesia by non-anesthesiologists. Anesthesiology 2002;96:1004-17.  Back to cited text no. 3
Patel R, Lenczyk M, Hannallah RS, McGill WA. Age and the onset of desaturation in apnoeic children. Can J Anaesth 1994;41:771-4.  Back to cited text no. 4
Kinouchi K, Tanigami H, Tashiro C, Nishimura M, Fukumitsu K, Takauchi Y. Duration of apnea in anesthetized infants and children required for desaturation of hemoglobin to 95%. The influence of upper respiratory infection. Anesthesiology 1992;77:1105-7.  Back to cited text no. 5
Clark MS, Brunkick AL. Nitrous Oxide and Oxygen Sedation. 3 rd ed. St Louis, Mo: Mosby; 2008. p. 94.  Back to cited text no. 6
Rowland AS, Baird DD, Shore DL, Weinberg CR, Savitz DA, Wilcox AJ. Nitrous oxide and spontaneous abortion in female dental assistants. Am J Epidemiol 1995;141:531-8.  Back to cited text no. 7
Fleming P, Walker PO, Priest JR. Bleomycin therapy: A contraindication to the use of nitrous oxide-oxygen psychosedation in the dental office. Pediatr Dent 1988;10:345-6.  Back to cited text no. 8
Selzer RR, Rosenblatt DS, Laxova R, Hogan K. Adverse effect of nitrous oxide in a child with 5,10-methylenetetrahydrofolate reductase deficiency. N Engl J Med 2003;349:45-50.  Back to cited text no. 9
Ogundipe O, Pearson MW, Slater NG, Adepegba T, Westerdale N. Sickle cell disease and nitrous oxide-induced neuropathy. Clin Lab Haematol 1999;21:409-12.  Back to cited text no. 10
Fish BM, Banerjee AR, Jennings CR, Frain I, Narula AA. Effect of anaesthetic agents on tympanometry and middle-ear effusions. J Laryngol Otol 2000;114:336-8.  Back to cited text no. 11
Moss E, McDowall DG. ICP. increases with 50% nitrous oxide in oxygen in severe head injuries during controlled ventilation. Br J Anaesth 1979;51:757-61.  Back to cited text no. 12

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