Nitrous Oxide Sedation

CHAPTER 6 Nitrous Oxide Sedation



Marjon B. Jahromi


Nitrous oxide (N2O) sedation was first used as an anesthetic agent in 1844 and can be considered a safe alternative to intravenous (IV) sedation. Nitrous oxide sedation has a long history of safety in the medical and dental community. It is now used by approximately 95% of pediatric dentists and is growing in popularity in general dental and medical offices. Most U.S.-trained dentists will become proficient in N2O sedation as part of their undergraduate dental training. It is not necessary to have extensive experience with IV sedation to be able to perform N2O sedation safely. Gaining experience with N2O sedation can be achieved by observing an experienced practitioner and performing the sedation under supervision. Alternatively, continuing education courses are available. Practitioners who are not familiar with the technique are encouraged to participate.


Nitrous oxide is a relatively insoluble drug and is a rapidly effective sedative with an onset of effects within 2 to 3 minutes of administration and peak effects within 5 minutes. Dosing can be adjusted easily and rapidly to increase or decrease depth of sedation during the procedure. Recovery time is short because elimination through the lungs occurs as rapidly as absorption. N2O is not metabolized in the body to any significant extent and therefore can be used safely on most patients. Patients remain conscious and protective reflexes are intact so there is minimal risk of aspiration or oversedation. In addition, N2O does not cause respiratory depression, making it safer than fentanyl, midazolam, or chloral hydrate. Technically, it is easier to perform than IV sedation because there is no need to gain venous access. Nitrous oxide is administered through a face mask or nasal hood that is simply placed on the patient’s face.



Indications



• Anxious and apprehensive patients undergoing minor office surgical or dental procedures

• Patients needing increased pain reaction threshold

• Patients who are unable to tolerate other sedatives


Contraindications



• Pregnancy (first trimester)

• Airway obstruction and severe asthmatic conditions

• Severe psychiatric disorders (N2O can cause dreaming and hallucinations)

• Pulmonary hypertension

• Pneumothorax

• Severe cardiac disease

• Hyperthyroidism

• Sickle cell anemia

• Chronic bronchitis/emphysema

• Bowel obstruction

Nitrous oxide should not be used to replace local anesthesia but rather as an adjunct to local anesthesia. Nitrous oxide sedation is not a good option to control defiant or erratic behavior.



Advantages



• Rapid onset; monitoring time during recovery is brief.

• Good analgesic and amnestic (limited) properties.

• Unlike IV sedation, when nitrous oxide is used alone, a driver is not needed once the patient has recovered. Patients should be monitored for approximately 30 minutes after the use of N2O to ensure return to baseline functional status before discharge.

• Patients may resume all normal activities after discharge and are not limited in their activities.


Limitations



• Lack of potency

• Expense of equipment

• Training required to become proficient


Equipment



• Inhalation sedation machine (Fig. 6-1)

• Breathing circuit

• Reservoir bag

• Scavenging system

• Nasal hood or facial mask

• Oxygen and N2O supply (N2O is stored in compressed form as a liquid in cylinders)

• Pulse oximeter

• Oral pharyngeal airway available

• Emergency cart with appropriate drugs (consider the Banyan kit; see Chapter 220, Anaphylaxis)

image

Figure 6-1 Accutron 4-Cylinder Portable Manifold.


(Courtesy of Accutron, Inc., Phoenix, Ariz.)



Presedation Assessment and Concerns


Figure 6-2 shows an anesthesia evaluation form that can be used before and after the procedure.


• A complete medical history should be obtained from the patient. Relevant information includes a history of cardiac or respiratory disease, medications, allergies, prior surgeries and complications from anesthesia, history of tobacco use, and history of substance abuse.

• The oropharynx should be thoroughly evaluated for any abnormalities or evidence of obstruction. A history of sleep apnea may indicate airway abnormalities such as narrow airways and tonsillar hypertrophy. Obesity, especially involving the face and neck, may lead to difficulties in spontaneous ventilation under sedation.

• Nitrous oxide will potentiate drugs that depress the respiratory system.

• The procedure and all possible sensations should be described to the patient in advance. Nitrous oxide can produce a feeling of euphoria, dreaminess, and detachment. It can also cause numbness and tingling of the extremities. It may cause nausea, confusion, and sexual hallucinations in higher doses.

image

Figure 6-2 Anesthesia evaluation form used both before and after the procedure to document discharge status.



Preprocedure Patient Preparation



• An experienced assistant trained in Basic Life Support (BLS) should always be present.

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May 14, 2017 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Nitrous Oxide Sedation

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