Home > Encyclopedia of Nursing & Allied Health > Nitrous Oxide

Definition

Nitrous oxide is a colorless, sweet-smelling gas used as an anesthetic, most commonly during dental procedures.

Purpose

Nitrous oxide, also called laughing gas, is the weakest form of sedation to aid in the relaxation of the anxious dental patient. When inhaled, nitrous is absorbed by the body and has a quick-acting calming effect on the patient.

Description

The nitrous gas used in dental offices is actually a blend of two gases: oxygen and nitrous oxide. Mixed together it has a sweet-smelling aroma that gives a sense of well-being and aids in relaxation of the entire body. It causes light, conscious sedation, while the patient still retains the ability to respond to verbal commands.

Nitrous oxide has three kinds of sedative characteristics, including:

• Conscious sedation: Being awake and able to interact vocally with the dental staff, but feeling completely relaxed.
• Inhalation sedation: Becoming sedated through inhalation with the nose or mouth with a sedative agent such as nitrous oxide.
• Psychosedation: Nitrous oxide acts on the psyche or the central nervous system in such a way that pain impulses are not relayed to the cerebral cortex or their interpretation is altered.

According to the American Academy of Pediatric Dentistry, nitrous oxide/oxygen is the safest sedative in dentistry. It is non-addictive, mild, and easily administered to the patient. It is a safe, effective technique for calming patient fears of the dental office and procedures to be performed.

Operation

The concentration of nitrous oxide in the oxygen mixture varies, allowing for a range from light to deep sedation, depending on the apprehension, anxiety, fear, and pain the patient is experiencing. Consideration of the patient risks due to health issues or age may determine the amount of gas used during the dental procedure. Commonly used first in the dental office as a calming agent before an injection of a local anesthetic, nitrous oxide is inhaled through a nosepiece attached to the patient's face. From two separate tanks, two tubes carry the oxygen and the nitrous oxide gases to the nosepiece, where they are combined into one gas. Each tank has separate controls that indicate how much oxygen and nitrous are being used at any given time. The minimum number of people involved in the administration of the gas should be two, the dentist or other licensed professional and an assistant trained to monitor the patient during the procedure to make certain the amount of gas flowing through both tubes is correct. The effectiveness of all procedures using nitrous oxide is greatly enhanced by a quiet environment. Near the end of the dental procedure the flow of nitrous oxide is shut off and the patient is allowed to inhale 100% oxygen. The body quickly dissipates the nitrous oxide, and the patient begins to come out of the conscious sedated state.

Pregnant women should not use or handle nitrous oxide, because studies of pregnant mice and rats exposed to nitrous oxide have linked the use of the gas with birth defects.

Maintenance

Monitoring the control panels from each tank of oxygen and nitrous oxide at the beginning of each day is essential for safe practice. Daily checking of the tubes and nosepiece is vital to make certain they are free of blockages and small tears.

The tanks of oxygen and nitrous oxide should have an oxygen fail-safe system that is calibrated weekly. All emergency equipment should be functional and within reach.

Health care team roles

The dental office staff, including the dentist, dental hygienist, and dental assistant working as team, help create a calm environment. To ensure an adequate supply, the supervising dental assistant should monitor the amount of gas in each tank of oxygen and nitrous oxide, and schedule tank replacements as necessary. At least one back-up tank of each gas should be on hand, in addition to the ones being actively used with patients.

The front office staff maintains a current health history on each patient seen in the office. This health history has all known allergies or medical problems kept up to date for the dentist to refer to when deciding if nitrous oxide is safe for a particular patient.

The dental assistant in charge of the patient during the conscious sedation needs to document the heart rate, blood pressure, respiratory rate, and responsiveness of the patient periodically during the procedure, including the few minutes of recovery period when the patient is inhaling 100% oxygen.

Training

Many state laws require dental offices to have a license for housing a nitrous oxide unit and administering the gas. Dentists and dental hygienists receive training for using the gas in their degree courses. Continuing education courses on how to administer nitrous oxide are offered for the dental assistant. However, the dental assistant can only monitor the patient under the guidance of a licensed general dentist or licensed dental hygienist. A separate test is required to become fully licensed for use without supervision.

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KEY TERMS

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Anesthesia—A complete or partial loss of sensation.

Conscious sedation—Being awake during a procedure, able to respond to questioning, but completely relaxed.

General sedation—Being completely asleep during the procedure.

Inhaled sedation—Reaching a sedated state through inhalation of the nose or mouth with a sedating agent, such as nitrous oxide.

Sedative—An agent having a calming, relaxing effect.

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Cindy F. Ovard, RDA