Name

nitrous oxide:oxygen (Nitronox®)

Class

Gaseous analgesic

Anesthetic

Description/Mechanism

Nitrous oxide: oxygen is a blended mixture of 50% nitrous oxide and 50% oxygen. When inhaled, nitrous oxide/oxygen depresses the CNS, causing anesthesia. In addition, the high concentration of oxygen delivered along with the nitrous oxide increases oxygen tension in the blood, thereby reducing hypoxia.

Onset

2-5 minutes

Duration

2-5 minutes

Indications

Moderate to severe pain

Anxiety

Apprehension

Contraindications

Impaired LOC

Head injury

Chest trauma (pneumothorax)

Inability to comply with instructions

Decompression sickness

Undiagnosed abdominal pain or marked distention

Bowel obstruction

Hypotension

Shock

COPD

Adverse Reactions

Dizziness

Apnea

Expansion of gas-filled pockets

Cyanosis

Nausea and vomiting

Malignant hyperthermia (rare but dangerous)

Drug Interactions

None significant

Supplied

D and E cylinders (blue and green in US) of 50% nitrous oxide and 50% oxygen compressed gas

Dose/Administration

Adult

Invert cylinder several times before use; instruct the patient to inhale deeply through a patient held demand valve and mask or mouthpiece. Nitrous oxide:oxygen is self-administered.

Pediatric

Same as adult.

Special Consideration

Pregnancy Safety: Nitrous oxide has been shown to increase the incidence of spontaneous abortion.

Nitrous oxide is 34 times more soluble than nitrogen and will diffuse into pockets of trapped gas in the patient (intestinal obstruction, pneumothorax, blocked middle ear, etc). As the nitrogen leaves and is replaced by larger amounts of nitrous oxide, increased pressures or volumes may cause serious damage, for example intestinal rupture.

Nitrous oxide is a non-explosive gas.