Inhaled nitrous oxide gas (N2O) or laughing gas, has a long history of use as anesthetics in dental and medical procedures, and can be used as a single agent for brief pediatric procedures. It has a short half-life of 5 minutes and is eliminated essentially non-metabolized through respirations.
Inhaled N2O has analgesic, anxiolytic, and amnestic properties. The mechanism of analgesia is hypothesized to be similar to that of opioids. Anxiolytic and sedative effect is similar to benzodiazepines and may involve GABA receptors.
The N2O is typically given as a mixture of 30% N2O with 70% O2, although 50:50 mixture is also safe. In the ED, it is usually given as monotherapy, as this meets criteria for minimal sedation. Nitrous oxide concentrations > 50% meet criteria for moderate sedation.
Complications are rare (most commonly, nausea/vomiting). Persistent use or abuse can be habit forming and has been associated with anemia and B12 deficiency. Rare side effects include asthma exacerbation, coughing, laryngospasm, cardiac events, and seizures. High nitrous concentrations can cause hypoxia and asphyxiation if sufficient oxygen isn’t supplied (FiO2 < 25%).
Guideline for Monitoring and Management of Pediatric Patients During and After Sedation Diagnostic and Therapeutic Procedures. American Academy of Pediatrics. 2011
Clinical Policy: Critical Issues in the Sedation of Pediatric Patients in the Emergency Department. Annals of Emergency Medicine, 51(4):378-399 (2008)
