Nitrous oxide: a nonnarcotic analgesic for emergency use

Thirteen years of clinical experience in Great Britain and five years of experience in the United States have demonstrated the efficacy and safety of 50:50 N2O:O2 for the relief of significant pain without masking symptoms important to diagnosis. This mixture may be safely self-administered by a wide variety of patients who are currently receiving other forms of analgesia. This article discusses the pharmacology and physiologic effects of 50:50 N2O:O2, the indications and contraindications for its use, and a system for delivery of the gas mixture to the patient.