Nitrous oxide: effective analgesic for vascular and interventional procedures.

During a 2 year period nitrous oxide was used as a sole or supplementary analgesic during 173 vascular or interventional procedures including peripheral angiography and endourologic and endobiliary procedures. The decision to administer nitrous oxide to a given patient was a matter of physician preference. Patients with bowel obstruction, pneumothorax, or chronic obstructive pulmonary disease were excluded from this method of analgesia. The nitrous oxide was administered by a radiology nurse under the supervision of an attending radiologist. Nitrous oxide was used without premedication for 39 procedures and with premedication (usually meperidine 1 mg/kg, promethazine 0.3 mg/kg, or atropine 0.01 mg/kg) in 134 procedures. In 74% of nonpremedicated individuals analgesia was adequate with nitrous oxide alone; 26% required supplemental intravenous medication. In 61% of premedicated individuals pain relief was adequate with nitrous oxide; 39% required supplemental intravenous medication. Complications, including nausea, vomiting, and agitation, occurred in eight patients, but were minor and easily reversed by decreasing the concentration of nitrous oxide. Nasally administered nitrous oxide is a safe, easily used, and effective analgesic.