The incidence and treatment of prehospital motion sickness.

Objectives: The authors' objectives were: 1) to determine the incidence of motion sickness during ambulance transport on a mountainous route in healthy volunteers, and 2) to determine if droperidol alleviated the signs and symptoms of motion sickness in those volunteers who developed it.

Methods: This was a prospective, randomized, double-blind, placebo-controlled trial. Subjects were healthy volunteers over age 18 and not currently taking an antiemetic. Participants were transported in the back of an ambulance over a mountainous road. Those who developed motion sickness rated their nausea on a 100-mm visual analog scale (VAS) and were randomized to receive placebo (saline) or 2.5 mg droperidol intravenously. Symptoms were recorded on a VAS every 5 minutes until the end of the transport. Incidence of motion sickness was calculated as a percentage with 95% confidence intervals (CIs). Pretreatment characteristics were compared with chi-square tests, and mean VAS scores were compared using t-tests.

Results: Thirty-seven subjects completed the study. Sixteen (43%, 95% CI=27%-59%) developed motion sickness. Fifteen were randomized and completed data collection. Eight received droperidol (mean baseline VAS, 45) and seven received placebo (mean baseline VAS, 40). Droperidol trended toward a greater mean reduction of nausea than placebo at 5 minutes (20 versus 4, p=0.077).

Conclusions: The incidence of motion sickness during ambulance transport in a mountainous setting is substantial. There was a strong trend toward a positive treatment effect with droperidol. Further prospective study in an actual patient setting is warranted.