A Randomized Control Equivalence Study of Emergency Medical Services Use of Inhaled Isopropyl Alcohol Versus Ondansetron for Treatment of Prehospital Nausea

Background: Nausea is a common symptom encountered in the emergency medical services (EMS) environment that is often treated with oral or intravenous antiemetic medications, most commonly ondansetron or promethazine. Intravenous medications are beyond the scope of most basic life support (BLS) EMS providers. Isopropyl alcohol (IPA) has long been used to relieve postoperative nausea and was recently shown to be effective in the emergency department. Isopropyl-saturated pads are ubiquitous in ambulances, even at the BLS level.

Purpose: This study compared standard practice intravascular ondansetron (OND) with inhaled IPA for the relief of prehospital nausea.

Methods: This was a prospective open-label randomized controlled equivalence trial comparing 4.0 mg ondansetron given IV with inhaled IPA. Inclusion: Adult EMS patients complaining of nausea rating scale of 5 or greater, with the cognitive ability to consent. Exclusion: minors, prisoners, pregnancy, impaired mental status, or significant upper respiratory infection. After consent, a sealed black box is opened; contents include either three large 70% IPA pads or 4.0 mg of ondansetron and syringe. Ondansetron is administered by standard-practice IV, IPA pads are opened and handed to the patient to self-administer as needed by sniffing through the nares. Nausea rating is monitored before and every 2 minutes after administration up to 10 minutes. Time was stopped at 10 minutes or arrival to the hospital.

Results: Over an 18-month trial, 51 subjects were recruited. Their initial nausea mean rating was 7.5 (95% CI, 6.7–8.2; n=28) and 7.9 (95% CI, 7.3–8.4; n=23) for the IPA and ondansetron groups (p=0.4), respectively. There was no difference in the percent of subjects who reported at least some relief of nausea: 86% in the IPA group versus 91% in the ondansetron group (p=0.08). Final nausea mean rating was IPA 4.3 (95% CI, 3.1–5.5) and ondansetron 3.5 (95% CI, 2.3–4.8; p=0.4). There were also no differences between groups at each of the two-minute intervals.

Conclusion: Inhaled IPA was similarly effective at relieving nausea as the standard-practice intravascular ondansetron in the undifferentiated EMS nausea patient. Additional research needs to be done to validate use of IPA by BLS personnel in the critically ill patient.