Background Nausea and vomiting is a common ED chief complaint. However, randomised trials comparing antiemetic agents to placebo have not demonstrated superiority. This systematic review investigates the efficacy of inhaled isopropyl alcohol (IPA) compared with usual care or placebo in adults presenting to the ED with nausea and vomiting.
Methods We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, other relevant trial registries, journals, and conference proceedings up to September 2022. Randomised controlled trials using IPA to treat adult ED patients with nausea and vomiting were included. The primary outcome was change in severity of nausea, measured by a validated scale. A secondary outcome was vomiting during the ED stay. We used a random-effects model for the meta-analysis, and assessed certainty of evidence using the Grades of Recommendation, Assessment, Development and Evaluation system.
Results Two trials comparing inhaled IPA to saline placebo and including a total of 195 patients were pooled for meta-analysis of the primary outcome. A third study comparing a group receiving inhaled IPA and oral ondansetron to another group receiving inhaled saline placebo and oral ondansetron did not qualify for the original registered protocol, but was included in a secondary analysis. All studies were judged to be at low or unclear risk of bias. The pooled mean difference for the primary analysis was a reduction in reported nausea of 2.18 on a 0–10 scale (95% confidence interval (CI) 1.60 to 2.76), favouring IPA over placebo, where the minimum clinically significant difference was defined as 1.5. The evidence level was graded as moderate, due to imprecision from low patient numbers. Only the study included in the secondary analysis assessed the secondary outcome of vomiting, and did not find a difference between intervention and control.
Conclusion This review suggests that IPA likely has a modest effect in reducing nausea in adult ED patients, compared with placebo. Larger multicentre trials are needed, as the evidence is limited by few trials and patients.
PROSPERO registration number CRD42022299815
- emergency department
- Systematic Review
Data availability statement
All data relevant to the study are included in the article or uploaded as supplemental information.
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Handling editor David Metcalfe
Contributors SL and JT developed the study protocol, reviewed the search strategy, extracted and analysed data, and contributed to drafting and reviewing the manuscript. SL takes responsibility for the overall content and is guarantor of the study.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.
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