Summary of findings 4. Isopropyl alcohol compared to saline for treatment of postoperative nausea and vomiting.

Isopropyl alcohol compared to saline for treatment of postoperative nausea and vomiting
Patient or population: adults and children having any type of surgical procedure under general anaesthesia, regional anaesthesia or sedation, as hospital inpatients or outpatients, with existing PONV Setting: hospital post‐anaesthesia care unit or same‐day surgery unit in USA and Iran Intervention: isopropyl alcohol Comparison: saline
Outcomes	Anticipated absolute effects* (95% CI)		Relative effect (95% CI)	№ of participants (studies)	Quality of the evidence (GRADE)	Comments
	Risk with saline	Risk with isopropyl alcohol
Nausea severity Measured by a validated scale or medical or nursing observation	See comment		‐	‐	‐	The studies reporting this comparison did not report this outcome.
Nausea duration (nausea‐free at end of treatment) Measured by participant self‐report or medical or nursing observation	See comment		‐	‐	‐	The studies reporting this comparison did not report this outcome.
Use of rescue antiemetics Assessed by proportion requiring rescue antiemetics Follow‐up: range 5 minutes to participant discharge	Study population		RR 0.39 (0.12 to 1.24)	291 (4 RCTs)	⊕⊝⊝⊝ Very low1, 2, 3
	90 per 100	35 per 100 (11 to 100)
Adverse events (common reactions to aromatherapy include skin rashes, dyspnoea, headache, cardiac arrhythmias, hypotension, hypertension or dizziness)	See comment		‐	‐	‐	The studies reporting this comparison did not report this outcome.
Patient satisfaction with treatment Measured by a validated scale	See comment		‐	‐	‐	The studies reporting this comparison did not report this outcome.
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; PONV: postoperative nausea and vomiting; RCT: randomized controlled trial; RR: risk ratio
GRADE Working Group grades of evidence High quality: we are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low quality: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect Very low quality: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect

¹Poor reporting in Kamalipour 2002 and Langevin 1997 affect confidence in results, downgraded one level.
 ²Wide confidence interval for pooled results, downgraded one level.
 ³Very high heterogeneity between studies, downgraded two levels.