Wang 1999.

Methods	Double‐blind RCT of IPA as a treatment for PONV. "When any episode of vomiting or nausea occurred, patients were randomised, using a random number table to receive a cotton ball soaked with ISO or saline placed under the patient’s nose by the nursing staff. The patient was instructed to sniff twice by a nurse who was blind to group assignment. It should be emphasized that the nursing staffs were instructed not to smell the content of cotton ball and to hold it away from themselves when administering to patient. If the severity of nausea or vomiting improved after a single treatment, a VAS assessment of nausea was obtained every 5 minutes until the patient was discharged or PONV symptoms recurred. Improvement of nausea was defined as a decrease of at least 40% in initial VAS score, and improvement of vomiting was defined as no further episodes of vomiting. If, after treatment, severity of nausea did not improve or retching/vomiting persisted, a second treatment with the same agent was given. Treatment sequences were repeated for a maximum of three times in a 15‐minute period. When severity of either nausea or vomiting failed to improve despite three treatments, intravenous (IV) ondansetron 0.1 mg/kg (maximum 4 mg) was administered. If symptoms persisted, a second dose of ondansetron was administered. For patients who failed to improved after two ondansetron doses (maximum dose: 8mg), other IV antiemetic medications (i.e., 200 mg/kg of metoclopramide; 10 mg/kg droperidol) were given." Setting: acute paediatric day surgery centre, USA
Participants	39 children aged 6‐16 years having surgery under general anaesthesia. ASA physical status I and II. Treatment n = 20. Control n = 19. No significant differences in demographic data across groups. Exclusions: children with a history of chronic illness or developmental delay
Interventions	Inhalations of IPA or saline placebo. Intervention repeated up to 3 times. IV ondansetron was used as 'rescue therapy' if PONV continued.
Outcomes	Severity of nausea and vomiting as measured by 100 mm VAS with a range of 0 = no nausea to 100 = extreme nausea Use of rescue antiemetics as measured by drug and number of doses
Notes	Study author, Dr Shu‐Ming Wang contacted for any further data, however due to the age of the study there was none available. No information reported on funding sources
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"If any episode of vomiting or nausea occurred, patients were randomised, using a random number table to receive a cotton ball soaked with ISO or saline placed under the patient’s nose by the nursing staff." Comment: probably done
Allocation concealment (selection bias)	Unclear risk	Comment: no data on who conducted the allocation and any degree of separation from the conduct of the study
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	"The patient was instructed to sniff twice by a nurse who was blind to group assignment." Comment: personnel probably blinded, participants probably not blinded due to odour of treatment substance
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"The patient was instructed to sniff twice by a nurse who was blind to group assignment. It should be emphasized that the nursing staffs were instructed not to smell the content of cotton ball and to hold it away from themselves when administering to patient." Comment: probably done
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: data reported for all participants. No apparent losses to follow‐up
Selective reporting (reporting bias)	Low risk	Comment: all stated outcomes reported
Other bias	Low risk	Comment: no other sources of bias apparent