Lee 2009.

Methods	Design: blinded, prospective randomized controlled trial Country: South Korea Multisite: no International: no Treatment duration: preoperative/intraoperative period Follow‐up: 24 hours postoperatively Operative procedure(s): laparoscopic cholecystectomy Randomization unit: participants Analysis unit: individual
Participants	90 participants enrolled ASA I to II participants aged 19 to 60 years undergoing laparoscopic cholecystectomy Exclusion criteria included: history of cardiopulmonary disease; endocrine disorders; ringworm; obesity; kidney disease; PONV; motion sickness; fever; conversion from laparoscopic to open procedure. Randomized to: group I (n = 30, 33.3%); group II (n = 30, 33.3%); group III (n = 30, 33.3%). Main characteristics of participants: age (mean, standard deviation): group I 50.5 years, 10.5; group II 51.1 years, 8.1; group III 49.2 years, 8.5; number of females/males: 53/37.
Interventions	Group I (control): preoperative infusion of 5 mL/kg/hour Ringer's lactate Group II (intervention): preoperative infusion of 30 mL/kg/hour Ringer's lactate Group III (intervention): preoperative infusion of 5 mL/kg/hour Ringer's lactate and intraoperative administration of ondansetron 4 mg IV Co‐interventions: none stated
Outcomes	Nausea and vomiting were documented as dichotomous outcomes. These were reported as a composite outcome for the following time points: 0 to 1, 1 to 12, and 12 to 24 hours postoperatively. An risk for the overall 24 hour period was also reported. Antiemetic administration was documented. Pain was measured by visual analogue scale. Nausea, vomiting episodes, and antiemetic administration were also recorded. Pain was assessed using a visual analogue scale at 1, 12, and 24 hours.
Notes	Trial registration: not stated Funder: not stated A priori sample size estimation: not stated Conducted: dates not stated Declared conflicts of interest: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Participants were randomly allocated, but no information on the randomization process was provided.
Allocation concealment (selection bias)	Unclear risk	Participants were randomly allocated, but no information on the randomization process was provided.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Blinding of participants and the perioperative team was not discussed.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The outcome assessor was blinded to group allocation.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No withdrawals were stated.
Selective reporting (reporting bias)	Low risk	All outcomes were reported.
Other bias	Low risk	There were no other sources of bias.