Amireh 2009.

Methods	Design: double‐blind, prospective randomized controlled trial Country: Jordan Multisite: no International: no Treatment timing: preoperative period Follow‐up: 24 hours postoperatively Operative procedure(s): laparoscopic cholecystectomy Randomization unit: participants Analysis unit: individual
Participants	60 participants enrolled ASA I to II male and female aged 20 to 81 undergoing laparoscopic cholecystectomy Included participants who had fasted for 6 to 8 hours and were the first case of the day on which they were operated Screened participants were excluded if: experienced nausea or vomiting on the morning or surgery; were taking antiemetic drugs; their operation was delayed for any reason; they had a history of cardiovascular, hepatic, renal, gastrointestinal, or neurological disorders. Randomized to: supplemental fluid (n = 30, 50%); conservative fluid (n = 30 50%). Main characteristics of participants: age (mean, range): supplemental fluid group 46 years, 20 to 81; conservative fluid group 48 years, 22 to 79; number of females/males: 46/14.
Interventions	Supplemental fluid group (intervention): preoperative bolus of 10 mL/kg Ringer's lactate Conservative fluid group (control): no preoperative fluid bolus Co‐interventions: none stated
Outcomes	Primary outcomes: nausea was assessed by 100 mm visual analogue scale at 15‐minute intervals throughout recovery up to 24 hours postoperatively. A score of 50 mm or greater was considered significant. Episodes of vomiting during this period were also documented. These outcomes were reported in the following time periods: 0 to 1 hour, 1 to 24 hours, and 0 to 24 hours postoperatively Secondary outcomes included: postoperative analgesic administration.
Notes	Trial registration: not found Funder: none stated A priori sample size estimation: not stated Conducted: August 2003 to May 2004 Declared conflicts of interest: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were prospectively and randomly divided into 2 groups.
Allocation concealment (selection bias)	Low risk	Randomization was performed by the nurse in the preoperative holding area who picked 1 of a prearranged and sealed 60 similar envelopes.=
Blinding of participants and personnel (performance bias) All outcomes	Low risk	The participant, the anaesthesia provider, the postoperative study investigator, and the nurses in recovery area and on the wards were unaware of the participants's group.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The participant, the anaesthesia provider, the postoperative study investigator, and the nurses in recovery area and on the wards were unaware of the participant's group.
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.