Elgueta 2013.

Methods	Design: double‐blind, prospective randomized controlled trial Country: Chile Multisite: no International: no Treatment duration: preoperative period Follow‐up: 24 hours postoperatively Operative procedure(s): elective otorhinolaryngological surgery Randomization unit: participants Analysis unit: individual
Participants	100 participants enrolled ASA I to II children aged 1 to 12 years undergoing elective tonsillectomy or adenotonsillectomy under general anaesthesia Exclusion criteria included: a history of diabetes mellitus; mental retardation; obesity (BMI greater than or equal to the 95th percentile for age and sex); intake of antiemetic or psychoactive medication within 24 hours before surgery; known gastroesophageal reflux disease. Randomized to: group 1 (n = 50, 50%); group 2 (n = 50, 50%); 5 randomized participants were lost to follow‐up after leaving the hospital but were not excluded from the analysis. Main characteristics of participants: age (mean, range): group 1 5.0 years, 1 to 12; group 2 4.5 years, 2 to 9; number of females/males: 48/52.
Interventions	Group 1 (control): intraoperative infusion of 10 mL/kg/hour Ringer's lactate Group 2 (intervention): intraoperative infusion of 30 mL/kg/hour Ringer's lactate Co‐interventions: none stated
Outcomes	Retching and vomiting episodes were documented from the time of tracheal extubation until 24 hours postoperatively by direct observer assessment and telephone questionnaire at 24 hours postoperatively. Administration of antiemetics was also documented and reported. Pain was assessed and reported on arrival to PACU and at 15, 30, 45, 60, 90, and 120 minutes thereafter using either a visual analogue scale (0 to 10) or the Children and Infants Postoperative Pain Scale (CHIPPS), depending on the age and comprehension of the child. Administration of analgesic medication was also documented. Thirst, fever above 100.4 degrees Farenheit, and the highest pain score by either a score of 0 to 10 or the CHIPPS scale was assessed by telephone questionnaire at 24 hours.
Notes	Trial registration: NCT01575600 Funder: departmental funding A priori sample size estimation: stated on page 608 Conducted: July 2010 to March 2012 Declared conflicts of interest: none declared
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random allocation was performed using a computer‐generated number table.
Allocation concealment (selection bias)	Unclear risk	Random allocation was performed using a computer‐generated number table.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants, their parents, and medical staff were blinded to group allocation.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Investigators performing the postoperative assessments were blinded to group allocation.
Incomplete outcome data (attrition bias) All outcomes	Low risk	7 participants were lost to follow‐up, 3 from the control group and 4 from the intervention group.
Selective reporting (reporting bias)	Low risk	All outcomes were reported. An intention‐to‐treat analysis was performed.
Other bias	Low risk	The authors stated they had no conflict of interest to declare and had departmental funding only.