Bhattacharjee 2016.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 40 Inclusion criteria: ASA status I or II; 20‐60 years of age; undergoing elective laparoscopic cholecystectomy under GA Exclusion criteria: pre‐existing hypertension; bronchial asthma; diabetes; sinus bradycardia; severe hepatic, renal, endocrine and cardiac dysfunction. Participants in whom surgery could not be completed laparoscopically or had open cholecystectomy were excluded Type of surgery: elective laparoscopic cholecystectomy Baseline characteristics Intervention group (esmolol) Age, mean (SD): 28.4 (± 5.12) years Gender, M/F: 8/12 Control group (placebo) Age, mean (SD): 30.4 (± 5.24) years Gender, M/F: 8/12 Country: India Setting: single centre; hospital
Interventions	Intervention group (esmolol) Randomized, n = 20; losses = 0; analysed, n = 20 (use of ITT analysis not reported) Details: bolus dose of 500 µg/kg esmolol IV, before pneumoperitoneum, during anaesthesia; followed by infusion of 100 µg/kg/min. Intervention given intraoperatively only Control group (placebo) Randomized, n = 20; losses = 0; analysed, n = 20 (use of ITT analysis not reported) Details: saline given same as the intervention group
Outcomes	Outcomes measured/reported by study authors: haemodynamic variables; adverse events (to include bradycardia, hypotension, and hypertension) during postoperative period in the PACU; recovery times Outcomes relevant to the review: bradycardia (HR < 60 bpm); hypotension (MAP < 60 mmHg)
Notes	Funding/declarations of interest: no sources of funding and authors declare no conflicts Study dates: not reported Note: study included a 3rd arm (dexmedetomidine), which we did not include in this review
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Use of a computer‐derived random‐number sequence
Allocation concealment (selection bias)	Low risk	See above
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Study is described as single‐blinded. It is not clear if the anaesthetists are blinded to treatment groups
Blinding of outcome assessors (detection bias) All outcomes	Unclear risk	No details
Incomplete outcome data (attrition bias) All outcomes	Low risk	No apparent losses
Selective reporting (reporting bias)	Unclear risk	Study authors did not report prospective clinical trial registration or publication of a protocol. It was not feasible to effectively assess risk of reporting bias
Other bias	Low risk	Not detected