Ugur 2007.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 60 Inclusion criteria: 20‐50 years of age; ASA status I or II; undergoing elective surgery under GA Exclusion criteria: history of cardiovascular disease, diabetes mellitus, COPD, renal or hepatic failure; taking drugs that affect the cardiovascular system; SBP < 100 mmHg or > 160 mmHg; DBP < 50 mmHg or > 110 mmHg; HR < 50 bpm or > 120 bpm Type of surgery: elective surgery (type of surgery not specified ‐ we assumed non‐cardiac) Baseline characteristics Intervention group (esmolol) Age, mean (SD): 41.76 (± 12.6) years Gender, M/F: 10/20 Control group (placebo) Age, mean (SD): 36.96 (± 13.3) years Gender, M/F: 9/21 Country: Turkey Setting: hospital; single centre
Interventions	Intervention group (esmolol) Randomized, n = 30; losses = 0; analysed, n = 30 Details: 1.5 mg/kg esmolol given after induction of anaesthesia and before tracheal intubation Control group (placebo) Randomized, n = 30; losses = 0; analysed, n = 30 Details: 5 mL 5% dextrose, given the same as the intervention group
Outcomes	Outcomes measured/reported by study authors: haemodynamic variables; bradycardia (HR < 50 bpm); bronchospasm; arrhythmia (not defined); abnormal ST segments on ECG Outcomes relevant to the review: bradycardia
Notes	Funding/declarations of interest: no funding; study authors declare no conflicts of interest Study dates: not reported Note: study included 2 additional study groups (fentanyl; and lidocaine), which we did not include in the review
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomization chart
Allocation concealment (selection bias)	Unclear risk	Not specified
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blinded randomized trial
Blinding of outcome assessors (detection bias) All outcomes	Low risk	Participants, and anaesthetists who recorded outcome data, were blinded to group allocation
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