Louizos 2007.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 162 Inclusion criteria: cigarette smokers; ASA I‐III; undergoing elective microlaryngeal surgery under GA; having smoked an average of 20‐30 cigarettes daily for > 10 years Exclusion criteria: average in‐hospital HR < 55 bpm or SBP < 100 mmHg; COPD; sick sinus syndrome, conduction abnormalities on the ECG; cardiac failure; receive monoamine oxidase inhibitors or reserpine Type of surgery: elective microlaryngeal surgery Baseline characteristics Intervention group (esmolol 1 mg/kg) Age, mean (SD): 44 (± 8) years Gender, M/F: 28/26 Intervention group (esmolol 2 mg/kg) Age, mean (SD): 43 (± 11) years Gender, M/F: 26/29 Control group (placebo) Age, mean (SD): 41 (± 8) years Gender, M/F: 26/27 Country: Greece Setting: single centre; hospital
Interventions	Intervention group (esmolol 1 mg/kg) Randomized, n = 54; losses = 0; analysed, n = 54 (use of ITT analysis not reported) Details: 1 mg/kg esmolol in 30 mL normal saline given during induction of anaesthesia Intervention group (esmolol 2 mg/kg) Randomized, n = 55; losses = 0; analysed, n = 55 Details: 2 mg/kg esmolol in 30 mL normal saline given during induction of anaesthesia Control group (placebo) Randomized, n = 53; losses = 0; analysed, n = 53 Details: 30 mL normal saline given during inductin of anaesthesia
Outcomes	Outcomes measured/reported by study authors: haemodynamic variables; tachycardia (type of tachycardia not defined); bronchospasm, bradycardia, hypotension, hypertension, volume of rescue esmolol Outcomes relevant to the review: hypotension, bradycardia
Notes	Funding/declarations of interest: not reported Study dates: not reported Notes: 3 participants were withdrawn from the study before initiation of treatment. Study authors did not report to which group these participants were allocated. We did not include these participants in the number randomized we combined data for both esmolol groups in analysis
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not specfied
Allocation concealment (selection bias)	Unclear risk	Not specified
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Anaesthetists were blinded to the type of drug
Blinding of outcome assessors (detection bias) All outcomes	Unclear risk	Not specified
Incomplete outcome data (attrition bias) All outcomes	Low risk	3 participants were withdrawn before initiation of study intervention. No other 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	High risk	Participants in either group were treated with esmolol in the event of hypertension, arterial blood pressure and tachycardia. This may influence outcome data for some control group participants