Inada 1989.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 30 Inclusion criteria: adults, 21‐71 years of age, scheduled for elective surgery under GA with tracheal intubation Exclusion criteria: congestive heart failure; unstable angina; bronchospastic disease on bronchodilators; atrioventricular block; severe hepatic dysfunction; ASA physical status IV; concurrent alpha‐ or beta‐adrenergic drug administration Type of surgery: elective surgery (type not specified ‐ we assumed non‐cardiac) Baseline characteristics Intervention group (labetalol 5 mg) Age, mean (SD): 52 (± 5) years Gender, M/F: 5/5 ASA status I/II/III: 2/7/1 History of MI, n: 0 History of hypertension, n: 3 History of COPD, n: 0 Intervention group (labetalol 10 mg) Age, mean (SD): 53 (± 5) years Gender, M/F: 4/6 ASA status I/II/III: 2/7/1 History of MI, n: 0 History of hypertension, n: 2 History of COPD, n: 0 Control group (placebo) Age, mean (SD): 49 (± 5) years Gender, M/F: 55 ASA status I/II/III: 3/7/0 History of MI, n: 2 History of hypertension, n: 1 History of COPD, n: 2 Country: USA Setting: single centre; hospital
Interventions	Intervention group (labetalol 5 mg) Randomized, n = 10; losses = 0; analysed, n = 10 (use of ITT analysis not reported) Details: before induction of GA, 2 mL syringe, labetalol 5 mg Intervention group (labetalol 10 mg) Randomized, n = 10; losses = 0; analysed, n = 10 Details: before induction of GA, 2 mL syringe, labetalol 10 mg Control group Randomized, n = 10; losses = 0; analysed, n = 10 Details: saline, same as the intervention groups
Outcomes	Outcomes measured/reported by study authors: haemodynamic response; dysrhythmias (ventricular begeminy, ventricular extrasystoles); hypotension (not defined); bradycardia (not defined Outcomes relevant to the review: hypotension, bradycardia
Notes	Funding/declarations of interest: drug preparation supported by funds from Shering Corporation Study dates: not reported Notes: in analysis, we combined data from both labetalol groups study included an additional group (lidocaine), which we did not include in this review
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not specified
Allocation concealment (selection bias)	Unclear risk	Not specified
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Randomized, placebo‐controlled, double‐blind trial. Participants received study drugs from "identical syringes" intravenously: content of syringes not predictable in advance
Blinding of outcome assessors (detection bias) All outcomes	Unclear risk	Not specified
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