Meftahuzzaman 2014.

Methods	RCT, parallel group
Participants	Total number of randomized participants: 60 Inclusion criteria: male or female; weighing 35‐60 kg; 15‐55 years of age; ASA I or II; scheduled for elective surgical procedures Exclusion criteria: predicted difficult intubation; hypertension; ischaemic heart disease; compensatory tachycardia; baseline HR < 60 bpm or SBP < 100 mmHg; chronic obstructive airway disease; taking medication with cardiovascular effects Type of surgery: elective surgery (type not specified; we assumed non‐cardiac) Baseline characteristics Intervention group (labetalol) Age, mean (SD): 38.5 (± 11.23) years Gender, M/F: 15/15 Control group (placebo) Age, mean (SD): 35.33 (± 10.41) years Gender, M/F: 15/15 Country: Bangladesh Setting: single centre; hospital
Interventions	Intervention group (labetalol) Randomized, n = 30; losses = 0; analysed, n = 30 (use of ITT analysis not reported) Details: 0.25 mg/kg labetalol diluted with 10 mL normal saline, IV; 3 min prior to intubation over a period of 30 seconds Control group (placebo) Randomized, n = 30; losses = 0; analysed, n = 30 Details: 10 mL normal saline, given same as the intervention group
Outcomes	Outcomes measured/reported by study authors: haemodynamic variables; bradycardia (HR < 50 bpm) Outcomes relevant to the review: bradycardia
Notes	Funding/declarations of interest: not reported Study dates: January 2012‐June 2013 Note: study included an additional arm (fentanyl), which we did not include in the review
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not specified
Allocation concealment (selection bias)	Low risk	Use of sequentially, numbered, sealed envelopes
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Described as placebo‐controlled double‐blinded study, and therefore we assumed that personnel were blinded
Blinding of outcome assessors (detection bias) All outcomes	Unclear risk	No 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