Gibson 1988.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 40 Inclusion criteria: neurosurgical patients who exhibited at least 20% increase in SBP above average ward pressure on emergence from anaesthesia Exclusion criteria: unsuitable for beta‐blocker treatment, HR < 60 bpm, atrioventricular block, sick sinus syndrome, prior evidence of congestive heart failure, history of bronchospasm or asthma, impaired renal or hepatic function, receiving beta‐blockers or calcium channel blockers within 4 h of entry into study Type of surgery: different neurosurgical interventions Baseline characteristics Intervention group (esmolol) Age, mean (SD): 51.2 (± 17.5) years Gender, M/F: 15/6 History of hypertension, n: 8 Control group (placebo) Age, mean (SD): 51.7 (± 15.7) Gender, M/F: 8/11 History of hypertension, n: 6 Country: USA Setting: single centre; hospital
Interventions	Intervention group (esmolol) Randomized, n = 21; losses = 0; analysed, n = 21 (use of ITT analysis was not reported) Details: during anaesthesia, continuous infusion with a loading dose of esmolol 40 mg/min for 4 min, followed by infusion rate of 24 mg/min. Continued until 10 min after extubation Control group (placebo) Randomized, n = 19; losses = 0; analysed, n = 19 Details: given same as intervention
Outcomes	Outcomes measured/reported by study authors: haemodynamic variables, hypertension, hypotension (not defined), bradycardia (not defined); nausea and vomiting Outcomes relevant to the review: bradycardia and hypotension (see notes below)
Notes	Funding/declarations of interest: not reported Study dates: not reported Note: we did not include data for bradycardia and hypotension in analysis because we could not be certain whether these outcomes were measured in both groups. Study authors reported that 2 participants in the esmolol group had mild to moderate hypotension that required discontinuation of treatment, and one participant in the placebo group experienced bradycardia
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
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	High risk	An antihypertensive agent (hydralazine or labetalol) was given intraoperatively to participants in either group to control BP. It is unclear how many participants in the control group received labetalol, which may influence outcome data