Unal 2008.

Methods	RCT, parallel design
Participants	Total number of randomized participants: 45 Inclusion criteria: ASA status I or II; scheduled for lumbar disc surgery Exclusion criteria: pregnant women; HR < 60 bpm; SBP < 100 mmHg; serious hepatic, renal and cardiovascular diseases; congestive heart failure; atrioventricular block; sick sinus syndrome; drug allergy and past history of beta‐blocker intolerance; bronchospasm; asthma; COPD; haemotological disorders; receiving beta‐blockers and calcium channel blockers Type of surgery: lumbar disc surgery Baseline characteristics Intervention group (esmolol 0.1 mg/kg/min) Age, mean (SD): 50.3 (± 17.1) years Gender, M/F: 7/8 ASA status I/II: 8/7 Intervention group (esmolol 0.2 mg/kg/min) Age, mean (SD): 48.1 (± 16.2) years Gender, M/F: 7/8 ASA status I/II: 6/9 Control group (placebo) Age, mean (SD): 50.3 (± 12.2) years Gender, M/F: 8/7 ASA status: 9/6 Country: Turkey Setting: single centre; hospital
Interventions	Intervention group (esmolol 0.1 mg/kg/min) Randomized, n = 15; losses = 0; analysed, n = 15 Details: bolus dose 0.5 mg/kg over 4 min, at the end of surgery, before extubation. Then infusion of esmolol 0.1 mg/kg/min continued until 10 min after extubation Intervention group (esmolol 0.2 mg/kg/min) Randomized, n = 15; losses = 0; analysed, n = 15 Details: bolus dose 0.5 mg/kg over 4 min, at the end of surgery, before extubation. Then infusion of esmolol 0.2 mg/kg/min continued until 10 min after extubation Control group (placebo) Randomized, n = 15; losses = 0; analysed, n = 15 Details: 0.9% saline, given same as the intervention groups
Outcomes	Outcomes measured/reported by study authors: haemodynamic variables, hypotension, hypertension Outcomes relevant to the review: hypotension
Notes	Funding/declarations of interest: not reported Study dates: not reported Note: we combined both esmolol groups in analysis
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	Unclear risk	Quote: "Esmolol and SP (serum physiological) solutions were prepared without the knowledge of the person who would keep the records" Comment: it was unclear whether 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	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