Frank 1997.

Methods	Design: RCT Operative phase: intraoperative Follow‐up: Withdrawals: 30/300 (10%) Setting: 1 centre (USA) Sample size: 300 participants > 60 yrs at high risk of cardiovascular events Funding: National Institutes of Health grant GM38177 and Mallinckrodt Medical Inc. Dr Fleisher was supported by the Richard Ross Clinician Scientist Award of The Johns Hopkins University School of Medicine. The ambulatory ECG recorders were donated by Spacelabs Medical Inc
Participants	Age (mean): 71 years Gender (M/F): 167/133 ASA grade: I ‐ IV Surgery type: elective (peripheral vascular, abdominal or thoracic procedures) Surgery duration: > 2 hrs (3.4/3.6 hrs ) Anaesthesia type: general and epidural
Interventions	Intervention (ABSW): n = 142 Forced‐air warming cover (Mallinckrodt Medical®) Duration: not stated Temperature: Set to maintain core temp at 37°C Body area covered: legs and trunk Proportion covered: not stated Control: n = 158 1 layer of paper of surgical field Duration: not stated Control body area covered: not stated Proportion covered: not stated Co‐interventions: IV fluids and blood were warmed, and a heat‐moisture exchanger (Thermovent) was used in the respiratory circuit
Outcomes	All‐cause mortality Cardiac events (electrocardiographic and morbid intraoperative and postoperative events: unstable angina/ischaemia, cardiac arrest, or myocardial infarction) Pain (VAS 0 ‐ 10) 30 and 90 mins postoperatively and the day after surgery Shivering (present/absent) Blood loss (ml) Fluids infused (crystalloids) (ml) Transfusions (RBC) (Units) Other outcomes reported not included in the review: Postoperative ventricular tachycardia Arterial blood pressure > limit Heart rate > 100% Requirement for antihypertensive therapy and drug treatment of tachycardia in the first 24 hours postoperatively Hematocrit (1 day postoperatively) % participants requiring postoperative mechanical ventilation IV morphine requirement Length of stay (ICU, hospital)
Notes	Comparison 1
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomization sequence.
Allocation concealment (selection bias)	Low risk	Opaque, sealed envelopes
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Participants were not informed of their treatment assignment
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Morbid cardiac events were determined by a blinded investigator. All ECGs and enzyme CK data were masked, as well as the Holter tapes
Baseline comparability of groups	Low risk	To a high extent according to Table 1
Co‐interventions equal between groups	Low risk	Yes
Incomplete outcome data (attrition bias) All outcomes	Low risk	30 participants withdrawn because Holter monitoring data were missing (n = 15 hypothermic group, n = 15 in normothermic group)
Selective reporting (reporting bias)	Unclear risk	We did not have access to the protocol, therefore we cannot exclude risk of selective reporting with the information provided
Other bias	Low risk