Steinbrook 1997.

Methods	Design: RCT Operative phase: intraoperative Withdrawals: 3/27 (11%) Setting: 1 centre (USA) Sample size: 27 Funding: not stated
Participants	Age (mean): 38 ‐ 54 years Gender (M/F): not stated ASA grade: I ‐ III Surgery type: elective (major intra‐abdominal surgery) Surgery duration: not stated Anaesthesia type: general and epidural
Interventions	Intervention (ABSW): n = 11 Forced‐air warmer (Model 500, Bair Hugger®, Augustine Medical, Inc., Eden Prairie, MN) was employed to maintain oesophageal temperature as close to 37°C as possible + IV fluids were warmed to 37ºC Duration (mean): not stated Body area covered: not stated Control: n = 13 Routine thermal care Co‐interventions: Inspired gases were not heated Room temperature (OR and PACU): 20° ‐ 22ºC
Outcomes	Blood loss (ml) Fluids infused (ml) Shivering (present/absent) Other outcomes reported not included in the review: Opioids (morphine) intraoperative and at PACU
Notes	Comparison 1
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Toss of a coin
Allocation concealment (selection bias)	High risk	No
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not reported
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported
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Incomplete outcome data (attrition bias) All outcomes	Low risk	3 participants were withdrawn from the study because of changes in the protocol
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