Leung 2007.

Methods	Design: RCT Operative phase: intraoperative Withdrawals: no Setting: 1 centre (Hong Kong) Sample size: 60 Funding: not stated
Participants	Age (range): 65 years (64.1/66.1) Gender (M/F): 39/21 Exclusion: pregnancy, core temp ≥ 37.5°C ASA grade: I ‐ III Surgery type: elective laparotomy: Pancreatic (n = 8); Gastric (n = 16); Hepatobiliary (n = 19); Colectomy (n = 13); Abdominal aortic aneurism (n = 3); Cystectomy (n = 1) Surgery duration: > 2 hrs (258/271 mins) Anaesthesia type: general
Interventions	Intervention (ABSW1): n = 30 Upper‐body forced‐air warming (Bair Hugger®, Augustine Medical model 500/OR, Prairie, MN) A cotton blanket was folded once to make 2 layers in thickness, with the forced‐air warming blanket sandwiched between the 2 layers. Duration (mean): 271 minutes. After induction until end of surgery Temperature setting at 43°C Body area covered: Intervention (ABSW2): n = 30 Electric heating pad (Operatherm® 202+ prewarmed gel pad) For the heating‐pad group, the 104 X 45 cm pad was placed on the operating table and a pre‐warmed gel pad was placed on top of it, as suggested by the manufacturer, covered in turn with a sheet. The participant then lay on the hospital bed sheet and a double‐folded cotton blanket was applied to cover the anterior chest and both arms, as for the forced‐air group Duration (mean): 271 mins Temperature setting at 39°C Body area covered: Co‐interventions: All IV fluids were warmed to 37ºC with an infusion warmer Ambient temperature: 21.1° ‐ 22.1 ºC
Outcomes	Thermal comfort (VAS 0 ‐ 10) Shivering (present/absent) Blood loss (ml) Fluids infused (crystalloids; colloids) (ml) Transfusion (RBC) (mL) Other outcomes reported not included in the review: % participants with hypothermia
Notes	Comparison 2
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomly allocated by drawing lots
Allocation concealment (selection bias)	Unclear risk	Not reported
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	All randomized participants were analysed
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