Pu 2014.

Methods	Design: RCT Operative phase: intraoperative Withdrawals: none Setting: 1 centre (China) Sample size: 110 Funding: In part by the Science and Technology Commission of Shanghai Jiao Tong University (Project Jyh0913)
Participants	Age (mean): 68 yrs Gender (M/F): 60/50 ASA grade: I ‐ II Surgery type: open and laparoscopic surgery for gastrointestinal tumours Surgery duration (mean): > 2 hrs (146/149 mins) Anaesthesia type: general
Interventions	Intervention (ABSW): n = 55 Forced‐air warming disposable underbody warming blanket (Model 545, 585, 3MTM Bair Hugger®, Saint Paul, MN, USA) with reusable forced‐air warming system (Model 750, 3MTM Bair Hugger®) for either horizontal position or lithotomy position Temperature set at: up to 41ºC Body area covered: legs up to the pubis Control: n = 55 Warm quilt Co‐interventions: The CO₂ used for maintaining pneumoperitoneum was not prewarmed (room temperature) and the fluids intake during the operation were room‐temperature crystalloid solutions Room temperature: 22° ‐ 24 ºC
Outcomes	Fluids infused (total) (ml) Blood loss (ml) Wound infection Shivering (VAS 0 ‐ 10) Pain (VAS 0 ‐ 10) Other outcomes reported not included in the review: Intraoperative complications: haemorrhage (< 150 mL / > 150 mL); organ injury Postoperative complications Postoperative haemoglobin Coagulation markers at various time points before and during surgery and at the end of surgery (prothrombin time, activated partial thromboplastin time and thrombin time)
Notes	Comparison 1
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Open‐label ('risk of bias' judgement depending on the nature of the outcome)
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Open‐label ('risk of bias' judgement depending on the nature of the outcome)
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