Randomised controlled trials (RCTs) were eligible for inclusion if they compared active cutaneous warming systems with forced warm air, during surgery, for patients aged 18 years or older, who were undergoing elective surgery. Trials of warming before anaesthesia and those of induced hypothermia were excluded. The outcome had to be the maintenance of body temperature or the prevention of hypothermia.
In the included trials, seven cutaneous warming systems were assessed, and compared with various forced-air systems. Participants underwent various types of surgery, including off-pump coronary artery bypass, laparoscopic cholecystectomy, transurethral resection of the prostate, liver transplantation, abdominal hysterectomy, total knee replacement, hip replacement, and knee arthroplasty; other surgeries were reported in the paper. In most trials general anaesthesia was used, but in some anaesthesia was spinal, epidural or mixed..
It was unclear how many reviewers selected trials for inclusion..