Table 1. Characteristics of included trials.

Trial	Patients	Warming technique	Type of surgery	Outcome measurements
Melling and Leaper18	45	Non-contact radiant heat system	General surgery	Pain and wound infection
Kim et al.19	40	Forced warming blanket	Cardiothoracic	Temperature
Cavallini et al.20	76	Forced warming blanket	Plastic surgery	Temperature, coagulation
Zhao et al.21	40	Forced warming blanket	Abdominal surgery	Temperature, blood loss, shivering, extubation time
Scheck et al.22	30	Carbon-fiber warming blanket	Trauma patients	Temperature
Xu et al.23	40	Forced warming blanket and fluid warming device	Abdominal surgery	Temperature, blood loss, shivering, extubation time
Vanni et al.24	30	NA	Abdominal surgery	Temperature
Persson and Lundberg25	59	Forced warming blanket	Gynecological	Temperature, pain
Melling et al.14	421	Forced warming blanket	General surgery	Wound infection
El-Rahmany et al.26	149	Forced warming blanket	Cardiothoracic	Temperature, cardiovascular vital signs
Bock et al.27	40	Forced warming blanket	Abdominal Surgery	Temperature, blood loss, stay, cost, transfusion.
Wongprasartsuk et al.28	26	Forced warming blanket	Orthopedic	O2 consumption, CO2 production, pain, temperature
Frank et al.12	300	Forced warming blanket	Vascular, thoracic and abdominal	Temperature, ischemic heart disease, cardiac arrest
Schmied et al.11	60	Forced warming blanket	Orthopedics	Blood loss, transfusions
Kurz et al.29	200	Forced warming blanket	Colorectal surgery	Wound infection, stay
Frank et al.30	74	Forced warming blanket	Vascular, thoracic and abdominal	Neuroendocrine response, temperature, blood pressure, pulse rate
Frank et al.31	100	NA	Vascular surgery	Temperature, cardiac stress
Camus et al.32*	22	Forced warming blanket	Abdominal Surgery	Temperature, shivering
Camus et al.32†	33	Forced warming blanket	Abdominal surgery	Temperature, shivering

*limb a of trial; †limb b of trial. NA = not available. Heating technique was not mentioned in the trial but this group was definitely provided with perioperative warming.