Effects of Active Heating Methods on Body Temperature, Shivering, Thermal Comfort, Pain, Nausea and Vomiting During General Anesthesia: A Randomized Controlled Trial.

To investigate the effect of forced-air warming and heated intravenous (IV) and irrigation fluids alone and in combination on body temperature, shivering, thermal comfort, pain, nausea and vomiting in adult patients undergoing surgery under general anesthesia in a prospective, four-group, randomized controlled trial. After induction of anesthesia, 120 patients were divided into the following groups: patients warmed with forced-air warming (n = 30), patients receiving warmed IV and irrigation fluid (n = 30), patients receiving warmed IV and irrigation fluid with forced-air warming (n = 30), and the control group without any intervention (n = 30). Body temperature, shivering, thermal comfort, pain, nausea and vomiting were monitored in the first 24 hours after surgery. The general characteristics of the groups, mean body temperature, length of stay, ambient temperature, and duration of surgery in the preoperative waiting unit were similar (p > 0.05). Compared with the other groups, patients in the control group had a significant decrease in body temperature from the 30th minute during surgery (p < 0.001), lower body temperature in the first 2 hours and thermal comfort in the first three hours after surgery (p < 0.01), and higher shivering levels in the first hour after surgery (p < 0.01). There was no significant difference between the groups in terms of postoperative pain, nausea and vomiting (p > 0.05). The study findings showed that normothermia was maintained in all three intervention groups during the surgery and in the first 24 hours after surgery. Moreover, postoperative thermal comfort increased and shivering levels decreased compared with the control group, but pain, nausea and vomiting levels were not affected. The study was registered on ClinicalTrials.gov (NCT04907617).