Maintaining intraoperative normothermia reduces blood loss in patients undergoing major operations: A pilot randomized controlled clinical trial

Abstract

Background: Inadvertent intraoperative hypothermia (core temperature<36°C) is a common but preventable adverse event. This study aimed to determine whether active intraoperative warming reduced bleeding in patients undergoing major operations: open thoracic surgery and hip replacement surgery. Methods/Design: The study was a pilot, prospective, parallel two-arm randomized controlled trial. Eligible patients were randomly allocated to two groups: passive warming (PW), with application of a cotton blanket (thermal insulation), or active warming (AW), with a forced-air warming system. The primary endpoint was intraoperative blood loss, and secondary endpoints were surgical-site infection, cardiovascular events, and length of stay in the post-anesthesia care unit, intensive care unit, and hospital. Results: Sixty-two patients were enrolled. Forced-air active warming maintained intraoperative normothermia in all AW subjects, whereas intraoperative hypothermia occurred in 21/32 (71.8%) of PW patients (p=0.000). The volume of blood loss was more in the PW group (682±426ml) than in the AW group (464±324ml) (p<0.021), and the perioperative hemoglobin value declined more in the PW group (28.6±17.5g/L) than in the AW group (21.0±9.9g/L) (p=0.045). However, there were no difference in other clinical outcomes between two groups. Conclusion: Intraoperative active warming is associated with less blood loss than passive warming in open thoracic and hip replacement operations in this pilot study.