Incidence and Risk Factors of Intraoperative Hypothermia in Adult Patients After Protocol Implementation

Inadvertent intraoperative hypothermia, defined as a core body temperature below 36 C, is one of the most common complications in patients undergoing anesthesia. This condition is strongly associated with several adverse clinical outcomes, including increased risk for surgical site infections, delayed wound healing, prolonged recovery and hospitalization, coagulopathy, and increased requirements for blood transfusion. Many risk factors are associated with inadvertent intraoperative hypothermia including: high ASA physical status, age >65-year, general anesthesia combined with neuraxial anesthesia, longer anesthesia duration, emergency major surgery, intraoperative blood loss and intravenous fluid volume received.

Despite the existence of international recommendations from organizations like the American Society of Anesthesiologists (ASA) and the National Institute for Health and Care Excellence (NICE)-which recommend interventions including active warming, using warm irrigation fluid, and continuous temperature monitoring to minimize the risk of intraoperative hypothermia, hypothermia remains prevalent in many settings. At Siriraj Hospital, a previous study revealed a high incidence rate of 74.4%, with only 16.3% of patients receiving intraoperative temperature monitoring. In response to these findings, Siriraj Hospital implemented a standardized perioperative temperature management guideline (protocol) in July 2024. This protocol recommends pre-warming and active warming strategies to mitigate extrinsic risk factors, such as low operating room temperatures and the administration of cold intravenous fluids.

However, it remains to be evaluated whether the implementation of this protocol has led to a meaningful change in clinical practice. The primary concern is whether the adherence to temperature monitoring for surgeries exceeding one hour has improved from the historical rate of 16.3%, and subsequently, whether this has resulted in a decreased incidence of hypothermia. Furthermore, intrinsic patient factors-such as age, Body Mass Index (BMI), and surgical complexity-continue to be potential variables that the protocol alone may not fully address.

To date, the real-world impact of this specific protocol on reducing hypothermia has not been formally evaluated. Therefore, this study is essential to evaluate the effectiveness of the Siriraj temperature management protocol. The findings will not only determine the current intraoperative monitoring rate and the incidence of hypothermia but also identify significant intrinsic risk factors that persist despite standardized care. This information will be vital for further quality improvement and ensuring patient safety in the perioperative setting at Siriraj Hospital.