Basic Principles and Consequences of Perioperative Hypothermia

PerioperativePerioperative hypothermia is common with an incidence ranging between 20 and 70%, and is conventionally defined by a body core temperature below 37.0 °C. Even severe intraoperative hypothermia was common during the previous centuries, as intraoperative warming was rare, and the negative impact of hypothermia was not fully understood yet. In the 1980s and 1990s, intraoperative hypothermia was identified as a significant and independent contributor to perioperativePerioperative morbidity. PerioperativePerioperative hypothermia causes impaired pharmacokineticsPharmacokinetics, surgical site infections, blood loss and coagulopathyCoagulopathy, transfusionTransfusion requirements, thermal discomfort, prolonged recovery, and prolonged duration of hospitalization. For many years, an intraoperative target threshold of 36 °C was considered effective, although only based on limited evidence. Most recent findings by a large RCT highlight that maintaining the patient in a slight hypothermic state at ≥ 35.5 °C is safe and won’t affect patient outcomes. Core temperature should be measured in all patients having general or regional anesthesia lasting more than 30 minutes. Anesthesiologist should aim to maintain a core temperature ≥ 35.5 °C by actively (re-)warming patients. Several warming devices are commercially available, including active skin warming by forced air as the most commonly used, efficient, inexpensive, and easy-to-use technique for the majority of patients and surgeries.