Propofol Linearly Reduces the Vasoconstriction and Shivering Thresholds

Abstract

Comment Intraoperative hypothermia is relatively common and is associated with the potential for increased postoperative morbidity owing to hypoxemia, shivering and myocardial ischemia. The effects of intravenous anesthetics on thermoregulatory responses in humans has not been well quantified. Volatile anesdietic agents increase the core temperature required to trigger sweating and decrease the core temperature required to trigger vasoconstriction. The Departments of Anesthesiology at the University of California, San Francisco, and the Department of Anaesthesia, Royal Melbourne Hospital, Australia, have cofounded a Thermoregulation Research Laboratory. A new volunteer model was developed in which thermal manipulations were restricted to insensate skin, and sensate skin temperature was controlled. The first report from tins group confirmed that propofol caused a dose-dependent decrease in the thermoregulatory threshold for vasoconstriction. In contrast to volatile anesthetics, propofol did not alter the sweating threshold.1 Although the technique used in the initial study proved useful, it was limited by the need for epidural anesthesia, insertion of central venous cannulas, and the administration of large fluid volumes. The model the investigators from the