Warming Intravenous Fluids Reduces Perioperative Hypothermia in Women Undergoing Ambulatory Gynecological Surgery

We evaluated whether warming IV fluids resulted in less hypothermia (core temperature <35.5[degree sign]C) compared with room-temperature fluids. Thirty-eight adult outpatients undergoing elective gynecological surgery of >30 min were randomized to two groups: fluid warming at 42[degree sign]C or control (room temperature fluids at approximately 21[degree sign]C). All patients received general anesthesia with isoflurane, tracheal intubation, standard operating room blankets and surgical drapes, and passive humidification of inspired gases. Tympanic membrane (core) temperatures were measured at baseline and at 15-min intervals after induction. The incidence of shivering and postoperative requirement for meperidine and/or radiant heat were evaluated. Core temperatures were lower in the control compared with the warm fluid group at the end of surgery (35.6 +/- 0.1[degree sign]C vs 36.2 +/- 0.1[degree sign]C; P < 0.05). More patients had final core temperature <35.5[degree sign]C in the control compared with the warm fluid group (35% vs 0%; P < 0.05). There were no differences in time to discharge from the postanesthesia care unit or the incidence of shivering between the groups. We conclude that fluid warming, in conjunction with standard heat conservation measures, was effective in maintaining normothermia during outpatient gynecological surgery; however, there was no improvement in patient outcome. Implications: Women who received IV fluid at body temperature had significantly higher core temperatures during and after outpatient gynecological surgery compared with women who received IV fluids at the temperature of the operating room. (Anesth Analg 1998;87:37-41)