BAIR-HUGGER FORCED-AIR WARMING MAINTAINS NORMOTHERMIA MORE EFFECTIVELY THAN THERMO-LITE INSULATION

Study Objective: To compare the ability of forced-air warming and reflective insulation to maintain intraoperative normothermia. Design: Prospective, randomized clinical trial. Setting: Operating rooms of a general hospital. Patients: 20 ASA physical status I and II patients undergoing elective total hip arthroplasty. Interventions: Patients were randomly assigned to be warmed intraoperatively using forced-air or reflective insulation. Inspired gases were conditioned using a heat-and-moisture exchanger in both groups, and infused intravenous fluids were warmed to 37 degrees C. Measurements and Main Results: Distal esophageal (core) temperatures decreased appoximately 0.5 degrees C in both groups during the first 45 minutes of anesthesia. Subsequently core temperatures increased slightly in the patients given forced-air warming. In contrast, core temperatures continued to decrease in patients covered with reflective insulation. After 135 minutes of anesthesia, core temperatures were 36.4 +/- 0.6 degrees C (mean +/- SD) in the forced-air group but only 35.4 +/- 0.6 degrees C in the insulated group (p < 0.01, unpaired t-test). These data indicate that forced-air warming is superior to reflective insulation. Conclusion: Reflective insulation was unable to maintain intraoperative normothermia during total hip, arthroplasty. Active warming, such as that provided by forced air was required to prevent hypothermia.