Study objective: To evaluate the efficacy of a forced-air warmer during spinal surgery for correction of scoliosis in children.
Design: Prospective randomized study (group allocation based on the availability of the warming device).
Setting: Children's teaching hospital.
Patients: 51 ASA physical status I and II children (mean age, 15 years; mean weight, 45 kg) scheduled for posterior spinal fusion with general anesthesia.
Interventions: Study group (warmed; n = 26)--legs covered with the forced-air warmer (Bair Hugger, Augustine Medical, Inc., Eden Prairie, MN) after installation of the patient in prone position--versus control group (n = 25)--400W heat lamp placed over the head during surgery as is usually done in our institution.
Measurements and main results: Rectal temperature was taken every 15 minutes during surgery and during the first 2 hours in the recovery room. Time required for the wake-up test, time to extubation, and blood loss also were noted. Temperature profiles were very different in the 2 groups. In the control group, rectal temperature decreased during the first 180 minutes to a minimum of 34.8 degrees C +/- 0.6 degrees C, followed by a slow rewarming phase. In the warmed group, the lowest temperature (35.6 degrees C +/- 0.5 degrees C) was recorded 45 minutes after placement of the forced-air warmer, followed by an effective warming phase. At the end of surgery, temperature was significantly higher in the warmed group than in the control group (36.5 degrees C +/- 0.8 degrees C vs. 35.4 degrees C +/- 0.9 degrees C). However, time required for the wake-up test, time to extubation, and blood loss did not differ between groups.
Conclusion: The forced-air warmer (Bair Hugger) is effective during spinal surgery, although only about 20% of body surface area can be covered.