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Comparison of forced-air warming and resistive heating
1Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Goettingen, Goettingen, Germany.
Background:
Perioperative hypothermia is common during anesthesia and surgery and is accompanied by several complications. Forced-air warming is recognized as an effective procedure to prevent hypothermia. The aim of this study was to compare a resistive heating device with a forced-air warming device.
Methods:
Prospective randomized trial.
Setting:
heat transfer laboratory of a University hospital.
Participants:
six healthy volunteers.
Interventions:
warming with a forced-air warming device (BairHugger 505 and Upper Body Blanket 522; Arizant Healthcare Inc., Eden Prairie, MN, USA) or a resistive heating device (Geratherm Adult system; Geratherm Medical AG, Geschwenda, Germany).
Measures:
heat transfer was measured with 11 calibrated heat flux transducers on the upper body. Additionally, blanket and skin temperatures were measured. The t-test for matched pairs was used for statistical evaluation.
Results:
Skin temperature under the covered surface was not statistically different between the two groups (37.3+/-0.2 degrees C in the forced-air warming group and 37.8+/-0.2 degrees C in the resistive heating group). In contrast, blanket temperature (40.3+/-0.6 degrees C vs 38.1+/-0.4 degrees C, P=0.002) and heat transfer (13.2+/-3.6 W vs 7.8+/-1.9 W, P=0.048) were significantly higher in the resistive heating group.
Conclusion:
Heat transfer in the resistive heating system was significantly greater than that of the forced-air warming system.
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