What determines the efficacy of forced-air warming systems? A manikin evaluation with upper body blankets.

Background: Forced-air warming has gained acceptance as an effective means to prevent perioperative hypothermia. However, little is known about the influence of air flow and air temperature at the nozzle and the influence of heat distribution in the blankets on the efficacy of these systems.

Methods: We conducted a manikin study with heat flux transducers using five forced-air warming systems to determine the factors that are responsible for heat transfer from the blanket to the manikin.

Conductive heat exchange with a gel-coated circulating water mattress.

The use of forced-air warming is associated with costs for the disposable blankets. As an alternative method, we studied heat transfer with a reusable gel-coated circulating water mattress placed under the back in eight healthy volunteers. Heat flux was measured with six calibrated heat flux transducers.