Wet forced‐air warming blankets are ineffective at maintaining normothermia

Abstract

Forced-air warming systems have proven effective in preventing perioperative hypothermia. To date, reported adverse events relate primarily to overheating and thermal injuries. This study uses a simple model to show that forced-air warming blankets become ineffective if they get wet. Temperature sensor probes were inserted into three 1-liter fluid bags. Group C bags served as the control. Groups D (dry) and W (wet) bags were placed on Bair Hugger(R) Model 555 (Arizant Healthcare, Inc., Eden Prairie, MN, USA) pediatric underbody blankets. The warming blanket for Group W bags was subsequently wet with irrigation fluid. Temperature was documented every 5 min. This model was repeated two times for a total of three cycles. Statistical analysis was performed using anova for repeated measures. Starting temperatures for each model were within a 0.3 degrees C range. Group C demonstrated a steady decline in temperature. Group D maintained and slightly increased in temperature during the observation period, while Group W exhibited a decrease in temperature at a rate similar to Group C. These results were significant at P < 0.005. A wet forced-air warming blanket is ineffective at maintaining normothermia. Once wet, the warming blanket resulted in cooling similar to the control group.