Assessment of the efficiency of warming devices during neonatal surgery
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This study assessed the relative efficiency of different warming devices (surgical sheets covering the body and a tubegauze on the head, forced-air warming, warming mattress) commonly used to prevent body hypothermia during neonatal surgery. Dry heat losses were measured from a thermal manikin, which simulated a low-birth-weight neonate of 1,800 g. The manikin’s surface temperatures (35.8°C) corresponded to those of neonates nursed in closed incubators. Experiments were performed in a climatic chamber at an ambient temperature of 30°C, as commonly found in operating theatres. The supine manikin was naked or covered with operative sheets with a 5×5 cm aperture over the abdomen. Its head could be covered by a tubegauze. Additional warming was provided by conduction through a warming mattress (surface temperature, 39°C) and/or by convection (Bair Hugger, forced-air temperature 38°C). Covering the manikin with surgical sheets decreased the dry heat loss by 10.4 W. Additional forced-air warming was more efficient than the warming mattress to reduce the total dry heat loss (6.8 W vs 2.1 W). Heat losses were reduced by 7.9 W when combining the warming mattress and Bair Hugger. The heat loss from the head of the covered manikin was reduced from 4.5 W to 3.9 W when the head was covered with the tubegauze. Our data indicate that forced-air warming is more effective than conductive warming in preventing neonatal hypothermia during abdominal operations.
KeywordsManikin Neonate Heat exchange Warming device Surgery
The authors thank the Regional Council of Picardy and the French Ministry of Research who supported this study.