Prevention of water and heat losses from the exposed intestine.
Intestinal exposure results in increased evaporative water and heat losses. The losses are inversely proportional to ambient relative humidity. The purposes of this study were to quantitate water and heat losses from the exposed intestine and to test the plastic bag as a device to reduce these losses. Seventeen piglets were studied. Over a 2 hr period, evaporated losses were considerable--water 96 ml/m2 and heat 56 cal/m2. Prior to placing the intestine in a plastic nonpermeable bag, the exposed intestine lost 54.8 g/m2/hr at an ambient relative humidity of 41.3%. When the intestine was placed in a plastic bag, the relative humidity within the bag rose rapidly to 92.3% and evaporative water and heat losses fell to 0. It was concluded that placing the intestine in a plastic bag allowed the water vapor that escaped from the bowel surface to accumulate about the intestine, raising the relative humidity close to 100% and thereby markedly reducing further evaporation and water and heat losses.