1038 REDUCTION OF INSENSIBLE WATER LOSS (IWL) IN PREMATURES UNDER RADIANT WARMERS

Excessive IWL is a well known complication in prematures placed under radiant warmers. A controlled study was therefore undertaken to determine if a plastic dome would be useful in minimizing IWL. Twenty-nine AGA healthy infants with gest. age of 30.9±0.4 wks (mean±S.E.) birth wt. 1.4±.03kg and postnatal age of 8.7±2.1 days were studied. IWL was determined from insensible wt. loss measured on a Potter Bed Balance scale. Water losses from urine and stool were prevented by attaching a plastic pouch to the perineum. IWL was measured under 2 conditions in the same infant: with heat shield (Grp A) and without heat shield (Grp B). Each study period extended for 3 hrs after 30 min. of stabilization. The studies were done in an infra-red radiant warmer (Ohio) with servo-control set at skin temp. of 36.5°C. Skin, rectal, ambient temp. RR, HR and wt. loss were monitored and recorded every 30 min. Total IWL was significantly lower (p<.01) in Grp A as compared with Grp B infants (1.76±.24 vs 2.74±.3 g/kg/hr). RR, HR and skin temp. were similar in both groups. Ambient temp. was higher (p< .01) in Grp A, 34.6±.25°C. than in Grp B, 30.6±.26°C.; rectal temp. was lower (p<.01) in Grp A, 36.7±.13°C. than in Grp B, 37.2±.l°C. The lower IWL of Grp A infants may be due to a smaller skin-air ambient temp. gradient in Grp A than in Grp B. The shield may also alter air flow pattern, resulting in an insulating layer of saturated air over the baby which reduces evaporation from the skin.