Oxygen consumption and insensible water loss in premature infants in single-versus double-walled incubators

Fifteen studies were performed in ten premature infants whose birth weight (mean +/- SD) was 1,444 +/- 250 gm, gestational age 32.7 +/- 1.0 weeks, and postnatal age 10.7 +/- 3.3 days. Each study consisted of three hours simultaneous measurement of insensible water loss and oxygen consumption under two conditions for the same infant: (1) inside a single-walled incubator and (2) inside a double-walled incubator. The double-walled incubator provided significantly (P < 0.001) higher operative temperature and incubator wall temperature than did the single-walled incubator. Infants inside the double-walled incubator had significantly lower (P < 0.01) IWL (30% reduction) and lower (P < 0.05) VO2 (17% reduction) than inside the single-walled incubator--a net caloric saving of 11.8 kcal/kg/day. This saving of energy expenditure may be important in affecting the growth and outcome of the low-birth-weight infants.