Percutaneous respiration in the newborn infant. Effect of gestation and altered ambient oxygen concentration.

Percutaneous respiration was studied in 32 newborn infants between 25 and 41 weeks gestation, using a closed skin cell attached to the abdomen. Gas exchange rates in the first few days of life were 6-11 times faster in infants below 30 weeks gestation than in term infants (mean O2 absorption 25.0 vs. 206.5 ml/m2/h, and CO2 excretion 26.0 vs. 294.6 ml/m2/h), but rates were similar by 3 weeks of age. Increasing the ambient oxygen concentration resulted in a non-linear increase in oxygen absorption, particularly in the most immature infants. Below 30 weeks gestation, O2 absorption increased from a mean of 206.5 ml/m2/h in air, to 357.2 ml/m2/h in 40% oxygen and 573.5 ml/m2/h in 90% oxygen. We estimate that an infant below 30 weeks gestation, nursed naked in 90% oxygen, would obtain up to 20% of resting oxygen requirements percutaneously.