CARBON-MONOXIDE DIFFUSING-CAPACITY IN NEWBORN-INFANTS

In order to test the role of diffusing capacity in determining the arterial O2 tension of newborn infants, pulmonary diffusing capacity for CO (DLCO) was measured in 21 healthy infants ranging in birth weight from 765-4720 g. DLCO in infants without respiratory distress correlated well with lung volume (r = 0.76, P < 0.001). A smaller correlation (r = 0.39, P < 0.01) was obtained between DLCO and arterial O2 tension. DLCO per unit volume of lung was similar when healthy premature infants, full term infants and normal adults were compared. The wide range of normal values obtained in resting infants and the lack of correlation with arterial O2 tensions were similar to observations made in adults.