Preductal and postductal transcutaneous oxygen tension measurements in premature newborns with hyaline membrane disease.

Pre- and postductal transcutaneous oxygen tension (tcPO2) was measured in 23 preterm infants with hyaline membrane disease to estimate the degree of right to left ductal shunting. The study was done during the first 24 hours of life and the data were recorded continuously. The studies were 11.9 +/- 4.0- hours long, (mean +/- SD) and the difference between the pre- and postductal tcPO2 (delta TcPO2) was measured every 100 seconds. Of 9,872 determinations, the delta tcPO2 was less than or equal to 15 mm Hg in 90.1%, 16 to 29 mm Hg in 9.3%, and greater than or equal to 30 mm Hg in 0.6%. It was concluded that large differences between pre- and postductal oxygen tension are rare in infants with hyaline membrane disease. The results of this and other published data suggest that it is unlikely that measurement of PaO2 in the descending aorta or tcPO2 below the ductus places infants at an increased risk of having retinopathy of prematurity develop.