Transient respiratory distress syndrome in the newborn.

the infant had been breathing 100/o 02 by mask at 10 I./min. for 15 minutes, the initial arterial sample was obtained. Subsequently, if the infant's condition permitted, arterial Po2 was measured, with the infant breathing room air for 15 minutes. Blood was analysed for pH and carbon dioxide tension (Paco.,) by the interpolation method (Astrup, J0rgensen, Siggaard Andersen, and Engel, 1960) and the base deficit (negative base excess) calculated from a nomogram (Siggaard Andersen, 1962). The base deficit values were corrected for oxygen saturation and the effect of increases in PaCo2 (Dell, Engel, and Winters, 1966). The arterial oxygen tension (Pao2) was determined with a modified Clark electrode (Radiometer-Beckman) calibrated with tonometred water and maintained at 38C. All readings were corrected for temperature differences and