Transient Respiratory Distress Syndrome in the Newborn*

The variable duration and severity of the respiratory distress syndrome (RDS) make it difficult to assess any therapeutic regime. We have observed 12 infants who at age 4 hours had clinical and biochemical findings indicative of moderate to severe respiratory distress syndrome but who improved rapidly with a standard therapeutic regime, their respiratory distress disappearing or becoming minimal during the first day of life. We describe the clinical, acid-base, and blood-gas course of these infants. For comparison, we also studied a group of 19 distressed premature newborns who initially manifested a similar clinical and bio-chemical picture, but in whom the respiratory distress syndrome persisted beyond age 30 hours despite the same therapeutic regime. For the purposes of comparison, we refer to those infants with minimal or no respiratory distress at age 18 hours as the transient respiratory distress syndrome group (TRD), and those whose respiratory distress persisted beyond age 30 hours as the moderate-severe respiratory distress syndrome group (RDS). (It happened that there were no infants whose respira-tory distress resolved between 18 and 30 hours of age.) Procedures Jnd Methods Infants who manifested idiopathic respiratory distress were clinically evaluated on the basis of a scoring system given in Table I. This scoring system, 0 to 10, has significant linear correlation with the alveolar-arterial Po2 gradient, arterial hydrogen ion concentration, and Paco2 (Downes, Vidyasagar, Morrow, and Boggs, 1967). If, over a 2-hour period, an infant maintained a score of 4 or more, and other causes of respiratory distress were not evident, a presumptive diagnosis of idiopathic respiratory distress syndrome was made. Umbilical artery catheterization was then performed and the catheter inserted 10 to 14 cm., depending on the length of the infant, so that its distal tip was in the thoracic aorta below the ductus arteriosus (Dunn, 1966). Afte