Early Abnormalities in Gas Exchange in Infants with Congenital Diaphragmatic Hernia.

<bold>Objective: </bold>To determine how blood gas exchange is altered during the transition in the first hour of life in infants with congenital diaphragmatic hernia (CDH).<bold>Study Design: </bold>This was a prospective observational cohort study evaluating arterial blood gas (ABG) samples and ventilator support in 34 infants with CDH in the first hour of life. Infants were stratified into mild, moderate, and severe CDH. The first ABG was compared with the umbilical cord ABGs and response to intervention evaluated on subsequent ABGs among infants with different CDH severities.<bold>Results: </bold>Infants were intubated at a median of 120 seconds (range 50-240 seconds) and ABGs obtained at a median of 6 minutes (IQR 4, 8 minutes), 16 minutes (IQR 13.5, 22.5 minutes), and 60 minutes (IQR 56, 64 minutes). Compared with the cord ABG, first ABG mean partial pressure of carbon dioxide (PaCO2) increased from 49.8 mm Hg to 82.1 mm Hg, mean base deficit decreased from -2.2 to -7.3, and mean pH from 7.298 to 7.060. With ventilator adjustments, second mean PaCO2 decreased to 76.7 mm Hg and third mean PaCO2 48.5 mm Hg. When stratified, with all CDH severities PaCO2 increased abruptly, remained elevated in moderate and severe CDH, and improved in all severities by 60 minutes after delivery.<bold>Conclusions: </bold>Gas exchange is markedly altered in the first hour of life in infants with CDH with abrupt onset of acidemia and a mixed respiratory and metabolic acidosis. Early implementation of adequate cardiopulmonary support may contribute to more timely stabilization of gas exchange. [ABSTRACT FROM AUTHOR]