For a study, researchers sought to find out how blood gas exchange changes during the first hour of life in newborns with a congenital diaphragmatic hernia (CDH). A prospective observational cohort study was conducted on 34 newborns with CDH during the first hour of life to evaluate arterial blood gas (ABG) samples and ventilator support. Infants were classified as having mild, moderate, or severe CDH. The initial ABG was compared to umbilical cord ABGs, and response to intervention was assessed on successive ABGs in newborns with varying degrees of CDH severity.

Infants were intubated in a median time of 120 seconds (range 50-240 seconds), and ABGs were acquired at a median time of 6 minutes (IQR 4, 8 minutes), 16 minutes (IQR 13.5, 22.5 minutes), and 60 minutes (IQR 56, 64 minutes). When compared to the cord ABG, the mean partial pressure of carbon dioxide (PaCO2) increased from 49.8 mm Hg to 82.1 mm Hg, the mean base deficit reduced from −2.2 to −7.3, and the mean pH increased from 7.298 to 7.060. With ventilator modifications, the second mean PaCO2 fell to 76.7 mm Hg, and the third mean PaCO2 fell to 48.5 mm Hg. PaCO2 rose suddenly in all CDH severities when stratified, remained elevated in moderate and severe CDH, and improved in all severities by 60 minutes following delivery.

In babies with CDH, gas exchange is significantly disrupted in the first hour of life, with a sudden start of acidemia and a mixed respiratory and metabolic acidosis. Therefore, early deployment of proper cardiopulmonary support may help to more prompt gas exchange stabilization.