Assisted ventilation in infants with meconium aspiration syndrome.

In a retrospective analysis of infants born with meconium staining over an 18-month period at Cook County Hospital, 32 infants met two of the three criteria for the diagnosis of meconium aspiration syndrome: (1) history of meconium in the oropharynx or trachea; (2) clinical evidence of respiratory distress; and (3) x-ray evidence of aspiration pneumonia. Seventeen infants developed respiratory failure; nine of these infants died. One infant without respiratory failure died of sepsis. Analysis of sequential arterial blood pH and gas tension showed that nonsurviving infants had persistently high PCO2 and A-a gradient in spite of initiation of assisted ventilation. These changes seem to be related to severe right-to-left shunting and ventilation perfusion abnormalities. The data further suggest that asphyxia and acidosis occur well before the infant is born and that intrapartum monitoring to recognize fetal asphyxia may help in improving morbidity and mortality from meconium aspiration syndrome.