Elevated carbon dioxide tension as a predictor of subsequent adverse events in infants with bronchopulmonary dysplasia.

Infants with bronchopulmonary dysplasia (BPD) are at risk for numerous complications following discharge from the Neonatal Intensive Care Unit (NICU). Few studies have evaluated risk factors for adverse events (AE). This retrospective study provided an initial evaluation of the use of capillary carbon dioxide (PCO2) tension as a predictor of infants with BPD at increased risk for AE. PCO2 was compared in patients who suffered, or avoided, severe AE, defined as pulmonary hypertension, death, or subsequent reintubation or tracheostomy for respiratory illness. One hundred twelve consecutive patients followed at the BPD clinic were evaluated, and data from 104 subjects were suitable for analysis. Mean PCO2, obtained shortly before or after discharge from NICU, was 47.2 mmHg (range, 31-83). PCO2 was significantly higher in patients who required reintubation and ventilation (54.7 vs. 46.7, p < 0.04). No cutoff value of PCO2 clearly distinguished patients with subsequent AE. PCO2 was not significantly higher in the group of patients who had a severe AE than in the group of patients who did not have a severe AE, but logistic regression showed a significant association between PCO2 and risk of both severe AE (p = 0.018), and readmission to hospital (p = 0.038). An elevated PCO2 is associated with an increased risk of AE, including reintubation, and readmission to hospital, in infants with BPD. Patients with an elevated discharge PCO2 may require closer monitoring during followup. Prospective studies will be needed to confirm these observations.