End-tidal carbon monoxide levels in prematurely born infants developing bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is associated with an early inflammatory response that persists after the first week of life. Inflammatory mediators can induce hemoxygenase-1 with a consequent increase in carbon monoxide (CO) production. End-tidal CO (ETCO) levels would be elevated in infants developing BPD. Serial measurements of ETCO levels were attempted on d 3, 5, 7, 14, 21, and 28 in 50 prematurely born infants (median gestational age 29 wk). Fourteen infants developed BPD [oxygen dependent beyond 36 wk post-menstrual age (PMA)] and had higher ETCO levels compared with the rest of the cohort on d 7, 14, 21, and 28. On d 14, the mean (SD) ETCO levels of the BPD group were 3.19 (1.11) ppm and 1.43 (0.61) ppm in the non-BPD group (p<0.001). An ETCO level on d 14>2.15 ppm had a sensitivity of 80% and specificity of 92% in predicting oxygen dependency at 36 wk PMA. Measurement of ETCO levels in prematurely born infants may be useful in the prediction of BPD.