Carboxyhemoglobin as biomarker of prematurity complications

Background: Carboxyhemoglobin (COHb) is considered a biomarker of oxidative stress and previous studies suggest a correlation between its blood level and prematurity complications. Our aim in this study was to assess the correlation between COHb levels and the risk for bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), and retinopathy of prematurity (ROP). Methods: We retrospectively studied 178 preterm infants with gestational age of 27.0 +/- 1.5 weeks, among which 121 (68 %) had BPD, 43 (24 %) IVH, and 33 (19 %) ROP. COHb levels measured during the first seven days of life were recorded. Results: Logistic regression analysis showed that higher levels of COHb on the seventh day of life increases the risk for moderate-to-severe BPD (OR 4.552, 95 % Cl 1.220-16.997; P = 0.024), while higher levels of COHb on the fourth day of life increases the risk for grade 2-4 IVH (OR 5.537, 95 % Cl 1.602-19.134; P = 0.007). Conclusions: COHb measured in the first week of life can contribute to predicting the risk for BPD and IVH, but not for ROP, in very preterm infants. Since COHb can be readily measured, its assessment can be useful in clinical practice for early identification of preterm infants at high risk for oxidative stress related complications.