Differences in arteriovenous carboxyhemoglobin in neonates with noninflammatory pulmonary diseases

To retrospectively examine whether differences in arteriovenous carboxyhemoglobin (a-vCOHb) can be used as a marker for evaluating the severity of neonatal lung disease that develops soon after birth.

The subjects were 129 newborn neonates who were classified into three groups comprising 48 infants with severe respiratory disorder (group S), 46 with mild-to-moderate respiratory disorder (group M), and 35 in a control group without respiratory disorder (group C). Various parameters including COHb were measured using a blood gas analyzer/oximeter at the time of admission, with sampling of arteries and veins performed at short intervals (within 30 min).

The arterial COHb values were significantly higher in group C than in group S. The a-vCOHb values were significantly higher in groups C and M than in group S. This suggested that a loss of carbon monoxide excretion due to the generation of shunt blood with lung collapse at the alveolar level and a decrease in the total amount of carbon monoxide generated within the lungs resulted in the decrease of a-vCOHb values in group S. Receiver operating characteristic curve analysis of a-vCOHb for predicting the need for respiratory support identified an a-vCOHb cut-off value of 0.3% with a sensitivity of 75% and specificity of 74% (p < 0.001).

An a-vCOHb cut-off value of 0.3% may be useful in determining the severity of lung disease in the early neonatal period.