title: Neonatal bilirubin production estimated from "end-tidal" carbon monoxide concentration.
abstract: The relationship between the pulmonary excretion rate of carbon monoxide (VECO) and the concentration of CO, in a sample of breath, drawn through a nasopharyngeal catheter at end-expiration, was assessed in 25 studies of nine preterm and 14 term infants. The VECO and this approximate end-tidal sample of CO (ETCO) correlated significantly over a wide range of CO elimination rates: VECO = 10.45 ETCO + 2.25 (n = 25, r = 0.95). The ETCO correctly predicted elevations in VECO greater than 2 SD of the mean VECO for normal infants (13.9 +/- 3.5 microliter/kg/h), with 90% sensitivity and 73% specificity (p less than 0.01). Three subjects with Rh isoimmune hemolytic disease were easily identified by the ETCO as well as the VECO. The ETCO is a simple, noninvasive measurement for rapidly identifying infants with significant hemolytic disease.
mesh_terms: D001663:Bilirubin / Q000096:biosynthesis*; D001944:Breath Tests; D002248:Carbon Monoxide / Q000032:analysis*; D002263:Carboxyhemoglobin / Q000032:analysis; D004899:Erythroblastosis, Fetal / Q000175:diagnosis; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D011247:Pregnancy
chemical_list: D002248:Carbon Monoxide; D002263:Carboxyhemoglobin; D001663:Bilirubin