Published: 2020-05-22

Endtidal carbonmonoxide and carboxyhemoglobin for prediction of significant hyperbilirubinemia in healthy Indian neonates >35 weeks of gestation

Gokul Krishnan R., Mangalabharathi S., Mohammed Sajjid, Ramya S.


Background: Endtidalcarbonmonoxide (ETCOc) and Carboxyhemoglobin (COHB) levels correlate well to bilirubin production and an availability of non-invasive point of care (POC) device in predicting significant hyperbilirubinemia is of great advantage when compared to measurement of serum bilirubin. Objective of the study is to measure a value of ETCOc and COHB in the early neonatal period for the prediction of significant hyperbilirubinemia.

Methods: This was the descriptive Cross Sectional Study. ETCOc and COHB were measured 12th hourly for 72 hours followed by TSB in whom the TCB was >14mg/dl. Neonates were classified as jaundiced whose TSB values were in phototherapy range as per AAP Recommendations. Receiver Operative Curves (ROC) were created by appropriate statistical software for ETCOc and COHb to predict significant hyperbilirubinemia. The Sensitivity, Specificity, Positive predictive value, Negative predictive value and likelihood ratios of each was determined and the correlation between ETCOc and COHb levels, ETCOc and TCB, COHB and TCB at different hours of age was evaluated.

Results: Among the total 320 infants, 156 of them developed significant hyperbilirubinemia. The ETCOc and COHB level at 60 hours of age was the most predictive of significant hyperbilirubinemia by ROC analysis. ETCOc cut-off of 1.65 ppm at 60 hours of age has a sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio of 84.6%, 80.5%, 80.5% and 84.6%, 4.33 and 0.19. COHB cut-off of 1.32 ppm at 60 hours of age has a sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio of 84.6%, 81%, 80% and 84.2%, 4.34 and 0.19.ETCOc had a maximum correlation with COHB at 48 hours of age.

Conclusions: An increased level of Endtidalcarbonmonoxide and Carboxyhemoglobin in the early neonatal period is useful as a screening test for prediction of significant hyperbilirubinemia.


Carboxyhemoglobin, Early neonatal period, Endtidalcarbonmonoxide corrected, Hyperbilirubinemia

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