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Published on: August 19, 2020
Age-specific ETCOc measured by non-dispersive infrared spectroscopy predicts neonatal phototherapy
Yixiang Wu1, Chenyu Zhu1, Yuan Zheng1
1Department of Pediatric, the Fourth Affiliated Hospital of School of Medicine, and International School of Medicine, International Institutes of Medicine, Zhejiang University, Yiwu, China.
Background:
End-tidal carbon monoxide corrected for ambient carbon monoxide (ETCOc), a noninvasive marker of bilirubin production, may help identify neonates at risk for significant hyperbilirubinemia. We aimed to construct an age-specific ETCOc percentile distribution and evaluate its value in predicting phototherapy.
Methods:
In this prospective observational study, neonates underwent serial ETCOc measurements at predefined postnatal time points. Age-specific percentile curves were constructed to describe serial postnatal changes in ETCOc. Receiver operating characteristic analysis was used to assess the predictive performance of ETCOc for phototherapy, and logistic regression was performed to evaluate its independent association with phototherapy risk.
Results:
ETCOc showed clear age-specific serial changes during the early neonatal days. The highest AUC values were observed at 24 and 72 h. Although 72-h ETCOc yielded a slightly higher AUC, the difference was not significant by DeLong test. The AUC of 24-h ETCOc for predicting phototherapy was 0.87 (95% CI: 0.79-0.96). A 24-h ETCOc value above the 75th percentile was associated with increased phototherapy risk, and logistic regression further supported its predictive value.
Conclusions:
ETCOc may be a useful early noninvasive marker for predicting phototherapy in neonates. Age-specific, percentile-based interpretation, particularly at 24 h above the 75th percentile, may improve early risk stratification.
Impact:
ETCOc demonstrated dynamic age-specific changes during the early neonatal period, supporting age-related interpretation rather than a single fixed cutoff. Unlike conventional electrochemical CO sensing approaches, this study applied infrared spectroscopy-based ETCOc measurement throughout the analytical process for neonatal monitoring. A 24-h ETCOc value above the 75th percentile identified neonates at increased risk for subsequent phototherapy. ETCOc may provide a simple, noninvasive tool for early risk stratification and monitoring of neonatal hyperbilirubinemia.
