Accuracy of noninvasive transcutaneous carbon dioxide monitoring in preterm neonates and very low birth weight infants compared with larger neonates

Purpose Carbon dioxide monitoring is particularly critical in very preterm and very low birth weight (VLBW) infants during the first weeks of life because of the hypercarbia and hypocarbia related morbidities. Conventional methods for measuring partial pressure of carbon dioxide in arterial blood (PaCO 2 ) are challenging for preterm neonates due to complications. Continuous transcutaneous partial pressure of carbon dioxide (TcPCO 2 ) measurement is a well-established method in neonatal intensive care unit. This study primarily aimed to evaluate the accuracy and reliability of transcutaneous partial pressure of CO 2 (TcPCO 2 ) compared with PaCO 2 in preterm neonates and VLBW infants (birth weight <1,500 g), and secondarily to explore how accuracy varies across different gestational age and birth weight strata. Methods This retrospective single-center observational study included a heterogeneous neonatal intensive care unit (NICU) cohort. In neonates admitted to the NICU for respiratory distress, PaCO 2 and TcPCO 2 were measured simultaneously. Statistical analysis included linear regression, calculation of intraclass correlation coefficients (ICC), repeated measures correlation (rmcorr), and the repeated-measures Bland-Altman analysis. Results A total of 143 infants (mean gestational age: 35 ± 3.2 weeks; mean birth weight: 2,374 ± 694.4 g) were recruited, and 410 PaCO 2 and TcPCO 2 measurement pairs were obtained for analysis. A strong correlation (rmcorr = 0.800) with an intraclass correlation coefficient (ICC) of 0.93 (95% CI: 0.91–0.94, p < 0.001) was found in preterm neonates, particularly those with gestational age below 32 weeks, or a birth weight below 1,500 g. Similar correlations were observed in larger infants. Conclusions TcPCO 2 is a noninvasive and reliable method for continuous respiratory monitoring in preterm neonates and very low birth weight infants during the early postnatal period. TcPCO 2 is useful for continuous trend monitoring and may reduce the need for arterial sampling; however, confirmatory blood gas testing is recommended for extreme values or unstable clinical conditions.