Patient characteristics, vital signs and tcpCO2 dynamics significantly influence tcpCO2 accuracy in extremely preterm infants: an observational study.

PURPOSE: The estimation of the partial pressure of carbon dioxide (pCO2) is of interest in extremely premature infants. Neonatal intensive care units use transcutaneous pCO2 monitoring (tcpCO2) as a trend parameter and continuous estimate of pCO2. Our objective was to identify candidate influence factors on the accuracy of tcpCO2 in extremely premature infants in their first week of life.

METHODS

In a retrospective cohort study, linear mixed-effects models were used to analyze the influence of patient characteristics, vital signs and tcpCO2 dynamics on the difference of tcpCO2 and capillary pCO2 as reference (ΔpCO2). Candidate parameters identified in univariate analyses were incorporated into multivariable models to confirm their effect on ΔpCO2.

RESULTS

500 measurements from 29 extremely preterm infants were analyzed. Postnatal age, mean fraction of inspired oxygen, tcpCO2, capillary pCO2, last tcpCO2 and last ΔpCO2 were positively associated with ΔpCO2, while gestational age and hemoglobin were negatively associated with ΔpCO2.

CONCLUSION

These candidate parameters may be used to enhance the non-invasive estimation of pCO2 from tcpCO2 in the future.

TRIAL REGISTRATION: German Clinical Trials Register (DRKS00033228, first registered 29 August 2024, https://drks.de/search/en/trial/DRKS00033228/details).