Correlation of Partial Pressure of Arterial Carbon Dioxide and End-Tidal Carbon Dioxide in Intubated Premature Infants - Abstract
Background: Capnometry can reduce arterial blood sampling and allow fast and noninvasive assessments using end-tidal of carbon dioxide (EtCO2).
Objectives: The aims of this study were to evaluate the correlation of partial pressure of arterial CO2 (PaCO2)levels and EtCO2, and to verify whether capnometry would be useful for noninvasive monitoring of CO2 levels in intubated premature infants with and without diffuse parenchymal lung diseases (DPLD).
Methods: This study was conducted in premature infants admitted to the Neonatal Intensive Care Unit (NICU) from August 2014 to November 2016. EtCO2 levels were compared with PaCO2 levels, in intubated premature infants with and without DPLD. Both parameters were obtained daily until tracheal extubation. The correlation coefficient and degree of bias between them was determined.
Results: Overall, 221 measurements of EtCO2 and PaCO2 levels were obtained from 51 neonates. Twenty-eight were obtained from neonates without DPLD (12.7%) and 193 from those with DPLD (87.3%). The most frequent cause of DPLD was respiratory distress syndrome (RDS) in 86.5%. There was a positive correlation between PaCO2 and EtCO2 levels (n = 221; r =0.853; p < 0.0001) in the overall cohort. Both groups showed a good correlation between both parameters, without DPLD (mean bias = 0.21, SD, 7.05; 95% CI -13.61 – 14.05), and with DPLD (mean bias = 0.37, SD, 7.66; 95% CI -14.65 – 15.39).
Conclusions: Capnometry is a useful noninvasive technique to monitor intubated premature infants. EtCO2 measurement may be a valid adjunctive parameter when titrating ventilator support.