Association of end-tidal and venous carbon dioxide in intubated and ventilated children

 The end-tidal CO2 pressure (PetCO2) monitoring which is a non-invasive method than PvCO2 (venous pressure of carbon dioxide), could determinate a graph depicting the carbon dioxide concentration in blood. The aim of this study was to investigate the correlation between PetCO2-PvCO2 in ventilated children.

 All children intubated in the PICU of Children hospital Tabriz, Iran from 2019 to 2020 using the census method were assessed in terms of initial diagnosis, age, sex, PetCO2, and PvCO2 during a prospective cross-sectional study. Associations between variables were calculated for total patients and patients in the subgroups. Descriptive statistics were used to describe the quantitative analysis of data and the Pearson correlation coefficient and Linear Regression Test were used for the evaluation of the relationship between variables and for assessing the predictive values of PvCO2 using SPSS.26. A P value<0.05 was considered statistically significant.

 Out of 61 samples, 42 (68.9%) patients were males with a median age of 48 months. The mean of PetCO2 and PvCO2 were 20.3±8.5 and 43±12.3 mm Hg, respectively. The correlation of PetCO2-PvCO2 was significant in total patients (P value=0.003, r=0.379) and group 1 (P value=0.009, r=0.374). Furthermore, the results presented the predictive values of PvCO2 for PetCO2 while for one unit increase in the PvCO2 variable, PetCO2 could increase 0.372 units (P value=0.005, Slope b=0.24, Beta coefficient=0.372).

 In most intubated children, PetCO2 may estimate the ventilation and change concentrations of CO2. It is necessary that the sample size of future studies will become large due to the weak correlation.