Correlation of end tidal and arterial carbon dioxide levels in critically Ill neonates and children

Abstract

Aim of the Study:End tidal carbon dioxide (EtCO2) monitoring is considered to reflect real-time estimation of partial pressure of carbon dioxide in arterial blood (PaCO2) noninvasively. However, knowledge about its relationship with PaCO2 in critically ill pediatric and neonatal patients is limited. The primary objective was to evaluate predictive capability of end tidal carbon dioxide monitoring and secondary objective was to determine the influence of severity of lung disease on EtCO2 and PaCO2 relationship.Materials and Methods:This was a prospective, nonrandomized, consecutive enrollment study carried out in neonatal and pediatric intensive care units of a tertiary care children hospital. It was conducted in 66 neonates and 35 children receiving mechanical ventilation. Severity of lung disease was estimated by ventilation index and PaO2/FiO2 (P/F) ratio. Simultaneous recording of EtCO2 and PaCO2 levels was done and data were analyzed for correlation and agreement.Results:In neonates, 150 EtCO2 and PaCO2 pairs were recorded. The mean weight ± SD of patients was 2.1 ± 0.63 kg. PaCO2 had a positive correlation with EtCO2 (r = 0.836, 95% CI = 0.78-0.88). P/F ratio <200 adversely affected relationship. In infants and children, 96 pairs were recorded. Mean age ± SD of patients was 4.20 ± 4.92 years and mean weight ± SD was 13.1 ± 9.49 kg. PaCO2 had an excellent correlation with EtCO2 (r = 0.914, 95% CI = 0.87 and 0.94). P/F ratio <200 adversely affected relationship.Conclusion:EtCO2 monitoring displayed a good validity to predict PaCO2. Correlation was affected by low P/F ratio (<200); hence, it is recommended that blood gases be measured in these patients until such time that a good relation can be established between end tidal and arterial CO2 values.

Capnography in Pediatric Critical Care Unit and Correlation of End-Tidal and Arterial Carbon Dioxide in Ventilated Children

“…However, Mehta et al found a good correlation at high VI in contrary to our findings, which might be due to small sample size in their study compared with our study (15 vs. 95 pairs). 11 Meredith and Monaco and McDonald et al also found a strong positive correlation (n ¼ 1,708, r ¼ 0.716), and (n ¼ 132, r ¼ 0.79) and a negative impact of severe lung disease, similar to our study. However, both the studies had drawn an average of 17 and eight pairs per patient, respectively, whereas we drew up to five pairs per patient to maintain better validity of coefficient of correlation.…”

Validity of sidestream endtidal carbon dioxide measurement in critically ill, mechanically ventilated children

“…Two other studies report better accuracy of sidestream measurement in a neonatal population . The use of mainstream capnography has been evaluated in a PICU in earlier research, showing that it is a reliable instrument . Also, in studies concerning adult populations, the results are very divers and influenced by multiple parameters .…”

Effect of corrective or palliative procedures on arterial to end-tidal carbon dioxide pressure difference in pediatric cardiac surgery

“…In patients with normal cardiopulmonary function, there is a good correlation between ETPCO 2 and arterial carbon dioxide pressure (PaCO 2 ); thus, end-tidal capnometry is widely used in clinical practice to estimate PaCO 2 . Today, the end-tidal capnometry has become a basic and standard procedure for respiratory monitoring during anesthesia and recovery,[1415] ICU,[161718] and at emergency departments (ED). [1920] Takano et al studied the utility of the portable capnometer in general wards or in-home care practice in spontaneously breathing patients and reported that expiratory capnometry gives a reliable estimate of PaCO 2 and can be useful to evaluate the respiratory condition of spontaneously breathing patients.…”

“…They recommended that blood gases should be measured in these patients until the lung disease is healed. [17]…”