End tidal carbon dioxide monitoring—Its reliability in neonates

Abstract

End tidal Carbon dioxide monitoring was undertaken prospectively in all Ventilated neonates in our NICU admitted from March 1995 to August 1995 irrespective of the birth weight, gestational age and indication of ventilation. The aim was to determine the correlation between ETCO2 and PaCO2 in various clinical situations. The arterial blood gases were obtained in all ventilated babies with simultaneous and continuous ETCO2 monitoring and were analysed by AVL 995 Hb blood gas analyser. ETCO2 was analysed by side stream technique by Datex Cardiocap II monitor. A total of 152 samples from in-dwelling radial artery catheters were analysed from babies with birth weight from 900 g to 3400 g, gestation age from 28 to 42 wks and were ventilated for various indications like Severe Birth Asphyxia (SBA), Meconium Aspiration Syndrome (MAS), Recurrent Apnoea and Hyaline Membrane Disease (HMD). Statistical analysis was done in 10 groups to see if the ETCO2 correlated with its corresponding PaCO2 value. The study groups comprised three groups based on birth weight being < 1.5-2.5 kg and > 2.5 kg three groups as per the gestational age being 28-31+6 wks, 32-36+6 wks and 37-41+6 wks and four groups as per the need for ventilation being Severe Birth Asphyxia, Meconium Aspiration Syndrome, Apnoea of Prematurity and Hyaline Membrane Disease. Results of the correlation analysis revealed that the correlation coefficient in the study group ranged from 0.55 to 0.96 and was statistically significant in babies > 2.5 kg and 1.5-2.5 kg, in term and preterms 32-36 wks, and in babies with MAS, SBA and Recurrent Apnoea. The correlation coefficient was lowest in babies with HMD, being 0.55. The study showed that ETCO2 correlates closely with PaCO2 in most clinical situations in neonates and we recommend its use in all level III NICUs in ventilated babies.

Agreement of Carbon Dioxide Levels Measured by Arterial, Transcutaneous and End Tidal Methods in Preterm Infants ≤28 Weeks Gestation

“…An intraclass correlation coefficient (ICC) of 0.60 for CO 2 assessment by PetCO 2 or TcPCO 2 compared to PaCO 2 measurement for preterm infants has been reported in a previous study. 5 A total of 27 preterm infants were required to demonstrate an agreement level of 0.80 at a 5% type I error and 20% type II error at any time of sampling. 13 Bland Altmann analysis was used to determine precision and bias.…”

“…Noninvasive monitoring of carbon dioxide such as transcutaneous partial pressure of carbon dioxide (TcPCO2) and partial pressure of end-tidal carbon dioxide in the expired air (PetCO 2 ) have shown usefulness in adults, children and full-term neonates. [1][2][3][4][5][6][7][8][9] These methods offer the advantages such as simplicity, reduction in blood sampling and incidence of iatrogenic anemia and cost effectiveness.…”

Measuring Physiological Changes during the Transition to Life after Birth

“…Although the number of out-of-range Pa CO 2 values was not reduced, ET CO 2 was lower during ventilation than during breathing [95]. While studies in the neonatal intensive care unit have found that ET CO 2 closely correlates with Pa CO 2 [96,97,98], it is important not to extrapolate these findings to the situation in the delivery room, when the lung is partially liquid filled. The assumption that ET CO 2 will approximate Pa CO 2 levels relies on the fact that CO 2 exchange in the lung is not diffusion limited.…”

“…Gas exchange measurements during transition, using capnography, could assist in defining adequate tidal volumes [96,97,98] and the total amount of proper gas exchange. However, this technique can be influenced by other variables such as mask leak and the dead space of the mask and sensor.…”

Minimizing blood loss and the need for transfusions in very premature infants

“…Four (n=723) assessed end-tidal CO 2 , one assessed transcutaneous CO 2 (n=46) and one assessed both (n=37). (41)(42)(43)(44)(45)(46) The correlation between blood CO 2 and noninvasive monitoring was acceptable (correlation coefficient 0.55 to 0.82). In infants with significant pulmonary disease, the end-tidal CO 2 partial pressure of CO 2 may be quite discrepant due to large dead space volumes.…”