Capnography in Pediatric Critical Care Unit and Correlation of End-Tidal and Arterial Carbon Dioxide in Ventilated ChildrenFunding None.
Recording of end-tidal carbon dioxide (EtCO2) noninvasively reflects a real-time estimation of arterial carbon dioxide (PaCO2 [partial pressure of CO2]). However, as the EtCO2 is dependent on metabolism, perfusion, and ventilation, predicting PaCO2 from EtCO2 is not linear. The objective of the study was to find out the predictability of PaCO2 from EtCO2 in PICU and to evaluate the factors affecting the correlation of EtCO2 and PaCO2 in critically ill ventilated children. The design involved was prospective observational study. The setting discussed over here is that of pediatric intensive care unit (PICU) of tertiary care hospital. A total of 160 children between 1 month and 14 years received mechanical ventilation. EtCO2, PaCO2, PaO2/FiO2 (PF) ratio, oxygenation index (OI), and ventilation index (VI) are the factors involved in main outcome measures. A total of 535 pairs of EtCO2 and PaCO2 were recorded in 160 ventilated children during the stable hemodynamic state. Mean age and weight (Z-score) of patients were 31.15 ± 40.46 months and −2.10 ± 1.58, respectively. EtCO2 and PaCO2 differences were normal (2–5 mm of Hg) in 393 (73.5%) pairs. High gradient (>5 mm of Hg) was mostly found with children with pneumonia, prolonged ventilation, and pressure mode of ventilation (p < 0.05). EtCO2 had a strong positive correlation with PaCO2 (r = 0.723, 95% confidence interval [CI] = 0.68 and 0.76) and not significantly affected by PF ratio or OI. However, presence of pneumonia and high ventilation index (VI > 20) adversely affected the relationship with poor correlation coefficient (r = 0.449, 95% CI = 0.30, 0.58 and r = 0.227, 95% CI = 0.03, 0.41, respectively). EtCO2 reading showed good validity to predict PaCO2 and not affected by oxygenation parameters. The correlation was affected by the presence of pneumonia and high ventilation index; hence it is recommended to monitor PaCO2 invasively in these patients till a good correlation is established.
Keywordscapnography - end-tidal carbon dioxide - PaCO2 - pediatric intensive care unit - arterial blood gas
B.K.M. conceived and designed the study, analyzed the data, revised the article, and act as the guarantor of the study. A.K. and D.D.P. collected the data and drafted the paper. A.K. and S.K.S. analyzed the data and revised the article. All the authors approved the final manuscript.
Received: 07 April 2020
Accepted: 07 June 2020
20 August 2020 (online)
© 2020. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/).
Georg Thieme Verlag KG
Stuttgart · New York
- 1 Riley CM. Continuous capnography in pediatric intensive care. Crit Care Nurs Clin North Am 2017; 29 (02) 251-258
- 2 Selby ST, Abramo T, Hobart-Porter N. An update on end-tidal CO2 monitoring. Pediatr Emerg Care 2018; 34 (12) 888-892
- 3 IRMA Maximo carbon-dioxide gas analyzer manual. Anon, 2017. Available at: http://www.spectrummedical.com/uploads/documents/IRMA-ISA-brochure-web.pdf . Accessed June 1, 2017
- 4 Weil MH. . Defining Hemodynamic Instability. In: Pinsky MR, Payen D, eds. Functional Hemodynamic Monitoring, 1st ed. Germany: Springer; 2005:9–17
- 5 Kwon MA. The effect of a pediatric heat and moisture exchanger on dead space in healthy pediatric anesthesia. Korean J Anesthesiol 2012; 62 (05) 418-422
- 6 Ventilation index. Available at: http://www-users.med.cornell.edu/~spon/picu/calc/ventindx.htm . Accessed June16, 2018
- 7 Instrumentation Laboratory Worldwide. (GEM Premier 3000) manual. Anon;2017 Available at: http://kr.werfen.com/~/media/werfenmedicalil/doc/critical%20care/gem%203000.pdf . Accessed June 1, 2017
- 8 Eschweiler automated gas analyzer manual Anon; 2017. Available at: http://www.frankshospitalworkshop.com/equipment/documents/automated_analyzer/user_manuals/Eschweiler%20Combi%20line%20-%20User%20manual.pdf . Accessed June 1, 2017
- 9 Siobal MS, Ong H, Valdes J, Tang J. Calculation of physiologic dead space: comparison of ventilator volumetric capnography to measurements by metabolic analyzer and volumetric CO2 monitor. Respir Care 2013; 58 (07) 1143-1151
- 10 Yang JT, Erickson SL, Killien EY, Mills B, Lele AV, Vavilala MS. Agreement between arterial carbon dioxide levels with end-tidal carbon dioxide levels and associated factors in children hospitalized with traumatic brain injury. JAMA Netw Open 2019; 2 (08) e199448
- 11 Mehta H, Kashyap R, Trivedi S. Correlation of end tidal and arterial carbon dioxide levels in critically Ill neonates and children. Indian J Crit Care Med 2014; 18 (06) 348-353
- 12 Meredith KS, Monaco FJ. Evaluation of a mainstream capnometer and end-tidal carbon dioxide monitoring in mechanically ventilated infants. Pediatr Pulmonol 1990; 9 (04) 254-259
- 13 McDonald MJ, Montgomery VL, Cerrito PB, Parrish CJ, Boland KA, Sullivan JE. Comparison of end-tidal CO2 and PaCO2 in children receiving mechanical ventilation. Pediatr Crit Care Med 2002; 3 (03) 244-249
- 14 Hopper AO, Nystrom GA, Deming DD, Brown WR, Peabody JL. Infrared end-tidal CO2 measurement does not accurately predict arterial CO2 values or end-tidal to arterial PCO2 gradients in rabbits with lung injury. Pediatr Pulmonol 1994; 17 (03) 189-196
- 15 Kugelman A, Zeiger-Aginsky D, Bader D, Shoris I, Riskin A. A novel method of distal end-tidal CO2 capnography in intubated infants: comparison with arterial CO2 and with proximal mainstream end-tidal CO2 . Pediatrics 2008; 122 (06) e1219-e1224
- 16 Goonasekera CD, Goodwin A, Wang Y, Goodman J, Deep A. Arterial and end-tidal carbon dioxide difference in pediatric intensive care. Indian J Crit Care Med 2014; 18 (11) 711-715
- 17 McSwain SD, Hamel DS, Smith PB. , et al. End-tidal and arterial carbon dioxide measurements correlate across all levels of physiologic dead space. Respir Care 2010; 55 (03) 288-293