Correlation of PaCO2 and ETCO2 in COPD Patients with Exacerbation on Mechanical Ventilation

Diksha Tyagi, Manjunath B Govindagoudar, Sushmitha Jakka, Sateesh Chandra, Dhruva Chaudhry, Diksha Tyagi, Manjunath B Govindagoudar, Sushmitha Jakka, Sateesh Chandra, Dhruva Chaudhry

Abstract

Introduction: Chronic obstructive pulmonary disease (COPD) patients in hypercapnic respiratory failure require multiple arterial blood gas (ABG) analysis for monitoring. It is a painful, invasive, and expensive investigation. This study was aimed at finding an agreement between end-tidal carbon dioxide (ETCO2, a noninvasive modality) and arterial carbon dioxide (PaCO2) in COPD patients with acute exacerbation on mechanical ventilation. Materials and methods: A prospective observational study was conducted in COPD patients who required mechanical ventilation. ETCO2 was recorded by mainstream capnography along with ABG analysis. An agreement between PaCO2 and ETCO2 was assessed. The effect of various factors on correlation was also studied. Results: A total of 100 patients with COPD in hypercapnic respiratory failure were included. Seventy-three percentage of patients were managed on invasive mechanical ventilation (IMV). The mean ETCO2 and PaCO2 were 48.66 ± 15.57 mm Hg and 75.52 ± 21.9 mm Hg, respectively. There was a significant correlation between PaCO2 and ETCO2 values (r = 0.82, 95% confidence interval of r = 0.78-0.86, p <0.0001). The Bland-Altman analysis shows the mean bias as -19.4 (95% limits of agreement = -40.0-1.1). Pearson's correlation coefficient was 0.84 in intubated patients and 0.58 in patients on noninvasive ventilation (NIV). Pearson's correlation coefficient between PaCO2 and ETCO2 in subjects with consolidation, cardiomegaly, hypotension, and raised pulmonary artery pressures was 0.78, 0.86, 0.85, and 0.86, respectively. Conclusion: Mainstream ETCO2 measurement accurately predicts the PaCO2 in COPD patients on IMV. However, for patients on NIV, ETCO2 is insufficient in monitoring PaCO2 levels due to weak correlation. Clinical significance: ETCO2 can be used as a noninvasive modality in intensive care unit for monitoring the PaCO2 in COPD patients on IMV. This can reduce the requirement of arterial blood sampling to a minimum number, in turn, reducing the cost of the treatment and discomfort to the patients. How to cite this article: Tyagi D, Govindagoudar MB, Jakka S, Chandra S, Chaudhry D. Correlation of PaCO2 and ETCO2 in COPD Patients with Exacerbation on Mechanical Ventilation. Indian J Crit Care Med 2021;25(3):305-309.

Keywords: Arterial carbon dioxide; Chronic obstructive pulmonary disease; End-tidal carbon dioxide; Mechanical ventilation.

Conflict of interest statement

Source of support: Nil Conflict of interest: None

Copyright © 2021; Jaypee Brothers Medical Publishers (P) Ltd.

Figures

Fig. 1
Fig. 1
Scatter plot showing a strong correlation between arterial and end-tidal carbon dioxide (r = 0.82)
Fig. 2
Fig. 2
Bland.Altman plot for arterial and end-tidal carbon dioxide showing good agreement (mean bias = −19.4, 95% limits of agreement = −40.0−1.1)
Figs 3A and B
Figs 3A and B
Effect of type of mechanical ventilation (invasive vs noninvasive) on correlation of arterial and end-tidal carbon dioxide

References

    1. Global Strategy for the Diagnosis, Management and Prevention of COPD, Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2017 report. Available at:
    1. Plant PK, Owen J, Elliott MW. One year period prevalence study of respiratory acidosis in acute exacerbation of COPD; implications for the provision of non-invasive ventilation and oxygen administration. Thorax. 2000;;55((7):):550––554.. doi: 10.1136/thorax.55.7.550. DOI:
    1. Roberts CM, Stone RA, Buckingham RJ, Pursey NA, Lowe D. Acidosis, non-invasive ventilation and mortality in hospitalised COPD exacerbations. Thorax. 2011;;66((1):):43––48.. doi: 10.1136/thx.2010.153114. DOI:
    1. Garcia E, Abramo TJ, Okada P, Guzman DD, Reisch JS, Wiebe RA. Capnometry for noninvasive continuous monitoring of metabolic status in pediatric diabetic ketoacidosis. Crit Care Med. 2003;;31((10):):2539––2543.. doi: 10.1097/01.CCM.0000090008.79790.A7. DOI:
    1. Gilhotra Y, Porter P. Predicting diabetic ketoacidosis in children by measuring end-tidal CO2 via non-invasive nasal capnography. J Paediatr Child Health. 2007;;43((10):):677––680.. doi: 10.1111/j.1440-1754.2007.01186.x. DOI:
    1. Fearon DM, Steele DW. End-tidal carbon dioxide predicts the presence and severity of acidosis in children with diabetes. Acad Emerg Med. 2002;;9((12):):1373––1378.. doi: 10.1111/j.1553-2712.2002.tb01605.x. DOI:
    1. Agus MS, Alexander JL, Mantell PA. Continuous non-invasive end-tidal CO2 monitoring in pediatric in patients with diabetic ketoacidosis. Pediatr Diabetes. 2006;;7((4):):196––200.. doi: 10.1111/j.1399-5448.2006.00186.x. DOI:
    1. Pishbin E, Ahmadi GD, Sharifi MD, Deloei MT, Shamloo AS, Reihani H. The correlation between end-tidal carbon dioxide and arterial blood gas parameters in patients evaluated for metabolic acid-base disorders. Electron Physician. 2015;;7((3):):1095––1101.. doi: 10.14661/2015.1095-1101. DOI:
    1. Bingheng L, Jianxin C, Yu C, Yu Y. Comparison of peripheral venous and arterial blood gas in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD): a meta-analysis. Notfall Rettungsmed. 2019;;22::620––627.. doi: 10.1007/s10049-018-0469-9. DOI:
    1. Razi E, Moosavi GA, Omidi K, Saebi AK, Razi A. Correlation of end tidal CO2 and arterial CO2 in mechanically ventilated patients. Arch Trauma Res. 2012;;1((2):):58––62.. doi: 10.5812/atr.6444. DOI:
    1. Yosefy C, Hay E, Nasri Y, Magen E, Reisin L. End tidal carbon dioxide as a predictor of the arterial PCO2 in the emergency department setting. Emerg Med J. 2004;;21((5):):557––559.. doi: 10.1136/emj.2003.005819. DOI:
    1. Corbo J, Bijur P, Lahn M, Gallagher EJ. Concordance between capnography and arterial blood gas measurements of carbon dioxide in acute asthma. Ann Emerg Med. 2005;;46((4):):323––327.. doi: 10.1016/j.annemergmed.2004.12.005. DOI:
    1. Moses JM, Alexander JL, Agus MS. The correlation and level of agreement between end-tidal and blood gas pCO2 in children with respiratory distress: a retrospective analysis. BMC Pediatr. 2009;;9::20.. doi: 10.1186/1471-2431-9-20. DOI:
    1. Kartal M, Goksu E, Eray O, Isik S, Sayrac AV, Yigit OE et al. The value of ETCO2 measurement for COPD patients in the emergency department. Eur J Emerg Med. 2011;;18((1):):9––12.. doi: 10.1097/mej.0b013e328337b9b9. DOI:
    1. Pekdemir M, Cinar O, Yilmaz S, Yaka E, Yuksel M. Disparity between mainstream and sidestream end-tidal carbon dioxide values and arterial carbon dioxide levels. Respir Care. 2013;;58((7):):1152––1156.. doi: 10.4187/respcare.02227. DOI:

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