Comparison of End Tidal Carbon Dioxide and Arterial Blood Bicarbonate Levels in Patients With Exacerbation Chronic Obstructive Pulmonary Disease

Abstract

Background: Arterial Blood Gases (ABG) is performed as the gold standard for monitoring oxygenation and assessing the amount of arterial CO2 retention in patients with acute exacerbation of Chronic Obstructive Pulmonary Disease (COPD), which is an invasive procedure and can just do discontinuous monitoring of oxygenation and retention of CO2. Capnography as a noninvasive tool, can show the amount of end tidal CO2 (ETCO2). Objectives: The aim of this study was to compare the values of ETCO2 with arterial bicarbonate levels in patients with exacerbation of COPD. Patients and Methods: This was an analytical cross-sectional study performed in the Department of Emergency Medicine of Tabriz University of Medical Sciences on patients with COPD admitted to the emergency ward of Imam Reza hospital. Levels of ETCO2 with arterial bicarbonate were compared in patients with COPD. Results: Fifty-seven patients were enrolled; 35 patients (62.5 %) were male. The mean of ETCO2 and PaCO2 of patients were 41.49 ± 9.80 and 64.74 ± 9.76, respectively. The mean of PaCO2 was significantly more than the means of ETCO2 in patients with COPD. The association between arterial bicarbonate and ETCO2 was weak and not significant (P = 0.136 and r = 0.04). Conclusions: Capnography can be used to assess the status of patients with respiratory acidosis in a noninvasive way.