Comparison of arterial and venous blood gases in patients with COPD (Chronic Obstructive Pulmonary Disease) and CLD (Chronic Liver Disease).

Objective: To Determine Correlation between mean Venous and Arterial Blood Gases in patients with COPD and CLD. Study Design: Cross Sectional Descriptive study. Setting: Department of Internal Medicine (MW6) and Accident and Emergency Department of PIMS, Islamabad. Period: 3rd September 2021 to 3rd March 2022. Methods: The study included 110 patients with COPD and CLD who were hospitalized to MW6 and the Emergency Department. The correlation sample size calculator was used to determine the sample size. Consecutive Non-Probability Sampling was the method used to choose samples. Patients with COPD and CLD who were older than thirty years, regardless of gender, were included in the study; however, patients with other metabolic disorders, such as diabetic ketoacidosis, lactic acidosis, a history of poisoning, etc., were not. Results: The average age of patients was 66.3 + 13.6 years and male were 79 (71.8%). Samples were taken from arteries and veins of each patient and pH was calculated. The average pH1 (arterial) level was found to be 7.41 + 0.68 mg/dl whereas the average pH2 (venous) level was 7.35 + 0.76 mg/dl in current study. Conclusion: Venous blood gas analysis cannot be used in place of arterial blood gas analysis due to the differences in pH levels. In many clinical circumstances, venous pH, PCO2, and bicarbonate cannot replace their arterial equivalents.