A comparison of arterial and venous blood gas analysis and its interpretation in emergency department: A cross-sectional study

Aim: To determine the agreement between Arterial Blood Gas (ABG) and Venous Blood Gas (VBG) in a pathologically diverse patient population presenting to the emergency department.
Materials and Methods: This cross-sectional study was conducted in the emergency department of a tertiary care hospital during February 2019 - June 2020. A total of 113 Patients presenting with various medical conditions deemed ABG by the physician were recruited. Both arterial and venous blood samples were collected for blood gas analysis. Using a Bland Altman plot, the data obtained were analysed for agreement. IBM SPSS version 22 was used for data analysis.
Results: Among the 113 study participants, the arterial and venous pH values, BE and bicarbonate show acceptably narrow 95% limits of agreement using the Bland–Altman method (-0.06 to 0.08, -4.08 to 2.30 and -2.59 to 0.89, respectively). Agreement in PO2 and SPO2 measurements was poor (95% limits of agreement -8.38 to 101.06 and 0.35 to 0.58 respectively). Agreement of PCO2 shows an acceptably narrow agreement (95% limits of agreement -10.61 to -2.18).
Conclusion: Venous blood gas analysis for pH, bicarbonate and Base Excess may be a reliable substitute for ABG analysis in the initial evaluation of an adult patient presenting to the Emergency Department.