Can Venous Blood Gases Replace Arterial Blood Gases in Diabetic Ketoacidosis/Renal Failure Induced Metabolic Acidosis?

Abstract

The study aims to identify the correlation between arterial and venous blood gas variables, in patients with metabolic acidosis secondary to renal failure and/or diabetic ketoacidosis(DKA). Paired arterial and venous blood samples of 100 patients, with metabolic acidosis resultant to renal failure and/or diabetic ketoacidosis during 2009-2011, were analyzed and the correlation between the variables were assessed using SPSS software, applying Pearson's product moment correlation coefficient, Linear regression, Statistical parameter R 2 and Chi-square test. Results: Mean ABG values for pH, HCO3, pCO2 and lactate were (7.29 +/- 0.448, 12.12 +/- 2.61, 25.2 +/- 4.0 and 5.39 +/-1.95 respectively) and mean VBG values for the same were (7.292 +/- 0.0451, 12,23 +/- 2.55, 27.8 +/- 3.9, and 5.19 +/- 1.81). Pearson product moment coefficient for pH, HCO3, pCO2 and lactate were 0.919, 0.967, 0.966 and 0.924 , with p <0.001 . Percentage variation in ABG as explained by VBG for pH = 84.4%, HCO3 =93.6%, pCO2 = 93.2% and lactate = 85.4%. Regression equations to predict arterial from venous values:-Arterial pH = 0.631 +0.913 x venous pH (R 2 =0.844), Arterial HCO3 = 0.990 x venous HCO3 (R 2 =0.936), Arterial pCO2 = -2.546 + 0.997 x venous pCO2 (R 2 =0.932), Arterial lactate = 0.993 x venous lactate (R 2 =0.854). Arterial and venous blood gas values showed significant correlation coefficient for pH, HCO3, pCO2 and lactate. Hence, VBG may be used as an alternative to ABG in the initial management metabolic acidosis secondary to diabetic ketoacidosis and/or renal failure.