Comparison of Blood Gas and Acid-Base Measurements in Arterial and Venous Blood Samples in Patients with Uremic Acidosis and Diabetic Ketoacidosis in the Emergency Room

Abstract

Background/aims: The aim of this study was to examine a plausible correlation between venous and arterial blood gas values in acidotic patients with chronic uremia or diabetic ketoacidosis (DKA). Methods: A total of 152 arterial and 152 venous blood samples from uremic patients (n = 100), DKA patients (n = 21) and healthy controls (n = 31) were analyzed for measurements of blood gas and acid-base status. Results: The means of arterial and venous pH, and arterial and venous HCO^–₃ values for the uremic patients were 7.17 ± 0.14, 7.13 ± 0.14, 10.13 ± 4.26 and 11.86 ± 4.23 mmol/l, respectively. The respective mean differences between arterial and venous pH values and arterial and venous HCO^–₃ values were 0.04 ± 0.02 and –1.72 ± 0.42 mmol/l, respectively, for these patients. The means of the laboratory findings of DKA patients were arterial pH, 7.15 ± 0.15; venous pH, 7.10 ± 0.15; arterial HCO^–₃, 8.57 ± 5.71 mmol/l and venous HCO^–₃, 10.46 ± 5.73 mmol/l. The respective mean differences between arterial and venous pH and arterial and venous HCO^–₃ for this group were calculated to be 0.05 ± 0.01 and –1.88 ± 0.41 mmol/l. In the healthy controls, the means of arterial and venous pH, and arterial and venous HCO^–₃ values were 7.39 ± 0.02, 7.34 ± 0.02, 24.91 ± 0.82 and 26.57 ± 0.83 mmol/l, respectively. For the healthy controls the mean differences between the respective values in arterial and venous pH, and arterial and venous HCO^–₃ were 0.05 ± 0.01 and –1.66 ± 0.58 mmol/l. Although in healthy controls the correlation between arterial and venous pH values (r²: 0.595) and arterial and venous HCO^–₃ values (r²: 0.552) were moderate, these correlations were significantly increased in both the acidotic patient group (r²: 0.979 and 0.990) and the DKA group (r²: 0.989 and 0.995) Conclusion: A venous blood sample can be used to evaluate the acid-base status in uremic and DKA patients.