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

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 HCO3- 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, 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. 8.57 +/- 5.71 mmol/l and venous HCO3-, 10.46 +/- 5.73 mmol/l. The respective mean differences between arterial and venous pH and arterial and venous HCO, 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, 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 HCO3- were 0.05 +/- 0.01 and -1.66 +/- 0.58 mmol/l. Although in healthy controls the correlation between arterial and venous pH values (r(2): 0.595) and arterial and venous HCO3- values (r(2): 0.552) were moderate, these correlations were significantly increased in both the acidotic patient group (r(2): 0.979 and 0.990) and the DKA group (r(2): 0.989 and 0.995) Conclusion A venous blood sample can be used to evaluate the acid-base status in uremic and DKA patients. Copyright (C) 2000 S. Karger AG, Basel.