Comparison of arterial and venous blood gas values in the initial emergency department evaluation of patients with diabetic ketoacidosis

Study objective: To determine whether venous blood gas values can replace arterial gas Values in the initial emergency department evaluation of patients with suspected diabetic ketoacidosis. Methods: This prospective comparison was performed in an adult university teaching hospital ED. Samples for arterial and venous blood gas analysis were obtained during initial ED evaluations. The venous gas samples were collected with samples for other blood tests at the time of intravenous line insertion. Both arterial and venous samples were obtained before the initiation of treatment. Result: Data from 44 episodes of diabetic ketoacidosis in 38 patients were analyzed. Laboratory findings of those patients with diabetic ketoacidosis were as follows (mean+/-SD): arterial pH, 7.20+/-.14; venous pH, 7.17+/-.13; serum glucose, 33.8+/-16 mmol/L (609+/-288 mg/dL); arterial HCO3-, 11.0+/-6.0 mmol; venous HCO3-, 12.8+/-5.5 mmol/L; serum CO2, 11.8+/-5.0 mmol/L; and anion gap, 26.7+/-7.6 mmol/L. The mean difference between arterial and venous pH values was 0.03 (range 0.0 to 0.11). Arterial and venous pH results (r=.9689) and arterial and venous HCO3- results (r=.9543) were highly correlated and showed a high measure of agreement. Conclusion: Venous blood gas measurements accurately demonstrate the degree of acidosis of adult ED patients presenting with diabetic ketoacidosis.