VBG Vs ABG in DKA Patients

BACKGROUND: Diabetic ketoacidosis (DKA) is a life-threatening endocrine emergency, traditionally requiring arterial blood gas (ABG) analysis for diagnosis and monitoring. The aim of our study was to assess the comparability of arterial and venous blood samples for pH and bicarbonate measurements in patients with DKA. MATERIALS AND METHODS: Prospective, observational study of patients with suspected DKA coming to ED (Emergency department) was carried out. Inclusion criteria were capillary blood glucose equal to or greater than 250 mg/dL, ketonuria, and clinical signs and symptoms of DKA. Patients with coexisting respiratory or renal diseases and hemodynamic instability were excluded from the study. ABG and VBG (Venous blood gas) samples were taken simultaneously (within 2 minutes) before treatment. Pearson’s correlation coefficient and Bland-Altman bias plot were used to compare pH and bicarbonate values of arterial and venous blood samples. RESULTS: Data from 50 episodes of diabetic ketoacidosis in 50 patients were analyzed. Laboratory findings of those patients with diabetic ketoacidosis were as follows (mean±SD): arterial pH, 7.131±0.139; venous pH, 7.108±0.147; serum glucose, 442±113 mg/dL; arterial HCO3–, 6.104±3.133 mmol/L and venous HCO3–, 6.234±3.358 mmol/L. The mean difference between arterial and venous pH values was 0.022 (range 0.0 to 0.054). Arterial and venous pH results (r=0.9959) and arterial and venous HCO3– results (r=0.9025) were highly correlated and showed a high degree of agreement. CONCLUSION: A venous blood sample is sufficiently reliable to assess pH and bicarbonate in patients with DKA suggesting that venous sampling alone is appropriate in the management of DKA.