Incidence and outcome of metabolic disarrangements consistent with citrate accumulation in critically ill patients undergoing continuous venovenous hemodialysis with regional citrate anticoagulation

BackgroundSystemic citrate accumulation is a complication of regional citrate anticoagulation (RCA) during continuous renal replacement therapy (CRRT). Our objective was to determine the incidence of clinical signs consistent with citrate accumulation in a large and representative cohort of intensive care unit patients undergoing RCA-CRRT.MethodsPatients treated with RCA-CRRT during 2008-2010 were retrospectively analyzed. Decreased systemic ionized calcium (iCa), increased demand for calcium substitution, elevated total calcium to iCa ratio, and metabolic acidosis were evaluated as indicators for citrate accumulation.ResultsIn the 3-year period, 1070 patients were treated with RCA-continuous venovenous hemodialysis. Metabolic signs of citrate accumulation occurred in 32 patients (2.99%, 64.5±14.0 years, 65.6% male, Acute Physiology and Chronic Health Evaluation score 34.2±9.7): systemic iCa decreased to 1.01±0.10 mmol/L with a simultaneous increase of the calcium substitution rate to 129%±26%, and the mean total calcium to iCa ratio increased to 2.51±0.54. All 32 patients had therapy-resistant shock with severe lactic acidosis (pH 7.20±0.11, lactate 136±61 mg/dL), indicating severe intracellular hypoxia. None of the patients survived.ConclusionsThe incidence of disarrangements consistent with citrate accumulation in patients undergoing RCA-continuous venovenous hemodialysis was low, taking place exclusively in patients with severe lactic acidosis due to multiorgan failure. This suggests that the appearance of citrate accumulation is secondary to a severe failure of cellular respiration.