Bicarbonate-based haemofiltration in the management of acute renal failure with lactic acidosis

Continuous haemofiltration with lactate-based replacement fluid is widely used for the treatment of acute renal failure (ARF). In the presence of lactic acidosis, such treatment exacerbates rather than improves the clinical state. Continuous haemofiltration using a locally-prepared bicarbonate-based replacement fluid was performed in 200 patients over 7 years. All the patients had ARF with concomitant lactic acidosis, or demonstrated lactate intolerance after starting haemofiltration with lactate-based replacement fluids. In every case it was possible to correct the acidosis without inducing either extracellular volume expansion or hypernatraemia. In 89 patients (45%), the lactic acidosis resolved while being treated with bicarbonate-based haemofiltration. Fifty-seven patients (28.5%) survived. Significant differences at presentation in the group who survived, compared with those who died, were seen in age (50.8 vs. 57.1), mean arterial pressure (68.5 vs. 60.0 mmHg) and APACHE II score (32.1 vs. 38.9). Neither the severity of the presenting acidosis nor the arterial blood lactate appeared to predict outcome. Patients who developed ARF and lactic acidosis after cardiac surgery had a low survival rate. The combination of ARF and lactic acidosis that cannot safely be treated by haemofiltration using lactate-based replacement fluids can be managed with bicarbonate-based haemofiltration.