[Continuous veno-venous hemofiltration in acute renal insufficiency and heart failure]

The application of intermittent renal replacement therapies in critically ill patients with both acute renal failure and heart failure is often associated with circulatory instability and refractory hypotension. We have evaluated the efficacy and safety of a continuous technique (continuous veno-venous hemofiltration-CVVH) in 7 patients (1 male, 6 females, mean age 77 +/- 4 years) referred to our intermediate care unit for oliguria, acute renal failure and NYHA functional class IV, CVVH was performed by a peristaltic pump with blood flow at 200 ml/min, controlled ultrafiltration production rate (25 ml/min), minute to minute microprocessor controlled fluid balance system, biocompatible filters, low-dose prostacyclin for the extracorporeal circuit maintenance. Non invasive evaluation of cardiac function was performed by Doppler echocardiography. A total of 673 hours of CVVH were performed, with a mean extracorporeal circuit duration of 96 +/- 26 hours/patient (range 15-134). Daily urea clearance was 32 +/- 21. A mean body weight decrease of 10% was obtained (body weight before-CVVH 64.5 +/- 6 kg vs end-CVVH 58.5 +/- 5 kg, p < 0.01, paired data Student's test) without any hemodynamic worsening; metabolic control was adequate (urea before-CVVH 251 +/- 73 mg% vs end-CVVH 117 +/- 18 mg%, p < 0.01). Hospital survival was 42% (3/7 patients). In patients with acute renal failure and severe heart failure, CVVH allows an easy control of both fluid balance and acid-base equilibrium, along with the maintenance of acceptable hemodynamic stability.