Pharmacokinetics of vancomycin during continuous hemodiafiltration.

Abstract

To study the pharmacokinetics of vancomycin in three patients with acute renal failure related to multi-organ failure during continuous venovenous hemodiafiltration (CVVHD). Prospective exploratory, open-labelled study. Critical Care Unit in a University Medical Centre. 3 patients exhibiting hemodynamic instability and oligo-anuric acute renal failure requiring extra-renal epuration were included in this study. Every patient received 7.5 mg/kg IV vancomycin over 1 h for a documented or suspected nosocomial staphylococcal infection. Serum and dialysate outlets samples were collected before infusion and 1, 3, 6, 12, 18, 24 after the end of infusion. Mean age was 58.7 years (range 41-79) and mean SAPS 15.7 (9-23). The mean peak concentrations were 27.3 mg/l (range 15.6-45.6) one hour after the end of infusion. The average remaining vancomycin concentration 24 h after the onset of infusion was 3.6 mg/l (range 2.6-4.5). The mean terminal disposition rate constant and elimination half-life were 0.05 h-1 and 13.9 h respectively. Mean total body clearance was 38.9 +/- 4.3 ml/min and dialysate outlet (DO) clearance 4.2 +/- 1.3 ml/min. The mean volume of distribution was 47.4 +/- 6.4 l. CVVHD is effective for vancomycin elimination. In these patients, the elimination half-life is almost constant, involving a following injection of vancomycin 12 h later to achieve effective concentrations.