REMOVAL OF PIPERACILLIN IN CRITICALLY ILL PATIENTS UNDERGOING CONTINUOUS VENOVENOUS HEMOFILTRATION

Objective: Continuous hemofiltration is now widely used in the intensi ve care unit, Our study aimed to assess the removal of piperacillin un der continuous hemofiltration and to define a suitable dosage regimen of administration. Design: Prospective study of blood and ultrafiltrat e concentrations of piperacillin to assess the pharmacokinetics of the antibiotic. Setting: The medical intensive care unit of a teaching ho spital. Patients: Ten patients were included in the study, Six patient s were receiving their first dose of piperacillin (group 1) and four h ad already been treated for 2 to 6 days (group 2), The mean Simplified Acute Physiology II score was 74 +/- 6 (SEM), and the number of organ failures was 3.6 +/- 0.3 (range 3 to 5), Renal failure was related to septic shock in seven patients and to cardiogenic shock in three pati ents, Seven patients were anuric, Hepatic dysfunction was present in f our of the ten patients, Interventions: Patients were treated with con tinuous venovenous hemofiltration using a hollow polysulfone capillary fiber, Piperacillin (4 g) was injected intravenously over 20 mins, Ar terial blood and ultrafiltrate were sampled immediately before the inj ection and then every hour until 8 hrs after injection time, Piperacil lin concentrations were assayed using high performance liquid chromato graphy. Measurements and Main Results: In group 1, the mean serum peak concentration of piperacillin was in the normal range (125 +/- 21 mg/ L), but trough values were higher (48 +/- 8 mg/L) than in normal subje cts, In group 2, trough values before the injection were increased in all patients (188 +/- 71 mg/L), At T1, blood peak concentration reache d 470 +/- 127 mg/L, A small amount of piperacillin was retrieved from the ultrafiltrate, The elimination half-life was 5.1 +/- 1.4 and 4.8 /- 1.4 hrs in groups 1 and 2, respectively, Conclusions: Piperacillin was not removed to a significant extent during continuous hemofiltrati on. Further, in the intensive care unit, patients in shock with multip le organ failure such as liver failure might behave differently from p atients with stable end stage renal disease, A 4-g dose of piperacilli n twice a day is recommended in such patients.