Implication of Haemodiafiltration Flow Rate on Amikacin Pharmacokinetic Parameters in Critically Ill Patients.

Background: To analyse the effect of haemodiafiltration (CVVHDF) flow rate on amikacin pharmacokinetics and blood concentrations.

Methods: Prospective observational study. Patients receiving CVVHDF and amikacin treatment were included. Pharmacokinetic parameters were calculated using Bayesian analysis. Spearman correlation test was used in order to assess the influence of CVVHDF flux on amikacin minimum concentration (Cmin) and plasma clearance.

Results: Thirty patients undergoing CVVHDF procedures were included. The treatment with amikacin started at an initial mean dose of 12.4 (4.1) mg/kg/day. An association between the flow rate and Cmin value (r = 0.261; p = 0.161) and plasma clearance was found (r = 0.268; p = 0.152). Four patients (13.3%) were not able to achieve peak concentration over MIC value higher than 8. In 4 patients, amikacin had to be discontinued due to a high Cmin value.

Conclusions: Amikacin clearance in patients with CVVHDF is affected by the flow rate used. Therefore, CVVHDF dose should be taken into account when dosing amikacin.