Relationship between amikacin pharmacokinetics and biological parameters associated with organ dysfunction: a case series study of critically ill patients with intra-abdominal sepsis.

OBJECTIVES This study aimed to evaluate the relationship between amikacin pharmacokinetics and the biomarkers associated with organ dysfunction in critically ill patients with intra-abdominal sepsis. METHODS A case series involving critically ill patients with intra-abdominal sepsis who received an amikacin loading dose of 20-25 mg/kg intravenous infusion was studied. The 1-, 2-, 4-, 6- and 24-hour amikacin serum concentrations were measured to calculate the pharmacokinetic parameters. The Sequential Organ Failure Assessment (SOFA) score, white blood cells, neutrophil to lymphocyte ratio, platelet count, serum creatinine, creatinine clearance, bilirubin, partial pressure of oxygen to fraction of inspired oxygen ratio, serum albumin, procalcitonin, lactate level, erythrocyte sedimentation rate (ESR) and C-reactive protein were recorded. A linear regression analysis was performed to examine the relationship between the amikacin pharmacokinetics and the biological parameters. RESULTS Twenty-one patients were studied. A significant correlation was found between the volume of distribution and ESR (p<0.05, r=0.844). Moreover, drug clearance had a significant inverse correlation with serum lactate (p<0.05, r=-0.603). No other significant correlations were found. CONCLUSIONS ESR and serum lactate were identified as useful predictors of amikacin pharmacokinetics in critically ill patients with intra-abdominal sepsis and may help guide the selection of appropriate empirical dosing.