Influence of vancomycin on renal function in critically ill patients after cardiac surgery: continuous versus intermittent infusion.

BACKGROUND: Vancomycin is frequently used in clinical practice to treat severe wound and systemic infections caused by Gram-positive bacteria after cardiac surgery. The drug is excreted almost entirely by glomerular filtration and might exhibit nephrotoxic side effects. This study compared the nephrotoxic impact of vancomycin during continuous versus intermittent administration.

METHODS: The authors analyzed 149 patients admitted to the intensive care unit during a 5-yr period. All patients were treated at the intensive care unit after elective open heart surgery. Thirty patients received a dosage of 1325 +/- 603 mg/d vancomycin (range 300-3400 mg/d) by intermittent infusion, and 119 patients received a mean dosage of 1935 +/- 688 mg/d (range 352-3411 mg/d) by continuous infusion.

RESULTS: Nephrotoxicity occurred in 11 patients (36.7%) in the intermittent treatment group and in 33 patients (27.7%) in the continuous treatment group (P = 0.3; 95% CI = 0.283). Continuous veno-venous hemofiltration after vancomycin administration was required for 9 patients (9 of 30; 30%) in the intermittent treatment group and for 28 (28 of 119; 23.5%) in the continuous treatment group (P = 0.053; 95% CI = 0.256). A change of one unit (1 mg/l) in vancomycin serum concentration (DeltaVancoC) induced an average change of 0.04 mg/dl in creatinine (DeltaCrea) in the intermittent treatment group versus 0.006 mg/dl in the continuous treatment group (P < 0.001).

CONCLUSIONS: The data show that both the intermittent and also the continuous application modality of vancomycin are associated with deterioration of renal function in critically ill patients after cardiac surgery. However, continuous infusion showed the tendency to be less nephrotoxic than the intermittent infusion of vancomycin.