RESUMO
BACKGROUND: Vancomycin trough levels are frequently subtherapeutic in intensive care unit (ICU) patients. The aim of this study was to identify patients at risk of therapeutic failure defined as vancomycin area-under-the-curve0-24 /minimum inhibitory concentration (AUC0-24 /MIC) <400, and to examine possible effects of different MICs, the variability in renal clearance and continuous renal replacement therapy (CRRT), and the relevance of vancomycin therapy. METHODS: A prospective observational study of ICU patients ≥ 18 years at initiation of vancomycin therapy was conducted from May 2013 to October 2015. The patients were divided into four groups according to renal function and CRRT-mode as follows: normal- or augmented renal clearance and continuous venovenous hemodialysis or -hemofiltration. Vancomycin peak and trough levels were measured at 24, 48, and 72 hours after therapy initiation. Relevance of vancomycin therapy was retrospectively evaluated based on microbiological results. RESULTS: Eighty-three patients were included, median age 54.5 years, 74.5% male, SAPS II score 46, and 90 day mortality 28%. Vancomycin therapy was initiated on ICU-day 8 (IQR, 5-12), with a median treatment time of 7.5 (IQR, 5-12) days. AUC0-24 /MIC > 400 was reached in 81% and 8% with MIC = 1 and 2 mg/L respectively. The CRRT groups had higher AUC0-24 /MIC-ratios than the non-CRRT groups (P < .001). Augmented renal clearance increased the risk of AUC0-24 /MIC < 400, independent of MIC-value. Initiation of vancomycin therapy was retrospectively considered relevant in 28 patients (34%). CONCLUSION: A MIC-value >1 mg/L and augmented renal clearance, were factors increasing the risk of therapeutic failure. Vancomycin treatments could have been omitted or shortened in most of these patients.
