Analysis of Vancomycin monitoring in an intensive care unit of a hospital in the Southern Zone of São Paulo

Abstract

Introduction: ICU patients face a high risk of infections caused by multidrug-resistant microorganisms, with vancomycin being an essential therapeutic option for resistant gram-positive bacteria. Its efficacy depends on the AUC/MIC ratio (≥400), but its narrow therapeutic window increases the risk of nephrotoxicity. Monitoring serum vancomycin concentrations is crucial for early dose adjustments and minimizing adverse events, especially in critically ill patients. Objective: To analyze the monitoring of serum vancomycin concentrations and correlate the timing of vancomycin measurement with the occurrence of adverse events in critically ill patients. Methods: This observational and retrospective study was conducted in a general hospital in the southern region of São Paulo, from July 2023 to July 2024, with data collected through electronic medical record review. ICU patients treated with vancomycin, either empirically or directed, were stratified into three groups based on the timing of serum monitoring. Descriptive statistical analysis emphasized relevant clinical and laboratory variables. Results: A total of 102 patients were analyzed. In Group 1, 25% of the 40 patients reached the therapeutic target, showing lower rates of adverse events. In Group 2, 90.9% of the 11 patients with concentrations <15 µg/mL exhibited elevated leukocytes and CRP, indicating a higher prevalence of underdosing. In Group 3, 72.2% of the 18 patients showed increased serum creatinine, demonstrating a greater renal impact. Conclusion: Early monitoring of serum vancomycin concentrations, after the third or fourth dose, was associated with better clinical outcomes, including lower rates of adverse events and a higher proportion of patients achieving the ideal therapeutic range.