Evaluation of the Effect of Mechanical Ventilation on the Pharmacokinetic Parameters of Vancomycin in Intensive Care Patients: A Prospective Cohort Study

Objective: Intensive care unit (ICU) patients on mechanical ventilation, in particular, may experience changes in pharmacokinetics due to alterations in cardiac output and organ blood flow. This study aims to evaluate the effects of mechanical ventilation on the steady-state pharmacokinetic changes of vancomycin. Methods: In this prospective cohort study, eligible patients were enrolled into either the ventilated or non-ventilated group. Demographic and clinical data were gathered, and peak and trough blood samples were collected to measure their levels. Additional pharmacokinetic parameters were calculated using appropriate formulas. Findings: A total of 39 ICU patients were enrolled in the final analysis. Of these, 32 matched patients were divided into two equal groups: ventilated and nonventilated. None of the pharmacokinetic parameters, including peak plasma concentration ( P = 0.878), trough plasma concentration ( P = 0.437), volume of distribution ( P = 0.468), K ( P = 0.234), t ½ ( P = 0.266), clearance ( P = 0.709), and daily area under the curve ( P = 0.418), were significantly different between the two groups. Bivariate correlation analysis showed a significant correlation between estimated glomerular filtration rate, acute physiology and chronic health evaluation II score, and C-reactive protein (CRP) level with vancomycin pharmacokinetic parameters. Furthermore, significant effects of augmented renal clearance (ARC) on vancomycin pharmacokinetics were determined. Conclusion: The key finding of this study was that ARC significantly impacted vancomycin serum levels, resulting in subtherapeutic concentrations in 23.1% of patients. High CRP levels also significantly correlated with increased vancomycin distribution volume, emphasizing the role of inflammation. These findings underscore the importance of personalized vancomycin dosing, taking into account factors such as ARC and inflammation, to improve patient outcomes. However, due to the small sample size, further studies with larger cohorts are necessary.