Background: Therapeutic drug monitoring (TDM) of vancomycin is widely recommended for clinical treatment. The purpose of this study was designed to investigate the clinical implication of vancomycin TDM in patients undergoing surgery for gastrointestinal cancer requiring mechanical ventilation.
Methods: We included 78 patients who underwent surgery for gastrointestinal cancer. And all the patients included in this study were 18 years of age or older and were treated with intravenous vancomycin therapy for more than 2 days due to documented or suspected gram-positive bacterial infections, and have at least one available vancomycin plasma concentration. Based on whether the initial vancomycin concentration achieved the target trough concentration, the patients were divided into early and delayed groups and the clinical factors were compared between two groups.
Results: The research revealed that the patients undergoing surgery for gastrointestinal cancer had significantly lower initial vancomycin trough concentrations (median [IQR]: 6.90[5.28-11.20] mg/L). The duration of mechanical ventilation in early group was considerably shorter compared with delayed group (χ2=4.532; p < 0.05; Fig 2E). Propensity score weighting further confirmed that the duration of mechanical ventilation (χ2=6.607; p < 0.05; Fig 2F) and duration of vasoactive agent (χ2=6.106; p < 0.05; Fig 2D) was considerably shorter compared with delayed group. Multivariate regression analysis revealed that the Cys-C was the most important variable for vancomycin target trough achievement (odds ratio, 5.274; 95% CI, 1.780 to 15.627; p=0.003)
Conclusions: The serum initial trough concentration of vancomycin was significantly reduced in patients undergoing surgery for gastrointestinal cancer. Minimizing the time to initial vancomycin target trough can improve clinical outcomes in Gram-positive bacterial infections. The Cystatin C (Cys-C) level is a potentially valuable parameter for predicting the vancomycin concentration and Cys-C inclusive dosing model is warranted.