Background: Appropriate vancomycin dosing is needed to treat patients with multiple trauma in the intensive care unit (ICU). The trough level of vancomycin in the trauma intensive care unit (TICU) patients was lower than that of other ICU patients at Ajou University Hospital, a 1,084 bed tertiary hospital. A lower vancomycin concentration may be associated with treatment failure in TICU patients. We evaluated the factors affecting vancomycin levels and studied pharmacokinetics of vancomycin in TICU patients compared to medical ICU (MICU) patients to guide appropriate dosing of vancomycin.
Methods: We retrieved the therapeutic drug monitoring (TDM) database at the Ajou University Hospital pharmacy retrospectively to select appropriate cases. Patients who were admitted to the TICU or MICU from January 2015 to December 2015 were selected. All patients received at least three doses of vancomycin intravenously and serum vancomycin levels were expected to be steady state. After the expected steady state, the serum vancomycin trough levels and TDM were checked. Patients < 19 years old, those with end stage renal disorder on intermittent hemodialysis or continuous ambulatory peritoneal dialysis and pregnant woman were excluded. Seventy-six cases/56 patients from the TICU and 96 cases/89 patients from the MICU were analyzed. We reviewed patient medical history, laboratory results, use of vancomycin and other drugs, clinical findings, and pharmacokinetics of vancomycin. Continuous variables are expressed as means ± standard deviation, and categorical variables are presented as frequencies and percentages. Group comparisons were analyzed independently by Student’s t-test for continuous variables and the chi-square test for categorical variables. Pearson’s correlation analysis was performed to evaluate the correlations, and the interrelated effects of each variable were analyzed by multiple linear regression. A two-tailed p-value < .05 denoted a significant difference.
Results: Many characteristics of patients were significantly different between the TICU and MICU, particularly body weight (71.93 ± 14.78, 58.36 ± 19.88; kg; P < .0001) and weight-associated factors, including overweight, overweight rate, body mass index (BMI), body surface area (BSA), and creatinine clearance (143.52 ± 69.41, 97.24 ± 63.69; mg/dl; P < .0001). The pharmacokinetics of vancomycin in the non-continuous renal replacement therapy (CRRT) group revealed the lots of difference between the two ICUs, and vancomycin clearance was higher in TICU patients than that in the MICU patients (74.25 ± 27.99, 53.74 ± 23.91; ml/min; P < .0001). No significant difference in vancomycin clearance was observed in the CRRT group (35.42 ± 11.03, 30.96 ± 9.64; ml/min; P = .215). The only factor associated with vancomycin clearance in the non-CRRT group was creatinine clearance (coefficient 0.156; P = .017), and no factor was associated with vancomycin clearance in the CRRT group.
Conclusions: Patients with multiple trauma in the ICU were heavier than other ICU patients because of intensive fluid therapy. A more appropriate dose of vancomycin is required in patients with multiple trauma, depending on the creatinine clearance and actual body weight, and therapeutic vancomycin levels should be monitored. Vancomycin can be infused in fixed doses for patients undergoing CRRT, regardless of the type of ICU or patient characteristics.