Vancomycin wound penetration in open-heart surgery patients receiving negative pressure wound therapy for deep sternal wound infection

Abstract

Introduction: It is hypothesized that systemically administered antibiotics penetrate wound sites more effectively during negative pressure wound therapy (NPWT). However, there is a lack of clinical data from patients who receive NPWT for deep sternal wound infection (DSWI) after open-heart surgery. Here, we evaluated vancomycin penetration into exudate in this patient group. Patients and methods: For this prospective observational study, we enrolled 10 consecutive patients treated with NPWT for post-sternotomy DSWI. On the first sampling day, serum and exudate samples were synchronously collected at 0 (pre-dose), 0.5, 1, 2, 3 and 6 h after vancomycin administration. On the following three consecutive days, additional samples were collected, only before vancomycin administration. Results: The ratio of average vancomycin concentration in wound exudate to in serum was higher for free (unbound) (1.51 ± 0.53) than for total (bound + unbound) (0.91 ± 0.29) concentration (p = 0.049). The percentage of free vancomycin was higher in wound exudate than serum (0.79 ± 0.19 vs. 0.46 ± 0.16; p = 0.04). Good vancomycin wound penetration was maintained on the following three days (vancomycin trough exudate-to-serum concentration ratio > 1). The total hospital stay was significantly longer in patients with DSWI (46 ± 11.6 days) versus without DSWI (14 ± 11.7 days) (p < 0.001). There was no in-hospital or 90-day mortality. Two patients experienced late DSWI recurrence. All-cause mortality was 4.8% during a median follow-up of 2.5 years. Conclusion: Vancomycin effectively penetrates wound exudate in patients receiving NPWT for DSWI after open-heart surgery. The protocol for this study was registered at ClinicalTrials.gov on July 16, 2024 (NCT06506032).