Cefazolin concentration in surgically created wounds treated with negative pressure wound therapy compared to surgically created wounds treated with nonadherent wound dressings.

OBJECTIVE To compare cefazolin concentrations in biopsied tissue samples collected from surgically created wounds treated with negative pressure wound therapy to those collected from surgically created wounds treated with nonadherent dressings. STUDY DESIGN Prospective, controlled, experimental study. ANIMALS Adult female spayed Beagles (n = 12). METHODS Full thickness cutaneous wounds were created on each antebrachium (n = 24). Immediately after surgery, cefazolin (22 mg/kg intravenously [IV]) was administered to each dog and continued every 8 hours during the study. The right wound was randomly assigned to group I or group II whereas the wound on the contralateral antebrachium was assigned to the other group. Group I wounds were treated with negative pressure wound therapy (NPWT) and group II wounds were treated with nonadherent dressings for 3 days. Dressings were changed and tissue biopsies obtained from wound beds at 24 hours intervals for both groups. Cefazolin wound tissue and plasma concentrations were measured by liquid chromatography mass spectrometry (LC-MS/MS). Blood samples for measuring plasma cefazolin concentrations were collected before biopsy sampling. At the time of surgery and at each subsequent bandage change, wound beds were swabbed and submitted for aerobic and anaerobic culture. RESULTS After initiating cefazolin treatment, wound tissue antibiotic concentrations between treatment groups were not significantly different at any sampling time. Similarly, after initiating cefazolin treatment, plasma cefazolin concentrations were not significantly different at any sampling time for individual dogs. CONCLUSIONS Using a canine experimental model, NPWT treatment of surgically created wounds does not statistically impact cefazolin tissue concentrations when compared with conventional nonadherent bandage therapy.