856 A Pilot Study of a Point-of-care Wound Bed Assay to Predict Graft Take

Introduction Deciding when to graft a burn wound is instrumental in acute reconstruction. A technology capable of predicting autograft success would help optimize timing of initial debridement and grafting. In prior work, members of our team developed a point-of-care proteinase assay capable of predicting delayed wound healing in chronic wounds. In the work reported here, we seek to quantify these proteolytic enzymes in acute burn wounds in an effort to ultimately determine whether a quantitative assessment of proteinase activity in a burn wound might predict successful healing of autograft. Methods Eight burn patients were taken to the operating room for autografting. Tissue samples were obtained from unique sites, as well as swabs of wounds pre- and post-excision. A point-of-care proteinase assay determined initial rates of fluorescence, which correlates with the amount of proteolytic enzyme activity. Autograft sites were assessed after two weeks, with ≥50% take considered successful and < 50% take deemed unsuccessful. Initial rates of fluorescence were compared. These groups were analyzed using two-sided student’s t tests, with p< 0.05 identified as significant. Results The pre-excision group initial rate was significantly higher than the post-excision group (p=0.0006). The tissue group initial rate was also significantly higher than the post-excision group (p = 0.0028). We also compared pre-excision initial rates of enzymatic activity between successful autografts (n=10, 18.34±20.90 RFU/min) and unsuccessful autografts (n=5, 4.32±4.62 RFU/min) with p = 0.169. Conclusions Multiple findings indicate the potential of this assay to differentiate burn wounds based on proteinase activity. Pre-excision tissue beds contained significantly higher rates of proteinase activity compared to excised and debrided tissue beds (p = 0.0006). This is consistent with burn wound morphology, as proteolytic enzymes function to debride damaged tissue and promote angiogenesis in acute wounds. Interestingly, initial rates of proteolytic enzymatic activity in pre-excised wounds of successful autografts trended towards significance compared to unsuccessful autografts (p = 0.169), suggesting that these proteolytic enzymes reflect an overall healthy wound bed, the presence of which could portend a heightened chance for autograft success. Applicability of Research to Practice This pilot study confirms the presence of proteinase activity in acute burn wounds utilizing a point-of-care test. Future work will investigate whether this test can assist physicians in predicting amenability of burn wounds to autografting.