Currently, there is a lack of proper tools to evaluate the severity and prognosis of NSTI in individual patients. This results in necessary, yet sometimes overzealous surgical debridement, culminating in prolonged patient rehabilitation and invalidity. Hyperbaric oxygen therapy (HBOT) may be added as adjunctive therapy of NSTI. However, there is no clear understanding of the effectiveness of HBOT on NSTI. The investigators seek to remedy these two issues by examining multiple biomarkers over the course of several studies.