Necrotizing soft tissue infections (NSTIs) encompass three primary diagnoses: Necrotizing Fasciitis, Fournier's Gangrene and Gas Gangrene. These soft tissue infections have previously been considered separately, but due to the similarity of underlying pathogens, treatment, and associated illness severity, they have more recently been studied together. NSTIs are rare and life-threatening, with mortality as high as 73%, but with an average reported mortality of 25-39%. Given the rapidity of tissue destruction as well as the frequent sepsis and multisystem organ failure, NSTIs morbidity and mortality is very time sensitive to interventions. Standard therapy has consisted of surgery, antibiotics, and intensive peri-operative care. However, over the last 30 years there has been increasing use of adjunctive hyperbaric oxygen therapy (HBOT) to improve mortality and morbidity outcomes in NSTI. We are proposing a two-center, retrospective, case-control study of NSTI patients presenting to Regions Hospital and Hennepin County Medical Center over the last 10 years. Both Regions and HCMC are level one trauma centers with burn units, and HCMC has the capacity to treat patients with HBOT. We are comparing patients with NSTI who receive standard therapy and HBOT to those who receive standard therapy alone to determine (1) if those patients have a lower odds of inpatient mortality and (2) if those patients differ from patients who receive standard therapy alone in (a) the number of debridements received, (b) the length of time spent in the ICU, and (c) their overall length of inpatient stay.