Soft tissue infection: propensity score matching of outcome with or without hyperbaric treatment

Introduction: Skin and soft tissue infections (SSTIs) are a significant source of morbidity and mortality for hospitalized patients. Hyperbaric oxygen (HBO) therapy is offered as an adjunct to standard treatments at some centers, but the evidence for benefit in clinical practice in the literature is limited. Methods: This retrospective study involved adult patients who were admitted to a specialized Soft Tissue Service in 2019-2020 at a quaternary center. Logistic regression was performed on 18 factors to calculate propensity score for the need of hyperbaric treatment. Patients with soft tissue infection undergoing HBO were 1:1 propensity score matched with those that did not undergo HBO therapy. Clinical status, surgical treatments, and outcomes for each group were then examined. Results: Sixty-eight patients per group were analyzed. Patients were well-matched using demographic and clinical factors. When comparing the HBO groups versus the controls the median [IQR] SOFA score (2 [0,5], 2 [1,8]), mean (SD) LRINEC (7.5 (3), 7.3 (0.3)), serum lactate (2.0 (1), both), shock index (0.8 (0.2), 0.8 (0.3)), positive blood culture (3%, 1.5%), positive wound cultures (both 85%), closure at first debridement (16%, 22%), and rates of major amputation (9%, 15%) were not significantly different between the groups (all p>0.41). However, the HBO group had a significantly higher median number of debridement (3 [2,4], 2 [2,3]; p=0.008) and a longer median length of stay (14 [9-25], 10 [7-18] days; p=0.018). HBO patients were more likely to be discharged home as opposed to rehab or nursing facility (38% (59), 33% (49)), but was not significant (p=0.49). There was no significant difference in mortality between the two groups (3% (4), 4% (6); p=0.99). Conclusions: Patients with SSTI undergoing HBO had similar mortality to propensity-score matched patients who did not receive HBO, and a mean longer length of stay of 4 days. This difference could be due to the number of days required for HBO sessions. However, HBO patients were less likely to undergo a major amputation and more likely to be discharged home following treatment, although these differences were clinically significant but were not statistically significant. Further studies with large sample sizes are necessary.