Necrotizing soft tissue infections. Risk factors for mortality and strategies for management

Abstract

Objective: The authors evaluate in a retrospective fashion the factors influencing outcome in a large group of patients presenting with necrotizing soft tissue infections, and, based on this analysis, propose a plan for optimal care of such patients.

Summary background data: In many smaller series of patients with necrotizing soft tissue infections, similar analyses of risk factors for mortality have been performed, producing conflicting conclusions regarding optimal care. In particular, debate exists regarding the impact of concurrent physiologic derangements, type and extent of infection, and the role of hyperbaric oxygen in treatment.

Methods: A retrospective chart review of 198 consecutive patients with documented necrotizing soft tissue infections, treated at a single institution during an 8-year period, was conducted. Using a model for logistic regression analysis, characteristics of each patient and his/her clinical course were tested for impact on outcome.

Results: The mortality rate among the 198 patients was 25.3%. The most common sites of origin of infection were the perineum (Fournier's disease; 36% of cases) and the foot (in diabetics; 15.2%). By logistic regression analysis, risk factors for death included age, female gender, extent of infection, delay in first debridement, elevated serum creatinine level, elevated blood lactate level, and degree of organ system dysfunction at admission. Diabetes mellitus did not predispose patients to death, except in conjunction with renal dysfunction or peripheral vascular disease. Myonecrosis, noted in 41.4% of the patients who underwent surgery, did not influence mortality.

Conclusions: Necrotizing soft tissue infections represent a group of highly lethal infections best treated by early and repeated extensive debridement and broad-spectrum antibiotics. Hyperbaric oxygen appears to offer the advantage of early wound closure. Certain markers predict those individuals at increased risk for multiple-organ failure and death and therefore assist in deciding allocation of intensive care resources.