DETERMINANTS OF MORTALITY FOR NECROTIZING SOFT-TISSUE INFECTIONS

Objective The authors determined the risk factors of mortality in pati ents with necrotizing soft-tissue infections (NSTIs) and examined the incidence and mortality from NSTI secondary to Streptococcus pyogenes. Methods All patients with NSTIs who were treated between January 1989 and June 1994 were analyzed for presentation, etiology, factors impor tant in pathogenesis and treatment, and mortality. Results Sixty-five patients were identified with NSTIs secondary to postoperative wound c omplications (18), trauma (15), cutaneous disease (15), idiopathic cau ses (10), perirectal abscesses (3), strangulated hernias (2), and subc utaneous injections (2). Necrotizing soft-tissue infections were polym icrobial in 45 patients (69%). S. pyogenes was isolated in only 17% of the NSTls, but accounted for 53% of monomicrobial infections, Eight o f ten idiopathic infections were caused by a single bacterium (p = 0.0 005), whereas 82% of postoperative infections were polymicrobial. An a verage of 3.3 operative debridements per patient and amputation in 12 patients were necessary to control infection, The overall mortality wa s 29%; mortality from S. pyogenes infection was only 18%. The average time from admission to operation was 90 hours in nonsurvivors versus 2 5 hours in survivors (p = 0.0002). Other risk factors previously assoc iated with the development of NSTls did not affect mortality. Conclusi ons Early debridement of NSTI was associated with a significant decrea se in mortality. S. pyogenes infection was the most common cause of mo nomicrobial NSTI, but was not associated with an increased mortality.