A. Louis1, S. Savage2, W. Li2, G. Utter3, S. Ross4, B. Sarani5, T. Duane6, P. Murphy7, M. Zielinski8, J. Tierney9, T. Schroeppel10, L. Kobayashi11, K. Schuster12, L. Timsina2, M. Crandall1 1University of Florida College of Medicine Jacksonville,Surgery,Jacksonville, FL, USA 2Indiana University School Of Medicine,Surgery,Indianapolis, IN, USA 3University Of California – Davis,Surgery,Sacramento, CA, USA 4Cooper University Hospital,Surgery,Camden, NJ, USA 5George Washington University School Of Medicine And Health Sciences,Surgery,Washington, DC, USA 6JPS Health Network,Surgery,Fort Worth, TX, USA 7University of Western Ontario,Surgery,London, ON, Canada 8Mayo Clinic,Surgery,Rochester, MN, USA 9University Of Colorado Denver,Surgery,Aurora, CO, USA 10University of Colorado,Surgery,Colorado Springs, CO, USA 11University Of California – San Diego,Surgery,San Diego, CA, USA 12Yale University School Of Medicine,Surgery,New Haven, CT, USA
Introduction: Skin and soft tissue infections (STIs) run the spectrum from mild cellulitis to life-threatening necrotizing infections. The severity of illness may be affected by a variety of factors including organism involved and patient comorbidities. The American Association for the Surgery of Trauma (AAST) has spent the last five years developing grading scales for impactful Emergency General Surgery (EGS) diseases, including STIs. The purpose of this study was to characterize patient and infection factors associated with increasing severity of STI using the AAST EGS grading scale.
Methods: This study was a retrospective multi-institutional trial, with each of 12 centers contributing 100 patients to the data set. Patient demographics, comorbidities and infection data were collected on each patient, as were outcomes including management strategies, mortality and hospital and intensive care unit (ICU) length of stay (LOS). Data were compared using Student’s t-test and Wilcoxon Rank Sum tests where appropriate. Simple and multivariate logistic regression, as well as ANOVA, were also used in analysis.
Results:1,140 patients were included in this analysis. The mean age of the cohort was 53 years (SD 19) and 68% of the patients were male. Hospital stay and mortality risk increased with STI grade (Table 1). The only statistical difference was noted between Group 3 and Group 5 (p=0.002). Higher EGS grade STIs were significantly associated with infection by Gram Positive Organisms (GPC) (when compared to Gram Negative Rods (GNR); OR 0.09, 95% CI 0.06-0.14, p<0.001 for Grade 5. Polymicrobial infections were also significantly more common with higher grade STI (compared to STI Grade 1: Grade 2 OR 2.29 (95% CI 1.18-4.41); Grade 3 OR 5.11 (95% CI 3.12-8.39); Grade 4 OR 4.28 (95% CI 2.49-7.35); Grade 5 OR 2.86 (95% CI 1.67-4.87); all p-values were less than 0.001. GPC infections were associated with significantly more surgical debridements per patient (GNR 1.64 (SD 1.83) versus 2.37 (SD 2.7), p < 0.001). There were no significant differences in preponderance of organism based on region of the country except in Canada, which had a significantly higher incidence of GNRs compared to GPCs.
Conclusion:This study provides additional insight into the nature of STIs. Higher grade STIs are dominated by GPCs, which also require more aggressive surgical debridement. Understanding the natural history of these life-threatening infections will allow centers to plan their operative and antibiotic approach more effectively.
