Prospective derivation and validation of a NECROtizing Soft tissue InfectionS (NECROSIS) score: An EAST multicenter trial.

BACKGROUND: Although several risk indices have been developed to aid in the diagnosis of NSTIs, these instruments suffer from varying levels of reproducibility and failure to incorporate key clinical variables in model development. The objective of this study was to derive and validate a clinical risk index score - NECROSIS - for identifying NSTIs in emergency general surgery (EGS) patients being evaluated for severe skin and soft tissue infections. METHODS: We performed a prospective study across 16 sites in the US of adult EGS patients with suspected NSTIs over a 30-month period. Variables analyzed included demographics, admission vitals and labs, physical exam, radiographic, and operative findings. The main outcome measure was the presence of NSTI diagnosed clinically at the time of surgery. Multivariate analysis was performed to identify independent predictors for the presence of NSTI using the Hosmer-Lemeshow test and the Akaike information criteria. RESULTS: Of 362 patients, 297 (82%) were diagnosed with a NSTI. Overall mortality was 12.3%. Multivariate analysis identified 3 independent predictors for NSTI: systolic blood pressure ≤ 120 mmHg, violaceous skin, and WBC ≥15 (x103/uL). Multivariate modelling demonstrated Hosmer-Lemeshow goodness of fit (p = 0.9) with a c-statistic for the prediction curve of 0.75. Test characteristics of the NECROSIS score were similar between the derivation and validation cohorts. CONCLUSION: NECROSIS is a simple and potentially useful clinical index score for identifying at-risk EGS patients with NSTIs. Future validation studies are warranted. LEVEL OF EVIDENCE: Diagnostic Tests or Criteria, Level III.

Fatal Clostridium septicum myonecrosis from gastric perforation: A case report.

Clostridial myonecrosis is a medical and surgical emergency which requires early and aggressive intervention to reduce mortality. We report a rare case of Clostridium septicum myonecrosis that disseminated hematogenously from a gastric perforation. The patient was afebrile and hemodynamically stable upon admission. He rapidly developed spontaneous clostridial myonecrosis and succumbed to septic shock 36 hours after presentation. In our extensive literature review this is the only case with blood cultures confirming Clostridium septicum bacteremia with a surgically confirmed gastric perforation source in the setting of spontaneous clostridial myonecrosis.

Ab initio identification of the nitrogen diffusion mechanism in silicon.

In this Letter, we present ab initio results identifying a new diffusion path for the nitrogen pair complex in silicon, resulting in an effective diffusivity of 67exp((-2.38 eV/kT) cm2/s. This nudged elastic band result is compared with other nitrogen diffusion paths and mechanisms, and is determined to have unmatched agreement with experimental results. It is also shown that careful consideration of total energy corrections and use of a fully temperature-dependent diffusion prefactor have modest but important effects on the calculation of diffusivity for paired and for interstitial nitrogen.