Transfer Is Associated with a Higher Mortality Rate in Necrotizing Soft Tissue Infections

Identifying patients with difficult-to-treat acute bacterial skin infections

PURPOSE OF REVIEW

The early recognition of acute bacterial skin infections (ABSIs) and their swift and adequate care are the major determinants of success. The features that can hamper or delay surgical and medical management can lead to 'difficult-to-treat' ABSIs.

RECENT FINDINGS

Delayed diagnosis and belated management are the key obstacles to be overcome. Clinicians should be careful about underestimating the severity of ABSIs and overlooking comorbidities, especially immunosuppression. Many conditions can lead to delayed source control, including a misdiagnosis, interhospital transfers, delayed re-exploration, or extensive injuries. Difficult therapeutic issues can occur, including rapidly destructive infections from highly pathogenic microorganisms (Group-A-streptococci, Vibrio spp., Clostridium spp. and Staphylococcus aureus ) or inadequate antibiotic therapy resulting from multidrug-resistant bacteria. Impaired pharmacokinetic capacities of antibiotic agents should also be considered as a source of clinical failure due to insufficient antimicrobial activity at the site of infection.

SUMMARY

Microbiological samples should be used for guiding antimicrobial therapy. Risk factors for multidrug-resistant bacteria should be considered, including local epidemiology and comorbidities. The optimization of antibiotic therapy should be achieved. Optimized care should be achieved through multidisciplinary management involving professionals with sufficient and appropriate training.

Necrotising soft-tissue infections

The incidence of necrotising soft-tissue infections has increased during recent decades such that most physicians might see at least one case of these potentially life-threatening infections in their career. Despite advances in care, necrotising soft-tissue infections are still associated with high morbidity and mortality, underlining a need for continued education of the medical community. In particular, failure to suspect necrotising soft-tissue infections, fuelled by poor awareness of the disease, promotes delays to first surgical debridement, amplifying disease severity and adverse outcomes. This Review will focus on practical approaches to management of necrotising soft-tissue infections including prompt recognition, initiation of specific management, exploratory surgery, and aftercare. Increased alertness and awareness for these infections should improve time to diagnosis and early referral to specialised centres, with improvement in the prognosis of necrotising soft-tissue infections.

Predictors of Mortality and Amputation in Patients With Necrotizing Soft Tissue Infections of the Upper Extremity

PURPOSE

Necrotizing soft tissue infection (NSTI) of the upper extremity is characterized by rapid progression, local tissue necrosis, systemic toxicity, and a high mortality rate. The negative consequences of debridement are balanced against preservation of life and limb. The primary objective of this study was to identify predictors of mortality in upper extremity NSTI. Secondary objectives were to identify predictors of amputation, final defect size, length of stay, and readmission within 30 days.

METHODS

An institutional registry for patients with NSTI was retrospectively queried from a single tertiary center covering a large referral population. Data on confirmed upper extremity NSTI were used to determine patient characteristics, infection data, and operative factors. Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) and Quick Sequential Organ Failure Assessment (qSOFA) scores were calculated from primary data to provide a measure of clinical severity. Bivariate screening identifying possible predictors of mortality and multivariable regression was performed to control for confounding. Similar analyses were performed for amputation, final defect size, and readmission within 30 days.

RESULTS

A total of 99 patients met the study criteria. In-hospital mortality occurred in 12 patients, and amputation was performed in 7 patients. Etiology, causative organism, and clinical severity scores were variable. Logistic regression showed mortality to be independently predicted by vasopressor dependency outside of operative anesthesia. The relatively low number of case events, limited sample size, and multiple comparisons limited the evaluation of lesser predictor variables. The LRINEC score did not strongly predict amputation or death in this series.

CONCLUSIONS

Necrotizing soft tissue infection of the upper extremity carries risk of mortality and amputation, and effective treatment requires prompt recognition, early goal-directed resuscitation, and early debridement. The strongest independent predictor of in-hospital mortality was vasopressor dependence outside operative anesthesia. The LRINEC score did not strongly predict death or amputation in upper extremity NSTI.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Characterization of Necrotizing Soft Tissue Infections in Obese and Non-Obese Patients

Background: The impact of obesity on the pathogenesis and prognosis of necrotizing soft tissue infections (NSTIs) is unclear. The goal of this study was to characterize differences in NSTI presentation and outcomes by obesity status. Patients and Methods: A retrospective analysis of institutional data for patients diagnosed with NSTIs were identified (n = 619; 2011-2020). Patients were divided based on obesity (body mass index [BMI] ≥ 30 kg/m²) and non-obese (BMI <30 kg/m²). Primary outcomes included NSTI location, micro-organisms, and index hospitalization data. Multiple logistic regression was used to model predictors of in-hospital and 90-day mortality. Results: The obese cohort (n = 390; 63%) had higher rates of congestive heart failure and type 2 diabetes mellitus. There were no differences in length of stay, mortality, or discharge disposition between groups. A higher rate of respiratory failure was observed in the obese versus non-obese group (36.7% vs. 20.9%; p < 0.0005). The obese cohort was associated with perineal (40.8% vs. 27.0%) and torso NSTIs (20.9% vs. 15.8%; p < 0.005) but reduced staphylococcal (19.2% vs. 27.4%; p = 0.02) and group A streptococcal (2.6% vs. 6.5%; p = 0.03) infections, and increased polymicrobial infections. Class 2 obesity was a negative predictor for in-hospital mortality (odds ratio [OR], 0.1; 95% confidence interval [CI], 0.03-0.5) and 90-day mortality (OR, 0.3; 95% CI, 0.1-0.8), when adjusting for demographic data, type of infection, and baseline comorbidities. Conclusions: Necrotizing soft tissue infections in obesity may present with unique distributions and microbial characteristics. Class 2 obesity may exhibit a survival benefit compared with non-obese patients, suggestive of an obesity paradox.

Transfer Status and 90-Day Mortality in ICU Patients with Sepsis: A Propensity Matched Analysis

BACKGROUND

Timely identification and management of sepsis in surgical patients is crucial, and transfer status may delay optimal treatment of these patients. The objective of this study was to compare in-house and 90-day mortality between patients primarily admitted or transferred into the surgical ICU (SICU) at a tertiary referral center.

MATERIAL AND METHODS

All patients admitted to the SICU with a diagnosis of sepsis (Sepsis III) were reviewed at a single institution between 2014 to 2019 (n = 1489). Demographics, comorbidities, and sepsis presentation were compared between transferred (n = 696) and primary patients (n = 793). Primary outcomes evaluated were in-house and 90 day mortality in an unmatched and propensity score matched cohorts. A P value < 0.05 was considered statistically significant.

RESULTS

Transfer patients were more likely to have obesity (60% versus 49%, P < 0.005), a higher median SOFA (6 (4-8) versus 5 (3-8), P = 0.007), and require vasopressors on admission (42% versus 35%, P = 0.004). Compared to primary patients, transfer patients exhibited higher rates of respiratory failure (76% versus 69%, P = 0.003), in-house (30% versus 17%, P < 0.005), and 90 day mortality (36% versus 24%, P < 0.005). After matching, transferred patients were associated with 75% and 83% increased odds of in-house and 90 day mortality after controlling for age, sex, race, comorbidities, BMI, and sepsis severity.

CONCLUSIONS

Transfer status is associated with an over 80% increase in the odds of 90 day mortality for patients admitted to the SICU with sepsis. Aggressive patient identification and earlier transfer of those at higher risk of death may reduce this effect.