Trends in the Incidence and Treatment of Necrotizing Soft Tissue Infections: An Analysis of the National Hospital Discharge Survey

Assessing Second Debridement Timing and Mortality in Necrotizing Soft Tissue Infections

BACKGROUND

Patients with necrotizing soft tissue infection undergo an average of 4-5 debridements per hospital admission. Optimal timing for initial debridement is emergent. Second debridement is universally recommended to occur within 24 hours of the first, but no studies have successfully evaluated this time frame. Prior work has suggested that delays in second debridement are associated with increased mortality, and that few patients receive second debridement within 24 hours.

METHODS

We performed a retrospective cohort study at a single center from 01/01/08 to 09/01/2021. The explanatory variable was whether the subject received second debridement within 24 hours of initial debridement. The primary outcome was in-hospital mortality. Baseline characteristics were collected. Subjects were stratified into 2 groups by time between first and second debridement: <24 and ≥24 hours. Variables were compared using Fisher's exact and Wilcoxon rank-sum tests.

RESULTS

77 patients met inclusion criteria. The median overall time to second debridement was 40 hours. 12 subjects received second debridement within 24 hours (15.6%). There was no difference in in-hospital mortality between the <24 (n = 3, 25.0%) and ≥24-hour second debridement groups (n = 4, 6.2%; P = .07). The 2 groups did not differ by secondary outcomes, including total number of debridements, ICU LOS, or wound closure.

CONCLUSION

No difference in mortality was observed between subjects undergoing second debridement within 24 vs after 24 hours. Only 16% of subjects received second debridement within the recommended 24-hour time interval. Further study is required to identify the optimal timing of second debridement.

Bilateral non-contiguous necrotizing fasciitis of the lower extremities

Necrotizing fasciitis (NF) is an uncommon soft tissue infection. Multifocal-extremity NF is a rarity with high mortality rates. Herein we report a case of bilateral non-contiguous NF of the lower extremities due to Escherichia coli with a fatal outcome, stressing the necessity of rapid and aggressive intervention in suspected cases.

Re-Admission in Patients with Necrotizing Soft Tissue Infections: Continuity of Care Matters

Background: Necrotizing soft tissue infections (NSTIs) are rapidly progressive infections with high mortality and complication rates. The incidence of NSTIs has been increasing steadily whereas mortality has decreased; survivors have a high risk of re-hospitalization. We hypothesized that re-admission to the index hospital where the first admission occurred would be associated with better clinical outcomes compared with re-admission to a non-index hospital. Patients and Methods: We identified patients from the 2017 Nationwide Readmissions Database with an index admission for NSTIs and examined all-cause re-admissions within 90 days of discharge. We noted whether re-admission occurred at the index or a non-index hospital. Survey-weighted logistic regression identified factors associated with death at the first re-admission and re-admission to index hospital. We also compared patient outcomes between patients admitted to index versus non-index hospitals. Results: We identified 27,051 NSTI survivors, of whom 6,954 (25.7%) had an unplanned re-admission within 90 days. A large proportion of re-admission occurred at non-index hospitals (28.3%; n = 1,966). Factors associated with non-index re-admission included prolonged index length of stay, discharge to short-term hospital, and leaving against medical advice. Patients re-admitted to index hospitals had a lower mortality rate (4.7% vs. 6.7%; p = 0.003), lower admission costs (in $1000; 45 [23-88] vs. 50 [24-104]; p = 0.004) and higher discharge rate to home (55.7% vs. 48.6%; p < 0.001). Conclusions: More than one-quarter of re-admissions among NSTI survivors were to non-index hospitals. Continuity of care is important because re-admission to the index hospital was associated with better patient outcomes.

Associations between YKL-40 and markers of disease severity and death in patients with necrotizing soft-tissue infection

Background

Necrotizing soft-tissue infection (NSTI) is a severe and fast-progressing bacterial infection. Prognostic biomarkers may provide valuable information in treatment guidance and decision-making, but none have provided sufficient robustness to have a clinical impact. YKL-40 may reflect the ongoing pathological inflammatory processes more accurately than traditional biomarkers as it is secreted by the activated immune cells, but its prognostic yields in NSTI remains unknown. For this purpose, we investigated the association between plasma YKL-40 and 30-day mortality in patients with NSTI, and assessed its value as a marker of disease severity.

Methods

We determined plasma YKL-40 levels in patients with NSTI (n = 161) and age-sex matched controls (n = 65) upon admission and at day 1, 2 and 3.

Results

Baseline plasma YKL-40 was 1191 ng/mL in patients with NSTI compared with 40 ng/mL in controls (p < 0.001). YKL-40 was found to be significantly higher in patients with septic shock (1942 vs. 720 ng/mL, p < 0.001), and in patients receiving renal-replacement therapy (2382 vs. 1041 ng/mL, p < 0.001). YKL-40 correlated with Simplified Acute Physiology Score II (Rho 0.33, p < 0.001). Baseline YKL-40 above 1840 ng/mL was associated with increased risk of 30-day mortality in age-sex-comorbidity adjusted analysis (OR 3.77, 95% CI; 1.59–9.24, p = 0.003), but after further adjustment for Simplified Acute Physiology Score II no association was found between YKL-40 and early mortality.

Conclusion

High plasma YKL-40 to be associated with disease severity, renal-replacement therapy and risk of death in patients with NSTI. However, YKL-40 is not an independent predictor of 30-day mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06760-x.

Adjunctive hyperbaric oxygen treatment for necrotising soft-tissue infections: A systematic review and meta-analysis

INTRODUCTION

Surgical intervention, broad-spectrum antibiotics and intensive care support are the standard of care in the treatment of necrotising soft-tissue infections (NSTI). Hyperbaric oxygen treatment (HBOT) may be a useful adjunctive treatment and has been used for almost 60 years, but its efficacy remains unknown and has not been systematically appraised. The aim was to systematically review and synthesise the highest level of clinical evidence available to support or refute the use of HBOT in the treatment of NSTI.

METHODS

The review was prospectively registered (PROSPERO; CRD42020148706). MEDLINE, EMBASE, CENTRAL and CINAHL were searched for eligible studies that reported outcomes in both HBOT treated and non-HBOT treated individuals with NSTI. In-hospital mortality was the primary outcome. Odds ratio (ORs) were pooled using random-effects models.

RESULTS

The search identified 486 papers of which 31 were included in the qualitative synthesis and 21 in the meta-analyses. Meta-analysis on 48,744 patients with NSTI (1,237 (2.5%) HBOT versus 47,507 (97.5%) non-HBOT) showed in-hospital mortality was 4,770 of 48,744 patients overall (9.8%) and the pooled OR was 0.44 (95% CI 0.33-0.58) in favour of HBOT. For major amputation the pooled OR was 0.60 (95% CI 0.28-1.28) in favour of HBOT. The dose of oxygen in these studies was incompletely reported.

CONCLUSIONS

Meta-analysis of the non-random comparative data indicates patients with NSTI treated with HBOT have reduced odds of dying during the sentinel event and may be less likely to require a major amputation. The most effective dose of oxygen remains unclear.

Incidence, comorbidity and mortality in patients with necrotising soft-tissue infections, 2005-2018: a Danish nationwide register-based cohort study

OBJECTIVE

To assess the incidence, comorbidities, treatment modalities and mortality in patients with necrotising soft-tissue infections (NSTIs) in Denmark.

DESIGN

Nationwide population-based registry study.

SETTING

Denmark.

PARTICIPANTS

Danish residents with NSTI between 1 January 2005 and 31 August 2018.

MAIN OUTCOME MEASURE

Incidence of disease per 100 000 person/year and all-cause mortality at day 90 obtained from Danish National Patient Registry and the Danish Civil Registration System.

RESULTS

1527 patients with NSTI were identified, yielding an incidence of 1.99 per 100 000 person/year. All-cause 30-day, 90-day and 1-year mortality were 19.4% (95% CI 17.4% to 21.5%), 25.2% (95% CI 23.1% to 27.5%) and 30.4% (95% CI 28.0% to 32.8%), respectively. Amputation occurred in 7% of the individuals. Diabetes was the most predominant comorbidity affecting 43% of the cohort, while 26% had no comorbidities. Higher age, female sex and increasing comorbidity index were found to be independent risk factors of mortality. Admission to high-volume hospitals was associated with improved survival (OR 0.59, 95% CI 0.45 to 0.77). Thirty-six per cent received hyperbaric oxygen therapy (HBOT) as an adjunctive therapy. No change in overall mortality was found over the studied time period.

CONCLUSION

The present study found that in Denmark, the incidence of NSTI increased; mortality rates remained high and largely unaltered. Diabetes was the most common comorbidity, while higher age, female sex and increasing comorbidity index were associated to increased mortality. Survival was improved in those admitted to hospitals with more expertise in treating NSTI. In high-volume hospital, HBOT was associated with decreased odds for mortality.

[Necrotizing fasciitis-a surgical emergency]

Necrotizing fasciitis is a fulminant and potentially life-threatening infection of the skin and soft tissue. It is usually caused by a combination of different bacteria and is often due to assumed minor trauma. Clinically, only relatively insignificant skin changes are initially present, such as blistering or erythema. They are often accompanied by excessive pain. In the further course, the massive systemic reaction becomes predominant. The diagnosis of necrotizing fasciitis is primarily clinical, which can be supported by laboratory parameters (LRINEC score) and computed tomography imaging. Decisive for the prognosis is the immediate initiation of surgical treatment by radical debridement. Additionally, the calculated administration of a combination of different antibiotics should be initiated. As part of the further complex intensive care treatment, a regular reevaluation of the wounds is carried out. Multiple débridements are always necessary until plastic surgery for defect coverage can be carried out.

[Necrotizing fasciitis-a surgical emergency]

Necrotizing fasciitis is a fulminant and potentially life-threatening infection of the skin and soft tissue. It is usually caused by a combination of different bacteria and is often due to assumed minor trauma. Clinically, only relatively insignificant skin changes are initially present, such as blistering or erythema. They are often accompanied by excessive pain. In the further course, the massive systemic reaction becomes predominant. The diagnosis of necrotizing fasciitis is primarily clinical, which can be supported by laboratory parameters (LRINEC score) and computed tomography imaging. Decisive for the prognosis is the immediate initiation of surgical treatment by radical debridement. Additionally, the calculated administration of a combination of different antibiotics should be initiated. As part of the further complex intensive care treatment, a regular reevaluation of the wounds is carried out. Multiple débridements are always necessary until plastic surgery for defect coverage can be carried out.

Impact of a multidisciplinary care bundle for necrotizing skin and soft tissue infections: a retrospective cohort study

BACKGROUND

Necrotizing skin and soft tissue infections (NSTIs) require both prompt medical and surgical treatment. The coordination of multiple urgent interventions by care bundles has improved outcome in other settings. This study aimed to assess the impact of a multidisciplinary care bundle on management and outcome of patients with NSTIs.

METHODS

Patients with NSTIs admitted between 2006 and 2017 were compared according to admission before or after bundle implementation (2012-2013). This bundle consisted mainly in (1) the creation of a multidisciplinary task force; (2) management guidelines on empirical antibiotics, intensive care unit admission criteria, a triage algorithm to accelerate operating room access; and (3) an active communication policy. Patient recruitment and management were compared between pre- and post-implementation periods. Main outcome was day 60-censored hospital survival.

RESULTS

Overall, 224 patients were admitted: 60 before, 35 during, and 129 after bundle implementation. Admission after implementation was associated with increased yearly admissions (10 [8-13] vs 30 [24-43] patients/year, p = 0.014) and decreased mortality (30 vs 15%, HR = 0.49 [0.26-0.92]; p = 0.026) but was no longer a protective factor for mortality after adjustment on confounding factors (adjusted HR = 0.90 [0.43-1.88], p = 0.780). There was no significant difference regarding time to surgery (0 [0-1] vs 0 [0-1] days, p = 0.192) or rate of antibiotic treatment within 24 h (98% vs 99%, p > 0.99).

CONCLUSIONS

Implementation of a multidisciplinary care bundle for NSTIs was feasible, but in a retrospective study from an already experienced center was not associated with significantly increased survival after adjustment.

Obligate anaerobes are abundant in human necrotizing soft tissue infection samples - a metagenomics analysis

Necrotizing soft tissue infections (NSTIs) are associated with high morbidity and mortality and are increasing in incidence. Proper identification of the microbial causes of NSTIs is a crucial step in diagnosis and treatment, but the majority of data collected are culture based, which is biased against fastidious organisms, including obligate anaerobes. The goal of this study was to address this gap in knowledge by characterizing NSTI microbial communities through molecular diagnostics. We performed 16S rRNA sequencing on human NSTI samples and identified five genera most commonly found in NSTIs (Prevotella, Bacteroides, Peptoniphilus, Porphyromonas, and Enterococcus). We found that a >70% contribution of obligate anaerobes to the bacterial population distribution was associated with NSTI mortality, and that NSTI samples, from both survivors and non-survivors, had an increased relative abundance of gram negative bacteria compared to those of abscess patients. Based on our data, we conclude that obligate anaerobes are abundant in NSTIs and a high relative abundance of anaerobes is associated with a worse outcome. We recommend increasing anaerobe antibiotic coverage during the treatment of NSTIs even when anaerobes are not found by traditional clinical microbiology methods, and especially when there is a clinical suspicion for anaerobe involvement.

The mythos of laudable pus along with an explanation for its origin

The presence of pus is one of the most easily recognizable signs of an infection. However, for several centuries suppuration, known as ‘laudable pus,’ was believed to be a sign of a healthy, healing wound. This historical misconception can be explained by the difference in the presentation of a necrotizing soft tissue infection versus other more common skin and soft tissue infections. Chronic wound infections, due to pyogenic bacteria, typically produce large amounts of thick, whitish-yellow pus. On the other hand, necrotizing soft tissue infections, despite their severe mortality and morbidity, are devoid of pus in the traditional sense. What the ancient medical observers recognized was the fact that pus is not characteristic of this subset of incredibly severe infections. This is an important distinction to remember when evaluating an infection, even today.

Determinants of Home Discharge Among Survivors of Necrotizing Fasciitis: A Population-Level Analysis

BACKGROUND

The majority of patients with necrotizing fasciitis (NF) in the United Sates survive their illness, and there is increasing interest in addressing the ability of survivors to return to their community following hospitalization. However, there are no data on the factors affecting home discharge among survivors of NF.

METHODS

We used the Texas Inpatient Public Use Data File to conduct a retrospective population-based examination of hospitalizations with NF aged 15 years or older between 2001 and 2010. Multivariate logistic regression modeling was used to explore predictors of home discharge among hospital survivors.

RESULTS

There were 10,724 NF hospitalizations surviving to discharge during study period, of which 62.5% were discharged home. The following key predictors have adversely affected odds of home discharge (odds ratio and 95% confidence intervals): age ≥ 75 years (0.349 (0.292 - 0.417)), Medicare insurance (0.582 (0.510 - 0.663)), congestive heart failure (0.836 (0.719 - 0.972)), chronic liver disease (0.684 (0.522 - 0.895)), respiratory failure (0.464 (0.386 - 0.558)), neurological failure (0.573 (0.418 - 0.787)), and need for mechanical ventilation (0.339 (0.199 - 0.578)). Increased odds of home discharge were found among males (1.116 (1.058 - 1.285)), Hispanics (1.193 (1.056 - 1.349)), those lacking health insurance (2.161 (1.183 - 2.521)) or managed at a teaching hospital (1.264 (1.127 - 1.418)).

CONCLUSIONS

In this first population-level examination of the determinants of home discharge among survivors of NF, older age, Medicare insurance, selected comorbidities, and development of organ failure decreased patients' odds of home discharge. Unexpectedly, male gender, Hispanic ethnicity, lack of health insurance, and being managed at a teaching hospital were associated with favorable impact on patients' discharge disposition. Further studies are warranted in other populations and healthcare environments to corroborate the present findings and to refine our understanding of the factors affecting short-term outcomes among NF survivors.

The Prediction Predicament: Rethinking Necrotizing Soft Tissue Infections Mortality

BACKGROUND

Our study sought to identify independent risk factors predisposing patients with necrotizing soft tissue infections (NSTIs) to mortality from among laboratory values, demographic data, and microbiologic findings in a small population. To this end, a retrospective review was conducted of the medical records of all patients with NSTI who had been treated at our institution from 2003 to 2012 (n=134).

METHODS

Baseline demographics and comorbidities, clinical and laboratory values, hospital course, and the microbiologic characteristics of surgical incision cultures were recorded. Each variable was tested for association with survival status and all associated variables with p<0.15 were included in a logistic regression model to seek factors associated independently with mortality.

RESULTS

Surprisingly, no demographic or pre-existing condition proved to be a predictor of mortality. Two laboratory values had an inverse correlation to mortality: High C-reactive protein (CRP) and highest recorded CRP. Of surgical incisions that grew bacteria in culture, 33.6% were polymicrobial. Mortality rates were highest with Enterococcus-containing polymicrobial infections (50%), followed by those containing Pseudomonas (40%), and Streptococcus spp. (27%). Understanding why so many studies across the literature, now including our own, find such disparate results for correlation of NSTI mortality with patient data may lie in the fundamentally dynamic nature of the organisms involved.

CONCLUSIONS

This study suggests that no single factor present on admission is a robust predictor of outcome; it is likely that survival in NSTI is predicated upon a complex interaction of multiple host and microbial factors that do not lend themselves to reduction into a simple formula. It is also abundantly clear that the well-established principles of NSTI surgery should continue to be followed in all cases, with an emphasis on early debridement, irrespective of apparent severity of initial presentation.