Risk factors for mortality in the late amputation of necrotizing fasciitis: a retrospective study

Machine Learning Approach to Classify Vibrio vulnificus Necrotizing Fasciitis, Non-Vibrio Necrotizing Fasciitis and Cellulitis

Background

Recent advancements in artificial intelligence have led to increased adoption of machine learning in disease identification, particularly for challenging diagnoses like necrotizing fasciitis and Vibrio vulnificus infections. This shift is driven by the technology's efficiency, objectivity, and accuracy, offering potential solutions to longstanding diagnostic hurdles in clinical practice.

Methods

This investigation incorporated 180 inpatients suffering from soft tissue infections. The participants were categorized into groups: cellulitis, non-Vibrio necrotizing fasciitis (NF), or V. Vulnificus NF. To predict the three relevant outcomes, we employed Light Gradient Boosting Machine (LightGBM) and 5-fold cross-validation methodologies for the development of a multi-class categorization model. Moreover, we applied the SHapley Additive exPlanations (SHAP) methodology to decipher the model's predictions.

Results

The multi-classification model possesses substantial predictive capacity, with a weighted-average AUC of 0.86, sensitivity of 87.2%, specificity of 74.5%, NPV of 81.6%, and PPV of 85.4%. The model's calibration was assessed using the Brier score, yielding a weighted mean of 0.084. This low value demonstrates a strong correlation between predicted probabilities and actual outcomes, indicating high predictive accuracy and reliability in the model's forecasts.

Conclusions

We effectively developed a multiclassification model aimed at forecasting the occurrence of cellulitis, non-Vibrio NF, or V. Vulnificus NF in patients suffering from soft tissue infection, and we further described the model's predictions using the SHAP algorithm.

Socioeconomic status affects amputation and mortality rates in necrotizing fasciitis patients

PURPOSE

Necrotizing fasciitis (NF) is a rare, but rapidly progressing bacterial infection of the subcutaneous tissues and muscular fascia with high rates of morbidity and mortality. Our study aims to determine if socioeconomic status (SES) is a predictor of outcomes in NF.

METHODS

A retrospective review was conducted of patients diagnosed with NF at our institution. Demographic information, insurance status, medical and surgical history, vitals, ASA score, blood laboratory values, surgical procedure information, and outcomes prior to patient discharge were collected. Patient zip codes were utilized to obtain median household incomes at the time of the patient's surgical procedure to determine SES. Patients without complete data in their medical record were excluded. Initial descriptive statistics and logistic regression models were performed.

RESULTS

We identified 196 patients (mean age 50.13 ± 13.03 years, 31.6% female) for inclusion. Mortality rate was 15.3% (n = 30) and 33.7% (n = 66) underwent amputation. Mortality rate was not significantly different across income brackets. Lower income brackets had higher rates of amputation than higher income brackets (p < 0.05). A logistic regression models showed the rate of amputation decreases by 29% for every $10,000 increment in median household income and ASA score decreased by 0.15 units for every $10,000 increase in median household income.

CONCLUSIONS

Amputation rates in cases of NF are significantly higher in lower SES groups than higher SES groups. Patients with perivascular disease in lower SES groups were more likely to experience serious complications of NF than their counterparts in higher SES groups.

Acute Limb Ischemia Management and Complications: From Catheter-Directed Thrombolysis to Long-Term Follow-up

Acute limb ischemia (ALI) is a vascular emergency that needs to be diagnosed and treated quickly to prevent permanent tissue damage and amputation. Catheter-directed thrombolysis is a possible treatment option for mild to moderate ALI, with improved results from endovascular procedures and thrombolytic drugs. However, patients receiving thrombolysis may experience higher rates of distal embolization, serious bleeding events, and stroke than those undergoing surgery. The review article emphasizes the need for postoperative and extended management of ALI patients, including monitoring for compartment syndrome, managing reperfusion damage, and reducing changeable cardiovascular risk factors such as lipid-lowering therapy, diabetes management, and smoking cessation. Complications that can arise from thrombolytic therapy are also discussed, including hemorrhagic complications, minor bleeding, and reperfusion damage, with recommendations to monitor patients closely during treatment and discontinue therapy immediately if any abnormalities are detected. Follow-up evaluations for patients, including Doppler ultrasound, ankle brachial index, pulse volume recordings, and laboratory tests, are recommended to ensure the best possible outcome for patients with ALI.

Can The Systemic Immune-Inflammation Index (SII) and Charlson Comorbidity Index (CCI) be used to predict mortality in patients with necrotizing fasciitis?

PURPOSE

This study aimed to determine the impact of mortality and morbidity indices on the diagnosis and prognosis of patients suffering from necrotizing fasciitis.

METHODS

A retrospective analysis was performed on 41 patients (26 females, 15 males) with necrotizing fasciitis (NF). The SII (Systemic Immune-Inflammation Index) was computed using the formula SII = (P × N)/L, where P, N, and L measure the counts of peripheral platelets, neutrophils, and lymphocytes, respectively. This study evaluated the clinicopathological characteristics and follow-up information to assess the comparative effectiveness of SII, CCI (Charlson Comorbidity Index), and LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) scores as mortality and morbidity indices for patients with NF.

RESULTS

The optimal cut-off for SII was determined to be 455. The SII value in the group with mortality was significantly higher compared to the group without mortality (p < 0.05). The CCI value in the group with mortality was significantly higher than the group without mortality (p < 0.05). The SII and CCI values were found to be effective in distinguishing between patients who suffered mortality and those who did not.

CONCLUSION

SII is a powerful tool for predicting mortality in patients with necrotizing fasciitis (NF). The SII index provides a novel, easily accessible, and inexpensive indicator for monitoring the progress and predicting the survival of patients with NF.

Association between time to surgery and hospital mortality in patients with community-acquired limb necrotizing fasciitis: an 11-year multicenter retrospective cohort analysis

BACKGROUND

Necrotizing fasciitis (NF) is a rare but potentially life-threatening soft tissue infection. The objective of this study was to assess the association between timely surgery within 6 h and hospital mortality in patients with limb NF, and to describe the trends in patients with NF, time to surgery and standardized mortality ratio (SMR) over 11 years.

METHODS

This was a multicenter, retrospective cohort study of all intensive care unit patients who had emergency surgery within 24 h of hospitalization for limb NF between April 1, 2008 and March 31, 2019 in Hong Kong. Timely surgery was defined as the first surgical treatment within 6 h of initial hospitalization. Appropriate antibiotics were achieved if the patient was given antibiotic(s) for all documented pathogens prior to or on day of culture results. The primary outcome was hospital mortality.

RESULTS

There were 495 patients (median age 62 years, 349 (70.5%) males) with limb NF treated by surgery within 24 h of hospitalization over the 11 years. Appropriate antibiotic(s) were used in 392 (79.2%) patients. There were 181 (36.5%) deaths. Timely surgery was not associated with hospital mortality (Relative Risk 0.89, 95% CI: 0.73 to 1.07) but admission year, advanced age, higher severity of illness, comorbidities, renal replacement therapy, vasopressor use, and type of surgery were significant predictors in the multivariable model. There was an upward trend in NF diagnosis (1.9 cases/year, 95% CI: 0.7 to 3.1; P < 0.01; R2 = 0.60) but there was no downward trend in median time to surgery (-0.2 h/year, 95% CI: -0.4 to 0.1; P = 0.16) or SMR (-0.02/year, 95% CI: -0.06 to 0.01; P = 0.22; R2 = 0.16).

CONCLUSIONS

Among patients operated within 24 h, very early surgery within 6-12 h was not associated with survival. Increasing limb NF cases were reported each year but mortality remained high despite a high rate of appropriate antibiotic use and timely surgical intervention.

Risk Factors for Predicting Mortality and Amputation of Patients with Necrotizing Soft-Tissue Infections: Retrospective Analysis of 111 Cases from a Single Medical Center

Objective

Necrotizing soft-tissue infections (NSTIs) are rare clinical infections with surgical emergencies having a high mortality rate. This study aimed to investigate risk factors for mortality and amputation of patients with NSTI.

Methods

We retrospectively analyzed critical factors for outcomes of 111 patients with NSTI hospitalized in our department from 1 January 1999 to 31 December 2018. NSTI diagnosis was based on the patient's clinical characteristics, laboratory risk indicator for necrotizing fasciitis (LRINEC) score, laboratory test data, and microbiological findings in blood and wound culture. The risk factors for mortality and amputation of NSTI were determined using univariate or multivariate logistic regression analysis, receiver operating characteristics (ROC), and the area under the ROC curve (AUC) at 90 days after admission.

Results

Diagnosis of 111 patients with NSTI was confirmed according to clinical features, LRINEC score, image data, laboratory findings, and microorganism culture in blood and wounds. The mortality rate was 9.91% (11/111) at day 90 follow-up. High white blood cell (WBC), low hematocrit (HCT), and multiple surgeries were identified to be critical risk factors for NSTI mortality in univariate and multivariate logistic analyses. AUCs, 95% confidence intervals (CI), and P values of risk factors were 0.699, 0.54-0.95, and P = 0.0117 for high WBC; 0.788, 0.63-0.97, and P = 0.0006 for low HCT; and 0.745, 0.59-0.90, and P = 0.0018 for multiple surgeries, respectively. These patients also had high LRINEC scores. Amputation occurred in 34.23% (38/111) of patients. Risk factors for amputation were higher age, low hemoglobin (Hb), and multiple wounds. AUCs, 95% confidence intervals (CI), and P values were 0.713, 0.11-0.32, and P < 0.0001 for higher age; 0.798, 0.08-0.29, and P=0.0007 for low Hb; and 0.757, 0.17-0.34, and P  < 0.0001 for multiple lesion sites, respectively.

Conclusions

High LRINEC scores, high WBC, low HCT, and multiple surgeries were relevant to increased mortality. Higher age, low Hb, and multiple wounds were associated with amputation risk. These clinical features must be paid attention to when patients are diagnosed with NSTI.

Initial skin necrosis presentation at emergency room was associated with fulminant clinical course and mortality in patients with Vibrio necrotizing fasciitis

Necrotizing fasciitis (NF) is a life-threatening infection. Skin necrosis is an important skin sign of NF. The purposes of this study was to investigate the initial skin conditions of Vibrio NF patients between emergency room (ER) to preoperative status, to compare the clinical and laboratory risk indicators of the skin necrosis group and non-skin necrosis group when they arrived at ER, and to evaluate whether initial cutaneous necrosis related to fulminant course and higher fatalities. From 2015 to 2019, seventy-two Vibrio NF patients with surgical confirmation were enrolled. We identified 25 patients for inclusion in the skin necrosis group and 47 patients for inclusion in the non-skin necrosis group due to the appearance of skin lesion at ER. Seven patients died, resulting in a mortality rate of 9.7%. Six patients of skin necrosis group and one patient of non-skin necrosis group died, which revealed the skin necrosis group had a significantly higher mortality rate than the non-skin necrosis group. All the patients in the skin necrosis group and 30 patients of non-skin necrosis group developed serous or hemorrhagic bullous lesions before operation (p = 0.0003). The skin necrosis group had a significantly higher incidence of APACHE score, postoperative intubation, Intensive care unit stay, septic shock, leukopenia, higher counts of banded leukocytes, elevated C-reactive protein (CRP), and lower serum albumin level. Vibrio NF patients presenting skin necrosis at ER were significantly associated with fulminant clinical courses and higher mortality. Physicians should alert the appearance of skin necrosis at ER to early suspect NF and treat aggressively by those clinical and laboratory risk indicators, such as elevated APACHE score, shock, leukopenia, higher banded leukocytes, elevated CRP, and hypoalbuminia.

Necrotizing fasciitis of the extremities in high and low Charlson Comorbidity Index: A multi-center retrospective cohort study

BACKGROUND

Necrotizing fasciitis (NF) is a life-threatening and acute progressive soft tissue infection and needs early surgical intervention, that is, debridement or amputation. Surgical strategy or prognosis is influenced by the speed of progression and patients' general condition, which can be calculated by the Charlson Comorbidity Index (CCI). The purpose of this study was to investigate the association between the CCI scores and prognosis of patients with NF of the upper/lower extremities.

METHODS

In the retrospective cohort study, we analyzed patients with NF of the upper/lower extremities who were determined to undergo surgery by orthopedic surgeons at four tertiary hospitals between August 2003 and April 2016. We divided the patients into two groups, Group L (low CCI scores of 0-2) and Group H (high CCI scores of ≥3). The primary event of this study was defined as death or amputation. Mortality cases were included when amputation was informed with documented certification but patients died while waiting for surgery. We compared the patients' background, laboratory data on admission, the laboratory risk indicator for necrotizing fasciitis (LRINEC) score, and primary outcome between the two groups.

RESULTS

Of the 56 patients, 28 patients were classified into Group L and the other 28 patients into Group H. The data in this study showed that patients in Group H had lower white blood cell counts and hemoglobin and higher creatinine than Group L, but there was no difference in LRINEC scores between the two groups. Streptococcus pyogenes was the most common infectious agent in Group L (54%) but not in Group H (11%). Poorer outcome was observed in Group H compared with Group L (4 mortality and 16 amputation vs. no mortality and 9 amputation, P = 0.007).

CONCLUSIONS

Laboratory data and causative microorganisms were different between high CCI and low CCI patients with NF. High CCI scores were associated with limb amputation or death caused by NF of the upper/lower extremities; whereas, low CCI scores were more likely associated with S. pyogenes monoinfection.

Use of Clindamycin for Necrotizing Soft Tissue Infection Decreases Amputation Rate

OBJECTIVE

To identify the impact of clindamycin use on mortality and amputation rates in patients with necrotizing fasciitis.

DESIGN

Retrospective review.

SETTING

Level 1 trauma center, single-center study.

PATIENTS/PARTICIPANTS

All patients from 2008 to 2019 with a diagnosis of necrotizing fasciitis. One hundred ninety patients were included in statistical analysis.

INTERVENTION

Use of clindamycin in the initial antibiotic regimen in the treatment of necrotizing soft tissue infection.

MAIN OUTCOME MEASUREMENTS

Amputation and mortality rates.

RESULTS

Patients who received clindamycin had 2.92 times reduced odds of having an amputation when compared with their counterparts, even when American Society of Anesthesiologist scores, comorbidities, smoking, drug use, alcohol consumption, race, ethnicity, sex, and age were controlled for and regardless of other antibiotics started (P = 0.015). There was no significant difference in mortality rate between those patients who did and did not receive clindamycin as part of their initial antibiotic regimen (8.3% vs. 11.6%, respectively; P = 0.453).

CONCLUSION

The use of clindamycin in the initial antibiotic regimen for treatment of NSTI was shown to significantly decrease rates of amputation but not mortality.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Early Diagnosis and Surgical Management of Necrotizing Fasciitis of the Lower Extremities: Risk Factors for Mortality and Amputation

Objective: In this study, we seek to identify patient characteristics associated with limb loss and mortality while exploring the potential impact a multidisciplinary care team may have. Approach: This was a 10-year retrospective review of patients presenting to our tertiary care center for limb salvage with a diagnosis of lower extremity (LE) necrotizing fasciitis (NF). Patient demographics, clinical history, and outcomes were compared between survivors and nonsurvivors and between those who underwent LE amputation and those who did not. The article adheres to the strengthening the reporting of observational studies in epidemiology statement. Results: Sixty-two patients presented to our tertiary care center for limb salvage with LE NF. Forty-two patients underwent LE amputation: 27 (43.5%) underwent below-knee amputation, 1 (1.6%) underwent above-knee amputation, 8 (12.9%) underwent transmetatarsal amputation and 2 (3.2%) underwent calcanectomy. The overall mortality rate was 16.1% (n = 10). Risk factors for mortality included increased age (p = 0.034), higher Charlson Comorbidity Index (p = 0.011), thrombocytopenia (p = 0.002), hypotension (p = 0.015), erythema (p = 0.010), pain (p = 0.027), diabetes mellitus (p = 0.012), and malignancy (p < 0.001). Risk factors for LE amputation included DM (p = 0.017), peripheral vascular disease (p = 0.033), and an elevated laboratory risk indicator for necrotizing fasciitis (LRINC) (p = 0.033). Innovation: To identify outcomes after admission to a tertiary hospital with a dedicated limb salvage team with LE NF and to analyze risk factors for mortality and amputation. Conclusions: This is a comprehensive analysis of risk factors for mortality and amputation after LE NF. Our institution's experience highlights the importance of a multidisciplinary approach in the care of these patients.

Distribution and drug sensitivity of pathogenic bacteria in diabetic foot ulcer patients with necrotizing fasciitis at a diabetic foot center in China

Background

Diabetic foot ulcer is one of the major complications for patients with diabetes, and has become an important cause of non-traumatic amputation. Necrotizing fasciitis is a life-threatening soft-tissue infection involving the fascia and subcutaneous tissue. When diabetic foot ulcers are complicated by necrotizing fasciitis (DNF), this increases the risk for amputation and mortality, making DNF treatment more complicated, and eventually leading to amputation and mortality. However, studies on pathogenic bacteria’s distribution and drug sensitivity in DNF patients remain lacking. This study investigated the distribution and susceptibility of pathogenic bacteria in DNF patients, and provided empirical antibacterial guidance for the clinic.

Methods

In a single diabetic foot center, the results from microbial cultures and drug susceptibility tests of patients with DNF from October 2013 to December 2020 were collected and analyzed.

Results

A total of 101 DNF patients were included in this study, of whom 94 had positive culture test results. A total of 124 pathogens were cultured, including 76 Gram-positive bacterial strains, 42 Gram-negative bacterial strains, and six fungal strains. Polymicrobial infections accounted for 26.7% and monomicrobial infections accounted for 66.3%. Staphylococcus aureus was the most common bacterium isolated, followed by Enterococcus faecalis and Streptococcus agalactiae. Pseudomonas aeruginosa, Klebsiella pneumoniae, and Proteus mirabilis were the most common Gram-negative bacteria. Thirty-five strains of multi-drug resistant bacteria were isolated, representing 28.2% of the total isolates. Gram-positive bacteria were more sensitive to levofloxacin, moxifloxacin, vancomycin, teicoplanin, tigecycline, and linezolid, while Gram-negative bacteria were more sensitive to amikacin, piperacillin/tazobactam, cefoperazone/sulbactam, ceftazidime, cefepime, imipenem, and meropenem.

Conclusions

Gram-positive bacteria were the main bacteria isolated from DNF patients. The bacterial composition, the proportion of multi-drug resistant bacteria among the pathogens, and the high risk for amputation should be fully considered in the initial empirical medication, and broad-spectrum antibacterials are recommended.

[Two cases of Vibrio vulnificus primary sepsis]

This article analyzed the medical records of two patients with Vibrio vulnificus primary sepsis who were admitted to the First Affiliated Hospital of Naval Medical University and reviewed the latest literature. On November 6, 2019, a 54-year-old male patient was admitted to the hospital. The patient's lower limbs were red, swollen, and painful with ecchymosis and hemorrhagic bullae after he ate freshwater products. The emergency fasciotomy was performed 3 h after admission, and the multiple organ failure occurred after operation. The patient was given up treatment 24 h after admission. On August 12, 2020, a 73-year-old male patient was admitted to the hospital. He was in shock state on admission and had hemorrhagic bullae on his right lower limb after he ate seafood. At 3 h post admission, he underwent emergency surgical exploration and amputation of right thigh. Six days later, he received negative pressure wound treatment on the stump. On the 13th day post admission, his families forgo the active treatment and he died 15 d after admission. The two cases were both failed to be diagnosed at the first time, and the disease progressed rapidly. Necrotizing fasciitis and multiple organ failure occurred. After the diagnosis was confirmed, timely fasciotomy and high amputation were performed respectively. The microbiological examinations both reported Vibrio vulnificus. Although the 2 cases were not cured successfully, the course of disease and some indexes of patient with early amputation were better than those of patients with fasciotomy. Vibrio vulnificus is widely distributed and frequently detected in fresh water products. The pathogenic pathway is fuzzy and complex, and it is easy to be misdiagnosed. It is necessary to establish the treatment process of Vibrio vulnificus sepsis. Early and aggressive surgical intervention should be carried out as soon as possible, fasciotomy and debridement should be thorough, and the patients with hemorrhagic bullae should be amputated early. Postoperative comprehensive measures are also important for improving the survival rate of patients.

A Systematic Review and Meta-Analysis of the Effectiveness of LRINEC Score for Predicting Upper and Lower Extremity Necrotizing Fasciitis

This review and meta-analysis aims to assess the prognostic value of the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score for detecting necrotizing fasciitis in the extremities. The LRINEC score has been validated in multiple studies as a clinical tool for differentiating necrotizing fasciitis from non-necrotizing infections however many studies do not specify the location of infection. As the prevalence of diabetes and diabetic foot infections continues to rise, the utility of LRINEC scores in these populations becomes of increased importance. Four databases were reviewed for citations between January 2010 and December 2020. English, full text articles reporting the diagnostic effects of LRINEC were utilized in the systematic review portion of this paper. Further inclusion of 2 × 2 tables and discussion specific to the extremities were applied for citations implemented in the meta-analysis. Of the 111 results, 12 citations (n = 932) were included in this review. The diagnostic sensitivity of the LRINEC score ranged from 36% to 77% while specificity ranged from 72% to 93%. Cumulative odds ratio for LRINEC ≥6 among the 4 studies assessing extremity necrotizing fasciitis was 4.3 with p value of <.05. Sensitivity, specificity, positive predictive value, and negative predictive value was 49.39%, 83.17%, 34.91%, and 89.99%, respectively. Accuracy, the classification by whether a patient was correctly classified, was 77.95%. LRINEC score is effective at distinguishing necrotizing fasciitis from other soft tissue infections however the LRINEC's score greatest clinical application may be its ability to rule out necrotizing fasciitis while its ability to accurately identify the presence of infection remains suboptimal.

Comparison of Surgical Outcomes and Predictors in Patients with Monomicrobial Necrotizing Fasciitis and Sepsis Caused by Vibrio vulnificus, Aeromonas hydrophila, and Aeromonas sobria

Background: Monomicrobial necrotizing fasciitis caused by Vibrio vulnificus, Aeromonas hydrophila, and Aeromonas sobria are often associated with high mortality rates. The purpose of this study was to compare the independent predictors related to outcomes between Vibrio vulnificus and Aeromonas species necrotizing fasciitis. Patients and Methods: Monomicrobial necrotizing fasciitis caused by Vibrio vulnificus (60 patients) and Aeromonas species (31 patients) over an 11-year period were reviewed retrospectively. Differences in mortality, patient characteristics, clinical presentations, and laboratory data were compared between the Vibrio vulnificus and Aeromonas species groups, and between the death and the survival subgroups of patients with Aeromonas species. Results: Six patients in the Vibrio vulnificus group (10%) and 11 in the Aeromonas species group (32.3%) died. Fifty-nine patents had bacteremia and 16 patients died (27.1%). Patients who had Vibrio vulnificus had a higher incidence of bacteremia. The patients who had Aeromonas species presenting with bacteremia were significantly associated with death. The death subgroup of patients with Aeromonas necrotizing fasciitis had a higher incidence of bacteremia, higher counts of banded leukocytes, lower platelet counts, lower total lymphocyte counts, and lower serum albumin level than the survival subgroup. Conclusions: Monomicrobial necrotizing fasciitis caused by Aeromonas species was characterized by more fulminating and higher mortality than that of Vibrio vulnificus, even after early fasciotomy and third-generation cephalosporin antibiotic therapy. Those risk factors, such as bacteremia, shock, lower platelet counts, lower albumin levels, and antibiotic resistance were associated with mortality, which should alert clinicians to pay more attention to and aggressively treat those patients with Aeromonas and Vibrio necrotizing fasciitis.

Novel Clinical Risk Scoring Model for Predicting Amputation in Patients With Necrotizing Fasciitis: The ANF Risk Scoring System

Background: Necrotizing fasciitis (NF) is a life-threatening infection of the skin and soft tissue that spreads quickly and requires immediate surgery and medical treatment. Amputation or radical debridement of necrotic tissue is generally always required. The risks and benefits of both the surgical options are weighed before deciding whether to amputate or debride. This study set forth to create an easy-to-use risk scoring system for predicting the risk scoring system for amputation in patients with NF (ANF).

Methods: This retrospective study included 1,506 patients diagnosed with surgically confirmed NF at three general hospitals in Thailand from January 2009 to December 2012. All diagnoses were made by surgeons who strictly observed the guidelines for skin and soft tissue infections produced by the Infectious Diseases Society of America. Patients were randomly allocated to either the derivation (n = 1,193) or validation (n = 313) cohort. Clinical risk factors assessed at the time of recruitment were used to create the risk score, which was then developed using logistic regression. The regression coefficients were converted into item scores, and the total score was calculated.

Results: The following four clinical predictors were used to create the model: female gender, diabetes mellitus, wound appearance stage 3 (skin necrosis and gangrene), and creatinine ≥1.6 mg/dL. Using the area under the receiver operating characteristic curve (AuROC), the ANF system showed moderate power (78.68%) to predict amputation in patients with NF with excellent calibration (Hosmer-Lemeshow χ² = 2.59; p = 0.8586). The positive likelihood ratio of amputation in low-risk (score ≤ 4) and high-risk (score ≥ 7) patients was 2.17 (95%CI: 1.66–2.82) and 6.18 (95%CI: 4.08–9.36), respectively. The ANF system showed good performance (AuROC 76.82%) when applied in the validation cohort.

Conclusion: The developed ANF risk scoring system, which includes four easy to obtain predictors, provides physicians with prediction indices for amputation in patients with NF. This model will assist clinicians with surgical decision-making in this time-sensitive clinical setting.

Utility of the Lactate/Albumin Ratio as a Predictor for Mortality in Necrotizing Fasciitis Patients

Background

The lactate/albumin (L/A) ratio has been proposed as a prognostic marker because the ratio is associated with multiple organ failure and mortality in critically ill patients. We aimed to investigate the clinical utility of the L/A ratio as a good prognostic indicator of mortality in a cohort of necrotizing fasciitis patients.

Method

This retrospective study was conducted in two tertiary hospitals in Taiwan between 2015 and 2020. We reviewed adult patients with measured serum lactate and albumin on the emergency department (ED) arrival to evaluate the prognostic performance of the lactate and lactate/albumin (L/A) ratio for outcome prediction.

Result

Of the 262 NF patients, 20 (7.63%) died in the hospital. The area under the receiver operating characteristic curve (AUROC) value of the L/A ratio (0.76, 95% confidence interval [CI] 0.69–0.81, P < 0.01) was higher than lactate alone (0.71, 95% CI 0.65–0.74 P < 0.01) for predicting in-hospital mortality. The optimal cutoff of the L/A ratio was 1.61. The AUROC value of the L/A ratio was better than lactate alone regardless of normal lactate level. The cutoff of L/A ratio and hypoalbuminemia showed further discriminative value for in-hospital mortality even in patients with normal lactate levels.

Conclusion

The prognostic performance of the L/A ratio was superior to a single measurement of lactate for predicting in-hospital mortality and intensive care unit (ICU) lengths in necrotizing fasciitis patients. Aggressive intervention and intensive care were necessary for high-risk NF patients upon ED arrival.

Utility of modified Laboratory Risk Indicator for Necrotizing Fasciitis (MLRINEC) score in distinguishing necrotizing from non-necrotizing soft tissue infections

Background

We conducted this study to promote a modified Laboratory Risk Indicator for Necrotizing Fasciitis (MLRINEC) score and evaluate the utility in distinguishing necrotizing fasciitis (NF) from other soft-tissue infections.

Method

A retrospective cohort study of hospitalized patients with NF diagnosed by surgical finding was conducted in two tertiary hospital in southern Taiwan between January 2015 and January 2020. Another group was matched by controls with non-necrotizing soft tissue infections based on time, demographics, and immune status. Data such as infectious location, comorbidities, and laboratory findings were recorded and compared. Logistics regression were used to determine the association with NF after adjustment for confounders and MLRINEC score was developed by then. Receiver operating curve (ROC) and the area under the curve (AUC) were used to evaluate its discriminating ability.

Result

A total of 303 patients were included; 101 in NF group and 202 in non-NF group. We added serum lactate and comorbid liver disease to the original LRINEC score and re-defined the cut-off values for 3 variables to develop the MLRINEC score. The cut-off value for MLRINEC score was 12 points with corresponding sensitivity of 91.8% and a specificity of 88.4%, and the area under ROC (AUC) was 0.893 (95% CI, 0.723 to 0.948; p < 0.01).

Conclusion

MLRINEC score shows a high sensitivity and specificity in distinguishing NF from non-necrotizing soft-tissue infections. Patients with a MLRINEC score > 12 points should be highly suspected of presence of necrotizing fasciitis.

Necrotizing Soft Tissue Infections in Intensive Care

Background:

Necrotizing soft tissue infections (NSTIs) are typically characterized by extensive soft tissue destruction with systemic signs of toxicity, ranging from sepsis to septic shock. Our aim was to analyze the clinical characteristics, microbiological results, laboratory data, therapies, and outcome of patients with NSTIs admitted to an intensive care unit (ICU).

Methods:

A monocentric observational study of patients admitted to the ICU of a university hospital between January 2009 and December 2017. The demographic characteristics, comorbidities, clinical features, microbiology and laboratory results, organ dysfunctions, therapies, and outcome were retrospectively analyzed.

Results:

There were 59 patients and 70% males. The mean age (± SD) was 55 ± 18; type II (monomicrobial) NSTI was present in 36 patients (61%); the most common isolated pathogen was Streptococcus pyogenes in 28 patients (48%). Septic shock was diagnosed in 41 patients (70%). The most common organ dysfunctions were circulatory and renal in 42 (71%) and 38 patients (64%). The mean value (± SD) of serum lactate at admission to the ICU was 4.22 ± 5.42 mmol/l, the median SOFA score and SAPS II were 7 (IQR 4 - 10) and 46 (IQR 30.5 - 53). ICU mortality rate was 25%. Both SOFA score and serum lactate demonstrated a good prognostic value regarding ICU outcome (OR 1.29, 95%CI 1.07-1.57, P < 0.007 and OR 1.53, 95%CI 1.19-1.98, P < 0.001). A cut-off value for serum lactate of 6.55 mmol/L positively predicted mortality with 67% sensitivity and 97% specificity.

Conclusion:

NSTIs carry a high risk of septic shock and multiple organ dysfunction syndrome and thus are still associated with high mortality. In our study, the value of serum lactate at admission to the ICU correlated well with mortality. This easy-to-measure parameter could play a role in the decision-making process regarding prognosis and continuation of care.

Surgical Infection Society 2020 Updated Guidelines on the Management of Complicated Skin and Soft Tissue Infections

Background: The Surgical Infection Society (SIS) Guidelines for the treatment of complicated skin and soft tissue infections (SSTIs) were published in October 2009 in Surgical Infections. The purpose of this project was to provide a succinct update on the earlier guidelines based on an additional decade of data. Methods: We reviewed the previous guidelines eliminating bite wounds and diabetic foot infections including their associated references. Relevant articles on the topic of complicated SSTIs from 2008-2020 were reviewed and graded individually. Comparisons were then made between the old and the new graded recommendations with review of the older references by two authors when there was disparity between the grades. Results: The majority of new studies addressed antimicrobial options and duration of therapy particularly in complicated abscesses. There were fewer updated studies on diagnosis and specific operative interventions. Many of the topics addressed in the original guidelines had no new literature to evaluate. Conclusions: Most recommendations remain unchanged from the original guidelines with the exception of increased support for adjuvant antimicrobial therapy after drainage of complex abscess and increased data for the use of alternative antimicrobial agents.

Necrotizing fasciitis, causative agents and management: a five-year retrospective study in two tertiary care hospitals in Central Malaysia

PURPOSE

Necrotizing fasciitis (NF) is a rapidly progressive inflammatory infection of the fascia, with secondary necrosis of the subcutaneous tissues. The severity of the disease depends on the virulence of the organism and host immunity. There is a paucity of reports on the prevalence of NF causing pathogens and management.

METHODS

Retrospective data of patients treated for NF were collected from two tertiary care hospitals in Central Malaysia between January 2014 and December 2018.

RESULTS

A total of 469 NF patients were identified. More than half of the NF patients were males (n = 278; 59.28%). The highest number of cases was found among age groups between 30 and 79, with mean age of 56.17. The majority of the NF cases (n = 402; 85.72%) were monomicrobial. Streptococcus spp. (n = 89; 18.98%), Pseudomonas aeruginosa (n = 63; 13.44%) and Staphylococcus spp. (n = 61; 13.01%) were identified as the top three microorganisms isolated. Among the 469 NF cases, 173 (36.8%) were amputated or dead while 296 (63.1%) recovered. Proteus spp. (n = 19; 12.93%), Klebsiella pneumoniae (n = 18; 12.24%) and Escherichia coli (n = 14; 9.52%) were associated with all types of amputations. The most common antibiotic prescribed was unasyn (n = 284; 60.56%), followed by clindamycin (n = 56; 11.94%) and ceftazidime (n = 41; 8.74%). A total of 239 (61.8%) recovered while 148 (38.2%) were either amputated or dead when managed with the unasyn, clindamycin or ceftazidime.

CONCLUSION

This study represents the largest NF cases series in Malaysia highlighting the causative agents and management.

Reconstruction of Lower Limb Necrotizing Fasciitis by Hydrosurgical Debridement and Multiperforator Anterolateral Thigh Flap

The authors describe a surgical treatment that optimally combined the use of the hydrosurgical system and a free multiperforator anterolateral thigh flap to prevent lower limb amputation in a severe case of necrotizing fasciitis. A 43-year-old woman was diagnosed with necrotizing fasciitis, and amputation was performed at the level of the metatarsal shafts with an emergency debridement using the hydrosurgical system. In the second reconstructive surgery, a free anterolateral thigh flap measuring 28 × 8 cm² was harvested using the left thigh as the donor site and the vascular pedicle was made up of a total of 3 vessels, 2 perforating arteries from the descending branch of the lateral circumflex femoral artery, and 1 oblique branch from the lateral circumflex femoral artery. To thin the flap, we first resected as much subcutaneous fat as possible in the distal part of the flap (which would eventually cover the ankle joint) and ensured adequate residual volume of the proximal part of the flap (which would cover the metatarsal stumps). We then sutured the flap to the tissue defect on the left foot and then end-to-side anastomosing the lateral femoral circumflex artery and posterior tibial artery while the 2 veins were anastomosed to the posterior tibial veins under a microscope. Six months after the surgery, adequate flap volume was maintained over the metatarsal stumps with no postoperative complications such as infection or ulcer formation, and there were no other complications such as motor dysfunction at the donor site on the left thigh.

Necrotizing Soft Tissue Infections of the Upper Extremity

Necrotizing soft tissue infections of the upper extremity have varying microbiologies and etiologies. Risk factors for development include diabetes mellitus, intravenous drug use, peripheral arterial disease, smoking, alcohol abuse, and immunocompromised state. Although clinical examination is the mainstay of diagnosis, laboratory tests and imaging can aid in diagnosis. Surgical débridements usually are needed for treatment, with resultant defects that often require reconstruction. Rates of amputation are reported as 22% to 37.5% and mortality from necrotizing soft tissue infections of the upper extremity from 22% to 34%. Prompt surgical and antimicrobial treatment is necessary to decrease risk of loss of limb or life.

Mortality Risk in Necrotizing Fasciitis: National Prevalence, Trend, and Burden

Background: Necrotizing fasciitis (NF) is a fulminant, life-threating infection of fascia and subcutaneous tissue. Because of the low incidence, previous studies were statistically underpowered to assess factors associated with the risk of mortality. The aim of this study is to identify the risk factors associated with mortality in this select group of patients. Methods: A retrospective cross-sectional study was performed utilizing the Nationwide Readmissions Database, 2010-2014. The database captures 56.6% of all U.S. annual hospitalizations. Study population included inpatients admitted emergently with NF. Results: A total of 4,178 cases were included, of which 2,061(48.9%) patients had a history of diabetes mellitus (DM). The most common presentation was septicemia (39.5%) and 9.2% were admitted initially as cellulitis/abscess. Overall mortality risk was 12.6% with no substantial change in the annual trend. Mortality in patients with diabetes was substantially lower (8.5% vs. 16.5%, odds ratio [OR]: 0.44, 95% confidence interval [CI] = [0.34, 0.56], p < 0.001). Factors associated with a higher mortality risk included: older age, chronic liver diseases, disseminated intravascular coagulopathy, septic shock, pulmonary complications, acute renal failure, and not undergoing surgical intervention (p < 0.05 each). Patients who did not undergo surgical debridement were more likely to be ≥65 years of age and have multiple comorbidities. Hyperbaric oxygen therapy and intravenous immunoglobulin were used in 1.3% and 0.3% of the sample, respectively, with no reported use among patients who died. Conclusions: This study provides a new and updated perspective on the prevalence, trend, and outcomes of NF in the United States. Necrotizing fasciitis is associated with septicemia and lack of surgical intervention is associated with a higher mortality.

Lactate on emergency department arrival as a predictor of in-hospital mortality in necrotizing fasciitis: a retrospective study

Background

Hyperlactatemia is known to be associated with adverse outcome in critical illness. In this study, we attempted to identify if hyperlactatemia on emergency department (ED) arrival is a reliable predictor for in-hospital mortality in necrotizing fasciitis (NF) patients.

Method

A prospective cohort study of hospitalized patients with NF was conducted in two tertiary teaching hospitals in Taiwan between March 2010 and March 2018. Blood samples were collected in the ED upon arrival, and the lactate levels were determined. Sequential organ failure assessment (SOFA) scores were calculated during the first 24 h after admission. All collected data were statistically analyzed.

Result

Of the 707 NF patients, 40 (5.66%) died in the hospital. The median (interquartile range) blood lactate level in all NF patients was 3.6 mmol/l (2.2–4.8). The blood lactate level upon ED arrival was significantly associated with mortality (odds ratio [OR] = 1.35; 95% confidence interval [CI], 1.30–1.46; P < 0.001), even after adjustment for age and SOFA score (OR = 1.27; P < 0.001). Multivariate regression analysis showed that a high blood lactate level (OR = 1.17; 95% CI, 1.07–1.29; P = 0.001) and a high SOFA score (OR = 1.15; 95% CI, 1.11–1.20; P < 0.001) were independent risk factors for in-hospital mortality in NF. Blood lactate achieved an area under-the-receiver-operating-characteristic curve (AUC) of 0.79 (P < 0.001) for predicting mortality that was similar to that of SOFA score (AUC = 0.82; P < 0.001). Blood lactate displayed a sensitivity of 62% and a specificity of 86% in predicting mortality at the optimal cutoff value of 5.80 mmol/l.

Conclusion

In necrotizing fasciitis patients, hyperlactatemia on ED arrival is independently associated with in-hospital mortality. NF patients with hyperlactatemia on ED arrival should be closely monitored for signs of deterioration and consider early and aggressive intervention to prevent mortality.

Necrotizing Soft Tissue Infections in the Vasculopathic Patient: Review of Literature

Background:

Necrotizing soft tissue infection is a surgical emergency associated with high mortality. Its presence in patients with risk factors for peripheral arterial disease such as diabetes mellitus is consistently associated with significantly poorer outcomes. Though it has been over a century since it was initially described in the literature, mortality rates remain high and treatment regimens are not standardized.

Materials and methods:

PubMed and Cochrane databases were searched for articles pertaining to necrotizing soft tissue infections. Articles were screened for relevance with the intent to compare outcomes in prospective studies of patients with diabetes mellitus or peripheral arterial disease. Patient demographics, clinical findings, mortality, rates of amputation, and morbidity were intended to be compared.

Results:

857 articles were identified, 165 duplicates were removed, and 6 prospective trials were identified for inclusion. Due to significant paucity of data, patient heterogeneity, and lack of standardization for surgical management, a descriptive review of the literature in relation to necrotizing soft tissue infections was pursued, with a focus on high-risk patients with peripheral arterial disease or diabetes mellitus.

Conclusions:

Early aggressive surgical intervention or major amputation may reduce mortality at the cost of increased disability and poorer quality of life in the long term, and may be appropriate in vasculopaths with poorly controlled diabetes and rapidly progressive fulminant infection. However, there is a deficiency in high-level evidence supporting surgical decision-making in this setting, with no standardized protocols for amputation. Future research will be needed to clarify the patient population who would benefit from radical amputation versus intention for limb salvage.

Diagnostic Performance of Initial Serum Albumin Level for Predicting In-Hospital Mortality among Necrotizing Fasciitis Patients

Background: Hypoalbuminemia is known to be associated with adverse outcomes in critical illness. In this study, we attempted to identify whether hypoalbuminemia on emergency department (ED) arrival is a reliable predictor for in-hospital mortality in necrotizing fasciitis (NF). patients. Method: A retrospective cohort study of hospitalized adult patients with NF was conducted in a tertiary teaching hospital in Taiwan between March 2010 and March 2018. Blood samples were collected in the ED upon arrival, and serum albumin levels were determined. We evaluated the predictive value of serum albumin level at ED presentation for in-hospital mortality. All collected data were statistically analyzed. Result: Of the 707 NF patients, 40 (5.66%) died in the hospital. The mean serum albumin level was 3.1 ± 0.9 g/dL and serum albumin levels were significantly lower in the non-survivor group than in the survivor group (2.8 ± 0.7 g/dL vs. 3.5 ± 0.8 g/dL). In the multivariable logistic regression model, albumin was significantly associated with in-hospital mortality (odds ratio (OR) 0.92, 95% confidence interval (CI) 0.88–0.96, p < 0.001). The area under-the-receiver-operating-characteristic curve (AUC) for in-hospital survival was 0.77 (95% CI 0.72–0.82) and corresponding sensitivity, specificity, positive predictive value, negative predictive value, and positive and negative likelihood ratio were 66%, 74%, 33%, 88%, 2.25, and 0.48, respectively. High sensitivity (96%) for survival was shown at albumin level of 4.0 g/dL and high specificity (91%) for mortality was shown at a level of 2.5 g/dL. Conclusion: Initial serum albumin levels strongly predicted in-hospital mortality among patients with necrotizing fasciitis. NF patients with hypoalbuminemia on ED arrival should be closely monitored for signs of deterioration and early and aggressive intervention should be considered to prevent mortality.