GENETIC ABLATION OF THE C-TYPE LECTIN RECEPTOR CLEC2D INCREASES PERITONITIS MORTALITY, INFLAMMATION AND PHYSIOLOGY WITHOUT DIMINISHING ORGAN INJURY.

BACKGROUND: Sepsis accounts for substantial morbidity and mortality motivating investigators to continue the search for pathways and molecules driving the pathogenesis of the disease. The current study examined if the novel C-type Lectin Receptor (CLR), Clec2d, plays a significant role in the pathogenesis of sepsis. METHODS: Clec2d knockout (KO) mice were fully backcrossed onto the C57\BL6 background. Acute endotoxemia was induced with an intraperitoneal (i.p.) injection of lipopolysaccharide (LPS). Sepsis was induced in two different models, Cecal Ligation and Puncture (CLP) and Pseudomonas aeruginosa pneumonia. Both models were treated with antibiotics and fluid resuscitation. In the sepsis models, physiologic and hematologic measurements were measured at 24 hours by collecting a small sample of peripheral blood. Mortality was followed for 14 days. RESULTS: A total of 197 mice were studied, 58 wild type (WT) and 54 knock-out (KO) in the LPS model; 27 wild type and 21 KO mice in the CLP model; and 22 WT and 15 KO mice in the pneumonia model. Clec2d KO mice had greater mortality in the LPS and CLP studies but not the pneumonia model. There were significant differences in multiple parameters determined 24 hours post sepsis between mice who would subsequently died and those lived. Consistent with previous reports in the CLP model, higher concentrations of IL-6, increased numbers of peripheral blood lymphocytes and greater renal injury were found in the dying mice. In contrast, in the pneumonia model IL-6 was higher in the surviving mice, however, the IL-6 levels in the pneumonia model (0.6 ± 0.3 ng/ml mean ± SEM) were less than 2% of the IL-6 levels of mice that died in the CLP model (41 ± 9 ng/ml, mean ± SEM). There were no differences in the lymphocyte count or renal injury between living and dying mice in the pneumonia model. In both sepsis models dying mice had lower heart rates, respiratory rates, and body temperatures. These values were also lower in the KO mice compared to the WT in CLP, but the breath rate and body temperature were increased in the KO pneumonia mice. CONCLUSION: The C-type lectin receptor Clec2d plays a complicated role in the pathogenesis of sepsis which varies with source of infection as demonstrated in the models used to study the disease. These data highlight the heterogeneity of the responses to sepsis and provide further evidence that a single common pathway driving sepsis organ injury and death likely does not exist.

Application of creatinine height index in patients with trauma for the evaluation of psoas muscle mass: A clinical validation study.

BACKGROUND: The creatinine height index (CHI) is an estimate of lean body mass. We hypothesize that a modified CHI estimate using serum creatinine (sCr) levels in patients with normal renal function when performed soon after injury would reflect preinjury protein nutrition status. METHODS: The urine CHI (uCHI) was calculated using the 24-h urine sample. The serum-derived estimated CHI (sCHI) was calculated using the sCr on admission. Correlation between abdominal computed tomography images at specific lumbar vertebral levels and total body fat and muscle content was used for comparison as an independent measurement of nutrition status unlikely to be substantially altered by trauma. RESULTS: A total of 45 patients were enrolled, all with a significant injury burden (median injury severity score [ISS] = 25; interquartile range, 17-35). The calculated sCHI on admission was 71.0% (SD = 26.9%) and likely underestimates the CHI when compared with uCHI (mean = 112.5%, SD = 32.6%). Stratifying by degree of stress demonstrated that in a group of 23 moderately and severely stressed patients, uCHI (mean = 112.7%, SD = 5.7%) and sCHI (mean = 60.8%, SD = 1.9%) were significantly different and without correlation (r = -0.26, P = 0.91). In patients without stress, there was a significant negative correlation between sCHI and psoas muscle area (r = -0.869, P = 0.03), and in patients with severe stress there was a significant positive correlation between uCHI and psoas muscle area (r = 0.733, P = 0.016). CONCLUSION: The CHI calculated from the initial sCr is not an appropriate estimate of uCHI in critically ill trauma patients and is not a valid measure of psoas muscle mass in this setting.

Machine learning and murine models explain failures of clinical sepsis trials.

BACKGROUND: Multiple clinical trials failed to demonstrate the efficacy of hydrocortisone, ascorbic acid, and thiamine (HAT) in sepsis. These trials were dominated by patients with pulmonary sepsis and have not accounted for differences in the inflammatory responses across varying etiologies of injury/illness. Hydrocortisone, ascorbic acid, and thiamine have previously revealed tremendous benefits in animal peritonitis sepsis models (cecal ligation and puncture [CLP]) in contradiction to the various clinical trials. The impact of HAT remains unclear in pulmonary sepsis. Our objective was to investigate the impact of HAT in pneumonia, consistent with the predominate etiology in the discordant clinical trials. We hypothesized that, in a pulmonary sepsis model, HAT would act synergistically to reduce end-organ dysfunction by the altering the inflammatory response, in a unique manner compared with CLP. METHODS: Using Pseudomonas aeruginosa pneumonia, a pulmonary sepsis model (pneumonia [PNA]) was compared directly to previously investigated intra-abdominal sepsis models. Machine learning applied to early vital signs stratified animals into those predicted to die (pDie) versus predicted to live (pLive). Animals were then randomized to receive antibiotics and fluids (vehicle [VEH]) vs. HAT). Vitals, cytokines, vitamin C, and markers of liver and kidney function were assessed in the blood, bronchoalveolar lavage, and organ homogenates. RESULTS: PNA was induced in 119 outbred wild-type Institute of Cancer Research mice (predicted mortality approximately 50%) similar to CLP. In PNA, interleukin 1 receptor antagonist in 72-hour bronchoalveolar lavage was lower with HAT (2.36 ng/mL) compared with VEH (4.88 ng/mL; p = 0.04). The remaining inflammatory cytokines and markers of liver/renal function showed no significant difference with HAT in PNA. PNA vitamin C levels were 0.62 mg/dL (pDie HAT), lower than vitamin C levels after CLP (1.195 mg/dL). Unlike CLP, PNA mice did not develop acute kidney injury (blood urea nitrogen: pDie, 33.5 mg/dL vs. pLive, 27.6 mg/dL; p = 0.17). Furthermore, following PNA, HAT did not significantly reduce microscopic renal oxidative stress (mean gray area: pDie, 16.64 vs. pLive, 6.88; p = 0.93). Unlike CLP where HAT demonstrated a survival benefit, HAT had no impact on survival in PNA. CONCLUSION: Hydrocortisone, ascorbic acid, and thiamine therapy has minimal benefits in pneumonia. The inflammatory response induced by pulmonary sepsis is unique compared with the response during intra-abdominal sepsis. Consequently, different etiologies of sepsis respond differently to HAT therapy.

Defining Sepsis Phenotypes-Two Murine Models of Sepsis and Machine Learning.

INTRODUCTION: The immunobiology defining the clinically apparent differences in response to sepsis remains unclear. We hypothesize that in murine models of sepsis we can identify phenotypes of sepsis using non-invasive physiologic parameters (NIPP) early after infection to distinguish between different inflammatory states. METHODS: Two murine models of sepsis were used: gram-negative pneumonia (PNA) and cecal ligation and puncture (CLP). All mice were treated with broad spectrum antibiotics and fluid resuscitation. High-risk sepsis responders (pDie) were defined as those predicted to die within 72 h following infection. Low-risk responders (pLive) were expected to survive the initial 72 h of sepsis. Statistical modeling in R was used for statistical analysis and machine learning. RESULTS: NIPP obtained at 6 and 24 h after infection of 291 mice (85 PNA and 206 CLP) were used to define the sepsis phenotypes. Lasso regression for variable selection with 10-fold cross-validation was used to define the optimal shrinkage parameters. The variables selected to discriminate between phenotypes included 6-h temperature and 24-h pulse distention, heart rate (HR), and temperature. Applying the model to fit test data (n = 55), area under the curve (AUC) for the receiver operating characteristics (ROC) curve was 0.93. Subgroup analysis of 120 CLP mice revealed a HR of <620 bpm at 24 h as a univariate predictor of pDie. (AUC of ROC curve = 0.90). Subgroup analysis of PNA exposed mice (n = 121) did not reveal a single predictive variable highlighting the complex physiological alterations in response to sepsis. CONCLUSION: In murine models with various etiologies of sepsis, non-invasive vitals assessed just 6 and 24 h after infection can identify different sepsis phenotypes. Stratification by sepsis phenotypes can transform future studies investigating novel therapies for sepsis.

The impact of English proficiency on outcomes after bariatric surgery.

BACKGROUND: Several studies demonstrated language that discordant care between may lead to mixed outcomes and increased use of hospital-resources. In the setting of bariatric surgery, which relies heavily on intensive pre-operative and post-operative counseling, we hypothesized that patients with LEP would have less favorable outcomes compared to English-proficient (EP) patients. METHODS: All patients 18 years and older, who underwent laparoscopic sleeve gastrectomy (SG) or laparoscopic gastric bypass (LGBP) from January 2013 to December 2017 were included. Language proficiency was determined by chart review for the use of an interpreter at least once during the study period. Outcomes of interest at 30-days and 1 year included: emergency department (ED) visits, readmission, length of stay (LOS), chief-complaint on readmission, and post-operative complications. Additionally, comorbidity remission and weight loss at one year was recorded. RESULTS: A total of 671 patients were categorized as LEP (40%) and spoke 6 unique languages. Within the 1 year post-operative period, EP patients presented to the ED more than LEP patients (23% vs. 14% p < 0.001). After multivariable regression for potential confounders this difference persisted; adjusted OR = 0.65 (95% CI 0.43-0.95; p = 0.029). However, despite more frequent ED visits by EP patients, there was no significant difference in readmission within one year; adjusted OR = 0.94 (95% CI 0.56-1.55; p = 0.50). Both groups demonstrated similar successful weight loss at 1 year: EP-31.85% (LGBP) and - 28.02% (SG) vs. LEP-30.17% (LGBP) and - 28.36% (SG). EP and LEP patients also had similar remission of obesity-related comorbidities. CONCLUSION: There were no differences in outcomes following bariatric surgery when comparing patients with limited English proficiency to those who are proficient in English. Bariatric surgical care can be delivered in a safe and effective manner with equivalent outcomes between patients who are and are not English-language proficient.

Early metabolic support for critically ill trauma patients: A prospective randomized controlled trial.

BACKGROUND: There is a lack of consensus regarding the optimal nutritional support for trauma patients. We hypothesize that early postinjury metabolic support focusing on adequate protein would modify the metabolic signature and alter the inflammatory environment for critically ill trauma patients. METHODS: We conducted a prospective randomized controlled pilot trial for adult patients admitted to the surgical intensive care unit following traumatic injury. Patients were randomized to receive early metabolic support (EMS) (peripheral amino acid infusions) or standard of care (enteral nutrition as soon as feasible). Routine laboratory assessments, nitrogen balance, cytokines, and metabolomic analyses were assessed at baseline and day 5 after intervention. RESULTS: A total of 42 trauma patients were randomized into well-balanced groups with similar age (32 years), Injury Severity Score (25), and body mass index (27.4 kg/m2). Early metabolic support provided significantly more protein (1.43 g/kg vs. 0.35 g/kg; p < 0.0001) and more calories (12.6 kcal/kg vs. 7.5 g/kg; p = 0.0012) over the first 5 days as compared with the standard of care. Early metabolic support modified protein catabolism and synthesis as demonstrated by a larger median negative nitrogen balance (-16.3 g vs. -5.3 g; p = 0.03) and a unique metabolomic profile at day 5. The biochemical profile of patients who received EMS was defined by greater declines in circulating levels of stress hormone precursors and increased levels of amino acids. The inflammatory response following EMS resulted in a greater decrease in interleukin-1B (p = 0.02) and increase in soluble interleukin-6 receptor (p = 0.01) between baseline and day 5 as compared with the standard of care. The EMS group had a decreased length of stay (15 vs. 22 days) and decreased surgical intensive care unit length of stay (8 vs. 9 days); however, this disappeared after adjustment for Injury Severity Score in this small population. CONCLUSIONS: Early metabolic support with amino acid is safe, modifies metabolism, and may downregulate the inflammatory state associated with significant trauma, warranting a larger trial to assess for improved outcomes. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level II.

Cytokine Drizzle-The Rationale for Abandoning "Cytokine Storm".

BACKGROUND: "Cytokine storm" has been used to implicate increased cytokine levels in the pathogenesis of serious clinical conditions. Similarities with Severe Acute Respiratory Syndrome Coronoavirus-2 (SARS CoV-2) and the 2012 Middle Eastern Respiratory Syndrome led early investigators to suspect a "cytokine storm" resulting in an unregulated inflammatory response associated with the significant morbidity and mortality induced by SARS CoV-2. The threshold of blood cytokines necessary to qualify as a "cytokine storm" has yet to be defined. METHODS: A literature review was conducted to identify cytokine levels released during 11 assorted clinical conditions or diseases. Weighted averages for various cytokines were calculated by multiplying the number of patients in the paper by the average concentration of each cytokine. Correlation between cytokine levels for individual conditions or diseases were assessed using Pearson correlation coefficient. RESULTS: The literature was reviewed to determine blood levels of cytokines in a wide variety of clinical conditions. These conditions ranged from exercise and autoimmune disease to septic shock and therapy with chimeric antigen receptor T cells. The most frequently measured cytokine was IL-6 which ranged from 24,123 pg/mL in septic shock to 11 pg/mL after exercise. In patients with severe SARS CoV-2 infections, blood levels of IL-6 were only 43 pg/mL, nearly three magnitudes lower than IL-6 levels in patients with septic shock. The clinical presentations of these different diseases do not correlate with blood levels of cytokines. Additionally, there is poor correlation between the concentrations of different cytokines among the different diseases. Specifically, blood levels of IL-6 did not correlate with levels of IL-8, IL-10, or TNF. Septic shock had the highest concentrations of cytokines, yet multiple cytokine inhibitors have failed to demonstrate improved outcomes in multiple clinical trials. Patients with autoimmune diseases have very low blood levels of cytokines (rheumatoid arthritis, IL-6 = 34 pg/mL; Crohn's disease, IL-6 = 5 pg/mL), yet respond dramatically to cytokine inhibitors. CONCLUSION: The misleading term "cytokine storm" implies increased blood levels of cytokines are responsible for a grave clinical condition. Not all inflammatory conditions resulting in worsened disease states are correlated with significantly elevated cytokine levels, despite an association with the term "cytokine storm". "Cytokine storm" should be removed from the medical lexicon since it does not reflect the mediators driving the disease nor does it predict which diseases will respond to cytokine inhibitors.

Amplifying inequity: The compounding impact of COVID-19 and violence.

While "stay-at-home" orders for COVID-19 were in effect, many American cities witnessed a rise in community and interpersonal violence. Our own institution, the largest regional trauma facility and Boston's safety net hospital, saw a paradoxical rise in penetrating violent trauma admissions despite decreases in other hospital admissions, leading to our most violent summer in five years. It has been established that minoritized and marginalized communities have faced the harshest impacts of the pandemic. Our findings suggest that the conditions created by the COVID-19 pandemic have amplified the inequities that exist in communities of color that place them at risk for exposure to violence. The pandemic has served to potentiate the impacts of violence already plaguing the communities and patients we serve.

Implementation of an Intraoperative Instructional Timeout Just Prior to Stapler Use Improves Proficiency of Surgical Stapler Usage by Surgery Residents.

INTRODUCTION: With the fragmented rotational structure of training, exposure to surgical staplers is not uniform across surgical residents. Traditionally, educational sessions dedicated to instruction in surgical staplers have taken place outside the operating room. This study implemented and evaluated an intraoperative timeout immediately prior to stapler use in cases with surgical residents. METHODS: During general surgery cases from June 1, 2017 until December 31, 2017, surgical teams, including the surgical attending, surgical resident, and scrub nurse participated in an intraoperative instructional timeout, during which proper use of linear or circular staplers was reviewed. At the conclusion of the timeout, residents were required to demonstrate proper stapler assembly and verbalize all technical steps involved in stapler use. Duration of each timeout was recorded. Immediately following the case, a pre-post survey was administered to each participating junior (R1-R2) or senior (R4-R5) surgical resident. The primary outcome was change in stapler use knowledge by surgical residents. Survey questions with Likert scale responses were analyzed using paired ttests, and responses from junior residents were compared to those from senior residents with independent t tests. RESULTS: Forty-three general surgery cases involved stapler use during the study period and implemented an intraoperative instructional timeout. The educational intervention increased stapler use knowledge significantly in all surgical residents. Prior to the timeout, junior residents reported significantly higher anxiety related to stapler usage compared to their senior counterparts; anxiety scores in junior residents decreased significantly for use of both linear and circular staplers. The mean timeout duration was 2.9 minutes (standard deviation 0.9 minutes, range 1.2-4.6 minutes). All participating surgical residents recommended routine implementation of an instructional timeout prior to intraoperative stapler use. CONCLUSIONS: An intraoperative timeout dedicated to stapler teaching is effective in increasing proficiency and easing anxiety in all levels of surgical residents. Further research is warranted to determine whether this educational intervention would translate into fewer stapler use errors and decreased intraoperative complications.

Perceptions in rib injuries: A multidisciplinary single center survey of clinician differences in risk stratification and management of patients with rib fractures.

BACKGROUND: Although associated with significant morbidity, there is no universally accepted management of rib fractures. We hypothesized that variations in risk stratification may influence this. METHODS: A questionnaire was developed to assess providers' perceived risk factors and injury stratification of rib fracture patients at a Level 1 trauma center. RESULTS: There were 143 responses (36% physician response rate). Hypoxia, age, number of ribs fractured, pre-existing pulmonary disease, and flail chest were identified as the most important risk factors determining morbidity and mortality in blunt chest trauma. While clinicians agreed on predicted mortality for <2 fractured ribs, significant variation for 5-6 and >8 rib fractures was seen. EM and surgery providers significantly differed in assessment of injury severity. CONCLUSION: Providers identified common risk factors for increased morbidity and mortality. However, the difference in perceived severity between providers indicates a need for clinical tools to assist in better standardizing rib fracture management.

Outcomes of preinjury anticoagulation in patients with traumatic rib fractures.

BACKGROUND: Anticoagulant and antiplatelet agents (ACAP) have been shown to negatively affect trauma patients. METHODS: Outcomes in adults with rib fractures were reviewed. Pearson chi-square test was used for analysis. Multivariate logistic regression was used to adjust for potential confounders. RESULTS: Of the 1448 included patients, 149 (10.3%) took preinjury ACAP; these patients were significantly older than non-anticoagulated patients (72 vs. 54 years, P ≤ 0.05). There was no difference in pulmonary complications, ICU admissions or ICU LOS. The preinjury ACAP group had a significantly longer LOS (12.03 vs. 9.33 days, P = 0.004), fewer pulmonary contusions (15.43% vs. 22.94%, P = 0.037), and fewer thoracic drainage procedures (10.74% vs. 18.17%, P = 0.023). Multivariate adjustment for possible confounders revealed that patients taking warfarin had a significantly longer LOS (+7.38 days). After adjustment there was no difference in mortality. CONCLUSION: Preinjury ACAP use does not increase mortality or morbidity in patients with rib fractures. SUMMARY: We demonstrated that preinjury anticoagulation and antiplatelet agents do not increase mortality or morbidity in patients with rib fractures. However, they lead to a longer hospital length of stay, particularly in patients on warfarin.

Mutations in CSPP1 cause primary cilia abnormalities and Joubert syndrome with or without Jeune asphyxiating thoracic dystrophy.

Joubert syndrome (JBTS) is a recessive ciliopathy in which a subset of affected individuals also have the skeletal dysplasia Jeune asphyxiating thoracic dystrophy (JATD). Here, we have identified biallelic truncating CSPP1 (centrosome and spindle pole associated protein 1) mutations in 19 JBTS-affected individuals, four of whom also have features of JATD. CSPP1 mutations explain ∼5% of JBTS in our cohort, and despite truncating mutations in all affected individuals, the range of phenotypic severity is broad. Morpholino knockdown of cspp1 in zebrafish caused phenotypes reported in other zebrafish models of JBTS (curved body shape, pronephric cysts, and cerebellar abnormalities) and reduced ciliary localization of Arl13b, further supporting loss of CSPP1 function as a cause of JBTS. Fibroblasts from affected individuals with CSPP1 mutations showed reduced numbers of primary cilia and/or short primary cilia, as well as reduced axonemal localization of ciliary proteins ARL13B and adenylyl cyclase III. In summary, CSPP1 mutations are a major cause of the Joubert-Jeune phenotype in humans; however, the mechanism by which these mutations lead to both JBTS and JATD remains unknown.