Current fistula management.

PURPOSE OF REVIEW: Enterocutaneous fistulas (ECFs) pose a significant impact in the healthcare system, both financially and in resource utilization. Delivery of optimal care is complex and involves intensive wound care, complex nutritional delivery and multidisciplinary care teams for optimization. Recently, there have been pushes to modernize the traditional approach to ECF care to a new paradigm of protocol-based individualized delivery of care. RECENT FINDINGS: There is an increased trend towards pushing enteral nutrition for the management of ECF patients. Adjuncts, including improved fistuloclysis devices, supplements and absorptive aides have challenged the conventional dogma of ECF treatment. There has also been increased focus on surgical prehabilitation and the ability to improve patient outcomes. SUMMARY: ECF care is complex and requires a multidisciplinary approach focused on source control, nutritional optimization with focus on enteral nutrition, wound care and prehabilitation.

Nutritional impact of omega 3 fatty acids and metabolites in acute and chronic critical illness.

PURPOSE OF REVIEW: Lipids have been utilized historically as a calorie dense means to ensure delivery of essential fatty acids (FA). Since the development of mixed lipid emulsion and investigation of immunomodulatory formulas, there has been an awakening that not all lipids are created equal. This narrative review focuses on contemporary evidence in the utilization of lipids (namely omega 3 fatty acids) in both acute and chronic critical illness. RECENT FINDINGS: Though randomized control trials and meta-analyses provide little guidance regarding clinical practice for patients suffering from chronic critical illness, available literature suggests the potential to use lipid formulas to decrease the inflammatory cycle that drives catabolism. Additionally, this review will address the expanding evidence that specialized pro-resolving mediators (SPMs) may be the future of immunomodulating inflammation in acute and chronic critical illness and the persistent inflammation, immunosuppression, and catabolic syndrome (PICS). SUMMARY: Although societal guidelines, expert consensus, and literature support the use of omega 3 fatty acids in the acute critically ill population, more research is needed regarding omega 3 fatty acids for chronic critical illness and PICS.

Human Myeloid-derived Suppressor Cells are Associated With Chronic Immune Suppression After Severe Sepsis/Septic Shock.

OBJECTIVE: We hypothesized that after sepsis in humans, MDSCs will be persistently increased, functionally immunosuppressive, and associated with adverse clinical outcomes. BACKGROUND: Cancer and sepsis have surprisingly similar immunologic responses and equally dismal long term consequences. In cancer, increased myeloid-derived suppressor cells (MDSCs) induce detrimental immunosuppression, but little is known about the role of MDSCs after sepsis. METHODS: Blood was obtained from 74 patients within 12 hours of severe sepsis/septic shock (SS/SS), and at set intervals out to 28 days, and also in 18 healthy controls. MDSCs were phenotyped for cell surface receptor expression and enriched by cell sorting. Functional and genome-wide expression analyses were performed. Multiple logistic regression analysis was conducted to determine if increased MDSC appearance was associated with in-hospital and long-term outcomes. RESULTS: After SS/SS, CD33CD11bHLA-DR MDSCs were dramatically increased out to 28 days (P < 0.05). When co-cultured with MDSCs from SS/SS patients, antigen-driven T-cell proliferation and TH1/TH2 cytokine production were suppressed (P < 0.05). Additionally, septic MDSCs had suppressed HLA gene expression and up-regulated ARG1 expression (P < 0.05). Finally, SS/SS patients with persistent increased percentages of blood MDSCs had increased nosocomial infections, prolonged intensive care unit stays, and poor functional status at discharge (P < 0.05). CONCLUSIONS: After SS/SS in humans, circulating MDSCs are persistently increased, functionally immunosuppressive, and associated with adverse outcomes. This novel observation warrants further studies. As observed in cancer immunotherapy, MDSCs could be a novel component in multimodality immunotherapy targeting detrimental inflammation and immunosuppression after SS/SS to improve currently observed dismal long-term outcomes.

A Detailed Characterization of the Dysfunctional Immunity and Abnormal Myelopoiesis Induced by Severe Shock and Trauma in the Aged.

The elderly are particularly susceptible to trauma, and their outcomes are frequently dismal. Such patients often have complicated clinical courses and ultimately die of infection and sepsis. Recent research has revealed that although elderly subjects have increased baseline inflammation as compared with their younger counterparts, the elderly do not respond to severe infection or injury with an exaggerated inflammatory response. Initial retrospective analysis of clinical data from the Glue Grant trauma database demonstrated that despite a similar frequency, elderly trauma patients have worse outcomes to pneumonia than younger subjects do. Subsequent analysis with a murine trauma model also demonstrated that elderly mice had increased mortality after posttrauma Pseudomonas pneumonia. Blood, bone marrow, and bronchoalveolar lavage sample analyses from juvenile and 20-24-mo-old mice showed that increased mortality to trauma combined with secondary infection in the aged are not due to an exaggerated inflammatory response. Rather, they are due to a failure of bone marrow progenitors, blood neutrophils, and bronchoalveolar lavage cells to initiate and complete an emergency myelopoietic response, engendering myeloid cells that fail to clear secondary infection. In addition, elderly people appeared unable to resolve their inflammatory response to severe injury effectively.

Patterns of gene expression among murine models of hemorrhagic shock/trauma and sepsis.

Controversy remains whether the leukocyte genomic response to trauma or sepsis is dependent upon the initiating stimulus. Previous work illustrated poor correlations between historical models of murine trauma and sepsis (i.e., trauma-hemorrhage and lipopolysaccharide injection, respectively). The aim of this study is to examine the early genomic response in improved murine models of sepsis [cecal ligation and puncture (CLP)] and trauma [polytrauma (PT)] with and without pneumonia (PT+Pp). Groups of naïve, CLP, PT, and PT+Pp mice were killed at 2 h, 1 or 3 days. Total leukocytes were isolated for genome-wide expression analysis, and genes that were found to differ from control (false discovery rate adjusted P < 0.001) were assessed for fold-change differences. Spearman correlations were also performed. For all time points combined (CLP, PT, PT+Pp), there were 10,426 total genes that were found to significantly differ from naïve controls. At 2 h, the transcriptomic changes between CLP and PT showed a positive correlation (rs) of 0.446 (P < 0.0001) but were less positive thereafter. Correlations were significantly improved when we limited the analysis to common genes whose expression differed by a 1.5 fold-change. Both pathway and upstream analyses revealed the activation of genes known to be associated with pathogen-associated and damage-associated molecular pattern signaling, and early activation patterns of expression were very similar between polytrauma and sepsis at the earliest time points. This study demonstrates that the early leukocyte genomic response to sepsis and trauma are very similar in mice.

Protective immunity and defects in the neonatal and elderly immune response to sepsis.

Populations encompassing extremes of age, including neonates and elderly, have greater mortality from sepsis. We propose that the increased mortality observed in the neonatal and elderly populations after sepsis is due to fundamental differences in host-protective immunity and is manifested at the level of the leukocyte transcriptome. Neonatal (5-7 d), young adult (6-12 wk), or elderly (20-24 mo) mice underwent a cecal slurry model of intra-abdominal sepsis. Both neonatal and elderly mice exhibited significantly greater mortality to sepsis (p < 0.05). Neonates in particular exhibited significant attenuation of their inflammatory response (p < 0.05), as well as reductions in cell recruitment and reactive oxygen species production (both p < 0.05), all of which could be confirmed at the level of the leukocyte transcriptome. In contrast, elderly mice were also more susceptible to abdominal peritonitis, but this was associated with no significant differences in the magnitude of the inflammatory response, reduced bacterial killing (p < 0.05), reduced early myeloid cell activation (p < 0.05), and a persistent inflammatory response that failed to resolve. Interestingly, elderly mice expressed a persistent inflammatory and immunosuppressive response at the level of the leukocyte transcriptome, with failure to return to baseline by 3 d. This study reveals that neonatal and elderly mice have profoundly different responses to sepsis that are manifested at the level of their circulating leukocyte transcriptome, although the net result of increased mortality is similar. Considering these differences are fundamental aspects of the genomic response to sepsis, interventional therapies will require individualization based on the age of the population.

Aged mice are unable to mount an effective myeloid response to sepsis.

The elderly have increased morbidity and mortality following sepsis; however, the cause(s) remains unclear. We hypothesized that these poor outcomes are due in part to defects in innate immunity, rather than to an exaggerated early inflammatory response. Young (6-12 wk) or aged (20-24 mo) mice underwent polymicrobial sepsis, and subsequently, the aged mice had increased mortality and defective peritoneal bacterial clearance compared with young mice. No differences were found in the magnitude of the plasma cytokine responses. Although septic aged mice displayed equivalent or increased numbers of circulating, splenic, and bone marrow myeloid cells, some of these cells exhibited decreased phagocytosis, reactive oxygen species production, and chemotaxis. Blood leukocyte gene expression was less altered in aged versus young mice 1 d after sepsis. Aged mice had a relative inability to upregulate gene expression of pathways related to neutrophil-mediated protective immunity, chemokine/chemokine receptor binding, and responses to exogenous molecules. Expression of most MHC genes remained more downregulated in aged mice at day 3. Despite their increased myeloid response to sepsis, the increased susceptibility of aged mice to sepsis appears not to be due to an exaggerated inflammatory response, but rather, a failure to mount an effective innate immune response.

Advanced age is associated with worsened outcomes and a unique genomic response in severely injured patients with hemorrhagic shock.

INTRODUCTION: We wished to characterize the relationship of advanced age to clinical outcomes and to transcriptomic responses after severe blunt traumatic injury with hemorrhagic shock. METHODS: We performed epidemiological, cytokine, and transcriptomic analyses on a prospective, multi-center cohort of 1,928 severely injured patients. RESULTS: We found that there was no difference in injury severity between the aged (age ≥55, n = 533) and young (age <55, n = 1395) cohorts. However, aged patients had more comorbidities. Advanced age was associated with more severe organ failure, infectious complications, ventilator days, and intensive care unit length of stay, as well as, an increased likelihood of being discharged to skilled nursing or long-term care facilities. Additionally, advanced age was an independent predictor of a complicated recovery and 28-day mortality. Acutely after trauma, blood neutrophil genome-wide expression analysis revealed an attenuated transcriptomic response as compared to the young; this attenuated response was supported by the patients' plasma cytokine and chemokine concentrations. Later, these patients demonstrated gene expression changes consistent with simultaneous, persistent pro-inflammatory and immunosuppressive states. CONCLUSIONS: We concluded that advanced age is one of the strongest non-injury related risk factors for poor outcomes after severe trauma with hemorrhagic shock and is associated with an altered and unique peripheral leukocyte genomic response. As the general population's age increases, it will be important to individualize prediction models and therapeutic targets to this high risk cohort.

A better understanding of why murine models of trauma do not recapitulate the human syndrome.

OBJECTIVE: Genomic analyses from blood leukocytes have concluded that mouse injury poorly reflects human trauma at the leukocyte transcriptome. Concerns have focused on the modest severity of murine injury models, differences in murine compared with human age, dissimilar circulating leukocyte populations between species, and whether similar signaling pathways are involved. We sought to examine whether the transcriptomic response to severe trauma in mice could be explained by these extrinsic factors, by utilizing an increasing severity of murine trauma and shock in young and aged mice over time, and by examining the response in isolated neutrophil populations. DESIGN: Preclinical controlled in vivo laboratory study and retrospective cohort study. SETTING: Laboratory of Inflammation Biology and Surgical Science and multi-institution level 1 trauma centers. SUBJECTS: Six- to 10-week-old and 20- to 24-month-old C57BL/6 (B6) mice and two cohorts of 167 and 244 severely traumatized (Injury Severity Score > 15) adult (> 18 yr) patients. INTERVENTIONS: Mice underwent one of two severity polytrauma models of injury. Total blood leukocyte and neutrophil samples were collected. MEASUREMENTS AND MAIN RESULTS: Fold expression changes in leukocyte and neutrophil genome-wide expression analyses between healthy and injured mice (p < 0.001) were compared with human total and enriched blood leukocyte expression analyses of severe trauma patients at 0.5, 1, 4, 7, 14, and 28 days after injury (Glue Grant trauma-related database). We found that increasing the severity of the murine trauma model only modestly improved the correlation in the transcriptomic response with humans, whereas the age of the mice did not. In addition, the genome-wide response to blood neutrophils (rather than total WBC) was also not well correlated between humans and mice. However, the expression of many individual gene families was much more strongly correlated after injury in mice and humans. CONCLUSIONS: Although overall transcriptomic association remained weak even after adjusting for the severity of injury, age of the animals, timing, and individual leukocyte populations, there were individual signaling pathways and ontogenies that were strongly correlated between mice and humans. These genes are involved in early inflammation and innate/adaptive immunity.

Is there value in plasma cytokine measurements in patients with severe trauma and sepsis?

For the past thirty years, since IL-1ß and TNFα were first cloned, there have been efforts to measure plasma cytokine concentrations in patients with severe sepsis and trauma, and to use these measurements to predict clinical outcome and response to therapies. The numbers of cytokines and chemokines that have been measured in the plasma have literally exploded with the development of multiplex immune approaches. Dozens of relatively small cohort studies have shown plasma cytokine concentrations correlating with outcome in sepsis and trauma. Despite what appears to be a consensus that plasma cytokine concentrations should be useful in the clinical setting, only two cytokines, IL-6 and procalcitonin, have approached routine clinical use. IL-6 has been used as a research tool for entry into sepsis-intervention trials, while procalcitonin is being used clinically at a large number of institutions to distinguish sepsis from other inflammatory processes. For most cytokines, the relative lack of sensitivity and specificity of individual or multiplex cytokine measurements has hindered their utility to predict clinical trajectory in individual patients. The problem rests with a general misunderstanding of cytokine biology, failing to appreciate the general paracrine nature of these mediators, the presence of binding proteins, chaperones and inhibitors in the plasma, and the rapid clearance of these proteins by binding to cell receptors and clearance predominantly by the kidney. The future of using plasma cytokine measurements as an indicator of sepsis/trauma severity or predicting outcome is generally behind us, although there is optimism that procalcitonin measurements may ultimately prove to have utility in the diagnosis of severe sepsis.

Obesity and Associated Outcomes for Blunt vs Penetrating Mechanism in Trauma Laparotomy Patients.

Obesity in trauma patients is an established risk factor contributing to postoperative complications, but the relationship between body mass index (BMI) and trauma patient outcomes is not well-defined, especially when stratified by mechanism of injury. We surveyed the trauma laparotomy registry at an academic level 1 trauma center over a 3-year period to identify mortality, injury severity score, and hospital length of stay (hLOS) outcome measures across BMI classes, with further stratification by mechanism of injury: blunt vs penetrating trauma. A total of 442 patients were included with mean age 44.6 (SD = 18.7) and mean BMI 28.55 (SD = 7.37). These were subdivided into blunt trauma (n = 313) and penetrating trauma (n = 129). Within the blunt trauma subgroup, the hLOS among patients who survived hospitalization significantly increased 9% for each successive BMI class (P = .022, 95% CI = 1.29-17.5). We conclude that successive increase in BMI class is associated with longer hospital stay for blunt trauma patient survivors requiring laparotomy, though additional analysis is needed to establish this relationship to other outcome measures and among penetrating trauma patients.

Chronic Critical Illness and PICS Nutritional Strategies.

The nutritional hallmark of chronic critical illness (CCI) after sepsis is persistent inflammation, immunosuppression, and catabolism syndrome (PICS), which results in global resistance to the anabolic effect of nutritional supplements. This ultimately leaves these patients in a downward phenotypic spiral characterized by cachexia with profound weakness, decreased capacity for rehabilitation, and immunosuppression with the propensity for sepsis recidivism. The persistent catabolism is driven by a pathologic low-grade inflammation with the inability to return to homeostasis and by ongoing increased energy expenditure. Better critical care support systems and advances in technology have led to increased intensive care unit (ICU) survival, but CCI due to PICS with poor long-term outcomes has emerged as a frequent phenotype among ICU sepsis survivors. Unfortunately, therapies to mitigate or reverse PICS-CCI are limited, and recent evidence supports that these patients fail to respond to early ICU evidence-based nutrition protocols. A lack of randomized controlled trials has limited strong recommendations for nutrition adjuncts in these patients. However, based on experience in other conditions characterized by a similar phenotype, immunonutrients aimed at counteracting inflammation, immunosuppression, and catabolism may be important for improving outcomes in PICS-CCI patients. This manuscript intends to review several immunonutrients as adjunctive therapies in treating PICS-CCI.

Audiovisual Modules to Enhance Informed Consent in the ICU: A Pilot Study.

Obtaining informed consent for commonly performed ICU procedures is often compromised by variability in communication styles and inadequate verbal descriptions of anatomic concepts. The objective of this study was to evaluate the efficacy of an audiovisual module in improving the baseline knowledge of ICU procedures among patients and their caregivers. DESIGN: Prospective, observational study. SETTING: Forty-eight-bed adult surgical ICU at a tertiary care center. SUBJECTS: Critically ill surgical patients and their legally authorized representatives. INTERVENTIONS: An audiovisual module describing eight commonly performed ICU procedures. MEASUREMENTS AND MAIN RESULTS: Fifty-nine subjects were enrolled and completed an 11-question pre- and postvideo test of knowledge regarding commonly performed ICU procedures and a brief satisfaction survey. Twenty-nine percent had a healthcare background. High school was the highest level of education for 37% percent of all subjects. Out of 11 questions on the ICU procedure knowledge test, subjects scored an average 8.0 ± 1.9 correct on the pretest and 8.4 ± 2.0 correct on the posttest (p = 0.055). On univariate logistic regression, having a healthcare background was a negative predictor of improved knowledge (odds ratio, 0.185; 95% CI, 0.045-0.765), indicating that those with a health background had a lower probability of improving their score on the posttest. Among subjects who did not have a healthcare background, scores increased from 7.7 ± 1.9 to 8.3 ± 2.1 (p = 0.019). Seventy-five percent of all subjects indicated that the video was easy to understand, and 70% believed that the video improved their understanding of ICU procedures. CONCLUSIONS: Audiovisual modules may improve knowledge and comprehension of commonly performed ICU procedures among critically ill patients and caregivers who have no healthcare background.

A protocol for the management of adhesive small bowel obstruction.

BACKGROUND: Differentiating between partial adhesive small bowel obstruction (aSBO) likely to resolve with medical management and complete obstruction requiring operative intervention remains elusive. We implemented a standardized protocol for the management of aSBO and reviewed our experience retrospectively. METHODS: Patients with symptoms of aSBO were admitted for intravenous fluid resuscitation, bowel rest, nasogastric tube decompression, and abdominal examinations every 4 hours. Laboratory values and a computed tomography scan of the abdomen and pelvis with intravenous contrast were obtained. Patients with peritonitis or computed tomography scan findings suggesting bowel compromise were taken to the operating room for exploration following resuscitation. All other patients received 80 mL of Gastroview (GV) and 40 mL of sterile water via nasogastric tube. Abdominal plain films were obtained at 4, 8, 12, and 24 hours. If contrast did not reach the colon within 24 hours, then operative intervention was performed. RESULTS: Over 1 year, 91 patients were admitted with aSBO. Sixty-three patients received GV, of whom 51% underwent surgery. Twenty-four patients went directly to the operating room because of clinical or imaging findings suggesting bowel ischemia. Average time to surgery was within 1 day for the no-GV group and 2 days for the GV group. Patients passing GV to the colon within 5 hours of administration had a 90% rate of resolution of obstruction. There was a direct relationship between the duration of time before passing GV to the colon and hospital length of stay (HLOS) (r = 0.459). Patients who received GV and did not require surgery had lower HLOS (3 days vs. 11 days, p < 0.0001). CONCLUSION: The GV protocol facilitated early recognition of complete obstruction. Administration of GV had diagnostic and therapeutic value and did not increase HLOS, morbidity, or mortality. LEVEL OF EVIDENCE: Therapeutic study, level V. Epidemiologic study, level V.

Clostridium difficile Infections after Blunt Trauma: A Different Patient Population?

BACKGROUND: The epidemiology of Clostridium difficile-associated infection (CDI) has changed, and it is evident that susceptibility is related not only to exposures and bacterial potency, but host factors as well. Several small studies have suggested that CDI after trauma is associated with a different patient phenotype. The purpose of this study was to examine and describe the epidemiologic factors associated with C. difficile in blunt trauma patients without traumatic brain injury using the Trauma-Related Database as a part of the "Inflammation and Host Response to Injury" (Glue Grant) and the University of Florida Integrated Data Repository. METHODS: Previously recorded baseline characteristics, clinical data, and outcomes were compared between groups (67 C. difficile and 384 uncomplicated, 813 intermediate, and 761 complicated non-C. difficile patients) as defined by the Glue Grant on admission and at days seven and 14. RESULTS: The majority of CDI patients experienced complicated or intermediate clinical courses. The mean ages of all cohorts were less than 65 y and CDI patients were significantly older than uncomplicated patients without CDI. The CDI patients had increased days in the hospital and on the ventilator, as well as significantly higher new injury severity scores (NISS), and a greater percentage of patients with NISS >34 points compared with non-CDI patients. They also had greater Marshall and Denver multiple organ dysfunction scores than non-CDI uncomplicated patients, and greater creatinine, alkaline phosphatase, neutrophil count, lactic acid, and PiO2:FiO2 compared with all non-CDI cohorts on admission. In addition, the CDI patients had higher glucose concentrations and base deficit from uncomplicated patients and greater leukocytosis than complicated patients on admission. Several of these changes persisted to days seven and 14. CONCLUSION: Analysis of severe blunt trauma patients with C. difficile, as compared with non-CDI patients, reveals evidence of increased inflammation, immunosuppression, worse acute kidney injury, higher NISS, greater days in the hospital and on the ventilator, higher organ injury scores, and prolonged clinical courses. This supports reports of an increased prevalence of CDI in a younger population not believed previously to be at risk. This unique population may have specific genomic or inflammation-related risk factors that may play more important roles in disease susceptibility. Prospective analysis may allow early identification of at-risk patients, creation of novel therapeutics, and improved understanding of how and why C. difficile colonization transforms into infection after severe blunt trauma.

Successful implementation of a packed red blood cell and fresh frozen plasma transfusion protocol in the surgical intensive care unit.

BACKGROUND: Blood product transfusions are associated with increased morbidity and mortality. The purpose of this study was to determine if implementation of a restrictive protocol for packed red blood cell (PRBC) and fresh frozen plasma (FFP) transfusion safely reduces blood product utilization and costs in a surgical intensive care unit (SICU). STUDY DESIGN: We performed a retrospective, historical control analysis comparing before (PRE) and after (POST) implementation of a restrictive PRBC/FFP transfusion protocol for SICU patients. Univariate analysis was utilized to compare patient demographics and blood product transfusion totals between the PRE and POST cohorts. Multivariate logistic regression models were developed to determine if implementation of the restrictive transfusion protocol is an independent predictor of adverse outcomes after controlling for age, illness severity, and total blood products received. RESULTS: 829 total patients were included in the analysis (PRE, n=372; POST, n=457). Despite higher mean age (56 vs. 52 years, p=0.01) and APACHE II scores (12.5 vs. 11.2, p=0.006), mean units transfused per patient were lower for both packed red blood cells (0.7 vs. 1.2, p=0.03) and fresh frozen plasma (0.3 vs. 1.2, p=0.007) in the POST compared to the PRE cohort, respectively. There was no difference in inpatient mortality between the PRE and POST cohorts (7.5% vs. 9.2%, p=0.39). There was a decreased risk of urinary tract infections (OR 0.47, 95%CI 0.28-0.80) in the POST cohort after controlling for age, illness severity and amount of blood products transfused. CONCLUSIONS: Implementation of a restrictive transfusion protocol can effectively reduce blood product utilization in critically ill surgical patients with no increase in morbidity or mortality.

Host responses to sepsis vary in different low-lethality murine models.

INTRODUCTION: Animal models for the study of sepsis are being increasingly scrutinized, despite their essential role for early translational research. In particular, recent studies have suggested that at the level of the leukocyte transcriptome, murine models of burns, trauma and endotoxemia markedly differ from their human equivalents, and are only weakly similar amongst themselves. We compared the plasma cytokine and leukocyte transcriptome responses between two different low-lethality murine models of polymicrobial intra-abdominal sepsis. METHODS: Six to ten week male C57BL/6j mice underwent either the 'gold standard' cecal ligation and puncture (CLP) model of intra-abdominal sepsis or administration of a cecal slurry (CS), where cecal contents are injected intraperitoneally. Surviving mice were euthanized at two hours, one or three days after sepsis. RESULTS: The murine leukocyte transcriptomic response to the CLP and CS models of sepsis was surprisingly dissimilar at two hours, one, and three days after sepsis. The Pearson correlation coefficient for the maximum change in expression for the entire leukocyte transcriptome that changed significantly over time (n = 19,071) was R = 0.54 (R2 = 0.297). The CS model resulted in greater magnitude of early inflammatory gene expression changes in response to sepsis with associated increased production of inflammatory chemokines and cytokines. Two hours after sepsis, CLP had more significant expression of genes associated with IL-10 signaling pathways, whereas CS had greater expression of genes related to CD28, apoptosis, IL-1 and T-cell receptor signaling. By three days, the changes in gene expression in both sepsis models were returning to baseline in surviving animals. CONCLUSION: These analyses reveal that the murine blood leukocyte response to sepsis is highly dependent on which model of intra-abdominal sepsis is employed, despite their similar lethality. It may be difficult to extrapolate findings from one murine model to another, let alone to human sepsis.

Persistent inflammation, immunosuppression, and catabolism syndrome after severe blunt trauma.

BACKGROUND: We recently proffered that a new syndrome persistent inflammation, immunosuppression, and catabolism syndrome (PICS) has replaced late multiple-organ failure as a predominant phenotype of chronic critical illness. Our goal was to validate this by determining whether severely injured trauma patients with complicated outcomes have evidence of PICS at the genomic level. METHODS: We performed a secondary analysis of the Inflammation and Host Response to Injury database of adults with severe blunt trauma. Patients were classified into complicated, intermediate, and uncomplicated clinical trajectories. Existing genomic microarray data were compared between cohorts using Ingenuity Pathways Analysis. Epidemiologic data and outcomes were also analyzed between cohorts on admission, Day 7, and Day 14. RESULTS: Complicated patients were older, were sicker, and required increased ventilator days compared with the intermediate/uncomplicated patients. They also had persistent leukocytosis as well as low lymphocyte and albumin levels compared with uncomplicated patients. Total white blood cell leukocyte analysis in complicated patients showed that overall genome-wide expression patterns and those patterns on Days 7 and 14 were more aberrant from control subjects than were patterns from uncomplicated patients. Complicated patients also had significant down-regulation of adaptive immunity and up-regulation of inflammatory genes on Days 7 and 14 (vs. magnitude in fold change compared with control and in magnitude compared with uncomplicated patients). On Day 7, complicated patients had significant changes in functional pathways involved in the suppression of myeloid cell differentiation, increased inflammation, decreased chemotaxis, and defective innate immunity compared with uncomplicated patients and controls. Subset analysis of monocyte, neutrophil, and T-cells supported these findings. CONCLUSION: Genomic analysis of patients with complicated clinical outcomes exhibit persistent genomic expression changes consistent with defects in the adaptive immune response and increased inflammation. Clinical data showed persistent inflammation, immunosuppression, and protein depletion. Overall, the data support the hypothesis that patients with complicated clinical outcomes are exhibiting PICS. LEVEL OF EVIDENCE: Epidemiologic study, level III.