Severity of critical illness correlates with CD3-low expression on iNKT-cells among septic surgical patients

BACKGROUND

iNKT-cells are innate regulatory lymphocytes capable of directing immune and inflammatory responses to sepsis. Repeat stimulation of iNKT-cells leads to the induction of anergy with the emergence of a hyporesponsive CD3low iNKT-cell subpopulation.

METHODS

iNKT-cells were isolated from critical ill surgical patients with sepsis and phenotyped for CD3 expression. This was correlated with degree of severity of illness, as denoted by APACHE-II score.

RESULTS

Comparing healthy volunteers to critically ill septic patients, it was noted that increasing severity of sepsis was associated with increasing frequency of circulating CD3low-iNKT-cell populations.

CONCLUSION

The emergence of CD3low -iNKT-cells may serve as a clinically translatable marker of degree of sepsis-induced immune dysfunction.

The Impact of Protective Devices Across the Spectrum of Trauma Care and Across Racial Groupings

INTRODUCTION

Protective devices such as seat belts and helmets save lives. Most studies only address one aspect of the injury profile - compliance or mortality - not the entire spectrum of trauma care, and little attention is paid to racial differences in the use or impact of protective devices.

METHODS

Patients with blunt mechanisms where using protective devices would be expected were included and were divided into utilizing (P) vs not utilizing protection (Non-P). Chart review included demographics, injuries sustained, hemodynamics, and blood alcohol level. Outcomes included need for emergent operation, complications and death.

RESULTS

Non-P patients were more likely male, presented at night and intoxicated. Highest risk behavior (intoxicated Non-P) presented at night (25.7% of nighttime presentations), and rarely during daytime (6.7% daytime presentations). Non-P were more likely hypotensive and sustain a traumatic brain injury. No race related differences were noted among young patients. Among older (>/=50 years) patients, White patients were least likely Non-P and least likely presented at night. Non-P required more emergent operative intervention, ICU admission, and longer hospital stay. Overall, Non-P was associated with increased risk of death (OR = 1.6 (95% CI = 1.28 - 2.11).

CONCLUSION

Given unique age and racial differences, we advocate for culturally and age specific public service campaigns.

SPLENIC INVARIANT NATURAL KILLER T CELLS PLAY A SIGNIFICANT ROLE IN THE RESPONSE TO POLYMICROBIAL SEPSIS

ABSTRACT

Background: Sepsis is marked by a dysregulated immune response to an infection. Invariant natural killer T cells ( i NKT cells) are a pluripotent lymphocyte subpopulation capable of affecting and coordinating the immune response to sepsis. The spleen is an important site of immune interactions in response to an infection. Splenic i NKT cells have emerged as important potential frontline mediators of chronic immune response. There are few data addressing the role splenic of i NKT cells in response to intra-abdominal polymicrobial sepsis. Methods: The cecal ligation and puncture model was used to create intra-abdominal sepsis in 8- to 12-week-old wild-type, i NKT -/- , or programmed cell death receptor-1 (PD-1) -/- mice. Twenty-four hours later, spleens were harvested. Flow cytometry was used for phenotyping using monoclonal antibodies. Cell sort was used to isolate i NKT cells. A macrophage cell line was used to assess i NKT cell-phagocyte interactions. Enzyme-linked immunosorbent assay was used for cytokine analysis. Results: Splenic i NKT-cell populations rapidly declined following induction of sepsis. Within i NKT-cell -/- mice, a distinct baseline hyperinflammatory environment was noted. Within wild type, sepsis induced an increase in splenic IL-6 and IL-10, whereas in i NKT -/- mice, there was no change in elevated IL-6 levels and a noted decrease in IL-10 expression. Further, following sepsis, PD-1 expression was increased upon spleen i NKT cells. With respect to PD-1 ligands upon phagocytes, PD-1 ligand expression was unaffected, whereas PD-L2 expression was significantly affected by the presence of PD-1. Conclusions: Invariant natural killer T cells play a distinct role in the spleen response to sepsis, an effect mediated by the checkpoint protein PD-1. Given that modulators are available in clinical trials, this offers a potential therapeutic target in the setting of sepsis-induced immune dysfunction.

Bowel Obstruction from an Incidentally Ingested Foreign Body

Small bowel obstructions are common surgical presentations that are most often caused by adhesions following abdominopelvic surgeries. However, in patients with no history of abdominal surgical interventions, assessment of the cause of a small bowel obstruction is more complex, and such patients frequently require operative intervention. We present a case of a 65-year-old man who presented with a small bowel obstruction caused by an inadvertent ingestion of a bread tag that was not identified on preoperative imaging. The sharp end of the bread tag had eroded through the small bowel leading to a walled-off perforation of the small bowel. Surgical resection was required.

Lymphocyte HVEM/BTLA co-expression after critical illness demonstrates severity indiscriminate upregulation, impacting critical illness-induced immunosuppression

Introduction

The co-regulatory molecule, HVEM, can stimulate or inhibit immune function, but when co-expressed with BTLA, forms an inert complex preventing signaling. Altered HVEM or BTLA expression, separately have been associated with increased nosocomial infections in critical illness. Given that severe injury induces immunosuppression, we hypothesized that varying severity of shock and sepsis in murine models and critically ill patients would induce variable increases in HVEM/BTLA leukocyte co-expression.

Methods

In this study, varying severities of murine models of critical illness were utilized to explore HVEM⁺BTLA⁺ co-expression in the thymic and splenic immune compartments, while circulating blood lymphocytes from critically ill patients were also assessed for HVEM⁺BTLA⁺ co-expression.

Results

Higher severity murine models resulted in minimal change in HVEM⁺BTLA⁺ co-expression, while the lower severity model demonstrated increased HVEM⁺BTLA⁺ co-expression on thymic and splenic CD4⁺ lymphocytes and splenic B220⁺ lymphocytes at the 48-hour time point. Patients demonstrated increased co-expression of HVEM⁺BTLA⁺ on CD3⁺ lymphocytes compared to controls, as well as CD3⁺Ki67^- lymphocytes. Both L-CLP 48hr mice and critically ill patients demonstrated significant increases in TNF-α.

Discussion

While HVEM increased on leukocytes after critical illness in mice and patients, changes in co-expression did not relate to degree of injury severity of murine model. Rather, co-expression increases were seen at later time points in lower severity models, suggesting this mechanism evolves temporally. Increased co-expression on CD3⁺ lymphocytes in patients on non-proliferating cells, and associated TNF-α level increases, suggest post-critical illness co-expression does associate with developing immune suppression.

Management of Acute Appendicitis in HIV/AIDs Patients: A 19-year Review from the National In-Patient Sample

BACKGROUND

Acute Appendicitis (AA), one of the most common surgical emergencies, is usually managed operatively. There is a paucity of data addressing how HIV/AIDS affects management of acute uncomplicated appendicitis.

METHODS

A retrospective review of HIV/AIDS positive (HPos) versus negative (HNeg) patients with acute, uncomplicated appendicitis over a 19-year period. The primary outcome was undergoing appendectomy.

RESULTS

Among 912,779 AA patients, 4,291 patients were HPos. HIV rates increased from 3.8/1,000 in 2000 to 6.3 per 1,000 appendicitis cases in 2019 (p<0.001). HPos patients were older, less likely to have private insurance, and more likely to have psychiatric illnesses, hypertension, and a history of prior malignancy. HPos AA patients underwent operative intervention less often than HNeg AA patients (90.7% versus 97.7%;p<0.001). Overall, comparing HPos to HNeg patients, there was no difference in post-operative infections or mortality.

CONCLUSION

HIV-positive status should not deter surgeons from offering definitive care for acute uncomplicated appendicitis.

Disparities in Decompressive Cranial Surgery Utilization in Severe Traumatic Brain Injury Patients without a Primary Extra-Axial Hematoma: A U.S. Nationwide Study

OBJECTIVE

Decompressive craniectomy is recommended to reduce mortality in severe traumatic brain injury (TBI). Disparities exist in TBI treatment outcomes; however, data on disparities pertaining to decompressive craniectomy utilization is lacking. We investigated these disparities, focusing on race, insurance, sex, and age.

METHODS

Hospitalizations (2004-2014) were retrospectively extracted from the Nationwide Inpatient Sample. The criteria included are as follows: age ≥18 years and indicators of severe TBI diagnosis. Poor outcomes were defined as discharge to institutional care and death. Multivariable logistic regression models were used to assess the effects of race, insurance, age, and sex, on craniectomy utilization and outcomes.

RESULTS

Of 349,164 hospitalized patients, 6.8% (n = 23,743) underwent craniectomy. White (odds ratio [OR] = 0.50, 95% confidence interval [CI] = 0.44-0.57; P < 0.001) and Black (OR = 0.45, 95% CI = 0.32-0.64; P = 0.003) Medicare beneficiaries were less likely to undergo craniectomy. Medicare (P < 0.0001) and Medicaid beneficiaries (P < 0.0001) of all race categories had poorer outcomes than privately insured White patients. Black (OR = 1.2, 95% CI = 1.08-2.34; P = 0.001) patients with private insurance and Black (OR = 1.39, 95% CI = 1.22-1.58; P < 0.0001) Medicaid beneficiaries had poorer outcomes than privately insured White patients (P < 0.0001). Older patients (OR = 0.74, 95%, CI = 0.71-0.76; P < 0.001) were less likely to undergo craniectomy and were more likely to have poorer outcomes. Females (OR = 0.82, 95% CI = 0.76-0.88; P < 0.001) were less likely to undergo craniectomy.

CONCLUSIONS

There are disparities in race, insurance status, sex, and age in craniectomy utilization and outcome. This data highlights the necessity to appropriately address these disparities, especially race and sex, and actively incorporate these factors in clinical trial design and enrollment.

The association between household and neighborhood characteristics and COVID-19 related ICU admissions

Introduction

Approaches to COVID-19 mitigation can be more efficiently delivered with a more detailed understanding of where the severe cases occur. Our objective was to assess which demographic, housing and neighborhood characteristics were independently and collectively associated with differing rates of severe COVID-19.

Methods

A cohort of patients with SARS-CoV-2 in a single health system from March 1, 2020 to February 15, 2021 was reviewed to determine whether demographic, housing, or neighborhood characteristics are associated with higher rates of severe COVID-19 infections and to create a novel scoring index. Characteristics included proportion of multifamily homes, essential workers, and ages of the homes within neighborhoods.

Results

There were 735 COVID-19 ICU admissions in the study interval which accounted for 61 percent of the state's ICU admissions for COVID-19. Compared to the general population of the state those admitted to the ICU with COVID-19 were disproportionately older, male sex, and were more often Black, Indigenous, People of Color. Patients disproportionately resided in neighborhoods with three plus unit multifamily homes, homes built before 1940, homes with more than one person to a room, homes of lower average value, and in neighborhoods with a greater proportion of essential workers. From this our COVID-19 Neighborhood Index value was comparatively higher for the ICU patients (61.1) relative to the population of Rhode Island (49.4).

Conclusion

COVID-19-related ICU admissions are highly related to demographic, housing and neighborhood-level factors. This may guide more nuanced and targeted vaccine distribution plans and public health measures for future pandemics.

Comparison of Infectious Complications after Surgical Fixation versus Epidural Analgesia for Acute Rib Fractures

Background: Surgical stabilization of rib fractures (SSRF) is associated with decreased mortality and respiratory complications. Patients who are not offered SSRF are often treated with epidural analgesia (EA) to reduce pain and improve pulmonary mechanics. We sought to compare infectious complications in patients undergoing either SSRF or EA. We hypothesized that infectious complications are equivalent between the two treatment groups. Patients and Methods: We performed a retrospective cohort study of adult trauma patients with acute rib fractures within the Trauma Quality Improvement Program (TQIP) 2017 dataset and used International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes to identify patients who underwent SSRF or EA. We excluded patients who received both treatments in the same admission. Our primary outcome was the development of sepsis. Secondary outcomes were specific infections including ventilator-associated pneumonia (VAP), catheter-associated urinary tract infection (CAUTI), and central line-associated blood stream infections (CLABSI). Multiple logistic regression analyses were used to adjust for age, injury severity score (ISS), chest Abbreviated Injury Scale (AIS), flail chest, traumatic brain injury (TBI), and comorbidities. Results: We identified 2,252 and 1,299 patients who underwent SSRF and EA, respectively. Patients with SSRF were younger with higher ISS and longer length of stay (LOS). There was no difference in mortality, however, SSRF had higher rate of sepsis (1.6% vs. 0.5%; p = 0.001), VAP (5.1% vs. 0.9%; p < 0.001), CAUTI (1.7% vs. 0.5%; p = 0.001), and CLABSI (0.2% vs. 0%; p = 0.05). On multiple regression, SSRF was associated with higher odds of sepsis (odds ratio [OR], 2.63; 95% confidence interval [CI], 1.04-6.63), CAUTI (OR, 2.96; 95% CI, 1.11-7.88), and VAP (OR, 3.24; 95% CI, 1.73-6.06). Among those who developed sepsis, there was no significant difference in mortality or LOS between groups. Conclusions: Despite no difference in mortality, SSRF was associated with increased risk of septic complications in patients with rib fractures compared to epidural analgesia. Identifying, and addressing, risk factors of sepsis in this patient population is a critical performance improvement process to optimize outcomes without increased adverse events.

Machine learning methods to predict presence of residual cancer following hysterectomy

Surgical management for gynecologic malignancies often involves hysterectomy, often constituting the most common gynecologic surgery worldwide. Despite maximal surgical and medical care, gynecologic malignancies have a high rate of recurrence following surgery. Current machine learning models use advanced pathology data that is often inaccessible within low-resource settings and are specific to singular cancer types. There is currently a need for machine learning models to predict non-clinically evident residual disease using only clinically available health data. Here we developed and tested multiple machine learning models to assess the risk of residual disease post-hysterectomy based on clinical and operative parameters. Data from 3656 hysterectomy patients from the NSQIP dataset over 14 years were used to develop models with a training set of 2925 patients and a validation set of 731 patients. Our models revealed the top postoperative predictors of residual disease were the initial presence of gross abdominal disease on the diaphragm, disease located on the bowel mesentery, located on the bowel serosa, and disease located within the adjacent pelvis prior to resection. There were no statistically significant differences in performances of the top three models. Extreme gradient Boosting, Random Forest, and Logistic Regression models had comparable AUC ROC (0.90) and accuracy metrics (87–88%). Using these models, physicians can identify gynecologic cancer patients post-hysterectomy that may benefit from additional treatment. For patients at high risk for disease recurrence despite adequate surgical intervention, machine learning models may lay the basis for potential prospective trials with prophylactic/adjuvant therapy for non-clinically evident residual disease, particularly in under-resourced settings.

A Case of Recurrent Malignant Melanoma of the Left Foot with In-Transit Metastases

We report a 73-year-old male with recurrent amelanotic malignant melanoma of the left foot with in-transit metastases to the left thigh. In-transit metastatic melanoma can often represent a diagnostic and therapeutic challenge for physicians. This patient was treated with talimogene laherparepvec injections (T-VEC; Imlygic) in the left inguinal and the left plantar region every two weeks for one year as oncolytic viral therapy for advanced non- operable malignant melanoma. He then received consistent follow-up including blood work and PET scans every four months, and he also required further lymph node surgical dissection. To date, our patient has survived 3 years and 11 months, which is 27 months longer than the esti- mated median survival of 1 year 8 months for patients diagnosed with in-transit metastatic melanoma.

Adding Infectious Insult to Traumatic Injury: The Impact of Infectious Complications in End-of-Life Decision Making

Background: Trauma increases the risk for infection, but it is unknown how infection affects goals-of-care (GOC) decision making. We sought to determine how infections impact transition to comfort measures only (CMO), hypothesizing that infectious complications would expedite withdrawal of life-sustaining treatment (WOLST). Patients and Methods: We performed a retrospective review at a level-one trauma center over two years for adult patients without pre-existing advance directives who were made CMO with length of stay longer than one day. Demographics, injuries, and hospital course including infections and the GOC timeline were collected. Patients were divided on the basis of infection development, defined as an infectious complication requiring antibiotics or more invasive intervention, with subgroup analysis comparing those with single versus multiple infections. The primary end point was time to death or discharge. Results: Two hundred thirty-two patients met inclusion criteria and 72 developed an infection. Pneumonia was the most common infection (53.8%). Although those in the infection group had no substantial difference in demographics or comorbidities, they had higher emergency department Glasgow Coma Scale (GCS; 14 vs. 13), lower rate of head injury (28.6 vs. 49%), and higher time to death or discharge (12 vs. 2 days). Goals-of-care discussions were initiated later based on time to first family meeting (7 vs. 1 days), most occurring after the first infection. Subsequent analysis showed that versus those with a single infection (n = 38), those with multiple infections (n = 34) had a higher time to death or discharge (16.5 vs. 10.5 days) despite no difference in demographics, comorbidities, or trauma severity. Time to first family meeting was longer (8.5 vs. 4.5 days) with most occurring after the first infection. Conclusions: We did not find that development of an infection shortens time to WOLST. The increased time to death or discharge in the setting of multiple infections and similar patient populations may be a marker of provider approach to GOC plus family beliefs. Infectious complications play an uncertain role in end-of-life discussions after trauma.

Survival and Pulmonary Injury After Neonatal Sepsis: PD1/PDL1's Contributions to Mouse and Human Immunopathology

Morbidity and mortality associated with neonatal sepsis remains a healthcare crisis. PD1-/- neonatal mice endured experimental sepsis, in the form of cecal slurry (CS), and showed improved rates of survival compared to wildtype (WT) counterparts. End-organ injury, particularly of the lung, contributes to the devastation set forth by neonatal sepsis. PDL1-/- neonatal mice, in contrast to PD1-/- neonatal mice did not have a significant improvement in survival after CS. Because of this, we focused subsequent studies on the impact of PD1 gene deficiency on lung injury. Here, we observed that at 24 h post-CS (but not at 4 or 12 h) there was a marked increase in pulmonary edema (PE), neutrophil influx, myeloperoxidase (MPO) levels, and cytokine expression sham (Sh) WT mice. Regarding pulmonary endothelial cell (EC) adhesion molecule expression, we observed that Zona occludens-1 (ZO-1) within the cell shifted from a membranous location to a peri-nuclear location after CS in WT murine cultured ECs at 24hrs, but remained membranous among PD1-/- lungs. To expand the scope of this inquiry, we investigated human neonatal lung tissue. We observed that the lungs of human newborns exposed to intrauterine infection had significantly higher numbers of PD1+ cells compared to specimens who died from non-infectious causes. Together, these data suggest that PD1/PDL1, a pathway typically thought to govern adaptive immune processes in adult animals, can modulate the largely innate neonatal pulmonary immune response to experimental septic insult. The potential future significance of this area of study includes that PD1/PDL1 checkpoint proteins may be viable therapeutic targets in the septic neonate.

Emerging therapeutic targets for sepsis

Introduction: Sepsis is characterized by a dysregulated host response to infection. Sepsis-associated morbidity/mortality demands concerted research efforts toward therapeutic interventions which are reliable, broadly effective, and etiologically based. More intensive and extensive investigations on alterations in cellular signaling pathways, gene targeting as a means of modifying the characteristic hyper and/or hypo-immune responses, prevention through optimization of the microbiome, and the molecular pathways underlying the septic immune response could improve outcomes.] Areas covered: The authors discuss key experimental mammalian models and clinical trials. They provide an evaluation of evolving therapeutics in sepsis and how they have built upon past and current treatments. Relevant literature was derived from a PubMed search spanning 1987-2020.Expert opinion: Given the complex nature of sepsis and the elicited immune response, it is not surprising that a single cure-all therapeutic intervention, which is capable of effectively and reliably improving patient outcomes has failed to emerge. Innovative approaches seek to address not only the disease process but modify underlying patient factors. A true improvement in sepsis-associated morbidity/mortality will require a combination of unique therapeutic modalities.

Surgical Infection Society Guidance for Restoration of Surgical Services during the Coronavirus Disease-2019 Pandemic

Background: As the coronavirus disease-2019 (COVID-19) pandemic continues globally, high numbers of new infections are developing nationwide, particularly in the U.S. Midwest and along both the Atlantic and Pacific coasts. The need to accommodate growing numbers of hospitalized patients has led facilities in affected areas to suspend anew or curtail normal hospital activities, including elective surgery, even as earlier-affected areas normalized surgical services. Backlogged surgical cases now number in the tens of millions globally. Facilities will be hard-pressed to address these backlogs, even absent the recrudescence of COVID-19. This document provides guidance for the safe and effective resumption of surgical services as circumstances permit. Methods: Review and synthesis of pertinent international peer-reviewed literature, with integration of expert opinion. Results: The "second-wave" of serious infections is placing the healthcare system under renewed stress. Surgical teams likely will encounter persons harboring the virus, whether symptomatic or not. Continued vigilance and protection of patients and staff remain paramount. Reviewed are the impact of COVID-19 on the surgical workforce, considerations for operating on a COVID-19 patient and the outcomes of such operations, the size and nature of the surgical backlog, and the logistics of resumption, including organizational considerations, patient and staff safety, preparation of the surgical candidate, and the role of enhanced recovery programs to reduce morbidity, length of stay, and cost by rational, equitable resource utilization. Conclusions: Resumption of surgical services requires institutional commitment (including teams of surgeons, anesthesiologists, nurses, pharmacists, therapists, dieticians, and administrators). Structured protocols and equitable implementation programs, and iterative audit, planning, and integration will improve outcomes, enhance safety, preserve resources, and reduce cost, all of which will contribute to safe and successful reduction of the surgical backlog.

Unmasking Unique Immune Altering Aspects of the Microbiome as a Tool to Correct Sepsis-Induced Immune Dysfunction

Background: Sepsis-related mortality is driven by immune dysfunction. A bidirectional micro-organism-immune cell cross talks exists. Gut Bacteroides fragilis-T-cell crosstalk maintains innate immune cell/pathogen homeostasis. Commensal gut Clostridia spp. suppress inflammation and induce gut tolerance. Probiotics are administered to restore immune microbiome homeostasis. Individual microbial components have an immunomodulatory effect. However, probiotic therapies for sepsis-induced immune disruptions are rarely tailored to specific immune responses. Thus, we ask the question as to how components of the intestinal microbiome, often found in probiotic therapies, affect lymphocyte phenotypic profile? Methods: T-lymphocytes were cultured with either monomicrobial or polymicrobial combinations. Microbes used were Bacteroides fragilis, Clostridium perfringens, or Lactobacillus acidophilus. Cytokines, measured by enzyme-linked immunosorbent assay (ELISA)-included interleukin (IL)-6, IL-10, IL-22, and IL-33. Flow cytometry was used for T-cell phenotyping for program-death receptor-1 (PD-1) and B- and T-lymphocyte attenuator (BTLA). T-cell DNA was extracted to assess global epigenetic changes. For translation, IL-33 was measured from surgical intensive care unit (ICU) patients with sepsis with either monomicrobial or polymicrobial infection. Results: Lactobacillus consistently induced IL-22 and IL-33. Bacteroides fragilis induced IL-33 only under polymicrobial (pB) conditions. Within surgical ICU patients, IL-33 levels were higher in polymicrobial versus monomicrobial patients. PD-1⁺ expression was lowest with either monomicrobial Bacteroides fragilis or Bacteroides fragilis predominant polymicrobial context. Conversely Bacteroides fragilis exposure induced a distinct PD-1^-high subpopulation. B- and T-lymphocyte attenuator-positive expression did not differ after individual microbes. Among polymicrobial conditions, Bacteroides fragilis predominant (pB) and Lactobacillus acidophilus predominant (pL) increased BTLA⁺ expression. DNA methylation was most increased in response to Clostridium perfringens in monomicrobial and in response to Bacteroides fragilis in polymicrobial conditions. Conclusion: Unique microbe/lymphocyte interactions occur. Bacteroides fragilis induced a T-cell phenotype consistent with potential long-term immune recovery. This work begins to discover how varying microbes may induce unique functional and phenotypic T-lymphocyte responses.

Impact of Multi-Drug-Resistant Pneumonia on Outcomes of Critically Ill Trauma Patients

Background: Rates of infections with multi-drug-resistant organisms (MDROs) are increasing among critically ill patients. Among non-surgical patients, MDROs increase directly the risk of adverse secondary events including death. However, similar effects do not appear to occur among surgical patients. Specifically, among critically injured trauma patients, it is unknown whether degree of injury versus the presence of an MDRO increases the risk of death. Methods: This is a retrospective chart review of admitted adult trauma patients. Data included demographics, medical comorbidities, injury severity score, infections, occurrence of pneumonia including microbiology sensitivity profile, hospital course, and outcomes. Results: Patients requiring adminission to the intensive care unit (ICU) were more severely injured with greater degree of thoracic and head trauma and had a greater burden of pre-trauma medical comorbidities. Among those admitted to the ICU, 93 patients developed pneumonia. Patients who developed pneumonia were younger and more severely injured, with higher rates of thoracic and head injuries and higher rates of smoking. Development of pneumonia was associated with worse outcomes. However, among patients with pneumonia, comparing MDRO to pan-sensitive (PanSens) infections, PanSens infection occurred earlier and were more likely associated with pre-trauma smoking status. There was no difference in injury patterns, medical comorbidities, or outcomes. Conclusion: The development of pneumonia among trauma patients reflects degree of injury and underlying medical status. However, development of MDRO versus PanSens pneumonia did not affect trauma-related outcomes further. This information will guide family discussions and critical care decisions better among vulnerable trauma patients.

Check Point Inhibitors and Their Role in Immunosuppression in Sepsis

Checkpoint regulators are a group of membrane-bound receptors or ligands expressed on immune cells to regulate the immune cell response to antigen presentation and other immune stimuli, such as cytokines, chemokines, and complement. In the context of profound immune activation, such as sepsis, the immune system can be rendered anergic by these receptors to prevent excessive inflammation and tissue damage. If this septic immunosuppression is prolonged, the host is unable to mount the appropriate immune response to a secondary insult or infection. This article describes the manner in which major regulators in the B7-CD28 family and their ligands mediate immunosuppression in sepsis.

Herpes Virus Entry Mediator (HVEM): A Novel Potential Mediator of Trauma-Induced Immunosuppression

BACKGROUND

Herpes virus entry mediator (HVEM) is a coinhibitory molecule which can both stimulate and inhibit host immune responses. Altered expression of HVEM and its ligands is associated with increased nosocomial infections in septic patients. We hypothesize critically ill trauma patients will display increased lymphocyte HVEM expression and that such alteration is predictive of infectious events.

MATERIALS AND METHODS

Trauma patients prospectively enrolled from the ICU were compared with healthy controls. Leukocytes were isolated from whole blood, stained for CD3 (lymphocytes) and HVEM, and evaluated by flow cytometry. Charts were reviewed for injuries sustained, APACHE II score, hospital course, and secondary infections.

RESULTS

Trauma patients (n = 31) were older (46.7 ± 2.4 versus 36.8 ± 2.1 y; P = 0.03) than healthy controls (n = 10), but matched for male sex (74% versus 60%; P = 0.4). Trauma patients had higher presenting WBC (13.9 ± 1.3 versus 5.6 ± 0.5 × 106/mL; P = 0.002), lower percentage of CD3+ lymphocytes (7.5% ± 0.8 versus 22.5% ± 0.9; P < 0.001), but significantly greater expression of HVEM+/CD3+ lymphocytes (89.6% ± 1.46 versus 67.3% ± 1.7; P < 0.001). Among trauma patients, secondary infection during the hospitalization was associated with higher APACHE II scores (20.6 ± 1.6 versus 13.6 ± 1.4; P = 0.03) and markedly lower CD3+ lymphocyte HVEM expression (75% ± 2.6 versus 93% ± 0.7; P < 0.01).

CONCLUSIONS

HVEM expression on CD3+ cells increases after trauma. Patients developing secondary infections have less circulating HVEM+CD3+. This implies HVEM signaling in lymphocytes plays a role in maintaining host defense to infection in after trauma. HVEM expression may represent a marker of infectious risk as well as a potential therapeutic target, modulating immune responses to trauma.

Wandering spleen in a geriatric patient - a rare presentation of gastric volvulus

We report atypical gastric outlet obstruction in a geriatric patient caused by acute mesenteroaxial gastric volvulus precipitated by a wandering spleen.

Influenza and the Surgeon

BACKGROUND

The influenza virus is a pathogenic virus responsible for large numbers of deaths and long-term disabilities worldwide. Although the very young, the very old, and immunocompromised individuals are most susceptible, the effects of the influenza virus can be observed across the entire spectrum of individuals.

DISCUSSION

Infection with the influenza virus induces a substantial inflammatory and immunologic response and induces marked pulmonary inflammation. Many aspects of influenza affect surgical patients directly. Vaccines are one of the most effective measures aimed at reducing the prevalence and severity of many infectious diseases, including the influenza virus. Vaccination programs remain one of the highest priorities across the spectrum of countries, research institutions such as the National Institutes of Health, international health agencies such as the World Health Organization (WHO), and major non-profit organizations.

CONCLUSION

This review addresses aspects of the immune and inflammatory response to influenza, with a focus on the elderly population and healthcare providers who may act as reservoirs for virus transmission to the vulnerable surgical population.

A Case of Severe Lumbar Necrotizing Soft Tissue Infection from an Ileal Pouch Fistula

BACKGROUND

Necrotizing soft tissue infection (NSTI) is a rapidly progressive infection characterized by tissue necrosis, septic shock, and is associated with a high risk of death. Key aspects of successful treatment include early recognition and emergent surgical source control. Necrotizing soft tissue infection may occur from a range of etiologies but may also occur rarely from gastrointestinal routes. We report a case of severe lumbar NSTI arising from an ileal pouch fistula in a patient with inflammatory bowel disease. We report a case of a 62-year-old male with a history of ulcerative colitis and restorative proctocolectomy who presented with a severe NSTI of the lumbar region.

METHODS

Our operative approach focused on debridement of infected necrotic tissue and abscess drainage to achieve source control. We elected to forego a transabdominal approach during the initial operation given that source control but not source elimination was deemed the initial priority.

RESULTS

The patient subsequently underwent a diverting ileostomy and pouch salvage. After a prolonged hospital course, the patient recovered well.

CONCLUSIONS

Fistulization from the gastrointestinal tract is a rare but potential source of NSTI. It is not necessary to address the fistula during the initial operation but should be done promptly after the patient stabilizes. Prompt surgical debridement of infected soft tissue as source control remains the cornerstone of the index operation.

Group 2 Innate Lymphoid Cells (ILC2s) Are Key Mediators of the Inflammatory Response in Polymicrobial Sepsis

Sepsis remains a major public health concern, characterized by marked immune dysfunction. Innate lymphoid cells develop from a common lymphoid precursor but have a role in orchestrating inflammation during innate response to infection. Here, we investigate the pathologic contribution of the group 2 innate lymphoid cells (ILC2s) in a murine model of acute septic shock (cecal ligation and puncture). Flow cytometric data revealed that ILC2s increase in number and percentage in the small intestine and in the peritoneal cells and inversely decline in the liver at 24 hours after septic insult. Sepsis also resulted in changes in ILC2 effector cytokine (IL-13) and activating cytokine (IL-33) in the plasma of mice and human patients in septic shock. Of interest, the sepsis-induced changes in cytokines were abrogated in mice deficient in functionally invariant natural killer T cells. Mice deficient in IL-13-producing cells, including ILC2s, had a survival advantage after sepsis along with decreased morphologic evidence of tissue injury and reduced IL-10 levels in the peritoneal fluid. Administration of a suppressor of tumorigenicity 2 (IL-33R) receptor-blocking antibody led to a transient survival advantage. Taken together, these findings suggest that ILC2s may play an unappreciated role in mediating the inflammatory response in both mice and humans; further, modulating ILC2 response in vivo may allow development of immunomodulatory strategies directed against sepsis.

Changes in the process of alternative RNA splicing results in soluble B and T lymphocyte attenuator with biological and clinical implications in critical illness

Background

Critically ill patients with sepsis and acute respiratory distress syndrome have severely altered physiology and immune system modifications. RNA splicing is a basic molecular mechanism influenced by physiologic alterations. Immune checkpoint inhibitors, such as B and T Lymphocyte Attenuator (BTLA) have previously been shown to influence outcomes in critical illness. We hypothesize altered physiology in critical illness results in alternative RNA splicing of the immune checkpoint protein, BTLA, resulting in a soluble form with biologic and clinical significance.

Methods

Samples were collected from critically ill humans and mice. Levels soluble BTLA (sBTLA) were measured. Ex vivo experiments assessing for cellular proliferation and cytokine production were done using splenocytes from critically ill mice cultured with sBTLA. Deep RNA sequencing was done to look for alternative splicing of BTLA. sBTLA levels were fitted to models to predict sepsis diagnosis.

Results

sBTLA is increased in the blood of critically ill humans and mice and can predict a sepsis diagnosis on hospital day 0 in humans. Alternative RNA splicing results in a premature stop codon that results in the soluble form. sBTLA has a clinically relevant impact as splenocytes from mice with critical illness cultured with soluble BTLA have increased cellular proliferation.

Conclusion

sBTLA is produced as a result of alternative RNA splicing. This isoform of BTLA has biological significance through changes in cellular proliferation and can predict the diagnosis of sepsis.

Outcomes in nursing home patients with traumatic brain injury

BACKGROUND

Traumatic brain injury is a leading cause of death and disability in the United States. In survivors, traumatic brain injury remains a leading contributor to long-term disability and results in many patients being admitted to skilled nursing facilities for postacute care. Despite this very large population of traumatic brain injury patients, very little is known about the long-term outcomes of traumatic brain injury survivors, including rates of discharge to home or risk of death in long-term nursing facilities. We hypothesized that patient demographics and functional status influence outcomes of patients with traumatic brain injury admitted to skilled nursing facilities.

METHODS

We conducted a retrospective cohort study of Medicare fee-for-service beneficiaries aged 65 and older discharged alive and directly from hospital to a skilled nursing facility between 2011 and 2014 using the prospectively maintained Federal Minimum Data Set combined with Medicare claims data and the Centers for Medicare and Medicaid Services Vital Status files. Records were reviewed for demographic and clinical characteristics at admission to the skilled nursing facility, including age, sex, cognitive function, ability to communicate, and motor function. Activities of daily living were reassessed at discharge to calculate functional improvement. We used robust Poisson regression with skilled nursing facility fixed effects to calculate relative risks and 99% confidence intervals for mortality and functional improvement associated with the demographic and clinical characteristics present at admission. Linear regression was used to calculate adjusted mean duration of stay.

RESULTS

Overall, 87,292 Medicare fee-for-service beneficiaries with traumatic brain injury were admitted to skilled nursing facilities. The mean age was 84 years, with 74% of patients older than age 80. Generally, older age, male sex, and poor cognitive or functional status at admission to a skilled nursing facility were associated with increased risk for poorer outcomes. Older patients (age ≥80 years) with traumatic brain injury had a 1.5 times greater risk of death within 30 days of admission compared with adults younger than 80 years (relative risk = 1.49, 99% confidence interval = 1.36, 1.64). Women were 37% less likely to die than men were (relative risk = 0.63, 99% confidence interval = 0.59, 0.68). The risk of death was greater for patients with poor cognitive function (relative risk = 2.55, 99% confidence interval = 2.32, 2.77), substantial motor impairment (relative risk = 2.44, 99% confidence interval = 2.16, 2.77), and patients with impairment in communication (relative risk = 2.58, 99% confidence interval = 2.32, 2.86) compared with those without the respective deficits. One year after admission, these risk factors continued to confer excess risk for mortality. Duration of stay was somewhat greater for older patients (30.1 compared with 27.5 average days) and patients with cognitive impairment (31.7 vs 27.5 average days). At discharge, patients with cognitive impairment (relative risk = 0.86, 99% confidence interval = 0.83, 0.88) and impairment in the ability to communicate (relative risk = 0.67, 99% confidence interval = 0.54, 0.82) were less likely to improve in physical function.

CONCLUSION

Our results suggest that among patients with traumatic brain injury admitted to skilled nursing facilities, the likelihood of adverse outcomes varies significantly by key demographic and clinical characteristics. These findings may facilitate setting expectations among patients and families as well as providers when these patients are admitted to skilled nursing facilities for rehabilitation after their acute episode.

Leukadherin-1 ameliorates endothelial barrier damage mediated by neutrophils from critically ill patients

Background

Multi-organ failure occurs during critical illness and is mediated in part by destructive neutrophil-to-endothelial interactions. The β2 integrin receptor, CR3 (complement receptor 3; Mac-1; CD11b/CD18), which binds endothelial intercellular adhesion molecule-1 (ICAM-1), plays a key role in promoting the adhesion of activated neutrophils to inflamed endothelia which, when prolonged and excessive, can cause vascular damage. Leukadherin-1 (LA-1) is a small molecule allosteric activator of CR3 and has been shown to promote adhesion of blood neutrophils to inflamed endothelium and restrict tissue infiltration. Therefore, LA-1 offers a novel mechanism of anti-inflammatory action by activation, rather than inhibition, of the neutrophil CR3 integrin. However, whether promotion of neutrophil-to-endothelial interaction by this novel therapeutic is of benefit or detriment to endothelial barrier function is not known.

Methods

Critically ill septic and trauma patients were prospectively enrolled from the surgical and the trauma ICU. Blood was collected from these patients and healthy volunteers. Neutrophils were isolated by dextran sedimentation and adhered to TNF-α (tumor necrosis factor-α)-activated human umbilical vein endothelial (HUVEC) monolayers in the presence or absence of fMLP (formylmethionine-leucine-phenylalanine) and/or LA-1. Electric cell-substrate impedance sensing (ECIS) and exposure of underlying collagen were used to quantify endothelial barrier function and permeability.

Results

Neutrophils from critically ill trauma and septic patients caused similar degrees of endothelial barrier disruption which exceeded that caused by cells obtained from healthy controls both kinetically and quantitatively. LA-1 protected barrier function in the absence and presence of fMLP which served as a secondary stimulant to cause maximal loss of barrier function. LA-1 protection was also observed by quantifying collagen exposure underlying endothelial cells challenged with fMLP-stimulated neutrophils. LA-1 treatment resulted in decreased migration dynamics of neutrophils crawling on an endothelial monolayer with reduced speed (μm/s = 0.25 ± 0.01 vs. 0.06 ± 0.01, p < 0.05), path length (μm = 199.5 ± 14.3 vs. 42.1 ± 13.0, p < 0.05), and displacement (μm = 65.2 ± 4.7 vs. 10.4 ± 1.3; p < 0.05).

Conclusion

Neutrophils from patients with trauma or sepsis cause endothelial barrier disruption to a similar extent relative to each other. The CR3 agonist LA-1 protects endothelial barrier function from damage caused by neutrophils obtained from both populations of critically ill patients even when exposed to secondary stimulation.

A Randomized Controlled Trial of Video Education versus Skill Demonstration: Which Is More Effective in Teaching Sterile Surgical Technique?

BACKGROUND

Video education has many advantages over traditional education including efficiency, convenience, and individualized learning. Learning sterile surgical technique (SST) is imperative for medical students, because proper technique helps prevent surgical site infections (SSIs). We hypothesize that video education is at least as effective as traditional skill demonstration in teaching first-year medical students SST.

METHODS

A video series was created to demonstrate SST ( https://www.youtube.com/playlist?list=PLcRU-gvOmxE2mwMWkowouBkxGXkLZ8Uis ). A randomized controlled trial was designed to assess which education method best teaches SST: video education or skill demonstration. First-year medical students (n = 129) were consented and randomly assigned into two groups: those who attended a skill demonstration (control group; n = 70) and those who watched the video series (experimental group; n = 59). The control group attended a pre-existing 90-minute nurse educator-led skill demonstration. Participants then completed a 30-item multiple choice quiz to test their knowledge. Each group then received the alternate education method and completed a 23-item follow-up survey to determine their preferred method.

RESULTS

Seven 2- to 6-minute videos (30 minutes total) were created on surgical attire, scrubbing, gowning and gloving, and maintaining sterility. The experimental group (n = 51) scored higher on the quiz compared with the control group (n = 63) (88% ± 1% versus 72% ± 1%; p < 0.0001). Students preferred the videos when it came to convenience, accessibility, efficiency, and review, and preferred the skill demonstration when it came to knowledge retention, preparedness, and ease of completion.

CONCLUSIONS

Video education is superior to traditional skill demonstration in providing medical students with knowledge of SST. Students identified strengths to each method of teaching. Video education can augment medical students' knowledge prior to their operating room experience to ensure that a sterile environment is maintained for patients. The ultimate goal is to reduce SSIs.

A novel role for coinhibitory receptors/checkpoint proteins in the immunopathology of sepsis

Coinhibitory molecules, such as PD-1, CTLA-4, 2B4, and BTLA, are an important new family of mediators in the pathophysiology of severe bacterial and/or fungal infection, as well as the combined insults of shock and sepsis. Further, the expression of these molecules may serve as indicators of the immune status of the septic individual. Using PD-1:PD-L as an example, we discuss in this review how such checkpoint molecules may affect the host response to infection by mediating the balance between effective immune defense and immune-mediated tissue injury. Additionally, we explore how the up-regulation of PD-1 and/or PD-L1 expression on not only adaptive immune cells (e.g., T cells), but also on innate immune cells (e.g., macrophages, monocytes, and neutrophils), as well as nonimmune cells during sepsis and/or shock contributes to functional alterations often with detrimental sequelae.

Program Cell Death Receptor-1-Mediated Invariant Natural Killer T-Cell Control of Peritoneal Macrophage Modulates Survival in Neonatal Sepsis

We have shown that invariant natural killer T (iNKT) cells mediate sepsis-induced end-organ changes and immune responses, including macrophage bacterial phagocytosis, a finding regulated by the check point protein program cell death receptor-1 (PD-1). Furthermore, PD-1 mediates mortality in both adult and neonatal murine sepsis as well as in surgical patients. Given our previous findings, we hypothesize that iNKT cells will also modulate neonatal sepsis survival, and that this effect is regulated in part through PD-1. We utilized a polymicrobial intra-peritoneal cecal slurry (CS) sepsis model in wild type (WT), iNKT^−/− or PD-1^−/− 5–7 day old neonatal pups. Typically, tissues were harvested at 24 h for various bioassays/histology and, in some cases, survival was assessed for up to 7 days. Interestingly, similar to what we recently reported for PD-1^−/− mice following CS, iNKT^−/−-deficient animals exhibit a markedly improved survival vs. WT. Histologically, minor alterations in liver architectural, which were noted in WT pups, were attenuated in both iNKT^−/− and PD-1^−/− pups. Following CS, PECAM-1 expression was unchanged in the WT pups but increased in both iNKT^−/− and PD-1^−/− pups. In WT, following CS the emergence of a Ly6C^low subpopulation was noted among the influxed peritoneal macrophage population. Conversely, within iNKT^−/− pups, there were fewer peritoneal macrophages and a greater percentage of Ly6C^high macrophages. We show not only a key role for iNKT cells in affecting end-organ damage as well as alterations in phagocytes phenotypes in neonatal sepsis but that this iNKT cell mediated effect is driven by the central checkpoint protein PD-1.

Trauma morning report is the ideal environment to teach and evaluate resident communication and sign-outs in the 80 hour work week

BACKGROUND

The 80h work week has raised concerns that complications may increase due to multiple sign-outs or poor communication. Trauma Surgery manages complex trauma and acute care surgical patients with rapidly changing physiology, clinical demands and a large volume of data that must be communicated to render safe, effective patient care. Trauma Morning Report format may offer the ideal situation to study and teach sign-outs and resident communication.

MATERIALS AND METHODS

Surgery Residents were assessed on a 1-5 scale for their ability to communicate to their fellow residents. This consisted of 10 critical points of the presentation, treatment and workup from the previous night's trauma admissions. Scores were grouped into three areas. Each area was scored out of 15. Area 1 consisted of Initial patient presentation. Area 2 consisted of events in the trauma bay. Area 3 assessed clarity of language and ability to communicate to their fellow residents. The residents were assessed for inclusion of pertinent positive and negative findings, as well as overall clarity of communication. In phase 1, residents were unaware of the evaluation process. Phase 2 followed a series of resident education session about effective communication, sign-out techniques and delineation of evaluation criteria. Phase 3 was a resident-blinded phase which evaluated the sustainability of the improvements in resident communication.

RESULTS

50 patient presentations in phase 1, 200 in phase 2, and 50 presentations in phase 3 were evaluated. Comparisons were made between the Phase 1 and Phase 2 evaluations. Area 1 (initial events) improved from 6.18 to 12.4 out of 15 (p<0.0001). Area 2 (events in the trauma bay) improved from 9.78 to 16.53 (p<0.0077). Area 3 (communication and language) improved from 8.36 to 12.22 out of 15 (P<0.001). Phase 2 to Phase 3 evaluations were similar, showing no deterioration of skills.

CONCLUSIONS

Trauma Surgery manages complex surgical patients, with rapidly changing physiologic and clinical demands. Trauma Morning Report, with diverse attendance including surgical attendings and residents in various training years, is the ideal venue for real-time teaching and evaluation of sign-outs and reinforcing good communication skills in residents.

Do Patients with Pre-Existing Psychiatric Illness Have an Increased Risk of Infection after Injury?

BACKGROUND

Trauma remains a leading cause of death and long term-morbidity. We have shown that patients who sustain traumatic injuries are at increased risk for the development of infectious complications. Psychiatric illnesses (PIs) are also noted to occur frequently among the general population. The presence of a PI has been shown to be a risk factor for the development of infections. Despite the prevalence of both traumatic injuries and psychiatric diseases, there are little data relating the impact of PI on the outcome of patients with trauma. We hypothesize that the presence of a PI will be associated with an increased risk of an infection developing after injury.

PATIENTS AND METHODS

This is a five year retrospective chart review of all admitted patients with trauma age 18 years and older. Patients with and without a major psychiatric illness were compared. Demographic data, mechanism of injury and Injury Severity Score (ISS) were reviewed. Co-morbidities included diabetes mellitus, obesity, pre-injury steroid use, and International Classification of Diseases, 9th edition, based psychiatric illness. All infections were diagnosed by microbiologic criteria (urinary tract infection [UTI], ventilator-associated pneumonia) or Centers for Disease Control and Prevention criteria for clinically evident infections (surgical site infection).

RESULTS

Of the 11,147 admitted trauma patients, 14.5% had a pre-injury PI diagnosis. The PI patients were older (61.5 ± 0.5 vs. 54.3; p < 0.001), more often female (56% vs. 39.1%; p < 0.001), and had no difference in blunt mechanism rates (88.4% vs. 89.9%; p = 0.06) or median ISS (9 vs. 9; p = 0.06). There was no difference between PI and non-PI patients in pre-injury diabetes mellitus (13.4% vs. 12.7%; p = 0.4), steroid use (2.5% vs. 1.9%; p = 0.1), but patients with PI were more likely to be obese (15.7% vs. 13.6%; p = 0.03). Patients with PI were more likely to have an infection develop (10.4% vs. 7.5%; p < 0.001). The most common infection in both groups was UTI (6.9% vs. 4.2%; p < 0.001). Compared with non-PI patients, adjusting for age, gender, ISS, diabetes mellitus, and obesity, patients with PI were more likely to have an infection develop (odds ratio 1.3, 95% confidence interval = 1.1-1.5) Conclusions: Patients with an underlying PI are at increased risk of having a UTI after traumatic injury. This study identifies a previously unknown independent risk factor for UTIs in patients with trauma. This stresses the need for increased awareness and attention to this vulnerable population.

Postoperative Infections are Associated with Increased Risk of Cardiac Events in Vascular Patients

BACKGROUND

Despite advances in perioperative care, the rate of cardiac events in vascular patients remains high. We have previously shown that infections in trauma patients are associated with higher rates of subsequent cardiac complications, likely due to the additive effect of a second hit of an infection following the trauma. The aim of this study was to investigate whether there is an association between postoperative infections and subsequent cardiac events in vascular patients.

METHODS

A 5-year retrospective review of demographics, comorbidities, operative interventions, infectious, and cardiac events in all vascular patients who underwent an operative intervention at a single tertiary referral center was performed. In patients with clinical suspicion of myocardial injury, myocardial damage was defined as troponin >0.15 ng/mL and myocardial infarction (MI) as troponin >1 ng/mL. Pneumonia was diagnosed using bronchoalveolar lavage (BAL) and considered positive if BAL fluid culture contained >10,000 colony-forming units (cfu). Urinary tract infection (UTI) was diagnosed if the urine culture contained >100,000 cfu. All other infections were diagnosed by culture data. Regression analysis was performed to assess risk of cardiac events as a function of infections adjusting for age, gender, and comorbidities.

RESULTS

We analyzed 1,835 vascular operative interventions with the mean age of the cohort 65.5 years (65.9% male). The overall infection rate was 13.2%, with UTI being the most common (60.3%). The overall rate of myocardial damage was 8.1% and the rate of MI 3.8%. Rates of both myocardial damage (15.5 vs. 7.7%; P = 0.0015) and MI (7.1 vs. 3.4%; P = 0.018) were significantly higher in patients with infections, compared to those without infections. Adjusting for age, gender, medical comorbidities, open versus endovascular cases as well as statin and steroid use, patients with UTI were more likely to subsequently develop either myocardial damage (odds ratio [OR] = 3.57 [95% confidence interval = 1.51-8.45]) or MI (OR = 4.20 [1.23-14.3]). A similar association was noted between any infections and either myocardial damage (OR = 2.97 [1.32-6.65]) or MI (OR = 4.31 [1.44-12.94]).

CONCLUSIONS

We herein describe an association between postoperative infections, most commonly UTI, and subsequent cardiac events. Efforts should be made to minimize the risk of developing infections to ensure cardioprotection in vascular patients during perioperative period.

Improved survival after induction of sepsis by cecal slurry in PD-1 knockout murine neonates

BACKGROUND

Sepsis and the ensuing immune dysfunction continue to be major contributors to neonatal morbidity and mortality. Neonatal sepsis also is associated with profound immune dysfunction. We have recently identified a role for a family of coinhibitory molecules that are altered in murine sepsis and in critically ill adult patients, which may be a target for development of novel therapies. There is, however, a paucity of data pertaining to the role of coinhibitory checkpoint proteins in the control and modulation of neonatal sepsis.

METHODS

The cecal slurry model consists of harvesting the cecal content of an adult, wild-type, male mouse and combining it with 5% dextrose to create a cecal slurry with a concentration of 80 mg/mL (LD₇₀ at 7 days). Neonatal mice (5-7 days of age) underwent intraperitoneal injection of the cecal slurry or 0.9% saline for the sham procedure. Wild-type (C57BL/6) or PD-1^-/- mice were used; a 7-day survival study was undertaken. Cytometric bead array was used for cytokine expression. Blood and peritoneal fluid was cultured for bacterial burden. Flow cytometry was used to assess the peritoneal cavity cell populations.

RESULTS

There was no mortality after the sham procedure in either wild-type or PD-1^-/- pups. PD-1 markedly affected sepsis survival with significantly improved survival in the PD-1^-/- pups (40% vs 80%; P < .01). This survival improvement was not associated with any difference in bacterial clearance. The bacterial burden was equivalent between wild-type and PD-1^-/- pups at 24 hours after cecal slurry. However, PD-1^-/- pups did display an increased circulating cytokine response to the cecal slurry compared with wild type, with increased expression of IL-6, IL-10, and TNF-α levels. Within the peritoneal cavity, sepsis induced an influx of neutrophils, a finding that was increased in PD-1^-/- pups. Although the T-cell response was unaffected by PD-1, it was noted that cecal slurry induced a loss of peritoneal B cells in WT, while the peritoneal B-cell population was preserved in PD-1^-/- pups.

CONCLUSION

Our data suggest that the checkpoint protein, PD-1, plays an important role in controlling the immune response to sepsis in the neonate, ultimately affecting sepsis-related mortality in this neonatal murine model of sepsis. Akin to adult studies, these data further emphasize the potential therapeutic target for PD-1 across a spectrum of septic patients.

Soluble programmed cell death receptor-1 (sPD-1): a potential biomarker with anti-inflammatory properties in human and experimental acute respiratory distress syndrome (ARDS)

Background

Acute respiratory distress syndrome (ARDS) remains a common organ dysfunction in the critically ill patient. Mechanisms for its development have focused on immune mediated causes, aspects of our understanding are not complete, and we lack biomarkers.

Design, setting, and subjects

Blood and bronchial alveolar lavage fluid (BAL) from humans (n = 10–13) with ARDS and controls (n = 5–10) as well as a murine model of ARDS (n = 5–6) with controls (n = 6–7) were studied.

Methods

ARDS was induced in mice by hemorrhagic shock (day 1) followed by poly-microbial sepsis (day 2). Samples were then collected on the third day after the animals were euthanized. Ex vivo experiments used splenocytes from animals with ARDS cultured with and without soluble programmed death receptor-1 (sPD-1).

Results

Levels of sPD-1 are increased in both the serum (11,429.3 pg/mL(SD 2133.3) vs. 8061.4(SD 4187.8), p = 0.036) and bronchial alveolar lavage (BAL) fluid (6,311.1 pg/mL(SD 3758.0) vs. 90.7 pg/mL(SD 202.8), p = 0.002) of humans with ARDS. Similar results are seen in the serum (9396.1 pg/mL(SD 1546.0) vs. 3464.5 pg/mL(SD 2511.8), p = 0.001) and BAL fluid (2891.7 pg/mL(SD 868.1) vs. 1385.9 pg/mL(SD 927.8), p = 0.012) of mice. sPD-1 levels in murine blood (AUC = 1(1–1), p = 0.006), murine BAL fluid (AUC = 0.905(0.717–1.093), p = 0.015), and human BAL (AUC = 1(1–1), p = 0.001) fluid predicted ARDS. To assess the importance of sPD-1 in ARDS, ex vivo experiments were undertaken. BAL fluid from mice with ARDS dampens the TNF-α production compared to cells cultured with BAL lacking sPD-1 (2.7 pg/mL(SD 3.8) vs. 52.38 pg/mL(SD 25.1), p = 0.002).

Conclusions

This suggests sPD-1 is elevated in critical illness and may represent a potential biomarker for ARDS. In addition, sPD-1 has an anti-inflammatory mechanism in conditions of marked stress and aids in the resolution of severe inflammation. sPD-1 could be used to not only diagnose ARDS, but may be a potential therapy.

Lymphocyte integrin expression differences between SIRS and sepsis patients

BACKGROUND

Systemic Inflammatory Response Syndrome (SIRS) and sepsis remain leading causes of death. Despite many similarities, the two entities are very distinct clinically and immunologically. T-Lymphocytes play a key pivotal role in the pathogenesis and ultimately outcome following both SIRS and sepsis. Integrins are essential in the trafficking and migration of lymphocytes. They also serve vital roles in efficient wound healing and clearance of infections. Here, we investigate whether integrin expression, specifically β1 (CD29) and β2 (CD18), are disrupted in SIRS and sepsis, and assess differences in integrin expression between these two critically ill clinical categories.

METHODS

T-Lymphocytes were isolated from whole blood collected from ICU patients exhibiting SIRS or sepsis. Samples were analyzed for CD18 (β2) and CD29 (β1) on CD3⁺ T cells through flow cytometry. Septic patients were stratified into either exclusively abdominal or non-abdominal sources of sepsis.

RESULTS

CD18 was almost ubiquitously expressed on CD3⁺ T cells irrespective of clinical condition. However, CD29 (β1 integrin) was lowest in SIRS patients (20.4% of CD3⁺ T cells) when compared with either septic patients (35.5%) or healthy volunteers (54.1%). Furthermore, there was evidence of compartmentalization in septic patients, where abdominal sources had a greater percentage of CD3⁺CD29⁺ T cells (41.7%) when compared with those with non-abdominal sources (29.5%).

CONCLUSION

Distinct differences in T-cell integrin expression exists between patients in SIRS versus sepsis, as well as relative to the source of sepsis. Further work is needed to understand cause and effect relative to the progression from SIRS into sepsis.

Trauma patients who present in a delayed fashion: a unique and challenging population

BACKGROUND

A proportion of trauma patients present for evaluation in a delayed fashion after injury, likely due to a variety of medical and nonmedical reasons. There has been little investigation into the characteristics and outcomes of trauma patients who present delayed. We hypothesize that trauma patients who present in a delayed fashion are a unique population at risk of increased trauma-related complications.

MATERIALS AND METHODS

This was a retrospective review from 2010-2015 at a Level I trauma center. Patients were termed delayed if they presented >24 hours after injury. Patients admitted within 24 hours of their injury were the comparison group. Charts were reviewed for demographics, mechanism, comorbidities, complications and outcomes. A subgroup analysis was done on patients who suffered falls.

RESULTS

During the 5-y period, 11,705 patients were admitted. A total of 588 patients (5%) presented >24 h after their injury. Patients in the delayed group were older (65 versus 55 y, P < 0.001) and more likely to have psychiatric comorbidities (33% vs. 24%, P = 0.0001) than the control group. They were also more likely to suffer substance withdrawal (8.9% vs. 4.1%, P < 0.001) but had toxicology testing for drugs and alcohol done at significantly lower rates. Patients that presented delayed after falls were similar in age and injury severity score (ISS) but more likely to suffer substance withdrawal when compared to those with falls that presented within 24 hours. Patients with falls that presented delayed had toxicology testing at significantly lower rates than the comparison group.

CONCLUSIONS

Trauma patients that present to the hospital in a delayed fashion have unique characteristics and are more likely to suffer negative outcomes including substance withdrawal. Future goals will include exploring strategies for early intervention, such as automatic withdrawal monitoring and social work referral for all patients who present in a delayed fashion.

Divergent invariant natural killer T-cell response to sepsis of abdominal vs. non-abdominal origin in human beings

BACKGROUND

The etiology of sepsis is broad. The peritoneal cavity displays compartmentalization with respect to inflammatory responses, so peripheral blood responses to sepsis of abdominal vs. non-abdominal origin are expected to be divergent. Lymphocytes and invariant natural killer T (iNKT) cells play important roles in survival from sepsis, as they dampen the neutrophil and macrophage responses. We assessed whether circulating iNKT cells display distinct phenotypic profiles depending on the presence of abdominal vs. non-abdominal infection with sepsis.

METHODS

Patients with sepsis, defined as infection confirmed microbiologically with a systemic inflammatory response syndrome (SIRS), were enrolled prospectively. They were categorized as having either exclusively sepsis of abdominal or exclusively non-abdominal origin. The white blood cell (WBC) count was recorded. Whole-blood staining with monoclonal antibodies to CD3, V-alpha-24 (to identify iNKT cells), and CD69 (marker of early activation) was applied.

RESULTS

Of the 53 enrolled patients, 18 had abdominal infection. Pneumonia was the most common non-abdominal type. There was no difference in gender, age, Acute Physiology and Chronic Health Evaluation (APACHE) II score, WBC count, or CD3(+) T cells (7.1%±1.6% vs. 6.5%±0.9%; p=0.75) in the two groups. Patients with abdominal infection had a higher proportion of iNKT cells (2.7%±1.1% vs. 0.89%±0.14%; p=0.032). Correcting for WBC count, this translated into a higher absolute number of iNKT cells (3.4±1.8×10(7)/L vs. 0.74±0.15×10(7)/L; p=0.03). Patients with sepsis of abdominal origin had a lower percentage of CD69(+) iNKT cells (9.1%±3.1% vs. 27.2%±5.8%; p=0.028). In patients in shock vs. those who were not, patients with non-abdominal infection exhibited a greater number of iNKT cells (1.47±0.3 v. 0.62±0.1×10(7)/L; p=0.022) and percentage of activated iNKT cells (53±14.5% vs. 17.9±4.8%; p=0.04). Patients with non-abdominal infection who died had a lower absolute number of activated iNKT cells (0.8±1.2×10(7)/L vs. 0.34±0.1×10(7)/L; p=0.023); however, no such shock or death correlation was noted in patients with sepsis of abdominal origin.

CONCLUSIONS

Divergent sepsis etiologies display distinct blood iNKT cell population changes. In non-abdominal infection, this difference was associated with septic shock and death. Elucidating the importance and basis for these changes relative to the response to sources of infection will help clarify appropriate diagnosis and management of the patient with sepsis.

American College of Surgeons National Surgical Quality Improvement Program as a quality-measurement tool for advanced cancer patients

BACKGROUND

Multiple studies have shown the significantly increased post-operative morbidity and mortality of patients undergoing palliative operations. It has been proposed by some authors that the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database can be used reliably to develop risk-calculators or as an aid for clinical decision-making in advanced cancer patients. ACS-NSQIP is a population-based database that by design only captures outcomes data for the first 30-day following an operation. We considered the suitability of these data as a tool for decision-making in the advanced cancer patient.

METHODS

Six-year retrospective review of a single institution's ACS-NSQIP database for cases identified as "Disseminated Cancer". Procedures performed with palliative intent were identified and analyzed.

RESULTS

Of 7,763 patients within the ACS-NSQIP database, 138 (1.8%) were identified as having "Disseminated Cancer". Of the remaining 7,625 entries only 4,486 contained complete survival data for analysis. Thirty-day mortality within the "Disseminated Cancer" group was higher when compared to all other surgical patients (7.9% vs. 0.9%, P<0.001). Explicit chart review of these 138 patients revealed that 32 (23.2%) had undergone operations with palliative intent. Overall survival for palliative and non-palliative operations was significantly different (104 vs. 709 days, P<0.001). When comparing palliative to non-palliative procedures using ACS-NSQIP data, we were unable to detect a difference in 30-day mortality (9.4% vs. 7.5%, P=0.72).

CONCLUSIONS

Calculations utilizing ACS-NSQIP data fail to demonstrate the increased mortality associated with palliative operations. Patients diagnosed with advanced cancer are not adequately represented within the database due to the limited number of cases collected. Also, more suitable outcomes measures for palliative operations such as pain relief, functional status, and quality of life, are not captured. Therefore, the sole use of thirty-day morbidity and mortality data contained in the ACS-NSQIP database is insufficient to make sound decisions for surgical palliation.

The geriatric cytokine response to trauma: time to consider a new threshold

BACKGROUND

Inflammatory responses to trauma, especially if exaggerated, drive mortality and morbidities including infectious complications. Geriatric patients are particularly susceptible to profound inflammation. Age-related declines in inflammatory and immune systems are known to occur. Geriatric patients display dampened inflammatory responses to non-critical disease processes. Specific inflammatory responses in critically ill geriatric trauma patients, and how the inflammatory profile associated with subsequent infections or mortality, remain unknown.

METHODS

Geriatric (≥65 y) and young (18-50 y old) critically ill blunt trauma intensive care unit (ICU) patients were enrolled prospectively. Blood was drawn within 36 h of presentation to measure circulating cytokines including interleukin (IL)-6 (pg/mL), IL-10 (pg/mL), and tumor necrosis factor (TNF)-α (pg/mL) levels. Age, gender, Acute Physiology and Chronic Health Evaluation (APACHE II) score and outcomes were reviewed.

RESULTS

Twenty-one young and 29 geriatric critically ill patients were recruited. Groups were comparable in male gender and age-adjusted APACHE II score, but geriatric patients had higher mortality (38% versus 9.5%; p=0.04). Within geriatric trauma patients, the development of a secondary infection was associated with significantly lower presenting IL-6 and IL-10 levels and no difference in TNF-α levels. Furthermore, geriatric patients who died had elevated IL-6 and IL-10 and decreased TNF-α levels compared with geriatric patients who lived. Compared with the young cohort, IL-6 and IL-10 levels were similar between geriatric patients who died and young patients who lived. However, geriatric patients who lived, compared with young patients who lived, had significantly lower IL-6 and IL-10. There was no such relation noted with TNF-α.

CONCLUSIONS

A lowered inflammatory response in geriatric patients is associated with the development of a subsequent infection. However, geriatric patients exhibiting inflammatory responses as robust as their younger counterparts have increased mortality. Redefining our understanding of an appropriate geriatric inflammatory response to trauma will help future therapy, thereby improving morbidity and mortality.

Advancing technologies for the diagnosis and management of infections

Infections remain a significant problem among surgical patients. Technological advances, especially in the arena of nano-technology, have markedly improved the ability to detect, prevent and treat surgical infections. No longer limited to culture-based methods of pathogen detection or standard antimicrobial therapies, options for management of surgical infections are rapidly expanding. Such advances are critical in this era of rapidly developing resistant and virulent strains of organisms. Further, our understanding of the host pathogen interaction grows exponentially with the development of computer-based modeling, aiding in expediting research endeavors.