Predictive perioperative factors for developing severe sepsis after major surgery

One-Hour Bundle Protocols for Surgical Sepsis and Septic Shock in Surgical Intensive Care Unit: Clinical Outcome Aspects in the Thai Context

BACKGROUND

Surgical sepsis is a syndrome occurring during the perioperative period with a high mortality rate. Since the one-hour bundle protocol was recommended to decrease sepsis-related morbidity and mortality in clinical practice, the protocol has been applied to surgical patients with sepsis and septic shock. However, clinical outcomes in these surgical patients remain unknown. Thus, this study aimed to compare survival outcomes in patients before and after the implementation of one-hour bundle care in clinical practice.

METHODS

In this prospective cohort study, 401 surgical patients with sepsis were divided into two groups, with 195 patients undergoing the one-hour bundle from December 25, 2021, to March 31, 2024, and 206 patients undergoing usual care from January 1, 2018, to December 24, 2021, before the one-hour bundle protocol was implemented by the Surviving Sepsis Campaign (SSC). Demographic data, treatment processes, and clinical outcomes were recorded.

RESULTS

After the one-hour bundle protocol was applied in surgical practice, the median survival time was significantly increased in surgical patients who underwent one-hour bundle care (95% confidence interval (CI): 12.32-19.68) (p= 0.016). Factors influencing the increase in the mortality rate were delays in fluid resuscitation of >2 hours, vasopressor initiation of >2 hours, and empirical antibiotics of >5 hours (p= 0.017, 0.028, and 0.008, respectively).

CONCLUSION

One-hour bundle care for surgical patients with sepsis resulted in an increased median survival time. Delays in fluid resuscitation (>2 hours), vasopressor initiation (>2 hours), and empirical antibiotics (>5 hours) were factors associated with mortality.

Clinical Characteristics and Nomogram for Predicting Mortality in Patients with Postoperative Bloodstream Infection in Surgical Intensive Care Unit

Background

Bloodstream infection is amongst the leading causes of mortality for critical postoperative patients. However, data, especially from developing countries, are scary. Clinical decision-making tools for predicting postoperative bloodstream infection-related mortality are important but still lacking.

Objective

To analyze the distribution of pathogens and develop a nomogram for predicting mortality in patients with postoperative bloodstream infection in the surgical intensive care unit.

Methods

The clinical data, infection and pathogen-related data, and prognosis of patients with PBSI in the SICU from January 2017 to January 2022 were retrospectively collected. The distribution of pathogens and clinical characteristics of patients with PBSI were analyzed. The patients were assigned to a died group and a survived group according to their survival status. Independent predictors for mortality were identified by univariate and multivariate analyses. A nomogram for predicting PBSI-related death was developed based on these independent predictors. Calibration and decision-curve analysis were established to evaluate the nomogram. We collected postoperative patients admitted to our center from February 2022 to June 2023 as external validation sets to verify the nomogram. We also add the Brier score to further validate the model.

Results

In the training set, 7128 patients admitted to the SICU after different types of surgery were collected. A total of 198 patients and 308 pathogens were finally enrolled. The mean age of patients with PBSI was 64.38 ± 16.22 (range 18-90) years, and 56.1% were male. Forty-five patients (22.7%) died in the hospital. Five independent predictors including BMI, APACHE II score, estimated glomerular filtration rate (eGFR), urine volume in the first 24 hours after surgery, and peak temperature before positive blood cultures were selected to establish the nomogram. The area under the receiver operating characteristic curve for the prediction model was 0.922. Calibration curve and decision curve analysis showed good performance of the nomogram. Seventy patients with PBSI were collected as an external validation set, and thirteen patients died in this set. The external validation set was used to validate the nomogram, and the results showed that the AUC was 0.930 which was higher than that in the training set indicating that the nomogram had a good discrimination. The brier score was 0.087 for training set and 0.050 for validation set.

Conclusions

PBSI was one of the key issues that clinicians were concerned and could be assessed with a good predictive model using simple clinical factors.

Identifying Effective Biomarkers for Accurate Pancreatic Cancer Prognosis Using Statistical Machine Learning

Pancreatic cancer (PC) has one of the lowest survival rates among all major types of cancer. Consequently, it is one of the leading causes of mortality worldwide. Serum biomarkers historically correlate well with the early prognosis of post-surgical complications of PC. However, attempts to identify an effective biomarker panel for the successful prognosis of PC were almost non-existent in the current literature. The current study investigated the roles of various serum biomarkers including carbohydrate antigen 19-9 (CA19-9), chemokine (C-X-C motif) ligand 8 (CXCL-8), procalcitonin (PCT), and other relevant clinical data for identifying PC progression, classified into sepsis, recurrence, and other post-surgical complications, among PC patients. The most relevant biochemical and clinical markers for PC prognosis were identified using a random-forest-powered feature elimination method. Using this informative biomarker panel, the selected machine-learning (ML) classification models demonstrated highly accurate results for classifying PC patients into three complication groups on independent test data. The superiority of the combined biomarker panel (Max AUC-ROC = 100%) was further established over using CA19-9 features exclusively (Max AUC-ROC = 75%) for the task of classifying PC progression. This novel study demonstrates the effectiveness of the combined biomarker panel in successfully diagnosing PC progression and other relevant complications among Egyptian PC survivors.

Blood Biomarkers in Patients with Parkinson's Disease: A Review in Context of Anesthetic Care

Parkinson's disease (PD) is the second most common inflammatory neurodegenerative disorder after dementia. Preclinical and epidemiological data strongly suggest that chronic neuroinflammation slowly induces neuronal dysfunction. Activated microglia secrete several neurotoxic substances, such as chemokines and proinflammatory cytokines, which may promote blood-brain barrier (BBB) permeabilization. CD4⁺ T cells comprise proinflammatory cells such as T helper (Th) 1 and Th17 cells, as well as anti-inflammatory cells such as Th2 and T regulatory cells (Tregs). Th1 and Th17 cells can be detrimental to dopamine neurons, whereas Th2 and Tregs are neuroprotective. The results of studies on the serum levels of cytokines such as IFN-γ and TNF-α secreted by Th1 T cells, IL-8 and IL-10 secreted by Th2 T cells, and IL-17 secreted by Th17 cells in PD patients are not uniform. In addition, the relationships between serum cytokine levels and motor and non-motor symptoms of PD are controversial. Surgical stress and anesthesia induce inflammatory responses by disturbing the balance between pro- and anti-inflammatory cytokines, which may exacerbate the neuroinflammatory response in PD patients. Here we review studies on blood inflammatory biomarkers in PD patients and discuss the roles of surgery and anesthesia in PD progression.

Exogenous ketone ester administration attenuates systemic inflammation and reduces organ damage in a lipopolysaccharide model of sepsis

AIMS

Sepsis is a life-threatening condition of organ dysfunction caused by dysregulated inflammation which predisposes patients to developing cardiovascular disease. The ketone β-hydroxybutyrate is reported to be cardioprotective in cardiovascular disease and this may be due to their signaling properties that contribute to reducing inflammation. While exogenous ketone esters (KE) increase blood ketone levels, it remains unknown whether KEs can reduce the enhanced inflammatory response and multi-organ dysfunction that is observed in sepsis. Thus, this study assesses whether a recently developed and clinically safe KE can effectively improve the inflammatory response and organ dysfunction in sepsis.

METHODS AND RESULTS

To assess the anti-inflammatory effects of a KE, we utilized a model of lipopolysaccharide (LPS)-induced sepsis in which an enhanced inflammatory response results in multi-organ dysfunction. Oral administration of KE for three days prior to LPS-injection significantly protected mice against the profound systemic inflammation compared to their vehicle-treated counterparts. In assessing organ dysfunction, KE protected mice from sepsis-induced cardiac dysfunction as well as renal dysfunction and fibrosis. Furthermore, KE administration attenuated the sepsis-induced inflammation in the heart, kidney, and liver. Moreover, these protective effects occurred independent of changes to enzymes involved in ketone metabolism.

CONCLUSION

These data show that the use of an exogenous KE attenuates the dysregulated systemic and organ inflammation as well as organ dysfunction in a model of severe inflammation. We postulate that this exogenous KE is an appealing and promising approach to capitalize on the protective anti-inflammatory effects of ketones in sepsis and/or other inflammatory responses.

A scoring system for the preoperative evaluation of prognosis in spinal infection: the MSI-20 score

BACKGROUND CONTEXT

Spinal infection (SI) is a life-threatening condition and its treatment remains challenging. Recent studies have supported early and aggressive surgery, but mortality still reaches 5% to 10% and it remains unclear, if an aggressive surgical strategy also applies for severely sick patients.

PURPOSE

The aim of this analysis was to generate an assessment score to predict mortality of SI in order to facilitate decision-making.

STUDY DESIGN

Retrospective risk factor analysis.

PATIENT SAMPLE

Two hundred fifty-two patients were retrospectively analyzed.

OUTCOME MEASURES

Physiologic measures, functional measures.

METHODS

Diagnosis was based on clinical presentation, imaging findings and inflammatory markers. Factors associated with mortality were identified by multivariate analysis, weighted according to their relative risk ratio (RR) and included in the novel assessment score.

RESULTS

Eight parameters were included: (1) BMI, (2) ASA score, (3) presence of sepsis, (4) age-adjusted Charlson Comorbidity Index, (5) presence and degree of renal failure, (6) presence of hepatopathy, (7) neurological deficits and (8) CRP levels at diagnosis. Each parameter was assigned a certain range of points, resulting in a maximum total score of 20. The mortality in spinal infection (MSI-20) score - indicating poorer status with higher values - was obtained for each patient and correlated with mortality.

CONCLUSION

An MSI-20 score of 11 or more points seems to identify the small group of patients being "too sick to undergo surgery," while early surgery can be recommended in the remainder (MSI-20 ≤10). Our results need to be confirmed in prospective studies, but may give guidance for indicating surgery even in rather sick and comorbid patients.

Elevated high-sensitivity C-reactive protein concentrations may be associated with increased postdischarge mortality in patients with myocardial injury after noncardiac surgery: A retrospective observational study

BACKGROUND

Myocardial injury after noncardiac surgery (MINS) is one of the most common cardiovascular complications associated with mortality and morbidity during the first 2 years after surgery. However, the relevant variables associated with mortality after discharge in patients with MINS have not been fully investigated.

OBJECTIVES

This study aimed to evaluate the association between persistent inflammation detected by high-sensitivity C-reactive protein (hsCRP) at discharge and postdischarge mortality after MINS.

DESIGN

Retrospective observational analysis of acquired data from Samsung Medical Center Troponin in Noncardiac Operation (SMC-TINCO) registry.

SETTING

A tertiary hospital from January 2010 to June 2019.

PATIENTS

Patients who were discharged alive after a diagnosis of MINS.

MAIN OUTCOME MEASURES

The primary endpoint was postdischarge 1-year mortality, and 30-day mortality and the mortality from 30 days to 1 year was also compared.

RESULTS

Data from a total of 4545 adult patients were divided into two groups according to hsCRP concentration at discharge. There were 757 (16.7%) patients in the normal hsCRP group and 3788 (83.3%) patients in the elevated hsCRP group. After inverse probability weighting, 1-year mortality was significantly higher in the elevated group than the normal group (hazard ratio 1.93, 95% CI 1.45 to 2.57, P  < 0.001). Thirty-day mortality and the mortality from 30 days to 1 year were also increased in the elevated group.

CONCLUSION

In patients with MINS, an elevated hsCRP concentration at discharge appeared to be associated with increased mortality. Further research is needed to determine whether controlling inflammation can be helpful in reducing mortality.

Sepsis after elective surgery - Incidence, aetiology and outcome

BACKGROUND

Sepsis requiring admission to intensive care (ICU) is a rare complication of elective surgery, but is associated with high morbidity and mortality. The aim of this study was to describe the incidence and outcome of sepsis following elective surgery.

METHODS

This was a retrospective, observational study where all admissions to Icelandic ICUs during calendar years 2006, 2008, 2010, 2012, 2014 and 2016 were screened, identifing patients with sepsis following elective surgery (ACCP/SCCM criteria). The number of elective operations performed at the largest center (Landspitali) during the study years were collected. Descriptive statistics were used to assess the incidence and outcome of patients with sepsis after elective surgery.

RESULTS

During the study years, 88 patients were admitted to Icelandic ICUs with sepsis following elective surgery. Of those, 80 were operated at Landspitali, where the incidence of sepsis was 0.19% per elective procedure, highest following pancreaticoduodenectomies (14%, CI 6-25) and esophagectomies (13%, CI 4-27), but the greatest number of patients (30% (26/88)) developed sepsis after a colorectal procedure. The most common infection sources were the abdomen (65% (57/88)) and lungs/mediastinum (22% (19/88)), frequently polymicrobial (58% (36/62) of patients with cultures). The incidence of insufficient empirical antibiotics was high (50% (30/60)). The median ICU and hospital length-of-stay were 5.5 and 26 days and the 28-day and 1-year mortality rates were 16% (14/88) and 41% (36/87), respectively.

CONCLUSIONS

Incidence of sepsis following elective surgery is low in Iceland but mortality is high. Initial antimicrobial therapy needs careful consideration in these hospital-acquired, often polymicrobial infections.

Increased inspired oxygen concentration does not adversely affect oxidative stress and the resolution of inflammation during reperfusion in patients undergoing knee replacement surgery

The level of inspired oxygen during surgery may modify free radical release, and reperfusion injury. This controlled trial examined the effect of inspired oxygen on F₂-isoprostanes (F₂-IsoPs), isofurans (IsoFs), and specialized mediators of inflammation resolution (SPM) during knee replacement surgery. Patients received either 30% O₂ (control n = 21), 50% O₂ (n = 20), or 80% O₂ (n = 19) O₂, in a parallel design. Hemoglobin (Hb) was measured throughout the surgery and F₂-IsoPs, IsoFs and SPM were analyzed by mass spectrometry. The effect of O₂ on F₂-IsoPs and IsoFs was examined during tourniquet inflation and after tourniquet release. SPM were measured at baseline and the end of surgery. There was a significant interaction between O₂ and Hb concentrations with plasma IsoFs during tourniquet inflation. An increase in plasma IsoFs over time was attenuated in the 80% O₂ group (p=.012) compared with the 30% O₂ group after adjusting for Hb concentration. After tourniquet release, plasma F₂-IsoPs were significantly lower in the 50% and 80% O₂ groups (p=.009 and p=.001, respectively) compared with the 30% O₂ group after adjustment for Hb concentration. The SPM RvD2 and RvE2 were increased with 50% and 80% O₂ (RvD2, p=.014 and p=.002, respectively; RvE2, p=.032 with 50% O₂) compared with the 30% O₂ group, in analyses that corrected for Hb concentration. We have shown for the first time that higher O₂ levels may be beneficial in reducing oxidative stress and increasing resolution of inflammation during surgery that involves reperfusion after application of a tourniquet.

Early surgery may lower mortality in patients suffering from severe spinal infection

PURPOSE

Spinal infection (SI) is a life-threatening condition and treatment remains challenging. Numerous factors influence the outcome of SI and both conservative and operative care can be applied. As SI is associated with mortality rates between 2 and 20% even in developed countries, the purpose of the present study was to investigate the occurrence and causes of death in patients suffering from SI.

METHODS

A retrospective analysis was performed on 197 patients, categorized into two groups according to their outcome: D (death) and S (survival). The diagnosis was based on clinical and imaging (MRI) findings. Data collected included demographics, clinical characteristics, comorbidities, infection parameters, treatment details, outcomes, and causes of death.

RESULTS

The number of deaths was significantly higher in the conservative group (n = 9/51, 18%) compared with the operative counterpart (n = 8/146, 6%; p = 0.017). Death caused by septic multiorgan failure was the major cause of fatalities (n = 10/17, 59%) followed by death due to cardiopulmonary reasons (n = 4/17, 24%). The most frequent indication for conservative treatment in patients of group D included "highest perioperative risk" (n = 5/17, 29%).

CONCLUSION

We could demonstrate a significantly higher mortality rate in patients solely receiving conservative treatment. Mortality is associated with number and type of comorbidities, but also tends to be correlated with primarily acquired infection. As causes of death are predominantly associated with a septic patient state or progression of disease, our data may call for an earlier and more aggressive treatment. Nevertheless, prospective clinical trials will be mandatory to better understand the pathogenesis and course of spinal infection, and to develop high quality, evidence-based treatment recommendations.

Sepsis after elective neurosurgery: Incidence, outcomes, and predictive factors

Sepsis is a life-threatening condition resulting from systemic infection, with mortality rates approaching 30%. Most neurological surgeries are now performed electively, which permits medical optimization preoperatively. We performed a retrospective cohort analysis of 122,466 adult elective neurosurgical patients from 2012 to 2018 in the National Surgical Quality Improvement Program database. To select for a medically optimized population, patients were included if they arrived from home on the day of surgery, were not pregnant or puerperium, and had no documented evidence of preexisting infection. We analyzed demographic, comorbidity, and operative information; performed multivariate logistic regression to explore factors predictive of postoperative sepsis; and evaluated outcomes for patients who developed sepsis. Overall, 0.87% of patients developed postoperative sepsis (n = 1,067). The rate of sepsis was higher in the cranial subpopulation (1.21%; n = 330) and lower in the spinal subpopulation (0.77%; n = 733). The overall sepsis cohort was older, had more males, was more functionally dependent, had longer operation durations, and had higher rates of medical comorbidities. Minority race and smoking were not associated with sepsis. The sepsis cohort fared worse than the control cohort across all outcome measures, including prolonged length-of-stay (≥90^th percentile), discharge anywhere but home, 30-day readmission, 30-day reoperation, and 30-day mortality. Results for the cranial and spine subpopulations follow similar trends. In summary, sepsis in the elective neurosurgical population is an uncommon but devastating cause of excess morbidity and mortality.

Risk Factors for Post-Operative Sepsis and Septic Shock in Patients Undergoing Emergency Surgery

Background: Sepsis after emergency surgery is associated with a higher mortality rate than elective surgery, and total hospital costs increase by 2.3 times. This study aimed to identify risk factors for post-operative sepsis or septic shock in patients undergoing emergency surgery. Methods: A retrospective cohort analysis was performed using the National Surgical Quality Improvement Program (NSQIP) by identifying patients undergoing emergency surgery between 2012 and 2015 and comparing those who developed post-operative sepsis or septic shock (S/SS) with those who did not. Patients with pre-operative sepsis or septic shock were excluded. Multiple logistic regression was used to identify risk factors for the development of S/SS in patients undergoing non-elective surgery. Results: Of 122,281 patients who met the inclusion criteria, 2,399 (2%) developed S/SS. Risk factors for S/SS were American Society of Anesthesiologists Physical Status (ASA PS) class 2 or higher (odds ratio [OR] 2.57; 95% confidence interval [CI] 2.19-3.02; p < 0.0001), totally dependent (OR 2.00, 95% CI 1.38-2.83; p = 0.00021) or partially dependent (OR 1.62, 95% CI 1.35-2.00; p < 0.0001) functional status, and male gender (OR 1.31; 95% CI 1.18-1.45; p < 0.0001). Compared with colorectal procedures, patients undergoing pancreatic (OR 2.33, CI 1.40-3.87; p = 0.00108) and small intestine (OR 1.27; CI 1.12-1.44; p = 0.00015) surgery were more likely to develop S/SS. Patients undergoing biliary surgery (OR 0.38; CI 0.30-0.48; p < 0.0001) were less likely to develop S/SS. Conclusions: Risk factors for the development of sepsis or septic shock are ASA PS class 2 or higher, partially or totally dependent functional status, and male gender. Emergency pancreatic or small intestinal procedures may confer a higher risk. Greater vigilance and early post-operative screening may be of benefit in patients with these risk factors.

Role of Perioperative Surgical Safety Checklist in Reducing Morbidity and Mortality among Patients: An Observational Study

Background:

Safe Surgery Saves Lives. Patient safety is a fundamental of good quality health care, and complications due to the health-care system are well-documented and constitute an important public health problem. Implementation of the checklist in medicine and surgery can help to decrease the risk of adverse events thus can improve patient safety.

Materials and Methods:

After the Institutional Ethical Committee clearance, a total of 500 patients were enrolled and divided into two equal groups. In Group 1 (n = 250), patients underwent surgery before regular implementation of the World Health Organization (WHO) surgical safety checklist (SSC), whereas in Group 2 (n = 250), patients underwent surgery after the WHO SSC was regularly implemented. All the patients were followed up after the surgery, and patients were looked for and compared for the postoperative complications.

Results:

We found that 27 patients (10.8%) in Group 1 and 13 patients (5.2%) in Group 2 developed major wound disruption (P < 0.05). There were 73 patients (29.2%) in Group 1 and 34 patients (13.6%) in the Group 2 who developed an infection of the surgical site (P < 0.05). There were five patients (2%) in Group 1 while none of the patients in Group 2 developed sepsis during the study (P < 0.05).

Conclusions:

We found that implementation of the WHO SSC significantly reduces surgical site infections, major disruptions of the wound, and sepsis.

Perioperative Inflammation and Its Modulation by Anesthetics

Surgery and other invasive procedures, which are routinely performed during general anesthesia, may induce an inflammatory response in the patient. This inflammatory response is an inherent answer of the body to the intervention and can be both beneficial and potentially harmful. The immune system represents a unique evolutionary achievement equipping higher organisms with an effective defense mechanism against exogenous pathogens. However, not only bacteria might evoke an immune response but also other noninfectious stimuli like the surgical trauma or mechanical ventilation may induce an inflammatory response of varying degree. In these cases, the immune system activation is not always beneficial for the patients and might carry the risk of concomitant, harmful effects on host cells, tissues, or even whole organ systems. Research over the past decades has contributed substantial information in which ways surgical patients may be affected by inflammatory reactions. Modulations of the patient's immune system may be evoked by the use of anesthetic agents, the nature of surgical trauma and the use of any supportive therapy during the perioperative period. The effects on the patient may be manifold, including various proinflammatory effects. This review focuses on the causes and effects of inflammation in the perioperative period. In addition, we also highlight possible approaches by which inflammation in the perioperative may be modulated in the future.

Risk factors for death in septic shock: A retrospective cohort study comparing trauma and non-trauma patients

The aim of this study was to compare septic shock directly associated-mortality between severe trauma patients and nontrauma patients to assess the role of comorbidities and age. We conducted a retrospective study in an intensive care unit (ICU) (15 beds) of a university hospital (928 beds). From January 2009 to May 2015, we reviewed 2 anonymized databases including severe trauma patients and nontrauma patients. We selected the patients with a septic shock episode. Among 385 patients (318 nontrauma patients and 67 severe trauma patients), the ICU death rate was 43%. Septic shock was directly responsible for death among 35% of our cohort, representing 123 (39%) nontrauma patients and 10 (15%) trauma patients (P < 0.0). A sequential organ failure assessment score above 12 (odds ratio [OR]: 6.8; 95% confident interval (CI) [1.3-37], P = 0.025) was independently associated with septic shock associated-mortality, whereas severe trauma was a protective factor (OR: 0.26; 95% CI [0.08-0.78], P = 0.01). From these independent risk factors, we determined the probability of septic shock associated-mortality. The receiver-operating characteristics curve has an area under the curve at 0.76 with sensitivity of 55% and specificity of 86%. Trauma appears as a protective factor, whereas the severity of organ failure has a major role in the mortality of septic shock. However, because of the study's design, unmeasured confounding factors should be taken into account in our findings.

Bloodstream Infections

Bacteremia and sepsis are conditions associated with high mortality and are of great impact to health care operations. Among the top causes of mortality in the United States, these conditions cause over 600 fatalities each day. Empiric, broad-spectrum treatment is a common but often a costly approach that may fail to effectively target the correct microbe, may inadvertently harm patients via antimicrobial toxicity or downstream antimicrobial resistance. To meet the diagnostic challenges of bacteremia and sepsis, laboratories must understand the complexity of diagnosing and treating septic patients, in order to focus on creating algorithms that can help direct a more targeted approach to antimicrobial therapy and synergize with existing clinical practices defined in new Surviving Sepsis Guidelines. Significant advances have been made in improving blood culture media; as yet no molecular or antigen-based method has proven superior for the detection of bacteremia in terms of limit of detection. Several methods for rapid molecular identification of pathogens from blood cultures bottles are available and many more are on the diagnostic horizon. Ultimately, early intervention by molecular detection of bacteria and fungi directly from whole blood could provide the most patient benefit and contribute to tailored antibiotic coverage of the patient early on in the course of the disease. Although blood cultures remain as the best means of diagnosing bacteremia and candidemia, complementary testing with antigen tests, microbiologic investigations from other body sites, and histopathology can often aid in the diagnosis of disseminated disease, and application of emerging nucleic acid test methods and other new technology may greatly impact our ability to bacteremic and septic patients, particularly those who are immunocompromised.

Features of Postoperative Immune Suppression Are Reversible With Interferon Gamma and Independent of Interleukin-6 Pathways

OBJECTIVE

The aim of this study was to evaluate the role of interleukin (IL)-6 pathways in postoperative immune suppression and to assess the reversibility of this phenomenon.

BACKGROUND

The postoperative period is characterized by increased IL-6 production and features of immune suppression. In vitro, IL-6 mediates anti-inflammatory effects through inhibition of interferon gamma (IFN-γ) pathways. The significance of the immunomodulatory effects of IL-6 in the clinical setting of postoperative immune suppression remains unclear.

METHODS

Patients over 45 years old undergoing elective surgery, involving the gastrointestinal tract, were recruited. IL-6 levels were assayed using an enzyme linked immunosorbent assay preoperatively, and at 24 and 48 hours. Peripheral blood mononuclear cells from healthy volunteers were cultured in perioperative serum and CD14Human Leukocyte Antigen-DR (HLA-DR) [monocyte HLA-DR (mHLA-DR)] geometric mean florescent intensity was measured in the presence and absence of IL-6 neutralizing antibody and recombinant IFN-γ.

RESULTS

Of the 108 patients, 41 developed a postoperative infection. The IL-6 levels increased 19-fold from the preoperative sample to 24 hours postoperatively (P < 0.0001). Higher IL-6 levels at 24 (P = 0.0002) and 48 hours (P = 0.003) were associated with subsequent postoperative infectious complications. mHLA-DR mean florescent intensity fell when healthy peripheral blood mononuclear cells were cultured with postoperative serum compared with preoperative serum (P = 0.008). This decrease was prevented by the presence of IFN-γ in the culture media, but not by the presence of IL-6-neutralizing antibody.

CONCLUSIONS

IL-6 levels increase after a major surgery and are associated with an increased susceptibility to postoperative infections. Serum obtained from postoperative patients induces an immunosuppressive response, reflected in reduced mHLA-DR levels, mediated through IL-6 independent pathways and is reversible with IFN-γ. These data may have therapeutic implications for the prevention of infection in patients undergoing major surgery.

Endothelial protein C receptor polymorphisms and risk of sepsis in a Chinese population

Objective

To examine the potential relationship of EPCR polymorphisms and the risk of sepsis in a Chinese population.

Methods

Snapshot SNP genotyping assays and DNA sequencing methods were used to detect polymorphisms of the EPCR gene, rs2069948C/T (2532C/T) and rs867186A/G (6936A/G), in 64 patients with sepsis and in 113 controls. Soluble EPCR (sEPCR) was measured by ELISA.

Results

There were significant differences in the allele and genotype frequencies of EPCR gene rs2069948C/T and allele frequencies of rs867186A/G between male and female patients and controls. Females carrying rs2069948 C/T genotype or T allele and males carrying rs867186 A allele were associated with a significantly increased risk of sepsis. Plasma sEPCR levels of sepsis patients were higher than controls and showed no correlation with EPCR gene polymorphisms.

Conclusions

EPCR polymorphisms may be associated with increased risk of sepsis, but this has no effect on the release of sEPCR in patients with sepsis.

Incidence and predictive risk factors of postoperative sepsis in orthopedic trauma patients

Background

Postoperative sepsis is associated with high mortality and the national costs of septicemia exceed those of any other diagnosis. While numerous studies in the basic orthopedic science literature suggest that traumatic injuries facilitate the development of sepsis, it is currently unclear whether orthopedic trauma patients are at increased risk. The purpose of this study was thus to assess the incidence of sepsis and determine the risk factors that significantly predicted septicemia following orthopedic trauma surgery.

Materials and methods

56,336 orthopedic trauma patients treated between 2006 and 2013 were identified in the ACS-NSQIP database. Documentation of postoperative sepsis/septic shock, demographics, surgical variables, and preoperative comorbidities was collected. Chi-squared analyses were used to assess differences in the rates of sepsis between trauma and nontrauma groups. Binary multivariable regressions identified risk factors that significantly predicted the development of postoperative septicemia in orthopedic trauma patients.

Results

There was a significant difference in the overall rates of both sepsis and septic shock between orthopedic trauma (1.6%) and nontrauma (0.5%) patients (p < 0.001). For orthopedic trauma patients, ventilator use (OR = 15.1, p = 0.002), history of pain at rest (OR = 2.8, p = 0.036), and prior sepsis (OR = 2.6, p < 0.001) were significantly associated with septicemia. Statistically predictive, modifiable comorbidities included hypertension (OR = 2.1, p = 0.003) and the use of corticosteroids (OR = 2.1, p = 0.016).

Conclusions

There is a significantly greater incidence of postoperative sepsis in the trauma cohort. Clinicians should be aware of these predictive characteristics, may seek to counsel at-risk patients, and should consider addressing modifiable risk factors such as hypertension and corticosteroid use preoperatively.

Level of evidence Level III.

Post-Operative Infection Is an Independent Risk Factor for Worse Long-Term Survival after Colorectal Cancer Surgery

BACKGROUND

Colorectal cancer surgery is associated with a high incidence of post-operative infections, the outcome of which may be improved if diagnosed and treated early enough. We compared white blood cell (WBC) count, C-reactive protein (CRP), and procalcitonin (PCT) as predictors of post-operative infections and analyzed their impact on long-term survival.

METHODS

This retrospective study included 186 patients undergoing colorectal surgery. Post-operative values of WBC, CRP, and PCT were analyzed by the receiver operating characteristic (ROC) analysis. We followed infections 30 d after the surgery. A five-year survival was analyzed by Kaplan-Meier method and prognostic factors by Cox regression model.

RESULTS

Fifty-five patients (29.5%) developed post-operative infection, the most frequent of which was surgical site infection (SSI). C-reactive protein on post-operative day three and PCT on post-operative day two demonstrated the highest diagnostic accuracy for infection (area under the curve [AUC] 0.739 and 0.735). C-reactive protein on post-operative day three was an independent predictor of infection. Five-year survival was higher in the non-infected group (70.8%), compared with the infected group (52.1%). The worst survival (40.9%) was identified in patients with organ/space SSI. Post-operative infection and tumor stage III-IV were independent predictors of a worse five-year survival.

CONCLUSIONS

C-reactive protein on post-operative day three and PCT on post-operative day two may be early predictors of infection after colorectal cancer surgery. Post-operative infections in particular organ/space SSI have a negative impact on long-term survival.

Sepsis following cancer surgery: the need for early recognition and standardised clinical care

Despite the implementation of multimodal bundles of care in hospitalised patients, post-operative sepsis in patients with cancer still accounts for a significant burden of illness and substantial healthcare costs. Patients undergoing surgery for cancer are at particular risk of sepsis due to underlying malignancy, being immunocompromised associated with cancer management and the complexity of surgical procedures performed. In this review, we evaluate the burden of illness and risks for sepsis following surgery for cancer. Current evidence supporting standardised strategies for sepsis management (including early recognition and resuscitation) is examined together with challenges in implementing quality improvement programs.

The perioperative immune response

PURPOSE OF REVIEW

A host of immune modulators are now available in clinical practice. The perioperative period is characterized by profound alterations in host immunity, which can result in poor outcomes, which include infection, cancer recurrence and organ failure. Manipulation of the perioperative immune response has the potential to improve outcomes. A complete understanding of the mechanisms and clinical consequences of altered immune function in this setting is therefore imperative.

RECENT FINDINGS

Recent in-vivo data have emerged which further our understanding of the interaction between tissue damage, immune modulation and clinical outcomes by utilizing novel laboratory techniques capable of monitoring single-cell immune signatures. Traditional gene expression assays have continued to demonstrate their utility and have been instrumental in defining the host response to perioperative allogeneic blood transfusion. These mechanistic studies are complemented by large clinical studies describing associations between anaesthetic modalities and immune-related outcomes.

SUMMARY

Laboratory techniques are now available that can monitor the perioperative immune response and could be further developed to introduce personalized care pathways. Consideration must also be given to anaesthesia techniques and perioperative treatments that, although not immediately harmful, may be associated with poor outcomes temporally distant from the treatment, secondary to induced immunosuppression.

Pathogenesis of infection in surgical patients

Purpose of review

Despite the application of prophylactic antimicrobial therapy and advanced technologies, infection remains one of the most common causes of morbidity and mortality in surgical patients. Understanding the pathogenesis of surgical infection would offer new insights into the development of biomarkers to predict and stratify infection in patients, and to explore specific strategies to minimize this serious postoperative complication.

Recent findings

The acute nonspecific inflammatory response triggered by endogenous danger signals evoked by surgical insult is beneficial, while paradoxically associated with reduced resistance to infection. There is growing evidence indicating that primed inflammation by surgical insult exaggerates the dysregulation of the immune-inflammatory response to the invasion of pathogens postoperatively. Innate immune receptors, such as Toll-like receptors (TLRs), contribute to detecting both pathogen-associated molecular patterns and endogenous damage-associated molecular patterns, and to further amplifying inflammatory responses to infection. Current evidence shows the fascinating role of non-TLRs in the process of infection. Non-TLRs, such as membrane-associated triggering receptor expressed on myeloid cells family, cytosolic nucleotide-binding oligomerization domain-like receptors and nuclear receptor nuclear family 4 subgroup A receptors, are also crucial in triggering the immune responses and mounting an effective defense against surgical insults and the second hit of infection.

Summary

Understanding the pivotal role of non-TLRs in sensing exogenous and endogenous molecules, and the influence of primed systemic inflammation and depressed immune status on the defense against pathogen after surgical insult, would be helpful to fully explore the relevant sophisticated phenomena of surgical infection, and to elucidate the occurrence of heterogeneous constellations of clinical signs and symptoms among this special population.

Postoperative sepsis in cancer patients undergoing major elective digestive surgery is associated with increased long-term mortality

BACKGROUND

Major postoperative events (acute respiratory failure, sepsis, and surgical complications) are frequent early after elective gastroesophageal and pancreatic surgery. It is unclear whether these complications impact equally on long-term outcome.

METHODS

Prospective observational study including the patients admitted to the surgical intensive care unit between January 2009 and October 2011 after elective gastroesophageal and pancreatic surgery. Risk factors for 30-day major postoperative events and long-term outcome were evaluated.

RESULTS

During the study period, 259 patients were consecutively included. Among them, 166 (64%), 54 (21%), and 39 (15%) patients underwent pancreatic surgery, gastric surgery, and esophageal surgery, respectively. Using the Clavien-Dindo classification, 117 patients (45%) developed at least 1 postoperative complication, including 60 (23%) patients with acute respiratory failure, 77 (30%) with sepsis, and 89 (34%) with surgical complications. The median follow-up from the time of intensive care unit admission was 34 months (95% confidence interval, 30-37 months). The 1-year survival was 95% (95% confidence interval, 92-98). Among the perioperative variables, postoperative sepsis and an American Society of Anesthesiologists score higher than 2 were independently associated with long-term mortality. In septic patients, death (n = 16) was significantly associated with cancer recurrence (n = 10; P < .0001). Independent factors associated with postoperative sepsis were a Sequential Organ Failure Assessment score on day 1, a systemic inflammatory response syndrome on day 3, positive intraoperative microbiological samples, Simplified Acute Physiology Score II and an American Society of Anesthesiologists score higher than 2 (P < .005).

CONCLUSIONS

Postoperative sepsis was the only major postoperative event associated with long-term mortality. Postoperative sepsis may reflect a deep impairment of immune response, which is potentially associated with cancer recurrence and mortality.

Predictors of septic shock following anastomotic leak after major gastrointestinal surgery: An audit from a tertiary care institute

Background:

Anastomotic leak is a serious complication after major gastrointestinal surgery and majority of deaths occur due to septic shock. Therefore, the early identification of risk factors of septic shock may help reduce the adverse outcomes.

Objective:

The aim of this audit was to determine the predictors of septic shock in patients with anastomotic leak after major gastrointestinal surgery.

Design:

Retrospective, audit.

Materials and Methods:

The patients admitted in the gastrosurgical intensive care unit ICU) of our institute between September 2009 and April 2012 with anastomotic leakage after surgery were identified. The ICU charts were retrieved from the database to identify the patients progressing to septic shock. A comparison of risk factors was made between the patients who developed septic shock (septic shock group) against the patients who did not (non-septic shock group).

Results:

The study sample comprised of 103 patients with anastomotic leak, of which 72 patients developed septic shock. The septic shock group had a higher APACHE II score, lower MAP, and higher HR at the time of ICU admission. They received greater transfusion of packed red blood cells during their ICU stay. Septic shock was more common after pancreaticojejunostomy and hepaticojejunostomy leaks.

Conclusion:

Presence of malignancy, chronic obstructive pulmonary disease (COPD), packed red blood cell transfusion, bacteremia, and hepaticojejunostomy or pancreaticojejunostomy leaks were independent predictors of mortality and length of ICU stay. To the best of our knowledge there are no available studies in the literature on the predictors of risk factors of septic shock in patients with anastomotic leakage.

Risk of morbidity, mortality, and recurrence after parastomal hernia repair: a nationwide study

BACKGROUND

Surgical outcome results after repair for parastomal hernia are sparsely reported and based on small-scale studies.

OBJECTIVE

This study aims to analyze surgical risk factors for 30-day reoperation and mortality, and, secondarily, to report the risk of reoperation for recurrence.

DESIGN

This is a retrospective analysis of nationwide perioperative surgical variables. The primary outcome was reoperation for surgical complications and/or mortality within 30 days after parastomal hernia repair. Follow-up was obtained from the Danish National Patient Register. Detailed patient-related data were based on hospital files. Multivariate analysis was based on a compound parameter: 30-day reoperation or death.

SETTING AND PATIENTS

All patients with a parastomal hernia repair registered in the Danish Hernia Database from January 1, 2007 to December 31, 2010 were included.

MAIN OUTCOME MEASURES

Univariate and logistic regression was used to identify risk factors for 30-day reoperation or death.

RESULTS

The study included 174 patients with a parastomal hernia repair (142 elective and 32 emergency repairs; 56 open and 118 laparoscopic repairs). Median follow-up was 20 months (range, 0-47). A total of 13.2% were reoperated because of postoperative complications, and 6.3% of patients died within the first 30 postoperative days. Emergency repair was the strongest risk factor for reoperation or death in multivariate analyses (OR, 7.6; 95% CI, 2.7-21.5). No difference was found in preoperative risk of poor outcome between elective and emergency repairs (Charlson score 4 (range, 0-12) vs 5 (0-11), p = 0.07). After 3 years, the cumulated reoperation rate for recurrence was 10.8% (open 17.2% and laparoscopic 3.8%).

LIMITATIONS

Patients' comorbidity was based on retrospective data, and the study had a relatively short follow-up.

CONCLUSION

In the present nationwide study, repair for a parastomal hernia was associated with high rates of morbidity, mortality, and repair for recurrence. Emergency repair was the only important risk factor to predict poor 30-day postoperative outcome.

Current trends in inflammatory and immunomodulatory mediators in sepsis

Sepsis refers to severe systemic inflammation in response to invading pathogens. An overwhelming immune response, as mediated by the release of various inflammatory mediators, can lead to shock, multiple organ damage, and even death. Cytokines, proteases, lipid mediators, gaseous substances, vasoactive peptides, and cell stress markers play key roles in sepsis pathophysiology. Various adhesion molecules and chemokines sequester and activate neutrophils into the target organs, further augmenting inflammation and tissue damage. Although the anti-inflammatory substances counterbalance proinflammatory mediators, prolonged immune modulation may cause host susceptibility to concurrent infections, thus reflecting enormous challenge toward developing effective clinical therapy against sepsis. To understand the complex interplay between pro- and anti-inflammatory phenomenon in sepsis, there is still an unmet need to study newly characterized mediators. In addition, revealing the current trends of novel mediators will upgrade our understanding on their signal transduction, cross-talk, and synergistic and immunomodulating roles during sepsis. This review highlights the latest discoveries of the mediators in sepsis linking to innate and adaptive immune systems, which may lead to resolution of many unexplored queries.

Hyperglycaemia, inflammation, RAS activation: three culprits to blame for acute kidney injury emerging in healthy rats during general anaesthesia

AIM

Major surgery under general anaesthesia might evoke acute kidney injury (AKI), sometimes culminating in end stage renal disease. We investigated the roles of hyperglycaemia, inflammation and renin-angiotensin system (RAS) activation in induction of AKI following anaesthesia by different anaesthetic drugs and/or regimens.

METHODS

Ninety-four Sprague-Dawley rats underwent 1 h-anaesthesia by various protocols, including repeated blood glucose and insulin measurements. Blood samples and kidneys were allocated at sacrifice, for evaluation of renal function, inflammatory status and Angiotensin-II availability.

RESULTS

Hyperglycaemia emerged in unconscious rats irrespective of anaesthetic drug choice or anaesthesia regimen. Insulin increase correlated with hyperglycaemia levels. Levels of Cystatin-C, as well as serum and urine neutrophil gelatinase-associated lipocain (NGAL), were significantly augmented. Serum transforming growth factor beta (TGF-β) and interleukins (IL)-1β, -4, -6, and -10 were significantly increased. Intra-renal Angiotensin-II, TGF-β, IL-6 and-10 were significantly increased. IL-1 was decreased. IL-4 remained unaltered.

CONCLUSIONS

Acute hyperglycaemia, systemic and intra-renal inflammation and RAS activation were independently triggered by induction of anaesthesia. Each confounder aggravated the impacts of the others, bringing about concomitant deterioration of renal function. Increased insulin secretion attenuated but did not abolish hyperglycaemia. Systemic inflammation was counterforced by anti-inflammatory cytokines, whereas intra-renal inflammation persisted, so that AKI progressed unopposed.

Logistic Organ Dysfunction Score (LODS): a reliable postoperative risk management score also in cardiac surgical patients?

BACKGROUND

The original Logistic Organ Dysfunction Sore (LODS) excluded cardiac surgery patients from its target population, and the suitability of this score in cardiac surgery patients has never been tested. We evaluated the accuracy of the LODS and the usefulness of its daily measurement in cardiac surgery patients. The LODS is not a true logistic scoring system, since it does not use β-coefficients.

METHODS

This prospective study included all consecutive adult patients who were admitted to the intensive care unit (ICU) after cardiac surgery between January 2007 and December 2008. The LODS was calculated daily from the first until the seventh postoperative day. Performance was assessed with Hosmer-Lemeshow (HL) goodness-of-fit test (calibration) and receiver operating characteristic (ROC) curves (discrimination) from ICU admission day until day 7. The outcome measure was ICU mortality.

RESULTS

A total of 2801 patients (29.6% female) with a mean age of 66.4 ± 10.7 years were included. The ICU mortality rate was 5.2% (n = 147). The mean stay on the ICU was 4.3 ± 6.8 days. Calibration of the LODS was good with no significant difference between expected and observed mortality rates on any day (p ≥ 0.05). The initial LODS had an area under the ROC curve (AUC) of 0.81. The AUC was best on ICU day 3 with a value of 0.93, and declined to 0.85 on ICU day 7.

CONCLUSIONS

Although the LODS has not previously been validated for cardiac surgery patients it showed reasonable accuracy in prediction of ICU mortality in patients after cardiac surgery.

C-reactive protein in the diagnosis of postoperative infection in pediatric patients: a prospective observational study of 103 patients

BACKGROUND

Surgical stress elicits a systemic inflammatory response syndrome that contributes to the development of septic complications. C-reactive protein (CRP) is an acute phase protein released in inflammatory states. To analyze the usefulness of CRP as a marker of infection in surgical pediatric patients, we analyzed its kinetics in these patients in comparison with usual markers, such temperature, leukocytes, or fibrinogen.

METHODS

One hundred three pediatric patients undergoing major surgery were enrolled consecutively in this observational study. C-reactive protein, leukocytes, neutrophils, platelets, fibrinogen, glycemia, and temperature were determined daily after surgery. Patients were classified as infected or not infected. Sensitivity, specificity, positive predictive value, negative predictive value, efficiency, precocity, positive likelihood ratio, and number of subjects to be treated were calculated.

RESULTS

Peak in CRP was detected at 48 ± 24 hours. C-reactive protein was higher in the infected group from the first day, with significant differences between groups from the second day. Best cutoff for detecting infection was increases in CRP of 11 mg/dL in 48 hours, with a sensitivity of 87%, specificity of 89%, precocity of 1.7 days (0.82-2.54), number of subjects to be treated of 1.7 (1.4-2.6), and positive likelihood ratio of 7.9. Application of other markers alone or in combination did not surpass the sensitivity, specificity, or precocity for increases in CRP of 11 mg/dL in 48 hours.

CONCLUSIONS

Increases of CRP constitute an easy and cheap prognostic alert system and may be used to establish strategies aimed to detect infection in surgical pediatric patients.

An evaluation of the Charlson co-morbidity score for predicting sepsis after elective major surgery

BACKGROUND AND AIMS

Severe sepsis is a significant cause of morbidity and mortality following major surgery. The Charlson co-morbidity score (CCS) has been shown to be associated with severe sepsis following major surgery for cancer. This prospective observational study investigated the effect of patient factors (CCS, gender, age and malignancy) and intraoperative factors (duration of surgery and allogeneic blood transfusion) on the incidence of sepsis after elective major surgery, and the impact of patient co-morbidities on length of stay in critical care.

MATERIALS AND METHODS

We prospectively identified a cohort of 101 patients undergoing elective major surgery in a university teaching hospital. The CCS was calculated before surgery, and the incidence of sepsis was documented following surgery. We investigated whether age, malignancy, intraoperative allogeneic blood transfusion, length of surgery or gender were associated with sepsis following surgery.

RESULTS

Twenty-seven (27%) patients developed sepsis. Using multivariate logistic regression, the duration of surgery was associated with the development of sepsis after surgery (P = 0.054, odds ratio 1.2). The CCS was not associated with sepsis in this population of cancer and non-cancer patients undergoing elective major surgery, but was associated with longer length of stay in the intensive care unit (P = 0.016).

CONCLUSIONS

Duration of surgery, but not patient co-morbidity as assessed by the CCS, may predict the postoperative incidence of sepsis. CCS could be used as a guide to predict consumption of critical care resources by elective surgical patients. A higher CCS was associated with a longer ICU stay. Resources, such as postoperative goal directed therapy, may be useful in reducing length of stay, hospital costs and risks of infective complications in this subgroup of patients with higher CCS.

The Charlson Comorbidity Index Score as a Predictor of 30-Day Mortality After Hip Fracture Surgery

This study is a retrospective chart review to determine the association of Charlson Comorbidity Index (CCI), age, body mass index (BMI), and admission glucose with the incidence of postoperative 30-day mortality in older patients undergoing hip fracture surgery from January 1, 2000, to June 30, 2002. A total of 40 (8%) of 485 eligible patients died within 30 days after hip fracture surgery. The factors associated with 30-day mortality were age > 90 years (odds ratio [OR] = 2.74; confidence interval [CI] = 1.27-5.95; P = .012), BMI < 18.5 (OR = 3.98; CI 1.48-10.65; P = .006), and CCI ≥ 6 (OR = 2.6; CI = 1.20-5.65; P = .015). There was no relationship between admission glucose concentration and 30-day mortality. Advanced age, low BMI, and high CCI can be identified prospectively and are independently associated with postoperative 30-day mortality in older, chronically ill patients.

Postoperative sepsis in the United States

OBJECTIVES

To evaluate the incidence of postoperative sepsis after elective procedures, to define surgical procedures with the greatest risk for developing sepsis, and to evaluate patient and hospital confounders.

BACKGROUND DATA

The development of sepsis after elective surgical procedures imposes a significant clinical and resource utilization burden in the United States. We evaluated the development of sepsis after elective procedures in a nationally representative patient cohort and assessed the effect of sociodemographic and hospital characteristics on the development of postoperative sepsis.

METHODS

The Nationwide inpatient sample was queried between 2002 and 2006 and patients developing sepsis after elective procedures were identified using the patient safety indicator "Postoperative Sepsis" (PSI-13). Case-mix adjusted rates were calculated by using a multivariate logistic regression model for sepsis risk and an indirect standardization method.

RESULTS

A total of 6,512,921 weighted elective surgical cases met the inclusion criteria and 78,669 cases (1.21%) developed postoperative sepsis. Case-mix adjustment for age, race, gender, hospital bed size, hospital location, hospital teaching status, and patient income demonstrated esophageal, pancreatic, and gastric procedures represented the greatest risk for the development of postoperative sepsis. Thoracic, adrenal, and hepatic operations accounted for the greatest mortality rates if sepsis developed. Increasing age, Blacks, Hispanics, and men were more likely to develop sepsis. Decreased median household income, larger hospital bed size, urban hospital location, and nonteaching status were associated with greater rates of postoperative sepsis.

CONCLUSIONS

The development of postoperative sepsis is multifactorial and procedures, most likely to develop sepsis, did not demonstrate the greatest mortality after sepsis developed. Factors associated with the development of sepsis included race, age, hospital size, hospital location, and patient income. Further evaluation of high-risk procedures, populations, and environments may assist in reducing this costly complication.

Sex-related differences in gene expression following Coxiella burnetii infection in mice: potential role of circadian rhythm

Background

Q fever, a zoonosis due to Coxiella burnetii infection, exhibits sexual dimorphism; men are affected more frequently and severely than women for a given exposure. Here we explore whether the severity of C. burnetii infection in mice is related to differences in male and female gene expression profiles.

Methodology/Principal Findings

Mice were infected with C. burnetii for 24 hours, and gene expression was measured in liver cells using microarrays. Multiclass analysis identified 2,777 probes for which expression was specifically modulated by C. burnetti infection. Only 14% of the modulated genes were sex-independent, and the remaining 86% were differentially expressed in males and females. Castration of males and females showed that sex hormones were responsible for more than 60% of the observed gene modulation, and this reduction was most pronounced in males. Using functional annotation of modulated genes, we identified four clusters enriched in males that were related to cell-cell adhesion, signal transduction, defensins and cytokine/Jak-Stat pathways. Up-regulation of the IL-10 and Stat-3 genes may account for the high susceptibility of men with Q fever to C. burnetii infection and autoantibody production. Two clusters were identified in females, including the circadian rhythm pathway, which consists of positive (Clock, Arntl) and negative (Per) limbs of a feedback loop. We found that Clock and Arntl were down-modulated whereas Per was up-regulated; these changes may be associated with efficient bacterial elimination in females but not in males, in which an exacerbated host response would be prominent.

Conclusion

This large-scale study revealed for the first time that circadian rhythm plays a major role in the anti-infectious response of mice, and it provides a new basis for elucidating the role of sexual dimorphism in human infections.

Upregulation of TLR2/4 expression in mononuclear cells in postoperative systemic inflammatory response syndrome after liver transplantation

BACKGROUND

To explore the relationship between Toll-like rpheral blood mononuclear cells (PBMC) and systemic inflammatory response syndrome (SIRS) in postoperative patients of liver transplantation (LT).

METHODS

Blood samples of 27 patients receiving LT were collected at T1 (after induction of anaesthesia), T2 (25 minutes after the beginning of anhepatic phase), T3 (3 hours after graft reperfusion), and T4 (24 hours after graft reperfusion). The expression of TLR2/4 on PBMC and serum concentration of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-8 were measured. The patients were divided into SIRS group (n = 12) and non-SIRS group (n = 15) for analysis.

RESULTS

Blood loss and transfusion were higher in the SIRS group than in the non-SIRS group. Both the preanhepatic and anhepatic phase were significantly longer in the SIRS group. The TLR2/4 expression on PBMC as well as serum TNF-alpha, IL-1beta, and IL-8 were significantly higher at T3 and T4 than that at T1 and T2 in the SIRS patients. The expression of TLR4 on PBMC is positively correlated to serum TNF-alpha, IL-8. Expression of TLR2/4 on PBMC and serum concentrations of TNF-alpha, IL-1beta, did not differ among the 4-time points in non-SIRS patients.

CONCLUSIONS

Upregulation of TLR2/4 expression on PBMC may contribute to the development of postoperative SIRS during perioperative period of LT.

Differences in immune response may explain lower survival among older men with pneumonia

OBJECTIVE

Lower life expectancy in men is generally attributed to higher likelihood of risky behavior and because men develop chronic conditions earlier. If sex-related differences in survival are independent of preinfection chronic health and health behavior, it would suggest that survival differences may occur because of sex differences in quality of care and biological response to infection, and these differences may contribute to sex differences in life expectancy. We assessed if sex-related survival difference following community-acquired pneumonia (CAP) is due to differences in clinical characteristics, quality of care, or immune response.

DESIGN, SETTING, AND SUBJECTS

Prospective observational cohort of 2183 subjects with CAP.

MEASUREMENTS AND MAIN RESULTS

Mean age was 64.9 years. Men were more likely to smoke and had more comorbidity compared with women. At emergency department presentation, men had different biomarker patterns, as evidenced by higher inflammation (tumor necrosis factor, interleukin [IL]-6, and IL-10) and fibrinolysis (d-dimer), and lower coagulation biomarkers (antithrombin-III and factor IX) (p < 0.05). Small differences in favor of men were seen in care quality, including antibiotic timing and compliance with American Thoracic Society guidelines. Men had lower survival at 30, 90, and 365 days. The higher 1-year mortality was not attenuated when adjusted for differences in demographics, smoking, resuscitation, insurance, and vaccination status, comorbidity, hospital characteristics, and illness severity (unadjusted hazard ratio [HR] = 1.35, p = 0.003; and adjusted HR = 1.29, p = 0.004). HR was no longer statistically significant when additionally adjusted for differences in emergency department concentrations of tumor necrosis factor, IL-6, IL-10, d-dimer, antithrombin-III, and factor IX (adjusted HR = 1.27, p = 0.17). Patterns of biomarkers observed in men were associated with worse survival for 1 year.

CONCLUSIONS

Lower survival among men following CAP was not explained by differences in chronic diseases, health behaviors, and quality of care. Patterns of inflammatory, coagulation, and fibrinolysis biomarkers among men may explain reduced short-term and long-term survival.

Trends in postoperative sepsis: are we improving outcomes?

BACKGROUND AND PURPOSE

Each year, as many as two million operations are complicated by surgical site infections in the United States, and surgical patients account for 30% of patients with sepsis. The purpose of this study was to determine recent trends in sepsis incidence, severity, and mortality rate after surgical procedures and to evaluate changes in the pattern of septicemia pathogens over time.

METHODS

Analysis of the 1990-2006 hospital discharge data from the Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases (SID) for New Jersey. Patients >or= 18 years who developed sepsis after surgery were identified using International Classification of Diseases, Ninth Revision, Clinical Modification codes as defined by the Patient Safety Indicator "Postoperative Sepsis" developed by the Agency for Healthcare Research and Quality (AHRQ). Severe sepsis was defined as sepsis complicated by organ dysfunction.

RESULTS

A total of 1,276,451 surgery discharges (537,843 elective [42.1%] and 738,608 non-elective [57.9%] procedures) were identified. After elective surgery, 5,865 patients (1.09%) developed postoperative sepsis, of whom 2,778 (0.52%) had severe sepsis. The incidence of postoperative sepsis after elective surgery increased from 0.67% to 1.74% (p < 0.0001) and severe sepsis after elective surgery from 0.22% to 1.12% (p < 0.0001). The sepsis mortality rate for elective procedures showed no significant change over time. The proportion of severe sepsis after elective cases increased from 32.9% to 64.6% (p < 0.0002). The rates of postoperative sepsis (4.24%) and severe sepsis (2.28%) were significantly greater for non-elective than for elective procedures (p < 0.0002). Non-elective surgical procedures had a significant increase in the rates of postoperative sepsis (3.74% to 4.51%) and severe sepsis (1.79% to 3.15%) over time (p < 0.0001) with the proportion of severe sepsis increasing from 47.7% to 69.9% (p < 0.0002). The in-hospital mortality rate after non-elective surgery decreased from 37.9% to 29.8% (p < 0.0001).

CONCLUSIONS

Sepsis and death were more likely after non-elective than elective surgery. Sepsis and severe sepsis has increased significantly after elective and non-elective procedures over the last 17 years. The hospital mortality rate was reduced significantly after non-elective surgery, but no improvements were found for elective surgery patients who developed sepsis. Disparities in age, sex, and ethnicity and the development of postoperative surgical sepsis were found. Population-based studies may assist in defining temporal trends, disparities, and outcomes in sepsis not elucidated in smaller studies.

Tumour necrosis factor-alpha (TNFα) and interleukin-10 are crucial mediators in post-operative systemic inflammatory response and determine the occurrence of complications after major abdominal surgery

BACKGROUND

The course of serum cytokine levels in patients with postoperative systemic inflammatory response syndrome (SIRS) after major abdominal surgery remains currently unclear.

METHODS

Blood was sampled pre- and post-operatively and on days 1 and 2 in 40 patients undergoing major abdominal surgery. Concentrations of tumour necrosis factor-alpha (TNFalpha), interleukin (IL) -6, IL-8, and IL-10 were measured by the LINCOplex assay; those of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) by an enzyme immunoassay.

RESULTS

Compared to their pre-operative values, sTREM-1 was elevated on day 2; TNFalpha on day 1; IL-6 and IL-10 post-operatively and on days 1 and 2; and IL-8 post-operatively and on day 1. The duration of operation correlated with TNFalpha and IL-10 at all sampling times, and with IL-6 post-operatively. There were no differences in cytokine concentrations between patients who exhibited post-operative complications and those who did not. IL-10/TNFalpha below 30 was found in all patients with complications (100%) and in 20 patients without complications (64.5%, p: 0.043).

CONCLUSIONS

SIRS following major surgery is characterised by complex alterations in cytokine concentrations. The balance between TNFalpha and IL-10 seems to determine the occurrence of post-operative complications.

Management of Severe Sepsis in the Surgical Patient

Sepsis and septic shock are not uncommon conditions in the surgical intensive care unit. Sepsis is a generalized activation of the immune system in the presence of clinically suspected or culture-proven infection. Severe sepsis is sepsis with organ system dysfunction. Septic shock is sepsis with hypotension (systolic blood pressure <90 mm Hg) without other causes. Although the incidence of sepsis is increasing, the case fatality rate is falling. This improvement in outcome is in part due to bold initiatives like the Surviving Sepsis Campaign from the Institute for Health Care Improvement. In this article the authors present the epidemiology of severe sepsis and evidence-based campaigns for its treatment, with a focus on the surgical patient.