Protein C as an early marker of severe septic complications in diffuse secondary peritonitis

The prognostic utility of protein C as a biomarker for adult sepsis: a systematic review and meta-analysis

Background

Sepsis, the dysregulated host response to infection, triggers abnormal pro-coagulant and pro-inflammatory host responses. Limitations in early disease intervention highlight the need for effective diagnostic and prognostic biomarkers. Protein C’s role as an anticoagulant and anti-inflammatory molecule makes it an appealing target for sepsis biomarker studies. This meta-analysis aims to assess the diagnostic and prognostic value of protein C (PC) as a biomarker for adult sepsis.

Methods

We searched MEDLINE, PubMed, EMBASE, CINAHL and Cochrane Library from database inception to September 12, 2021. We included prospective observational studies of (1) adult patients (> 17) with sepsis or suspicion of sepsis that; (2) measured PC levels with 24 h of study admission with; and (3) the goal of examining PC as a diagnostic or prognostic biomarker. Two authors screened articles and conducted risk of bias (RoB) assessment, using the Quality in Prognosis Studies (QUIPS) and the Quality Assessment in Diagnostic Studies-2 (QUADAS-2) tools. If sufficient data were available, meta-analysis was conducted to estimate the standardized mean difference (SMD) between patient populations.

Results

Twelve studies were included, and 8 were synthesized for meta-analysis. Pooled analysis demonstrated moderate certainty of evidence that PC levels were less reduced in sepsis survivors compared to non-survivors (6 studies, 741 patients, SMD = 0.52, 95% CI 0.24–0.81, p = 0.0003, I² = 55%), and low certainty of evidence that PC levels were less reduced in septic patients without disseminated intravascular coagulation (DIC) compared to those with DIC (3 studies, 644 patients, SMD = 0.97, 95% CI 0.62–1.32, p < 0.00001, I² = 67%). PC could not be evaluated as a diagnostic tool due to heterogeneous control populations between studies.

Conclusion and relevance

Our review demonstrates that PC levels were significantly higher in sepsis survivors compared to non-survivors and patients with sepsis but not disseminated intravascular coagulation (DIC). Our evaluation is limited by high RoB in included studies and poor reporting of the sensitivity and specificity of PC as a sepsis biomarker. Future studies are needed to determine the sensitivity and specificity of PC to identify its clinical significance as a biomarker for early sepsis recognition.

Trial Registration PROSPERO registration number: CRD42021229786. The study protocol was published in BMJ Open.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-03889-2.

Fibrinolytic Alterations in Sepsis: Biomarkers and Future Treatment Targets

Sepsis is a life-threatening condition which develops as a dysregulated immune response in the face of infection and which is associated with profound hemostatic disturbances and in the most extreme cases disseminated intravascular coagulation (DIC). In addition, the fibrinolytic system is subject to alterations during infection and sepsis, and impaired fibrinolysis is currently considered a key player in sepsis-related microthrombus formation and DIC. However, we still lack reliable biomarkers to assess fibrinolysis in the clinical setting. Furthermore, drugs targeting the fibrinolytic system have potential value in sepsis patients with severe fibrinolytic disturbances, but these are still being tested in the preclinical stage. The present review provides an overview of key fibrinolytic changes in sepsis, reviews the current literature on potential laboratory markers of altered fibrinolysis in adult sepsis patients, and discusses future perspectives for diagnosis and treatment of fibrinolytic disturbances in sepsis patients.

Management of Severe Sepsis of Abdominal Origin

Severe sepsis is a life-threatening condition that may occur as a sequela of intra-abdominal infections (IAIs) of all types. Diagnosis of IAIs is predicated upon the combination of physical examination and imaging techniques. Diffuse peritonitis usually requires urgent surgical intervention. In the absence of diffuse peritonitis, abdominal computed tomography remains the most useful test for the diagnosis of IAIs, and is essential to both guide therapeutic interventions and evaluate suspected treatment failure in the critically ill patient. Parameters most consistently associated with poor outcomes in patients with IAIs include increased illness severity, failed source control, inadequate empiric antimicrobial therapy, and healthcare-acquired, as opposed to community-acquired infection. Whereas community-acquired IAI is characterized predominantly by enteric gram-negative bacilli and anaerobes that are susceptible to narrow-spectrum agents, healthcare-acquired IAI (e.g., anastomotic dehiscence, postoperative organ-space surgical site infection) frequently involves at least one multi-drug resistant pathogen, necessitating broad-spectrum therapy guided by both culture results and local antibiograms. The cornerstone of effective treatment for abdominal sepsis is early and adequate source control, which is supplemented by antibiotic therapy, restoration of a functional gastrointestinal tract (if possible), and support of organ dysfunction. Furthermore, mitigation of deranged immune and coagulation responses via therapy with recombinant human activated protein C may improve survival significantly in severe cases complicated by septic shock and multiple organ dysfunction syndrome.

Inflammatory mediators in intra-abdominal sepsis or injury - a scoping review

INTRODUCTION

Inflammatory and protein mediators (cytokine, chemokine, acute phase proteins) play an important, but still not completely understood, role in the morbidity and mortality of intra-abdominal sepsis/injury. We therefore systematically reviewed preclinical and clinical studies of mediators in intra-abdominal sepsis/injury in order to evaluate their ability to: (1) function as diagnostic/prognostic biomarkers; (2) serve as therapeutic targets; and (3) illuminate the pathogenesis mechanisms of sepsis or injury-related organ dysfunction.

METHODS

We searched MEDLINE, PubMed, EMBASE and the Cochrane Library. Two investigators independently reviewed all identified abstracts and selected articles for full-text review. We included original studies assessing mediators in intra-abdominal sepsis/injury.

RESULTS

Among 2437 citations, we selected 182 studies in the scoping review, including 79 preclinical and 103 clinical studies. Serum procalcitonin and C-reactive protein appear to be useful to rule out infection or monitor therapy; however, the diagnostic and prognostic value of mediators for complications/outcomes of sepsis or injury remains to be established. Peritoneal mediator levels are substantially higher than systemic levels after intra-abdominal infection/trauma. Common limitations of current studies included small sample sizes and lack of uniformity in study design and outcome measures. To date, targeted therapies against mediators remain experimental.

CONCLUSIONS

Whereas preclinical data suggests mediators play a critical role in intra-abdominal sepsis or injury, there is no consensus on the clinical use of mediators in diagnosing or managing intra-abdominal sepsis or injury. Measurement of peritoneal mediators should be further investigated as a more sensitive determinant of intra-abdominal inflammatory response. High-quality clinical trials are needed to better understand the role of inflammatory mediators.

Anti-C5a complementary peptide ameliorates acute peritoneal injury induced by neutralization of Crry and CD59

In peritoneal dialysis (PD) therapy, physical stresses such as exposure to peritoneal dialysate, catheter trauma, and peritonitis may induce peritoneal injury that can prevent continued long-term PD therapy. Therefore, protection of the peritoneum is an important target to enable long-term PD therapy in patients with end-stage renal disease. We previously showed that neutralization of the membrane complement regulators (CRegs) Crry and CD59 in rat peritoneum provokes development of acute peritoneal injury due to uncontrolled complement activation. C5a is a key effecter molecule of the complement system released during acute inflammation. Control of C5a has been proposed as a strategy to suppress inflammatory reactions and, because peritoneal injury is accompanied by inflammation, we hypothesized that C5a targeted therapy might be an effective way to suppress peritoneal injury. In the present study we used an established acute peritonitis model induced by neutralization of CRegs to investigate the effects on acute peritoneal injury of inhibiting C5a. Intravenous administration of an anti-C5a complementary peptide (AcPepA) up to 4 h after induction of injury significantly and dose-dependently prevented accumulation of inflammatory cells and reduced tissue damage in the model, accompanied by decreased C3b deposition. We show that C5a contributed to the development of peritoneal injury. Our results suggest that C5a is a target for preventing or treating peritoneal injury in patients undergoing prolonged PD therapy or with infectious complications.

The grade-response relation between severity of peritonitis and serum cytokine concentrations explains Mannheim Peritonitis Index threshold

AIM

To explore the gradient between the acute-phase response (APR) and peritonitis of differing severity.

METHODS

In 202 patients with peritonitis, we determined serum concentrations of interleukin (IL)-6, IL-10, IL-13, tumor necrosis factor (TNF)-alpha, and C-reactive protein (CRP). The severity of peritonitis was graded in accordance with the Mannheim Peritonitis Index (MPI). The grade-response relation between the severity of peritonitis and each analyte was explored.

RESULTS

A statistically significant association was found between the medians of severity of peritonitis and IL-6 (p < 0.025), TNF-alpha (p < 0.01), CRP (p < 0.033), IL-10 (p < 0.0001), and IL-13 (p < 0.004). Both TNF-alpha and IL-10 had a direct, and IL-13 an indirect, relation to severity, whereas CRP and IL-6 tended toward linear behavior in equilibrium. A significant association persisted between individual MPI scores and IL-6 (p < 0.002), TNF-alpha (p < 0.002), CRP (p < 0.002), and IL-10 (p < 0.001), but not IL-13 (p = 0.646).

CONCLUSION

Around the mean value of grade II peritonitis, the equilibrium between pro-inflammatory and anti-inflammatory cytokines is lost. This change coincides with the 26-point threshold for the MPI.

C-reactive protein is an early predictor of septic complications after elective colorectal surgery

BACKGROUND

Nowadays, most patients who undergo colorectal surgery are discharged early. An early predictor of septic complications could avoid readmissions and decrease morbidity. CRP could be a good predictor allowing a safe discharge.

METHODS

A prospective, observational study was conducted from November 2007 to October 2008. All patients who underwent elective colorectal surgery were included. Clinical (temperature, pulse, abdominal tenderness, bowel movements) and laboratory data (C-reactive protein, leukocyte count) were recorded and evaluated as early predictors of septic complications (namely, anastomotic leaks). All detected leaks were considered fistulas, independently of their clinical significance. Clinical and inflammatory parameters were analyzed with univariate and multivariate techniques; logistic regression was performed and areas under the receiver operating characteristic curve were compared.

RESULTS

A total of 133 patients were included. The overall incidence of anastomotic leaks was 15.5% and mortality was 4.5%. C-reactive protein at postoperative days 2 and 4 was a good predictor of anastomotic leak (areas under the curve were 0.715 and 0.845, respectively) and other postoperative septic complications (areas under the curve were 0.804 and 0.787), showing the highest accuracy among clinical and laboratory data. A cutoff of 125 mg/l in the level of C-reactive protein at postoperative day 4 yielded a sensitivity of 81.8% and a negative predictive value of 95.8% for the detection of anastomotic leakage.

CONCLUSIONS

C-reactive protein is a simple way to ensure a safe discharge from hospital after elective colorectal surgery. Patients with CRP values >125 mg/l on the fourth postoperative day should not be discharged.

Role of D-dimer testing in severe pelvic inflammatory disease: a new usable marker to assess the need for fertility-impairing surgery?

Pelvic inflammatory disease (PID), like many other inflammatory diseases, can be characterized by an inflammation-induced activation of the coagulation cascade, resulting in the production of D-dimers. In this study it is demonstrated how high levels of D-dimers, assayed at the time of hospitalization, are encountered in patients diagnosed with PID and how the levels of this parameter are significantly higher in patients, which due to the severity of the disease, needed surgical treatment. Therefore the d-dimer is shown to be an important parameter to be considered in the therapeutic counseling of severe forms of PID.

The innate immune response to secondary peritonitis

Secondary peritonitis continues to cause high morbidity and mortality despite improvements in medical and surgical therapy. This review combines data from published literature, focusing on molecular patterns of inflammation in pathophysiology and prognosis during peritonitis. Orchestration of the innate immune response is essential. To clear the microbial infection, activation and attraction of leukocytes are essential and beneficial, just like the expression of inflammatory cytokines. Exaggeration of these inflammatory systems leads to tissue damage and organ failure. Nonsurvivors have increased proinflammation, complement activation, coagulation, and chemotaxis. In these patients, anti-inflammatory systems are decreased in blood and lungs, whereas the abdominal compartment shows decreased neutrophil activation and decreased or stationary chemokine and cytokine levels. A later down-regulation of proinflammatory mediators with concomitant overexpression of anti-inflammatory mediators leads to immunoparalysis and failure to clear residual bacterial load, resulting in the occurrence of superimposed infections. Thus, in patients with adverse outcome, the inflammatory reaction is no longer contained within the abdomen, and the inflammatory response has shifted to other compartments. For the understanding of the host response to secondary peritonitis, it is essential to realize that the defense systems presumably are expressed differently and, in part, autonomously in different compartments.

Antithrombin levels, morbidity, and mortality in a surgical intensive care unit

BACKGROUND

Antithrombin (AT) levels have been suggested as being predictive of outcome in intensive care unit (ICU) patients with septic shock. We investigated the time course of AT levels in a surgical ICU and tested the hypothesis that AT levels may be associated with morbidity and increased mortality rates in a cohort of surgical ICU patients.

METHODS

Three-hundred-twenty-seven consecutive patients admitted to the ICU with an estimated length of stay more than 48 h were included. AT levels were measured daily.

RESULTS

On admission to the ICU, AT levels were below the lower limit of normal in 84.1% (n = 275) of patients and increased significantly by 48 h after admission to reach normal values by the 7th ICU day in patients who never had sepsis (n = 208). This increase in AT levels was delayed in patients with sepsis. Patients with severe sepsis (n = 55) had consistently lower AT levels compared with other patients. Patients with lower AT levels were more likely to need blood products and had a greater maximum degree of organ dysfunction in the ICU than did other patients. The ICU length of stay was similar, regardless of the AT level on admission. Admission AT levels were not associated with increased ICU mortality in a multivariable analysis.

CONCLUSIONS

AT levels are low on admission to the ICU, regardless of the presence of sepsis. Although associated with the degree of organ dysfunction and the severity of sepsis, AT levels were not independently associated with worse outcome in this group of surgical ICU patients.

Variables associated with positive findings at relaparotomy in patients with secondary peritonitis

OBJECTIVE

The decision whether and when to perform a relaparotomy in secondary peritonitis is largely subjective and based on professional experience. No existing scoring system aids in this decisional process. Our aim was to search for variables that could predict positive findings at relaparotomy.

DESIGN

Retrospective, clinical study.

SETTING

Tertiary university hospital.

PATIENTS

Two hundred and nineteen patients of a consecutive series who underwent an emergency laparotomy for secondary peritonitis.

INTERVENTIONS

None. Sequential prediction models were constructed by accumulation of clinical information in chronological order using logistic regression to determine the strength of association between predictive variables and positive findings at relaparotomy outcome. Positive findings were defined as persistent peritonitis or a new infectious focus at relaparotomy.

MEASUREMENTS AND MAIN RESULTS

Relaparotomy (planned or on demand) for secondary peritonitis was performed in 117 of 219 patients (53%), yielding either positive (n=62) or negative (n=55) findings. Discriminatory power for positive findings at relaparotomy improved in the successive (multivariate) models: general patient characteristics (area under the curve, 0.60; 95% confidence interval, 0.52-0.68), adding peritonitis-related variables (area under the curve, 0.73; 95% confidence interval, 0.66-0.80), adding operation-related variables (area under the curve, 0.74; 95% confidence interval, 0.67-0.81), and adding postoperative variables (area under the curve, 0.87; 95% confidence interval, 0.82-0.92). Bootstrap resampling reduced the areas under the curve of the subsequent models only slightly. Sensitivity and specificity of the final model were 82% and 76%, respectively, at a total error rate of 16%. One preoperative predictor and five postoperative predictors significantly increased the need for relaparotomy: younger age, decreased hemoglobin levels, temperature>39 degrees C, lower Pao2/Fio2 ratio, increased heart rate, and increased sodium levels.

CONCLUSIONS

These data suggest that the causes of secondary peritonitis and findings at emergency laparotomy for peritonitis are poor indicators for whether patients will need a relaparotomy. Factors indicative of progressive or persistent organ failure during early postoperative follow-up are the best indicators for ongoing infection and associated positive findings at relaparotomy.

Infections in the Equine Abdomen and Pelvis: Perirectal Abscesses, Umbilical Infections, and Peritonitis

This article addresses the pathophysiology, diagnosis, management, and prognosis of several different infections within the equine abdomen and pelvic region. The latest advances in the diagnosis and treatment of perirectal abscesses, umbilical infections, and local and diffuse peritonitis are discussed. Emphasis is placed on recent advances in diagnostics and therapeutics with reference to human literature that may be useful in equine practice.

Sepsis progression and outcome: a dynamical model

Background

Sepsis (bloodstream infection) is the leading cause of death in non-surgical intensive care units. It is diagnosed in 750,000 US patients per annum, and has high mortality. Current understanding of sepsis is predominately observational and correlational, with only a partial and incomplete understanding of the physiological dynamics underlying the syndrome. There exists a need for dynamical models of sepsis progression, based upon basic physiologic principles, which could eventually guide hourly treatment decisions.

Results

We present an initial mathematical model of sepsis, based on metabolic rate theory that links basic vascular and immunological dynamics. The model includes the rate of vascular circulation, a surrogate for the metabolic rate that is mechanistically associated with disease progression. We use the mass-specific rate of blood circulation (SRBC), a correlate of the body mass index, to build a differential equation model of circulation, infection, organ damage, and recovery. This introduces a vascular component into an infectious disease model that describes the interaction between a pathogen and the adaptive immune system.

Conclusion

The model predicts that deviations from normal SRBC correlate with disease progression and adverse outcome. We compare the predictions with population mortality data from cardiovascular disease and cancer and show that deviations from normal SRBC correlate with higher mortality rates.