The predisposition, infection, response and organ failure (Piro) sepsis classification system: results of hospital mortality using a novel concept and methodological approach

Pathophysiology and management of liver cirrhosis: from portal hypertension to acute-on-chronic liver failure

Cirrhosis transcends various progressive stages from compensation to decompensation driven by the severity of portal hypertension. The downstream effect of increasing portal hypertension severity leads to various pathophysiological pathways, which result in the cardinal complications of cirrhosis, including ascites, variceal hemorrhage, and hepatic encephalopathy. Additionally, the severity of portal hypertension is the central driver for further advanced complications of hyperdynamic circulation, hepatorenal syndrome, and cirrhotic cardiomyopathy. The management of these individual complications has specific nuances which have undergone significant developments. In contrast to the classical natural history of cirrhosis and its complications which follows an insidious trajectory, acute-on-chronic failure (ACLF) leads to a rapidly downhill course with high short-term mortality unless intervened at the early stages. The management of ACLF involves specific interventions, which have quickly evolved in recent years. In this review, we focus on complications of portal hypertension and delve into an approach toward ACLF.

Predicting Sepsis Mortality in a Population-Based National Database: Machine Learning Approach

BACKGROUND

Although machine learning (ML) algorithms have been applied to point-of-care sepsis prognostication, ML has not been used to predict sepsis mortality in an administrative database. Therefore, we examined the performance of common ML algorithms in predicting sepsis mortality in adult patients with sepsis and compared it with that of the conventional context knowledge-based logistic regression approach.

OBJECTIVE

The aim of this study is to examine the performance of common ML algorithms in predicting sepsis mortality in adult patients with sepsis and compare it with that of the conventional context knowledge-based logistic regression approach.

METHODS

We examined inpatient admissions for sepsis in the US National Inpatient Sample using hospitalizations in 2010-2013 as the training data set. We developed four ML models to predict in-hospital mortality: logistic regression with least absolute shrinkage and selection operator regularization, random forest, gradient-boosted decision tree, and deep neural network. To estimate their performance, we compared our models with the Super Learner model. Using hospitalizations in 2014 as the testing data set, we examined the models' area under the receiver operating characteristic curve (AUC), confusion matrix results, and net reclassification improvement.

RESULTS

Hospitalizations of 923,759 adults were included in the analysis. Compared with the reference logistic regression (AUC: 0.786, 95% CI 0.783-0.788), all ML models showed superior discriminative ability (P<.001), including logistic regression with least absolute shrinkage and selection operator regularization (AUC: 0.878, 95% CI 0.876-0.879), random forest (AUC: 0.878, 95% CI 0.877-0.880), xgboost (AUC: 0.888, 95% CI 0.886-0.889), and neural network (AUC: 0.893, 95% CI 0.891-0.895). All 4 ML models showed higher sensitivity, specificity, positive predictive value, and negative predictive value compared with the reference logistic regression model (P<.001). We obtained similar results from the Super Learner model (AUC: 0.883, 95% CI 0.881-0.885).

CONCLUSIONS

ML approaches can improve sensitivity, specificity, positive predictive value, negative predictive value, discrimination, and calibration in predicting in-hospital mortality in patients hospitalized with sepsis in the United States. These models need further validation and could be applied to develop more accurate models to compare risk-standardized mortality rates across hospitals and geographic regions, paving the way for research and policy initiatives studying disparities in sepsis care.

Prospective international validation of the predisposition, infection, response and organ dysfunction (PIRO) clinical staging system among intensive care and general ward patients

Background

Stratifying patients with sepsis was the basis of the predisposition, infection, response and organ dysfunction (PIRO) concept, an attempt to resolve the heterogeneity in treatment response. The purpose of this study is to perform an independent validation of the PIRO staging system in an international cohort and explore its utility in the identification of patients in whom time to antibiotic treatment is particularly important.

Methods

Prospective international cohort study, conducted over a 6-month period in five Portuguese hospitals and one Australian institution. All consecutive adult patients admitted to selected wards or the intensive care, with infections that met the CDC criteria for lower respiratory tract, urinary, intra-abdominal and bloodstream infections were included.

Results

There were 1638 patients included in the study. Patients who died in hospital presented with a higher PIRO score (10 ± 3 vs 8 ± 4, p < 0.001). The observed mortality was 3%, 15%, 24% and 34% in stage I, II, III and IV, respectively, which was within the predicted intervals of the original model, except for stage IV patients that presented a lower mortality. The hospital survival rate was 84%. The application of the PIRO staging system to the validation cohort resulted in a positive predictive value of 97% for stage I, 91% for stage II, 85% for stage III and 66% for stage IV. The area under the receiver operating characteristics curve (AUROC) was 0.75 for the all cohort and 0.70 if only patients with bacteremia were considered. Patients in stage III and IV who did not have antibiotic therapy administered within the desired time frame had higher mortality rate than those who have timely administration of antibiotic.

Conclusions

To our knowledge, this is the first external validation of this PIRO staging system and it performed well on different patient wards within the hospital and in different types of hospitals. Future studies could apply the PIRO system to decision-making about specific therapeutic interventions and enrollment in clinical trials based on disease stage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00966-7.

Validation of the Predisposition Infection Response Organ (PIRO) dysfunction score for the prognostic stratification of patients with sepsis in the Emergency Department

OBJECTIVE

There are many different methods for computing the Predisposition Infection Response Organ (PIRO) dysfunction score. We compared three PIRO methods (PIRO1 (Howell), PIRO2 (Rubulotta) and PIRO3 (Rathour)) for the stratification of mortality and high level of care admission in septic patients arriving at the Emergency Department (ED) of an Italian Hospital.

DESIGN, SETTING AND PARTICIPANTS

We prospectively collected clinical data of 470 patients admitted due to infection in the ED to compute PIRO according to three different methods. We tested PIRO variables for the prediction of mortality in the univariate analysis. Calculation and comparison were made of the area under the receiver operating curve (AUC) for the three PIRO methods, SOFA and qSOFA.

RESULTS

Most of the variables included in PIRO were related to mortality in the univariate analysis. Increased PIRO scores were related to higher mortality. In relation to mortality, PIRO 1 performed better than PIRO2 at 30 d ((AUC 0.77 (0.716-0.824) vs. AUC 0.699 (0.64-0.758) (p=0.03) and similarly at 60 d (AUC 0.767 (0.715-0.819) vs AUC 0.709 (0.656-0.763)(p=0.55)); PIRO1 performed similarly to PIRO3 (AUC 0.765 (0.71-0.82) at 30 d, AUC 0.754 (0.701-0.806) at 60 d, p=ns). Both PIRO1 and PIRO3 were as good as SOFA referred to mortality (AUC 0.758 (0.699, 0.816) at 30 d vs. AUC 0.738 (0.681, 0.795) at 60 d; p=ns). For high level of care admission, PIRO proved inferior to SOFA.

CONCLUSIONS

We support the use of PIRO1, which combines ease of use and the best performance referred to mortality over the short term. PIRO2 proved to be less accurate and more complex to use, suffering from missing microbiological data in the ED setting.

A critical appraisal of the prognostic predictive models for patients with sepsis: Which model can be applied in clinical practice?

BACKGROUND

Sepsis is associated with high mortality and predictive models can help in clinical decision-making. The objective of this study was to carry out a systematic review of these models.

METHODS

In 2019, we conducted a systematic review in MEDLINE and EMBASE (CDR42018111121:PROSPERO) of articles that developed predictive models for mortality in septic patients (inclusion criteria). We followed the CHARMS recommendations (Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies), extracting the information from its 11 domains (Source of data, Participants, etc). We determined the risk of bias and applicability (participants, outcome, predictors and analysis) through PROBAST (Prediction model Risk Of Bias ASsessment Tool).

RESULTS

A total of 14 studies were included. In the CHARMS extraction, the models found showed great variability in its 11 domains. Regarding the PROBAST checklist, only one article had an unclear risk of bias as it did not indicate how missing data were handled while the others all had a high risk of bias. This was mainly due to the statistical analysis (inadequate sample size, handling of continuous predictors, missing data and selection of predictors), since 13 studies had a high risk of bias. Applicability was satisfactory in six articles. Most of the models integrate predictors from routine clinical practice. Discrimination and calibration were assessed for almost all the models, with the area under the ROC curve ranging from 0.59 to 0.955 and no lack of calibration. Only three models were externally validated and their maximum discrimination values in the derivation were from 0.712 and 0.84. One of them (Osborn) had undergone multiple validation studies.

DISCUSSION

Despite most of the studies showing a high risk of bias, we very cautiously recommend applying the Osborn model, as this has been externally validated various times.

Validation of the Predisposition Infection Response Organ (PIRO) dysfunction score for the prognostic stratification of patients with sepsis in the Emergency Department

OBJECTIVE

There are many different methods for computing the Predisposition Infection Response Organ (PIRO) dysfunction score. We compared three PIRO methods (PIRO1 (Howell), PIRO2 (Rubulotta) and PIRO3 (Rathour)) for the stratification of mortality and high level of care admission in septic patients arriving at the Emergency Department (ED) of an Italian Hospital.

DESIGN, SETTING AND PARTICIPANTS

We prospectively collected clinical data of 470 patients admitted due to infection in the ED to compute PIRO according to three different methods. We tested PIRO variables for the prediction of mortality in the univariate analysis. Calculation and comparison were made of the area under the receiver operating curve (AUC) for the three PIRO methods, SOFA and qSOFA.

RESULTS

Most of the variables included in PIRO were related to mortality in the univariate analysis. Increased PIRO scores were related to higher mortality. In relation to mortality, PIRO 1 performed better than PIRO2 at 30 d ((AUC 0.77 (0.716-0.824) vs. AUC 0.699 (0.64-0.758) (p=0.03) and similarly at 60 d (AUC 0.767 (0.715-0.819) vs AUC 0.709 (0.656-0.763)(p=0.55)); PIRO1 performed similarly to PIRO3 (AUC 0.765 (0.71-0.82) at 30 d, AUC 0.754 (0.701-0.806) at 60 d, p=ns). Both PIRO1 and PIRO3 were as good as SOFA referred to mortality (AUC 0.758 (0.699, 0.816) at 30 d vs. AUC 0.738 (0.681, 0.795) at 60 d; p=ns). For high level of care admission, PIRO proved inferior to SOFA.

CONCLUSIONS

We support the use of PIRO1, which combines ease of use and the best performance referred to mortality over the short term. PIRO2 proved to be less accurate and more complex to use, suffering from missing microbiological data in the ED setting.

Canine parvovirus: a predicting canine model for sepsis

BACKGROUND

Sepsis is a severe condition associated with high prevalence and mortality rates. Parvovirus enteritis is a predisposing factor for sepsis, as it promotes intestinal bacterial translocation and severe immunosuppression. This makes dogs infected by parvovirus a suitable study population as far as sepsis is concerned. The main objective of the present study was to evaluate the differences between two sets of SIRS (Systemic Inflammatory Response Syndrome) criteria in outcome prediction: SIRS 1991 and SIRS 2001. The possibility of stratifying and classifying septic dogs was assessed using a proposed animal adapted PIRO (Predisposition, Infection, Response and Organ dysfunction) scoring system.

RESULTS

The 72 dogs enrolled in this study were scored for each of the PIRO elements, except for Infection, as all were considered to have the same infection score, and subjected to two sets of SIRS criteria, in order to measure their correlation with the outcome. Concerning SIRS criteria, it was found that the proposed alterations on SIRS 2001 (capillary refill time or mucous membrane colour alteration) were significantly associated with the outcome (OR = 4.09, p < 0.05), contrasting with the 1991 SIRS criteria (p = 0.352) that did not correlate with the outcome. No significant statistical association was found between Predisposition (p = 1), Response (p = 0.1135), Organ dysfunction (p = 0.1135), total PIRO score (p = 0.093) and outcome. To explore the possibility of using the SIRS criteria as a fast decision-making tool, a Fast-and-Frugal tree (FFT) was created with a sensitivity of 92% and a specificity of 29%.

CONCLUSION

These results suggest that increasing the SIRS criteria specificity may improve their prognostic value and their clinical usefulness. In order to improve the proposed PIRO scoring system outcome prediction ability, more specific criteria should be added, mainly inflammatory and organ dysfunction biomarkers.

Association between site of infection and in-hospital mortality in patients with sepsis admitted to emergency departments of tertiary hospitals in Medellin, Colombia

Objective

To determine the association between the primary site of infection and in-hospital mortality as the main outcome, or the need for admission to the intensive care unit as a secondary outcome, in patients with sepsis admitted to the emergency department.

Methods

This was a secondary analysis of a multicenter prospective cohort. Patients included in the study were older than 18 years with a diagnosis of severe sepsis or septic shock who were admitted to the emergency departments of three tertiary care hospitals. Of the 5022 eligible participants, 2510 were included. Multiple logistic regression analysis was performed for mortality.

Results

The most common site of infection was the urinary tract, present in 27.8% of the cases, followed by pneumonia (27.5%) and intra-abdominal focus (10.8%). In 5.4% of the cases, no definite site of infection was identified on admission. Logistic regression revealed a significant association between the following sites of infection and in-hospital mortality when using the urinary infection group as a reference: pneumonia (OR 3.4; 95%CI, 2.2 - 5.2; p < 0.001), skin and soft tissues (OR 2.6; 95%CI, 1.4 - 5.0; p = 0.003), bloodstream (OR 2.0; 95%CI, 1.1 - 3.6; p = 0.018), without specific focus (OR 2.0; 95%CI, 1.1 - 3.8; p = 0.028), and intra-abdominal focus (OR 1.9; 95%CI, 1.1 - 3.3; p = 0.024).

Conclusions

There is a significant association between the different sites of infection and in-hospital mortality or the need for admission to an intensive care unit in patients with sepsis or septic shock. Urinary tract infection shows the lowest risk, which should be considered in prognostic models of these conditions.

Acute-on-chronic liver failure: consensus recommendations of the Asian Pacific association for the study of the liver (APASL): an update

The first consensus report of the working party of the Asian Pacific Association for the Study of the Liver (APASL) set up in 2004 on acute-on-chronic liver failure (ACLF) was published in 2009. With international groups volunteering to join, the "APASL ACLF Research Consortium (AARC)" was formed in 2012, which continued to collect prospective ACLF patient data. Based on the prospective data analysis of nearly 1400 patients, the AARC consensus was published in 2014. In the past nearly four-and-a-half years, the AARC database has been enriched to about 5200 cases by major hepatology centers across Asia. The data published during the interim period were carefully analyzed and areas of contention and new developments in the field of ACLF were prioritized in a systematic manner. The AARC database was also approached for answering some of the issues where published data were limited, such as liver failure grading, its impact on the 'Golden Therapeutic Window', extrahepatic organ dysfunction and failure, development of sepsis, distinctive features of acute decompensation from ACLF and pediatric ACLF and the issues were analyzed. These initiatives concluded in a two-day meeting in October 2018 at New Delhi with finalization of the new AARC consensus. Only those statements, which were based on evidence using the Grade System and were unanimously recommended, were accepted. Finalized statements were again circulated to all the experts and subsequently presented at the AARC investigators meeting at the AASLD in November 2018. The suggestions from the experts were used to revise and finalize the consensus. After detailed deliberations and data analysis, the original definition of ACLF was found to withstand the test of time and be able to identify a homogenous group of patients presenting with liver failure. New management options including the algorithms for the management of coagulation disorders, renal replacement therapy, sepsis, variceal bleed, antivirals and criteria for liver transplantation for ACLF patients were proposed. The final consensus statements along with the relevant background information and areas requiring future studies are presented here.

A Comparative Review of Equine SIRS, Sepsis, and Neutrophils

The most recent definition of sepsis in human medicine can be summarized as organ dysfunction caused by a dysregulated host response to infection. In equine medicine, although no consensus definition is available, sepsis is commonly described as a dysregulated host systemic inflammatory response to infection. Defense against host infection is the primary role of innate immune cells known as neutrophils. Neutrophils also contribute to host injury during sepsis, making them important potential targets for sepsis prevention, diagnosis, and treatment. This review will present both historical and updated perspectives on the systemic inflammatory response (SIRS) and sepsis; it will also discuss the impact of sepsis on neutrophils, and the impact of neutrophils during sepsis. Future identification of clinically relevant sepsis diagnosis and therapy depends on a more thorough understanding of disease pathogenesis across species. To gain this understanding, there is a critical need for research that utilizes a clearly defined, and consistently applied, classification system for patients diagnosed with, and at risk of developing, sepsis.

Comparison of severity score models based on different sepsis definitions to predict in-hospital mortality among sepsis patients in the Intensive Care Unit

OBJECTIVE

A comparison is made of the accuracy between severity models, based on different sepsis definitions (systemic inflammatory response syndrome (SIRS), predisposition, insult, response, organ dysfunction (PIRO), and sequential organ failure assessment (SOFA) concepts), in predicting outcomes among sepsis patients.

DESIGN

A retrospective study was carried out.

SETTING

The study was conducted in the Intensive Care Unit (ICU) of a university teaching hospital.

PATIENTS

Septic patients admitted to the ICU during 2007-2016.

MAIN VARIABLES OF INTEREST

The primary outcome was in-hospital mortality, with ICU mortality being the secondary outcome.

RESULTS

A total of 2152 septic patient were identified, with ICU and in-hospital mortality rates of 33.3% and 45.9%, respectively. The Moreno PIRO (AUC, 95%CI) (0.835; 0.818-0.852) showed the highest discriminating capacity, followed by SOFA (0.828; 0.811-0.846), qSOFA (0.792; 0.775-0.809), Rubulotta PIRO (0.708; 0.687-0.730), Howell PIRO (0.706; 0.685-0.728) and SIRS (0.578; 0.556-0.600). The AUC of the SOFA score was comparable to that of the Moreno PIRO (p=0.43), though the AUCs of both of these scores were significantly higher than those of the other scores (p<0.001 for all other comparisons). However, the SOFA score showed the best discriminating capacity in predicting ICU mortality (0.838; 0.820-0.855), followed by Moreno PIRO (0.804; 0.785-0.823) and qSOFA (0.787; 0.770-0.805). The accuracy of the qSOFA in predicting ICU mortality was comparable to that of the Moreno PIRO score (p=0.15).

CONCLUSION

The SOFA score and Moreno PIRO score showed the best accuracy in predicting in-hospital mortality among septic patients admitted to the ICU.

Derivation of Novel Risk Prediction Scores for Community-Acquired Sepsis and Severe Sepsis

OBJECTIVE

We sought to derive and internally validate a Sepsis Risk Score and a Severe Sepsis Risk Score predicting future sepsis and severe sepsis events among community-dwelling adults.

DESIGN

National population-based cohort.

SETTING

United States.

SUBJECTS

A total of 30,239 community-dwelling adults 45 years old or older in the national REasons for Geographic And Racial Differences in Stroke cohort.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Over a median of 6.6 years (interquartile range, 5.1-8.1 yr) of follow-up, there were 1,532 first sepsis (prevalence 8.3 per 1,000 person-years) and 1,151 first severe sepsis (6.2 per 1,000 person-years) events. Risk factors in the best derived Sepsis Risk Score and Severe Sepsis Risk Score included chronic lung disease, age 75 years or older, peripheral artery disease, diabetes, tobacco use, white race, stroke, atrial fibrillation, coronary artery disease, obesity, hypertension, deep vein thrombosis, male sex, high-sensitivity C-reactive protein greater than 3.0 mg/dL, cystatin C ≥1.11 mg/dL, estimated glomerular filtration rate less than 60 mL/min/1.73 m, and albumin-to-creatinine ratio protein greater than 30 μg/mg. Sepsis Risk Score risk categories were very low (0-3 points; 2.3 events per 1,000 person-years), low (4-6; 4.1), medium (7-9; 6.5), high (10-12; 9.7), and very high (13-38; 21.1). Severe Sepsis Risk Score risk categories were very low (0-5 points; 1.5 events per 1,000 person-years), low (6-9; 3.4), medium (10-13; 6.7), high (14-17; 9.9), and very high (18-45; 22.1). The Sepsis Risk Score and Severe Sepsis Risk Score exhibited good discrimination (bootstrapped C index, 0.703 and 0.742) and calibration (p = 0.65 and 0.06).

CONCLUSIONS

The Sepsis Risk Score and Severe Sepsis Risk Score predict 10-year sepsis and severe sepsis risk among community-dwelling adults and may aid in sepsis prevention or mitigation efforts.

"Neo-PIRO": Introducing a Novel Grading System for Surgical Infections of Neonates

Introduction:

Quantification of surgical sepsis was never done beyond superficial, subfascial, and deep surgical site infection (SSI). Invasive surgical sepsis with systemic manifestation has not been tried to be quantified in general and pediatric surgery in particular. Hence, this attempts to develop a novel grading system to quantify neonatal surgical infections.

Materials and Methods:

Predisposing factors, infection, response, and organ failure (PIRO) is being used in critical care institutions for medical sepsis; it was modified with neonate-specific surgical parameters. Authors have developed a grading of these parameters into Grade I, II, and III.

Results:

A blinded statistical test was performed and results were put to test. Extended Mantel–Haenszel Chi-square test validated linear relationship with grade and outcome, hospital stay, deep SSI, and organ dysfunction. Analysis of variance also showed the significant relationship of changing trends in grade and outcome. (1) Higher the grade indicated the probability of death. (2) Grade I patients had less duration of hospital stay compared to Grade II and III (P = 0.04). (3) The requirement of organ support and SSI were also more in Grade III. (4) Grade I patients had less increase in trends compared to Grade II and III (F = 4.86). Authors therefore feel Neo-PIRO seems to be the first scoring system that shows a linear relationship between scores and grade.

Conclusion:

Neo-PIRO is a novel grading system with surgical neonate-specific parameters. Future versions to include molecular parameters, as well as parameters selected by regression analysis.

Challenges in Sepsis Care: New Sepsis Definitions and Fluid Resuscitation Beyond the Central Venous Pressure

There are two important recent changes in sepsis care. The first key change is the 2016 Sepsis-3 definitions from the recent consensus workgroup with new sepsis and septic shock definitions. Useful tools for assessing patients that have a greater risk of mortality include Sequential Organ Failure Assessment (SOFA) in intensive care units and quick SOFA outside intensive care units. The second change involves management of fluid resuscitation and measures of volume responsiveness. Measures such as blood pressure and central venous pressure are not reliable. Fluid challenges and responsiveness should be based on stroke volume change of greater than 10%.

Immunotherapy of Sepsis: Blind Alley or Call for Personalized Assessment?

Sepsis is the most frequent cause of death in noncoronary intensive care units. In the past 10 years, progress has been made in the early identification of septic patients and their treatment. These improvements in support and therapy mean that mortality is gradually decreasing, however, the rate of death from sepsis remains unacceptably high. Immunotherapy is not currently part of the routine treatment of sepsis. Despite experimental successes, the administration of agents to block the effect of sepsis mediators failed to show evidence for improved outcome in a multitude of clinical trials. The following survey summarizes the current knowledge and results of clinical trials on the immunotherapy of sepsis and describes the limitations of our knowledge of the pathogenesis of sepsis. Administration of immunomodulatory drugs should be linked to the current immune status assessed by both clinical and molecular patterns. Thus, a careful daily review of the patient's immune status needs to be introduced into routine clinical practice giving the opportunity for effective and tailored use of immunomodulatory therapy.

Site of infection and mortality in patients with severe sepsis or septic shock. A cohort study of patients admitted to a Danish general intensive care unit

BACKGROUND

The search for the site of infection has high priority in patients with severe sepsis and septic shock. However, it is questionable whether mortality is associated with the specific site of infection in patients admitted to an intensive care unit (ICU). Therefore, the 30-day and 90-day mortalities in ICU patients admitted with suspected or confirmed community-acquired infection were studied.

METHODS

A retrospective cohort study was conducted, including all adult patients admitted to a multi-specialty tertiary ICU with severe sepsis or septic shock from November 2008 to October 2010. The site of infection was classified according to criteria set for healthcare associated infections and infections in the acute care setting by Centers for Disease Control and Prevention (CDC). Kaplan-Meier curves and Poisson regression analysis were used to evaluate the association between site of infection and 30- and 90-day all-cause mortality, adjusting for age, sex and comorbidities.

RESULTS

Three hundred and eighty-eight patients were included. One or more comorbidities were present in 76% of patients. Across all sites of infection, there were more patients with septic shock than patients with severe sepsis. The most frequent site of infection was pneumonia, followed by gastrointestinal infection. Urinary tract infection was found to be an independent predictor of mortality among septic ICU patients when adjusting for sex, age and comorbidities.

CONCLUSIONS

The results suggest that identification of correct site of infection is important in the management of severe sepsis and septic shock.

PIRO concept: staging of sepsis

Introduction:

Sepsis is common presenting illness to the emergency services and one of the leading causes of hospital mortality. Researchers and clinicians have realized that the systemic inflammatory response syndrome concept for defining sepsis is less useful and lacks specificity. The predisposition, infection (or insult), response and organ dysfunction (PIRO) staging of sepsis similar to malignant diseases (TNM staging) might give better information.

Materials and Methods:

A prospective observational study was conducted in emergency medical services attached to medicine department of a tertiary care hospital in Northern India. Patients with age 18 years or more with proven sepsis were included in the first 24 hours of the diagnosis. Two hundred patients were recruited. Multivariate logistic regression analysis was done to assess the factors that predicted in-hospital mortality.

Results:

Two hundred patients with proven sepsis, admitted to the emergency medical services were analysed. Male preponderance was noted (M: F ratio = 1.6:1). Mean age of study cohort was 50.50 ± 16.30 years. Out of 200 patients, 116 (58%) had in-hospital mortality. In multivariate logistic regression analysis, the factors independently associated with in-hospital mortality for predisposition component of PIRO staging were age >70 years, chronic obstructive pulmonary disease, chronic liver disease, cancer and presence of foley's catheter; for infection/insult were pneumonia, urinary tract infection and meningitis/encephalitis; for response variable were tachypnea (respiratory rate >20/minute) and bandemia (band >5%). Organ dysfunction variables associated with hospital mortality were systolic blood pressure <90mm Hg, prolonged activated partial thromboplastin time, raised serum creatinine, partial pressure of oxygen in arterial blood/fraction of inspired oxygen (PaO₂/FiO₂) ratio <300, decreased urine output in first two hours of emergency presentation and Glasgow coma scale ≤9. Each of the components of PIRO had good predictive capability for in-hospital mortality but the total score was more accurate than the individual score and increasing PIRO score was associated with higher in-hospital mortality. The area under receiver operating characteristic curve for cumulative PIRO staging system as a predictor of in-hospital mortality was 0.94.

Conclusion:

This study finds PIRO staging as an important tool to stratify and prognosticate hospitalised patients with sepsis at a tertiary care center. The simplicity of score makes it more practical to be used in busy emergencies as it is based on four easily assessable components.

Innate immunity gene expression changes in critically ill patients with sepsis and disease-related malnutrition

The aim of this study was an attempt to determine whether the expression of genes involved in innate antibacterial response (TL R2, NOD 1, TRAF6, HMGB 1 and Hsp70) in peripheral blood leukocytes in critically ill patients, may undergo significant changes depending on the severity of the infection and the degree of malnutrition. The study was performed in a group of 128 patients with infections treated in the intensive care and surgical ward. In 103/80.5% of patients, infections had a severe course (sepsis, severe sepsis, septic shock, mechanical ventilation of the lungs). Clinical monitoring included diagnosis of severe infection (according to the criteria of the ACC P/SCC M), assessment of severity of the patient condition and risk of death (APACHE II and SAPS II), nutritional assessment (NRS 2002 and SGA scales) and the observation of the early results of treatment. Gene expression at the mRNA level was analyzed by real-time PCR. The results of the present study indicate that in critically ill patients treated in the IC U there are significant disturbances in the expression of genes associated with innate antimicrobial immunity, which may have a significant impact on the clinical outcome. The expression of these genes varies depending on the severity of the patient condition, severity of infection and nutritional status. Expression disorders of genes belonging to innate antimicrobial immunity should be diagnosed as early as possible, monitored during the treatment and taken into account during early therapeutic treatment (including early nutrition to support the functions of immune cells).

Current views on the mechanisms of immune responses to trauma and infection

According to the World Health Organization, post-traumatic mortality rates are still very high and show an increasing tendency. Disorders of innate immune response that may increase the risk of serious complications play a key role in the immunological system response to trauma and infection. The mechanism of these disorders is multifactorial and is still poorly understood. The changing concepts of systemic inflammatory response syndrome (SIRS) and compensatory anti-inflammatory response syndrome (CARS) early inflammatory response, presented in this work, have been extended to genetic studies. Overexpression of genes and increased production of immune response mediators are among the main causes of multiple organ dysfunction syndrome (MODS). Changes in gene expression detected early after injury precede the occurrence of subsequent complications with a typical clinical picture. Rapid depletion of energy resources leads to immunosuppression and persistent inflammation and immune suppression catabolism syndrome (PICS). Early diagnosis of immune disorders and appropriate nutritional therapy can significantly reduce the incidence of complications, length of hospital stay, and mortality. The study presents the development of knowledge and current views explaining the mechanisms of the immune response to trauma and infection.

Acute-on-chronic liver failure: consensus recommendations of the Asian Pacific Association for the Study of the Liver (APASL) 2014

The first consensus report of the working party of the Asian Pacific Association for the Study of the Liver (APASL) set up in 2004 on acute-on-chronic liver failure (ACLF) was published in 2009. Due to the rapid advancements in the knowledge and available information, a consortium of members from countries across Asia Pacific, "APASL ACLF Research Consortium (AARC)," was formed in 2012. A large cohort of retrospective and prospective data of ACLF patients was collated and followed up in this data base. The current ACLF definition was reassessed based on the new AARC data base. These initiatives were concluded on a 2-day meeting in February 2014 at New Delhi and led to the development of the final AARC consensus. Only those statements which were based on the evidence and were unanimously recommended were accepted. These statements were circulated again to all the experts and subsequently presented at the annual conference of the APASL at Brisbane, on March 14, 2014. The suggestions from the delegates were analyzed by the expert panel, and the modifications in the consensus were made. The final consensus and guidelines document was prepared. After detailed deliberations and data analysis, the original proposed definition was found to withstand the test of time and identify a homogenous group of patients presenting with liver failure. Based on the AARC data, liver failure grading, and its impact on the "Golden therapeutic Window," extra-hepatic organ failure and development of sepsis were analyzed. New management options including the algorithms for the management of coagulation disorders, renal replacement therapy, sepsis, variceal bleed, antivirals, and criteria for liver transplantation for ACLF patients were proposed. The final consensus statements along with the relevant background information are presented here.

The role of obesity in the immune response during sepsis

Background/Objectives:

Sepsis is one of the most important causes of mortality in the developed world, where almost two-thirds of the population suffer from obesity. Therefore, the coexistence of both conditions has become frequent in clinical practice and a growing number of clinical studies attempts to examine the potential effect of obesity on sepsis with controversial results up to now. The present study investigates how obesity influences the immune response of septic patients, by assessing the number and activation state of adipose tissue macrophages, serum and adipose tissue tumor necrosis factor-alpha (TNFα) levels and plasma oxidative stress markers.

Subjects/methods:

The study included 106 patients, divided into four groups (control n=26, obesity n=27, sepsis n=27 and sepsis and obesity n=26). The number of macrophages in subcutaneous and visceral adipose tissue (SAT and VAT) and their subtypes (M1 and M2) were defined with immunohistochemical staining techniques under light microscopy. TNFα mRNA levels were determined in SAT and VAT using real-time reverse transcription-PCR. Serum levels of TNFα were determined with sandwich enzyme-linked immunosorbent assay. Plasma oxidative stress was evaluated using selective biomarkers (thiobarbituric acid-reactive substances (TBARS), protein carbonyls and total antioxidant capacity (TAC)).

Results:

Sepsis increased the total number of macrophages and their M2 subtype in (VAT), whereas obesity did not seem to affect the concentration of macrophages in fat. Obesity increased TNFα mRNA levels (P<0.05) in VAT as well as the plasma TBARS (P<0.001) and protein carbonyls (P<0.001) in septic patients. The plasma TAC levels were decreased and the serum TNFα levels were increased in sepsis although they were not influenced by obesity.

Conclusions:

Obesity is associated with elevated TNFα adipose tissue production and increased oxidative stress biomarkers, promoting the proinflammatory response in septic patients.

Sepsis outside intensive care unit: the other side of the coin

INTRODUCTION

A growing body of evidence points out that a large amount of patients with sepsis are admitted and treated in medical ward (MW). With most of the sepsis studies conducted in intensive care unit (ICU), these patients, older and with more comorbidities have received poor attention. Provided the differences between the two groups of patients, results of diagnostic and therapeutic trials from ICU should not be routinely transferred to MW, where sepsis seems to be at least as common as in ICU.

METHODS

We analyzed clinical trials on novel tools for an early diagnosis of sepsis published in the last two year adopting strict research criteria. Moreover we conducted a target review of the literature on non-invasive monitoring of severe sepsis and septic shock.

RESULTS AND CONCLUSIONS

The combination of innovative and non-invasive tools for sepsis rule in/out, as quick alternatives to blood cultures (gold standard) with bedside integrated ultrasonography could impact triage, diagnosis and prognosis of septic patients managed in MW, preventing ICU admissions, poor outcomes and costly complications, especially in elderly that are usually highly vulnerable to invasive procedures.

Time for a neonatal-specific consensus definition for sepsis

OBJECTIVE

To review the accuracy of the pediatric consensus definition of sepsis in term neonates and to determine the definition of neonatal sepsis used.

STUDY SELECTION

The review focused primarily on pediatric literature relevant to the topic of interest.

CONCLUSIONS

Neonatal sepsis is variably defined based on a number of clinical and laboratory criteria that make the study of this common and devastating condition very difficult. Diagnostic challenges and uncertain disease epidemiology necessarily result from a variable definition of disease. In 2005, intensivists caring for children recognized that as new drugs became available, children would be increasingly studied and thus, pediatric-specific consensus definitions were needed. Pediatric sepsis criteria are not accurate for term neonates and have not been examined in preterm neonates for whom the developmental stage influences aberrations associated with host immune response. Thus, specific consensus definitions for both term and preterm neonates are needed. Such definitions are critical for the interpretation of observational studies, future training of scientists and practitioners, and implementation of clinical trials in neonates.

Barriers to the effective treatment of sepsis: antimicrobial agents, sepsis definitions, and host-directed therapies

Sepsis is a complex clinical syndrome involving both infection and a deleterious host immune response. Antimicrobial agents are key elements of sepsis treatment, yet despite great strides in antimicrobial development in the last decades, sepsis continues to be associated with unacceptably high mortality (~30%). This is the result, on one hand, of the rise of antimicrobial resistant organisms and, on the other hand, of the dearth of effective host-directed immune therapies. A major obstacle to the development of good host-directed therapies is the lack of understanding of the host immune response. The problem is exacerbated by poor nonspecific clinical definitions of disease. Poor definitions have had a profound impact on sepsis research, from epidemiologic studies to the failed clinical trials of host-directed therapies. Therefore, better definitions must be developed to enable advancement in the field.

Risk stratification and prognostic performance of the predisposition, infection, response, and organ dysfunction (PIRO) scoring system in septic patients in the emergency department: a cohort study

Introduction

The predisposition, infection, response and organ dysfunction (PIRO) staging system was designed as a stratification tool to deal with the inherent heterogeneity of septic patients. The present study was conducted to assess the performance of PIRO in predicting multiple organ dysfunction (MOD), intensive care unit (ICU) admission, and 28-day mortality in septic patients in the emergency department (ED), and to compare this scoring system with the Mortality in Emergency Department Sepsis (MEDS) and Acute Physiology and Chronic Health Evaluation (APACHE II) scores.

Methods

Consecutive septic patients (n = 680) admitted to the ED of Beijing Chao-Yang Hospital were enrolled. PIRO, MEDS, and APACHE II scores were calculated for each patient on ED arrival. Organ function was reassessed within 3 days of enrollment. All patients were followed up for 28 days. Outcome criteria were the development of MOD within 3 days, ICU admission or death within 28 days after enrollment. The predictive ability of the four components of PIRO was analyzed separately. Receiver operating characteristic (ROC) curve and logistic regression analysis were used to assess the prognostic and risk stratification value of the scoring systems.

Results

Organ dysfunction independently predicted ICU admission, MOD, and 28-day mortality, with areas under the ROC curve (AUC) of 0.888, 0.851, and 0.816, respectively. The predictive value of predisposition, infection, and response was weaker than that of organ dysfunction. A negative correlation was found between the response component and MOD, as well as mortality. PIRO, MEDS, and APACHE II scores significantly differed between patients who did and did not meet the outcome criteria (P < 0.001). PIRO and APACHE II independently predicted ICU admission and MOD, but MEDS did not. All three systems were independent predictors of 28-day mortality with similar AUC values. The AUC of PIRO was 0.889 for ICU admission, 0.817 for MOD, and 0.744 for 28-day mortality. The AUCs of PIRO were significantly greater than those of APACHE II and MEDS (P < 0.05) in predicting ICU admission and MOD.

Conclusions

The study indicates that PIRO is helpful for risk stratification and prognostic determinations in septic patients in the ED.

The PIRO (predisposition, insult, response, organ dysfunction) model: toward a staging system for acute illness

Multimodal therapy for diseases like cancer has only become practicable following the development of staging systems like the TNM (tumor, nodes, metastases) system. Staging enables the identification of subgroups of patients with a disease who not only have a differing prognosis, but who are also more likely to benefit from a specific therapeutic modality. Critically ill patients represent a highly heterogeneous population for whom multiple therapeutic options are potentially available, each carrying not only the potential for differential benefit, but also the potential for differential harm. The PIRO system (predisposition, insult, response, organ dysfunction) is a template proposal for a staging system for acute illness that incorporates assessment of pre-morbid baseline susceptibility (predisposition), the specific disorder responsible for acute illness (insult), the response of the host to that insult, and the resulting degree of organ dysfunction. However the creation of a valid, robust, and clinically useful system presents significant challenges arising from the complexity of the disease state, the lack of a clear phenotype, the confounding influence of the effects of therapy and of cultural and socio-economic factors, and the relatively low profile of acute illness with clinicians and the general public. This review summarizes the rationale for such a model of illness stratification and the results of preliminary cohort studies testing the concept. It further proposes two strategies for building a staging system, recognizing that this will be a demanding undertaking that will require decades of work.

Evaluation of community-acquired sepsis by PIRO system in the emergency department

The predisposition, infection/insult, response, and organ dysfunction (PIRO) staging system for septic patients allows grouping of heterogeneous patients into homogeneous subgroups. The purposes of this single-center, prospective, observational cohort study were to create a PIRO system for patients with community-acquired sepsis (CAS) presenting to the emergency department (ED) and assess its prognostic and stratification capabilities. Septic patients were enrolled and allocated to derivation (n = 831) or validation (n = 860) cohorts according to their enrollment dates. The derivation cohort was used to identify independent predictors of mortality and create a PIRO system by binary logistic regression analysis, and the prognostic performance of PIRO was investigated in the validation cohort by receiver operator characteristic (ROC) curve. Ten independent predictors of 28-day mortality were identified. The PIRO system combined the components of predisposition (age, chronic obstructive pulmonary disease, hypoalbuminemia), infection (central nervous system infection), response (temperature, procalcitonin), and organ dysfunction (brain natriuretic peptide, troponin I, mean arterial pressure, Glasgow coma scale score). The area under the ROC of PIRO was 0.833 for the derivation cohort and 0.813 for the validation cohort. There was a stepwise increase in 28-day mortality with increasing PIRO score and the differences between the low- (PIRO 0-10), intermediate- (11-20), and high- (>20) risk groups were very significant in both cohorts (p < 0.01). The present study demonstrates that this PIRO system is valuable for prognosis and risk stratification in patients with CAS in the ED.

Predisposition, insult/infection, response and organ dysfunction (PIRO): a pilot clinical staging system for hospital mortality in patients with infection

PURPOSE

To develop a clinical staging system based on the PIRO concept (Predisposition, Infection, RESPONSE and Organ dysfunction) for hospitalized patients with infection.

METHODS

One year prospective cohort study of all hospitalized patients with infection (n = 1035), admitted into a large tertiary care, university hospital. Variables associated with hospital mortality were selected using logistic regressions. Based on the regression coefficients, a score for each PIRO component was developed and a classification tree was used to stratify patients into four stages of increased risk of hospital mortality. The final clinical staging system was then validated using an independent cohort (n = 186).

RESULTS

Factors significantly associated with hospital mortality were • for Predisposition: age, sex, previous antibiotic therapy, chronic hepatic disease, chronic hematologic disease, cancer, atherosclerosis and a Karnofsky index<70; • for Insult/Infection: type of infection • for

RESPONSE

abnormal temperature, tachypnea, hyperglycemia and severity of infection and • for Organ dysfunction: hypotension and SOFA score≥1. The area under the ROC curve (CI95%) for the combined PIRO model as a predictor for mortality was 0.85 (0.82-0.88). Based on the scores for each of the PIRO components and on the cut-offs estimated from the classification tree, patients were stratified into four stages of increased mortality rates: stage I: ≤5%, stage II: 6-20%, stage III: 21-50% and stage IV: >50%. Finally, this new clinical staging system was studied in a validation cohort, which provided similar results (0%, 9%, 31% and 67%, in each stage, respectively).

CONCLUSIONS

Based on the PIRO concept, a new clinical staging system was developed for hospitalized patients with infection, allowing stratification into four stages of increased mortality, using the different scores obtained in Predisposition, RESPONSE, Infection and Organ dysfunction. The proposed system will likely help to define inclusion criteria in clinical trials as well as tailoring individual management plans for patients with infection.