Bedside prediction of mortality from bacteremic sepsis. A dynamic analysis of ICU patients

Autophagy ablation in skeletal muscles worsens sepsis-induced muscle wasting, impairs whole-body metabolism, and decreases survival

Septic patients frequently develop skeletal muscle wasting and weakness, resulting in severe clinical consequences and adverse outcomes. Sepsis triggers sustained induction of autophagy, a key cellular degradative pathway, in skeletal muscles. However, the impact of enhanced autophagy on sepsis-induced muscle dysfunction remains unclear. Using an inducible and muscle-specific Atg7 knockout mouse model (Atg7iSkM-KO), we investigated the functional importance of skeletal muscle autophagy in sepsis using the cecal ligation and puncture model. Atg7iSkM-KO mice exhibited a more severe phenotype in response to sepsis, marked by severe muscle wasting, hypoglycemia, higher ketone levels, and a decreased in survival as compared to mice with intact Atg7. Sepsis and Atg7 deletion resulted in the accumulation of mitochondrial dysfunction, although sepsis did not further worsen mitochondrial dysfunction in Atg7iSkM-KO mice. Overall, our study demonstrates that autophagy inactivation in skeletal muscles triggers significant worsening of sepsis-induced muscle and metabolic dysfunctions and negatively impacts survival.

Exploring Features Contributing to the Early Prediction of Sepsis Using Machine Learning

The increasing availability of electronic health records and administrative data and the adoption of computer-based technologies in healthcare have significantly focused on medical informatics. Sepsis is a time-critical condition with high mortality, yet it is often not identified in a timely fashion. The early detection and diagnosis of sepsis can increase the likelihood of survival and improve long-term outcomes for patients. In this paper, we use SHapley Additive exPlanations (SHAP) analysis to explore the variables most highly associated with developing sepsis in patients and evaluating different supervised learning models for classification. To develop our predictive models, we used the data collected after the first and the fifth hour of admission and evaluated the contribution of different features to the prediction results for both time intervals. The results of our study show that, while there is a high level of missing data during the early stages of admission, this data can be effectively utilized for the early prediction of sepsis. We also found a high level of inconsistency between the contributing features at different stages of admission, which should be considered when developing machine learning models.

Prognostic Effects of Delayed Administration of Antimicrobial Therapy in Older Persons Experiencing Bacteremia With or Without Initial Sepsis Presentations

OBJECTIVES

To investigate the prognostic effects of delayed administration of appropriate antimicrobial therapy (AAT) in older persons experiencing bacteremia with and without initial sepsis syndrome, respectively.

DESIGN

A 4-year multicenter cohort study.

SETTING AND PARTICIPANTS

Older people (≥65 years of age) with community-onset bacteremia in the emergency department (ED) of 3 participating hospitals.

METHODS

Clinical data were retrospectively collected and causative microorganisms were prospectively collected for susceptibilities to determine the period of delayed AAT for each bacteremia episode. Sepsis was defined based on the Sepsis-3 criteria. A multivariable regression model was used to investigate the prognostic effects of delayed AAT, after adjusting independent determinants of 30-day mortality.

RESULTS

Of the total 2357 patients, their median (interquartile range) age was 78 (72-84) years and septic patients accounted for 48.4% (1140 patients) of the overall patients. Compared with nonseptic patients, septic individuals exhibited the shorter period of delayed AAT (median, 2.0 vs 2.5 hours; P < .001), longer hospitalization (median, 11 vs 9 days; P < .001), and higher crude mortality rates at 15 (28.9% vs 2.1%; P < .001) and 30 days (34.6% vs 4.0%; P < .001). In multivariable regression analyses, each hour of delayed AAT resulted in average increases in the 30-day crude mortality rates of 0.38% [adjusted odds ratio (AOR) 1.0038; P < .001), 0.42% (AOR 1.0042; P < .001), and 0.31% (AOR 1.0031; P = .04) among overall, septic, and nonseptic patients, respectively.

CONCLUSIONS AND IMPLICATIONS

For older persons with community-onset bacteremia, irrespective of whether or not patients experiencing initial sepsis presentations, the prognostic impacts of delayed AAT have been evidenced. Notably, because of the longer period of delayed AAT in patients without fulfilling the Sepsis-3, adopting a stricter sepsis definition and/or early bacteremia predictor to avoid delayed AAT and unfavorable prognoses in patients with bacteremia is necessary.

The Utility of Early Warning Score in Adults Presenting With Sepsis in the Emergency Department of a Low Resource Setting

Background

Sepsis is a condition with high mortality and morbidity. Delay in early recognition and prompt management results in higher mortality. There are many clinical scores to identify early sepsis; however, Early Warning Score (EWS) has clinical/physiological parameters that are easy to apply in the ED for timely diagnosis and management. In the present study, we collected information regarding the utilization of EWS in timely identifying the sick patients at triage of a tertiary care center.

Methods

This study was a descriptive cross-sectional investigation conducted in the ED of Aga Khan University Hospital in Karachi, the largest metropolitan city in Pakistan. A total of 240 participants were selected by non-probability convenient sampling after fulfilling the inclusion criteria. Data collected included EWS criteria, demography, length of hospital stay, patient disposition (ward, intensive care or high dependency area), and differentials like sepsis, severe sepsis or septic shock.

Results

A total of 240 patients were enrolled, out of which 139 (57.9%) patients were male, and 101 (42.1%) were female with a mean age of 52.7 ± 15.3 years (range: 18 to 80 years). In this study, the length of stay (LOS) was 2.2 ± 1.1 (range: one to six days), and there was an EWS of 8.2 ± 2.6 (4-15). There were 143 patients in the elderly age group > 50 years (59.6%); however, most elderly presented with sepsis among both age groups. The least affected age group was aged 16 to 30 years, with 23 (9.6%) cases. An EWS >7 is best to detect cases with sepsis or severe sepsis with a sensitivity of 98.5% (95% CI: 92.13 to 99.92) and specificity of 89.57% (95% CI: 82.64 to 93.93). Similarly, the EWS for severe sepsis or septic shock was >9 with a sensitivity of 86.76% (95% CI: 76.72 to 92.88) and specificity of 88.24% (95% CI: 78.47 to 93.92).

Conclusions

This study revealed that the sensitivity and specificity of EWS for the detection of sepsis, severe sepsis and septic shock was found to be high; hence, it could be a valuable and readily useable system for early diagnosis and proper management of sepsis, severe sepsis, and septic shock.

Time-Series Analysis of Laboratory Values in the Context of Long-Term Hospitalized Patient Mortality

OBJECTIVES

Long-term hospitalized patients have a higher risk of adverse outcomes and mortality rate. These patients often rapidly deteriorate, leading to death. We aim to evaluate end-of-life laboratory values time trends among deceased long-term inpatients.

METHODS

Time-stamped laboratory data for adult inpatients who had died in the hospital were extracted. The data were normalized and time-series analysis was performed. The patients were also clustered based on the laboratory result trends.

RESULTS

Laboratory results from 257 patients were evaluated. Significant time trends were observed: serum urea nitrogen, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and potassium increased while platelets and albumin decreased. Most patients showed significant shifts in at least four major laboratory indices within the last week of life.

CONCLUSIONS

In the last week of life in chronically hospitalized patients, an alteration of the physiologic state of the patient occurs that manifests as subtle changes in metabolite levels compared with the patient's baseline.

Bacterial DNA patterns identified using paired-end Illumina sequencing of 16S rRNA genes from whole blood samples of septic patients in the emergency room and intensive care unit

BACKGROUND

Sepsis refers to clinical presentations ranging from mild body dysfunction to multiple organ failure. These clinical symptoms result from a systemic inflammatory response to pathogenic or potentially pathogenic microorganisms present systemically in the bloodstream. Current clinical diagnostics rely on culture enrichment techniques to identify bloodstream infections. However, a positive result is obtained in a minority of cases thereby limiting our knowledge of sepsis microbiology. Previously, a method of saponin treatment of human whole blood combined with a comprehensive bacterial DNA extraction protocol was developed. The results indicated that viable bacteria could be recovered down to 10 CFU/ml using this method. Paired-end Illumina sequencing of the 16S rRNA gene also indicated that the bacterial DNA extraction method enabled recovery of bacterial DNA from spiked blood. This manuscript outlines the application of this method to whole blood samples collected from patients with the clinical presentation of sepsis.

RESULTS

Blood samples from clinically septic patients were obtained with informed consent. Application of the paired-end Illumina 16S rRNA sequencing to saponin treated blood from intensive care unit (ICU) and emergency department (ED) patients indicated that bacterial DNA was present in whole blood. There were three clusters of bacterial DNA profiles which were distinguished based on the distribution of Streptococcus, Staphylococcus, and Gram-negative DNA. The profiles were examined alongside the patient's clinical data and indicated molecular profiling patterns from blood samples had good concordance with the primary source of infection.

CONCLUSIONS

Overall this study identified common bacterial DNA profiles in the blood of septic patients which were often associated with the patients' primary source of infection. These results indicated molecular bacterial DNA profiling could be further developed as a tool for clinical diagnostics for bloodstream infections.

Fever in the Emergency Department Predicts Survival of Patients With Severe Sepsis and Septic Shock Admitted to the ICU

OBJECTIVES

To study the prognostic value of fever in the emergency department in septic patients subsequently admitted to the ICU.

DESIGN

Observational cohort study from the Swedish national quality register for sepsis.

SETTING

Thirty ICU's in Sweden.

PATIENTS

Two thousand two hundred twenty-five adults who were admitted to an ICU within 24 hours of hospital arrival with a diagnosis of severe sepsis or septic shock were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Body temperature was measured and classified according to four categories (< 37°C, 37-38.29°C, 38.3-39.5°C, ≥ 39.5°C). The main outcome was in-hospital mortality. Odds ratios for mortality according to body temperature were estimated using multivariable logistic regression. Subgroup analyses were conducted according to age, sex, underlying comorbidity, and time to given antibiotics. Overall mortality was 25%. More than half of patients had a body temperature below 38.3°C. Mortality was inversely correlated with temperature and decreased, on average, more than 5% points per °C increase, from 50% in those with the lowest temperatures to 9% in those with the highest. Increased body temperature in survivors was also associated with shorter hospital stays. Patients with fever received better quality of care, but the inverse association between body temperature and mortality was robust and remained consistent after adjustment for quality of care measures and other factors that could have confounded the association. Among vital signs, body temperature was best at predicting mortality.

CONCLUSIONS

Contrary to common perceptions and current guidelines for care of critically ill septic patients, increased body temperature in the emergency department was strongly associated with lower mortality and shorter hospital stays in patients with severe sepsis or septic shock subsequently admitted to the ICU.

Fever Is Associated with Reduced, Hypothermia with Increased Mortality in Septic Patients: A Meta-Analysis of Clinical Trials

Background

Sepsis is usually accompanied by changes of body temperature (T_b), but whether fever and hypothermia predict mortality equally or differently is not fully clarified. We aimed to find an association between T_b and mortality in septic patients with meta-analysis of clinical trials.

Methods

We searched the PubMed, EMBASE, and Cochrane Controlled Trials Registry databases (from inception to February 2016). Human studies reporting T_b and mortality of patients with sepsis were included in the analyses. Average T_b with SEM and mortality rate of septic patient groups were extracted by two authors independently.

Results

Forty-two studies reported T_b and mortality ratios in septic patients (n = 10,834). Pearson correlation analysis revealed weak negative linear correlation (R² = 0.2794) between T_b and mortality. With forest plot analysis, we found a 22.2% (CI, 19.2–25.5) mortality rate in septic patients with fever (T_b > 38.0°C), which was higher, 31.2% (CI, 25.7–37.3), in normothermic patients, and it was the highest, 47.3% (CI, 38.9–55.7), in hypothermic patients (T_b < 36.0°C). Meta-regression analysis showed strong negative linear correlation between T_b and mortality rate (regression coefficient: -0.4318; P < 0.001). Mean T_b of the patients was higher in the lowest mortality quartile than in the highest: 38.1°C (CI, 37.9–38.4) vs 37.1°C (CI, 36.7–37.4).

Conclusions

Deep T_b shows negative correlation with the clinical outcome in sepsis. Fever predicts lower, while hypothermia higher mortality rates compared with normal T_b. Septic patients with the lowest (< 25%) chance of mortality have higher T_b than those with the highest chance (> 75%).

The Practice Guidelines for Primary Care of Acute Abdomen 2015

BACKGROUND

Since acute abdomen requires accurate diagnosis and treatment within a particular time limit to prevent mortality, the Japanese Society for Abdominal Emergency Medicine in collaboration with four other medical societies launched the Practice Guidelines for Primary Care of Acute Abdomen that were the first English guidelines in the world for the management of acute abdomen. Here we provide the highlights of these guidelines [all clinical questions (CQs) and recommendations are shown in supplementary information].

METHODS

A systematic and comprehensive evaluation of the evidence for epidemiology, diagnosis, differential diagnosis, and primary treatment for acute abdomen was performed to develop the Practice Guidelines for Primary Care of Acute Abdomen 2015. Because many types of pathophysiological events underlie acute abdomen, these guidelines cover the primary care of adult patients with nontraumatic acute abdomen.

RESULTS

A total of 108 questions based on 9 subject areas were used to compile 113 recommendations. The subject areas included definition, epidemiology, history taking, physical examination, laboratory test, imaging studies, differential diagnosis, initial treatment, and education. Japanese medical circumstances were considered for grading the recommendations to assure useful information. The two-step methods for the initial management of acute abdomen were proposed. Early use of transfusion and analgesia, particularly intravenous acetaminophen, were recommended.

CONCLUSIONS

The Practice Guidelines for Primary Care of Acute Abdomen 2015 have been prepared as the first evidence-based guidelines for the management of acute abdomen. We hope that these guidelines contribute to clinical practice and improve the primary care and prognosis of patients with acute abdomen.

A Fever in Acute Aortic Dissection is Caused by Endogenous Mediators that Influence the Extrinsic Coagulation Pathway and Do Not Elevate Procalcitonin

Objective A fever is observed in approximately one-third of cases of acute aortic dissection (AAD); however, the causes remain unclear. We investigated the mechanism of a fever in AAD by measuring the serum concentrations of inflammatory markers, mediators of coagulation and fibrinolysis, and procalcitonin, a marker of bacterial infection. Methods We retrospectively studied 43 patients with medically treated AAD without apparent infection. Patients were divided into those with (Group A; n=19) and without (Group B; n=24) a maximum body temperature >38°C. We established which patients fulfilled the criteria for systemic inflammatory response syndrome (SIRS), and its relationship with a fever was examined. Mediators of inflammation, coagulation and fibrinolysis were compared by a univariate analysis. Factors independently associated with a fever were established by a multivariate analysis. Results The criteria for SIRS were fulfilled in a greater proportion of patients in Group A (79%) than in Group B (42%, p=0.001). There was no difference in the procalcitonin concentration between Groups A and B (0.15±0.17 ng/mL vs. 0.11±0.12 ng/mL, respectively; p=0.572). Serum procalcitonin concentrations lay within the normal range in all patients in whom it was measured, which showed that the fever was caused by endogenous mediators. On the multivariate analysis, there was a borderline significant relationship between a fever and the prothrombin time-International Normalized Ratio (p=0.065), likely reflecting the extrinsic pathway activity initiated by tissue factor. Conclusion Our findings suggest that a fever in AAD could be caused by SIRS, provoked by endogenous mediators that influence the extrinsic coagulation pathway without elevating the serum procalcitonin concentration.

Practice Guidelines for Primary Care of Acute Abdomen 2015

Since acute abdomen requires accurate diagnosis and treatment within a particular time limit to prevent mortality, the Japanese Society for Abdominal Emergency Medicine, in collaboration with four other medical societies, launched the Practice Guidelines for Primary Care of Acute Abdomen that were the first English guidelines in the world for the management of acute abdomen. Here we provide the highlights of these guidelines (all clinical questions and recommendations were shown in supplementary information). A systematic and comprehensive evaluation of the evidence for epidemiology, diagnosis, differential diagnosis, and primary treatment for acute abdomen was performed to develop the Practice Guidelines for Primary Care of Acute Abdomen 2015. Because many types of pathophysiological events underlie acute abdomen, these guidelines cover the primary care of adult patients with nontraumatic acute abdomen. A total of 108 questions based on nine subject areas were used to compile 113 recommendations. The subject areas included definition, epidemiology, history taking, physical examination, laboratory test, imaging studies, differential diagnosis, initial treatment, and education. Japanese medical circumstances were considered for grading the recommendations to assure useful information. The two-step methods for the initial management of acute abdomen were proposed. Early use of transfusion and analgesia, particularly intravenous acetaminophen, were recommended. The Practice Guidelines for Primary Care of Acute Abdomen 2015 have been prepared as the first evidence-based guidelines for the management of acute abdomen. We hope that these guidelines contribute to clinical practice and improve the primary care and prognosis of patients with acute abdomen.

The development and application of a molecular community profiling strategy to identify polymicrobial bacterial DNA in the whole blood of septic patients

Background

The application of molecular based diagnostics in sepsis has had limited success to date. Molecular community profiling methods have indicated that polymicrobial infections are more common than suggested by standard clinical culture. A molecular profiling approach was developed to investigate the propensity for polymicrobial infections in patients predicted to have bacterial sepsis.

Results

Disruption of blood cells with saponin and hypotonic shock enabled the recovery of microbial cells with no significant changes in microbial growth when compared to CFU/ml values immediately prior to the addition of saponin. DNA extraction included a cell-wall digestion step with both lysozyme and mutanolysin, which increased the recovery of terminal restriction fragments by 2.4 fold from diverse organisms. Efficiencies of recovery and limits of detection using Illumina sequencing of the 16S rRNA V3 region were determined for both viable cells and DNA using mock bacterial communities inoculated into whole blood. Bacteria from pre-defined communities could be recovered following lysis and removal of host cells with > 97 % recovery of total DNA present. Applying the molecular profiling methodology to three septic patients in the intensive care unit revealed microbial DNA from blood had consistent alignment with cultured organisms from the primary infection site providing evidence for a bloodstream infection in the absence of a clinical lab positive blood culture result in two of the three cases. In addition, the molecular profiling indicated greater diversity was present in the primary infection sample when compared to clinical diagnostic culture.

Conclusions

A method for analyzing bacterial DNA from whole blood was developed in order to characterize the bacterial DNA profile of sepsis infections. Preliminary results indicated that sepsis infections were polymicrobial in nature with the bacterial DNA recovered suggesting a more complex etiology when compared to blood culture data.

Role of cardiac- and myeloid-MyD88 signaling in endotoxin shock: a study with tissue-specific deletion models

BACKGROUND

Myeloid differentiation factor 88 (MyD88) is an adaptor molecule critical for host innate immunity. Studies have shown that signaling via MyD88 contributes to cytokine storm, cardiac dysfunction, and high mortality during endotoxin shock.However, the specific contribution of MyD88 signaling of immune and cardiac origins to endotoxin shock remains unknown.

METHODS

Tissue-specific MyD88 deletion models: Cre-recombinase transgenic mice with α-myosin heavy chain (α-MHC) or lysozyme M promoters were cross-bred with MyD88-loxP (MyD88fl/fl) mice, respectively, to generate cardiomyocyte- (α-MHCMyD88−/−) or myeloid-specific (Lyz-MyD88−/−) MyD88 deletion models and their respective MyD88fl/fl littermates. Endotoxin shock model: Mice were subjected to 15 mg/kg lipopolysaccharide (intraperitoneal injection). Cardiac function was measured by echocardiography and cytokines by multiplex assay and quantitative reverse transcription-polymerase chain reaction.

RESULTS

α-MHC-MyD88−/− mice had 61 and 87% reduction in MyD88 gene and protein expression in cardiomyocytes,respectively, whereas Lyz-MyD88−/− had 73 and 67% decrease, respectively, in macrophages (n=3 per group). After lipopolysaccharide treatment, the two groups of MyD88fl/fl littermates had 46% (n=10) and 60% (n=15) of mortality, respectively.Both α-MHC-MyD88−/− and Lyz-MyD88−/− mice had markedly improved survival. Compared with the MyD88fl/fl littermates, Lyz-MyD88−/− mice had warmer body temperature, attenuated systemic and cardiac inflammatory cytokine production,and significantly improved cardiac function, whereas α-MHC-MyD88−/− mice had decreased myocardial inducible nitricoxide synthase induction and modestly preserved cardiac function.

CONCLUSIONS

Both cardiomyocyte- and myeloid-MyD88 signaling play a role in cardiac dysfunction and mortality during endotoxin shock. Myeloid-MyD88 signaling plays a predominant role in systemic and cardiac inflammation after endotoxin challenge.

Trends in bacterial wound isolates and antimicrobial susceptibility in a pediatric burn hospital

The purpose of this retrospective study was to collate data dealing with organisms cultured from the burn patients and evaluate trends in antimicrobial susceptibility. All cultures collected from each acute admission patient between 2004 and 2011 in the 30-bed pediatric burn hospital were evaluated for their annual frequency and antimicrobial susceptibility. Duplicate cultures were excluded. Staphylococcus aureus was isolated most frequently (25% of total isolates; range, 69-408 isolates/yr), followed by Pseudomonas aeruginosa (13%; range, 40-202 isolates/yr), coagulase-negative staphylococci (9%; range, 2-188 isolates/yr), Enterobacter cloacae (8%; range, 22-128 isolates/yr), and Escherichia coli (6%; range, 19-91 isolates/yr). This rank order remained relatively consistent during the period of study. The emergence of methicillin-resistant S. aureus increased from 20% in 2004 to about 45% in 2009 to 2011. Susceptibility to vancomycin was still 100%. In comparing periods 2004 to 2007 and 2008 to 2011, P. aeruginosa showed increased susceptibility to cefepime (from 76% to 84%) and the aminoglycosides (from 68% to 81%), whereas susceptibility to piperacillin-tazobactam remained high (from 91% to 93%). E. cloacae demonstrated 90 to 100% susceptibility to aminoglycosides, cefepime, and imipenem. E. coli showed an increased rate of resistance to ceftazidime but was still susceptible to imipenem and amikacin. S. aureus and P. aeruginosa continue to be the most prevalent organisms cultured from our pediatric burn population. Almost half of the staphylococcal isolates were methicillin-resistant S. aureus. Despite widespread use of piperacillin-tazobactam, P. aeruginosa susceptibility remained high. Several classes of antimicrobials continued to demonstrate good to excellent activity against the majority of organisms cultured from the burn patients.

Obesity-induced hyperleptinemia improves survival and immune response in a murine model of sepsis

BACKGROUND

Obesity is a growing health problem and associated with immune dysfunction. Sepsis is defined as systemic inflammatory response syndrome that occurs during infection. Excessive inflammation combined with immune dysfunction can lead to multiorgan damage and death.

METHODS

The authors investigated the influence of a class 1 obesity (body mass index between 30 and 34.9) on immune function and outcome in sepsis and the role of leptin on the immune response. The authors used a long-term high-fat-diet feeding model (12 weeks) on C57Bl/6 mice (n = 100) and controls on standard diet (n = 140) followed by a polymicrobial sepsis induced by cecal ligation and puncture.

RESULTS

The authors show that class 1 obesity is connected to significant higher serum leptin levels (data are mean ± SEM) (5.7 ± 1.2 vs. 2.7 ± 0.2 ng/ml; n = 5; P = 0.033) and improved innate immune response followed by significant better survival rate in sepsis (71.4%, n = 10 vs. 10%, n = 14; P < 0.0001). Additional sepsis-induced increases in leptin levels stabilize body temperature and are associated with a controlled immune response in a time-dependent and protective manner. Furthermore, leptin treatment of normal-weight septic mice with relative hypoleptinemia (n = 35) also significantly stabilizes body temperature, improves cellular immune response, and reduces proinflammatory cytokine response resulting in improved survival (30%; n = 10).

CONCLUSIONS

Relative hyperleptinemia of class 1 obesity or induced by treatment is protective in sepsis. Leptin seems to play a regulatory role in the immune system in sepsis, and treatment of relative hypoleptinemia could offer a new way of an individual sepsis therapy.

Independent influence of negative blood cultures and bloodstream infections on in-hospital mortality

Background

The independent influence of blood culture testing and bloodstream infection (BSI) on hospital mortality is unclear.

Methods

We included all adults treated in non-psychiatric services at our hospital between 2004 and 2011. We identified all blood cultures and their results to determine the independent association of blood culture testing and BSI on death in hospital using proportional hazards modeling that adjusted for important covariates.

Results

Of 297 070 hospitalizations, 48 423 had negative blood cultures and 5274 had BSI. 12 529 (4.2%) died in hospital. Compared to those without blood cultures, culture-negative patients and those with BSI were sicker. Culture-negative patients had a significantly increased risk of death in hospital (adjusted hazard ratio [HR] ranging between 3.1 and 4.4 depending on admission urgency, extent of comorbidities, and whether the blood culture was taken in the intensive care unit). Patients with BSI had a significantly increased risk of death (adj-HR ranging between 3.8 and 24.3] that was significantly higher when BSI was: diagnosed within the first hospital day; polymicrobial; in patients who were exposed to immunosuppressants or were neutropenic; or due to Clostridial and Candidal organisms. Death risk in culture negative and bloodstream infection patients decreased significantly with time.

Conclusions

Risk of death in hospital is independently increased both in patients with negative blood cultures and further in those with bloodstream infection. Death risk associated with bloodstream infections varied by the patient’s immune status and the causative microorganism.

Association of body temperature and antipyretic treatments with mortality of critically ill patients with and without sepsis: multi-centered prospective observational study

Introduction

Fever is frequently observed in critically ill patients. An independent association of fever with increased mortality has been observed in non-neurological critically ill patients with mixed febrile etiology. The association of fever and antipyretics with mortality, however, may be different between infective and non-infective illness.

Methods

We designed a prospective observational study to investigate the independent association of fever and the use of antipyretic treatments with mortality in critically ill patients with and without sepsis. We included 1,425 consecutive adult critically ill patients (without neurological injury) requiring > 48 hours intensive care admitted in 25 ICUs. We recorded four-hourly body temperature and all antipyretic treatments until ICU discharge or 28 days after ICU admission, whichever occurred first. For septic and non-septic patients, we separately assessed the association of maximum body temperature during ICU stay (MAX_ICU) and the use of antipyretic treatments with 28-day mortality.

Results

We recorded body temperature 63,441 times. Antipyretic treatment was given 4,863 times to 737 patients (51.7%). We found that treatment with non-steroidal anti-inflammatory drugs (NSAIDs) or acetaminophen independently increased 28-day mortality for septic patients (adjusted odds ratio: NSAIDs: 2.61, P = 0.028, acetaminophen: 2.05, P = 0.01), but not for non-septic patients (adjusted odds ratio: NSAIDs: 0.22, P = 0.15, acetaminophen: 0.58, P = 0.63). Application of physical cooling did not associate with mortality in either group. Relative to the reference range (MAX_ICU 36.5°C to 37.4°C), MAX_ICU ≥ 39.5°C increased risk of 28-day mortality in septic patients (adjusted odds ratio 8.14, P = 0.01), but not in non-septic patients (adjusted odds ratio 0.47, P = 0.11).

Conclusions

In non-septic patients, high fever (≥ 39.5°C) independently associated with mortality, without association of administration of NSAIDs or acetaminophen with mortality. In contrast, in septic patients, administration of NSAIDs or acetaminophen independently associated with 28-day mortality, without association of fever with mortality. These findings suggest that fever and antipyretics may have different biological or clinical or both implications for patients with and without sepsis.

Trial registration

ClinicalTrials.gov: NCT00940654

Severe hypothermia increases the risk for intensive care unit-acquired infection

BACKGROUND

Although hypothermia is widely accepted as a risk factor for subsequent infection in surgical patients, it has not been well defined in medical patients. We sought to assess the risk of acquiring intensive care unit (ICU)--acquired infection after hypothermia among medical ICU patients.

METHODS

Adults (≥18 years) admitted to French ICUs for at least 2 days between April 2000 and November 2010 were included. Surgical patients were excluded. Patient were classified as having had mild hypothermia (35.0°C-35.9°C), moderate hypothermia (32°C-34.9°C), or severe hypothermia (<32°C), and were followed for the development of pneumonia or bloodstream infection until ICU discharge.

RESULTS

A total of 6237 patients were included. Within the first day of admission, 648 (10%) patients had mild hypothermia, 288 (5%) patients had moderate hypothermia, and 45 (1%) patients had severe hypothermia. Among the 5256 patients who did not have any hypothermia at day 1, subsequent hypothermia developed in 868 (17%), of which 673 (13%), 176 (3%), and 19 (<1%) patients had lowest temperatures of 35.0°C-35.9°C, 32.0°C-34.9°C, and <32°C, respectively. During the course of ICU admission, 320 (5%) patients developed ICU-acquired bloodstream infection and 724 (12%) patients developed ICU-acquired pneumonia. After controlling for confounding variables in multivariable analyses, severe hypothermia was found to increase the risk for subsequent ICU-acquired infection, particularly in patients who did not present with severe sepsis or septic shock.

CONCLUSIONS

The presence of severe hypothermia is a risk factor for development of ICU-acquired infection in medical patients.

Fever in non-neurological critically ill patients: a systematic review of observational studies

PURPOSE

There is no recommendation on how increased body temperature should be treated in non-neurological critically ill patients. To understand the epidemiology of fever and its association with mortality, we conducted a systematic review of the literature to search for data related to the association between fever and mortality.

MATERIALS AND METHODS

We searched MEDLINE and PUBMED related articles and reference lists from January 1978 to July 2011 to select observational studies for assessment of the association of fever with mortality in non-neurological critically ill patients.

RESULTS

We reviewed 1464 articles and found 9 relevant articles. We found that (1) there is no uniform definition of fever, (2) fever (37.5°C to >39.0°C) was not significantly associated with mortality (odds ratio, 1.22; P = .52), and (3) high fever (39.3°C to 39.5°C) was significantly associated with mortality (odds ratio, 2.95; P = .03). We also found that there has been no multicenter prospective observational study including important confounding factors, such as the use of antipyretic treatments, steroids, and extracorporeal circuits.

CONCLUSIONS

The limited evidence available suggests that the recommended definition of fever (38.3°C) might be too low to predict increased mortality. Because fever is common in the intensive care unit, there is an urgent need for more studies in this field.

Mediators of systemic inflammatory response syndrome and the role of recombinant activated protein C in sepsis syndrome

The systemic inflammatory response syndrome, the host's response to infection involves a series of cascading events that mobilize a series of mediators involving the immune system, complement, and the coagulation cascade. Although the initial focus of mediators is to limit infection, this cascade may run amok and cause the development of hypotension, vascular instability, and disseminated intravascular coagulation, leading to morbidity and mortality in the host. Several therapeutic trials have focused on the modulation of these mediators, but use of recombinant human activated protein C in patients with severe sepsis is the only one that has shown a benefit in clinical trials.

Systematic review and meta-analysis of the efficacy of appropriate empiric antibiotic therapy for sepsis

Quantifying the benefit of early antibiotic treatment is crucial for decision making and can be assessed only in observational studies. We performed a systematic review of prospective studies reporting the effect of appropriate empirical antibiotic treatment on all-cause mortality among adult inpatients with sepsis. Two reviewers independently extracted data. Risk of bias was assessed using the Newcastle-Ottawa score. We calculated unadjusted odds ratios (ORs) with 95% confidence intervals for each study and extracted adjusted ORs, with variance, methods, and covariates being used for adjustment. ORs were pooled using random-effects meta-analysis. We examined the effects of methodological and clinical confounders on results through subgroup analysis or mixed-effect meta-regression. Seventy studies were included, of which 48 provided an adjusted OR for inappropriate empirical antibiotic treatment. Inappropriate empirical antibiotic treatment was associated with significantly higher mortality in the unadjusted and adjusted comparisons, with considerable heterogeneity occurring in both analyses (I(2) > 70%). Study design, time of mortality assessment, the reporting methods of the multivariable models, and the covariates used for adjustment were significantly associated with effect size. Septic shock was the only clinical variable significantly affecting results (it was associated with higher ORs). Studies adjusting for background conditions and sepsis severity reported a pooled adjusted OR of 1.60 (95% confidence interval = 1.37 to 1.86; 26 studies; number needed to treat to prevent one fatal outcome, 10 patients [95% confidence interval = 8 to 15]; I(2) = 46.3%) given 34% mortality with inappropriate empirical treatment. Appropriate empirical antibiotic treatment is associated with a significant reduction in all-cause mortality. However, the methods used in the observational studies significantly affect the effect size reported. Methods of observational studies assessing the effects of antibiotic treatment should be improved and standardized.

Chronic liver disease impairs bacterial clearance in a human model of induced bacteremia

Sepsis often causes impaired hepatic function. Patients with liver disease have an increased risk of bacteremia. This is thought to be secondary to impaired reticuloendothelial system function. However, this has not been demonstrated clinically. Since transient bacteremia occurs following toothbrushing, we hypothesized that subjects with cirrhosis would have impaired bacterial clearance following toothbrushing compared with subjects with pulmonary disease and healthy controls. After baseline blood was drawn, the subjects underwent a dental examination to determine plaque index and gingival index. Following toothbrushing, blood was drawn at 30 seconds, 5 minutes, and 15 minutes. Bacteremia was measured using quantitative real-time PCR with primers that amplify all known bacteria. We found greater than 75% incidence of bacteremia following toothbrushing. While control and pulmonary subjects were able to clear this bacteremia, subjects with cirrhosis had prolonged bacteremia. Baseline and peak bacterial load correlated with plaque index, suggesting that dental hygiene predicts the degree of bacteremia. However, only the severity of cirrhosis was predictive of bacterial clearance at 15 minutes, suggesting that liver function is important in clearing bacteremia. In this study, we demonstrate clinically that cirrhosis results in impaired bacterial clearance. This suggests that cirrhotic patients may be more susceptible to sepsis because of ineffective bacterial clearance.

CNS leptin action modulates immune response and survival in sepsis

Sepsis describes a complex clinical syndrome that results from an infection, setting off a cascade of systemic inflammatory responses that can lead to multiple organ failure and death. Leptin is a 16 kDa adipokine that, among its multiple known effects, is involved in regulating immune function. Here we demonstrate that leptin deficiency in ob/ob mice leads to higher mortality and more severe organ damage in a standard model of sepsis in mice [cecal ligation and puncture (CLP)]. Moreover, systemic leptin replacement improved the immune response to CLP. Based on the molecular mechanisms of leptin regulation of energy metabolism and reproductive function, we hypothesized that leptin acts in the CNS to efficiently coordinate peripheral immune defense in sepsis. We now report that leptin signaling in the brain increases survival during sepsis in leptin-deficient as well as in wild-type mice and that endogenous CNS leptin action is required for an adequate systemic immune response. These findings reveal the existence of a relevant neuroendocrine control of systemic immune defense and suggest a possible therapeutic potential for leptin analogs in infectious disease.

Risk factors for death after sepsis in patients immunosuppressed before the onset of sepsis

Few studies have focused on sepsis in patients with pre-existing immunosuppression. Since the numbers and the incidence of sepsis are increasing, sepsis in immunosuppressed patients will increase in importance. We studied the epidemiology of sepsis and risk factors for 28-d mortality in patients immunosuppressed prior to the onset of sepsis using data from the Academic Medical Center Consortium's (AMCC) prospective observational cohort study of sepsis. We compared characteristics of immunosuppressed (n =412) and immunocompetent (n =754) patients. Immunosuppressed patients were younger and more likely to have underlying liver or lung disease, and nosocomial infection or bloodstream infection of unknown source when presenting with sepsis. They were also more likely to die within 28 d compared to immunocompetent patients (adjusted relative risk 1.62, 95% CI 1.38 - 1.91). Septic shock, hypothermia, cancer and invasive fungal infections were associated with increased mortality in immunosuppressed patients. Black race and the presence of rigors were independent predictors of survival in immunosuppressed patients. We conclude that sepsis among patients immunosuppressed prior to the onset of sepsis was associated with higher mortality than in immunocompetent patients. As the numbers of immunosuppressed patients continue to grow, more studies on the epidemiology of sepsis in this group will become increasingly important.

Prognostic factors of mortality in patients with community-acquired bloodstream infection with severe sepsis and septic shock

PURPOSE

The purpose of the study was to determine the independent risk factors on mortality in patients with community-acquired severe sepsis and septic shock.

METHODS

A single-site prospective cohort study was carried out in a medical-surgical intensive care unit in an academic tertiary care center. One hundred twelve patients with community-acquired bloodstream infection with severe sepsis and septic shock were identified. Clinical, microbiologic, and laboratory parameters were compared between hospital survivors and hospital deaths.

RESULTS

One-hundred twelve patients were included. The global mortality rate was 41.9%, 44.5% in septic shock and 34.4% in severe sepsis. One or more comorbidities were present in 66% of patients. The most commonly identified bloodstream pathogens were Escherichia coli (25%) and Staphylococcus aureus (21.4%). The proportion of patients receiving inadequate antimicrobial treatment was 8.9%. By univariate analysis, age, Acute Physiology and Chronic Health Evaluation II score, at least 3 organ dysfunctions, and albumin, but neither microbiologic characteristics nor site of infection, differed significantly between survivors and nonsurvivors. Acute Physiology and Chronic Health Evaluation II (odds ratio, 1.13; 95% confidence interval, 1.06-1.21) and albumin (odds ratio, 0.34; 95% confidence interval, 0.15-0.76) were independent risk factors associated with global mortality in logistic regression analysis.

CONCLUSION

In addition to the severity of illness, hypoalbuminemia was identified as the most important prognostic factor in community-acquired bloodstream infection with severe sepsis and septic shock.

Prediction of severe sepsis using SVM model

Sepsis is an infectious condition that results in damage to organs. This paper proposes a severe sepsis model based on Support Vector Machine (SVM) for predicting whether a septic patient will become severe sepsis. We chose several clinical physiology of sepsis for identifying the features used for SVM. Based on the model, a medical decision support system is proposed for clinical diagnosis. The results show that the prognosis of a septic patient can be more precisely predicted than ever. We conduct several experiments, whose results demonstrate that the proposed model provides high accuracy and high sensitivity and can be used as a reminding system to provide in-time treatment in ICU.

Using hierarchical dynamic Bayesian networks to investigate dynamics of organ failure in patients in the Intensive Care Unit

In intensive care medicine close monitoring of organ failure status is important for the prognosis of patients and for choices regarding ICU management. Major challenges in analyzing the multitude of data pertaining to the functioning of the organ systems over time are to extract meaningful clinical patterns and to provide predictions for the future course of diseases. With their explicit states and probabilistic state transitions, Markov models seem to fit this purpose well. In complex domains such as intensive care a choice is often made between a simple model that is estimated from the data, or a more complex model in which the parameters are provided by domain experts. Our primary aim is to combine these approaches and develop a set of complex Markov models based on clinical data. In this paper we describe the design choices underlying the models, which enable them to identify temporal patterns, predict outcomes, and test clinical hypotheses. Our models are characterized by the choice of the dynamic hierarchical Bayesian network structure and the use of logistic regression equations in estimating the transition probabilities. We demonstrate the induction, inference, evaluation, and use of these models in practice in a case-study of patients with severe sepsis admitted to four Dutch ICUs.

Mouse eosinophils possess potent antibacterial properties in vivo

Eosinophils are best known as the predominant cellular infiltrate associated with asthma and parasitic infections. Recently, numerous studies have documented the presence of Toll-like receptors (TLRs) on the surfaces of eosinophils, suggesting that these leukocytes may participate in the recognition and killing of viruses and bacteria. However, the significance of this role in the innate immune response to bacterial infection is largely unknown. Here we report a novel role for eosinophils as antibacterial defenders in the host response. Isolated mouse eosinophils possessed antipseudomonal properties in vitro. In vivo, interleukin-5 transgenic mice, which have profound eosinophilia, demonstrated improved clearance of Pseudomonas aeruginosa introduced into the peritoneal cavity. The findings of improved bacterial clearance following adoptive transfer of eosinophils, and impaired bacterial clearance in mice with a congenital eosinophil deficiency, established that this effect was eosinophil specific. The data presented also demonstrate that eosinophils mediate this antibacterial effect in part through the release of cationic secondary granule proteins. Specifically, isolated eosinophil granules had antibacterial properties in vitro, and administration of eosinophil granule extracts significantly improved bacterial clearance in vivo. These data suggest a potent yet underappreciated antibacterial role for eosinophils in vivo, specifically for eosinophil granules. Moreover, the data suggest that the administration of eosinophil-derived products may represent a viable adjuvant therapy for septic or bacteremic patients in the intensive care unit.

Predictors of mortality in beta-hemolytic streptococcal bacteremia: a population-based study

OBJECTIVES

Several factors associated with mortality in Lancefield group A beta-hemolytic streptococcal bacteremia have been described in population-based surveillance studies, whereas such reports on group B, C, and G streptococcal are scant.

METHODS

In this population-based study all 314 episodes of beta-hemolytic streptococcal bacteremia in adult patients in the Pirkanmaa area, Finland, during the 10-year period 1995-2004 were retrospectively reviewed.

RESULTS

The 30-day case-fatality rate was 13%, being highest in group C (22%); in group A it was 15%, in group B 7%, and in group G 15%. Confusion, unconsciousness and dyspnea as the first sign or symptom were associated with increased case-fatality, while fever seemed to be a protecting factor for death. Alcoholism and ultimately or rapidly fatal underlying disease were significantly associated with increased case-fatality. Among infections of the skin and soft-tissues, necrotizing fasciitis had the highest risk of death (38%), while patients with cellulitis had a case-fatality of 8%. A history of previous cellulitis seemed to protect against death (case-fatality of 3% as compared to 16% among those without such a history (p=0.014)).

CONCLUSION

A history of previous cellulitis seemed to be a protecting factor against death. Fever was also associated with a good prognosis.

The epidemiology of, and risk factors for, mortality from severe sepsis and septic shock in a tertiary-care university hospital setting

This study investigated the clinical characteristics of, and outcomes and risk factors for hospital mortality of 390 patients admitted with severe sepsis or septic shock in an intensive care unit (ICU). Prospectively collected data from patients collected between 1 July 2004 and 30 June 2006 were analysed. Overall hospital mortality was 49.7% and comorbidities were found in 40.3% of patients, the most common of which was haematological malignancy. The respiratory tract was the most common site of infection (50%). Hospital-acquired infections accounted for 55.6% of patients with Gram-negative bacteria predominant (68%). Multivariate analysis showed that acute respiratory distress syndrome, pulmonary artery catheter placement, comorbidities, hospital-acquired infection, APACHE II score and maximum LOD score, were independent risk factors for hospital mortality. In conclusion, severe sepsis and septic shock are common causes of ICU admission. Patients with risk factors for increased mortality should be carefully monitored and aggressive treatment administered.

The clinical research enterprise in critical care: what's right, what's wrong, and what's ahead?

Intensivists have been remarkably successful in using randomized controlled trials to assess aspects of current practice. Unfortunately, this success has not been mirrored in trials of new pharmacotherapy, despite convincing pathophysiological rationales and encouraging preliminary studies. Misunderstandings of biological processes and flawed early clinical studies have led to the almost universal failure of fundamentally new treatments subjected to large phase III trials, despite their sound methodology. Compounding these problems is the tendency for new approaches to be either implemented widely on the basis of relatively poor studies or ignored despite strong supporting evidence. Having mastered the principles of evidence-based medicine in assessing existing therapy, intensivists have established a strong foundation. Critical care medicine must now embrace the challenge of translating a more solid understanding of basic disease mechanisms into widely implemented treatments.

Validation criteria for nucleic acid amplification techniques for bacterial infections

Nucleic acid techniques (NATs), such as species-specific and universal polymerase chain reactions (PCRs), are finding ever wider use in the diagnosis of bacterial infection. However, although universal PCR assays, in particular, approach a type of modern Petri dish, they have a number of limitations which restrict their applicability. The sensitivity of universal PCR is lower than that of many species-specific PCRs, and the contamination of samples and PCR reagents with irrelevant DNA from various sources remains a problem. Thus, NATs in general and universal PCR assays in particular require careful validation to be of value for the diagnosis of infection. Validation includes sampling, DNA extraction/isolation, template amplification and visualisation of the results. Furthermore, it implies the establishment of measures of asepsis, the inclusion of positive and negative controls, techniques to optimise the release of DNA from bacterial cells, adequate repetition of the amplification reaction, and routine testing of reagent negative and inhibition controls. Finally, it entails the comparison of results obtained by NATs with those obtained by conventional microbiological methods and matching with clinical evidence of infection. Validation of NATs in clinical diagnosis remains an ongoing challenge. Because of these limitations, NATs can only serve as adjunct tools for the diagnosis of infection in selected cases; they cannot replace conventional culturing techniques.

Impact of adverse events on outcomes in intensive care unit patients

OBJECTIVE

To examine the association between predefined adverse events (AE) (including nosocomial infections) and intensive care unit (ICU) mortality, controlling for multiple adverse events in the same patient and confounding variables.

DESIGN

Prospective observational cohort study of the French OUTCOMEREA multicenter database.

SETTING

Twelve medical or surgical ICUs.

PATIENTS

Unselected patients hospitalized for > or = 48 hrs enrolled between 1997 and 2003.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 3,611 patients included, 1415 (39.2%) experienced one or more AEs and 821 (22.7%) had two or more AEs. Mean number of AEs per patient was 2.8 (range, 1-26). Six AEs were associated with death: primary or catheter-related bloodstream infection (BSI) (odds ratio [OR], 2.92; 95% confidence interval [CI], 1.6-5.32), BSI from other sources (OR, 5.7; 95% CI, 2.66-12.05), nonbacteremic pneumonia (OR, 1.69; 95% CI, 1.17-2.44), deep and organ/space surgical site infection without BSI (OR, 3; 95% CI, 1.3-6.8), pneumothorax (OR, 3.1; 95% CI, 1.5-6.3), and gastrointestinal bleeding (OR, 2.6; 95% CI, 1.4-4.9). The results were not changed when the analysis was confined to patients with mechanical ventilation on day 1, intermediate severity of illness (Simplified Acute Physiology Score II between 35 and 55), no treatment-limitation decisions, or no cardiac arrest in the ICU.

CONCLUSIONS

AEs were common and often occurred in combination in individual patients. Several AEs independently contributed to death. Creating a safe ICU environment is a challenging task that deserves careful attention from ICU physicians.

Who needs a blood culture? A prospectively derived and validated prediction rule

The study objective was to derive and validate a clinical decision rule for obtaining blood cultures in Emergency Department (ED) patients with suspected infection. This was a prospective, observational cohort study of consecutive adult ED patients with blood cultures obtained. The study ran from February 1, 2000 through February 1, 2001. Patients were randomly assigned to derivation (2/3) or validation (1/3) sets. The outcome was "true bacteremia." Features of the history, co-morbid illness, physical examination, and laboratory testing were used to create a clinical decision rule. Among 3901 patients, 3730 (96%) were enrolled with 305 (8.2%) episodes of true bacteremia. A decision rule was created with "major criteria" defined as: temperature > 39.5 degrees C (103.0 degrees F), indwelling vascular catheter, or clinical suspicion of endocarditis. "Minor criteria" were: temperature 38.3-39.4 degrees C (101-102.9 degrees F), age > 65 years, chills, vomiting, hypotension (systolic blood pressure < 90 mm Hg), neutrophil% > 80, white blood cell count > 18 k, bands > 5%, platelets < 150 k, and creatinine > 2.0. A blood culture is indicated by the rule if at least one major criterion or two minor criteria are present. Otherwise, patients are classified as "low risk" and cultures may be omitted. Only 4 (0.6%) low-risk patients in the derivation set and 3 (0.9%) low-risk patients in the validation set had positive cultures. The sensitivity was 98% (95% confidence interval [CI] 96-100%) (derivation) and 97% (95% CI 94-100%) (validation). We developed and validated a promising clinical decision rule for predicting bacteremia in patients with suspected infection.

Insulin-like growth factor-1 improves survival in sepsis via enhanced hepatic bacterial clearance

RATIONALE

Both insulin-like growth factor (IGF)-1 and bacterial clearance by Kupffer cells are significantly reduced in severe sepsis. Kupffer cell apoptosis is triggered by tumor necrosis factor (TNF)-alpha and activation of the PI-3 kinase pathway prevents TNF-induced Kupffer cell death.

OBJECTIVES

We evaluated if the marked decline in IGF-1 is related to bacterial clearance in sepsis.

METHODS

Sepsis was induced in C57BL/6 mice by intratracheal inoculation with Pseudomonas aeruginosa (strain PA103). Some mice received IGF-1 24 mg/kg either before infection or 12 hours after infection. In vitro studies were performed using the clonal Kupffer cell line KC13-2.

MEASUREMENTS AND MAIN RESULTS

Sepsis resulted in decreased levels of IGF-1. In vitro studies with KC13-2 cells demonstrated that IGF-1 protected Kupffer cells against TNF-alpha-induced apoptosis by activating the PI-3 kinase pathway and stabilizing the inhibitor of apoptosis protein, XIAP. In the animal model, pretreatment with IGF-1 decreased hepatic TNF-alpha and IL-6, improved hepatic bacterial clearance as demonstrated by real-time polymerase chain reaction with primers specific for P. aeruginosa, and improved survival in severe sepsis. Moreover, we rescued mice from severe sepsis by IGF-1 treatment 12 hours after infection.

CONCLUSIONS

These studies show that the decline in IGF-1 levels in sepsis is related to bacterial clearance and that replacement of IGF-1 in a murine model of sepsis improves overall survival.

Systematic review of randomized clinical trials on the use of hydroxyethyl starch for fluid management in sepsis

Background

Patients with sepsis typically require large resuscitation volumes, but the optimal type of fluid remains unclear. The aim of this systematic review was to evaluate current evidence on the effectiveness and safety of hydroxyethyl starch for fluid management in sepsis.

Methods

Computer searches of MEDLINE, EMBASE and the Cochrane Library were performed using search terms that included hydroxyethyl starch; hetastarch; shock, septic; sepsis; randomized controlled trials; and random allocation. Additional methods were examination of reference lists and hand searching. Randomized clinical trials comparing hydroxyethyl starch with other fluids in patients with sepsis were selected. Data were extracted on numbers of patients randomized, specific indication, fluid regimen, follow-up, endpoints, hydroxyethyl starch volume infused and duration of administration, and major study findings.

Results

Twelve randomized trials involving a total of 1062 patients were included. Ten trials (83%) were acute studies with observation periods of 5 days or less, most frequently assessing cardiorespiratory and hemodynamic variables. Two trials were designed as outcome studies with follow-up for 34 and 90 days, respectively. Hydroxyethyl starch increased the incidence of acute renal failure compared both with gelatin (odds ratio, 2.57; 95% confidence interval, 1.13–5.83) and crystalloid (odds ratio, 1.81; 95% confidence interval, 1.22–2.71). In the largest and most recent trial a trend was observed toward increased overall mortality among hydroxyethyl starch recipients (odds ratio, 1.35; 95% confidence interval, 0.94–1.95), and mortality was higher (p < 0.001) in patients receiving > 22 mL·kg^-1 hydroxyethyl starch per day than lower doses.

Conclusion

Hydroxyethyl starch increases the risk of acute renal failure among patients with sepsis and may also reduce the probability of survival. While the evidence reviewed cannot necessarily be applied to other clinical indications, hydroxyethyl starch should be avoided in sepsis.

Application of the sequential organ failure assessment (SOFA) score to bacteremic ICU patients

BACKGROUND

Patients admitted to intensive care units (ICUs) are at a high risk of acquiring blood stream infections. We examined whether SOFA score on ICU admission and on the day of bacteremia can predict the occurrence of bacteremia and the outcome of bacteremic ICU patients.

PATIENTS AND METHODS

All patients admitted to a multidisciplinary ICU for more than 48 h from January 1, 2002 to December 31, 2004, were prospectively studied. Demographic, clinical and laboratory data were recorded on admission for all patients and additionally, on the day of the first bacteremic episode for those patients who developed bacteremia. Accordingly, APACHE II and SOFA scores were calculated on the same day.

RESULTS

A total of 185 patients developed one or more episodes of bacteremia, giving an incidence of 9.6 per 1,000 ICU days. The ICU mortality rate was 43.9% for bacteremic and 25.8% for the remaining patients (p < 0.001). Admission SOFA score was independently associated with the occurrence of bacteremia (OR = 1.20, 95% CI: 1.11-1.26, p < 0.001). Among bacteremic patients, SOFA score on the day of bacteremia was the only independent prognostic factor for outcome (OR = 1.44, 95% CI: 1.21-1.71, p < 0.001). When all patients were included in the multivariate analysis, admission SOFA (OR = 1.3, CI: 1.16-1.38, p < 0.001), APACHE II (OR = 1.1, CI: 1.02-1.11, p = 0.003) score and the presence of bacteremia (OR = 1.8, CI: 1.1-2.9, p = 0.023) were independently associated with the outcome.

CONCLUSION

Admission SOFA score is independently associated with the occurrence of ICU-acquired bacteremia, whereas it is not sufficient to predict the outcome of patients who subsequently will develop this complication. However, SOFA score on the first day of bacteremia is an independent prognostic factor for outcome in these patients.

Device-associated hospital-acquired infection rates in Turkish intensive care units. Findings of the International Nosocomial Infection Control Consortium (INICC)

We conducted a prospective study of targeted surveillance of healthcare-associated infections (HAIs) in 13 intensive care units (ICUs) from 12 Turkish hospitals, all members of the International Nosocomial Infection Control Consortium (INICC). The definitions of the US Centers for Disease Control and Prevention National Nosocomial Infections Surveillance System (NNISS) were applied. During the three-year study, 3288 patients for accumulated duration of 37 631 days acquired 1277 device-associated infections (DAI), an overall rate of 38.3% or 33.9 DAIs per 1000 ICU-days. Ventilator-associated pneumonia (VAP) (47.4% of all DAI, 26.5 cases per 1000 ventilator-days) gave the highest risk, followed by central venous catheter (CVC)-related bloodstream infections (30.4% of all DAI, 17.6 cases per 1000 catheter-days) and catheter-associated urinary tract infections (22.1% of all DAI, 8.3 cases per 1000 catheter-days). Overall 89.2% of all Staphylococcus aureus infections were caused by methicillin-resistant strains, 48.2% of the Enterobacteriaceae isolates were resistant to ceftriaxone, 52.0% to ceftazidime, and 33.2% to piperacilin-tazobactam; 51.1% of Pseudomonas aeruginosa isolates were resistant to fluoroquinolones, 50.7% to ceftazidime, 38.7% to imipenem, and 30.0% to piperacilin-tazobactam; 1.9% of Enterococcus sp. isolates were resistant to vancomycin. This is the first multi-centre study showing DAI in Turkish ICUs. DAI rates in the ICUs of Turkey are higher than reports from industrialized countries.

Benefits of a synbiotic formula (Synbiotic 2000Forte) in critically Ill trauma patients: early results of a randomized controlled trial

BACKGROUND

Since probiotics are considered to exert beneficial health effects by enhancing the host's immune response, we investigated the benefits of a synbiotics treatment on the rate of infections, systemic inflammatory response syndrome (SIRS), severe sepsis, and mortality in critically ill, mechanically ventilated, multiple trauma patients. Length of stay in the intensive care unit (ICU) and number of days under mechanical ventilation were also evaluated.

METHOD

Sixty-five patients were randomized to receive once daily for 15 days a synbiotic formula (Synbiotic 2000Forte, Medipharm, Sweden) or maltodextrin as placebo. The synbiotic preparation consisted of a combination of four probiotics (10(11) CFU each): Pediococcus pentosaceus 5-33:3, Leuconostoc mesenteroides 32-77:1, L. paracasei ssp. paracasei 19; and L. plantarum 2,362; and inulin, oat bran, pectin, and resistant starch as prebiotics. Infections, septic complications, mortality, days under ventilatory support, and days of stay in ICU were recorded.

RESULTS

Synbiotic-treated patients exhibited a significantly reduced rate of infections (P = 0.01), SIRS, severe sepsis (P = 0.02), and mortality. Days of stay in the ICU (P = 0.01) and days under mechanical ventilation were also significantly reduced in relation to placebo (P = 0.001).

CONCLUSION

The administration of this synbiotic formula in critically ill, mechanically ventilated, multiple trauma patients seems to exert beneficial effects in respect to infection and sepsis rates and to improve the patient's response, thus reducing the duration of ventilatory support and intensive care treatment.

Usefulness of a Molecular Strategy for the Detection of Bacterial DNA in Patients with Severe Sepsis Undergoing Continuous Renal Replacement Therapy

INTRODUCTION

Sepsis is a major cause of morbidity and mortality in critically ill patients. Sepsis is associated with cell necrosis and apoptosis. Circulating plasma levels of DNA have been found in conditions associated with cell death, including sepsis, pregnancy, stroke, myocardial infarction and trauma. Plasma DNA can also derive from bacteria. We have recently implemented a method to detect bacterial DNA and, in the present study, we validated this technique comparing it to standard blood culture in terms of diagnostic efficacy.

METHODS

We examined a cohort of 9 critically ill patients with a diagnosis of severe sepsis and acute renal failure requiring continuous renal replacement therapy (CRRT). We analyzed bacterial DNA in blood, hemofilters, and ultrafiltrate (UF) by polymerase chain reaction amplification of 16S rRNA gene sequence analysis. Standard blood cultures were performed for all patients.

RESULTS

The blood cultures from 2 of the 9 (22%) patients were positive. However, bacterial DNA was identified in the blood of 6 patients (67%), including the 2 septic patients with positive blood cultures. In 9 (100%) patients bacterial DNA was found on the filter blood side, whereas in 7 (78%) subjects it was found in the dialysate compartment of the hemofilters. Bacterial DNA was never detected in the UF.

CONCLUSIONS

Using the 16S rRNA gene, the detection of bacterial DNA in blood and adsorbed within the filter could be a useful screening tool in clinically septic, blood culture-negative patients undergoing CRRT. However, the identification of the etiologic agent is not feasible with this technique because specific primers for the defined bacteria must be used to further identify the suspected pathogenic organisms.

Cost of intensive care unit-acquired bloodstream infections

Intensive care unit-acquired (ICU-acquired) bloodstream infections (BSI) are an important complication of critical illness. The objective of this study was to quantify the excess length of stay, mortality and cost attributable to ICU-acquired BSI. A matched cohort study was conducted in all adult ICUs in the Calgary Health Region between 1 May 2000 and 30 April 2003. One hundred and forty-four patients with ICU-acquired BSI were matched (1:1) to patients without ICU-acquired BSI. Patients with ICU-acquired BSI had a significantly increased median length of ICU stay {15.5 [interquartile range (IQR) 8-26] days vs 12 [IQR 7-18.5] days, P=0.003} and median costs of hospital care [85,137 dollars (IQR 45,740-131,412 dollars) vs 67,879 dollars (IQR 35,043-115,915 dollars, P=0.02) compared with patients without ICU-acquired BSI. The median excess length of ICU stay was two days and the median cost attributable to ICU-acquired BSI was 12,321 dollars per case. Sixty (42%) of the cases died compared with 37 (26%) of the controls [P=0.002, attributable mortality 16%, 95% confidence interval (CI) 5.9-26.0%]. Patients with ICU-acquired BSI were at increased risk for in-hospital death (odds ratio=2.64, 95%CI 1.40-5.29). Among survivor-matched pairs, the median excess lengths of ICU and hospital stay attributable to development of ICU-acquired BSI were two and 13.5 days, respectively, and the attributable cost due to ICU-acquired BSI was 25,155 dollars per case survivor. Critically ill patients who develop ICU-acquired BSI suffer excess morbidity and mortality, and incur significantly increased healthcare costs. These data support expenditures on infection prevention and control programmes and further research into reducing the impact of these infections.