Procalcitonin-guided algorithms of antibiotic therapy in the intensive care unit: A systematic review and meta-analysis of randomized controlled trials:

Effective Biomarkers for Diagnosis of Neonatal Sepsis

Infection in neonates continues to be a global problem with significant morbidity and mortality. The diagnosis of neonatal sepsis is complicated by nonspecific clinical symptomatology, a high-false negative rate, and a delay in obtaining blood culture results. An ideal biomarker needs to have a high degree of accuracy in recognizing the presence or absence of definite infection at an early stage, to guide the initiation and duration of antibiotic therapy. The diagnostic utility of the following biomarkers seems to be most practical in the early (interleukin [IL]-6, IL-8, tumor necrosis factor-alpha, neutrophil CD64), mid (procalcitonin) and late (C-reactive protein) phases of neonatal sepsis. Future research studies to assess reliability of these biomarkers should be (1) adequately powered for sample size and (2) use the gold-standard definition of blood-culture proven pathogen-specific sepsis. Significant advances in diagnostic accuracy of novel biomarkers to allow early, accurate, and cost-effective identification of pathogens responsible for neonatal sepsis is anticipated in the next 5 years.

Procalcitonin Elevation Suggests a Septic Source

Procalcitonin is used as a marker for sepsis but there is little known about the correlation of the procalcitonin elevation with the causative organism in sepsis. All patients aged 18 to 80 years who were admitted to the surgery service from June 2010 to May 2012 and who had a procalcitonin drawn were evaluated. Culture data were reviewed to determine the causative organism. Infections analyzed included pneumonia, urinary tract infection (UTI), bloodstream infection, and Clostridium difficile. Other parameters assessed included reason for admission, body mass index, pressor use, antibiotic duration, and disposition. Two hundred thirty-two patient records were reviewed. Patients without a known infection/source of sepsis had a mean procalcitonin of 3.95. Those with pneumonia had a procalcitonin of 20.59 ( P = 0.03). Those with a UTI had a mean procalcitonin of 66.84 ( P = 0.0005). Patients with a bloodstream infection had a mean procalcitonin of 33.30 ( P = 0.003). Those with C. difficile had a procalcitonin of 47.20 ( P = 0.004). When broken down by causative organisms, those with Gram-positive sepsis had a procalcitonin of 23.10 ( P = 0.02) compared with those with Gram-negative sepsis at 32.75 ( P = 0.02). Those with fungal infections had a procalcitonin of 42.90 ( P = 0.001). These data suggest that procalcitonin elevation can help guide treatment by indicating likely causative organism and infection type. These data may provide a good marker for initiation of antifungal therapy.

Antibiotic stewardship in the intensive care unit

The rapid emergence and dissemination of antimicrobial-resistant microorganisms in ICUs worldwide constitute a problem of crisis dimensions. The root causes of this problem are multifactorial, but the core issues are clear. The emergence of antibiotic resistance is highly correlated with selective pressure resulting from inappropriate use of these drugs. Appropriate antibiotic stewardship in ICUs includes not only rapid identification and optimal treatment of bacterial infections in these critically ill patients, based on pharmacokinetic-pharmacodynamic characteristics, but also improving our ability to avoid administering unnecessary broad-spectrum antibiotics, shortening the duration of their administration, and reducing the numbers of patients receiving undue antibiotic therapy. Either we will be able to implement such a policy or we and our patients will face an uncontrollable surge of very difficult-to-treat pathogens.

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.

Clinical usefulness of novel serum and imaging biomarkers in risk stratification of patients with stable angina

Inflammatory mediators appear to be the most intriguing yet confusing subject, regarding the management of patients with acute coronary syndromes (ACS). The current inflammatory concept of atherosclerotic coronary artery disease (CAD) led many investigators to concentrate on systemic markers of inflammation, as well as imaging techniques, which may be helpful in risk stratification and prognosis assessment for cardiovascular events. In this review, we try to depict many of the recently studied markers regarding stable angina (SA), their clinical usefulness, and possible future applications in the field.

Diagnostic potential of endotoxin scattering photometry for sepsis and septic shock

Endotoxin scattering photometry (ESP) is a novel Limulus amebocyte lysate (LAL) assay that uses a laser light-scattering particle-counting method. In the present study, we compared ESP, standard turbidimetric LAL assay, and procalcitonin assay for the evaluation of sepsis after emergency gastrointestinal surgery. A total of 174 samples were collected from 40 adult patients undergoing emergency gastrointestinal surgery and 10 patients with colorectal cancer undergoing elective surgery as nonseptic controls. Plasma endotoxin levels were measured with ESP and turbidimetric LAL assay, and plasma procalcitonin levels were assessed with a standard procalcitonin assay. Plasma endotoxin and procalcitonin levels increased corresponding to the degree of sepsis. Endotoxin scattering photometry significantly discriminated between patients with or without septic shock: sensitivity, 81.1%; specificity, 76.6%; positive predictive value, 48.4%; negative predictive value, 93.8%; and accuracy, 77.6%. The area under the receiver operating characteristic curve for septic shock with the ESP assay (endotoxin cutoff value, 23.8 pg/mL) was 0.8532 ± 0.0301 (95% confidence interval, 0.7841-0.9030; P < 0.0001). The predictive power of ESP was superior to that of turbidimetric assay (difference, 0.1965 ± 0.0588; 95% confidence interval, 0.0812-0.3117; P = 0.0008). There was no significant difference in predictive power between ESP and procalcitonin assay. Endotoxin scattering photometry also discriminated between patients with and without sepsis. Area under the receiver operating characteristic curve analysis showed that ESP had the best predictive power for diagnosing sepsis. In conclusion, compared with turbidimetric LAL assay, ESP more sensitively detected plasma endotoxin and significantly discriminated between sepsis and septic shock in patients undergoing gastrointestinal emergency surgery.

Evaluation of procalcitonin as a marker to predict antibiotic response in adult patients with acute appendicitis: a prospective observational study

BACKGROUND

The aim of the study was to investigate the value of serum procalcitonin (PCT) as a predictor of early antibiotic treatment response in patients with acute appendicitis. Procalcitonin is a biochemical marker that increases rapidly in cases of bacterial infection and sepsis; however, the benefit of PCT as a diagnostic tool in acute appendicitis has not been confirmed.

METHODS

Observations of PCT dynamics were conducted as part of a prospective clinical trial at Sahlgrenska University Hospital between May 2009 and February 2010 on adult patients with acute appendicitis treated with antibiotics as first-line therapy. Procalcitonin, C-reactive protein (CRP), and white blood cell count (WBC) were measured before administration of antibiotics and subsequently between 4-24 h following treatment.

RESULTS

Three hundred sixteen patients were included in the study. Almost 80% recovered on antibiotics without the need of surgery. Serum PCT concentrations before initiation of antibiotic therapy and during treatment did not differ significantly between antibiotic responders and non-responders (p<0.94). However, differences were observed for CRP (p<0.04) and WBC (p<0.001), with a trend for body temperature (p<0.06).

CONCLUSION

Procalcitonin has limited additional value, compared with standard laboratory tests as CRP, WBC, and body temperature to predict antibiotic treatment response in adult patients with acute appendicitis.

Clinical outcomes after utilizing surviving sepsis campaign in children with septic shock and prognostic value of initial plasma NT-proBNP

BACKGROUND AND OBJECTIVE

The surviving sepsis campaign treatment guideline (SSC) implementation is associated with improved outcome in adults with severe sepsis. The effect on outcome of pediatric sepsis is less clear.

PURPOSE

To determine the clinical outcomes of SSC implementation and to investigate the prognostic value of initial plasma NT-proBNP and procalcitonin in children.

MATERIALS AND METHODS

Infants and children (aged 1month/0-15 years with severe sepsis or septic shock) were prospectively enrolled and treated according to the guidelines. Initial blood drawn was saved for NT-pro-BNP, procalcitonin measurements and clinical data were also recorded.

RESULTS

A total of 47 subjects were recruited. Since the application of the SSC, our mortality rate had significantly decreased from 42-19% (P = 0.003) as compared to the data in the previous 3 years. Clinical factors that significantly increased the mortality rate were: Initial central venous oxygen saturation < 7 0% after fluid resuscitation [odds ratio (OR) = 23.3; 95% confidence interval (CI) 3.7-143; P = 0.001], and initial albumin level (≤ 3 g/dl, OR = 6.7; 95% CI 1.2-37.5, P = 0.03). There was asignificant difference between the initial NT-proBNP levels between survivors and non survivors, (6280.3 ± 9597 ng/L, P < 0.001), but not for procalcitonin (12.7 ± 24.8, 29.3 ± 46 μg/L, P = 0.1), respectively. An initial NT-proBNP level of more than 11,200 pg/ml predicted Pediatric Intensive Care Unit (PICU) mortality with a sensitivity of 85.7% and a specificity of 90%.

CONCLUSIONS

A modified SSC for severe sepsis and septic shock significantly reduced the mortality rate in our PICU. High initial NT-ProBNP level was associated with mortality.

Biomarkers of sepsis

Sepsis remains a leading cause of death in critically ill patients, despite efforts to improve patient outcome. Thus far, no magic drugs exist for severe sepsis and septic shock. Instead, early diagnosis and prompt initial management such as early goal-directed therapy are key to improve sepsis outcome. For early detection of sepsis, biological markers (biomarkers) can help clinicians to distinguish infection from host response to inflammation. Ideally, biomarkers can be used for risk stratification, diagnosis, monitoring of treatment responses, and outcome prediction. More than 170 biomarkers have been identified as useful for evaluating sepsis, including C-reactive protein, procalcitonin, various cytokines, and cell surface markers. Recently, studies have reported on the usefulness of biomarker-guided antibiotic stewardships. However, the other side of these numerous biomarkers is that no novel single laboratory marker can diagnose, predict, and track the treatment of sepsis. The purpose of this review is to summarize several key biomarkers from recent sepsis studies.

Biomarkers for sepsis: a review with special attention to India

Sepsis is a serious infection and still a common cause of morbidity and mortality in resource-limited settings such as India. Even when microbiologic diagnostics are available, bacteremia is only identified in a proportion of patients who present with sepsis and bloodstream infections. Biomarkers have been used in a variety of disease processes and can help aid in diagnosing bacterial infections. There have been numerous biomarkers investigated to aid with diagnosis and prognostication in sepsis with the majority suffering from lack of sensitivity or specificity. Procalcitonin has been heralded as the biomarker that holds the most promise for bloodstream infections. Data are emerging in India, and in this review, we focus on the current data of biomarkers in sepsis with particular attention to how biomarkers could be used to augment diagnosis and treatment in India.

[Procalcitonin and C-reactive protein as early indicators of postoperative intra-abdominal infection after surgery for gastrointestinal cancer]

AIM

to evaluate the association between serum levels of procalcitonin and C-reactive protein, on the first 3 postoperative days, and the appearance of postoperative intra-abdominal infection.

METHOD

Prospective observational study including 67 patients operated on for colo-rectal, gastric and pancreatic cancer. Serum levels of procalcitonin and C-reactive protein were analyzed before surgery and daily until the third postoperative day. Values of procalcitonin (PCT) and C-reactive protein (CRP) were recorded as well as their accuracy for detection of postoperative intra-abdominal infection (PIAI).

RESULTS

The incidence of postoperative intra-abdominal infection was 13.4%. CRP serum levels at 72h, PCT serum levels at 24, 48 and 72h and the ratio between serum levels of CRP at 72hours and serum levels of CRP at 48hours (CRP D3/CRP D2) were significantly associated with the appearance of postoperative intra-abdominal infection. The highest sensitivity corresponded to PCT at 72hours (88.9%); the highest specificity and positive predictive value corresponded to the ratio CRP D3/CRP D2 (96.49% and 71.4%, respectively); the highest negative predictive value to procalcitonin at 72h and 24h.

CONCLUSIONS

Serum levels of PCT are significantly associated with the appearance of postoperative intra-abdominal infection. Sensitivity and predictive positive values are low, but negative predictive value is high, even at 24h after surgery.

Procalcitonin to predict bacterial coinfection in infants with acute bronchiolitis: a preliminary analysis

OBJECTIVE

The aim of this study was to conduct a preliminary analysis of serum procalcitonin (PCT) to predict bacterial coinfection in infants with acute bronchiolitis.

METHODS

Retrospective cohort chart review of 40 infants admitted with acute bronchiolitis to the pediatric intensive care unit. Logistic regression models were used to determine the association of PCT and white blood count with presence of bacterial coinfection defined by either positive culture or chest radiograph result.

RESULTS

Fifteen (38%) of 40 patients had a diagnosis of bacterial coinfection by positive culture (9/15) or chest radiograph (6/15). Procalcitonin (P < 0.0001) was significantly associated with bacterial coinfection. A cutoff value of 1.5 ng/mL had sensitivity of 0.80, specificity of 1.00, and area under the operating curve of 0.88. White blood count (P = 0.06) was borderline significant with sensitivity of 0.33, specificity of 0.96, and area under the operating curve of 0.67. Three of 15 patients were later found to have bacterial coinfection with initial PCT of less than 1.5 ng/mL. None had follow-up PCT measurements taken. Thirty-five of 40 were prescribed empiric antibiotic therapy, including 20 of 25 patients without evidence of bacterial coinfection. None had a PCT of greater than 1.5 ng/mL. If a PCT cutoff of greater than 1.5 ng/mL had been used, 57% fewer patients would have received antibiotics with a 45% reduction in antimicrobial charges.

CONCLUSIONS

An elevated PCT may assist clinicians in determining presence of bacterial coinfection at admission in infants with acute bronchiolitis. Implementation of a PCT cutoff of 1.5 ng/mL at admission may prevent unnecessary antibiotic use with associated cost savings. Serial PCT levels may increase sensitivity. Further validation is warranted.

A clinical trial comparing physician prompting with an unprompted automated electronic checklist to reduce empirical antibiotic utilization

OBJECTIVES

To determine whether face-to-face prompting of critical care physicians reduces empirical antibiotic utilization compared to an unprompted electronic checklist embedded within the electronic health record.

DESIGN

Random allocation design.

SETTING

Medical ICU with high-intensity intensivist coverage at a tertiary care urban medical center.

PATIENTS

Two hundred ninety-six critically ill patients treated with at least 1 day of empirical antibiotics.

INTERVENTIONS

For one medical ICU team, face-to-face prompting of critical care physicians if they did not address empirical antibiotic utilization during a patient's daily rounds. On a separate medical ICU team, attendings and fellows were trained once to complete an electronic health record-embedded checklist daily for each patient, including a question asking whether listed empirical antibiotics could be discontinued.

MEASUREMENTS AND MAIN RESULTS

Prompting led to a more than four-fold increase in discontinuing or narrowing of empirical antibiotics compared to use of the electronic checklist. Prompted group patients had a lower proportion of patient-days on which empirical antibiotics were administered compared to electronic checklist group patients (63.1% vs 70.0%, p = 0.002). Mean proportion of antibiotic-days on which empirical antibiotics were used was also lower in the prompted group, although not statistically significant (0.78 [0.27] vs 0.83 [0.27], p = 0.093). Each additional day of empirical antibiotics predicted higher risk-adjusted mortality (odds ratio, 1.14; 95% CI, 1.05-1.23). Risk-adjusted ICU length of stay and hospital mortality were not significantly different between the two groups.

CONCLUSIONS

Face-to-face prompting was superior to an unprompted electronic health record-based checklist at reducing empirical antibiotic utilization. Sustained culture change may have contributed to the electronic checklist having similar empirical antibiotic utilization to a prompted group in the same medical ICU 2 years prior. Future studies should investigate the integration of an automated prompting mechanism with a more generalizable electronic health record-based checklist.

Procalcitonin-guided therapy in intensive care unit patients with severe sepsis and septic shock--a systematic review and meta-analysis

Introduction

Procalcitonin (PCT) algorithms for antibiotic treatment decisions have been studied in adult patients from primary care, emergency department, and intensive care unit (ICU) settings, suggesting that procalcitonin-guided therapy may reduce antibiotic exposure without increasing the mortality rate. However, information on the efficacy and safety of this approach in the most vulnerable population of critically ill patients with severe sepsis and septic shock is missing.

Method

Two reviewers independently performed a systematic search in PubMed, Embase, ISI Web of Knowledge, BioMed Central, ScienceDirect, Cochrane Central Register of Controlled Trials, http://www.ClinicalTrials.gov and http://www.ISRCTN.org.

Eligible studies had to be randomized controlled clinical trials or cohort studies which compare procalcitonin-guided therapy with standard care in severe sepsis patients and report at least one of the following outcomes: hospital mortality, 28-day mortality, duration of antimicrobial therapy, length of stay in the intensive care unit or length of hospital stay. Disagreements about inclusion of studies and judgment of bias were solved by consensus.

Results

Finally seven studies comprising a total of 1,075 patients with severe sepsis or septic shock were included in the meta-analysis.

Both hospital mortality (RR [relative risk]: 0.91, 95%CI [confidence interval]: 0.61; 1.36) and 28-day mortality (RR: 1.02, 95%CI: 0.85; 1.23) were not different between procalcitonin-guided therapy and standard treatment groups.

Duration of antimicrobial therapy was significantly reduced in favor of procalcitonin-guided therapy (HR [hazard ratio]: 1.27, 95%CI: 1.01; 1.53). Combined estimates of the length of stay in the ICU and in hospital did not differ between groups.

Conclusion

Procalcitonin-guided therapy is a helpful approach to guide antibiotic therapy and surgical interventions without a beneficial effect on mortality. The major benefit of PCT-guided therapy consists of a shorter duration of antibiotic treatment compared to standard care.

Trials are needed to investigate the effect of PCT-guided therapy on mortality, length of ICU and in-hospital stay in severe sepsis patients.

The efficacy of procalcitonin as a biomarker in the management of sepsis: slaying dragons or tilting at windmills?

BACKGROUND

Sepsis is defined as systemic inflammatory response syndrome (SIRS) in the context of an underlying infectious process, and is associated with high rates of morbidity and mortality, particularly when initial therapy is delayed. Numerous biomarkers, including but not limited to cytokines (interleukins-2 and -6 [IL-2, IL-6] and tumor necrosis factor-α [TNF-α]), leukotrienes, acute-phase proteins (C-reactive protein [CRP]), and adhesion molecules, have been evaluated and rejected as unsuitable for the diagnosis of sepsis, predicting its severity, and guiding its treatment. Most recently, procalcitonin (PCT) has been suggested as a novel biomarker that may be useful in guiding therapeutic decision making in the management of sepsis. This article assesses critically the published literature on the clinical utility of PCT concentrations for guiding the treatment of sepsis in adult patients.

METHODS

A comprehensive search of all published studies of the use of serum concentrations of PCT to guide the treatment of sepsis in adult patients (1996 to 2011) was conducted with PubMed and Google Scholar. The search focused on the value of PCT concentrations to guide the diagnosis, prognosis, monitoring, and escalation and de-escalation of antbiotic therapy in these patients. Keywords searched included "procalcitonin," "sepsis," "sepsis biomarker," "sepsis diagnosis," "sepsis prognosis," "sepsis mortality," "antibiotic escalation," "antibiotic de-escalation," "antibiotic duration," and "antimicrobial stewardship."

RESULTS

Forty-six trials evaluating the efficacy of PCT concentrations in diagnosing sepsis have been published, with 39 of these trials yielding positive results and 7 yielding negative results. Wanner et al. published the largest study (n=405) demonstrating that peak PCT concentrations occur early after injury in both patients with sepsis and those with multiple organ dysfunction syndrome (MODS). Among 17 trials assessing the prognostic value of PCT concentrations with regard to clinical outcome and morbidity, 12 trials yielded positive results and five showed negative or equivocal results. Reith et al. published the largest study of the prognostic use of PCT concentrations (n=246), demonstrating that median PCT values on post-operative days (POD) one, four, and 10 were predictive of mortality in patients with abdominal sepsis (p<0.01). Among 14 trials of the utility of PCT concentrations for establishing an infectious cause of sepsis, 13 yielded positive results and only one yielded negative results. The largest study of this use of PCT concentrations, conducted by Baykut et al. (n=400), evaluated these concentrations in post-operative patients with infection, and demonstrated that concentrations of PCT remained elevated until POD 4, with a second increase observed between POD 4 and POD 6. In uninfected patients, PCT concentrations began to decrease on POD 2. Only a single study has assessed the utility of PCT concentrations in guiding the escalation of antibiotic therapy, and its results were negative. Specifically, Jensen et al. (n=1,200) compared a PCT-guided antibiotic escalation strategy with the standard of care for sepsis and found no difference in outcomes. They also found that the PCT group had a longer average stay in the intensive care unit (ICU), greater rates of mechanical ventilation, and a decreased estimated glomerular filtration rate (eGFR). Among four trials focusing on PCT concentrations and antibiotic de-escalation, all showed positive results with the measurement of PCT concentrations. The largest such study, by Bouadma et al. (n=621), demonstrated a four-day decrease in antibiotic duration when PCT concentrations were used to guide therapy relative to the study arm given the standard of care, with no increase in mortality (p=0.003).

CONCLUSIONS

The diagnostic value of serum PCT concentrations for discriminating among SIRS, sepsis, severe sepsis, and septic shock remains to be established. Although higher PCT concentrations suggest a systemic bacterial infection as opposed to a viral, fungal, or inflammatory etiology of sepsis, serum PCT concentrations do not correlate with the severity of sepsis or with mortality. At present, PCT concentrations are solely investigational with regard to determining the timing and appropriateness of escalation of antimicrobial therapy in sepsis. Nevertheless, serum PCT concentrations have established utility in monitoring the clinical response to medical and surgical therapy for sepsis, and in surveillance for the development of sepsis in burn and ICU patients, and may have a role in guiding the de-escalation of antibiotic therapy.

Procalcitonin versus C-reactive protein for guiding antibiotic therapy in sepsis: a randomized trial

OBJECTIVE

We sought to evaluate whether procalcitonin was superior to C-reactive protein in guiding antibiotic therapy in intensive care patients with sepsis.

DESIGN

Randomized open clinical trial.

SETTING

Two university hospitals in Brazil.

PATIENTS

Patients with severe sepsis or septic shock.

INTERVENTIONS

Patients were randomized in two groups: the procalcitonin group and the C-reactive protein group. Antibiotic therapy was discontinued following a protocol based on serum levels of these markers, according to the allocation group. The procalcitonin group was considered superior if the duration of antibiotic therapy was at least 25% shorter than in the C-reactive protein group. For both groups, at least seven full-days of antibiotic therapy were ensured in patients with Sequential Organ Failure Assessment greater than 10 and/or bacteremia at inclusion, and patients with evident resolution of the infectious process had antibiotics stopped after 7 days, despite biomarkers levels.

MEASUREMENTS AND MAIN RESULTS

Ninety-four patients were randomized: 49 patients to the procalcitonin group and 45 patients to the C-reactive protein group. The mean age was 59.8 (SD, 16.8) years. The median duration of antibiotic therapy for the first episode of infection was 7.0 (Q1-Q3, 6.0-8.5) days in the procalcitonin group and 6.0 (Q1-Q3, 5.0-7.0) days in the C-reactive protein group (p=0.13), with a hazard ratio of 1.206 (95% CI, 0.774-1.3; p=0.13). Overall, protocol overruling occurred in only 13 (13.8%) patients. Twenty-one patients died in each group (p=0.836).

CONCLUSIONS

C-reactive protein was as useful as procalcitonin in reducing antibiotic use in a predominantly medical population of septic patients, causing no apparent harm.

Role of biomarkers in sepsis care

Sepsis is one of the leading causes of mortality and morbidity, even with the current availability of extended-spectrum antibiotics and advanced medical care. Biomarkers offer a tool in facilitating early diagnosis, in identifying patient populations at high risk of complications, and in monitoring progression of the disease, which are critical assessments for appropriate therapy and improvement in patient outcomes. Several biomarkers are already available for clinical use in sepsis; however, their effectiveness in many instances is limited by the lack of specificity and sensitivity to characterize the presence of an infection and the complexity of the inflammatory and immune processes and to stratify patients into homogenous groups for specific treatments. Current advances in molecular techniques have provided new tools facilitating the discovery of novel biomarkers, which can vary from metabolites and chemical products present in body fluids to genes and proteins in circulating blood cells. The purpose of this review was to examine the current status of sepsis biomarkers, with special emphasis on emerging markers, which are undergoing validation and may transition into clinical practice for their informative value in diagnosis, prognosis, or response to therapy. We will also discuss the new concept of combination biomarkers and biomarker risk models, their existing challenges, and their potential use in the daily management of patients with sepsis.

Procalcitonin biomarker kinetics fails to predict treatment response in perioperative abdominal infection with septic shock

Introduction

Procalcitonin (PCT) biomarker is suggested to tailor antibiotic therapy in the medical intensive care unit (ICU) but studies in perioperative medicine are scarce. The aim of this study was to determine whether PCT reported thresholds are associated with the initial treatment response in perioperative septic shock secondary to intra-abdominal infection.

Methods

This single ICU, observational study included patients with perioperative septic shocks secondary to intra-abdominal infection. Demographics, PCT at days 0, 1, 3, 5, treatment response and outcome were collected. Treatment failure included death related to the initial infection, second source control treatment or a new onset intra-abdominal infection. The primary endpoint was to assess whether PCT thresholds (0.5 ng/ml or a drop from the peak of at least 80%) predict the initial treatment response.

Results

We included 101 consecutive cases. Initial treatment failed in 36 patients with a subsequent mortality of 75%. Upon admission, PCT was doubled when treatment ultimately failed (21.7 ng/ml ± 38.7 vs. 41.7 ng/ml ± 75.7; P = 0.04). Although 95% of the patients in whom PCT dropped down below 0.5 ng/ml responded to treatment, 50% of the patients in whom PCT remained above 0.5 ng/ml also responded successfully to treatment. Moreover, despite a PCT drop of at least 80%, 40% of patients had treatment failure.

Conclusions

In perioperative intra-abdominal infections with shock, PCT decrease to 0.5 ng/ml lacked sensitivity to predict treatment response and its decrease of at least 80% from its peak failed to accurately predict treatment response. Studies in perioperative severe infections are needed before using PCT to tailor antibiotic use in this population.

Pro-adrenomedullin, pro-endothelin-1, procalcitonin, C-reactive protein and mortality risk in critically ill children: a prospective study

Introduction

We tested the hypothesis that higher mid-regional pro-adrenomedullin (MR-proADM), carboxy-terminal pro-endothelin-1 (CT-proET-1), procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations would be associated with increased prediction of mortality risk scores.

Methods

Prospective observational study set in two pediatric intensive care units (PICUs). Two-hundred-thirty-eight patients were included. MR-proADM, CT-proET-1, PCT and CRP levels were compared between children with PRISM III and PIM 2 > p75 (Group A; n = 33) and the rest (Group B; n = 205).

Results

Median (range) MR-proADM levels were 1.39 nmol/L (0.52–12.67) in group A versus 0.54 (0.15–3.85) in group B (P < 0.001). CT-proET-1 levels were 172 pmol/L (27–500) versus 58 (4–447) (P < 0.001). PCT levels were 7.77 ng/mL (0.34–552.00) versus 0.28 (0.02–107.00) (P < 0.001). CRP levels were 6.23 mg/dL (0.08-28.25) versus 1.30 mg/dL (0.00-42.09) (P = 0.210). The area under the ROC curve (AUC) for the differentiation of group A and B was 0.87 (95% CI:0.81–0.821) for MR-proADM, 0.86 (95% CI:0.79–0.92) for CT-proET-1 and 0.84 (95% CI:0.74–0.94) for PCT. A MR-proADM > 0.79 nmol/L had 93% sensitivity and 76% specificity to differentiate groups, whereas a CT-proET-1 > 123 pmol/L had 77% sensitivity and 84% specificity, and a PCT concentration > 2.05 ng/mL had 80% sensitivity and specificity.

Conclusions

In critically ill children, high levels of MR-proADM, CT-proET-1 and PCT were associated with increased prediction of mortality risk scores. MR-proADM, CT-proET-1 and PCT concentrations higher than 0.80 nmol/L, 123 pmol/L and 2 ng/mL, respectively, could be used by clinicians to identify critically ill children at higher prediction of risk death scores.

[Role of plasma procalcitonin in the diagnosis of ventilator-associated pneumonia: systematic review and metaanalysis]

OBJECTIVE

To determine the role of plasma procalcitonin (PCT) levels in diagnosing ventilator-associated pneumonia.

DESIGN

A systematic review of publications prospectively assessing the diagnostic role of PCT in ventilator-associated pneumonia was carried out. The search was performed using Medline, Embase, the Cochrane Collaboration and MEDION, with reviewing of the references of retrieved articles. We extracted data that allowed the calculation of sensitivity, specificity, likelihood ratios and diagnostic odds ratio. Intervention Metaregression was performed to determine whether exposure to previous antibiotic treatment, the time to occurrence of ventilator-associated pneumonia and the type of patients had an impact upon the diagnostic performance of procalcitonin.

RESULTS

Seven studies were considered (373 patients, 434 episodes). We found no publication bias or threshold effect. High plasma PCT levels were associated to an increased risk of suffering ventilator-associated pneumonia (OR: 8.39; 95% CI: 5.4-12.6). The pooled data on sensitivity, specificity, positive and negative likelihood ratio, and diagnostic odds ratio found were 76% (69-82), 79% (74-84), 4.35 (2.48-7.62), 0.26 (0.15-0.46) and 17.9 (10.1-31.7), respectively. Diagnostic yield was modified by prior exposure to antibiotics (rDOR 0.11, 0.02-0.069), but not by the type of critically ill patient or the time to occurrence of ventilator-associated pneumonia.

CONCLUSIONS

Our results suggest that PCT provides additional information on the risk of VAP. Inclusion of PCT in diagnostic algorithms could improve their effectiveness.

Procalcitonin-guided antibiotic therapy: a systematic review and meta-analysis

BACKGROUND

The utility of procalcitonin to manage patients with infections is unclear. A systematic review of comparative studies using procalcitonin-guided antibiotic therapy in patients with infections was performed.

METHODS

Randomized, controlled trials comparing procalcitonin-guided initiation, intensification, or discontinuation of antibiotic therapy to clinically guided therapy were included. Outcomes were antibiotic usage, morbidity, and mortality. MEDLINE, EMBASE, the Cochrane Database, National Institute for Clinical Excellence, the National Guideline Clearinghouse, and the Health Technology Assessment Programme were searched from January 1, 1990 to December 16, 2011.

RESULTS

Eighteen randomized, controlled trials were included. Data were pooled into clinically similar patient populations. In adult intensive care unit (ICU) patients, procalcitonin-guided discontinuation of antibiotics reduced antibiotic duration by 2.05 days (95% confidence interval [CI]: -2.59 to -1.52) without increasing morbidity or mortality. In contrast, procalcitonin-guided intensification of antibiotics in adult ICU patients increased antibiotic usage and morbidity. In adult patients with respiratory tract infections, procalcitonin guidance significantly reduced antibiotic duration by 2.35 days (95% CI: -4.38 to -0.33), antibiotic prescription rate by 22% (95% CI: -41% to -4%), and total antibiotic exposure without affecting morbidity or mortality. A single, good quality study of neonates with suspected sepsis demonstrated reduced antibiotic duration by 22.4 hours (P = 0.012) and reduced the proportion of neonates on antibiotics for ≥ 72 hours by 27% (P = 0.002) with procalcitonin guidance.

CONCLUSION

Procalcitonin guidance can safely reduce antibiotic usage when used to discontinue antibiotic therapy in adult ICU patients and when used to initiate or discontinue antibiotics in adult patients with respiratory tract infections.

Role of biomarkers in the management of antibiotic therapy: an expert panel review II: clinical use of biomarkers for initiation or discontinuation of antibiotic therapy

Biomarker-guided initiation of antibiotic therapy has been studied in four conditions: acute pancreatitis, lower respiratory tract infection (LRTI), meningitis, and sepsis in the ICU. In pancreatitis with suspected infected necrosis, initiating antibiotics best relies on fine-needle aspiration and demonstration of infected material. We suggest that PCT be measured to help predict infection; however, available data are insufficient to decide on initiating antibiotics based on PCT levels. In adult patients suspected of community-acquired LRTI, we suggest withholding antibiotic therapy when the serum PCT level is low (<0.25 ng/mL); in patients having nosocomial LRTI, data are insufficient to recommend initiating therapy based on a single PCT level or even repeated measurements. For children with suspected bacterial meningitis, we recommend using a decision rule as an aid to therapeutic decisions, such as the Bacterial Meningitis Score or the Meningitest®; a single PCT level ≥0.5 ng/mL also may be used, but false-negatives may occur. In adults with suspected bacterial meningitis, we suggest integrating serum PCT measurements in a clinical decision rule to help distinguish between viral and bacterial meningitis, using a 0.5 ng/mL threshold. For ICU patients suspected of community-acquired infection, we do not recommend using a threshold serum PCT value to help the decision to initiate antibiotic therapy; data are insufficient to recommend using PCT serum kinetics for the decision to initiate antibiotic therapy in patients suspected of ICU-acquired infection. In children, CRP can probably be used to help discontinue therapy, although the evidence is limited. In adults, antibiotic discontinuation can be based on an algorithm using repeated PCT measurements. In non-immunocompromised out- or in- patients treated for RTI, antibiotics can be discontinued if the PCT level at day 3 is < 0.25 ng/mL or has decreased by >80-90%, whether or not microbiological documentation has been obtained. For ICU patients who have nonbacteremic sepsis from a known site of infection, antibiotics can be stopped if the PCT level at day 3 is < 0.5 ng/mL or has decreased by >80% relative to the highest level recorded, irrespective of the severity of the infectious episode; in bacteremic patients, a minimal duration of therapy of 5 days is recommended.

Procalcitonin: Does It Have a Role in the Diagnosis, Management and Prognosis of Patients with Sepsis?

There is growing interest in the use of procalcitonin as a biomarker of bacterial infection. In particular, focus has been on the use of procalcitonin to facilitate a more timely diagnosis of sepsis and to guide the appropriate duration of antibiotic therapy. However, there is a lack of consensus in the literature concerning the role of measuring procalcitonin levels in clinical practice. This article reviews the evidence surrounding the utility of this biomarker for patients with sepsis in the intensive care environment. It is concluded that raised procalcitonin levels add little as a diagnostic criterion, however evidence supports the incorporation of procalcitonin-based algorithms relating to antibiotic stewardship in this patient population.

Can we improve the outcomes of pediatric congenital heart disease survivors?

Appreciating the complexity and evolving pathophysiology after palliation of CHD is critical to improving the outcome. Despite a growing patient population because of greater survival over the years, detailed data on the long-term outcomes of these patients is surprisingly sparse. The establishment in 2001 of the Pediatric Heart Network by the National Heart, Lung and Blood Institute has provided a collaborative multicenter platform to conduct large trials in CHD and to characterize outcomes. This chapter has emphasized how CHD care spans the continuum from fetal life to adulthood. Current research efforts aspire to better characterize short-term and long-term outcomes, continue advancement of technologies to better diagnose and treat CHD, and to elucidate the role of genetics and biomarkers in predicting outcome. Focused studies on variations in perioperative practice and quality will help us provide better clinical outcomes for CHD survivors.

Plasma bacterial and mitochondrial DNA distinguish bacterial sepsis from sterile systemic inflammatory response syndrome and quantify inflammatory tissue injury in nonhuman primates

Systemic inflammatory response syndrome (SIRS) is a fundamental host response common to bacterial infection and sterile tissue injury. Systemic inflammatory response syndrome can cause organ dysfunction and death, but its mechanisms are incompletely understood. Moreover, SIRS can progress to organ failure or death despite being sterile or after control of the inciting infection. Biomarkers discriminating between sepsis, sterile SIRS, and postinfective SIRS would therefore help direct care. Circulating mitochondrial DNA (mtDNA) is a damage-associated molecular pattern reflecting cellular injury. Circulating bacterial 16S DNA (bDNA) is a pathogen-associated pattern (PAMP) reflecting ongoing infection. We developed quantitative polymerase chain reaction assays to quantify these markers, and predicting their plasma levels might help distinguish sterile injury from infection. To study these events in primates, we assayed banked serum from Papio baboons that had undergone a brief challenge of intravenous Bacillus anthracis delta Sterne (modified to remove toxins) followed by antibiotics (anthrax) that causes organ failure and death. To investigate the progression of sepsis to "severe" sepsis and death, we studied animals where anthrax was pretreated with drotrecogin alfa (activated protein C), which attenuates sepsis in baboons. We also contrasted lethal anthrax bacteremia against nonlethal E. coli bacteremia and against sterile tissue injury from Shiga-like toxin 1. Bacterial DNA and mtDNA levels in timed samples were correlated with blood culture results and assays of organ function. Sterile injury by Shiga-like toxin 1 increased mtDNA, but bDNA was undetectable: consistent with the absence of infection. The bacterial challenges caused parallel early bDNA and mtDNA increases, but bDNA detected pathogens even after bacteria were undetectable by culture. Sublethal E. coli challenge only caused transient rises in mtDNA consistent with a self-limited injury. In lethal anthrax challenge (n = 4), bDNA increased transiently, but mtDNA levels remained elevated until death, consistent with persistent septic tissue damage after bacterial clearance. Critically, activated protein C pretreatment (n = 4) allowed mtDNA levels to decay after bacterial clearance with sparing of organ function and survival. In summary, host tissue injury correlates with mtDNA whether infective or sterile. Mitochondrial DNA and bDNA polymerase chain reactions can quantify tissue injury incurred by septic or sterile mechanisms and suggest the source of SIRS of unknown origin.

Procalcitonin as a biomarker of infectious diseases

Traditional biomarkers, including C-reactive protein, leukocytes, erythrocyte sedimentation rate, and clinical signs and symptoms, are not sufficiently sensitive or specific enough to guide treatment decisions in infectious febrile diseases. Procalcitonin (PCT) is synthesized by a large number of tissues and organs in response to invasion by pathogenic bacteria, fungi, and some parasites. A growing body of evidence supports the use of PCT as a marker to improve the diagnosis of bacterial infections and to guide antibiotic therapy. Clinically, PCT levels may help guide the need for empirical antibiotic therapy, source control for infections, and duration of antibiotic therapy. The aim of this review is to summarize the current evidence for PCT in different infections and clinical settings, and to discuss the reliability of this marker in order to provide physicians with an overview of the potential for PCT to guide antibiotic therapy.

Diagnostic value of soluble triggering receptor expressed on myeloid cells-1 in critically-ill, postoperative patients with suspected sepsis

INTRODUCTION

: The lack of specific clinical manifestations for sepsis frequently leads to delayed diagnosis. Identification of sensitive and specific indicators that can be easily assessed, accurately reflect infection severity and prognosis and are clinically important in the differential diagnosis of sepsis, is of great significance. The purpose of this study was to evaluate the diagnostic and prognostic value of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in high selected, mostly postoperative patients with suspicion of sepsis.

METHODS

: Fifty-two consecutive patients hospitalized in a surgical intensive care unit with suspicion of infection included 14 patients with systemic inflammatory response syndrome (SIRS), 9 patients with sepsis, 14 patients with severe sepsis and 15 patients with septic shock. Within 12 hours after enrollment, plasma levels of sTREM-1, procalcitonin (PCT), tumor necrosis factor (TNF)-α, interleukin-6 and C-reactive protein were measured and compared between subgroups to elucidate their diagnostic and prognostic values.

RESULTS

: Plasma sTREM-1 levels were higher in patients with sepsis than in patients with SIRS (111.7 versus 64.1 pg/mL, P < 0.05), with sensitivity, specificity and a predictive value higher than those of PCT and TNF-α. Plasma sTREM-1 levels were significantly different between the sepsis, severe sepsis and septic shock subgroups (P < 0.001). For the receiver operating characteristic for predicting death, the area under the curve of sTREM-1 was 0.861, similar to that of TNF-α, blood lactate and PCT (0.848, 0.719 and 0.706, respectively).

CONCLUSIONS

: In postoperative patients, plasma levels of sTREM-1 and TNF-α could differentiate sepsis from SIRS. sTREM levels also reflected the severity of sepsis and were noninferior for prognosis compared with other biochemical indexes.

Stop Antibiotics on guidance of Procalcitonin Study (SAPS): a randomised prospective multicenter investigator-initiated trial to analyse whether daily measurements of procalcitonin versus a standard-of-care approach can safely shorten antibiotic duration in intensive care unit patients--calculated sample size: 1816 patients

BACKGROUND

Unnecessary long-term use of broad-spectrum antibiotics is linked to the emergence and selection of resistant bacteria, prolonged hospitalisation and increased costs. Several clinical trials indicate that the biomarker procalcitonin (PCT) can guide antibiotic therapy. Some of these trials have shown a promising reduction in the number of antibiotic prescriptions, duration of antibiotic therapy and even length of stay in the ICU, although their size and selection criteria limit their external validity. The objectives of the Stop Antibiotics on guidance of Procalcitonin Study (SAPS) are to evaluate whether daily PCT can improve "real-life" antibiotic use in Dutch ICU's by reduction of the duration of antibiotic treatment without an increase of recurrent infections and mortality.

METHODS/DESIGN

Multicenter randomised controlled intervention trial. Powered for superiority of the primary efficacy endpoint and non-inferiority on the primary safety endpoints (non-inferiority margin is set on 8%).

INCLUSION CRITERIA

(1) ICU-patients aged ≥18 years and (2) receiving antibiotics for a presumed or proven infection and (3) signed informed consent.

EXCLUSION CRITERIA

(1) patients who require prolonged antibiotic therapy, (2) suffer from Mycobacterium tuberculosis, (3) cystic fibrosis, (4) viral or parasitic infections and (5) those that are severely immunocompromised or (6) moribund.The intervention consists solely of an advice to discontinue antibiotic treatment in case PCT has decreased by more than 80% of its peak level (relative stopping threshold) or decrease below a value of 0.5 ng/ml (absolute stopping threshold).The study hypothesis is that PCT-guided therapy is non-inferior to standard care based on implemented guidelines and local expertise, whilst reducing antibiotic usage. Computerised 1:1 randomisation will allocate 908 patients per arm. Arm 1: standard of care. Arm 2: procalcitonin-guided therapy. The primary efficacy endpoint is consumption of antibiotics expressed as the defined daily dosage and duration of antibiotic therapy expressed in days of therapy. This trial is designed to shorten antibiotics safely, therefore the primary safety endpoint is mortality measured at 28 day and 1 year.

DISCUSSION

This will be the largest procalcitonin-guided antibiotic intervention trial in ICU setting thus far. Currently 1600 of the planned 1816 patients are randomised (November 2012). The first interim analysis has passed without any safety or futility issues.

TRIAL REGISTRATION

Trial registration number at www.clinicaltrials.gov: Id. Nr. NCT01139489, at www.trialregister.nl: Id.nr. NTR1861.

Procalcitonin-guided algorithm to reduce length of antibiotic therapy in patients with severe sepsis and septic shock

BACKGROUND

Procalcitonin (PCT)-protocols to guide antibiotic treatment in severe infections are known to be effective. But less is known about the long-term effects of such protocols on antibiotic consumption under real life conditions. This retrospective study analyses the effects on antibiotic use in patients with severe sepsis and septic shock after implementation of a PCT-protocol.

METHODS

We conducted a retrospective ICU-database search for adult patients between 2005 and 2009 with sepsis and organ dysfunction who where treated accordingly to a PCT-guided algorithm as follows: Daily measurements of PCT (BRAHMS PCT LIA(®); BRAHMS Aktiengesellschaft, Hennigsdorf, Germany). Antibiotic therapy was discontinued if 1) clinical signs and symptoms of infection improved and PCT decreased to ≤1 ng/ml, or 2) if the PCT value was >1 ng/ml, but had dropped to 25-35% of the initial value within three days. The primary outcome parameters were: antibiotic days on ICU, ICU re-infection rate, 28-day mortality rate, length of stay (LOS) in ICU, mean antibiotic costs (per patient) and ventilation hours. Data from 141 patients were included in our study. Primary outcome parameters were analysed using covariance analyses (ANCOVA) to control for effects by gender, age, SAPS II, APACHE II and effective cost weight.

RESULTS

From baseline data of 2005, duration of antibiotic therapy was reduced by an average of 1.0 day per year from 14.3 ±1.2 to 9.0 ±1.7 days in 2009 (p=0.02). ICU re-infection rate was decreased by yearly 35.1% (95% CI -53 to -8.5; p=0.014) just as ventilation hours by 42 hours per year (95% CI -72.6 to -11.4; p=0.008). ICU-LOS was reduced by 2.7 days per year (p<0.001). Trends towards an average yearly reduction of 28-day mortality by -22.4% (95% CI -44.3 to 8.1; p=0.133) and mean cost for antibiotic therapy/ patient by -14.3 Euro (95% CI -55.7 to 27.1) did not reach statistical significance.

CONCLUSIONS

In a real-life clinical setting, implementation of a PCT-protocol was associated with a reduced duration of antibiotic therapy in septic ICU patients without compromising clinical or economical outcomes. GERMAN CLINICAL TRIALS REGISTER: DRKS00003490.

The use of procalcitonin as a marker of sepsis in children

OBJECTIVE

Sepsis is a life-threatening disease which is associated with high rates of morbidity and mortality. The critically ill patients often manifest a Systemic Inflammatory Response Syndrome (SIRS) which is independent of an infection. The early diagnosis of different severities of sepsis is important for an early implementation of the specific therapies. Our objective was to evaluate the diagnostic and the prognostic values of blood Procalcitonin (PCT) in cases of bacterial septicaemia in children.

METHODS

The total sample comprised of 150 subjects who were admitted to the ICU with septicaemia and 50 normal, healthy, age and sex matched children. The first sample was collected at the time of admission, before the start of the antibiotic therapy (T0). A second sample was collected at 24 hours (T24) and a final sample was collected at 96 hours (T96). A PCT value of > 0.5ng/ml was accepted as positive.

RESULTS

63% of the children who were diagnosed with a bacterial aetiology showed detectable blood PCT levels with higher concentrations, while in the children who were diagnosed with a viral aetiology, only 22.2 % had detectable PCT levels, but in lower concentrations. The mean percentage reduction in the PCT value among the bacterial infection subjects was 44.39 ± 41.82 as compared to that in the viral infection subjects (5.71 ± 26.68) and in the subjects where the aetiology was not established (5.71 ± 26.68).

CONCLUSION

The results which were obtained in our study con- firmed that the PCT levels were a better marker for the bacterial infections. The PCT measurements may be used as a guide to the antibiotic therapy in critically ill children with suspected sepsis.

New approaches to sepsis: molecular diagnostics and biomarkers

Sepsis is among the most common causes of death in hospitals. It arises from the host response to infection. Currently, diagnosis relies on nonspecific physiological criteria and culture-based pathogen detection. This results in diagnostic uncertainty, therapeutic delays, the mis- and overuse of antibiotics, and the failure to identify patients who might benefit from immunomodulatory therapies. There is a need for new sepsis biomarkers that can aid in therapeutic decision making and add information about screening, diagnosis, risk stratification, and monitoring of the response to therapy. The host response involves hundreds of mediators and single molecules, many of which have been proposed as biomarkers. It is, however, unlikely that one single biomarker is able to satisfy all the needs and expectations for sepsis research and management. Among biomarkers that are measurable by assays approved for clinical use, procalcitonin (PCT) has shown some usefulness as an infection marker and for antibiotic stewardship. Other possible new approaches consist of molecular strategies to improve pathogen detection and molecular diagnostics and prognostics based on transcriptomic, proteomic, or metabolic profiling. Novel approaches to sepsis promise to transform sepsis from a physiologic syndrome into a group of distinct biochemical disorders and help in the development of better diagnostic tools and effective adjunctive sepsis therapies.

Small studies may overestimate the effect sizes in critical care meta-analyses: a meta-epidemiological study

INTRODUCTION

Small-study effects refer to the fact that trials with limited sample sizes are more likely to report larger beneficial effects than large trials. However, this has never been investigated in critical care medicine. Thus, the present study aimed to examine the presence and extent of small-study effects in critical care medicine.

METHODS

Critical care meta-analyses involving randomized controlled trials and reported mortality as an outcome measure were considered eligible for the study. Component trials were classified as large (≥100 patients per arm) and small (<100 patients per arm) according to their sample sizes. Ratio of odds ratio (ROR) was calculated for each meta-analysis and then RORs were combined using a meta-analytic approach. ROR<1 indicated larger beneficial effect in small trials. Small and large trials were compared in methodological qualities including sequence generating, blinding, allocation concealment, intention to treat and sample size calculation.

RESULTS

A total of 27 critical care meta-analyses involving 317 trials were included. Of them, five meta-analyses showed statistically significant RORs <1, and other meta-analyses did not reach a statistical significance. Overall, the pooled ROR was 0.60 (95% CI: 0.53 to 0.68); the heterogeneity was moderate with an I2 of 50.3% (chi-squared = 52.30; P = 0.002). Large trials showed significantly better reporting quality than small trials in terms of sequence generating, allocation concealment, blinding, intention to treat, sample size calculation and incomplete follow-up data.

CONCLUSIONS

Small trials are more likely to report larger beneficial effects than large trials in critical care medicine, which could be partly explained by the lower methodological quality in small trials. Caution should be practiced in the interpretation of meta-analyses involving small trials.

Pancreatic stone protein as a novel marker for neonatal sepsis

PURPOSE

Early-onset sepsis (EOS) is one of the main causes for the admission of newborns to the neonatal intensive care unit. However, traditional infection markers are poor diagnostic markers of EOS. Pancreatic stone protein (PSP) is a promising sepsis marker in adults. The aim of this study was to investigate whether determining PSP improves the diagnosis of EOS in comparison with other infection markers.

METHODS

This was a prospective multicentre study involving 137 infants with a gestational age of >34 weeks who were admitted with suspected EOS. PSP, procalcitonin (PCT), soluble human triggering receptor expressed on myeloid cells-1 (sTREM-1), macrophage migration inhibitory factor (MIF) and C-reactive protein (CRP) were measured at admission. Receiver-operating characteristic (ROC) curve analysis was performed.

RESULTS

The level of PSP in infected infants was significantly higher than that in uninfected ones (median 11.3 vs. 7.5 ng/ml, respectively; p = 0.001). The ROC area under the curve was 0.69 [95 % confidence interval (CI) 0.59-0.80; p < 0.001] for PSP, 0.77 (95 % CI 0.66-0.87; p < 0.001) for PCT, 0.66 (95 % CI 0.55-0.77; p = 0.006) for CRP, 0.62 (0.51-0.73; p = 0.055) for sTREM-1 and 0.54 (0.41-0.67; p = 0.54) for MIF. PSP independently of PCT predicted EOS (p < 0.001), and the use of both markers concomitantly significantly increased the ability to diagnose EOS. A bioscore combining PSP (>9 ng/ml) and PCT (>2 ng/ml) was the best predictor of EOS (0.83; 95 % CI 0.74-0.93; p < 0.001) and resulted in a negative predictive value of 100 % and a positive predictive value of 71 %.

CONCLUSIONS

In this prospective study, the diagnostic performance of PSP and PCT was superior to that of traditional markers and a combination bioscore improved the diagnosis of sepsis. Our findings suggest that PSP is a valuable biomarker in combination with PCT in EOS.

Procalcitonin-guided antibiotic use in acute exacerbations of idiopathic pulmonary fibrosis

OBJECT

To assess the clinical value of procalcitonin to guide antibiotic therapy in acute exacerbations of idiopathic pulmonary fibrosis.

METHODS

Patients with acute exacerbations of idiopathic pulmonary fibrosis were randomly assigned to the procalcitonin-guided group (antibiotic use guided by a procalcitonin threshold of 0.25 ng/ml) or the routine treatment group (antibiotic use according to routine practice). Follow up of clinical outcomes were assessed at baseline and 30 days later.

RESULTS

Baseline characteristics including demographics, clinical characteristics and laboratory results were similar between groups. PCT guidance resulted in a significant reduction of antibiotic treatment duration (8.7 ± 6.6 compared to 14.2 ± 5.2 days in the routine treatment group). Fewer patients were exposed to antibiotics treatment in the PCT group (26 patients) compared with the control group (35 patients). Treatment success, mortality rate, days of hospitalization and ventilation therapy were similar between the two groups.

CONCLUSION

Procalcitonin-guided antibiotic therapy of patients with acute exacerbation of idiopathic pulmonary fibrosis may result in reduced exposure to antibiotics without adversely affecting patient outcomes.

The utility of procalcitonin in critically ill trauma patients

BACKGROUND

Procalcitonin (PCT), the prohormone of calcitonin, has an early and highly specific increase in response to systemic bacterial infection. The objectives of this study were to determine the natural history of PCT for patients with critical illness and trauma, the utility of PCT as a marker of sepsis versus systemic inflammatory response syndrome (SIRS), and the association of PCT level with mortality.

METHODS

PCT assays were done on eligible patients with trauma admitted to the trauma intensive care unit (ICU) of a Level I trauma center from June 2009 to June 2010, at hours 0, 6, 12, 24, and daily until discharge from ICU or death. Patients were retrospectively diagnosed with SIRS or sepsis by researchers blinded to PCT results.

RESULTS

A total of 856 PCT levels from 102 patients were analyzed, with mean age of 49 years, 63% male, 89% blunt trauma, mean Injury Severity Score of 21, and hospital mortality of 13%. PCT concentration for patients with sepsis, SIRS, and neither were evaluated. Mean PCT levels were higher for patients with sepsis versus SIRS (p < 0.0001). Patients with a PCT concentration of 5 ng/mL or higher had an increased mortality when compared with those with a PCT of less than 5 ng/mL in a univariate analysis (odds ratio, 3.65; 95% confidence interval, 1.03-12.9; p = 0.04). In a multivariate logistic analysis, PCT was found to be the only significant predictor for sepsis (odds ratio, 2.37; 95% confidence interval,1.23-4.61, p = 0.01).

CONCLUSION

PCT levels are significantly higher in ICU patients with trauma and sepsis and may help differentiate sepsis from SIRS in critical illness. An elevated PCT level was associated with increased mortality.

The neutrophil-lymphocyte count ratio in patients with community-acquired pneumonia

Study Objective

The neutrophil-lymphocyte count ratio (NLCR) has been identified as a predictor of bacteremia in medical emergencies. The aim of this study was to investigate the value of the NLCR in patients with community-acquired pneumonia (CAP).

Methods and Results

Consecutive adult patients were prospectively studied. Pneumonia severity (CURB-65 score), clinical characteristics, complications and outcomes were related to the NLCR and compared with C-reactive protein (CRP), neutrophil count, white blood cell (WBC) count. The study cohort consisted of 395 patients diagnosed with CAP. The mean age of the patients was 63.4±16.0 years. 87.6% (346/395) of the patients required hospital admission, 7.8% (31/395) patients were admitted to the Intensive Care Unit (ICU) and 5.8% (23/395) patients of the study cohort died. The NLCR was increased in all patients, predicted adverse medical outcome and consistently increased as the CURB-65 score advanced. NLCR levels (mean ± SD) were significantly higher in non-survivors (23.3±16.8) than in survivors (13.0±11.4). The receiver-operating characteristic (ROC) curve for NLCR predicting mortality showed an area under the curve (AUC) of 0.701. This was better than the AUC for the neutrophil count, WBC count, lymphocyte count and CRP level (0.681, 0.672, 0.630 and 0.565, respectively).

Conclusion

Admission NLCR at the emergency department predicts severity and outcome of CAP with a higher prognostic accuracy as compared with traditional infection markers.

Evaluation of a polymerase chain reaction assay for pathogen detection in septic patients under routine condition: an observational study

Background

Treatment of septic shock relies on appropriate antimicrobial therapy. Current culture based methods deliver final results after days, which may delay potentially lifesaving adjustments in antimicrobial therapy. This study was undertaken to compare PCR with blood culture results under routine conditions regarding 1. impact on antimicrobial therapy, and 2. time to result, in patients with presumed sepsis.

Methodology/Principal Findings

This was an observational study in a 50 beds ICU of a university hospital. In 245 patients with suspected sepsis, 311 concomitant blood cultures and blood for multiplex PCR (VYOO®) were obtained. 45 of 311 blood cultures (14.5%) and 94 of 311 PCRs (30.1%) were positive. However, blood culture or microbiological sampling from the presumed site of infection rarely confirmed PCR results and vice versa. Median time to positivity and interquartile range were 24.2 (18.0, 27.5) hours for the PCR and 68 (52.2, 88.5) hours for BC (p<0.01). PCR median time to result was dependent on technician availability (53.5 hours on Saturdays, 7.2 hours under optimal logistic conditions). PCR results showed good correlation with procalcitonin (p<0.001). In 34% of patients with positive PCRs antimicrobial therapy was considered inadequate according to assessment of clinical arbitrators including 5 patients with vancomycin-resistant enterococci (VRE), 3 cases with multiresistant staphylococci, and 4 patients with fungi.

Conclusions

The results of this observational study support the hypothesis that PCR results are available faster, are more frequently positive, and may result in earlier adjustment of antimicrobial therapy. However, shorter time to result can only be fully exploited when the laboratory is adequately staffed for a 24 hour/7 day service, or when point of care/automated assay systems become available.

Rapid response team-triggered procalcitonin measurement predicts infectious intensive care unit transfers*

OBJECTIVE

Determine if procalcitonin at the time of initial rapid response team activation identifies patients who are likely to need subsequent intensive care unit transfer.

DESIGN

Prospective observational cohort study.

SETTING

Urban, tertiary care hospital with rapid response team activation through an electronic modified early warning score.

PATIENTS

One hundred nineteen oncology and 100 consecutive non-oncology patients after initial rapid response team visit precipitated by an elevated electronic modified early warning score were recruited. Rapid response team activations by request of nursing or for other reasons were not studied. Five oncology patients seen by a rapid response team for complications of interleukin-2 therapeutic infusions were subsequently excluded.

INTERVENTIONS

Residual serum from the next ordered clinical test (within 12 hrs) was retrieved, frozen, and stored for procalcitonin determination. A second sample 12-24 hrs after the initial specimen was also retrieved if available and if the patient had not yet been transferred to the intensive care unit.

MEASUREMENTS AND MAIN RESULTS

Seventy-three patients (33%) were transferred to the intensive care unit. Rapid response team activations that did not result in intensive care unit transfer had significantly lower procalcitonin levels (median 0.28 ng/mL [interquartile range 0.09-1.24]) than those that resulted in intensive care unit transfer (median 0.51 ng/mL [interquartile range 0.11-1.97], p = .0001) but the area under the receiver operating curve was only 0.656. The change in procalcitonin level in patients with intensive care unit transfers was very heterogeneous but was significantly increased compared to the change in patients not transferred to the intensive care unit. Procalcitonin levels for intensive care unit transfers for probable or definite infection were 2.28 ng/mL [interquartile range 0.68-8.05], and were significantly greater than rapid response team visits that did not result in transfer (p = .0001). The difference between infectious and noninfectious intensive care unit transfers (0.95 ng/mL [interquartile range 0.26-1.89]) was also significant (p = .03). The procalcitonin levels of patients with noninfectious intensive care unit transfers were also different than the levels of patients who never transferred (p = .04).

CONCLUSIONS

Preliminary results suggest procalcitonin levels in patients at the time of initial visit by a rapid response team correlate with the need for subsequent intensive care unit transfer, particularly for infectious reasons.

Procalcitonin to guide initiation and duration of antibiotic treatment in acute respiratory infections: an individual patient data meta-analysis

BACKGROUND

Procalcitonin algorithms may reduce antibiotic use for acute respiratory tract infections (ARIs). We undertook an individual patient data meta-analysis to assess safety of this approach in different ARI diagnoses and different clinical settings.

METHODS

We identified clinical trials in which patients with ARI were assigned to receive antibiotics based on a procalcitonin algorithm or usual care by searching the Cochrane Register, MEDLINE, and EMBASE. Individual patient data from 4221 adults with ARIs in 14 trials were verified and reanalyzed to assess risk of mortality and treatment failure-overall and within different clinical settings and types of ARIs.

RESULTS

Overall, there were 118 deaths in 2085 patients (5.7%) assigned to procalcitonin groups compared with 134 deaths in 2126 control patients (6.3%; adjusted odds ratio, 0.94; 95% confidence interval CI, .71-1.23)]. Treatment failure occurred in 398 procalcitonin group patients (19.1%) and in 466 control patients (21.9%; adjusted odds ratio, 0.82; 95% CI, .71-.97). Procalcitonin guidance was not associated with increased mortality or treatment failure in any clinical setting or ARI diagnosis. Total antibiotic exposure per patient was significantly reduced overall (median [interquartile range], from 8 [5-12] to 4 [0-8] days; adjusted difference in days, -3.47 [95% CI, -3.78 to -3.17]) and across all clinical settings and ARI diagnoses.

CONCLUSIONS

Use of procalcitonin to guide initiation and duration of antibiotic treatment in patients with ARIs was effective in reducing antibiotic exposure across settings without an increase in the risk of mortality or treatment failure. Further high-quality trials are needed in critical-care patients.

Predictors of survival in sepsis: what is the best inflammatory marker to measure?

PURPOSE OF REVIEW

Sepsis is relevant due to its high morbidity and mortality. For both sepsis diagnosis and outcome prediction many biomarkers have been described in the literature. Most of these markers are objects of scientific interest rather than being introduced into daily clinical practice. However, due to their unspecific character and their insufficient predictive value for the individual person, research focus is still on new aspects in sepsis-related biomarkers.

RECENT FINDINGS

Beyond the widely used acute-phase proteins C-reactive protein (CRP) and procalcitonin (PCT), many new molecules have been studied deriving from different organs or cells affected, due to the systemic nature of sepsis. Cytokines, coagulation factors/characteristics, vasoactive hormones, and several others have been recently proved to be relevant in sepsis syndrome and probably useful for outcome prediction. However, single time point measurements may be less predictive than consideration of the time-dependent course of parameters. Clinical decision just based on a biomarker is still not feasible because of the huge inter-individual differences in the inflammatory response.

SUMMARY

Many biomarkers display relevant correlation with the clinical outcome of patients with severe sepsis and septic shock. Consideration of their time courses may be more reliable than absolute levels. Clinical decision should not be based only on biomarkers but organ dysfunctions, for example, should also be taken into account.

Empiric antibiotic, mechanical ventilation, and central venous catheter duration as potential factors mediating the effect of a checklist prompting intervention on mortality: an exploratory analysis

Background

Checklists are clinical decision support tools that improve process of care and patient outcomes. We previously demonstrated that prompting critical care physicians to address issues on a daily rounding checklist that were being overlooked reduced utilization of empiric antibiotics and mechanical ventilation, and reduced risk-adjusted mortality and length of stay. We sought to examine the degree to which these process of care improvements explained the observed difference in hospital mortality between the group that received prompting and an unprompted control group.

Methods

In the medical intensive care unit (MICU) of a tertiary care hospital, we conducted face-to-face prompting of critical care physicians if processes of care on a checklist were being overlooked. A control MICU team used the checklist without prompting. We performed exploratory analyses of the mediating effect of empiric antibiotic, mechanical ventilation, and central venous catheter (CVC)duration on risk-adjusted mortality.

Results

One hundred forty prompted group and 125 control group patients were included. One hundred eighty-three patients were exposed to at least one day of empiric antibiotics during MICU admission. Hospital mortality increased as empiric antibiotic duration increased (P<0.001). Prompting was associated with shorter empiric antibiotic duration and lower risk-adjusted mortality in patients receiving empiric antibiotics (OR 0.41, 95% CI 0.18-0.92, P=0.032). When empiric antibiotic duration was added to mortality models, the adjusted OR for the intervention was attenuated from 0.41 to 0.50, suggesting that shorter duration of empiric antibiotics explained 15.2% of the overall benefit of prompting. Evaluation of mechanical ventilation was limited by study size. Accounting for CVC duration changed the intervention effect slightly.

Conclusions

In this analysis, some improvement in mortality associated with prompting was explained by shorter empiric antibiotic duration. However, most of the mortality benefit of prompting was unexplained.