Procalcitonin algorithm in critically ill adults with undifferentiated infection or suspected sepsis. A randomized controlled trial

Biomarker-guided antibiotic therapy-strengths and limitations

Biomarkers as C-reactive protein (CRP) and procalcitonin (PCT) emerged as tools to help clinicians to diagnose infection and to properly initiate and define the duration of antibiotic therapy. Several randomized controlled trials, including adult critically ill patients, showed that PCT-guided antibiotic stewardship was repeatedly associated with a decrease in the duration of antibiotic therapy with no apparent harm. There are however some relevant limitations in these trials namely the low rate of compliance of PCT-guided algorithms, the high rate of exclusion (without including common clinical situations and pathogens) and the long duration of antibiotic therapy in control groups. Such limitations weakened the real impact of such algorithms in the clinical decision-making process and strengthened the concept that the initiation and the duration of antibiotic therapy cannot depend solely on a biomarker. Future efforts should address these limitations in order to better clarify the role of biomarkers on the complex and multifactorial issue of antibiotic management and to deeply understand its potential effect on mortality.

A Review of the Value of Procalcitonin as a Marker of Infection

Septicemia is a growing problem within the United States (US), which increases mortality and the cost of care. Procalcitonin is a pro-inflammatory marker that could be useful in the diagnosis of infection. In the past, procalcitonin levels have been evaluated to diagnose sepsis or guide antibiotic therapy, but it was not determined if it would differentiate between sepsis and other causes of inflammation. Studies reviewed here showed procalcitonin to be a useful biomarker as an indication of bacterial infection. Infections can be diagnosed earlier and managed appropriately to avoid progression to septicemia, reduce mortality, and overall medical costs.

Interventions to improve antibiotic prescribing practices for hospital inpatients

BACKGROUND

Antibiotic resistance is a major public health problem. Infections caused by multidrug-resistant bacteria are associated with prolonged hospital stay and death compared with infections caused by susceptible bacteria. Appropriate antibiotic use in hospitals should ensure effective treatment of patients with infection and reduce unnecessary prescriptions. We updated this systematic review to evaluate the impact of interventions to improve antibiotic prescribing to hospital inpatients.

OBJECTIVES

To estimate the effectiveness and safety of interventions to improve antibiotic prescribing to hospital inpatients and to investigate the effect of two intervention functions: restriction and enablement.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library), MEDLINE, and Embase. We searched for additional studies using the bibliographies of included articles and personal files. The last search from which records were evaluated and any studies identified incorporated into the review was January 2015.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and non-randomised studies (NRS). We included three non-randomised study designs to measure behavioural and clinical outcomes and analyse variation in the effects: non- randomised trials (NRT), controlled before-after (CBA) studies and interrupted time series (ITS) studies. For this update we also included three additional NRS designs (case control, cohort, and qualitative studies) to identify unintended consequences. Interventions included any professional or structural interventions as defined by the Cochrane Effective Practice and Organisation of Care Group. We defined restriction as 'using rules to reduce the opportunity to engage in the target behaviour (or increase the target behaviour by reducing the opportunity to engage in competing behaviours)'. We defined enablement as 'increasing means/reducing barriers to increase capability or opportunity'. The main comparison was between intervention and no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data and assessed study risk of bias. We performed meta-analysis and meta-regression of RCTs and meta-regression of ITS studies. We classified behaviour change functions for all interventions in the review, including those studies in the previously published versions. We analysed dichotomous data with a risk difference (RD). We assessed certainty of evidence with GRADE criteria.

MAIN RESULTS

This review includes 221 studies (58 RCTs, and 163 NRS). Most studies were from North America (96) or Europe (87). The remaining studies were from Asia (19), South America (8), Australia (8), and the East Asia (3). Although 62% of RCTs were at a high risk of bias, the results for the main review outcomes were similar when we restricted the analysis to studies at low risk of bias.More hospital inpatients were treated according to antibiotic prescribing policy with the intervention compared with no intervention based on 29 RCTs of predominantly enablement interventions (RD 15%, 95% confidence interval (CI) 14% to 16%; 23,394 participants; high-certainty evidence). This represents an increase from 43% to 58% .There were high levels of heterogeneity of effect size but the direction consistently favoured intervention.The duration of antibiotic treatment decreased by 1.95 days (95% CI 2.22 to 1.67; 14 RCTs; 3318 participants; high-certainty evidence) from 11.0 days. Information from non-randomised studies showed interventions to be associated with improvement in prescribing according to antibiotic policy in routine clinical practice, with 70% of interventions being hospital-wide compared with 31% for RCTs. The risk of death was similar between intervention and control groups (11% in both arms), indicating that antibiotic use can likely be reduced without adversely affecting mortality (RD 0%, 95% CI -1% to 0%; 28 RCTs; 15,827 participants; moderate-certainty evidence). Antibiotic stewardship interventions probably reduce length of stay by 1.12 days (95% CI 0.7 to 1.54 days; 15 RCTs; 3834 participants; moderate-certainty evidence). One RCT and six NRS raised concerns that restrictive interventions may lead to delay in treatment and negative professional culture because of breakdown in communication and trust between infection specialists and clinical teams (low-certainty evidence).Both enablement and restriction were independently associated with increased compliance with antibiotic policies, and enablement enhanced the effect of restrictive interventions (high-certainty evidence). Enabling interventions that included feedback were probably more effective than those that did not (moderate-certainty evidence).There was very low-certainty evidence about the effect of the interventions on reducing Clostridium difficile infections (median -48.6%, interquartile range -80.7% to -19.2%; 7 studies). This was also the case for resistant gram-negative bacteria (median -12.9%, interquartile range -35.3% to 25.2%; 11 studies) and resistant gram-positive bacteria (median -19.3%, interquartile range -50.1% to +23.1%; 9 studies). There was too much variance in microbial outcomes to reliably assess the effect of change in antibiotic use. Heterogeneity of intervention effect on prescribing outcomesWe analysed effect modifiers in 29 RCTs and 91 ITS studies. Enablement and restriction were independently associated with a larger effect size (high-certainty evidence). Feedback was included in 4 (17%) of 23 RCTs and 20 (47%) of 43 ITS studies of enabling interventions and was associated with greater intervention effect. Enablement was included in 13 (45%) of 29 ITS studies with restrictive interventions and enhanced intervention effect.

AUTHORS' CONCLUSIONS

We found high-certainty evidence that interventions are effective in increasing compliance with antibiotic policy and reducing duration of antibiotic treatment. Lower use of antibiotics probably does not increase mortality and likely reduces length of stay. Additional trials comparing antibiotic stewardship with no intervention are unlikely to change our conclusions. Enablement consistently increased the effect of interventions, including those with a restrictive component. Although feedback further increased intervention effect, it was used in only a minority of enabling interventions. Interventions were successful in safely reducing unnecessary antibiotic use in hospitals, despite the fact that the majority did not use the most effective behaviour change techniques. Consequently, effective dissemination of our findings could have considerable health service and policy impact. Future research should instead focus on targeting treatment and assessing other measures of patient safety, assess different stewardship interventions, and explore the barriers and facilitators to implementation. More research is required on unintended consequences of restrictive interventions.

Compliance with Procalcitonin Algorithm Antibiotic Recommendations for Patients in Medical Intensive Care Unit

STUDY OBJECTIVES

To describe compliance with antibiotic recommendations based on a previously published procalcitonin (PCT)-guided algorithm in clinical practice, to compare PCT algorithm compliance rates between PCT assays ordered in the antibiotic initiation setting (PCT concentration measured less than 24 hours after antibiotic initiation or before antibiotic initiation) with those in the antibiotic continuation setting (PCT concentration measured 24 hours or more after antibiotic initiation), and to evaluate patient- and PCT-related factors independently associated with algorithm compliance in patients in the medical intensive care unit (MICU).

DESIGN

Single-center retrospective cohort study.

SETTING

Large MICU in a tertiary care academic medical center.

PATIENTS

A total of 527 adults admitted to the MICU unit over a 2-year period (November 1, 2011-October 31, 2013) who had a total of 957 PCT assays performed. PCT assays whose results were determined in the MICU were allocated retrospectively to either the initiation setting cohort or the continuation setting cohort based on timing of the PCT assay.

MEASUREMENTS AND MAIN RESULTS

Each PCT assay was treated as a separate episode. Antibiotic regimens were compared between the 24-hour periods before and after the results of each PCT assay and evaluated against an algorithm to determine compliance. Clinical, laboratory, PCT-related, and microbiologic variables were assessed during the 24-hour period after the PCT assay results to determine their influence on PCT algorithm compliance. A larger proportion of PCT episodes occurred in the initiation setting (540 [56.4%]) than in the continuation setting (417 [43.5%]). Overall, compliance with PCT algorithm recommendations was low (48.5%) and not significantly different between the initiation setting and the continuation setting (49.1% vs 47.7%, p=0.678). No patient-related or PCT-related factors were independently associated with PCT algorithm compliance on multivariable logistic regression.

CONCLUSION

Compliance with PCT algorithm antibiotic recommendations in both the initiation and continuation settings was lower than that reported in published randomized studies. No factors were independently associated with PCT algorithm compliance. Institutions using PCT assays to guide antibiotic use should assess compliance with algorithm antibiotic recommendations. Inclusion of a formalized antimicrobial stewardship program along with a PCT-guided algorithm is highly recommended.

Procalcitonin-guided diagnosis and antibiotic stewardship revisited

Several controlled clinical studies have evaluated the potential of the infection biomarker procalcitonin (PCT) to improve the diagnostic work-up of patients with bacterial infections and its influence on decisions regarding antibiotic therapy. Most research has focused on lower respiratory tract infections and critically ill sepsis patients. A clinical utility for PCT has also been found for patients with urinary tract infections, postoperative infections, meningitis, and patients with acute heart failure with possible superinfection (i.e., pneumonia). In these indications, PCT levels measured on hospital admission were found to substantially reduce the initiation of antibiotic treatment in low-risk situations (i.e., bronchitis, chronic obstructive pulmonary disease exacerbation). For more severe infections (i.e., pneumonia, sepsis), antibiotic stewardship by monitoring of PCT kinetics resulted in shorter antibiotic treatment durations with early cessation of therapy. Importantly, these strategies appear to be safe without increasing the risk for mortality, recurrent infections, or treatment failures. PCT kinetics also proved to have prognostic value correlating with disease severity (i.e., pancreatitis, abdominal infection) and resolution of illness (i.e., sepsis). Although promising findings have been published in these different types of infections, there are a number of limitations regarding PCT, including suboptimal sensitivity and/or specificity, which makes a careful interpretation of PCT in the clinical context mandatory. This narrative review aims to update clinicians on the strengths and limitations of PCT for patient management, focusing on research conducted within the last 4 years.

Effectiveness and safety of procalcitonin evaluation for reducing mortality in adults with sepsis, severe sepsis or septic shock

BACKGROUND

Serum procalcitonin (PCT) evaluation has been proposed for early diagnosis and accurate staging and to guide decisions regarding patients with sepsis, severe sepsis and septic shock, with possible reduction in mortality.

OBJECTIVES

To assess the effectiveness and safety of serum PCT evaluation for reducing mortality and duration of antimicrobial therapy in adults with sepsis, severe sepsis or septic shock.

SEARCH METHODS

We searched the Central Register of Controlled Trials (CENTRAL; 2015, Issue 7); MEDLINE (1950 to July 2015); Embase (Ovid SP, 1980 to July 2015); Latin American Caribbean Health Sciences Literature (LILACS via BIREME, 1982 to July 2015); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; EBSCO host, 1982 to July 2015), and trial registers (ISRCTN registry, ClinicalTrials.gov and CenterWatch, to July 2015). We reran the search in October 2016. We added three studies of interest to a list of 'Studies awaiting classification' and will incorporate these into formal review findings during the review update.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) testing PCT-guided decisions in at least one of the comparison arms for adults (≥ 18 years old) with sepsis, severe sepsis or septic shock, according to international definitions and irrespective of the setting.

DATA COLLECTION AND ANALYSIS

Two review authors extracted study data and assessed the methodological quality of included studies. We conducted meta-analysis with random-effects models for the following primary outcomes: mortality and time spent receiving antimicrobial therapy in hospital and in the intensive care unit (ICU), as well as time spent on mechanical ventilation and change in antimicrobial regimen from a broad to a narrower spectrum.

MAIN RESULTS

We included 10 trials with 1215 participants. Low-quality evidence showed no significant differences in mortality at longest follow-up (risk ratio (RR) 0.81, 95% confidence interval (CI) 0.65 to 1.01; I2 = 10%; 10 trials; N = 1156), at 28 days (RR 0.89, 95% CI 0.61 to 1.31; I2 = 0%; four trials; N = 316), at ICU discharge (RR 1.03, 95% CI 0.50 to 2.11; I2 = 49%; three trials; N = 506) and at hospital discharge (RR 0.98, 95% CI 0.75 to 1.27; I2 = 0%; seven trials; N = 805; moderate-quality evidence). However, mean time receiving antimicrobial therapy in the intervention groups was -1.28 days (95% CI to -1.95 to -0.61; I2 = 86%; four trials; N = 313; very low-quality evidence). No primary study has analysed the change in antimicrobial regimen from a broad to a narrower spectrum.

AUTHORS' CONCLUSIONS

Up-to-date evidence of very low to moderate quality, with insufficient sample power per outcome, does not clearly support the use of procalcitonin-guided antimicrobial therapy to minimize mortality, mechanical ventilation, clinical severity, reinfection or duration of antimicrobial therapy of patients with septic conditions.

Ventilator-Associated Pneumonia and Other Complications

Ventilator-associated pneumonia occurs in patients who have been intubated for two to three days with significant exposure to hospital-acquired organisms. Treatment should be initiated rapidly and cover P. aeruginosa, Escheriochia coli, Klebsiella pneumonia, and Acinetobacter species as well as methicillin-resistant S. aureus. Within 72 h or with the availability of culture results, antibiotics should be narrowed. Active research is on-going to identify patients at risk for ventilator-associated complications and to minimize the likelihood of infection in these patients.

Sepsis and Septic Shock: Lingering Questions

Sepsis and septic shock are major health conditions in the United States, with a high incidence and mortality. The Surviving Sepsis Campaign, which was formed in 2002, formulates guidelines for the management of severe sepsis and septic shock and has actually demonstrated a reduction in mortality with institution of "sepsis bundles." Despite this, some elements of the guidelines have been questioned, and recent data suggest that strict compliance with bundles and protocols may not be necessary. Still, prompt recognition and treatment of sepsis and septic shock remain of utmost importance.

Using Procalcitonin to Guide Antibiotic Therapy

Procalcitonin levels rise in response to systemic inflammation, especially of bacterial origin. Multiple randomized controlled trials have demonstrated that procalcitonin-based algorithms can safely reduce antibiotic use in 2 clinical scenarios. First, in stable, low-risk patients with respiratory infections, procalcitonin levels of <0.25 µg/L can guide the decision to withhold antibiotics or stop therapy early. Second, in critically ill patients with suspected sepsis, clinicians should not initially withhold antibiotics, but procalcitonin levels of <0.5 µg/L or levels that decrease by ≥80% from peak can guide discontinuation once patients stabilize. The recent stop antibiotics on procalcitonin guidance study (SAPS), the largest procalcitonin trial to date, demonstrated reduction in both antibiotic exposure and mortality in critically ill patients. Although procalcitonin is ready for routine use, future research should examine optimal strategies for implementation in hospitals, its real-world impact on clinical outcomes and costs, its applicability to immunocompromised patients, and the generalizability of trials to the US population.

Significance of soluble triggering receptor expressed on myeloid cells-1 elevation in patients admitted to the intensive care unit with sepsis

Background

Among septic patients admitted to the intensive care unit (ICU), early recognition of those with the highest risk of death is of paramount importance. Since clinical judgment is sometimes uncertain biomarkers could provide additional information likely to guide critical illness management. We evaluated the prognostic value of soluble Triggering Receptor Expressed by Myeloid cells 1 (sTREM-1), procalcitonin (PCT) and leucocyte surface expression of CD64.

Methods

This was a prospective cohort study, which included 190 septic patient admitted to the ICU in two hospitals. Blood samples for biomarker measurements were obtained upon admission and thereafter. The Simplified Acute Physiology Score (SAPS) II and the Sequential Organ Failure Assessment (SOFA) score were calculated. The primary outcome was all-cause death in the ICU.

Results

The mortality rate reached 25.8 %. The best predictive value of the three biomarkers was obtained with baseline sTREM-1, although clinical scores outperformed this. Accuracy was greater in patients without prior exposure to antibiotics and in those with proven bacterial infection. Adding sTREM-1 levels to SAPS II increased its specificity to 98 %. The soluble TREM-1 level, core temperature and SAPS II value were the only independent predictors of death after adjustment for potential confounders. A decrease in sTREM-1 with time was also more pronounced in survivors than in non-survivors.

Conclusions

sTREM-1 was found to be the best prognostic biomarker among those tested. Both baseline values and variations with time seemed relevant. Although SAPS II outperformed sTREM-1 regarding the prediction of ICU survival, the biomarker could provide additional information.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1893-4) contains supplementary material, which is available to authorized users.

Emerging infection and sepsis biomarkers: will they change current therapies?

INTRODUCTION

Sepsis is a heterogeneous syndrome characterized by both immune hyperactivity and relative immune suppression. Biomarkers have the potential to improve recognition and management of sepsis through three main applications: diagnosis, monitoring response to treatment, and stratifying patients based on prognosis or underlying biological response.

AREAS COVERED

This review focuses on specific examples of well-studied, evidence-supported biomarkers, and discusses their role in clinical practice with special attention to antibiotic stewardship and cost-effectiveness. Biomarkers were selected based on availability of robust prospective trials and meta-analyses which supported their role as emerging tools to improve the clinical management of sepsis. Expert commentary: Great strides have been made in candidate sepsis biomarker discovery and testing, with the biomarkers in this review showing promise. Yet sepsis remains a dynamic illness with a great degree of biological heterogeneity - heterogeneity which may be further resolved by recently discovered gene expression-based endotypes in septic shock.

AME evidence series 001-The Society for Translational Medicine: clinical practice guidelines for diagnosis and early identification of sepsis in the hospital

Sepsis is a heterogeneous disease caused by an infection stimulus that triggers several complex local and systemic immuno-inflammatory reactions, which results in multiple organ dysfunction and significant morbidity and mortality. The diagnosis of sepsis is challenging because there is no gold standard for diagnosis. As a result, the clinical diagnosis of sepsis is ever changing to meet the clinical and research requirements. Moreover, although there are many novel biomarkers and screening tools for predicting the risk of sepsis, the diagnostic performance and effectiveness of these measures are less than satisfactory, and there is insufficient evidence to recommend clinical use of these new techniques. As a consequence, diagnostic criteria for sepsis need regular revision to cope with emerging evidence. This review aims to present the most updated information on diagnosis and early recognition of sepsis. Recommendations for clinical use of different diagnostic tools rely on the Grades of Recommendation Assessment, Development and Evaluation (GRADE) framework. Because most of the studies were observational and did not allow a reliable assessment of these tools, a two-step inference approach was employed. Future trials need to confirm or refute a particular index test and should directly explore relevant patient outcome parameters.

Effect of Procalcitonin Testing on Health-care Utilization and Costs in Critically Ill Patients in the United States

BACKGROUND

There is a growing use of procalcitonin (PCT) to facilitate the diagnosis and management of severe sepsis. We investigated the impact of one to two PCT determinations on ICU day 1 on health-care utilization and cost in a large research database.

METHODS

A retrospective, propensity score-matched multivariable analysis was performed on the Premier Healthcare Database for patients admitted to the ICU with one to two PCT evaluations on day 1 of ICU admission vs patients who did not have PCT testing.

RESULTS

A total of 33,569 PCT-managed patients were compared with 98,543 propensity score-matched non-PCT patients. In multivariable regression analysis, PCT utilization was associated with significantly decreased total length of stay (11.6 days [95% CI, 11.4 to 11.7] vs 12.7 days [95% CI, 12.6 to 12.8]; 95% CI for difference, 1 to 1.3; P < .001) and ICU length of stay (5.1 days [95% CI, 5.1 to 5.2] vs 5.3 days [95% CI, 5.3 to 5.4]; 95% CI for difference, 0.1 to 0.3; P < .03), and lower hospital costs ($30,454 [95% CI, 29,968 to 31,033] vs $33,213 [95% CI, 32,964 to 33,556); 95% CI for difference, 2,159 to 3,321; P < .001). There was significantly less total antibiotic exposure (16.2 days [95% CI, 16.1 to 16.5] vs 16.9 days [95% CI, 16.8 to 17.1]; 95% CI for difference, -0.9 to 0.4; P = .006) in PCT-managed patients. Patients in the PCT group were more likely to be discharged to home (44.1% [95% CI, 43.7 to 44.6] vs 41.3% [95% CI, 41 to 41.6]; 95% CI for difference, 2.3 to 3.3; P = .006). Mortality was not different in an analysis including the 96% of patients who had an independent measure of mortality risk available (19.1% [95% CI, 18.7 to 19.4] vs 19.1% [95% CI, 18.9 to 19.3]; 95% CI for difference, -0.5 to 0.4; P = .93).

CONCLUSIONS

Use of PCT testing on the first day of ICU admission was associated with significantly lower hospital and ICU lengths of stay, as well as decreased total, ICU, and pharmacy cost of care. Further elucidation of clinical outcomes requires additional data.

Delta Procalcitonin Is a Better Indicator of Infection Than Absolute Procalcitonin Values in Critically Ill Patients: A Prospective Observational Study

Purpose. To investigate whether absolute value of procalcitonin (PCT) or the change (delta-PCT) is better indicator of infection in intensive care patients. Materials and Methods. Post hoc analysis of a prospective observational study. Patients with suspected new-onset infection were included in whom PCT, C-reactive protein (CRP), temperature, and leukocyte (WBC) values were measured on inclusion (t₀) and data were also available from the previous day (t₋₁). Based on clinical and microbiological data, patients were grouped post hoc into infection- (I-) and noninfection- (NI-) groups. Results. Of the 114 patients, 85 (75%) had proven infection. PCT levels were similar at t₋₁: I-group (median [interquartile range]): 1.04 [0.40–3.57] versus NI-group: 0.53 [0.16–1.68], p = 0.444. By t₀ PCT levels were significantly higher in the I-group: 4.62 [1.91–12.62] versus 1.12 [0.30–1.66], p = 0.018. The area under the curve to predict infection for absolute values of PCT was 0.64 [95% CI = 0.52–0.76], p = 0.022; for percentage change: 0.77 [0.66–0.87], p < 0.001; and for delta-PCT: 0.85 [0.78–0.92], p < 0.001. The optimal cut-off value for delta-PCT to indicate infection was 0.76 ng/mL (sensitivity 80 [70–88]%, specificity 86 [68-96]%). Neither absolute values nor changes in CRP, temperature, or WBC could predict infection. Conclusions. Our results suggest that delta-PCT values are superior to absolute values in indicating infection in intensive care patients. This trial is registered with ClinicalTrials.gov identifier: NCT02311816.

Advances in antibiotic therapy in the critically ill

Infections occur frequently in critically ill patients and their management can be challenging for various reasons, including delayed diagnosis, difficulties identifying causative microorganisms, and the high prevalence of antibiotic-resistant strains. In this review, we briefly discuss the importance of early infection diagnosis, before considering in more detail some of the key issues related to antibiotic management in these patients, including controversies surrounding use of combination or monotherapy, duration of therapy, and de-escalation. Antibiotic pharmacodynamics and pharmacokinetics, notably volumes of distribution and clearance, can be altered by critical illness and can influence dosing regimens. Dosing decisions in different subgroups of patients, e.g., the obese, are also covered. We also briefly consider ventilator-associated pneumonia and the role of inhaled antibiotics. Finally, we mention antibiotics that are currently being developed and show promise for the future.

Procalcitonin: Is This the Promised Biomarker for Critically Ill Patients?

Objective Procalcitonin (PCT) has been increasingly used in the critical care setting to determine the presence of bacterial infection and also to guide antibiotic therapy. We reviewed PCT's physiologic role, as well as its clinical utility for the management of pediatric critically ill patients. Findings PCT is a precursor of the hormone calcitonin. Its production is induced by inflammatory conditions, especially bacterial infections. Literature shows that PCT is a moderately reliable diagnostic test for severe bacterial infection in children. Synthesis of available adult studies suggests that the use of PCT-based algorithms to support medical decision making reduces antibiotic exposure without compromising safety in critically ill patients. However, no study has addressed the usefulness and safety of PCT to guide antibiotic therapy in severely ill children. In pediatric patients with acute lower respiratory tract infections, the use of PCT-based algorithms also led to a safe decrease in antibiotic treatment duration. Conclusion PCT has demonstrated clinical utility in the pediatric critical care setting when used for the diagnosis of bacterial infections and to guide antibiotic use in children with acute lower respiratory tract infections. However, more research is needed in critically ill children to determine the utility of PCT-driven antibiotic therapy in this population.

Severe sepsis in older adults

Severe sepsis may be underrecognized in older adults. Therefore, the purpose of this article is to review special considerations related to early detection of severe sepsis in older adults. Normal organ changes attributed to aging may delay early detection of sepsis at the time when interventions have the greatest potential to improve patient outcomes. Systems are reviewed for changes. For example, the cardiovascular system may have a limited or absent compensatory response to inflammation after an infectious insult, and the febrile response and recruitment of white blood cells may be blunted because of immunosenescence in aging. Three of the 4 hallmark responses (temperature, heart rate, and white blood cell count) to systemic inflammation may be diminished in older adults as compared with younger adults. It is important to consider that older adults may not always manifest the typical systemic inflammatory response syndrome. Atypical signs such as confusion, decreased appetite, and unsteady gait may occur before sepsis related organ failure. Systemic inflammatory response syndrome criteria and a comparison of organ failure criteria were reviewed. Mortality rates in sepsis and severe sepsis remain high and are often complicated by multiple organ failures. As the numbers of older adults increase, early identification and prompt treatment is crucial in improving patient outcomes.

Efficacy and safety of procalcitonin guidance in reducing the duration of antibiotic treatment in critically ill patients: a randomised, controlled, open-label trial

BACKGROUND

In critically ill patients, antibiotic therapy is of great importance but long duration of treatment is associated with the development of antimicrobial resistance. Procalcitonin is a marker used to guide antibacterial therapy and reduce its duration, but data about safety of this reduction are scarce. We assessed the efficacy and safety of procalcitonin-guided antibiotic treatment in patients in intensive care units (ICUs) in a health-care system with a comparatively low use of antibiotics.

METHODS

We did a prospective, multicentre, randomised, controlled, open-label intervention trial in 15 hospitals in the Netherlands. Critically ill patients aged at least 18 years, admitted to the ICU, and who received their first dose of antibiotics no longer than 24 h before inclusion in the study for an assumed or proven infection were eligible to participate. Patients who received antibiotics for presumed infection were randomly assigned (1:1), using a computer-generated list, and stratified (according to treatment centre, whether infection was acquired before or during ICU stay, and dependent on severity of infection [ie, sepsis, severe sepsis, or septic shock]) to receive either procalcitonin-guided or standard-of-care antibiotic discontinuation. Both patients and investigators were aware of group assignment. In the procalcitonin-guided group, a non-binding advice to discontinue antibiotics was provided if procalcitonin concentration had decreased by 80% or more of its peak value or to 0·5 μg/L or lower. In the standard-of-care group, patients were treated according to local antibiotic protocols. Primary endpoints were antibiotic daily defined doses and duration of antibiotic treatment. All analyses were done by intention to treat. Mortality analyses were completed for all patients (intention to treat) and for patients in whom antibiotics were stopped while being on the ICU (per-protocol analysis). Safety endpoints were reinstitution of antibiotics and recurrent inflammation measured by C-reactive protein concentrations and they were measured in the population adhering to the stopping rules (per-protocol analysis). The study is registered with ClinicalTrials.gov, number NCT01139489, and was completed in August, 2014.

FINDINGS

Between Sept 18, 2009, and July 1, 2013, 1575 of the 4507 patients assessed for eligibility were randomly assigned to the procalcitonin-guided group (761) or to standard-of-care (785). In 538 patients (71%) in the procalcitonin-guided group antibiotics were discontinued in the ICU. Median consumption of antibiotics was 7·5 daily defined doses (IQR 4·0-12·7) in the procalcitonin-guided group versus 9·3 daily defined doses (5·0-16·6) in the standard-of-care group (between-group absolute difference 2·69, 95% CI 1·26-4·12, p<0·0001). Median duration of treatment was 5 days (3-9) in the procalcitonin-guided group and 7 days (4-11) in the standard-of-care group (between-group absolute difference 1·22, 0·65-1·78, p<0·0001). Mortality at 28 days was 149 (20%) of 761 patients in the procalcitonin-guided group and 196 (25%) of 785 patients in the standard-of-care group (between-group absolute difference 5·4%, 95% CI 1·2-9·5, p=0·0122) according to the intention-to-treat analysis, and 107 (20%) of 538 patients in the procalcitonin-guided group versus 121 (27%) of 457 patients in the standard-of-care group (between-group absolute difference 6·6%, 1·3-11·9, p=0·0154) in the per-protocol analysis. 1-year mortality in the per-protocol analysis was 191 (36%) of 538 patients in the procalcitonin-guided and 196 (43%) of 457 patients in the standard-of-care groups (between-group absolute difference 7·4, 1·3-13·8, p=0·0188).

INTERPRETATION

Procalcitonin guidance stimulates reduction of duration of treatment and daily defined doses in critically ill patients with a presumed bacterial infection. This reduction was associated with a significant decrease in mortality. Procalcitonin concentrations might help physicians in deciding whether or not the presumed infection is truly bacterial, leading to more adequate diagnosis and treatment, the cornerstones of antibiotic stewardship.

FUNDING

Thermo Fisher Scientific.

Procalcitonin concentrations as a predictor of unexpected readmission and mortality after intensive care unit discharge: A retrospective cohort study

Procalcitonin (PCT) has been used to guide treatment in critically ill patients with sepsis, but whether PCT at intensive care unit (ICU) discharge can stratify risks of post-ICU readmission or mortality is unknown. This cohort study compared the ability of PCT with C-reactive protein (CRP) in predicting unexpected adverse post-ICU events. Of the 1877 patients admitted to the multidisciplinary ICU between 1 April 2012 and 31 March 2014, 1653 (88.1%) were discharged without treatment limitations. A total of 71 (4.3%) were readmitted and 18 patients (1%) died unexpectedly after ICU discharge during the same hospitalization. Both PCT (0.6 vs 0.4 μg/L, P = .002) and a high CRP concentration >100 mg/L (58% vs 41%, P = .004) at ICU discharge were associated with an increased risk of adverse post-ICU events in the univariate analyses; however, the ability of PCT to discriminate between patients with and without adverse post-ICU outcomes was limited (area under the receiver operating characteristic curve = 0.61; 95% confidence interval, 0.55-0.66). In the multivariable analysis, only a high CRP concentration (odds ratio, 1.92; 95% confidence interval, 1.12-3.11; P = .008) was associated with an increased adverse post-ICU events. Elevated PCT concentration at ICU discharge was inadequate in its predictive ability to guide ICU discharge.

Which patients with ARDS benefit from lung biopsy?

A central tenet of caring for patients with ARDS is to treat the underlying cause, be it sepsis, pneumonia, or removal of an offending toxin. Identifying the risk factor for ARDS has even been proposed as essential to diagnosing ARDS. Not infrequently, however, the precipitant for acute hypoxemic respiratory failure is unclear, and this raises the question of whether a histologic lung diagnosis would benefit the patient. In this review, we consider the historic role of pathology in establishing a diagnosis of ARDS and the published experience of surgical and transbronchial lung biopsy in patients with ARDS. We reflect on which pathologic diagnoses influence treatment and suggest a patient-centric approach to weigh the risks and benefits of a lung biopsy for critically ill patients who may have ARDS.

Procalcitonin-based algorithms to initiate or stop antibiotic therapy in critically ill patients: Is it time to rethink our strategy?

Procalcitonin (PCT)-based antibiotic management algorithms for critically ill patients have been described in the literature. An evaluation of the available evidence demonstrates that studies have utilised PCT in various clinical scenarios: for the initiation of antimicrobials; for cessation or de-escalation of antimicrobials; or for the combination of both strategies. Current PCT reviews and meta-analyses have combined studies from all different clinical scenarios. However, there may be significant variations in algorithm compliance and clinical outcomes associated with the use of PCT in these different strategies. As such, the current review focused on separating out the studies utilising PCT in the critically ill population for different treatment strategies. Based on this review, we would recommend that PCT should not be used as the sole deciding factor for the initiation of antimicrobials. As such, PCT should not be obtained in patients who do not exhibit evidence of infection. In patients who do have signs of infection and antimicrobials have been initiated, a strategy that utilises PCT for the discontinuation or de-escalation of antimicrobials is likely to decrease the duration of treatment without adversely affecting outcome.

Biomarkers of Endothelial Activation Are Associated with Poor Outcome in Critical Illness

Background

Endothelial activation plays a role in organ dysfunction in the systemic inflammatory response syndrome (SIRS). Angiopoietin-1 (Ang-1) promotes vascular quiescence while angiopoietin-2 (Ang-2) mediates microvascular leak. Circulating levels of Ang-1 and Ang-2 in patients with SIRS could provide insight on risks for organ dysfunction and death distinct from inflammatory proteins. In this study, we determined if biomarkers of endothelial activation and inflammation exhibit independent associations with poor outcomes in SIRS.

Methods

We studied 943 critically ill patients with SIRS admitted to an Intensive Care Unit (ICU) of an academic medical center. We measured plasma levels of endothelial markers (Ang-1, Ang-2, soluble vascular cell adhesion molecule-1 (sVCAM-1)) and inflammatory markers (interleukin-6 (IL-6), interleukin-8 (IL-8), granulocyte-colony stimulating factor (G-CSF), soluble tumor necrosis factor receptor-1 (sTNFR-1)) within 24 hours of enrollment. We tested for associations between each marker and 28 day mortality, shock, and day 3 sequential organ failure assessment (SOFA) score. For 28 day mortality, we performed sensitivity analysis for those subjects with sepsis and those with sterile inflammation. We used multivariate models to adjust for clinical covariates and determine if associations identified with endothelial activation markers were independent of those observed with inflammatory markers.

Results

Higher levels of all biomarkers were associated with increased 28 day mortality except levels of Ang-1 which were associated with lower mortality. After adjustment for comorbidities and sTNFR-1 concentration, a doubling of Ang-1 concentration was associated with lower 28 day mortality (Odds ratio (OR) = 0.81; p<0.01), shock (OR = 0.82; p<0.001), and SOFA score (β = -0.50; p<0.001), while Ang-2 concentration was associated with increased mortality (OR = 1.55; p<0.001), shock (OR = 1.51; p<0.001), and SOFA score (β = +0.63; p<0.001). sVCAM-1 was not independently associated with SIRS outcomes.

Conclusions

In critically ill patients with SIRS, early measurements of Ang-1 and Ang-2 are associated with death and organ dysfunction independently of simultaneously-measured markers of inflammation.

Pros and cons of using biomarkers versus clinical decisions in start and stop decisions for antibiotics in the critical care setting

INTRODUCTION

Patients in the intensive care unit (ICU) frequently receive prolonged or even unnecessary antibiotic therapy, which selects for antibiotic-resistant bacteria. Over the last decade there has been great interest in biomarkers, particularly procalcitonin, to reduce antibiotic exposure.

METHODS

In this narrative review, we discuss the value of biomarkers and provide additional information beyond clinical evaluation in order to be clinically useful and review the literature on sepsis biomarkers outside the neonatal period. Both benefits and limitations of biomarkers for clinical decision-making are reviewed.

RESULTS

Several randomized controlled trials (RCTs) have shown the safety and efficacy of procalcitonin to discontinue antibiotic therapy in patients with severe sepsis or septic shock. In contrast, there is limited utility of procalcitonin for treatment initiation or withholding therapy initially. In addition, an algorithm using procalcitonin for treatment escalation has been ineffective and is probably associated with poorer outcomes. Little data from interventional studies are available for other biomarkers for antibiotic stewardship, except for C-reactive protein (CRP), which was recently found to be similarly effective and safe as procalcitonin in a randomized controlled trial. We finally briefly discuss biomarker-unrelated approaches to reduce antibiotic duration in the ICU, which have shown that even without biomarker guidance, most patients with sepsis can be treated with relatively short antibiotic courses of approximately 7 days.

CONCLUSIONS

In summary, there is an ongoing unmet need for biomarkers which can reliably and early on identify patients who require antibiotic therapy, distinguish between responders and non-responders and help to optimize antibiotic treatment decisions among critically ill patients. Available evidence needs to be better incorporated in clinical decision-making.

Procalcitonin-guided antibiotic therapy for septic patients in the surgical intensive care unit

In critically ill patients, elucidating those patients with the systemic inflammatory response syndrome (SIRS) from an infectious source (sepsis), versus those who have SIRS without infection, can be challenging since the clinical features are the same.

Even with strict monitoring and testing, 39–98 % of patients with SIRS will never have bacteriological confirmation of an infection, and 6–17 % of patients with a documented infection will not show signs of SIRS. Due to this overlap, an extensive amount of research has been performed to investigate ways of determining and separating SIRS from infection, compared to SIRS due to trauma, surgical stress, or other non-infectious causes. This review article will discuss the recommended and peer-approved use of procalcitonin in septic patients in the intensive care unit and its use as a guide to antibiotic initiation and termination. The article will focus on the prospective randomized trials (Level 1 evidence) that have been conducted, and lesser levels of evidence will be referenced as needed to substantiate a conclusion.

The literature documents multiple benefits of using procalcitonin as a guide to cost savings and appropriate termination of antibiotics by its use as a new objective marker of bacteremia that was previously not available. This article will show that antibiotics should be terminated when the procalcitonin level falls below 0.5 ng/mL.

Ventilator associated pneumonia in the ICU: where has it gone?

PURPOSE OF REVIEW

To highlight the clinical importance of ventilator-associated pneumonia (VAP) in an era of escalating antimicrobial resistance.

RECENT FINDINGS

VAP continues to be an important infection in the critically ill. The development of rapid microbiologic diagnostics and new antimicrobial agents offer opportunities for improved treatment strategies for VAP balancing the need to treat effectively in a timely manner and antimicrobial stewardship. Additionally, the new surveillance definitions for assessing the quality of care in critically ill patients (ventilator-associated events, ventilator-associated conditions, and infection-related ventilator-associated conditions) do not appear to be adequate surrogates for the identification of VAP.

SUMMARY

Clinicians caring for critically ill patients should be aware of the importance of correctly treating VAP. As new diagnostic technologies and antimicrobials become available for VAP, their incorporation into routine patient management should occur in a way that optimizes patient outcomes wherein minimizing further emergence of antimicrobial resistance.

Human Neutrophil Lipocalin as a Superior Diagnostic Means To Distinguish between Acute Bacterial and Viral Infections

The distinction between causes of acute infections is a major clinical challenge. Current biomarkers, however, are not sufficiently accurate. Human neutrophil lipocalin (HNL) concentrations in serum or whole blood activated by formyl-methionine-leucine-phenylalanine (fMLP) were shown to distinguish acute infections of bacterial or viral cause with high accuracy. The aim was therefore to compare the clinical performance of HNL with currently used biomarkers. Seven hundred twenty-five subjects (144 healthy controls and 581 patients with signs and symptoms of acute infections) were included in the study. C-reactive protein (CRP), the expression of CD64 on neutrophils, procalcitonin (PCT), and blood neutrophil counts were measured by established techniques, and HNL concentrations were measured in whole-blood samples after activation with fMLP. All tested biomarkers were elevated in bacterial as opposed to viral infections (P < 0.001). CRP, PCT, and CD64 expression in neutrophils was elevated in viral infections compared to healthy controls (P < 0.001). In the distinction between healthy controls and patients with bacterial infections, the areas under the receiver operating characteristic (ROC) curves were >0.85 for all biomarkers, whereas for the distinction between bacterial and viral infections, only HNL concentration in fMLP-activated whole blood showed an area under the ROC curve (AUROC) of >0.90 and superior clinical performance. The clinical performance of HNL in fMLP-activated whole blood was superior to current biomarkers and similar to previous results of HNL in serum. The procedure can be adopted for point-of-care testing with response times of <15 min.

Antibiotic use in US hospitals: quantification, quality measures and stewardship

A majority of patients hospitalized in the US hospitals receive an antibiotic during their hospitalization. Furthermore, up to half of antibiotics prescribed in hospitals are inappropriate. In the setting of continued emergence of antibiotic-resistant pathogens and a limited pipeline of new antimicrobials, attention to optimizing antibiotic use in healthcare settings is essential. We review the measures of antibiotic consumption in the USA, the evolving metrics for comparing antibiotic use (known as benchmarking), trends in antibiotic use, the structure and outcome measures of Antimicrobial Stewardship Programs and interventions to optimize antimicrobial use.

Procalcitonin-Guided Antibiotic Therapy Duration in Critically Ill Adults

Procalcitonin is a promising biomarker for antibiotic therapy because its levels rise and fall quickly with bacterial infections. A multi-database literature search was reviewed with 3 primary prospective randomized control trials used in further analysis. The results indicated that a procalcitonin-guided antibiotic protocol reduces the number of days a patient has to take antibiotics while having no effect on mortality when compared with control groups. Short-term studies did not show a difference in the intensive care unit length of stay, infection relapse rate, super-infection rate, or multidrug-resistant bacteria rate between the procalcitonin-protocol and control group. Because procalcitonin-guided antibiotic therapy has been shown to reduce the duration of treatment with antibiotics in critically ill patients without worsening the mortality rate or other outcomes, the implementation of a procalcitonin-guided antibiotic therapy should be considered for patients with proven or highly suspected bacterial infections in the intensive care unit.

Comparing the prognostic performance of ASSIST to interleukin-6 and procalcitonin in patients with severe sepsis or septic shock

CONTEXT

We recently derived and validated a multi-biomarker-based model (ASSIST) to stratify patients with sepsis based on initial mortality risk.

OBJECTIVE

The objective of this study was to compare the performance of ASSIST to interleukin-6 (IL6) and procalcitonin (PCT).

METHODS

The area-under-the-receiver operating characteristic curve for predicting 28-d mortality using ASSIST was compared with that of IL6 (n = 452) and PCT (n = 235).

RESULTS

The area under the curve for ASSIST was greater than that of IL6 and PCT.

CONCLUSIONS

ASSIST estimated the probability of mortality more reliably than IL6 and PCT in this cohort of patients with sepsis.

Interventions to improve antibiotic prescribing practices for hospital inpatients

BACKGROUND

The first publication of this review in Issue 3, 2005 included studies up to November 2003. This update adds studies to December 2006 and focuses on application of a new method for meta-analysis of interrupted time series studies and application of new Cochrane Effective Practice and Organisation of Care (EPOC) Risk of Bias criteria to all studies in the review, including those studies in the previously published version. The aim of the review is to evaluate the impact of interventions from the perspective of antibiotic stewardship. The two objectives of antibiotic stewardship are first to ensure effective treatment for patients with bacterial infection and second support professionals and patients to reduce unnecessary use and minimize collateral damage.

OBJECTIVES

To estimate the effectiveness of professional interventions that, alone or in combination, are effective in antibiotic stewardship for hospital inpatients, to evaluate the impact of these interventions on reducing the incidence of antimicrobial-resistant pathogens or Clostridium difficile infection and their impact on clinical outcome.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE from 1980 to December 2006 and the EPOC specialized register in July 2007 and February 2009 and bibliographies of retrieved articles. The main comparison is between interventions that had a restrictive element and those that were purely persuasive. Restrictive interventions were implemented through restriction of the freedom of prescribers to select some antibiotics. Persuasive interventions used one or more of the following methods for changing professional behaviour: dissemination of educational resources, reminders, audit and feedback, or educational outreach. Restrictive interventions could contain persuasive elements.

SELECTION CRITERIA

We included randomized clinical trials (RCTs), controlled clinical trials (CCT), controlled before-after (CBA) and interrupted time series studies (ITS). Interventions included any professional or structural interventions as defined by EPOC. The intervention had to include a component that aimed to improve antibiotic prescribing to hospital inpatients, either by increasing effective treatment or by reducing unnecessary treatment. The results had to include interpretable data about the effect of the intervention on antibiotic prescribing or microbial outcomes or relevant clinical outcomes.

DATA COLLECTION AND ANALYSIS

Two authors extracted data and assessed quality. We performed meta-regression of ITS studies to compare the results of persuasive and restrictive interventions. Persuasive interventions advised physicians about how to prescribe or gave them feedback about how they prescribed. Restrictive interventions put a limit on how they prescribed; for example, physicians had to have approval from an infection specialist in order to prescribe an antibiotic. We standardized the results of some ITS studies so that they are on the same scale (percent change in outcome), thereby facilitating comparisons of different interventions. To do this, we used the change in level and change in slope to estimate the effect size with increasing time after the intervention (one month, six months, one year, etc) as the percent change in level at each time point. We did not extrapolate beyond the end of data collection after the intervention. The meta-regression was performed using standard weighted linear regression with the standard errors of the coefficients adjusted where necessary.

MAIN RESULTS

For this update we included 89 studies that reported 95 interventions. Of the 89 studies, 56 were ITSs (of which 4 were controlled ITSs), 25 were RCT (of which 5 were cluster-RCTs), 5 were CBAs and 3 were CCTs (of which 1 was a cluster-CCT).Most (80/95, 84%) of the interventions targeted the antibiotic prescribed (choice of antibiotic, timing of first dose and route of administration). The remaining 15 interventions aimed to change exposure of patients to antibiotics by targeting the decision to treat or the duration of treatment. Reliable data about impact on antibiotic prescribing data were available for 76 interventions (44 persuasive, 24 restrictive and 8 structural). For the persuasive interventions, the median change in antibiotic prescribing was 42.3% for the ITSs, 31.6% for the controlled ITSs, 17.7% for the CBAs, 3.5% for the cluster-RCTs and 24.7% for the RCTs. The restrictive interventions had a median effect size of 34.7% for the ITSs, 17.1% for the CBAs and 40.5% for the RCTs. The structural interventions had a median effect of 13.3% for the RCTs and 23.6% for the cluster-RCTs. Data about impact on microbial outcomes were available for 21 interventions but only 6 of these also had reliable data about impact on antibiotic prescribing.Meta-analysis of 52 ITS studies was used to compare restrictive versus purely persuasive interventions. Restrictive interventions had significantly greater impact on prescribing outcomes at one month (32%, 95% confidence interval (CI) 2% to 61%, P = 0.03) and on microbial outcomes at 6 months (53%, 95% CI 31% to 75%, P = 0.001) but there were no significant differences at 12 or 24 months. Interventions intended to decrease excessive prescribing were associated with reduction in Clostridium difficile infections and colonization or infection with aminoglycoside- or cephalosporin-resistant gram-negative bacteria, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis. Meta-analysis of clinical outcomes showed that four interventions intended to increase effective prescribing for pneumonia were associated with significant reduction in mortality (risk ratio 0.89, 95% CI 0.82 to 0.97), whereas nine interventions intended to decrease excessive prescribing were not associated with significant increase in mortality (risk ratio 0.92, 95% CI 0.81 to 1.06).

AUTHORS' CONCLUSIONS

The results show that interventions to reduce excessive antibiotic prescribing to hospital inpatients can reduce antimicrobial resistance or hospital-acquired infections, and interventions to increase effective prescribing can improve clinical outcome. This update provides more evidence about unintended clinical consequences of interventions and about the effect of interventions to reduce exposure of patients to antibiotics. The meta-analysis supports the use of restrictive interventions when the need is urgent, but suggests that persuasive and restrictive interventions are equally effective after six months.