Impact of quantitative invasive diagnostic techniques in the management and outcome of mechanically ventilated patients with suspected pneumonia

Bronchoscopic Diagnosis of Severe Respiratory Infections

The diagnosis of severe respiratory infections in intensive care remains an area of uncertainty and involves a complex balancing of risks and benefits. Due to the frequent colonisation of the lower respiratory tract in mechanically ventilated patients, there is an ever-present possibility of microbiological samples being contaminated by bystander organisms. This, coupled with the frequency of alveolar infiltrates arising from sterile insults, risks over-treatment and antimicrobial-associated harm. The use of bronchoscopic sampling to obtain protected lower respiratory samples has long been advocated to overcome this problem. The use of bronchoscopy further enables accurate cytological assessment of the alveolar space and direct inspection of the proximal airways for signs of fungal infection or alternative pathologies. With a growing range of molecular techniques, including those based on nucleic acid amplification and even alveolar visualisation and direct bacterial detection, the potential for bronchoscopy is increasing concomitantly. Despite this, there remain concerns regarding the safety of the technique and its benefits versus less invasive sampling techniques. These discussions are reflected in the lack of consensus among international guidelines on the topic. This review will consider the benefits and challenges of diagnostic bronchoscopy in the context of severe respiratory infection.

Role of bronchoscopy in the management of patients with suspected or suffering from ventilator-associated pneumonia: A meta-analysis

Background

The utility of bronchoscopy in the treatment of patients with ventilator-associated pneumonia (VAP) has been proposed, although prior research has yielded inconclusive findings. This systematic review and meta-analysis were conducted to examine the impact of bronchoscopy on mortality rates, duration of mechanical ventilation (MV), and length of stay in the intensive care unit (ICU) among patients with VAP.

Methods

Relevant randomized controlled trials (RCTs) and cohort studies were acquired by conducting a comprehensive search in the PubMed, Embase, and Cochrane Library databases. To account for the potential heterogeneity, a random-effects model was utilized to combine the findings and incorporate its potential influence.

Results

Eight RCTs and three cohort studies, including 3907 patients with highly suspected or clinically diagnosed VAP, were included. Compared to the controls, bronchoscopy use was not associated with a significant effect on all-cause mortality (relative risk [RR]: 0.81, 95 % confidence interval [CI]: 0.62 to 1.05, p = 0.12; I2 = 57 %). Subgroup analysis showed that bronchoscopy used for the microbiological diagnosis of VAP was not associated with reduced mortality (RR: 0.92, 95 % CI: 0.75 to 1.13), while therapeutic bronchoscopy use was associated with significantly reduced mortality (RR: 0.53, 95 % CI: 0.35 to 0.81). The duration of MV or length of ICU stay was not significantly different between groups.

Conclusions

Bronchoscopy use for the purpose of the microbiological diagnosis of VAP did not reduce short-term mortality compared to diagnosis without bronchoscopy use, while therapeutic bronchoscopy use was associated with reduced mortality in these patients.

Nonbronchoscopic Bronchoalveolar Lavage Improves Respiratory Culture Accuracy in Critically Ill Patients

OBJECTIVES

Diagnosis of pneumonia is challenging in critically ill, intubated patients due to limited diagnostic modalities. Endotracheal aspirate (EA) cultures are standard of care in many ICUs; however, frequent EA contamination leads to unnecessary antibiotic use. Nonbronchoscopic bronchoalveolar lavage (NBBL) obtains sterile, alveolar cultures, avoiding contamination. However, paired NBBL and EA sampling in the setting of a lack of gold standard for airway culture is a novel approach to improve culture accuracy and limit antibiotic use in the critically ill patients.

DESIGN

We designed a pilot study to test respiratory culture accuracy between EA and NBBL. Adult, intubated patients with suspected pneumonia received concurrent EA and NBBL cultures by registered respiratory therapists. Respiratory culture microbiology, cell counts, and antibiotic prescribing practices were examined.

SETTING

We performed a prospective pilot study at the Cleveland Clinic Main Campus Medical ICU in Cleveland, Ohio for 22 months from May 2021 through March 2023.

PATIENTS OR SUBJECTS

Three hundred forty mechanically ventilated patients with suspected pneumonia were screened. Two hundred fifty-seven patients were excluded for severe hypoxia (Fio2 ≥ 80% or positive end-expiratory pressure ≥ 12 cm H2O), coagulopathy, platelets less than 50,000, hemodynamic instability as determined by the treating team, and COVID-19 infection to prevent aerosolization of the virus.

INTERVENTIONS

All 83 eligible patients were enrolled and underwent concurrent EA and NBBL.

MEASUREMENTS AND MAIN RESULTS

More EA cultures (42.17%) were positive than concurrent NBBL cultures (26.51%, p = 0.049), indicating EA contamination. The odds of EA contamination increased by eight-fold 24 hours after intubation. EA was also more likely to be contaminated with oral flora when compared with NBBL cultures. There was a trend toward decreased antibiotic use in patients with positive EA cultures if paired with a negative NBBL culture. Alveolar immune cell populations were recovered from NBBL samples, indicating successful alveolar sampling. There were no major complications from NBBL.

CONCLUSIONS

NBBL is more accurate than EA for respiratory cultures in critically ill, intubated patients. NBBL provides a safe and effective technique to sample the alveolar space for both clinical and research purposes.

Clinical, Microbiological and Treatment Characteristics of Severe Postoperative Respiratory Infections: An Observational Cohort Study

Respiratory infections are frequent and life-threatening complications of surgery. This study aimed to evaluate the clinical, microbiological and treatment characteristics of severe postoperative pneumonia (POP) and tracheobronchitis (POT) in a large series of patients. This single-center, prospective observational cohort study included patients with POP or POT requiring intensive care unit admission in the past 10 years. We recorded demographic, clinical, microbiological and therapeutic data. A total of 207 patients were included, and 152 (73%) were men. The mean (SD) age was 70 (13) years and the mean (SD) ARISCAT score was 46 (19). Ventilator-associated pneumonia was reported in 21 patients (10%), hospital-acquired pneumonia was reported in 132 (64%) and tracheobronchitis was reported in 54 (26%). The mean (SD) number of days from surgery to POP/POT diagnosis was 6 (4). The mean (SD) SOFA score was 5 (3). Respiratory microbiological sampling was performed in 201 patients (97%). A total of 177 organisms were cultured in 130 (63%) patients, with a high proportion of Gram-negative and multi-drug resistant (MDR) bacteria (20%). The most common empirical antibiotic therapy was a triple-drug regimen covering MDR Gram-negative bacteria and MRSA. In conclusion, surgical patients are a high-risk population with a high proportion of early onset severe POP/POT and nosocomial bacteria isolation.

Classical and Molecular Techniques to Diagnose HAP/VAP

Nosocomial pneumonia, including hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), are the most common nosocomial infections occurring in critically ill patients requiring intensive care. However, challenges exist in making a timely and accurate diagnosis of HAP and VAP. Under diagnosis of HAP and VAP can result in greater mortality risk, especially if accompanied by delays in the administration of appropriate antimicrobial treatment. Over diagnosis of HAP and VAP results in the unnecessary administration of broad spectrum antibiotics that can lead to further escalation of antibiotic resistance. Optimal diagnosis and management of HAP and VAP require a systematic approach that combines clinical and radiographic assessments along with proper microbiologic techniques. The use of more invasive sampling methods (bronchoalveolar lavage and protected specimen brush) may enhance specimen collection resulting in more specific diagnoses to limit unnecessary antibiotic exposure. Molecular techniques, currently in use and investigational technique, may improve the diagnosis of HAP and VAP by allowing more rapid identification of offending pathogens, if present, thus increasing both appropriate antibiotic treatment and avoiding unnecessary drug exposure.

Risk Factors and Algorithms for the Empirical Treatment of Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) continue to be major concerns for morbidity and mortality, especially in patients treated in the intensive care unit. With the rise in multidrug-resistant organisms, HAP and VAP treatment is challenged by the need for early appropriate treatment, with broad-spectrum agents, while still being aware of the principles of antibiotic stewardship. The two major society guidelines proposed a series of risk factors in their most recent guidelines to help identify patients who can most benefit from narrow- or broad-spectrum initial empiric antibiotic therapy. The guidelines reveal differences in the proposed risk factors and treatment approaches, as well as major similarities.

Compared the Microbiota Profiles between Samples from Bronchoalveolar Lavage and Endotracheal Aspirates in Severe Pneumonia: A Real-World Experience

Lower respiratory tract sampling from endotracheal aspirate (EA) and bronchoalveolar lavage (BAL) are both common methods to identify pathogens in severe pneumonia. However, the difference between these two methods in microbiota profiles remains unclear. We compared the microbiota profiles of pairwise EA and BAL samples in ICU patients with respiratory failure due to severe pneumonia. We prospectively enrolled 50 ICU patients with new onset of pneumonia requiring mechanical ventilation. EA and BAL were performed on the first ICU day, and samples were analyzed for microbial community composition via 16S rRNA metagenomic sequencing. Pathogens were identified in culture medium from BAL samples in 21 (42%) out of 50 patients. No difference was observed in the antibiotic prescription pattern, ICU mortality, or hospital mortality between BAL-positive and BAL-negative patients. The microbiota profiles in the EA and BAL samples are similar with respect to diversity, microbial composition, and microbial community correlations. The antibiotic treatment regimen was rarely changed based on the BAL findings. The samples from BAL did not provide more information than EA in the microbiota profiles. We suggest that EA is more useful than BAL for microbiome identification in mechanically ventilated patients.

Clinical Value of Bronchoscopy in Acute Respiratory Failure

Bronchoscopy may be considered the “added value” in the diagnostic and therapeutic pathway of different clinical scenarios occurring in acute respiratory critically ill patients. Rigid bronchoscopy is mainly employed in emergent clinical situations due to central airways obstruction, haemoptysis, and inhaled foreign body. Flexible bronchoscopy (FBO) has larger fields of acute applications. In intensive care settings, FBO is useful to facilitate intubation in difficult airways, guide percutaneous dilatational tracheostomy, and mucous plugs causing lobar/lung atelectasis. FBO plays a central diagnostic role in acute respiratory failure caused by intra-thoracic tumors, interstitial lung diseases, and suspected severe pneumonia. “Bronchoscopic” sampling has to be considered when “non-invasive” techniques are not diagnostic in suspected ventilator-associated pneumonia and in non-ventilated immunosuppressed patients. The combined use of either noninvasive ventilation (NIV) or High-flow nasal cannula (HFNC) with bronchoscopy is useful in different scenarios; the largest body of proven successful evidence has been found for NIV-supported diagnostic FBO in non-ventilated high risk patients to prevent and avoid intubation. The expected diagnostic/therapeutic goals of acute bronchoscopy should be balanced against the potential severe risks (i.e., cardio-pulmonary complications, bleeding, and pneumothorax). Expertise of the team is fundamental to achieve the best rate of success with the lowest rate of complications of diagnostic and therapeutic bronchoscopic procedures in acute clinical circumstances.

Common respiratory viral infections: Bilateral versus unilateral bronchoalveolar lavage versus endotracheal aspiration

Data about the diagnostic efficiency of bilateral bronchoalveolar lavage (BAL) samples and endotracheal aspirates (EA) testing for common viral respiratory infections are scarce. We analyzed data from 167 cases, where bilateral BAL samples were tested, and from 101 cases, where BAL samples and EA were tested. Multiplex polymerase chain reaction (PCR) was performed with the fast track diagnostics viral respiratory panel, producing data on the adenovirus, coronavirus, enterovirus, human metapneumovirus, bocavirus, influenza virus, parainfluenza virus, rhinovirus, and respiratory syncytial virus status of patients with respiratory disease symptoms. In the bilateral BAL cohort, 46 (27.5%) cases were positive for at least one of the viruses mentioned above in both samples. Discrepant results (virus not detected on one side) were seen in six (3.6%) cases. In the BAL versus EA cohort, 12 (11.9%) cases were positive in both materials, discrepant results (only one material being positive) were observed in 11 (10.9%) cases, with seven (63.6%) BAL samples, and four (36.4%) EA being positive. Bilateral sampling does not significantly improve the diagnostic efficiency of BAL for the detection of common respiratory viral pathogens via PCR. The diagnostic quality of EA and BAL samples for the detection of common viral respiratory pathogens is comparable.

An overview of guidelines for the management of hospital-acquired and ventilator-associated pneumonia caused by multidrug-resistant Gram-negative bacteria

PURPOSE OF REVIEW

Multidrug-resistant (MDR) Gram-negative pathogens in hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are associated with poor clinical outcomes. These pathogens represent a global threat with few therapeutic options. In this review, we discuss current guidelines for the empiric management of HAP/VAP caused by MDR Gram-negative pathogens.

RECENT FINDINGS

The incidence of MDR Gram-negative bacteria is rising among cases of nosocomial pneumonia, such that it is now becoming a significant challenge for clinicians. Adherence to international guidelines may ensure early and adequate antimicrobial therapy, guided by local microbiological data and awareness of the risk factors for MDR bacteria.

SUMMARY

Due to the increasing prevalence of HAP/VAP caused by MDR Gram-negative pathogens, management should be guided by the local ecology and the patient's risk factors for MDR pathogens. The main risk factors are prior hospitalization for at least 5 days, prior use of broad-spectrum antibiotics, prior colonization with resistant pathogens, admission to hospital settings with high rates of MDR pathogens, and septic shock at the time of diagnosis with nosocomial pneumonia.

Multicenter evaluation of a syndromic rapid multiplex PCR test for early adaptation of antimicrobial therapy in adult patients with pneumonia

Background

Improving timeliness of pathogen identification is crucial to allow early adaptation of antibiotic therapy and improve prognosis in patients with pneumonia. We evaluated the relevance of a new syndromic rapid multiplex PCR test (rm-PCR) on respiratory samples to guide empirical antimicrobial therapy in adult patients with community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), and ventilator-acquired pneumonia (VAP).

Methods

This retrospective multicenter study was conducted in four French university hospitals. Respiratory samples were obtained from patients with clinical and radiological signs of pneumonia and simultaneously tested using conventional microbiological methods and the rm-PCR. A committee composed of an intensivist, a microbiologist, and an infectious diseases specialist retrospectively assessed all medical files and agreed on the most appropriate antimicrobial therapy for each pneumonia episode, according to the results of rm-PCR and blinded to the culture results. The rm-PCR-guided antimicrobial regimen was compared to the empirical treatment routinely administered to the patient in standard care.

Results

We included 159 pneumonia episodes. Most patients were hospitalized in intensive care units (n = 129, 81%), and episodes were HAP (n = 68, 43%), CAP (n = 54, 34%), and VAP (n = 37, 23%). Conventional culture isolated ≥ 1 microorganism(s) at significant level in 95 (60%) patients. The syndromic rm-PCR detected at least one bacteria in 132 (83%) episodes. Based on the results of the rm-PCR, the multidisciplinary committee proposed a modification of the empirical therapy in 123 (77%) pneumonia episodes. The modification was a de-escalation in 63 (40%), an escalation in 35 (22%), and undetermined in 25 (16%) patients. In microbiologically documented episodes (n = 95), the rm-PCR increased appropriateness of the empirical therapy to 83 (87%), as compared to 73 (77%) in routine care.

Conclusions

Use of a syndromic rm-PCR test has the potential to reduce unnecessary antimicrobial exposure and increase the appropriateness of empirical antibiotic therapy in adult patients with pneumonia.

Comparing current US and European guidelines for nosocomial pneumonia

PURPOSE OF REVIEW

In the last 2 years, two major guidelines for the management of nosocomial pneumonia have been published: The International European Respiratory Society/European Society of Intensive Care Medicine/European Society of Clinical Microbiology and Infectious Diseases/Asociación Latinoamericana de Toráx guidelines for the management of hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) and the American guidelines for management of adults with HAP and VAP; both the guidelines made important clinical recommendations for the management of patients.

RECENT FINDINGS

With the increasing emergence of multidrug resistant (MDR) organisms, paired with a relative reduction in new antibiotic development, nosocomial infections have become one of the most significant issues affecting global healthcare today. Despite several stark differences between the European and American guidelines, they are in agreement about many aspects of nosocomial pneumonia management.

SUMMARY

American and European guidelines promote prompt and appropriate empiric treatment which is immediately guided by local microbiological data, followed by an adequate de-escalation protocol based on culture results with a 1-week course of treatment. Both also questioned the use of biomarkers in HAP/VAP, whether as part of the diagnosis or daily assessment of patients. On the contrary, they have conflicting views in regards to the optimum method of diagnosis, the risk factors used to stratify patients, the use of clinical scoring systems and the various antibiotic classes used. All were presented with varying levels of evidence to support these differences in opinion, indicating that further research into these areas is required before a consensus can be agreed upon.

Ventilator-Associated Pneumonia: Diagnostic Test Stewardship and Relevance of Culturing Practices

PURPOSE OF REVIEW

Ventilator-associated pneumonia (VAP) is one of the most common infections in the ICU. Prompt diagnosis is vital as mortality increases with delayed antibiotic therapy. However, accurate diagnosis is challenging due to non-specific clinical features in a complicated patient cohort. Microbiological culture data remains a crucial aspect in confirming diagnosis.

RECENT FINDINGS

Literature data comparing the benefit of invasive respiratory sampling to non-invasive is inconclusive. Differences in culturing practices translate in overidentification of organisms of unclear significance. Positive culture data in a low pre-test probability does not differentiate between true infection and colonization resulting in overtreatment. Furthermore, there are also opportunities for modifying the reporting of respiratory tract cultures that can better guide antimicrobial therapy. Under the umbrella of antimicrobial stewardship, diagnostic stewardship can be incorporated to create a systematic approach that would target culturing practices to match the right pre-test probability. Ideal outcome will be targeting cultures to the right patient population and minimizing unnecessary treatment.

New guidelines for hospital-acquired pneumonia/ventilator-associated pneumonia: USA vs. Europe

PURPOSE OF REVIEW

The International ERS/ESICM/ESCMID/ALAT guidelines for the management of hospital-acquired pneumonia and ventilator-associated pneumonia were published in 2017 whilst the American guidelines for Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia were launched in 2016 by the Infectious Diseases Society of America/ATS. Both guidelines made updated recommendations based on the most recent evidence sharing not only some parallelisms but also important conceptual differences.

RECENT FINDINGS

Contemporary therapy for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) emphasizes the importance of prompt and appropriate antimicrobial therapy. There is an implicit risk, when appropriate means broad spectrum, that liberal use of antimicrobial combinations will encourage the emergence of multidrug resistant (MDR), extensively drug-resistant (XDR) and pandrug-resistant bacteria (PDR) and generate untreatable infections, including carbapenemase resistant infections.

SUMMARY

American and European guidelines have many areas of common agreement such as limiting antibiotic duration. Both guidelines were in favour of a close clinical assessment. Neither recommended a regular use of biomarkers but only in specific circumstances such as dealing with MDR and treatment failure. Risk factor prediction for MDR differed and whilst American guidelines focus on organ failure, the European ones did it in local ecology and septic shock.

Nosocomial Infections and Ventilator-Associated Pneumonia in Cancer Patients

Nosocomial infections or healthcare-acquired infections are a common cause of increased morbidity and mortality among hospitalized patients. Cancer patients are at an increased risk for these infections due to their immunosuppressed states. Considering these adverse effects on and the socioeconomic burden, efforts should be made to minimize the transmission of these infections and make the hospitals a safer environment. These infection rates can be significantly reduced by the implementing and improving compliance with the “care bundles.”

This chapter will address the common nosocomial infections such as ventilator-associated pneumonia (VAP), catheter-associated urinary tract infections (CAUTI), and surgical site infections (SSI), including preventive strategies and care bundles for the same.

Emerging strategies for the noninvasive diagnosis of nosocomial pneumonia

Introduction: Hospital-acquired pneumonia is a common and therapeutically challenging diagnosis that can lead to severe sepsis, critical illness, and respiratory failure. In this review, we focus on efforts to enhance microbiological diagnosis of hospital-acquired pneumonia, including ventilator-associated pneumonia.

Areas covered: A systematic literature review was conducted by searching Medline from inception to December 2018, including hand-searching of the reference lists for additional studies. The search strategy comprised the following common search terms: hospital pneumonia OR nosocomial pneumonia OR noninvasive OR molecular diagnostic tests (OR point-of-care systems OR VOC [i.e. volatile organic compounds]) OR rapid (or simple or quick test), including brand names for the most common commercial tests.

Expert opinion: In recent years, the microbiological diagnosis of respiratory pathogens has improved significantly by the development and implementation of molecular diagnostic tests for pneumonia. Real-time polymerase chain reaction, hybridization, and mass spectrometry-based platforms dominate the scene, with microarray-based assays, multiplex polymerase chain reaction, and MALDI-TOF mass spectrometry capable of detecting the determinants of antimicrobial resistance (mainly β-lactamase genes). Introducing these assays into routine clinical practice for rapid identification of the causative microbes and their resistance patterns could transform the care of pneumonia, improving antimicrobial selection, de-escalation, and stewardship.

Update on ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) is the most frequent life-threatening nosocomial infection in intensive care units. The diagnostic is difficult because radiological and clinical signs are inaccurate and could be associated with various respiratory diseases. The concept of infection-related ventilator-associated complication has been proposed as a surrogate of VAP to be used as a benchmark indicator of quality of care. Indeed, bundles of prevention measures are effective in decreasing the VAP rate. In case of VAP suspicion, respiratory secretions must be collected for bacteriological secretions before any new antimicrobials. Quantitative distal bacteriological exams may be preferable for a more reliable diagnosis and therefore a more appropriate use antimicrobials. To improve the prognosis, the treatment should be adequate as soon as possible but should avoid unnecessary broad-spectrum antimicrobials to limit antibiotic selection pressure. For empiric treatments, the selection of antimicrobials should consider the local prevalence of microorganisms along with their associated susceptibility profiles. Critically ill patients require high dosages of antimicrobials and more specifically continuous or prolonged infusions for beta-lactams. After patient stabilization, antimicrobials should be maintained for 7-8 days. The evaluation of VAP treatment based on 28-day mortality is being challenged by regulatory agencies, which are working on alternative surrogate endpoints and on trial design optimization.

Pneumonia in mechanically ventilated patients: no diagnostic and prognostic value of different quantitative tracheal aspirates thresholds

BACKGROUND

Diagnosis of pneumonia in ventilated patients is challenging due to the lack of specific and definitive clinical symptoms, laboratory data or radiological abnormalities.

METHODS

Based on quantitative tracheal aspirate (QTA) results, three groups of patients were compared: <10⁵ cfu/ml, ≥10⁵ cfu/ml and <10⁶ cfu/ml, and ≥10⁶ cfu/ml. We recorded demographic variables, underlying diseases and severity of illness at ICU admission. On the day of pneumonia diagnosis, we registered temperature, leukocyte count, C-reactive protein, Sequential Organ Failure Assessment (SOFA) score, clinical pulmonary infection score (CPIS) and adequacy of empirical antimicrobial therapy.

RESULTS

In 231 episodes, clinical presentation, laboratory data, severity of illness, CPIS, the presence of bacteremia and radiological score did not differ among the three groups. ICU and hospital mortalities were also similar in the three groups. Factors independently associated with in-hospital mortality were age, SOFA score and inappropriate antimicrobial therapy. The bacterial burden in the QTA was not included in the model.

CONCLUSIONS

Quantification of tracheal aspirate samples may not be necessary in ventilated patients clinically suspected of having nosocomial pneumonia.

Management of Adults With Hospital-acquired and Ventilator-associated Pneumonia: 2016 Clinical Practice Guidelines by the Infectious Diseases Society of America and the American Thoracic Society

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.These guidelines are intended for use by healthcare professionals who care for patients at risk for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), including specialists in infectious diseases, pulmonary diseases, critical care, and surgeons, anesthesiologists, hospitalists, and any clinicians and healthcare providers caring for hospitalized patients with nosocomial pneumonia. The panel's recommendations for the diagnosis and treatment of HAP and VAP are based upon evidence derived from topic-specific systematic literature reviews.

Short-course versus prolonged-course antibiotic therapy for hospital-acquired pneumonia in critically ill adults

BACKGROUND

Pneumonia is the most common hospital-acquired infection affecting patients in the intensive care unit (ICU). However, current national guidelines for the treatment of hospital-acquired pneumonia (HAP) are several years old and the diagnosis of pneumonia in mechanically ventilated patients (VAP) has been subject to considerable recent attention. The optimal duration of antibiotic therapy for HAP in the critically ill is uncertain.

OBJECTIVES

To assess the effectiveness of short versus prolonged-course antibiotics for HAP in critically ill adults, including patients with VAP.

SEARCH METHODS

We searched CENTRAL (2015, Issue 5), MEDLINE (1946 to June 2015), MEDLINE in-process and other non-indexed citations (5 June 2015), EMBASE (2010 to June 2015), LILACS (1982 to June 2015) and Web of Science (1955 to June 2015).

SELECTION CRITERIA

We considered all randomised controlled trials (RCTs) comparing a fixed 'short' duration of antibiotic therapy with a 'prolonged' course for HAP (including patients with VAP) in critically ill adults.

DATA COLLECTION AND ANALYSIS

Two review authors conducted data extraction and assessment of risk of bias. We contacted trial authors for additional information.

MAIN RESULTS

We identified six relevant studies involving 1088 participants. This included two new studies published after the date of our previous review (2011). There was substantial variation in participants, in the diagnostic criteria used to define an episode of pneumonia, in the interventions and in the reported outcomes. We found no evidence relating to patients with a high probability of HAP who were not mechanically ventilated. For patients with VAP, overall a short seven- or eight-day course of antibiotics compared with a prolonged 10- to 15-day course increased 28-day antibiotic-free days (two studies; N = 431; mean difference (MD) 4.02 days; 95% confidence interval (CI) 2.26 to 5.78) and reduced recurrence of VAP due to multi-resistant organisms (one study; N = 110; odds ratio (OR) 0.44; 95% CI 0.21 to 0.95), without adversely affecting mortality and other recurrence outcomes. However, for cases of VAP specifically due to non-fermenting Gram-negative bacilli (NF-GNB), recurrence was greater after short-course therapy (two studies, N = 176; OR 2.18; 95% CI 1.14 to 4.16), though mortality outcomes were not significantly different. One study found that a three-day course of antibiotic therapy for patients with suspected HAP but a low Clinical Pulmonary Infection Score (CPIS) was associated with a significantly lower risk of superinfection or emergence of antimicrobial resistance, compared with standard (prolonged) course therapy.

AUTHORS' CONCLUSIONS

On the basis of a small number of studies and appreciating the lack of uniform definition of pneumonia, we conclude that for patients with VAP not due to NF-GNB a short, fixed course (seven or eight days) of antibiotic therapy appears not to increase the risk of adverse clinical outcomes, and may reduce the emergence of resistant organisms, compared with a prolonged course (10 to 15 days). However, for patients with VAP due to NF-GNB, there appears to be a higher risk of recurrence following short-course therapy. These findings do not differ from those of our previous review and are broadly consistent with current guidelines. There are few data from RCTs comparing durations of therapy in non-ventilated patients with HAP, but on the basis of a single study, short-course (three-day) therapy for HAP appears not to be associated with worse clinical outcome, and may reduce the risk of subsequent infection or the emergence of resistant organisms when there is low probability of pneumonia according to the CPIS.

Quantitative culture of endotracheal aspirate and BAL fluid samples in the management of patients with ventilator-associated pneumonia: a randomized clinical trial

OBJECTIVE:

To compare 28-day mortality rates and clinical outcomes in ICU patients with ventilator-associated pneumonia according to the diagnostic strategy used.

METHODS:

This was a prospective randomized clinical trial. Of the 73 patients included in the study, 36 and 37 were randomized to undergo BAL or endotracheal aspiration (EA), respectively. Antibiotic therapy was based on guidelines and was adjusted according to the results of quantitative cultures.

RESULTS:

The 28-day mortality rate was similar in the BAL and EA groups (25.0% and 37.8%, respectively; p = 0.353). There were no differences between the groups regarding the duration of mechanical ventilation, antibiotic therapy, secondary complications, VAP recurrence, or length of ICU and hospital stay. Initial antibiotic therapy was deemed appropriate in 28 (77.8%) and 30 (83.3%) of the patients in the BAL and EA groups, respectively (p = 0.551). The 28-day mortality rate was not associated with the appropriateness of initial therapy in the BAL and EA groups (appropriate therapy: 35.7% vs. 43.3%; p = 0.553; and inappropriate therapy: 62.5% vs. 50.0%; p = 1.000). Previous use of antibiotics did not affect the culture yield in the EA or BAL group (p = 0.130 and p = 0.484, respectively).

CONCLUSIONS:

In the context of this study, the management of VAP patients, based on the results of quantitative endotracheal aspirate cultures, led to similar clinical outcomes to those obtained with the results of quantitative BAL fluid cultures.

Quantitative versus qualitative cultures of respiratory secretions for clinical outcomes in patients with ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) is a common infectious disease in intensive care units (ICUs). The best diagnostic approach to resolve this condition remains uncertain.

OBJECTIVES

To evaluate whether quantitative cultures of respiratory secretions and invasive strategies are effective in reducing mortality in immunocompetent patients with VAP, compared with qualitative cultures and non-invasive strategies. We also considered changes in antibiotic use, length of ICU stay and mechanical ventilation.

SEARCH METHODS

We searched CENTRAL (2014, Issue 9), MEDLINE (1966 to October week 2, 2014), EMBASE (1974 to October 2014) and LILACS (1982 to October 2014).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing respiratory samples processed quantitatively or qualitatively, obtained by invasive or non-invasive methods from immunocompetent patients with VAP and which analysed the impact of these methods on antibiotic use and mortality rates.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed the trials identified in the search results and assessed studies for suitability, methodology and quality. We analysed data using Review Manager software. We pooled the included studies to yield the risk ratio (RR) for mortality and antibiotic change with 95% confidence intervals (CI).

MAIN RESULTS

Of the 5064 references identified from the electronic databases (605 from the updated search in October 2014), five RCTs (1367 patients) met the inclusion criteria. Three studies compared invasive methods using quantitative cultures versus non-invasive methods using qualitative cultures, and we used them to answer the main objective of this review. The other two studies compared invasive versus non-invasive methods, both using quantitative cultures. We combined all five studies to compare invasive versus non-invasive interventions for diagnosing VAP. The studies that compared quantitative and qualitative cultures (1240 patients) showed no statistically significant differences in mortality rates (RR 0.91; 95% CI 0.75 to 1.11). The analysis of all five RCTs showed there was no evidence of reduction in mortality in the invasive group versus the non-invasive group (RR 0.93; 95% CI 0.78 to 1.11). There were no significant differences between the interventions with respect to the number of days on mechanical ventilation, length of ICU stay or antibiotic change.

AUTHORS' CONCLUSIONS

There is no evidence that the use of quantitative cultures of respiratory secretions results in reduced mortality, reduced time in ICU and on mechanical ventilation, or higher rates of antibiotic change when compared to qualitative cultures in patients with VAP. We observed similar results when invasive strategies were compared with non-invasive strategies.

Endotracheal aspirate and bronchoalveolar lavage fluid analysis: interchangeable diagnostic modalities in suspected ventilator-associated pneumonia?

Authoritative guidelines state that the diagnosis of ventilator-associated pneumonia (VAP) can be established using either endotracheal aspirate (ETA) or bronchoalveolar lavage fluid (BALF) analysis, thereby suggesting that their results are considered to be in accordance. Therefore, the results of ETA Gram staining and semiquantitative cultures were compared to the results from a paired ETA-BALF analysis. Different thresholds for the positivity of ETAs were assessed. This was a prospective study of all patients who underwent bronchoalveolar lavage for suspected VAP in a 27-bed university intensive care unit during an 8-year period. VAP was diagnosed when ≥ 2% of the BALF cells contained intracellular organisms and/or when BALF quantitative culture revealed ≥ 10(4) CFU/ml of potentially pathogenic microorganisms. ETA Gram staining and semiquantitative cultures were compared to the results from paired BALF analysis by Cohen's kappa coefficients. VAP was suspected in 311 patients and diagnosed in 122 (39%) patients. In 288 (93%) patients, the results from the ETA analysis were available for comparison. Depending on the threshold used and the diagnostic modality, VAP incidences varied from 15% to 68%. For the diagnosis of VAP, the most accurate threshold for positivity of ETA semiquantitative cultures was moderate or heavy growth, whereas the optimal threshold for BALF Gram staining was ≥ 1 microorganisms per high power field. The Cohen's kappa coefficients were 0.22, 0.31, and 0.60 for ETA and paired BALF Gram stains, cultures, and BALF Gram stains, respectively. Since the ETA and BALF Gram stains and cultures agreed only fairly, they are probably not interchangeable for diagnosing VAP.

Influence of bronchoscopy on the diagnosis of and outcomes from ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) is a common healthcare-associated infection affecting as many as 27% of mechanically ventilated patients. Ventilator-associated pneumonia is an important source of morbidity and mortality in the surgical intensive care unit (SICU). The optimal diagnostic method for VAP has remained controversial and the role of therapeutic bronchoscopy in the clearance of pulmonary secretions with VAP, in essence source control, remains unknown. Our unit utilizes bronchoscopy inconsistently for these purposes and we chose to evaluate its effectiveness in our patient population with the hypothesis that bronchoscopic diagnosis and therapy results in lower mortality rates and faster clinical resolution.

METHODS

We analyzed retrospectively all patients treated for VAP in a single SICU between September 2003 and December 2011. Patients were divided into groups based upon diagnostic method and receipt of therapeutic bronchoscopy, and were analyzed for differences in time to clinical resolution and mortality.

RESULTS

A total of 360 patients were included in the study, including 493 episodes of VAP. The diagnostic bronchoscopy group had statistically higher APACHE II scores (p=0.02) and fewer days in hospital prior to diagnosis (p=0.02) when compared with the non-invasive diagnosis group. Diagnostic bronchoscopy was associated with shorter length of stay and shorter duration of antibiotics whereas receipt of a therapeutic bronchoscopy was associated with the opposite effects by multivariable analysis.

CONCLUSION

Our hypothesis was disproved and our findings are similar to those found in recent publications. This study supports no definitive conclusions, but further consideration of the role of bronchoscopy is urged in both the diagnosis and treatment of VAP. In our population, bronchoscopy for diagnostic or therapeutic purposes in VAP was not associated with better outcomes. However, differences in baseline characteristics suggest a randomized trial may be needed to answer more completely this question.

Prompting physicians to address a daily checklist for antibiotics: do we need a co-pilot in the ICU?

PURPOSE OF REVIEW

Failed opportunities to reduce morbidity and mortality occur when evidence-based therapies are not fully implemented in clinical practice. We reviewed the recent literature on implementation strategies in the intensive care unit, with particular attention to antibiotic therapy.

RECENT FINDINGS

Emphasis in implementation science has shifted to new models that focus more on direct, point-of-care interaction with providers as opposed to an administrative or top-down approach. Prompting physicians to use a multifaceted checklist was associated with a decrease in severity-adjusted mortality and length of stay. The majority of the benefit appears to correlate with decreased use of empirical antibiotics. A subsequent study demonstrated that face-to-face prompting regarding empirical antibiotics alone was still superior to an electronic checklist, but that long-term changes in use of empirical antibiotics resulted from the previous prompting study. Other studies demonstrate that checklists result in enhanced communication between caregivers, which may be a major explanation for their benefit.

SUMMARY

Newer implementation strategies focused on real-time, point-of-care interventions have been associated with greater impact. The most common of these new interventions is use of checklists. Greater checklist use has led to the realization that a prompting or forcing function is required for optimal benefit.

Evaluation of semi-quantitative scoring of Gram staining or semi-quantitative culture for the diagnosis of ventilator-associated pneumonia: a retrospective comparison with quantitative culture

Background

Semi-quantitative Gram stain and culture methods are still commonly used for diagnosing ventilator-associated pneumonia (VAP), due to its convenience. Only a few studies, however, have assessed the reliability of these methods when compared with quantitative cultures, a current standard for the diagnosis of VAP. The objective of this study was to assess the utility of semi-quantitative scores obtained using Gram stains and cultures of endotracheal aspirates when compared with quantitative cultures in the diagnosis of VAP.

Methods

A retrospective chart review of mechanically ventilated patients with clinically suspected VAP in a single intensive care unit was performed. Semi-quantitative scores of Gram stains or culture results were compared with quantitative culture results of endotracheal aspirate for the diagnosis of VAP in 136 samples for 51 patients.

Results

The semi-quantitative scores of Gram stains and the semi-quantitative culture results significantly correlated with the log value of the quantitative culture results (r_s = 0.64 and 0.75). When using a log count ≥6 of quantitative cultures as the reference standard for the diagnosis of VAP, the sensitivity and specificity was 95% and 61% for Gram stain score of ≥1+, and was 42% and 96% for Gram stain score ≥3+, respectively. The sensitivity and specificity was 96% and 40% for the semi-quantitative culture score of ≥2+, and was 59% and 86% for the semi-quantitative culture score of ≥3+, respectively.

Conclusions

Absence of bacteria in semi-quantitative Gram stain and poor growth (≤1+) in semi-quantitative culture method could be utilized to exclude the possibility of VAP, whereas detection of abundant (≥3+) bacteria in semi-quantitative Gram stain could be utilized to strongly suspect VAP.

Suspected ventilator-associated respiratory infection in severely ill patients: a prospective observational study

Introduction

Ventilator-associated respiratory infection (VARI) is an important cause of morbidity in critically-ill patients. Clinical trials performed in heterogeneous populations have suggested there are limited benefits from invasive diagnostic testing to identify patients at risk or to target antimicrobial therapy. However, multiple patient subgroups (for example, immunocompromised, antibiotic-treated) have traditionally been excluded from randomization. We hypothesized that a prospective surveillance study would better identify patients with suspected VARI (sVARI) at high risk for adverse clinical outcomes, and who might be specifically targeted in future trials.

Methods

We performed a prospective observational study in all patients ventilated for greater than 48 hours. sVARI was identified by surveillance for changes in white blood cell count, temperature, sputum, and/or new chest X-ray infiltrates. Indices of disease co-morbidity, as well as mortality, duration of mechanical ventilation, and length of hospital or ICU stay were correlated with sVARI.

Results

Of 1806 patients admitted to the ICU over 14 months, 267 were ventilated for greater than 48 hours, and 77 developed sVARI. Incidence of sVARI was associated with iatrogenic immunosuppression or admission for respiratory illness. Any sVARI, whether suspected ventilator-associated pneumonia (sVAP) or ventilator-associated tracheobronchitis (sVAT), was associated with increased length of stay and duration of mechanical ventilation.

Conclusions

Clinical surveillance for sVARI identifies patients at risk for increased morbidity. Iatrogenically immunosuppressed patients, a subgroup previously excluded from randomized clinical trials, represent a growing proportion of the critically-ill at risk for sVARI who might be targeted for future investigations on diagnostic or therapeutic modalities.

Storage of bronchoalveolar lavage fluid and accuracy of microbiologic diagnostics in the ICU: a prospective observational study

INTRODUCTION

Early initiation of appropriate antimicrobial treatment is a cornerstone in managing pneumonia. Because microbiologic processing may not be available around the clock, optimal storage of specimens is essential for accurate microbiologic identification of pathogenetic bacteria. The aim of our study was to determine the accuracy of two commonly used storage approaches for delayed processing of bronchoalveolar lavage in critically ill patients with suspected pneumonia.

METHODS

This study included 132 patients with clinically suspected pneumonia at two medical intensive care units of a tertiary care hospital. Bronchoalveolar lavage samples were obtained and divided into three aliquots: one was used for immediate culture, and two, for delayed culture (DC) after storage for 24 hours at 4°C (DC4) and -80°C (DC-80), respectively.

RESULTS

Of 259 bronchoalveolar lavage samples, 84 (32.4%) were positive after immediate culture with 115 relevant culture counts (≥104 colony-forming units/ml). Reduced (<104 colony-forming units/ml) or no growth of four and 57 of these isolates was observed in DC4 and DC-80, respectively. The difference between mean bias of immediate culture and DC4 (-0.035; limits of agreement, -0.977 to 0.906) and immediate culture and DC-80 (-1.832; limits of agreement, -4.914 to 1.267) was -1.788 ± 1.682 (P < 0.0001). Sensitivity and negative predictive value were 96.5% and 97.8% for DC4 and 50.4% and 75.4% for DC-80, respectively; the differences were statistically significant (P < 0.0001).

CONCLUSIONS

Bronchoalveolar lavage samples can be processed for culture when stored up to 24 hours at 4°C without loss of diagnostic accuracy. Delayed culturing after storage at -80°C may not be reliable, in particular with regard to Gram-negative bacteria.

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.

Evolution of surfactant protein-D levels in children with ventilator-associated pneumonia

RATIONALE

The pathobiology of ventilator-associated pneumonia (VAP) in children is poorly understood; investigation has been limited by lack of universally applied diagnostic criteria and reliable biomarkers for this condition.

OBJECTIVES

We evaluated the clinical pulmonary infection score (CPIS) in diagnosing VAP and prospectively characterized the relationship between surfactant protein-D (SP-D) metabolism and VAP.

METHODS

Children admitted to an Egyptian PICU requiring intubation were screened for the absence of primary pulmonary pathology. Thirty-nine children underwent two evaluations: during the first 36 hr following intubation and after 4 days of mechanical ventilation. During both, bronchoalveolar lavage fluid (BALF) was obtained for culture and SP-D assay. CPIS was computed during the second evaluation.

RESULTS

Optimum performance of the CPIS against BALF culture occurred at a cutoff value of 6, (ROC AUC of 0.89 ± 0.05). Children who developed VAP had significantly higher SP-D levels, both preceding (129.9 ± 33.5 ng/ml at the 1st BAL)-and following positive BALF culture (249.5 ± 51.2 ng/ml at the 2nd BAL), compared to children whose BALF remained sterile (62.6 ± 18.1 ng/ml and 64.9 ± 9.4 ng/ml; P < 0.001). This increase in SP-D levels was most evident in children infected with Pseudomonas aeruginosa compared to children with Klebsiella pneumonia or S. aureus.

CONCLUSIONS

The CPIS performed well against BALF culture. We observed a bacterial species-specific difference in SP-D levels in children who developed VAP; this change preceded detection of infection by CPIS or BALF culture.

Quantitative versus qualitative cultures of respiratory secretions for clinical outcomes in patients with ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) is a common infectious disease in intensive care units (ICUs). The best diagnostic approach to resolve this condition remains uncertain.

OBJECTIVES

To evaluate whether quantitative cultures of respiratory secretions are effective in reducing mortality in immunocompetent patients with VAP, compared with qualitative cultures. We also considered changes in antibiotic use, length of ICU stay and mechanical ventilation.

SEARCH METHODS

We searched The Cochrane Library, Cochrane Central Register of Controlled Trials (CENTRAL) Issue 2, 2011, which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to June Week 4, 2011), EMBASE (1974 to June 2011) and LILACS (1982 to June 2011).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing respiratory samples processed quantitatively or qualitatively, obtained by invasive or non-invasive methods from immunocompetent patients with VAP and which analysed the impact of these methods on antibiotic use and mortality rates.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed and trials identified in the search results and assessed studies for suitability, methodology and quality. We analysed data using Review Manager software. We pooled the included studies to yield the risk ratio (RR) for mortality and antibiotic change with 95% confidence intervals (CI).

MAIN RESULTS

Of the 4459 references identified from the electronic databases, five RCTs (1367 patients) met the inclusion criteria. Three studies compared invasive methods using quantitative cultures versus non-invasive methods using qualitative cultures, and were used to answer the main objective of this review. The other two studies compared invasive versus non-invasive methods, both using quantitative cultures. We combined all five studies to compare invasive versus non-invasive interventions for diagnosing VAP. The studies that compared quantitative and qualitative cultures (1240 patients) showed no statistically significant differences in mortality rates (RR 0.91; 95% CI 0.75 to 1.11). The analysis of all five RCTs showed there was no evidence of reduction in mortality in the invasive group versus the non-invasive group (RR 0.93; 95% CI 0.78 to 1.11). There were no significant differences between the interventions with respect to the number of days on mechanical ventilation, length of ICU stay or antibiotic change.

AUTHORS' CONCLUSIONS

There is no evidence that the use of quantitative cultures of respiratory secretions results in reduced mortality, reduced time in ICU and on mechanical ventilation, or higher rates of antibiotic change when compared to qualitative cultures in patients with VAP. Similar results were observed when invasive strategies were compared with non-invasive strategies.

Incidence, risk stratification, antibiogram of pathogens isolated and clinical outcome of ventilator associated pneumonia

Background:

The initial empirical therapy of Ventilator Associated Pneumonia (VAP) modified based on the knowledge of local microbiological data is associated with decreased morbidity and mortality. The objective was to find the incidence and risk factors associated with VAP, the implicated pathogens and their susceptibility pattern as well as to assess the final clinical outcome in VAP.

Materials and Methods:

This was a prospective cohort study of 107 patients taken on ventilatory support for two or more days and those not suffering from pneumonia prior were to be taken on ventilator. The study was done over a period of one year. VAP was diagnosed using clinical pulmonary infection score of >6. The mortality, incidence of VAP, frequency of different pathogens isolated, their antibiotic sensitivity pattern, duration of mechanical ventilation and duration of hospital stay were assessed.

Statistical Analysis:

Univariate analysis, χ² test and paired t-test.

Results:

The incidence of VAP was 28.04%. Mortality in VAP group was 46.67%, while in the non-VAP group was 27.28%. High APACHE II score was associated with a high mortality rate as well as increased incidence of VAP. The most common organisms isolated from endotracheal aspirate of patients who developed VAP were Pseudomonas aeruginosa, Methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae and Acinetobacter baumannii. Most strains of Pseudomonas (55.56%) were resistant to commonly used beta-lactam antibiotics known to be effective against Pseudomonas. All strains of Staphylococcus aureus were MRSA and most isolates of K. pneumoniae (85.71%) were extended-spectrum beta-lactamase producing. About 50% isolates of Acinetobacter were resistant to carbapenems. Mortality was highest for infections caused by A. baumannii (83.33%) and K. pneumoniae (71.42%).

Conclusions:

APACHE II score can be used to stratify the risk of development of VAP and overall risk of mortality. Drug-resistant strains of various organisms are an important cause of VAP in our setting.

Short-course versus prolonged-course antibiotic therapy for hospital-acquired pneumonia in critically ill adults

BACKGROUND

Pneumonia is the most common hospital-acquired infection affecting patients in the intensive care unit (ICU). However, the optimal duration of antibiotic therapy for hospital-acquired pneumonia (HAP) is uncertain.

OBJECTIVES

To assess the effectiveness of short versus prolonged-course antibiotic administration for HAP in critically ill adults, including patients with ventilator-associated pneumonia (VAP).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), which includes the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1950 to February week 4, 2011), EMBASE (1974 to March 2011), LILACS (1985 to March 2011) and Web of Science (1985 to March 2011).

SELECTION CRITERIA

We considered all randomised controlled trials (RCTs) comparing fixed durations of antibiotic therapy, or comparing a protocol intended to limit duration of therapy with standard care, for HAP (including patients with VAP) in critically ill adults.

DATA COLLECTION AND ANALYSIS

Two review authors conducted data extraction and assessment of risk of bias. We contacted trial authors for additional information.

MAIN RESULTS

Eight studies (1703 patients) were included. Methodology varied considerably and we found little evidence regarding patients with a high probability of HAP who were not mechanically ventilated. For patients with VAP, a short seven to eight-day course of antibiotics compared with a prolonged 10 to 15-day course (three studies, N = 508) increased 28-day antibiotic-free days (odds ratio (OR) 4.02; 95% confidence interval (CI) 2.26 to 5.78) and reduced recurrence of VAP due to multi-resistant organisms (OR 0.44; 95% CI 0.21 to 0.95), without adversely affecting other outcomes. However, for cases of VAP due to non-fermenting Gram-negative bacilli (NF-GNB), recurrence was greater after short-course therapy (OR 2.18; 95% CI 1.14 to 4.16; two studies, N = 176), though other outcome measures did not significantly differ. Discontinuation strategies utilising clinical features (one study; N = 302) or procalcitonin (three studies; N = 323) led to a reduction in duration of therapy and, in the procalcitonin studies, increased 28-day antibiotic-free days (mean difference (MD) 2.80; 95% CI 1.39 to 4.21) without negatively affecting other outcomes.

AUTHORS' CONCLUSIONS

We conclude that for patients with VAP not due to NF-GNB, a short fixed-course (seven or eight days) antibiotic therapy may be more appropriate than a prolonged course (10 to 15 days). Use of an individualised strategy (incorporating clinical features or serum procalcitonin) appears to safely reduce duration of antibiotic therapy for VAP.

Severe, non-bacteremic infections in ICU patients

The present article is an update of the literature on various types of infections in ICU patients: ventilator-associated pneumonia, community-acquired pneumonia, the impact of the increasing vancomycin MIC in Staphylococcus aureus in the treatment of infections caused by this microorganism and the usefulness of biomarkers in identifying or ruling out septic complications in ICU patients. A multidisciplinary group of Spanish physicians with an interest in infections in critically-ill patients selected the most important recently published papers produced in the field. One of the members of the group discussed the content of each of the selected papers, with a critical appraisal by other members of the panel.

Clinical practice guidelines for hospital-acquired pneumonia and ventilator-associated pneumonia in adults

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are important causes of morbidity and mortality, with mortality rates approaching 62%. HAP and VAP are the second most common cause of nosocomial infection overall, but are the most common cause documented in the intensive care unit setting. In addition, HAP and VAP produce the highest mortality associated with nosocomial infection. As a result, evidence-based guidelines were prepared detailing the epidemiology, microbial etiology, risk factors and clinical manifestations of HAP and VAP. Furthermore, an approach based on the available data, expert opinion and current practice for the provision of care within the Canadian health care system was used to determine risk stratification schemas to enable appropriate diagnosis, antimicrobial management and nonantimicrobial management of HAP and VAP. Finally, prevention and risk-reduction strategies to reduce the risk of acquiring these infections were collated. Future initiatives to enhance more rapid diagnosis and to effect better treatment for resistant pathogens are necessary to reduce morbidity and improve survival.

[Positive bronchoalveolar lavage and quantitative cultures results in suspected late-onset ventilator associated penumonia evaluation--retrospective study]

INTRODUCTION

Bronchoalveolar lavage (BAL) with quantitative cultures has been used in order to increase ventilator associated pneumonia (VAP) diagnosis specificity, although the accurate technique for this entity diagnosis remains controversial.

OBJECTIVES

To evaluate the influence of using positive BAL and quantitative cultures results in microbiologic diagnosis and treatment of patients with suspected late VAP and prior antibiotherapy.

MATERIAL AND METHODS

Retrospective analysis of intensive care unit (UCI) patients, during a one year period, with clinical suspicion of late VAP and prior use of antibiotics that presented a growth in BAL cultures.

RESULTS

Of 243 BAL performed, there were 71 (29.2%) positive cultures (60 patients, 76.7% male, 54 ± 19 years). BAL was done after 13 days (median) of invasive mechanical ventilation, 11 days of ICU antibiotherapy and in the day in which a new antibiotic for VAP suspicion was started. Colony forming units (CFU)/ml count was performed in 71.8% and endotracheal aspirate (ETA) simultaneously collected for qualitative analysis in 85.9%. Therapeutic approach was changed in 38.0%: correction (16.9%), de-escalation (12.7%) and directed antibiotherapy start (8.4%). Therapeutic changes were made in the presence of CFU > 10(4) in 84.2% and in agreement with ETA in 70.8%. In cases in which antibiotherapy was maintained (62.0%), quantitative cultures would have allowed de-escalation in 9.1%. Changes in prescription were more frequent when CFU was > 10(4) (48.5%), comparing with situations in which counts were lower and BAL analysis was qualitative (28.9%), p = 0.091. There were no significant differences between patients submitted to different therapeutic approaches concerning to ICU mortality or length of stay.

CONCLUSION

In late onset VAP, positive BAL and quantitative cultures allowed therapeutic changes, leading to antibiotic adequacy and consumption reduction, which can however be maximised.

Multinational, observational study of procalcitonin in ICU patients with pneumonia requiring mechanical ventilation: a multicenter observational study

Introduction

The intent of this study was to determine whether serum procalcitonin (PCT) levels are associated with prognosis, measured as organ dysfunctions and 28-day mortality, in patients with severe pneumonia.

Methods

This was a multicenter, observational study of critically ill adult patients with pneumonia requiring mechanical ventilation conducted in 10 academic hospitals in Canada, the United States, and Central Europe. PCT was measured daily for 14 days using an immuno-luminometric assay.

Results

We included 175 patients, 57 with community acquired pneumonia (CAP), 61 with ventilator associated pneumonia (VAP) and 57 with hospital acquired pneumonia (HAP). Initial PCT levels were higher in CAP than VAP patients (median (interquartile range: IQR); 2.4 (0.95 to 15.8) vs. 0.7 (0.3 to 2.15), ng/ml, P < 0.001) but not significantly different to HAP (2.2 (0.4 to 8.0) ng/ml). The 28-day ICU mortality rate for all patients was 18.3% with a median ICU length of stay of 16 days (range 1 to 142 days). PCT levels were higher in non-survivors than in survivors. Initial and maximum PCT levels correlated with maximum Sequential Organ Failure Assessment (SOFA) score r² = 0.50 (95% CI: 0.38 to 0.61) and r² = 0.57 (0.46 to 0.66), respectively. Receiver operating curve (ROC) analysis on discrimination of 28-day mortality showed areas under the curve (AUC) of 0.74, 0.70, and 0.69 for maximum PCT, initial PCT, and Acute Physiology and Chronic Health Evaluation (APACHE) II score, respectively. The optimal cut-off to predict mortality for initial PCT was 1.1 ng/ml (odds ratio: OD 7.0 (95% CI 2.6 to 25.2)) and that for maximum PCT was 7.8 ng/ml (odds ratio 5.7 (95% CI 2.5 to 13.1)).

Conclusions

PCT is associated with the severity of illness in patients with severe pneumonia and appears to be a prognostic marker of morbidity and mortality comparable to the APACHE II score.

The Problems Diagnosing Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is the most common healthcare-associated infection in the intensive care unit. Clinical, radiological and microbiological criteria are used to make the diagnosis, but there is no consensus definition, as no individual criterion or combination of criteria offer sufficient diagnostic accuracy to support their sole use in defining VAP. Neither invasive bronchoscopic sampling nor less invasive quantitative tracheal aspirate, conveys an advantage when making the microbiological diagnosis of VAP. Of the scoring systems and definitions presently in use, the Clinical Pulmonary Infection Score (CPIS) has been shown to be prone to inter-observer variability; the US Centers for Disease Control (CDC) National Healthcare Safety Network (NHSN) definition relies heavily on subjective clinical criteria, and the Hospitals in Europe Link for Infection Control through Surveillance (HELICS) criteria employ similarly subjective clinical criteria with five different possibilities for microbiological diagnosis. The use of these different diagnostic methods leads to marked variation in the reported incidence of VAP. Clinical practice requires an objective and transferable definition for VAP so that we can improve the reporting, monitoring and treatment of VAP.

Diagnosis of ventilator-associated pneumonia

INTRODUCTION

Ventilator-associated pneumonia (VAP) is difficult to diagnose. Recent data suggest quantitative endotracheal aspirate (ETA) may be noninferior diagnostically to quantitative bronchoalveolar lavage (BAL). We hypothesized this would be the case.

METHODS

Blind quantitative ETA and BAL were performed on 150 consecutive ventilated patients with suspected VAP in a prospective single-centre medical intensive care unit study over a 2-year inclusion period. Patients were either antibiotic-naive or antibiotic-free for 72 hours. Diagnostic yield, Gram stain and culture results, and impact on antibiotic therapy were assessed. The independent impact of a positive BAL or ETA result on ventilator settings and 28-day mortality was calculated. The BAL/ETA safety was assessed hemodynamically.

RESULTS

Bronchoalveolar lavage had significantly higher diagnostic yield (49.3% vs 34.0%, P = .01), more frequent impact on antibiotic therapy (usually de-escalation) (48.0% vs 32.7%, P = .01), and greater sensitivity (64.1% vs 42.6%, P = .0003) than ETA. There was moderate intertest agreement and no difference in specificity and positive and negative predictive values. A positive BAL or ETA result did not independently alter the frequency of ventilator changes or 28-day mortality. Both procedures were well tolerated.

CONCLUSION

Quantitative BAL is safe and has greater diagnostic utility than ETA for VAP facilitates de-escalation. This study provides support for quantitative BAL in VAP diagnosis.

[Ventilator-associated pneumonia]

Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in critical care medicine and has been shown to be an independent risk factor for mortality. However, ventilator induced lung injury itself is probably only a minor factor predisposing to VAP. In contrast, invasive ventilation using an endotracheal tube is obviously a more important measure. Thus, microaspiration of potentially infectious secretion from the oropharynx into the trachea along the tube has been suggested to be the most critical pathophysiological event in the process of VAP development. Accordingly, non-invasive ventilation provides a decreased risk of VAP. Therefore, all measures aimed at averting microaspiration or shorten the duration of mechanical ventilation are appropriate to prevent VAP. Moreover, oropharyngeal decontamination may be helpful by reducing bacterial colonisation. Effectiveness of therapy depends on early treatment and therefore requires early diagnosis. With this aim combined clinical, radiologic, and microbiological parameters should be taken into account. Adequate antimicrobial therapy in due consideration for individual risk factors and local antibiotic resistance is the most important therapeutic measure.

Quantitative versus qualitative cultures of respiratory secretions for clinical outcomes in patients with ventilator-associated pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) is a common infectious disease in intensive care units (ICUs). The best diagnostic approach to resolve this condition remains uncertain.

OBJECTIVES

To evaluate whether quantitative cultures of respiratory secretions are effective in reducing mortality in immunocompetent patients with VAP, compared with qualitative cultures. We also considered changes in antibiotic use, length of ICU stay and mechanical ventilation.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, issue 4), which contains the Acute Respiratory Infections Group's Specialized Register; MEDLINE (1966 to December 2007); EMBASE (1974 to December 2007); and LILACS (1982 to December 2007).

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing respiratory samples processed quantitatively or qualitatively, obtained by invasive or non-invasive methods from immunocompetent patients with VAP, and which analyzed the impact of these methods on antibiotic use and mortality rates.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed and selected trials from the search results, and assessed studies for suitability, methodology and quality. We analyzed data using Review Manager software. We pooled the included studies to yield the risk ratio (RR) for mortality and antibiotic change with 95% confidence intervals (CI).

MAIN RESULTS

Of the 3931 references identified from the electronic databases, five RCTs (1367 patients) met the inclusion criteria. Three studies compared invasive methods using quantitative cultures versus non-invasive methods using qualitative cultures, and were used to answer the main objective of this review. The other two studies compared invasive versus non-invasive methods, both using quantitative cultures. All five studies were combined to compare invasive versus non-invasive interventions for diagnosing VAP. The studies that compared quantitative and qualitative cultures (1240 patients) showed no statistically significant differences in mortality rates (RR = 0.91, 95% CI 0.75 to 1.11). The analysis of all five RCTs showed there was no evidence of mortality reduction in the invasive group versus the non-invasive group (RR = 0.93, 95% CI 0.78 to 1.11). There were no significant differences between the interventions with respect to the number of days on mechanical ventilation, length of ICU stay or antibiotic change.

AUTHORS' CONCLUSIONS

There is no evidence that the use of quantitative cultures of respiratory secretions results in reduced mortality, reduced time in ICU and on mechanical ventilation, or higher rates of antibiotic change when compared to qualitative cultures in patients with VAP. Similar results were observed when invasive strategies were compared with non-invasive strategies.