Canadian Critical Care Trials Group. A randomized trial of diagnostic techniques for ventilator-associated pneumonia

Personalizing the Management of Pneumonia

Pneumonia is a highly prevalent disease with considerable morbidity and mortality. However, diagnosis and therapy still rely on antiquated methods, leading to the vast overuse of antimicrobials, which carries risks for both society and the individual. Furthermore, outcomes in severe pneumonia remain poor. Genomic techniques have the potential to transform the management of pneumonia through deep characterization of pathogens as well as the host response to infection. This characterization will enable the delivery of selective antimicrobials and immunomodulatory therapy that will help to offset the disorder associated with overexuberant immune responses.

Multidimensional Assessment of the Host Response in Mechanically Ventilated Patients with Suspected Pneumonia

Rationale: The identification of informative elements of the host response to infection may improve the diagnosis and management of bacterial pneumonia. Objectives: To determine whether the absence of alveolar neutrophilia can exclude bacterial pneumonia in critically ill patients with suspected infection and to test whether signatures of bacterial pneumonia can be identified in the alveolar macrophage transcriptome. Methods: We determined the test characteristics of alveolar neutrophilia for the diagnosis of bacterial pneumonia in three cohorts of mechanically ventilated patients. In one cohort, we also isolated macrophages from alveolar lavage fluid and used the transcriptome to identify signatures of bacterial pneumonia. Finally, we developed a humanized mouse model of Pseudomonas aeruginosa pneumonia to determine if pathogen-specific signatures can be identified in human alveolar macrophages. Measurements and Main Results: An alveolar neutrophil percentage less than 50% had a negative predictive value of greater than 90% for bacterial pneumonia in both the retrospective (n = 851) and validation cohorts (n = 76 and n = 79). A transcriptional signature of bacterial pneumonia was present in both resident and recruited macrophages. Gene signatures from both cell types identified patients with bacterial pneumonia with test characteristics similar to alveolar neutrophilia. Conclusions: The absence of alveolar neutrophilia has a high negative predictive value for bacterial pneumonia in critically ill patients with suspected infection. Macrophages can be isolated from alveolar lavage fluid obtained during routine care and used for RNA-Seq analysis. This novel approach may facilitate a longitudinal and multidimensional assessment of the host response to bacterial pneumonia.

A multicenter, randomized, double-blind study of ulimorelin and metoclopramide in the treatment of critically ill patients with enteral feeding intolerance: PROMOTE trial

PURPOSE

Enteral feeding intolerance (EFI) is a frequent problem in the intensive care unit (ICU), but current prokinetic agents have uncertain efficacy and safety profiles. The current study compared the efficacy and safety of ulimorelin, a ghrelin agonist, with metoclopramide in the treatment of EFI.

METHODS

One hundred twenty ICU patients were randomized 1:1 to ulimorelin or metoclopramide for 5 days. EFI was diagnosed by a gastric residual volume (GRV) ≥ 500 ml. A volume-based feeding protocol was employed, and enteral formulas were standardized. The primary end point was the percentage daily protein prescription (%DPP) received by patients over 5 days of treatment. Secondary end points included feeding success, defined as 80% DPP; gastric emptying, assessed by paracetamol absorption; incidences of recurrent intolerance (GRV ≥ 500 ml); vomiting or regurgitation; aspiration, defined by positive tracheal aspirates for pepsin; and pulmonary infection.

RESULTS

One hundred twenty patients were randomized and received the study drug (ulimorelin 62, metoclopramide 58). Mean APACHE II and SOFA scores were 21.6 and 8.6, and 63.3% of patients had medical reasons for ICU admission. Ulimorelin and metoclopramide resulted in comparable %DPPs over 5 days of treatment (median [Q1, Q3]: 82.9% [38.4%, 100.2%] and 82.3% [65.6%, 100.2%], respectively, p = 0.49). Five-day rates of feeding success were 67.7% and 70.6% when terminations unrelated to feeding were excluded, and there were no differences in any secondary outcomes or adverse events between the two groups.

CONCLUSIONS

Both prokinetic agents achieved similar rates of feeding success, and no safety differences between the two treatment groups were observed.

Rapid Detection of Methicillin-Resistant Staphylococcus aureus in BAL: A Pilot Randomized Controlled Trial

BACKGROUND

Guidelines recommend empirical vancomycin or linezolid for patients with suspected pneumonia at risk for methicillin-resistant Staphylococcus aureus (MRSA). Unneeded vancomycin or linezolid use may unnecessarily alter host flora and expose patients to toxicity. We therefore sought to determine if rapid testing for MRSA in BAL can safely decrease use of vancomycin or linezolid for suspected MRSA pneumonia.

METHODS

Operating characteristics of the assay were initially validated against culture on residual BAL. A prospective, unblinded, randomized clinical trial to assess the effect of antibiotic management made on the basis of rapid diagnostic testing (RDT) compared with usual care was subsequently conducted, with primary outcome of duration of vancomycin or linezolid administration. Secondary end points focused on safety.

RESULTS

Sensitivity of RPCR was 95.7%, with a negative likelihood ratio of 0.04 for MRSA. The clinical trial randomized 45 patients: 22 to antibiotic management made on the basis of RDT and 23 to usual care. Duration of vancomycin or linezolid administration was significantly reduced in the intervention group (32 h [interquartile range, 22-48] vs 72 h [interquartile range, 50-113], P < .001). Proportions with complications and length of stay trended lower in the intervention group. Hospital mortality was 13.6% in the intervention group and 39.1% for usual care (95% CI of difference, -3.3 to 50.3, P = .06). Standardized mortality ratio was 0.48 for the intervention group and 1.18 for usual care.

CONCLUSIONS

A highly sensitive BAL RDT for MRSA significantly reduced use of vancomycin and linezolid in ventilated patients with suspected pneumonia. Management made on the basis of RDT had no adverse effects, with a trend to lower hospital mortality.

TRIAL REGISTRY

ClinicalTrials.gov; No. NCT02660554; URL: www.clinicaltrials.gov.

Metagenomic comparison of tracheal aspirate and mini-bronchial alveolar lavage for assessment of respiratory microbiota

Accurate and informative microbiological testing is essential for guiding diagnosis and management of pneumonia in patients who are critically ill. Sampling of tracheal aspirate (TA) is less invasive compared with mini-bronchoalveolar lavage (mBAL) and is now recommended as a frontline diagnostic approach in patients who are mechanically ventilated, despite the historical belief that TA was suboptimal due to contamination from oral microbes. Advancements in metagenomic next-generation sequencing (mNGS) now permit assessment of airway microbiota without a need for culture and, as such, provide an opportunity to examine differences between mBAL and TA at a resolution previously unachievable. Here, we engaged shotgun mNGS to assess quantitatively the airway microbiome in matched mBAL and TA specimens from a prospective cohort of critically ill adults. We observed moderate differences between sample types across all subjects; however, we found significant compositional similarity in subjects with bacterial pneumonia, whose microbial communities were characterized by dominant pathogens. In contrast, in patients with noninfectious acute respiratory illnesses, significant differences were observed between sample types. Our findings suggest that TA sampling provides a similar assessment of airway microbiota as more invasive testing by mBAL in patients with pneumonia.

Are tracheal surveillance cultures useful in the intensive care unit?

Endotracheal aspirate (ETA) surveillance cultures have been used to predict the microorganisms responsible for ventilator associated pneumonia (VAP) in intensive care unit (ICU) patients for 3 decades. However, although more than a dozen studies have been performed, the usefulness and the safety of this strategy are still debated. Tracheobronchial bacterial colonization often precedes the occurrence of VAP, and it has been postulated that the microbes present in the tracheal secretions a few days before VAP might be the same as those retrieved in the lower respiratory tract. A large number of studies, with heterogeneous designs and variable results, have questioned the possibility of predicting, by regular ETA cultures after the 48^th hour of mechanical ventilation (MV), the microbiology of VAP and therefore of determining the adequate antibiotic therapy to limit the over-prescription of broad spectrum molecules when following guidelines. Although it has shown some promising results, the strategy has not achieved unanimity because of some discordant data. The aim of this review is to provide an updated overview of the literature available in the field and to attempt to determine the strengths and weaknesses of antibiotic stewardship based on ETA surveillance cultures in VAP, particularly in the global context of drug resistant microorganism emergence and the crucial necessity of broad spectrum molecule preservation.

Appraisal of systemic inflammation and diagnostic markers in a porcine model of VAP: secondary analysis from a study on novel preventive strategies

Background

We previously evaluated the efficacy of a ventilatory strategy to achieve expiratory flow bias and positive end-expiratory pressure (EFB + PEEP) or the Trendelenburg position (TP) for the prevention of ventilator-associated pneumonia (VAP). These preventive measures were aimed at improving mucus clearance and reducing pulmonary aspiration of bacteria-laden oropharyngeal secretions. This secondary analysis is aimed at evaluating the effects of aforementioned interventions on systemic inflammation and to substantiate the value of clinical parameters and cytokines in the diagnosis of VAP.

Methods

Twenty female pigs were randomized to be positioned in the semirecumbent/prone position, and ventilated with duty cycle 0.33 and without PEEP (control); positioned as in the control group, PEEP 5 cmH₂O, and duty cycle to achieve expiratory flow bias (EFB+PEEP); ventilated as in the control group, but in the Trendelenburg position (Trendelenburg). Following randomization, P. aeruginosa was instilled into the oropharynx. Systemic cytokines and tracheal secretions P. aeruginosa concentration were quantified every 24h. Lung biopsies were collected for microbiological confirmation of VAP.

Results

In the control, EFB + PEEP, and Trendelenburg groups, lung tissue Pseudomonas aeruginosa concentration was 2.4 ± 1.5, 1.9 ± 2.1, and 0.3 ± 0.6 log cfu/mL, respectively (p = 0.020). Whereas, it was 2.4 ± 1.9 and 0.6 ± 0.9 log cfu/mL in animals with or without VAP (p < 0.001). Lower levels of interleukin (IL)-1β (p = 0.021), IL-1RA (p < 0.001), IL-4 (p = 0.005), IL-8 (p = 0.008), and IL-18 (p = 0.050) were found in Trendelenburg animals. VAP increased IL-10 (p = 0.035), tumor necrosis factor-α (p = 0.041), and endotracheal aspirate (ETA) P. aeruginosa concentration (p = 0.024). A model comprising ETA bacterial burden, IL-10, and TNF-α yielded moderate discrimination for the diagnosis of VAP (area of the receiver operating curve 0.82, 95% CI 0.61–1.00).

Conclusions

Our findings demonstrate anti-inflammatory effects associated with the Trendelenburg position. In this reliable model of VAP, ETA culture showed good diagnostic accuracy, whereas systemic IL-10 and TNF-α marginally improved accuracy. Further clinical studies will be necessary to confirm clinical value of the Trendelenburg position as a measure to hinder inflammation during mechanical ventilation and significance of systemic IL-10 and TNF-α in the diagnosis of VAP.

The use of bronchoscopy in critically ill patients: considerations and complications

INTRODUCTION

Flexible bronchoscopy has been well established for diagnostic and therapeutic purposes in critically ill patients. Areas covered: This review outlines the clinical evidence of the utility and safety of flexible bronchoscopy in the intensive care unit, as well as specific considerations, including practical points and potential complications, in critically ill patients. Expert commentary: Its ease to learn and perform and its capacity for bedside application with relatively few complications make flexible bronchoscopy an indispensable tool in the intensive care unit setting. The main indications for flexible bronchoscopy in the intensive care unit are the visualization of the airways, sampling for diagnostic purposes and management of the artificial airways. The decision to perform flexible bronchoscopy can only be made by trade-offs between potential risks and benefits because of the fragile nature of the critically ill. Flexible bronchoscopy-associated serious adverse events are inevitable in cases of a lack of expertise or appropriate precautions.

Respiratory Microbiome Profiling for Etiologic Diagnosis of Pneumonia in Mechanically Ventilated Patients

Etiologic diagnosis of bacterial pneumonia relies on identification of causative pathogens by cultures, which require extended incubation periods and have limited sensitivity. Next-generation sequencing of microbial DNA directly from patient samples may improve diagnostic accuracy for guiding antibiotic prescriptions. In this study, we hypothesized that enhanced pathogen detection using sequencing can improve upon culture-based diagnosis and that certain sequencing profiles correlate with host response. We prospectively collected endotracheal aspirates and plasma within 72 h of intubation from patients with acute respiratory failure. We performed 16S rRNA gene sequencing to determine pathogen abundance in lung samples and measured plasma biomarkers to assess host responses to detected pathogens. Among 56 patients, 12 patients (21%) had positive respiratory cultures. Sequencing revealed lung communities with low diversity (p < 0.02) dominated by taxa (>50% relative abundance) corresponding to clinically isolated pathogens (concordance p = 0.009). Importantly, sequencing detected dominant pathogens in 20% of the culture-negative patients exposed to broad-spectrum empiric antibiotics. Regardless of culture results, pathogen dominance correlated with increased plasma markers of host injury (receptor of advanced glycation end-products-RAGE) and inflammation (interleukin-6, tumor necrosis factor receptor 1-TNFR1) (p < 0.05), compared to subjects without dominant pathogens in their lung communities. Machine-learning algorithms identified pathogen abundance by sequencing as the most informative predictor of culture positivity. Thus, enhanced detection of pathogenic bacteria by sequencing improves etiologic diagnosis of pneumonia, correlates with host responses, and offers substantial opportunity for individualized therapeutic targeting and antimicrobial stewardship. Clinical translation will require validation with rapid whole meta-genome sequencing approaches to guide real-time antibiotic prescriptions.

Sequelae of Index Complications following Inpatient Head and Neck Surgery: Characterizing Secondary Complications

Objective To characterize patterns of secondary complications after inpatient head and neck surgery. Study Design Retrospective cohort study. Setting National Surgical Quality Improvement Program (2005-2015). Subjects and Methods We identified 18,584 patients who underwent inpatient otolaryngologic surgery. Four index complications were studied: pneumonia, bleeding or transfusion event (BTE), deep/organ space surgical site infection (SSI), and myocardial infarction (MI). Each patient with an index complication was matched to a control patient based on propensity for the index event and event-free days. Rates of 30-day secondary complications and mortality were compared. Results Index pneumonia (n = 254) was associated with several complications, including reintubation (odds ratio [OR], 11.7; 95% confidence interval [CI], 5.2-26.4), sepsis (OR, 8.8; 95% CI, 4.5-17.2), and death (OR, 5.3; 95% CI, 1.9-14.9). Index MI (n = 50) was associated with increased odds of reintubation (OR, 17.2; 95% CI, 3.5-84.1), ventilatory failure (OR, 5.8; 95% CI, 1.8-19.1), and death (OR, 24.8; 95% CI, 2.9-211.4). Index deep/organ space SSI (n = 271) was associated with dehiscence (OR, 7.2; 95% CI, 3.6-14.2) and sepsis (OR, 38.3; 95% CI, 11.6-126.4). Index BTE (n = 1009) increased the odds of cardiac arrest (OR, 3.9; 95% CI, 1.8-8.5) and death (OR, 2.9; 95% CI, 1.6-5.1). Conclusions Our study is the first to quantify the effect of index complications on the risk of specific secondary complications following inpatient head and neck surgery. These associations may be used to identify patients most at risk postoperatively and target specific interventions aimed to prevent or interrupt further complications.

Ventilator-associated events after cardiac surgery: evidence from 1,709 patients

Background

Ventilator-associated event (VAE) is a new surveillance for nosocomial infections in mechanically ventilated patients. To date, little is known about VAEs after cardiac surgeries. The present study firstly focused on patients who have undergone heart operations, intending to draw a comprehensive description of VAEs.

Methods

Postoperative patients from September 2012 to December 2015 were monitored for VAEs. By reviewing electronic medical records and preserved files retrospectively, clinical data were further analyzed.

Results

A total of 1,709 adult patients were enrolled, of which 166 episodes met the criteria for VAE. The mean incidence rate reached up to 9.7% and 49.9 per 1,000 mechanical ventilation days. By using both univariate analysis and multiple logistic regression analysis, chronic obstructive pulmonary disease (COPD), left ventricle ejection fraction (LVEF) <30%, cardiopulmonary bypass time, aortic clamping time, mechanical ventilation time, reintubation, dosage of blood products and acute kidney injury (AKI) were found to be risk factors for VAEs. Compared with non-VAE group, VAEs were closely related to higher mortality, longer intensive care unit stay time and hospitalization time. In addition, 91 strains of pathogens were isolated from endotracheal aspirates of 81 patients with VAE, of which Pseudomonas aeruginosa was the most common pathogenic microorganism (30 isolates, 37.0%), followed by Acinetobacter baumannii (27 isolates, 33.3%) and other five types.

Conclusions

VAE algorithm is a valid and reliable surveillance for possible infections caused by mechanical ventilation, which could easily occur in patients after cardiac surgery and is associated with poor prognosis. The risks and pathogens that we have investigated will provide potential preventive strategies.

Pneumonia

The chapter will begin with an overview of pathological-clinical correlates in pneumonia, and of the principles of diagnosis and treatment that can be broadly applied to all pneumonias. Thereafter, community-acquired pneumonia, hospital-acquired and ventilator-associated pneumonia, and aspiration pneumonia will be considered separately, considering aspects of management specifically relevant to each. The chapter will end by discussing preventive strategies, and with a brief outline of future challenges for the management of pneumonia.

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.

Diagnostic Value of Endotracheal Aspirates Sonication on Ventilator-Associated Pneumonia Microbiologic Diagnosis

Microorganisms are able to form biofilms within respiratory secretions. Methods to disaggregate such biofilms before utilizing standard, rapid, or high throughput diagnostic technologies may aid in pathogen detection during ventilator associated pneumonia (VAP) diagnosis. Our aim was to determine if sonication of endotracheal aspirates (ETA) would increase the sensitivity of qualitative, semi-quantitative, and quantitative bacterial cultures in an animal model of pneumonia caused by Pseudomonas aeruginosa or by methicillin resistant Staphylococcus aureus (MRSA). Material and methods: P. aeruginosa or MRSA was instilled into the lungs or the oropharynx of pigs in order to induce severe VAP. Time point assessments for qualitative and quantitative bacterial cultures of ETA and bronchoalveolar lavage (BAL) samples were performed at 24, 48, and 72 h after bacterial instillation. In addition, at 72 h (autopsy), lung tissue was harvested to perform quantitative bacterial cultures. Each ETA sample was microbiologically processed with and without applying sonication for 5 min at 40 KHz before bacterial cultures. Sensitivity and specificity were determined using BAL as a gold-standard. Correlation with BAL and lung bacterial burden was also determined before and after sonication. Assessment of biofilm clusters and planktonic bacteria was performed through both optical microscopy utilizing Gram staining and Confocal Laser Scanning Microscopy utilizing the LIVE/DEAD^®BacLight kit. Results: 33 pigs were included, 27 and 6 from P. aeruginosa and MRSA pneumonia models, respectively. Overall, we obtained 85 ETA, 69 (81.2%) from P. aeruginosa and 16 (18.8%) from MRSA challenged pigs. Qualitative cultures did not significantly change after sonication, whereas quantitative ETA cultures did significantly increase bacterial counting. Indeed, sonication consistently increased bacterial burden in ETAs at 24, 48, and 72 h after bacterial challenge. Sonication also improved sensitivity of ETA quantitative cultures and maintained specificity at levels previously reported and accepted for VAP diagnosis. Conclusion: The use of sonication in ETA respiratory samples needs to be clinically validated since sonication could potentially improve pathogen detection before standard, rapid, or high throughput diagnostic methods used in routine microbial diagnostics.

Controversies and advances in the management of ventilator associated pneumonia

INTRODUCTION

Although national surveillance data suggests that the incidence of ventilator associated pneumonia (VAP) is down-trending, it remains one of the most commonly encountered hospital acquired infections in the United States and worldwide. Its association with increased healthcare costs and worsened patient outcomes warrants continued effort to improve the care of patients with VAP. Areas covered: The increasing prevalence of multi-drug resistant bacteria further drives the need to explore advances in diagnostic and treatment options. In this review, controversies pertaining to the definition and diagnosis of VAP as well as empiric treatment strategies will be discussed along with several developments related to rapid microbiologic testing methods and the use of non-traditional antimicrobial agents. Expert commentary: The application of rapid diagnostic techniques to identify microbial pathogens is perhaps one of the most impactful advancements in the treatment of serious nosocomial infections. This technology has the potential to reduce inappropriate initial antimicrobial therapy, unnecessary antimicrobial exposure, and mortality in patients with VAP. In addition, the anticipated approval of new antimicrobial agents within the next several years will provide a much-needed expansion of available treatment options in an era of growing antimicrobial resistance.

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.

Update on childhood and adult infectious tracheitis

The trachea is a pivotal organ of the respiratory tract. Rather than a genuine anatomic border, it acts as a crossroad in all respiratory infectious processes. Even though not strictly limited to the trachea, infections such as laryngotracheitis and tracheobronchitis are frequently diagnosed in children, in particular during the winter season. Infectious tracheitis etiologies are diverse and the distinction between viral and bacterial origins, albeit difficult, remains relevant considering the substantial differences in terms of gravity and therapeutic management. This literature review summarizes the microbiological and clinical aspects of community-acquired and nosocomial tracheitis in adults and children, as well as the adequate diagnostic and therapeutic approaches. It also highlights the emergence of fungal tracheitis in immunocompromised patients, of ventilator-associated tracheitis in intensive care medicine, and beyond all that the potential short and long-term consequences of tracheitis.

Ventilator-Associated Pneumonia: The Role of Emerging Diagnostic Technologies

Antibiotic resistance has emerged as a key determinant of outcome in patients with serious infections along with the virulence of the underlying pathogen. Within the intensive care unit (ICU) setting, ventilator-associated pneumonia (VAP) is a common nosocomial infection that is frequently caused by multidrug-resistant bacteria. Antimicrobial resistance is a growing challenge in the care of critically ill patients. Escalating rates of antibiotic resistance add substantially to the morbidity, mortality, and cost related to infection in the ICU. Both gram-positive organisms, such as methicillin-resistant Staphylococcus aureus and vancomycin-intermediate S. aureus, and gram-negative bacteria, including Pseudomonas aeruginosa, Acinetobacter species, carbapenem-resistant Enterobacteriaceae, such as the Klebsiella pneumoniae carbapenemase-producing bacteria, and extended spectrum β-lactamase organisms, have contributed to the escalating rates of resistance seen in VAP and other nosocomial infections. The rising rates of antimicrobial resistance have led to the routine empiric administration of broad-spectrum antibiotics even when bacterial infection is not documented. Moreover, there are several new broader-spectrum antibiotics that have recently become available and others scheduled for approval in the near future. The challenge to ICU clinicians is how to most effectively utilize these agents to maximize patient benefits while minimizing further emergence of resistance. Use of rapid diagnostics may hold the key for achieving this important balance. There is an urgent need for integrating the administration of new and existing antibiotics with the emerging rapid diagnostic technologies in a way that is both cost-effective and sustainable for the long run.

Biomarkers kinetics in the assessment of ventilator-associated pneumonia response to antibiotics - results from the BioVAP study

PURPOSE

Our aim was to evaluate the role of biomarker kinetics in the assessment of ventilator-associated pneumonia (VAP) response to antibiotics.

MATERIALS AND METHODS

We performed a prospective, multicenter, observational study to evaluate in 37 microbiologically documented VAP, the kinetics of C-reactive protein (CRP), procalcitonin (PCT), mid-region fragment of pro-adrenomedullin (MR-proADM). The kinetics of each variable, from day 1 to 6 of therapy, was assessed with a time dependent analysis comparing survivors and non-survivors.

RESULTS

During the study period kinetics of CRP as well as its relative changes, CRP-ratio, was significantly different between survivors and non-survivors (p=0.026 and p=0.005, respectively). On day 4 of antibiotic therapy, CRP of survivors was 47% of the initial value while it was 96% in non-survivors. The kinetics of other studied variables did not distinguish between survivors and non-survivors. In survivors the bacterial load also decreased markedly. Adequate initial antibiotic therapy was associated with lower mortality (p=0.025) and faster CRP decrease (p=0.029).

CONCLUSIONS

C-reactive protein kinetics can be used to identify VAP patients with poor outcome as soon as four days after the initiation of treatment. (Trial registration - NCT02078999; registered 3 August 2012).

The efficacy of bedside chest ultrasound: from accuracy to outcomes

For many respiratory physicians, point-of-care chest ultrasound is now an integral part of clinical practice. The diagnostic accuracy of ultrasound to detect abnormalities of the pleura, the lung parenchyma and the thoracic musculoskeletal system is well described. However, the efficacy of a test extends beyond just diagnostic accuracy. The true value of a test depends on the degree to which diagnostic accuracy efficacy influences decision-making efficacy, and the subsequent extent to which this impacts health outcome efficacy. We therefore reviewed the demonstrable levels of test efficacy for bedside ultrasound of the pleura, lung parenchyma and thoracic musculoskeletal system.For bedside ultrasound of the pleura, there is evidence supporting diagnostic accuracy efficacy, decision-making efficacy and health outcome efficacy, predominantly in guiding pleural interventions. For the lung parenchyma, chest ultrasound has an impact on diagnostic accuracy and decision-making for patients presenting with acute respiratory failure or breathlessness, but there are no data as yet on actual health outcomes. For ultrasound of the thoracic musculoskeletal system, there is robust evidence only for diagnostic accuracy efficacy.We therefore outline avenues to further validate bedside chest ultrasound beyond diagnostic accuracy, with an emphasis on confirming enhanced health outcomes.

Management of infections associated with neurocritical care

The reported incidence of hospital-acquired infections (HAIs) in the neurointensive care unit (NICU) ranges from 20% to 30%. HAIs in US hospitals cost between $28 and $45 billion per year in direct medical costs. These infections are associated with increased length of hospital stay and increased morbidity and mortality. Infection risk is increased in NICU patients due to medication side-effects, catheter and line placement, neurosurgical procedures, and acquired immune suppression secondary to steroid/barbiturate use and brain injury itself. Some of these infections may be preventable but many are not. Their appearance do not always constitute a failure of prevention or physician error. Neurointensivists require indepth knowledge of common nosocomial infections, their diagnosis and treatment, and an approach to evidence-based practices that improve processes of care and reduce HAIs.

Pneumonia

Pneumonia is an important cause of morbidity and mortality globally. It is the leading cause of death in infants and young children with the majority of these deaths occurring in low income countries. Risk factors affecting incidence and outcome include extremes of age, poor nutrition, immunosuppression, environmental exposures and socioeconomic determinants. Pneumonia can be caused by a wide range of pathogens including bacteria, viruses and fungi, and the etiology varies by epidemiological setting, comorbidities and whether the pneumonia is community-acquired or hospital-acquired. Streptococcus pneumoniae is the major cause of community-acquired bacterial pneumonia while Gram negative bacteria, often resistant to multiple antibiotics, are common causes of hospital-acquired pneumonia and pneumonia in immunosuppressed individuals. Diagnosis is generally clinical and management is based mainly on knowledge of likely causative pathogens as well as clinical severity and presence of known risk factors. Timely and effective antibiotic treatment and oxygen therapy if hypoxemic are critical to patient outcomes. Preventive measures range from improved nutrition and hygiene to specific vaccines that target common causes in children and adults such as the pneumococcal or influenza vaccines.

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.

Use of Tracheal Aspirate Culture in Newly Intubated Patients with Community-Onset Pneumonia

RATIONALE

Successful treatment of life-threatening community-acquired pneumonia requires appropriate empiric antibiotic coverage. But using conventional diagnostic techniques, a microbiological diagnosis is often not achieved. The diagnostic usefulness of tracheal aspirate at the time of intubation in patients with severe pneumonia has not been well studied.

OBJECTIVES

The purpose of this study was to evaluate the use of tracheal aspirate culture in identifying pneumonia pathogens.

METHODS

We identified all patients older than 18 years of age with International Classification of Disease, Ninth Revision codes and radiographic evidence of pneumonia seen in the emergency departments at 2 university-affiliated Utah hospitals from December 2009 to November 2010 and from December 2011 to November 2012. Patients intubated within 24 hours of arrival were then identified electronically. Postintubation orders instructed respiratory therapists to obtain tracheal aspirate for culture. All culture results were reviewed individually and defined as positive if a pneumonia pathogen was identified. Results of other microbiology studies were obtained from the electronic medical record.

MEASUREMENTS AND MAIN RESULTS

Of 2,011 patients with pneumonia, 94 were intubated and 84 had a tracheal aspirate obtained. Of these 84 patients, 47 (56%) had a pulmonary pathogen identified by tracheal aspirate culture, 80 also had blood cultures, and 71 underwent Pneumococcal and Legionella urinary antigen testing. A microbiological diagnosis was made in 55 patients (65.5%) by any diagnostic method. In 39% of patients (32 of 82), the tracheal aspirate culture was the only positive test, resulting in a unique microbiological diagnosis in patients who would have otherwise been classified as "culture negative."

CONCLUSIONS

Tracheal aspirate cultures obtained as part of routine care identified a plausible pneumonia pathogen in more than one-half of emergency department adult patients with severe pneumonia requiring intubation. Tracheal aspirate culture offers important additive diagnostic value to other routine tests.

Infectious complications after out-of-hospital cardiac arrest-A comparison between two target temperatures

BACKGROUND

It has been suggested that target temperature management (TTM) increases the probability of infectious complications after cardiac arrest. We aimed to compare the incidence of pneumonia, severe sepsis and septic shock after out-of-hospital cardiac arrest (OHCA) in patients with two target temperatures and to describe changes in biomarkers and possible mortality associated with these infectious complications.

METHODS

Post-hoc analysis of the TTM-trial which randomized patients resuscitated from OHCA to a target temperature of 33°C or 36°C. Prospective data on infectious complications were recorded daily during the ICU-stay. Pneumonia, severe sepsis and septic shock were considered infectious complications. Procalcitonin (PCT) and C-reactive-protein (CRP) levels were measured at 24h, 48h and 72h after cardiac arrest.

RESULTS

There were 939 patients in the modified intention-to-treat population. Five-hundred patients (53%) developed pneumonia, severe sepsis or septic shock which was associated with mortality in multivariate analysis (Hazard ratio [HR] 1.39; 95%CI 1.13-1.70; p=0.001). There was no statistically significant difference in the incidence of infectious complications between temperature groups (sub-distribution hazard ratio [SHR] 0.88; 95%CI 0.75-1.03; p=0.12). PCT and CRP were significantly higher for patients with infections at all times (p<0.001), but there was considerable overlap.

CONCLUSIONS

Patients who develop pneumonia, severe sepsis or septic shock after OHCA might have an increased mortality. A target temperature of 33°C after OHCA was not associated with an increased risk of infectious complications compared to a target temperature of 36°C. PCT and CRP are of limited value for diagnosing infectious complications after cardiac arrest.

Quality of the aetiological diagnosis of ventilator-associated pneumonia in Spain in the opinion of intensive care specialists and microbiologists

INTRODUCTION

Current guidelines for the microbiological diagnosis of ventilator-associated pneumonia (VAP) are imprecise. Based on data provided by intensive care specialists (ICS) and microbiologists, this study defines the clinical practices and microbiological techniques currently used for an aetiological diagnosis of VAP and pinpoints deficiencies.

METHODS

Eighty hospitals in the national health network with intensive care and microbiology departments were sent two questionnaires, one for each department, in order to collect data on VAP diagnosis for the previous year.

RESULTS

Out of the 80 hospitals, 35 (43.8%) hospitals participated. These included 673 ICU beds, 32,020 ICU admissions, 173,820 ICU days stay, and generated 27,048 lower respiratory tract specimens in the year. A third of the hospitals (35%) had a microbiology department available 24/7. Most samples (83%) were tracheal aspirates. Gram stain results were immediately reported in around half (47%) of the hospitals. Quantification was made in 75% of hospitals. Molecular techniques and direct susceptibility testing were performed in 12% and one institution, respectively. Mean turnaround time for a microbiological report was 1.7 (SD; 0.7), and 2.2 (SD; 0.6) days for a negative and positive result, respectively. Telephone/in-person information was offered by 65% of the hospitals. Most (89%) ICS considered microbiological information as very useful. No written procedures were available in half the ICUs.

CONCLUSIONS

Both ICS and microbiologists agreed that present guidelines for the diagnosis of VAP could be much improved, and that a new set of consensus guidelines is urgently required. A need for guidelines to be more effectively implemented was also identified in order to improve outcomes in patients with VAP.

Characteristics, Clinical Relevance, and the Role of Echinocandins in Fungal-Bacterial Interactions

Fungal-bacterial interactions are common in the environment. The interactions between invasive fungi (eg, Candida species and Aspergillus species) and pathogenic bacteria can be particularly significant in the outcome of human infections. Study of these interactions in vivo using murine or invertebrate models, such as Caenorhabditis elegans or Galleria mellonella, has been very helpful in increasing our understanding of the pathogenesis of mixed infections and in identifying ways to use this between-kingdom interplay to our advantage. Based on their effect against fungal biofilms and their immunomodulatory properties, the newer class of antifungal agents, known as echinocandins, has the potential to be useful in polymicrobial infections and in high-risk complex infections such as ventilator-associated pneumonia or sepsis where colonization by fungi can lead to worse outcomes.

Antibiotic Utilization Patterns in Patients with Ventilator-Associated Pneumonia: A Canadian Context

This retrospective cohort study describes the patterns of antibiotic use for the treatment of ventilator-associated pneumonia (VAP) in the Calgary Zone of Alberta Health Services. Timing, appropriateness, and duration of antibiotics were evaluated in two hundred consecutive cases of VAP derived from 4 adult intensive care units (ICU). Antibiotic therapy was initiated in less than 24 hours from VAP diagnosis in 83% of cases. Although most patients (89%) received empiric therapy that demonstrated in vitro sensitivity to the identified pathogens, only 24% of cases were congruent with the 2008 Association of Medical Microbiology and Infectious Disease (AMMI) guidelines. Both ICU (p = 0.001) and hospital (p = 0.015) mortality were significantly lower and there was a trend for shorter ICU length of stay (p = 0.051) in patients who received appropriate versus inappropriate initial antibiotics. There were no outcome differences related to compliance with AMMI guidelines. This exploratory study provides insight into the use of antimicrobials for the treatment of VAP in a large Canadian health region. The discordance between the assessments of appropriateness of empiric therapy based on recovered pathogens versus AMMI guidelines is notable, emphasizing the importance of using as much as possible local microbiologic and antimicrobial resistance data.

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.

Clinical Correlates of Surveillance Events Detected by National Healthcare Safety Network Pneumonia and Lower Respiratory Infection Definitions-Pennsylvania, 2011-2012

OBJECTIVE To determine the clinical diagnoses associated with the National Healthcare Safety Network (NHSN) pneumonia (PNEU) or lower respiratory infection (LRI) surveillance events DESIGN Retrospective chart review SETTING A convenience sample of 8 acute-care hospitals in Pennsylvania PATIENTS All patients hospitalized during 2011-2012 METHODS Medical records were reviewed from a random sample of patients reported to the NHSN to have PNEU or LRI, excluding adults with ventilator-associated PNEU. Documented clinical diagnoses corresponding temporally to the PNEU and LRI events were recorded. RESULTS We reviewed 250 (30%) of 838 eligible PNEU and LRI events reported to the NHSN; 29 reported events (12%) fulfilled neither PNEU nor LRI case criteria. Differences interpreting radiology reports accounted for most misclassifications. Of 81 PNEU events in adults not on mechanical ventilation, 84% had clinician-diagnosed pneumonia; of these, 25% were attributed to aspiration. Of 43 adult LRI, 88% were in mechanically ventilated patients and 35% had no corresponding clinical diagnosis (infectious or noninfectious) documented at the time of LRI. Of 36 pediatric PNEU events, 72% were ventilator associated, and 70% corresponded to a clinical pneumonia diagnosis. Of 61 pediatric LRI patients, 84% were mechanically ventilated and 21% had no corresponding clinical diagnosis documented. CONCLUSIONS In adults not on mechanical ventilation and in children, most NHSN-defined PNEU events corresponded with compatible clinical conditions documented in the medical record. In contrast, NHSN LRI events often did not. As a result, substantial modifications to the LRI definitions were implemented in 2015. Infect Control Hosp Epidemiol 2016;37:818-824.

The effect of using blood culture bottle of bronchoalveolar larvage fluid in pneumonia

BACKGROUND

Pneumonia is a primary cause of morbidity and mortality in infectious disease, and increasing antimicrobial resistance has raised concerns of treatment failure. Therefore, we evaluated the value of a blood culture bottle for bronchoalveolar lavage (BAL) samples on pathogen identification and on treatment modification in patients with pneumonia.

METHODS

We conducted a prospective study and enrolled 39 patients who were hospitalized for pneumonia. Enrolled patients underwent BAL; a 10-ml aliquot was transferred to a sterile container for standard quantitative culture, and a 5 ml aliquot was transferred to both an aerobic and an anaerobic blood culture bottle.

RESULTS

Microbes were detected in all 39 (100 %) specimens and possible pathogens were identified in 34 patients (84.6 %) from BAL blood culture bottles. In contrast, microbes were detected in 10 patients (25.6 %) and possible pathogens were isolated in 8 patients (20.5 %) in BAL fluid using conventional culture methods. Finally, 8 of 39 (20.5 %) patients changed antibiotics according to the BAL blood culture results and pneumonia improved in 6 of these patients.

CONCLUSIONS

Using blood culture bottles for BAL sampling in patients with pneumonia is a sensitive method to detect pathogens in order to identify an adequate antibiotic treatment regimen.

Reactive oxygen species measure for rapid detection of infection in fluids

BACKGROUND

Early detection of infection is critical to rapidly starting effective treatment. Diagnosis can be difficult, particularly in the intensive care unit (ICU) population. Because the presence of polymorphonuclear neutrophils in tissues is the hallmark of inflammatory processes, the objective of this proof of concept study was to determine whether the measurement of reactive oxygen species (ROS) could be an efficient diagnostic tool to rapidly diagnose infections in peritoneal, pleural and bronchoalveolar lavage (BAL) fluids in ICU patients.

METHODS

We prospectively included all patients hospitalized in the 21-bed surgical ICU of a teaching hospital from June 2010 to February 2014 who presented with systemic inflammatory response syndrome with suspicion of a peritoneal or pleural fluid or pulmonary infection needing a BAL. Instantaneous basal ROS production was measured in fluids and after phorbol 12-myristate 13-acetate (PMA) stimulation. We compared patients with infected fluids to those with non-infected fluids.

RESULTS

The overall ICU mortality rate was 34 %. A majority of patients were sampled following a delay of 5 days (2-12) after ICU admission, with most receiving antibiotics at the time of fluid sampling (71 %). Fluids were infected in 21/65 samples: 6/17 peritoneal fluids, 8/28 pleural fluids and 7/20 BALs. ROS production was significantly higher in the infected than in the non-infected group at baseline and after PMA stimulation in the peritoneal and pleural fluids but not in BAL.

CONCLUSION

Assessing instantaneous ROS production appears as a fast and reliable diagnostic method for detecting peritoneal and pleural fluid infection.

Characteristics and outcomes of anti-infective de-escalation during health care-associated intra-abdominal infections

Background

De-escalation is strongly recommended for antibiotic stewardship. No studies have addressed this issue in the context of health care-associated intra-abdominal infections (HCIAI). We analyzed the factors that could interfere with this process and their clinical consequences in intensive care unit (ICU) patients with HCIAI.

Methods

All consecutive patients admitted for the management of HCIAI who survived more than 3 days following their diagnosis, who remained in the ICU for more than 3 days, and who did not undergo early reoperation during the first 3 days were analyzed prospectively in an observational, single-center study in a tertiary care university hospital.

Results

Overall, 311 patients with HCIAI were admitted to the ICU. De-escalation was applied in 110 patients (53 %), and no de-escalation was reported in 96 patients (47 %) (escalation in 65 [32 %] and unchanged regimen in 31 [15 %]). Lower proportions of Enterococcus faecium, nonfermenting Gram-negative bacilli (NFGNB), and multidrug-resistant (MDR) strains were cultured in the de-escalation group. No clinical difference was observed at day 7 between patients who were de-escalated and those who were not. Determinants of de-escalation in multivariate analysis were adequate empiric therapy (OR 9.60, 95 % CI 4.02–22.97) and empiric use of vancomycin (OR 3.39, 95 % CI 1.46–7.87), carbapenems (OR 2.64, 95 % CI 1.01–6.91), and aminoglycosides (OR 2.31 95 % CI 1.08–4.94). The presence of NFGNB (OR 0.28, 95 % CI 0.09–0.89) and the presence of MDR bacteria (OR 0.21, 95 % CI 0.09–0.52) were risk factors for non-de-escalation. De-escalation did not change the overall duration of therapy. The risk factors for death at day 28 were presence of fungi (HR 2.64, 95 % CI 1.34–5.17), Sequential Organ Failure Assessment score on admission (HR 1.29, 95 % CI 1.16–1.42), and age (HR 1.03, 95 % CI 1.01–1.05). The survival rate expressed by a Kaplan-Meier curve was similar between groups (log-rank test p value 0.176).

Conclusions

De-escalation is a feasible option in patients with polymicrobial infections such as HCIAI, but MDR organisms and NFGNB limit its implementation.

Optimizing the Use of Antibacterial Agents in the Neonatal Period

Antibiotics are invaluable in the management of neonatal infections. However, overuse or misuse of antibiotics in neonates has been associated with adverse outcomes, including increased risk for future infection, necrotizing enterocolitis, and mortality. Strategies to optimize the use of antibiotics in the neonatal intensive care unit include practicing effective infection prevention, improving the diagnostic evaluation and empiric therapy for suspected infections, timely adjustment of therapy as additional information becomes available, and treating proven infections with an effective, narrow-spectrum agent for the minimum effective duration. Antibiotic stewardship programs provide support for these strategies but require the participation and input of neonatologists as stakeholders to be most effective.

Composition and dynamics of the respiratory tract microbiome in intubated patients

BACKGROUND

Lower respiratory tract infection (LRTI) is a major contributor to respiratory failure requiring intubation and mechanical ventilation. LRTI also occurs during mechanical ventilation, increasing the morbidity and mortality of intubated patients. We sought to understand the dynamics of respiratory tract microbiota following intubation and the relationship between microbial community structure and infection.

RESULTS

We enrolled a cohort of 15 subjects with respiratory failure requiring intubation and mechanical ventilation from the medical intensive care unit at an academic medical center. Oropharyngeal (OP) and deep endotracheal (ET) secretions were sampled within 24 h of intubation and every 48-72 h thereafter. Bacterial community profiling was carried out by purifying DNA, PCR amplification of 16S ribosomal RNA (rRNA) gene sequences, deep sequencing, and bioinformatic community analysis. We compared enrolled subjects to a cohort of healthy subjects who had lower respiratory tract sampling by bronchoscopy. In contrast to the diverse upper respiratory tract and lower respiratory tract microbiota found in healthy controls, critically ill subjects had lower initial diversity at both sites. Diversity further diminished over time on the ventilator. In several subjects, the bacterial community was dominated by a single taxon over multiple time points. The clinical diagnosis of LRTI ascertained by chart review correlated with low community diversity and dominance of a single taxon. Dominant taxa matched clinical bacterial cultures where cultures were obtained and positive. In several cases, dominant taxa included bacteria not detected by culture, including Ureaplasma parvum and Enterococcus faecalis.

CONCLUSIONS

Longitudinal analysis of respiratory tract microbiota in critically ill patients provides insight into the pathogenesis and diagnosis of LRTI. 16S rRNA gene sequencing of endotracheal aspirate samples holds promise for expanded pathogen identification.

Twenty-Eight-Day Mortality of Blunt Traumatic Brain Injury and Co-Injuries Requiring Mechanical Ventilation

OBJECTIVE

This paper aims to assess the impact of co-injuries and consequent emergency surgical interventions and nosocomial pneumonia on the 28-day mortality of patients with severe traumatic brain injuries (TBIs).

SUBJECTS AND METHODS

One hundred and seventy-seven patients with TBI admitted to the emergency trauma intensive care unit at the Clinical Center of Serbia for more than 48 h were studied over a 1-year period. On admission, the Glasgow Coma Scale (GCS), Injury Severity Score (ISS) and Acute Physiology and Chronic Health Evaluation II score (APACHE II) were calculated. At admission, an isolated TBI was recorded in 45 of the patients, while 44 had three or more co-injuries.

RESULTS

Of the 177 patients, 78 (44.1%) died by the end of the 28-day follow-up period. They had a significantly higher ISS score (25 vs. 20; p = 0.024) and more severe head (p = 0.034) and chest (p = 0.013) injuries compared to those who survived. Nonsurvivors had spent more days on mechanical ventilation (9.5 vs. 8; p = 0.041) and had a significantly higher incidence of ventilator-associated pneumonia (VAP) than survivors (67.9 vs. 40.4%; p < 0.001). A high Rotterdam CT score (OR 2.062; p < 0.001) and a high APACHE II score (OR 1.219; p < 0.001) were identified as independent predictors of early TBI-related mortality.

CONCLUSION

Patients who had TBI with a high Rotterdam score and a high APACHE II score were at higher risk of 28-day mortality. VAP was a very common complication of TBI and was associated with an early death and higher mortality in the subgroup of patients with a GCS ≤8.

Lung Ultrasound for Early Diagnosis of Ventilator-Associated Pneumonia

BACKGROUND

Lung ultrasound (LUS) has been successfully applied for monitoring aeration in ventilator-associated pneumonia (VAP) and to diagnose and monitor community-acquired pneumonia. However, no scientific evidence is yet available on whether LUS reliably improves the diagnosis of VAP.

METHODS

In a multicenter prospective study of 99 patients with suspected VAP, we investigated the diagnostic performance of LUS findings of infection, subpleural consolidation, lobar consolidation, and dynamic arborescent/linear air bronchogram. We also evaluated the combination of LUS with direct microbiologic examination of endotracheal aspirates (EA). Scores for LUS findings and EA were analyzed in two ways. First, the clinical-LUS score (ventilator-associated pneumonia lung ultrasound score [VPLUS]) was calculated as follows: ≥ 2 areas with subpleural consolidations, 1 point; ≥ 1 area with dynamic arborescent/linear air bronchogram, 2 points; and purulent EA, 1 point. Second, the VPLUS-direct gram stain examination (EAgram) was scored as follows: ≥ 2 areas with subpleural consolidations, 1 point; ≥ 1 area with dynamic arborescent/linear air bronchogram, 2 points; purulent EA, 1 point; and positive direct gram stain EA examination, 2 points.

RESULTS

For the diagnosis of VAP, subpleural consolidation and dynamic arborescent/linear air bronchogram had a positive predictive value of 86% with a positive likelihood ratio of 2.8. Two dynamic linear/arborescent air bronchograms produced a positive predictive value of 94% with a positive likelihood ratio of 7.1. The area under the curve for VPLUS-EAgram and VPLUS were 0.832 and 0.743, respectively. VPLUS-EAgram ≥ 3 had 77% (58-90) specificity and 78% (65-88) sensitivity; VPLUS ≥ 2 had 69% (50-84) specificity and 71% (58-81) sensitivity.

CONCLUSIONS

By detecting ultrasound features of infection, LUS was a reliable tool for early VAP diagnosis at the bedside.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02244723; URL: www.clinicaltrials.gov.

Incidence of ventilator-associated pneumonia in Australasian intensive care units: use of a consensus-developed clinical surveillance checklist in a multisite prospective audit

OBJECTIVES

With disagreements on diagnostic criteria for ventilator-associated pneumonia (VAP) hampering efforts to monitor incidence and implement preventative strategies, the study objectives were to develop a checklist for clinical surveillance of VAP, and conduct an audit in Australian/New Zealand intensive care units (ICUs) using the checklist.

SETTING

Online survey software was used for checklist development. The prospective audit using the checklist was conducted in 10 ICUs in Australia and New Zealand.

PARTICIPANTS

Checklist development was conducted with members of a bi-national professional society for critical care physicians using a modified Delphi technique and survey. A 30-day audit of adult patients mechanically ventilated for >72 h.

PRIMARY AND SECONDARY OUTCOME MEASURES

Presence of items on the screening checklist; physician diagnosis of VAP, clinical characteristics, investigations, treatments and patient outcome.

RESULTS

A VAP checklist was developed with five items: decreasing gas exchange, sputum changes, chest X-ray infiltrates, inflammatory response, microbial growth. Of the 169 participants, 17% (n=29) demonstrated characteristics of VAP using the checklist. A similar proportion had an independent physician diagnosis (n=30), but in a different patient subset (only 17% of cases were identified by both methods). The VAP rate per 1000 mechanical ventilator days for the checklist and clinician diagnosis was 25.9 and 26.7, respectively. The item 'inflammatory response' was most associated with the first episode of physician-diagnosed VAP.

CONCLUSIONS

VAP rates using the checklist and physician diagnosis were similar to ranges reported internationally and in Australia. Of note, different patients were identified with VAP by the checklist and physicians. While the checklist items may assist in identifying patients at risk of developing VAP, and demonstrates synergy with the recently developed Centers for Disease Control (CDC) guidelines, decision-making processes by physicians when diagnosing VAP requires further exploration.

Clinical course and complications following diagnostic bronchoalveolar lavage in critically ill mechanically ventilated patients

Background

Flexible, fibreoptic bronchoscopy (FFB) and bronchoalveolar lavage (BAL) have been used for diagnostic purposes in critically ill ventilated patients. The additional diagnostic value compared to tracheal aspirations in ventilator-associated pneumonia (VAP) has been questioned. Nevertheless, BAL can provide extra information for the differential diagnosis of respiratory disease and good antibiotic stewardship. These benefits should outweigh potential hazards caused by the invasiveness of this diagnostic technique. The focus of the present study was on the clinical course and complications of patients following BAL procedures up to 24 h.

Methods

Hundred sixty-four FFB guided BAL procedures for suspected pneumonia were analysed in an observational study. The clinical course of patients was monitored by respiratory and haemodynamic data before BAL, 1 and 24 h after BAL. Complications were defined and registered. Factors associated with complications were analysed by logistic regression.

Results

Clinical course: a decrease in average pO₂/FiO₂ ratio 1 h after BAL from 29 kPa (218 mmHg) to 25 kPa (189 mmHg) (p < 0.05) was observed which fully recovered within 24 h. Respiratory complications: the incidence of procedure related hypo-oxygenation (SaO₂ ≤ 88 %) and/or bronchospasm was 9 %; a decrease of >25 % PaO₂/FiO₂ ratio 1 h after BAL was found in 29 % of patients; no bleeding or pneumothorax were registered. Haemodynamic complications: there were no cases of hypertension and cardiac rhythm disturbances; haemodynamic instability within the first 24 h after BAL was recorded in 22 %; this was correlated with a cardiovascular diagnosis at admission (OR 2.9; 95 % CI 1.2 - 6.7) and the presence of cardiovascular co-morbidity (OR 3.5; 95 % CI 1.5 – 8.3). The incidence of bacteraemia was 7 %. There was no case of procedure related death.

Discussion

Frequently occurring haemodynamic and respiratory instability but no cases of cardiac rhythm disturbances, bleeding, pneumothorax or procedure related death were attributable to diagnostic FFB and BAL. The procedures should be conducted under careful supervision by experienced physicians. Only a randomized controlled trial that compares diagnostic FFB and BAL with a non-invasive strategy could ultimately establish the safety profile and clinical utility of these procedures in critically ill ventilated patients.