Diagnosis of ventilator-associated pneumonia using electronic nose sensor array signals: solutions to improve the application of machine learning in respiratory research.

BACKGROUND: Ventilator-associated pneumonia (VAP) is a significant cause of mortality in the intensive care unit. Early diagnosis of VAP is important to provide appropriate treatment and reduce mortality. Developing a noninvasive and highly accurate diagnostic method is important. The invention of electronic sensors has been applied to analyze the volatile organic compounds in breath to detect VAP using a machine learning technique. However, the process of building an algorithm is usually unclear and prevents physicians from applying the artificial intelligence technique in clinical practice. Clear processes of model building and assessing accuracy are warranted. The objective of this study was to develop a breath test for VAP with a standardized protocol for a machine learning technique. METHODS: We conducted a case-control study. This study enrolled subjects in an intensive care unit of a hospital in southern Taiwan from February 2017 to June 2019. We recruited patients with VAP as the case group and ventilated patients without pneumonia as the control group. We collected exhaled breath and analyzed the electric resistance changes of 32 sensor arrays of an electronic nose. We split the data into a set for training algorithms and a set for testing. We applied eight machine learning algorithms to build prediction models, improving model performance and providing an estimated diagnostic accuracy. RESULTS: A total of 33 cases and 26 controls were used in the final analysis. Using eight machine learning algorithms, the mean accuracy in the testing set was 0.81 ± 0.04, the sensitivity was 0.79 ± 0.08, the specificity was 0.83 ± 0.00, the positive predictive value was 0.85 ± 0.02, the negative predictive value was 0.77 ± 0.06, and the area under the receiver operator characteristic curves was 0.85 ± 0.04. The mean kappa value in the testing set was 0.62 ± 0.08, which suggested good agreement. CONCLUSIONS: There was good accuracy in detecting VAP by sensor array and machine learning techniques. Artificial intelligence has the potential to assist the physician in making a clinical diagnosis. Clear protocols for data processing and the modeling procedure needed to increase generalizability.

Performance and impact of a multiplex PCR in ICU patients with ventilator-associated pneumonia or ventilated hospital-acquired pneumonia.

BACKGROUND: Early appropriate antibiotic therapy reduces morbidity and mortality of severe pneumonia. However, the emergence of bacterial resistance requires the earliest use of antibiotics with the narrowest possible spectrum. The Unyvero Hospitalized Pneumonia (HPN, Curetis) test is a multiplex PCR (M-PCR) system detecting 21 bacteria and 19 resistance genes on respiratory samples within 5 h. We assessed the performance and the potential impact of the M-PCR on the antibiotic therapy of ICU patients. METHODS: In this prospective study, we performed a M-PCR on bronchoalveolar lavage (BAL) or plugged telescoping catheter (PTC) samples of patients with ventilated HAP or VAP with Gram-negative bacilli or clustered Gram-positive cocci. This study was conducted in 3 ICUs in a French academic hospital: the medical and infectious diseases ICU, the surgical ICU, and the cardio-surgical ICU. A multidisciplinary expert panel simulated the antibiotic changes they would have made if the M-PCR results had been available. RESULTS: We analyzed 95 clinical samples of ventilated HAP or VAP (72 BAL and 23 PTC) from 85 patients (62 males, median age 64 years). The median turnaround time of the M-PCR was 4.6 h (IQR 4.4-5). A total of 90/112 bacteria were detected by the M-PCR system with a global sensitivity of 80% (95% CI, 73-88%) and specificity of 99% (95% CI 99-100). The sensitivity was better for Gram-negative bacteria (90%) than for Gram-positive cocci (62%) (p = 0.005). Moreover, 5/8 extended-spectrum beta-lactamases (CTX-M gene) and 4/4 carbapenemases genes (3 NDM, one oxa-48) were detected. The M-PCR could have led to the earlier initiation of an effective antibiotic in 20/95 patients (21%) and to early de-escalation in 37 patients (39%) but could also have led to one (1%) inadequate antimicrobial therapy. Among 17 empiric antibiotic treatments with carbapenems, 10 could have been de-escalated in the following hours according to the M-PCR results. The M-PCR also led to 2 unexpected diagnosis of severe legionellosis confirmed by culture methods. CONCLUSIONS: Our results suggest that the use of a M-PCR system for respiratory samples of patients with VAP and ventilated HAP could improve empirical antimicrobial therapy and reduce the use of broad-spectrum antibiotics.

Update of the treatment of nosocomial pneumonia in the ICU.

In accordance with the recommendations of, amongst others, the Surviving Sepsis Campaign and the recently published European treatment guidelines for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), in the event of a patient with such infections, empirical antibiotic treatment must be appropriate and administered as early as possible. The aim of this manuscript is to update treatment protocols by reviewing recently published studies on the treatment of nosocomial pneumonia in the critically ill patients that require invasive respiratory support and patients with HAP from hospital wards that require invasive mechanical ventilation. An interdisciplinary group of experts, comprising specialists in anaesthesia and resuscitation and in intensive care medicine, updated the epidemiology and antimicrobial resistance and established clinical management priorities based on patients' risk factors. Implementation of rapid diagnostic microbiological techniques available and the new antibiotics recently added to the therapeutic arsenal has been reviewed and updated. After analysis of the categories outlined, some recommendations were suggested, and an algorithm to update empirical and targeted treatment in critically ill patients has also been designed. These aspects are key to improve VAP outcomes because of the severity of patients and possible acquisition of multidrug-resistant organisms (MDROs).

Calorie Intake During Status Epilepticus and Outcome: A 5-Year Cohort Study.

OBJECTIVES: Recommendations regarding nutrition during status epilepticus are lacking, and it is unclear whether restriction of calorie intake would result in beneficial effects or potential harm. We thus aimed to investigate associations between daily calorie intake and outcome in adult status epilepticus patients deriving from a 5-year cohort with a systematic and prospective collection of nutritional data. DESIGN: Retrospective observational study. SETTING: Medical ICUs at a tertiary academic medical care center. PATIENTS: Consecutive patients with status epilepticus treated at the ICUs from 2012 to 2016 were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All patients with status epilepticus were monitored regarding nutrition support provided according to the guidelines. Relative risks of no return to baseline were estimated by Poisson regression with robust error variance and adjusted for potential confounders. Of 203 patients, 86 (42%) had return to baseline. Metabolic characteristics of patients with and without return to baseline did not differ. Patients without return to baseline received more calories and proteins per status epilepticus day, and increasing nutritional support was associated with ventilator-associated pneumonia (relative risk, 1.19; 95% CI, 1.09-1.28). Multivariable regression analysis revealed significant increases in relative risks for no return to baseline with every percent of days with nutrition (relative risk, 1.35; 95% CI, 1.05-1.74), with every 100 kcal (relative risk, 1.01; 95% CI, 1.002-1.01), and gram of protein intake (relative risk, 1.01; 95% CI, 1.001-1.01) per status epilepticus day, independent of potential confounders (including fatal etiology, duration and severity of status epilepticus, Charlson comorbidity index, and treatment with anesthetics). CONCLUSIONS: Our results indicate that increased calorie intake during status epilepticus is independently associated with unfavorable outcome. These findings require further validation and investigations into potential mediators, such as induction of ketogenesis, immunomodulating effects, and/or reduction of ICU-associated complications, such as infections.

Mechanical ventilation in patients with acute ischaemic stroke: from pathophysiology to clinical practice.

Most patients with ischaemic stroke are managed on the ward or in specialty stroke units, but a significant number requires higher-acuity care and, consequently, admission to the intensive care unit. Mechanical ventilation is frequently performed in these patients due to swallowing dysfunction and airway or respiratory system compromise. Experimental studies have focused on stroke-induced immunosuppression and brain-lung crosstalk, leading to increased pulmonary damage and inflammation, as well as reduced alveolar macrophage phagocytic capability, which may increase the risk of infection. Pulmonary complications, such as respiratory failure, pneumonia, pleural effusions, acute respiratory distress syndrome, lung oedema, and pulmonary embolism from venous thromboembolism, are common and found to be among the major causes of death in this group of patients. Furthermore, over the past two decades, tracheostomy use has increased among stroke patients, who can have unique indications for this procedure-depending on the location and type of stroke-when compared to the general population. However, the optimal mechanical ventilator strategy remains unclear in this population. Although a high tidal volume (VT) strategy has been used for many years, the latest evidence suggests that a protective ventilatory strategy (VT = 6-8 mL/kg predicted body weight, positive end-expiratory pressure and rescue recruitment manoeuvres) may also have a role in brain-damaged patients, including those with stroke. The aim of this narrative review is to explore the pathophysiology of brain-lung interactions after acute ischaemic stroke and the management of mechanical ventilation in these patients.

Host-pathogen interaction during mechanical ventilation: systemic or compartmentalized response?

Patients admitted to the intensive care unit (ICU) often require invasive mechanical ventilation. Ventilator-associated lower respiratory tract infections (VA-LRTI), either ventilator-associated tracheobronchitis (VAT) or ventilator-associated pneumonia (VAP), are the most common complication among this patient cohort. VAT and VAP are currently diagnosed and treated as separate entities, viewed as binary disease elements despite an inherent subjectivity in distinguishing them clinically. This paper describes a new approach to pulmonary infections in critically ill patients. Our conjecture is that the host-pathogen interaction during mechanical ventilation determines a local compartmentalized or systemic de-compartmentalized response, based on host immunity and inflammation, and the pathogenic potential of the infecting organism. This compartmentalized or de-compartmentalized response establishes disease severity along a continuum of colonization, VAT or VAP. This change in approach is underpinned by the dissemination hypothesis, which acknowledges the role of immune and inflammatory systems in determining host response to pathogenic organisms in the lower respiratory tract. Those with intact immune and inflammatory pathways may limit infection to a compartmentalized VAT, while immunosuppressed mechanically ventilated patients are at greater risk of a de-compartmentalized VAP. Taking this model from the realm of theory to the bedside will require a greater understanding of inflammatory and immune pathways, and the development of novel disease-specific biomarkers and diagnostic techniques. Advances will lead to early initiation of optimal bespoke antimicrobial therapy, where the intensity and duration of therapy are tailored to clinical, immune and biomarker response. This approach will benefit towards a personalized treatment.

Diagnostic Efficacy of Serum Amyloid A Protein and Soluble Intercellular Adhesion Molecule 1 in Pediatric Ventilator-Associated Pneumonia.

OBJECTIVES: Study of inflammatory biomarkers which may aid in early detection of ventilator-associated pneumonia (VAP) in children and predicting their outcome. PATIENTS: Thirty-five children, aged 2 months to 13 years, needed mechanical ventilation (MV) for more than 48 hours due to causes other than pneumonia. METHODS: Measurement of serum amyloid A (SAA) protein, soluble intercellular adhesion molecule 1 (sICAM-1), and C-reactive protein (CRP), modified clinical pulmonary infection score (CPIS) and performing culture of endotracheal aspirate at the start and on the third day of MV. RESULTS: Ventilator-associated pneumonia was diagnosed by CPIS in 6 (17.1%) of 35 patients. On the third day of MV, there was a significant increase in serum mean levels of SAA, sICAM-1, and CRP in comparison to the start of MV ( P = .005, .004, and .01, respectively). Three (50%) of 6 patients with VAP died, while 4 (14.28%) of 28 patients without VAP died. The sensitivity of serum SAA, sICAM-1, and CPIS were 100% for predicting VAP, while specificity was highest for CPIS (96.55%) followed by SAA (93.1%). Combination of CPIS and SAA increased the specificity to 100%. For predicting nonsurvival, serum SAA and sICAM-1 had a sensitivity of 100% and a specificity of 92.86% and 89.29%, respectively. CONCLUSION: Serum amyloid A and sICAM-1 may be considered as reliable markers for detection of VAP. Combination of serum SAA with CPIS increased the specificity to 100%. Measurement of SAA in patients with VAP also had a good predictive value for nonsurvival in such patients.

Early-Onset Ventilator-Associated Pneumonia in Severe Traumatic Brain Injury: is There a Relationship with Prehospital Airway Management?

BACKGROUND: Prehospital airway management in severe traumatic brain injury (TBI) is widely recommended by international guidelines for the management of trauma. Early-onset ventilator-associated pneumonia (EOVAP) is a common occurrence in this population and can worsen mortality and functional outcome. OBJECTIVES: In this retrospective observational study, we aimed to evaluate the association between different prehospital airway management variables and the occurrence of EOVAP. Secondarily we evaluated the correlation between EOVAP and mortality and neurological outcome. METHODS: The study retrospectively evaluated 223 patients admitted from 2010 to 2017 in our trauma intensive care unit for severe TBI. The population was divided into three groups on the basis of the airway management technique adopted (bag mask ventilation, laryngeal tube, orotracheal intubation). Uni- and multivariate logistic regression analyses were performed using the occurrence of EOVAP as the dependent variable, to investigate potential associations with prehospital airway management. RESULTS: A total of 131 episodes (58.7%) of EOVAP were registered in the study population (223 patients). Laryngeal tube and orotracheal intubation were used in patients with significantly lower Glasgow Coma Scale score on scene and a higher Face Abbreviated Injury Scale; advanced airway management significantly increased the total rescue time. The prehospital airway management technique adopted, prehospital type of sedation or use of muscle relaxants, type of transport, and rescue times were not associated with the occurrence of EOVAP. CONCLUSIONS: Prehospital airway management does not have a significant impact on the occurrence of EOVAP in severe TBI patients. Similarly, it does not have a significant impact on mortality or long-term neurological outcome despite increasing duration of mechanical ventilation, intensive care unit, and hospital stay.

Machine Learning Methods Applied to Predict Ventilator-Associated Pneumonia with Pseudomonas aeruginosa Infection via Sensor Array of Electronic Nose in Intensive Care Unit.

One concern to the patients is the off-line detection of pneumonia infection status after using the ventilator in the intensive care unit. Hence, machine learning methods for ventilator-associated pneumonia (VAP) rapid diagnose are proposed. A popular device, Cyranose 320 e-nose, is usually used in research on lung disease, which is a highly integrated system and sensor comprising 32 array using polymer and carbon black materials. In this study, a total of 24 subjects were involved, including 12 subjects who are infected with pneumonia, and the rest are non-infected. Three layers of back propagation artificial neural network and support vector machine (SVM) methods were applied to patients' data to predict whether they are infected with VAP with Pseudomonas aeruginosa infection. Furthermore, in order to improve the accuracy and the generalization of the prediction models, the ensemble neural networks (ENN) method was applied. In this study, ENN and SVM prediction models were trained and tested. In order to evaluate the models' performance, a fivefold cross-validation method was applied. The results showed that both ENN and SVM models have high recognition rates of VAP with Pseudomonas aeruginosa infection, with 0.9479 ± 0.0135 and 0.8686 ± 0.0422 accuracies, 0.9714 ± 0.0131, 0.9250 ± 0.0423 sensitivities, and 0.9288 ± 0.0306, 0.8639 ± 0.0276 positive predictive values, respectively. The ENN model showed better performance compared to SVM in the recognition of VAP with Pseudomonas aeruginosa infection. The areas under the receiver operating characteristic curve of the two models were 0.9842 ± 0.0058 and 0.9410 ± 0.0301, respectively, showing that both models are very stable and accurate classifiers. This study aims to assist the physician in providing a scientific and effective reference for performing early detection in Pseudomonas aeruginosa infection or other diseases.

Pathophysiology of Escherichia coli pneumonia: Respective contribution of pathogenicity islands to virulence.

Ventilator-associated pneumonia (VAP) remains the most frequent life-threatening nosocomial infection. Enterobacteriaceae including Escherichia coli are increasingly involved. If a cumulative effect of pathogenicity islands (PAIs) has been shown for E. coli virulence in urinary tract or systemic infections, very little is known regarding pathophysiology of E. coli pneumonia. This study aimed to determine the role of each of the 7 PAIs present in pathogenic E. coli strain 536 in pneumonia pathophysiology. We used mutant strains to screen pathophysiological role of PAI in a rat pneumonia model. We also test individual gene mutants within PAI identified to be involved in pneumonia pathogenesis. Finally, we determined the prevalence of these genes of interest in E. coli isolates from feces and airways of ventilated patients. Only PAIs I and III were significantly associated with rat pneumonia pathogenicity. Only the antigen-43 (Ag43) gene in PAI III was significantly associated with bacterial pathogenicity. The prevalence of tested genes in fecal and airway isolates of ventilated patients did not differ between isolates. In contrast, genes encoding Ag43, the F17-fimbriae subunits, HmuR and SepA were more prevalent in VAP isolates with statistical significance for hmuR when compared to airway colonizing isolates. The E. coli PAIs involved in lung pathogenicity differed from those involved in urinary tract and bloodstream infections. Overall, extraintestinal E. coli virulence seems to rely on a combination of numerous virulence genes that have a cumulative effect depending on the infection site.

Neutrophil extracellular traps (NETs) are increased in the alveolar spaces of patients with ventilator-associated pneumonia.

BACKGROUND: Neutrophils release neutrophil extracellular traps (NETs) in response to invading pathogens. Although NETs play an important role in host defense against microbial pathogens, they have also been shown to play a contributing mechanistic role in pathologic inflammation in the absence of infection. Although a role for NETs in bacterial pneumonia and acute respiratory distress syndrome (ARDS) is emerging, a comprehensive evaluation of NETs in the alveolar space of critically ill patients has yet to be reported. In this study, we evaluated whether markers of NET formation in mechanically ventilated patients are associated with ventilator-associated pneumonia (VAP). METHODS: We collected bronchoalveolar lavage fluid from 100 critically ill patients undergoing bronchoscopy for clinically suspected VAP. Subjects were categorized by the absence or presence of VAP and further stratified by ARDS status. NETs (myeloperoxidase (MPO)-DNA complexes) and the NET-associated markers peroxidase activity and cell-free DNA were analyzed by enzyme-linked immunosorbent assay and colorimetric assays, respectively. Quantitative polymerase chain reaction of nuclear and mitochondrial DNA was used to determine the origin of the extruded DNA. Interleukin (IL)-8 and calprotectin were assayed as measures of alveolar inflammation and neutrophil activation. Correlations between NETs and markers of neutrophil activation were determined using Spearman's correlation. We tested for associations with VAP and bacterial burden by logistic and linear regression, respectively, using log10-transformed NETs. RESULTS: MPO-DNA concentrations were highly correlated with other measures of NET formation in the alveolar space, including cell-free DNA and peroxidase activity (r = 0.95 and r = 0.87, p < 0.0001, respectively). Alveolar concentrations of MPO-DNA were higher in subjects with VAP and ARDS compared with those with ARDS alone (p < 0.0001), and higher MPO-DNA was associated with increased odds of VAP (odds ratio 3.03, p < 0.0001). In addition, NET concentrations were associated with bacterial burden (p < 0.0001) and local alveolar inflammation as measured by IL-8 (r = 0.89, p < 0.0001). CONCLUSIONS: Alveolar NETs measured by MPO-DNA complex are associated with VAP, and markers of NETosis are associated with local inflammation and bacterial burden in the lung. These results suggest that NETs contribute to inflammatory responses involved in the pathogenesis of VAP.

Prognostic Risk Factors in Ventilator-Associated Pneumonia.

BACKGROUND Ventilator-associated pneumonia (VAP) is a nosocomial infection commonly seen in patients in intensive care units (ICU). This study aimed to analyze factors affecting prognosis of patients diagnosed with VAP. MATERIAL AND METHODS Critically ill patients with VAP were retrospectively evaluated between June 2002 and June 2011 in the ICU. VAP diagnosis was made according to 2005 ATS/IDSA (Infectious Diseases Society of America/American Thoracic Society) criteria. First pneumonia attacks of patients were analyzed. RESULTS When early- and late-onset pneumonia causes were compared according to ICU and hospital admittance, resistant bacteria were found to be more common in pneumonias classified as early-onset according to ICU admittance. APACHE II score of >21 (p=0.016), SOFA score of >6 (p<0.001) on admission to ICU and SOFA score of >6 (p<0.001) on day of diagnosis are risk factors affecting mortality. Additionally, low PaO2/FIO2 ratio at onset of VAP had a negative effect on prognosis (p<0.001). SOFA score of >6 on the day of VAP diagnosis was an independent risk factor for mortality [(p<0.001; OR (95%CI): 1.4 (1.2-1.6)]. CONCLUSIONS Resistant bacteria might be present in early-onset VAP. Especially, taking LOS into consideration may better estimate the presence of resistant bacteria. Acinetobacter baumannii, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus (MRSA) were the most frequent causative microorganisms for VAP. SOFA score might be more valuable than APACHE II score. Frequently surveilling SOFA scores may improve predictive performance over time.

Subglottic secretion suction for preventing ventilator-associated pneumonia: an updated meta-analysis and trial sequential analysis.

BACKGROUND: Potential benefits of subglottic secretion suction for preventing ventilator-associated pneumonia (VAP) are not fully understood. METHODS: We searched Cochrane Central, PubMed, and EMBASE up to March 2016 to identify randomized controlled trials (RCTs) that compared subglottic secretion suction versus non-subglottic secretion suction in adults with mechanical ventilation. Meta-analysis was conducted using Revman 5.3, trial sequential analysis (TSA) 0.9 and STATA 12.0. The primary outcome was incidence of VAP. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to evaluate the level of evidence. RESULTS: Twenty RCTs (N = 3544) were identified. Subglottic secretion suction was associated with reduction of VAP incidence in four high quality trials (relative risk (RR) 0.54, 95 % confidence interval (CI) 0.40-0.74; p < 0.00001) and in all trials (RR = 0.55, 95 % CI 0.48- 0.63; p < 0.00001). Sensitivity analyses did not show differences in the pooled results. Additionally, the results of the above-mentioned analyses were confirmed in TSA. GRADE level was high. Subglottic secretion suction significantly reduced incidence of early onset VAP, gram-positive or gram-negative bacteria causing VAP, and duration of mechanical ventilation. It delayed the time-to-onset of VAP. However, no significant differences in late onset VAP, intensive care unit (ICU) mortality, hospital mortality, or ICU length of stay were found. CONCLUSIONS: Subglottic secretion suction decreased VAP incidence and duration of mechanical ventilation and delayed VAP onset. However, subglottic secretion suction did not reduce mortality and length of ICU stay. Subglottic secretion suction is recommended for preventing VAP and for reducing ventilation length, especially in the population at high risk of early onset VAP. TRIAL REGISTRATION: A protocol of this meta-analysis has been registered on PROSPERO (registration number: CRD42015015715 ); registered on 5 January 2015.

Does hyperoxia enhance susceptibility to secondary pulmonary infection in the ICU?

Hyperoxia is common practice in the acute management of circulatory shock, and observational studies report that it is present in more than 50 % of mechanically ventilated patients during the first 24 h after intensive care unit (ICU) admission. On the other hand, "oxygen toxicity" due to the increased formation of reactive oxygen species limits its use due to serious deleterious side effects. However, formation of reactive oxygen species to boost bacterial killing is one of the body's anti-microbial auto-defense mechanisms and, hence, O2 has been referred to as an antibiotic. Consequently, hyperoxia during the peri-operative period has been advocated for surgical patients in order to reduce surgical site infection. However, there is ample evidence that long-term exposure to hyperoxia impaired bacterial phagocytosis and thereby aggravated both bacterial burden and dissemination. Moreover, a recent retrospective study identified the number of days with hyperoxia, defined as a PaO2 > 120 mmHg only, as an independent risk factor of ventilator-associated pneumonia in patients needing mechanical ventilation for more than 48 h. Since so far the optimal oxygenation target is unknown for ICU patients, "conservative" O2 therapy represents the treatment of choice to avoid exposure to both hypoxemia and excess hyperoxemia.

[DIAGNOSTIC AND THERAPEUTIC BRONCHOSCOPY IN PATIENTS UNDERGOING CARDIAC SURGERY IN INTRA- AND POSTOPERATIVE PERIODS].

The article presents research conducted to evaluate the use of diagnostic and therapeutic fiberoptic bronchoscopy in the treatment of ventilator-associated pneumonia (VAP) and tracheobronchitis in patients in cardiac ICU. The paper presents the results of the study and comparison of invasive techniques for sampling from the respiratory tract for bacteriological analysis. We studied the bacterial profile of ICU, original content of the respiratory tract of cardiac patients in the intraoperative period and possible ways for prevention of VAP and tracheobronchitis in the postoperative period using bronchoscopy. In addition data on the effect of bronchoscopy on the respiratory and cardiovascular systems in cardiac surgical patients undergoing mechanical ventilation presented.

Risk factors for ventilator-associated pneumonia: among trauma patients with and without brain injury.

Ventilator-associated pneumonia (VAP) rates remain highest among trauma and brain injured patients; yet, no research compares VAP risk factors between the 2 groups. This retrospective, case-controlled study identified risk factors for VAP among critically ill trauma patients with and without brain injury. Data were abstracted on trauma patients with (cases) and without (controls) brain injury. Data gathered on n = 157 subjects. Trauma patients with brain injury had more emergent and field intubations. Age was strongest predictor of VAP in cases, and ventilator days predicted VAP in controls. Trauma patients with brain injury may be at higher risk for VAP.

Factors predicting ventilator dependence in patients with ventilator-associated pneumonia.

OBJECTIVES: To determine risk factors associated with ventilator dependence in patients with ventilator-associated pneumonia (VAP). STUDY DESIGN: A retrospective study was conducted at Chang Gung Memorial Hospital, Kaohsiung, from January 1, 2007 to January 31, 2008. METHODS: This study evaluated 163 adult patients (aged ≥ 18 years). Eligibility was evaluated according to the criterion for VAP, Sequential Organ Failure Assessment (SOFA) score, Acute Physiological Assessment and Chronic Health Evaluation II (APACHE II) score. Oxygenation index, underlying comorbidities, septic shock status, previous tracheostomy status, and factors related to pneumonia were collected for analysis. RESULTS: Of the 163 VAP patients in the study, 90 patients survived, yielding a mortality rate of 44.8%. Among the 90 surviving patients, only 36 (40%) had been weaned off ventilators at the time of discharge. Multivariate logistic regression analysis was used to identify underlying factors such as congestive cardiac failure (P = 0.009), initial high oxygenation index value (P = 0.04), increased SOFA scores (P = 0.01), and increased APACHE II scores (P = 0.02) as independent predictors of ventilator dependence. Results from the Kaplan-Meier method indicate that initial therapy with antibiotics could increase the ventilator weaning rate (log Rank test, P < 0.001). CONCLUSIONS: Preexisting cardiopulmonary function, high APACHE II and SOFA scores, and high oxygenation index were the strongest predictors of ventilator dependence. Initial empiric antibiotic treatment can improve ventilator weaning rates at the time of discharge.

Subglottic secretion drainage for the prevention of ventilator-associated pneumonia: a systematic review and meta-analysis.

BACKGROUND AND PURPOSE: Aspiration of secretions containing bacterial pathogens into the lower respiratory tract is the main cause of ventilator-associated pneumonia. Endotracheal tubes with subglottic secretion drainage can potentially reduce this and, therefore, the incidence of ventilator-associated pneumonia. New evidence on subglottic secretion drainage as a preventive measure for ventilator-associated pneumonia has been recently published and to consider the evidence in totality, we conducted an updated systematic review and meta-analysis. DESIGN: We searched computerized databases, reference lists, and personal files. We included randomized clinical trials of mechanically ventilated patients comparing standard endotracheal tubes to those with subglottic secretion drainage and reporting on the occurrence of ventilator-associated pneumonia. Studies were meta-analyzed for the primary outcome of ventilator-associated pneumonia and secondary clinical outcomes. MEASUREMENTS AND MAIN RESULTS: We identified 13 randomized clinical trials that met the inclusion criteria with a total of 2442 randomized patients. Of the 13 studies, 12 reported a reduction in ventilator-associated pneumonia rates in the subglottic secretion drainage arm; in meta-analysis, the overall risk ratio for ventilator-associated pneumonia was 0.55 (95% confidence interval, 0.46-0.66; p < .00001) with no heterogeneity (I = 0%). The use of subglottic secretion drainage was associated with reduced intensive care unit length of stay (-1.52 days; 95% confidence interval, -2.94 to -0.11; p = .03); decreased duration of mechanically ventilated (-1.08 days; 95% confidence interval, -2.04 to -0.12; p = .03), and increased time to first episode of ventilator-associated pneumonia (2.66 days; 95% confidence interval, 1.06-4.26; p = .001). There was no effect on adverse events or on hospital or intensive care unit mortality. CONCLUSIONS: In those at risk for ventilator-associated pneumonia, the use of endotracheal tubes with subglottic secretion drainage is effective for the prevention of ventilator-associated pneumonia and may be associated with reduced duration of mechanical ventilation and intensive care unit length of stay.

Respiratory care year in review 2010: part 1. asthma, COPD, pulmonary function testing, ventilator-associated pneumonia.

The purpose of this paper is to review the recent literature related to asthma, COPD, pulmonary function testing, and ventilator-associated pneumonia. Topics covered related to asthma include genetics and epigenetics; exposures; viruses; diet, obesity and exercise; exhaled nitric oxide; and drug therapy (ß agonists, macrolides, tiotropium and monteleukast). Topics covered related to COPD include childhood disadvantage factors and COPD; vitamin D deficiency and COPD; ß-blockers and COPD; corticosteroid therapy during COPD exacerbations; oxygen administration during pre-hospital transport of patients with COPD exacerbation; and prognosis of patients admitted to the hospital for COPD exacerbation. Topics related to pulmonary function testing include methods and techniques; predicted values; natural history, pulmonary function in health and disease; and the COPD controversy. Finally, the paper includes the following topics related to ventilator-associated pneumonia: the tube, the intubation route, and the cuff; mechanical ventilation; the bundle; and cost. These topics were chosen and reviewed in a manner that is most likely to have interest to the readers of Respiratory Care.

[Nosocomial pneumonia. Prevention and diagnostic]. / Nosokomiale Pneumonie. Prävention und Diagnostik.

Pneumonia occurring more than 48 h after induction of mechanical ventilation is called ventilator-associated pneumonia (VAP). VAP is the most common nosocomial infection in intensive care medicine and is associated with prolonged intensive care and hospital stay and a higher mortality. The main pathomechanism for development of ventilator-associated pneumonia is not so much the mechanical ventilation per se but more the pathogens passing along the tube towards the lungs. Avoidance of tracheal intubation, strict hygienic measures, reduction of oropharyngeal colonization and the avoidance of microaspiration are the most promising prevention strategies. Therapeutic success in treatment of VAP is coupled to an early diagnosis and therapy. Suspicion of pneumonia is based on clinical and radiologic criteria. Biomarkers and microbiological findings are important for follow-up and reevaluation of the suspected diagnosis.