Effect of ventilator-associated pneumonia on mortality and morbidity

Hospital-acquired Infections in the Adult Intensive Care Unit: Epidemiology, Resistance Patterns, and Risk Factors

INTRODUCTION

Hospital-acquired infections (HAIs) are defined as infections that develop in the patient after being admitted to the hospital. The overall burden of HAIs is known to be higher in developing countries. The most common HAIs include ventilator-associated pneumonia (VAP), catheter-associated urinary tract infection (CAUTI), surgical site infection (SSI), and catheter-related bloodstream infections (CRBSI).

OBJECTIVES

Due to limited recent literature, we aimed to evaluate the incidence rates and causative organisms of intensive care unit (ICU)-acquired infections at our tertiary care center and to determine the factors associated with mortality in patients with ICU-acquired infections.

METHODS

Single-center prospective, observational study.

RESULTS

The incidence rates in our study were: VAP incidence rate: 105/2681 = 39.1/1000 ventilator days, CRBSI incidence rate: 38/4871 = 7.8/1000 central venous catheter (CVC) days, CAUTI incidence rate: 54/11201 = 4.8/1000 urinary catheter days. Acinetobacter baumannii accounted for 41% of the infections in patients with VAP and 21% in patients with CRBSI. E. coli was the most common causative organism in the CAUTI group, accounting for 33% of the infections. Age >50 years, presence of hypotension on presentation, medical diagnosis, multiple ICU-acquired infections, and higher APACHE-II score on admission are the statistically significant determinants of the incidence of mortality in the overall group (p-value >0.05 for all).

CONCLUSION

Age >50 years, presence of hypotension on presentation, medical diagnosis, multiple ICU-acquired infections, and higher APACHE-II score on admission must be kept in mind as determinants of the incidence of mortality in HAIs.

Rebound Inverts the Staphylococcus aureus Bacteremia Prevention Effect of Antibiotic Based Decontamination Interventions in ICU Cohorts with Prolonged Length of Stay

Could rebound explain the paradoxical lack of prevention effect against Staphylococcus aureus blood stream infections (BSIs) with antibiotic-based decontamination intervention (BDI) methods among studies of ICU patients within the literature? Two meta-regression models were applied, each versus the group mean length of stay (LOS). Firstly, the prevention effects against S. aureus BSI [and S. aureus VAP] among 136 studies of antibiotic-BDI versus other interventions were analyzed. Secondly, the S. aureus BSI [and S. aureus VAP] incidence in 268 control and intervention cohorts from studies of antibiotic-BDI versus that among 165 observational cohorts as a benchmark was modelled. In model one, the meta-regression line versus group mean LOS crossed the null, with the antibiotic-BDI prevention effect against S. aureus BSI at mean LOS day 7 (OR 0.45; 0.30 to 0.68) inverted at mean LOS day 20 (OR 1.7; 1.1 to 2.6). In model two, the meta-regression line versus group mean LOS crossed the benchmark line, and the predicted S. aureus BSI incidence for antibiotic-BDI groups was 0.47; 0.09-0.84 percentage points below versus 3.0; 0.12-5.9 above the benchmark in studies with 7 versus 20 days mean LOS, respectively. Rebound within the intervention groups attenuated and inverted the prevention effect of antibiotic-BDI against S. aureus VAP and BSI, respectively. This explains the paradoxical findings.

Short-course versus prolonged-course antibiotic regimens for ventilator-associated pneumonia: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Current guidelines recommend short-duration antibiotic therapy for non-fermenting gram-negative bacilli (NF-GNB) ventilator-associated pneumonia (VAP) which may be associated with a higher recurrence of pneumonia. In this meta-analysis, we aimed to compare short- versus prolonged-course antibiotic regimens for VAP.

METHODS

We searched several databases for randomized controlled trials (RCTs) that compared the effectiveness of a short- versus long-course of antibiotic treatment in patients with VAP. Data analysis was performed using RevMan 5.4.

RESULTS

Our pooled analysis consisted of six RCTs. For 28-day mortality, no significant difference was found between the prolonged course and the short course. Administration of a short course of antibiotics increased the risk of recurrence of pneumonia in patients with VAP due to NF-GNB (RR 1.73; 95% CI: 1.17-2.54). Secondary outcomes, such as clinical resolution, duration of ICU stay, and duration of mechanical ventilation, revealed no significant difference between the two regimens. The quality of evidence was low for most outcomes.

CONCLUSIONS

Low-quality evidence suggests that a short course of antibiotics is associated with a higher recurrence of pneumonia in NF-GNB VAP with no difference in mortality as compared to a prolonged course. For definitive conclusions, large-scale and blinded RCTs are required.

Pediatric Cervicofacial Necrotizing Fasciitis-A Challenge for a Medical Team

Cervical necrotizing fasciitis is a very rare complication of a bacterial infection that can have a dental cause. This type of infection typically affects fascial plane, which has a poor blood supply and can affect soft tissue and cervical fascia and can spread quickly causing infection of mediastinum. Initially, in the first stage, the overlying tissues are unaffected, and this can delay diagnosis and surgical intervention. Incidence in children is extremely rare and can be frequently associated with various other general pathologies that decrease the immune system response. We present a case of a young 12-year-old boy diagnosed with this type of infection in the head and neck as a complication of a second inferior molar pericoronitis. The treatment and the management of the case was difficult not only due to the presence of the infection but also because of the prolonged intubation.

Machine learning for the prediction of successful extubation among patients with mechanical ventilation in the intensive care unit: A retrospective observational study

BACKGROUND

Ventilator weaning protocols are commonly implemented for patients receiving mechanical ventilation. However, the rate of extubation failure remains high despite the protocols. This study investigated the usefulness and accuracy of ventilator weaning through machine learning to predict successful extubation.

METHODS

We retrospectively evaluated the data of patients who underwent intubation for respiratory failure and received mechanical ventilation in the intensive care unit (ICU). Data on 57 factors including patient demographics, vital signs, laboratory data, and data from ventilator were extracted. Extubation failure was defined as re-intubation within 72 hours of extubation. For supervised learning, the data were labeled requirement of intubation or not. We used three learning algorithms (Random Forest, XGBoost, and LightGBM) to predict successful extubation. We also analyzed important features and evaluated the area under curve (AUC) and prediction metrics.

RESULTS

Overall, 13 of the 117 included patients required re-intubation. LightGBM had the highest AUC (0.950), followed by XGBoost (0.946) and Random Forest (0.930). The accuracy, precision, and recall performance were 0.897, 0.910, and 0.909, for Random Forest; 0.910, 0.912, and 0.931 for XGBoost; and 0.927, 0.915, and 0.960 for LightGBM, respectively. The most important feature was the duration of mechanical ventilation followed by the fraction of inspired oxygen, positive end-expiratory pressure, maximum and mean airway pressures, and Glasgow Coma Scale.

CONCLUSIONS

Machine learning could predict successful extubation among patients on mechanical ventilation in the ICU. LightGBM has the highest overall performance. The duration of mechanical ventilation was the most important feature in all models.

Microbiology of Ventilator-associated Pneumonia in a Tertiary Care Cancer Hospital

Background

Ventilator-associated pneumonia (VAP) is an important cause of healthcare-associated infections, resulting in prolonged hospitalization with increased morbidity and mortality. Knowledge of predominant local pathogens and their antimicrobial susceptibility patterns helps in selection of appropriate initial antibiotic therapy in these critical cases.

Aim and objective

The aim and objective of this study is to characterize the microbiology and antimicrobial susceptibility patterns of VAP isolates in a tertiary cancer center.

Materials and methods

This is a 4-year qualitative observational study carried out at a tertiary care cancer hospital in Mumbai. All nondirect bronchoalveolar lavage specimens from patients with a clinical suspicion of VAP sent from the critical care unit to the department of microbiology were processed as per standard laboratory procedures. All isolates were identified to species level and an antimicrobial susceptibility testing was performed by the Kirby–Bauer disk diffusion method and/or the VITEK 2 automated identification and susceptibility system, according to Clinical and Laboratory Standards Institute guidelines.

Results

The study comprised 1,074 patients: 710 (66.10%) men and 364 (33.90%) women. A total of 827 bacterial isolates were obtained with 780 (94.32%) gram-negative organisms and 47 (5.68%) gram-positive organisms; of which Acinetobacter baumannii (38.7%), Pseudomonas aeruginosa (17.5%), and Klebsiella pneumoniae (16.6%) were the commonest. Of gram-negative bacilli, multidrug-resistant organisms constituted 87.50% and were susceptible to colistin.

Conclusions

VAP is associated with pathogens, such as A. baumannii, P. aeruginosa, and K. pneumoniae in our setting. High rates of resistance to aminoglycosides, β-lactam-β-lactamase inhibitor combinations, and carbapenems were noted.

How to cite this article

Sangale A, Bhat V, Kelkar R, Biswas S. Microbiology of Ventilator-associated Pneumonia in a Tertiary Care Cancer Hospital. Indian J Crit Care Med 2021;25(4):421–428.

Ventilator-associated pneumonia in adults: a narrative review

Ventilator-associated pneumonia (VAP) is one of the most frequent ICU-acquired infections. Reported incidences vary widely from 5 to 40% depending on the setting and diagnostic criteria. VAP is associated with prolonged duration of mechanical ventilation and ICU stay. The estimated attributable mortality of VAP is around 10%, with higher mortality rates in surgical ICU patients and in patients with mid-range severity scores at admission. Microbiological confirmation of infection is strongly encouraged. Which sampling method to use is still a matter of controversy. Emerging microbiological tools will likely modify our routine approach to diagnosing and treating VAP in the next future. Prevention of VAP is based on minimizing the exposure to mechanical ventilation and encouraging early liberation. Bundles that combine multiple prevention strategies may improve outcomes, but large randomized trials are needed to confirm this. Treatment should be limited to 7 days in the vast majority of the cases. Patients should be reassessed daily to confirm ongoing suspicion of disease, antibiotics should be narrowed as soon as antibiotic susceptibility results are available, and clinicians should consider stopping antibiotics if cultures are negative.

Predictors of oxygenation impairment in medical treatment for type B acute aortic dissection

Lung oxygenation impairment often occurs in patients with type B acute aortic dissection (AAD), necessitating mechanical ventilation. Patients receiving mechanical ventilation are at risk of complications, so a low-oxygen condition requiring mechanical ventilation should be avoided. We explored the predictors of oxygenation impairment. We enrolled 46 patients with type B AAD who had been medically treated and underwent computed tomography. Blood was sampled to measure markers of inflammation, such as the C-reactive protein (CRP) levels and white blood cell count. The arterial partial pressure of oxygen/fraction of inspired oxygen ratio (PaO2/FiO2) was calculated to quantify the severity of respiratory failure. Spearman's rank correlation analysis revealed that the minimum PaO2/FiO2 ratio was significantly correlated with gender, age, and current smoker, and the peak CRP, body temperature, and D-dimer values. A multivariate regression analysis revealed that younger age, male sex, and the peak CRP level were significant predictors of the minimum PaO2/FiO2 ratio (P = 0.01, 0.035 and 0.005, respectively). A covariance structure analysis showed that a younger age and the peak CRP level were significant predictors of oxygenation impairment in type B AAD. Oxygenation impairment in type B AAD is correlated with younger age and a higher peak CRP level. This will enable the identification of patients whose respiratory condition is susceptible to worsening and help prevent mechanical ventilation, leading to the provision of appropriate therapy.

World-Wide Variation in Incidence of Staphylococcus aureus Associated Ventilator-Associated Pneumonia: A Meta-Regression

Staphylococcus aureus (S. aureus) is a common Ventilator-Associated Pneumonia (VAP) isolate. The objective here is to define the extent and possible reasons for geographic variation in the incidences of S. aureus-associated VAP, MRSA-VAP and overall VAP. A meta-regression model of S. aureus-associated VAP incidence per 1000 Mechanical Ventilation Days (MVD) was undertaken using random effects methods among publications obtained from a search of the English language literature. This model incorporated group level factors such as admission to a trauma ICU, year of publication and use of bronchoscopic sampling towards VAP diagnosis. The search identified 133 publications from seven worldwide regions published over three decades. The summary S. aureus-associated VAP incidence was 4.5 (3.9–5.3) per 1000 MVD. The highest S. aureus-associated VAP incidence is amongst reports from the Mediterranean (mean; 95% confidence interval; 6.1; 4.1–8.5) versus that from Asian ICUs (2.1; 1.5–3.0). The incidence of S. aureus-associated VAP varies by up to three-fold (for the lowest versus highest incidence) among seven geographic regions worldwide, whereas the incidence of VAP varies by less than two-fold. Admission to a trauma unit is the most important group level correlate for S. aureus-associated VAP.

Unusually High Incidences of Staphylococcus aureus Infection within Studies of Ventilator Associated Pneumonia Prevention Using Topical Antibiotics: Benchmarking the Evidence Base

Selective digestive decontamination (SDD, topical antibiotic regimens applied to the respiratory tract) appears effective for preventing ventilator associated pneumonia (VAP) in intensive care unit (ICU) patients. However, potential contextual effects of SDD on Staphylococcus aureus infections in the ICU remain unclear. The S. aureus ventilator associated pneumonia (S. aureus VAP), VAP overall and S. aureus bacteremia incidences within component (control and intervention) groups within 27 SDD studies were benchmarked against 115 observational groups. Component groups from 66 studies of various interventions other than SDD provided additional points of reference. In 27 SDD study control groups, the mean S. aureus VAP incidence is 9.6% (95% CI; 6.9–13.2) versus a benchmark derived from 115 observational groups being 4.8% (95% CI; 4.2–5.6). In nine SDD study control groups the mean S. aureus bacteremia incidence is 3.8% (95% CI; 2.1–5.7) versus a benchmark derived from 10 observational groups being 2.1% (95% CI; 1.1–4.1). The incidences of S. aureus VAP and S. aureus bacteremia within the control groups of SDD studies are each higher than literature derived benchmarks. Paradoxically, within the SDD intervention groups, the incidences of both S. aureus VAP and VAP overall are more similar to the benchmarks.

Aspiration and the Risk of Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is a major concern in the intensive care unit. It is estimated that the risk of developing VAP may be as high as 1% per ventilated day, and the attributable mortality approaches 50% in some series. A growing body of evidence implicates the role of microaspiration of contaminated oropharyngeal and perhaps gastroesophageal secretions into the airways as an integral step in the pathogenesis of VAP. In patients who have been intubated and mechanically ventilated for >72 hours, the majority of VAP is caused by enteric gram-negative organisms, presumably of gastrointestinal origin. As a result, strategies designed to minimize the risk of these contaminated secretions into the normally sterile airways are of paramount importance in terms of VAP prevention. This review highlights the important etiological role of the gut in the development of VAP and also discusses the evidence behind interventions that may modulate the risk of both aspiration and subsequent VAP.

World-wide variation in incidence of Acinetobacter associated ventilator associated pneumonia: a meta-regression

Background

Acinetobacter species such as Acinetobacter baumanii are of increasing concern in association with ventilator associated pneumonia (VAP). In the ICU, Acinetobacter infections are known to be subject to seasonal variation but the extent of geographic variation is unclear. The objective here is to define the extent and possible reasons for geographic variation for Acinetobacter associated VAP whether or not these isolates are reported as Acinetobacter baumanii.

Methods

A meta-regression model of VAP associated Acinetobacter incidence within the published literature was undertaken using random effects methods. This model incorporated group level factors such as proportion of trauma admissions, year of publication and reporting practices for Acinetobacter infection.

Results

The search identified 117 studies from seven worldwide regions over 29 years. There is significant variation in Acinetobacter species associated VAP incidence among seven world-wide regions. The highest incidence is amongst reports from the Middle East (mean; 95 % confidence interval; 8.8; 6 · 2–12 · 7 per 1000 mechanical ventilation days) versus that from North American ICU’s (1 · 2; 0 · 8–2 · 1). There is a similar geographic related disparity in incidence among studies reporting specifically as Acinetobacter baumanii. The incidence in ICU’s with a majority of admission being for trauma is >2.5 times that of other ICU’s.

Conclusion

There is greater than fivefold variation in Acinetobacter associated VAP among reports from various geographic regions worldwide. This variation is not explainable by variations in rates of VAP overall, admissions for trauma, publication year or Acinetobacter reporting practices as group level variables.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1921-4) contains supplementary material, which is available to authorized users.

Inapparent Outbreaks of Ventilator-Associated Pneumonia An Ecologic Analysis of Prevention and Cohort Studies

Objective:

To compare ventilator-associated pneumonia (VAP) rates and patterns of isolates across studies of antibiotic and non-antibiotic methods for preventing VAP.

Design:

With the use of 42 cohort study groups as the reference standard, the prevalence of VAP was modeled in two linear regressions: one with the control groups and the other with the intervention groups of 96 VAP prevention studies. The proportion of patients admitted with trauma and the VAP diagnostic criteria were used as ecologic correlates. Also, the patterns of pathogenic isolates were available for 117 groups.

Results:

In the first regression model, the VAP rates for the control groups of antibiotic-based prevention studies were at least 18 (CI95, 12 to 24) per 100 patients higher than those in the cohort study groups (P< .001). By contrast, comparisons of cohort study groups with all other control and intervention groups in the first and second regression models yielded differences that were less than 6 per 100 and not significant (P> .05). For control groups with VAP rates greater than 35%, the patterns of VAP isolates, such as the proportion ofStaphylococcus aureus,more closely resembled those in the corresponding intervention groups than in the cohort groups.

Conclusions:

The rates of VAP in the control groups of the antibiotic prevention studies were significantly higher than expected and the patterns of pathogenic isolates were unusual. These observations suggest that inapparent outbreaks of VAP occurred in these studies. The possibility remains that antibiotic-based VAP prevention presents a major cross-infection hazard.

Soluble Vascular Cell Adhesion Molecule-1 (sVCAM-1) Is Elevated in Bronchoalveolar Lavage Fluid of Patients with Acute Respiratory Distress Syndrome

INTRODUCTION

Pulmonary vascular endothelial activation has been implicated in acute respiratory distress syndrome (ARDS), yet little is known about the presence and role of endothelial activation markers in the alveolar space in ARDS. We hypothesized that endothelial activation biomarkers would be differentially expressed in bronchoalveolar lavage fluid from patients with ARDS compared with healthy volunteers, and that biomarker concentrations would be associated with ARDS severity.

METHODS

We performed a cross-sectional analysis of data from 26 intubated patients with ARDS undergoing evaluation for clinically suspected ventilator-associated pneumonia and five healthy volunteers. Patients underwent bronchoalveolar lavage a median of five days after intubation. Healthy volunteers also underwent bronchoalveolar lavage. Endothelial activation biomarkers (soluble vascular cell adhesion molecule-1 [sVCAM-1], soluble endothelial selectin [sESEL], angiopoietin-1 [Ang-1] and angiopoietin-2 [Ang-2]) were measured in bronchoalveolar lavage fluid. Clinically suspected ventilator-associated pneumonia was confirmed with microbiologic culture data.

RESULTS

Patients with ARDS had significantly higher median sVCAM-1 concentrations in the bronchoalveolar lavage fluid compared with healthy volunteers (985 vs 119 pg/mL, p = 0.03). Additionally, there was a trend toward greater bronchoalveolar lavage fluid sVCAM-1 concentrations among patients with moderate/severe compared to mild ARDS (1395 vs 209 pg/mL, p = 0.06). We did not detect significant differences in bronchoalveolar lavage fluid levels of sESEL, Ang-1 or Ang-2 between patients with ARDS and healthy volunteers. Median bronchoalveolar lavage fluid biomarker levels did not differ between patients with and without microbiologically-confirmed ventilator-associated pneumonia.

CONCLUSIONS

sVCAM-1 concentrations were significantly higher in the bronchoalveolar lavage fluid of patients with ARDS compared to healthy controls, and tended to be higher in moderate/severe ARDS compared to mild ARDS. Our findings add to the growing evidence supporting the concept that endothelial activation plays an important mechanistic role in the pathogenesis of ARDS. Further studies are necessary to characterize the role and/or clinical significance of sVCAM-1 and other endothelial activation markers present in the alveolar space in ARDS.

Evaluation of a systematic approach to weaning of tracheotomized neurological patients: an early interrupted randomized controlled trial

Background

While a systematic approach to weaning reduces the rate of extubation failure in intubated brain-injured patients, no data are available on the weaning outcome of these patients after tracheotomy. We aimed to assess whether a systematic approach to disconnect tracheotomized neurological and neurosurgical patients off the ventilator (intervention) is superior to the sole physician’s judgment (control). Based on previous work in intubated patients, we hypothesized a reduction of the rate of failure within 48 h from 15 to 5 %. Secondary endpoints were duration of mechanical ventilation, ICU length of stay and mortality.

Methods

We designed a single center randomized controlled study. Since no data are available on tracheotomized patients, we based our a priori power analysis on results derived from intubated patients and calculated an overall sample size of 280 patients.

Results

After inclusion of 168 consecutive patients, the trial was interrupted because the attending physicians judged the observed rate of reconnection to be much greater than expected. The overall rate of failure was 29 %, confirming the physicians’ judgment. Twenty-one patients (24 %) in the intervention group and 27 (33 %) controls were reconnected to the ventilator within 48 h (p = 0.222). The main reasons for failure were respiratory distress (80 and 88 % in the treatment and control group, respectively), hemodynamic impairment (15 and 4 % in the treatment and control group, respectively), neurological deterioration (4 % in the control group only). The duration of mechanical ventilation was of 412 ± 202 h and 402 ± 189 h, in the control and intervention group, respectively. ICU length of stay was on average of 23 days for both groups. ICU mortality was 6 % in the control and 2 % in the intervention group without significant differences.

Conclusion

We found no difference between the two groups under evaluation, with a rate of failure much higher than expected. Consequent to the early interruption, our study results to be underpowered. Based on the results of the present study, a further trial should overall enroll 790 patients.

Trial registration: ACTRN12612000372886

Polymicrobial intensive care unit-acquired pneumonia: prevalence, microbiology and outcome

BACKGROUND

Microbial aetiology of intensive care unit (ICU)-acquired pneumonia (ICUAP) determines antibiotic treatment and outcomes. The impact of polymicrobial ICUAP is not extensively known. We therefore investigated the characteristics and outcomes of polymicrobial aetiology of ICUAP.

METHOD

Patients with ICUAP confirmed microbiologically were prospectively compared according to identification of 1 (monomicrobial) or more (polymicrobial) potentially-pathogenic microorganisms. Microbes usually considered as non-pathogenic were not considered for the etiologic diagnosis. We assessed clinical characteristics, microbiology, inflammatory biomarkers and outcome variables.

RESULTS

Among 441 consecutive patients with ICUAP, 256 (58%) had microbiologic confirmation, and 41 (16%) of them polymicrobial pneumonia. Methicillin-sensitive Staphylococcus aureus, Haemophilus influenzae, and several Enterobacteriaceae were more frequent in polymicrobial pneumonia. Multi-drug and extensive-drug resistance was similarly frequent in both groups. Compared with monomicrobial, patients with polymicrobial pneumonia had less frequently chronic heart disease (6, 15% vs. 71, 33%, p = 0.019), and more frequently pleural effusion (18, 50%, vs. 54, 25%, p = 0.008), without any other significant difference. Appropriate empiric antimicrobial treatment was similarly frequent in the monomicrobial (185, 86%) and the polymicrobial group (39, 95%), as were the initial response to the empiric treatment, length of stay and mortality. Systemic inflammatory response was similar comparing monomicrobial with polymicrobial ICUAP.

CONCLUSION

The aetiology of ICUAP confirmed microbiologically was polymicrobial in 16% cases. Pleural effusion and absence of chronic heart disease are associated with polymicrobial pneumonia. When empiric treatment is frequently appropriate, polymicrobial aetiology does not influence the outcome of ICUAP.

Ventilator-Associated Pneumonia at a Tertiary-Care Center in a Developing Country: Incidence, Microbiology, and Susceptibility Patterns of Isolated Microorganisms

Objective:

Ventilator-associated pneumonia (VAP) complicates the course of up to 24% of intubated patients. Data from the Middle East are scarce. The objective of this study was to evaluate the incidence, microbiology, and antimicrobial susceptibility patterns of isolated microorganisms in VAP in a developing country.

Design:

Prospective observational cohort study.

Setting:

The American University of Beirut Medical Center, a tertiary-care center that serves as a major referral center for Lebanon and neighboring countries.

Patients:

All patients admitted to the intensive care and respiratory care units from March to September 2001, and who had been receiving mechanical ventilation for at least 48 hours, were included in the study. Results of samples submitted for culture were recorded and antimicrobial susceptibility testing of isolated pathogens was performed.

Results:

Seventy patients were entered into the study. The incidence of VAP was 47%. Gram-negative bacilli accounted for 83% of all isolates. The most commonly identified organism was Acinetobacter anitratus, followed by Pseudomonas aeruginosa. Fifty percent of all gram-negative bacterial isolates were classified as antibiotic resistant. Compared with patients without VAP, patients with VAP remained intubated for a longer period and stayed in the intensive care unit longer. VAP was not associated with an increased mortality rate.

Conclusion:

Compared with other studies, the results from this referral center in Lebanon indicate a higher incidence of VAP and a high prevalence of resistant organisms. These data are relevant because they direct the choice of empiric antibiotic therapy for VAP.

Impact of Ventilator-Associated Pneumonia on Resource Utilization and Patient Outcome

Objective:

To assess the effect of ventilator-associated pneumonia on resource utilization, morbidity, and mortality.

Design:

Retrospective matched cohort study based on prospectively collected data.

Setting:

Medical intensive care unit of a university teaching hospital.

Patients:

Case-patients were all patients receiving mechanical ventilation for 48 hours or more who experienced an episode of ventilator-associated pneumonia. Control-patients were matched for number of discharge diagnoses, duration of mechanical support before the onset of pneumonia among case-patients, age, admission diagnosis, gender, and study period.

Results:

One hundred six cases of ventilator-associated pneumonia were identified in 452 patients receiving mechanical ventilation. The matching procedure selected 97 pairs. Length of stay in the intensive care unit and duration of mechanical ventilation were greater among case-patients by a mean of 7.2 days (P< .001) and 5.1 days (P< .001), respectively. Median costs were $24,727 (interquartile range, $18,348 to $39,703) among case-patients and $17,438 (interquartile range, $12,261 to $24,226) among control-patients (P< .001). The attributable mortality rate was 7.3% (P = .26). The attributable extra hospital stay was 10 days with an extra cost of $15,986 per episode of pneumonia.

Conclusion:

Ventilator-associated pneumonia negatively affects patient outcome and represents a significant burden on intensive care unit and hospital resources.

Trends in Ventilator-Associated Pneumonia Rates Within the German Nosocomial Infection Surveillance System (KISS)

Objective.

To investigate trends in ventilator-associated pneumonia (VAP) rates during participation in the German nosocomial infection surveillance system (Krankenhaus-Infektions-Surveillance-System [KISS]).

Methods.

A total of 71 ICUs that began participating in KISS in 1999 or later and continued participation for at least 36 months were selected. Beginning with the first month of participation, the pooled mean rate of VAP in the ICUs was calculated for each year of participation. The incidence densities for the 3 years of participation were compared using the Pearson x2 test. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated. VAP rates were calculated for each ICU and year of participation, and rates for years 1 and 3 were compared using the Wilcoxon test for paired samples.

Results.

Twenty-nine medical-surgical, 18 medical, 20 surgical, 2 neurosurgical, and 2 pediatric ICUs met the selection criteria. Surveillance data were available on 181,275 patients, for whom there were 613,098 patient-days and 224,138 ventilator-days. A total of 2,043 cases of VAP were reported. The ICUs had a pooled VAP rate of 10.5 cases per 1,000 ventilator-days during year 1 of KISS surveillance. In year 2, the rate decreased by 19%, to 8.7 cases per 1,000 ventilator-days (RR, 0.81 [95% CI, 0.73-0.90]). In year 3, the rate decreased by 24% from year 1, to 8.0 cases per 1,000 ventilator-days (RR, 0.76; 95% CI, 0.68-0.85). Both results were significant (P < .001 by the Pearson x2 test). Comparison of the VAP rates of the ICUs did not show a significant difference between years 1 and 3 of KISS participation.

Conclusion.

Surveillance was associated with a significant reduction in the pooled rate of VAP during years 1-3 of KISS participation.

Microbial composition and antibiotic resistance of biofilms recovered from endotracheal tubes of mechanically ventilated patients

In critically ill patients, breathing is impaired and mechanical ventilation, using an endotracheal tube (ET) connected to a ventilator, is necessary. Although mechanical ventilation is a life-saving procedure, it is not without risk. Because of several reasons, a biofilm often forms at the distal end of the ET and this biofilm is a persistent source of bacteria which can infect the lungs, causing ventilator-associated pneumonia (VAP). There is a link between the microbial flora of ET biofilms and the microorganisms involved in the onset of VAP. Culture dependent and independent techniques were already used to identify the microbial flora of ET biofilms and also, the antibiotic resistance of microorganisms obtained from ET biofilms was determined. The ESKAPE pathogens play a dominant role in the onset of VAP and these organisms were frequently identified in ET biofilms. Also, antibiotic resistant microorganisms were frequently present in ET biofilms. Members of the normal oral flora were also identified in ET biofilms but it is thought that these organisms initiate ET biofilm formation and are not directly involved in the development of VAP.

Cytotoxic Virulence Predicts Mortality in Nosocomial Pneumonia Due to Methicillin-Resistant Staphylococcus aureus

The current study identified bacterial factors that may improve management of methicillin-resistant Staphylococcus aureus (MRSA) nosocomial pneumonia. Isolates were obtained from 386 patients enrolled in a randomized, controlled study of antibiotic efficacy. Isolates were screened for production of virulence factors and for vancomycin susceptibility. After adjustment for host factors such as severity of illness and treatment modality, cytotoxic activity was strongly and inversely associated with mortality; however, it had no effect on clinical cure. Isolates having low cytotoxicity, which were derived largely from healthcare-associated clones, exhibited a greater prevalence of vancomycin heteroresistance, and they were recovered more often from patients who were older and frailer. Additionally, a clone with low cytotoxic activity was associated with death and poor clinical improvement. Clone specificity and attenuated virulence appear to be associated with outcome. To our knowledge, these are the first correlations between MRSA virulence and mortality in nosocomial pneumonia.

Automated weaning and SBT systems versus non-automated weaning strategies for weaning time in invasively ventilated critically ill adults

BACKGROUND

Automated systems use closed-loop control to enable ventilators to perform basic and advanced functions while supporting respiration. SmartCare™ is a unique automated weaning system that measures selected respiratory variables, adapts ventilator output to individual patient needs by operationalizing predetermined algorithms and automatically conducts spontaneous breathing trials (SBTs) when predetermined thresholds are met.

OBJECTIVES

The primary objective of this review was to compare weaning time (time from randomization to extubation as defined by study authors) between invasively ventilated critically ill adults weaned by automated weaning and SBT systems versus non-automated weaning strategies.As secondary objectives, we ascertained differences between effects of alternative weaning strategies on clinical outcomes (time to successful extubation, time to first SBT and first successful SBT, mortality, ventilator-associated pneumonia, total duration of ventilation, lengths of intensive care unit (ICU) and hospital stay, use of non-invasive ventilation (NIV), adverse events and clinician acceptance).The third objective of our review was to use subgroup analyses to explore variations in weaning time, length of ICU stay, mortality, ventilator-associated pneumonia, use of NIV and reintubation according to (1) the type of clinician primarily involved in implementing the automated weaning and SBT strategy, (2) the ICU (as a reflection of the population involved) and (3) the non-automated (control) weaning strategy utilized.We conducted a sensitivity analysis to evaluate variations in weaning time based on (4) the methodological quality (low or unclear versus high risk of bias) of the included studies.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) 2013, Issue 5; MEDLINE (1966 to 31 May 2013); EMBASE (1988 to 31 May 2013); the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 31 May 2013), Evidence-Based Medicine Reviews and Ovid HealthSTAR (1999 to 31 May 2013), as well as conference proceedings and trial registration websites; we also contacted study authors and content experts to identify potentially eligible trials.

SELECTION CRITERIA

Randomized and quasi-randomized trials comparing automated weaning and SBT systems versus non-automated weaning strategies in intubated adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and abstracted data according to prespecified criteria. Sensitivity and subgroup analyses were planned to assess the impact on selected outcomes of the following: (1) the type of clinician primarily involved in implementing automated weaning and SBT systems, (2) the ICU (as a reflection of the population involved) and (3) the non-automated (control) weaning strategy utilized.

MAIN RESULTS

We pooled summary estimates from 10 trials evaluating SmartCare™ involving 654 participants. Overall, eight trials were judged to be at low or unclear risk of bias, and two trials were judged to be at high risk of bias. Compared with non-automated strategies, SmartCare™ decreased weaning time (mean difference (MD) -2.68 days, 95% confidence interval (CI) -3.99 to -1.37; P value < 0.0001, seven trials, 495 participants, moderate-quality evidence), time to successful extubation (MD -0.99 days, 95% CI -1.89 to -0.09; P value 0.03, seven trials, 516 participants, low-quality evidence), length of ICU stay (MD -5.70 days, 95% CI -10.54 to -0.85; P value 0.02, six trials, 499 participants, moderate-quality evidence) and proportions of participants receiving ventilation for longer than seven and 21 days (risk ratio (RR) 0.44, 95% CI 0.23 to 0.85; P value 0.01 and RR 0.39, 95% CI 0.18 to 0.86; P value 0.02). SmartCare™ reduced the total duration of ventilation (MD -1.68 days, 95% CI -3.33 to -0.03; P value 0.05, seven trials, 521 participants, low-quality evidence) and the number of participants receiving ventilation for longer than 14 days (RR 0.61, 95% CI 0.37 to 1.00; P value 0.05); however the estimated effects were imprecise. SmartCare™ had no effect on time to first successful SBT, mortality or adverse events, specifically reintubation. Subgroup analysis suggested that trials with protocolized (versus non-protocolized) control weaning strategies reported significantly shorter ICU stays. Sensitivity analysis excluded two trials with high risk of bias and supported a trend toward significant reductions in weaning time favouring SmartCare™.

AUTHORS' CONCLUSIONS

Compared with non-automated weaning strategies, weaning with SmartCare™ significantly decreased weaning time, time to successful extubation, ICU stay and proportions of patients receiving ventilation for longer than seven days and 21 days. It also showed a favourable trend toward fewer patients receiving ventilation for longer than 14 days; however the estimated effect was imprecise. Summary estimates from our review suggest that these benefits may be achieved without increasing the risk of adverse events, especially reintubation; however, the quality of the evidence ranged from low to moderate, and evidence was derived from 10 small randomized controlled trials.

Impact of ventilator associated pneumonia on outcome in patients with chronic obstructive pulmonary disease exacerbation

Background and Objective:

There are sparse data regarding the impact of ventilator-associated pneumonia (VAP) on outcome among patients with chronic obstructive pulmonary disease (COPD) exacerbation.

Materials and Methods:

This retrospective study included patients with COPD exacerbation requiring endotracheal intubation for more than 48 h admitted in a single respiratory unit from January 2008 to December 2009. Records of these patients were checked for the occurrence of VAP.

Results:

One hundred and fifty-three patients required endotracheal intubation for COPD exacerbation during this period. The mean age of this cohort was 61.46 ± 11.3 years. The median duration of COPD was 6 years (range: 1-40). A total of 35 (22.8%) patients developed VAP (early: 9 and late: 26). The risk of mortality was comparable between two groups, that is, patients with and without VAP [odd's ratio (OR)−1.125; 95% confidence interval (CI), 0.622-2.035]. The duration of mechanical ventilation and hospital stay (median ± standard error, 95% CI) was 32 ± 10 (95% CI, 13-51) versus 10 ± 2 (95% CI, 6-14) days; P ≤ 0.001 and 53 ± 26 (95% CI, 3-103) versus 18 ± 7 (95% CI, 5-31) days; P = 0.031, respectively was higher among patients with VAP.

Conclusions:

Our study has shown that VAP leads to increased duration of mechanical ventilation and hospital stay; however, the mortality is not affected.

Determinants of ventilator associated pneumonia and its impact on prognosis: A tertiary care experience

Background:

Ventilator associated pneumonia (VAP) is a major cause of poor outcome among patients in the intensive care units (ICU) world-wide. We sought to determine the factors associated with development of VAP and its prognosis among patients admitted to different ICUs of a Tertiary Care Hospital in India.

Methodology:

We did a matched case control study during October 2009 to May 2011 among patients, ≥18 years with mechanical ventilation. Patients who developed pneumonia after 48 h of ventilation were selected in the case group and those who did not develop pneumonia constituted the control group. Patients’ history, clinical and laboratory findings were recorded and analyzed.

Results:

There were 52 patients included in each group. Among cases, early onset ventilator associated pneumonia (EVAP) occurred in 27 (51.9%) and late onset ventilator associated pneumonia (LVAP) in 25 (48.1%). Drug resistant organisms contributed to 76.9% of VAP. Bacteremia (P = 0.002), prior use of steroid/immunosuppressant (P = 0.004) and re-intubations (P = 0.021) were associated with the occurrence of VAP. The association of Acinetobacter (P = 0.025) and Pseudomonas (P = 0.047) for LVAP was found to be statistically significant. Duration of mechanical ventilation (P = 0.001), ICU stay (P = 0.049) and requirement for tracheostomy (P = 0.043) were significantly higher in VAP. Among each case and control groups, 19 (36.5%) expired.

Conclusion:

We found a higher proportion of LVAP compared with EVAP and a higher proportion of drug resistant organisms among LVAP, especially Pseudomonas and Acinetobacter. Drug resistant Pseudomonas was associated with higher mortality.

Microbiology and prognostic factors of hospital- and community-acquired aspiration pneumonia in respiratory intensive care unit

BACKGROUND

Incidence of aspiration pneumonia in hospital-acquired pneumonia and community-acquired pneumonia is high; however, many features of this disease remain imprecise. Our objective was to characterize the microbial etiology and their antibiotic resistance and to determine the prognostic factors in aspiration pneumonia among patients admitted to a respiratory intensive care unit (RICU).

METHODS

A prospective survey was conducted in 112 patients exhibiting hospital-or community-acquired aspiration pneumonia in the RICU of a provincial general hospital from 2010-2012. Bronchoalveolar lavage sampling was collected, and then followed by standard culture and drug-sensitive test. Risk factors were analyzed by multivariate logistic analysis.

RESULTS

One hundred twenty-eight strains were isolated in 94 patients, gram-negative bacilli (57.8%) was the predominant cultured microorganism, followed by fungus (28.9%) and gram-positive cocci (13.3%). The 5 main isolated bacteria demonstrated high and multiantibiotic resistance. The crude overall mortality was 43.8%, 50%, and 40%, respectively, in hospital- and community-acquired aspiration pneumonia group. Multivariate logistic analysis identified age older than 65 years, use of inotropic support, and ineffective initial therapy as independent risk factors of poor outcome.

CONCLUSIONS

The predominant pathogenic bacteria of aspiration pneumonia in patients admitted to an RICU were antibiotic-resistant bacteria, and effective initial supportive management secured better prognosis.

Cost-Effectiveness Analysis of the Treatment of Ventilator-Associated Pneumonia with Linezolid or Vancomycin in Spain

The aim of this study was to assess the cost-effectiveness of linezolid (LIN) versus vancomycin (VAN) for the treatment of ventilator-associated pneumonia (VAP) using a decision model analysis from the National Health System perspective. Patients and participants comprising four subgroups were analyzed: all, Gram-positive (GP), Staphylococcus aureus (SA), methicillin-resistant SA (MRSA). The treatments were LIN 600 mg i.v., every 12 hours, 10 days and VAN 1,000 mg i.v., every 12 hours 10 days. The primary outcome was the incremental cost-effectiveness of LIN in terms of cost per added quality-adjusted life year (QALY) gained. The secondary outcome was the marginal cost per year of life saved (LYS) generated by using LIN. Clinical cure and survival rates estimates were derived from a retrospective analysis of two trials comparing LIN with VAN. QALY was based on time-trade off study. Resource use and unit costs (Euros 2003) were obtained from Spanish VAP treatment and health cost databases. The additional QALY and LYS per LIN patients were 0.392; 0.688; 0.606; 1.805 and 0.471; 0.829; 0.729; 2.175 respectively, compared with those of VAN in the patients with VAP (all, GP, SA, and MRSA, respectively). The additional costs for LYS with LIN, as compared to VAN were 1,501.31; 827.63; 955.13 and 289.51 Euros, respectively. The additional cost per QALY with LIN was 1,803.87; 997.25; 1,149.00 and 348.85 Euros, respectively.

CONCLUSIONS

LIN was more cost-effective than VAN in the treatment of VAP in Spain, with an additional cost per QALY/LYS gained below the acceptable threshold in Spain of Euros 30,000 for new therapies.

Design and construction of a single tube, quantitative endpoint, LATE-PCR multiplex assay for ventilator-associated pneumonia

AIMS

The goal of this study was to develop a molecular diagnostic multiplex assay for the quantitative detection of microbial pathogens commonly responsible for ventilator-associated pneumonia (VAP) and their antibiotic resistance using linear-after-the-exponential polymerase chain reaction (LATE-PCR).

METHOD AND RESULTS

This multiplex assay was designed for the quantitative detection and identification of pathogen genomic DNA of methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii, Pseudomonas aeruginosa, plus a control target from Lactococcus lactis. After amplification, the single-stranded amplicons were detected simultaneously in the same closed tube by hybridization to low-temperature molecular beacon probes labelled with four differently coloured fluorophores. The resulting hybrids were then analysed by determining the fluorescence intensity of each of the four fluorophores as a function of temperature.

CONCLUSIONS

This LATE-PCR single tube multiplex assay generated endpoint fluorescent contours that allowed identification of all microbial pathogens commonly responsible for VAP, including MRSA. The assay was quantitative, identifying the pathogens present in the sample, no matter whether there were as few as 10 or as many 100 000 target genomes.

SIGNIFICANCE AND IMPACT OF THE STUDY

This assay is rapid, reliable and sensitive and is ready for preclinical testing using samples recovered from patients suffering from ventilator-associated pneumonia.

Chlorhexidine for the prevention of ventilator associated pneumonia in critically ill adults

Nosocomial pneumonia is common in critically ill patients and is associated with high mortality rates. The development of pneumonia in the intensive care unit (ICU) has been associated with bacterial colonisation within the oral cavity and translocation into the respiratory tract. Over recent years, several strategies have been employed and recommended for preventing ventilator associated pneumonia in the ICU. Chlorhexidine, a topical antiseptic, is a promising agent in preventing nosocomial pneumonia because of its wide antimicrobial spectrum of activity, ease of administration, minimal concerns of contributing to bacterial resistance and relatively benign side effect profile. To evaluate the safety and efficacy of chlorhexidine in preventing nosocomial pneumonia in critically ill patients, we conducted a literature search by using PubMed, EMBASE, CINAHL, Web of Science, and MEDLINE databases; Google Scholar, and the Cochrane Central Register of Controlled Trials (1966– February 2013) for relevant studies. Overall, seven clinical trials were identified. These studies showed mixed results and the majority failed to demonstrate a significant reduction in the incidence of nosocomial pneumonia with the use of chlorhexidine. However, the cardiothoracic surgery ICU patient population may benefit from its use. Further studies are warranted to clearly define the role of chlorhexidine in preventing nosocomial pneumonia.

Ventilator-associated pneumonia and ICU mortality in severe ARDS patients ventilated according to a lung-protective strategy

INTRODUCTION

Ventilator-associated pneumonia (VAP) may contribute to the mortality associated with acute respiratory distress syndrome (ARDS). We aimed to determine the incidence, outcome, and risk factors of bacterial VAP complicating severe ARDS in patients ventilated by using a strictly standardized lung-protective strategy.

METHODS

This prospective epidemiologic study was done in all the 339 patients with severe ARDS included in a multicenter randomized, placebo-controlled double-blind trial of cisatracurium besylate in severe ARDS patients. Patients with suspected VAP underwent bronchoalveolar lavage to confirm the diagnosis.

RESULTS

Ninety-eight (28.9%) patients had at least one episode of microbiologically documented bacterial VAP, including 41 (41.8%) who died in the ICU, compared with 74 (30.7%) of the 241 patients without VAP (P = 0.05). After adjustment, age and severity at baseline, but not VAP, were associated with ICU death. Cisatracurium besylate therapy within 2 days of ARDS onset decreased the risk of ICU death. Factors independently associated with an increased risk to develop a VAP were male sex and worse admission Glasgow Coma Scale score. Tracheostomy, enteral nutrition, and the use of a subglottic secretion-drainage device were protective.

CONCLUSIONS

In patients with severe ARDS receiving lung-protective ventilation, VAP was associated with an increased crude ICU mortality which did not remain significant after adjustment.

Rapid and reproducible surveillance for ventilator-associated pneumonia

BACKGROUND

The complexity and subjectivity of ventilator-associated pneumonia (VAP) surveillance limit its value in assessing and comparing quality of care for ventilated patients. A simpler, more quantitative VAP definition may increase utility.

METHODS

We streamlined the Centers for Disease Control and Prevention definition of VAP to increase objectivity and efficiency. Qualitative criteria were replaced with quantitative criteria, and changes in ventilator settings were used to screen patients for worsening oxygenation. We retrospectively compared surveillance time, reproducibility, and outcomes for streamlined versus conventional surveillance among medical and surgical patients on mechanical ventilation in 3 university hospitals.

RESULTS

Application of the streamlined definition was faster (mean 3.5 minutes vs 39.0 minutes per patient) and more objective (interrater reliability κ 0.79 vs 0.45) than the conventional definition. On multivariate analysis, the streamlined definition predicted increases in ventilator days (6.5 days [95% CI, 4.1-10.0] vs 6.4 days [95% CI, 4.7-8.6]), intensive care days (5.6 days [95% CI, 3.2-8.9] vs 6.2 days [95% CI, 4.6-8.2]), and hospital mortality (odds ratio [OR] 0.84 [95% CI, 0.31-2.29] vs OR 0.69 [95% CI, 0.30-1.55]) as effectively as conventional surveillance. The conventional definition was a marginally superior predictor of increased hospital days (5.2 days [95% CI, 3.4-7.6] vs 2.1 days [95% CI, -0.5-5.6]).

CONCLUSIONS

A streamlined version of the VAP definition was faster, more objective, and predicted patients' outcomes almost as effectively as the conventional definition. VAP surveillance using the streamlined method may facilitate more objective and efficient quality assessment for ventilated patients.

Attributable mortality of ventilator-associated pneumonia

PURPOSE OF REVIEW

To critically discuss the attributable mortality of ventilator-associated pneumonia (VAP) and potential sources of variation.

RECENT FINDINGS

The review will cover the available estimates (0-50%). It will also explore the source of variation because of definition of VAP (being lower if inaccurate), case-mix issues (being lower for trauma patients), the severity of underlying illnesses (being maximal when the severity of underlying illness is intermediate), and on the characteristics and the severity of the VAP episode. Another important source of variation is the use of poorly appropriate statistical models (estimates biased by lead time bias and competing events). New extensions of survival models which take into account the time dependence of VAP occurrence and competing risks allow less biased estimation as compared with traditional models.

SUMMARY

Attributable mortality of VAP is about 6%. Accurate diagnostic methods are key to properly estimating it. Traditional statistical models should no longer be used to estimate it. Prevention efforts targeted on patients with intermediate severity may result in the most important outcome benefits.

The role of total bile acid in oral secretions in ventilator-associated pneumonia

PURPOSE

The aim of this study was to investigate the role of inflammatory biomarkers and total bile acid (TBA) in oral secretions in the development of ventilator-associated pneumonia (VAP).

MATERIALS

This prospective study was conducted in an intensive care unit. Oral secretions were collected from mechanically ventilated patients who met the selection criteria for VAP prevention protocol. The levels of interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor α, soluble intercellular adhesion molecule-1, monocyte chemoattractant protein-1, C-reactive protein, surfactant protein D, and TBA in oral secretions were measured and compared between the patients with and those without VAP.

RESULTS

Thirty-nine patients with and 39 patients without VAP were studied. The levels of inflammatory biomarkers in oral secretions showed no significant difference between the 2 groups. However, the patients with VAP had significantly higher values of TBA in oral secretions than did those without VAP (median and 25th-75th interquartile range, 9.59 and 1.37-24.66 μmol/L vs 2.74 and 0.00-8.22 μmol/L; P < .003). No significant correlations were found between TBA and inflammatory biomarkers in oral secretions.

CONCLUSIONS

Duodenogastroesophageal reflux as evidenced by the presence of TBA in oral secretions is common in mechanically ventilated patients and may play a role in the development of VAP.

Automatic control of pressure support for ventilator weaning in surgical intensive care patients

RATIONALE

Despite its ability to reduce overall ventilation time, protocol-guided weaning from mechanical ventilation is not routinely used in daily clinical practice. Clinical implementation of weaning protocols could be facilitated by integration of knowledge-based, closed-loop controlled protocols into respirators.

OBJECTIVES

To determine whether automated weaning decreases overall ventilation time compared with weaning based on a standardized written protocol in an unselected surgical patient population.

METHODS

In this prospective controlled trial patients ventilated for longer than 9 hours were randomly allocated to receive either weaning with automatic control of pressure support ventilation (automated-weaning group) or weaning based on a standardized written protocol (control group) using the same ventilation mode. The primary end point of the study was overall ventilation time.

MEASUREMENTS AND MAIN RESULTS

Overall ventilation time (median [25th and 75th percentile]) did not significantly differ between the automated-weaning (31 [19-101] h; n = 150) and control groups (39 [20-118] h; n = 150; P = 0.178). Patients who underwent cardiac surgery (n = 132) exhibited significantly shorter overall ventilation times in the automated-weaning (24 [18-57] h) than in the control group (35 [20-93] h; P = 0.035). The automated-weaning group exhibited shorter ventilation times until the first spontaneous breathing trial (1 [0-15] vs. 9 [1-51] h; P = 0.001) and a trend toward fewer tracheostomies (17 vs. 28; P = 0.075).

CONCLUSIONS

Overall ventilation times did not significantly differ between weaning using automatic control of pressure support ventilation and weaning based on a standardized written protocol. Patients after cardiac surgery may benefit from automated weaning. Implementation of additional control variables besides the level of pressure support may further improve automated-weaning systems. Clinical trial registered with www.clinicaltrials.gov (NCT 00445289).

Hospital and long-term outcomes of ICU-treated severe community- and hospital-acquired, and ventilator-associated pneumonia patients

BACKGROUND

Our purpose was to analyse the association of pneumonia types with hospital and long-term outcomes of intensive care unit (ICU)-treated pneumonia patients.

METHODS

The occurrence of pneumonia was retrospectively evaluated among prospectively registered patients admitted into a mixed university-level ICU during a 14-month period. Their age, severity of underlying disease, malignancy, immunosuppressive therapy and organ dysfunctions were recorded, as well as the length of hospital stay and short- and long-term mortalities.

RESULTS

There were 117 severe community-acquired pneumonia (SCAP), 66 hospital-acquired pneumonia (HAP) and 25 ventilator-associated pneumonia (VAP) cases among the 817 patients admitted. ICU and hospital mortality did not differ between pneumonia groups. VAP and HAP patients had more malignant underlying diseases than SCAP patients (P < 0.001). HAP patients were older than SCAP and VAP patients (P = 0.023). The admission Acute Physiology and Chronic Health Evaluation II scores did not differ between the groups (P > 0.90). The patients with VAP had higher Sequential Organ Failure Assessment maximum scores compared with patients with SCAP and HAP (P < 0.001). In an adjusted multivariate logistic regression model, there were no significant differences in odds ratios for hospital mortality between the three pneumonia types. Mortality among the hospital survivors during the 12-month follow-up period was 18% (16/89) in the SCAP group, 35% (18/51) in the HAP group and 41% (7/17) in the VAP group (P = 0.023).

CONCLUSION

The type of pneumonia (i.e. SCAP, HAP or VAP) had no significant association with hospital mortality, whereas the SCAP patients had the lowest 1-year mortality.

Is continuous subglottic suctioning cost-effective for the prevention of ventilator-associated pneumonia?

OBJECTIVE

To establish whether continuous subglottic suctioning (CSS) could be cost-effective.

DESIGN

Cost-benefit analysis, based on a hypothetical replacement of conventional ventilation (CV) with CSS.

SETTING

A surgical intensive care unit (SICU) of a tertiary care university hospital in France.

PATIENTS

All consecutive patients receiving ventilation in the SICU in 2006.

METHODS

Efficacy data for CSS were obtained from the literature and applied to the SICU of our hospital. Costs for CV and CSS were provided by the hospital pharmacy; costs for ventilator-associated pneumonia (VAP) were obtained from the literature. The cost per averted VAP episode was calculated, and a sensitivity analysis was performed on VAP incidence and on the number of tubes required for each patient.

RESULTS

At our SICU in 2006, 416 patients received mechanical ventilation for 3,487 ventilation-days, and 32 VAP episodes were observed (7.9 episodes per 100 ventilated patients; incidence density, 9.2 episodes per 10,000 ventilation-days). Based on the hypothesis of a 29% reduction in the risk of VAP with CSS than CV, 9 VAP episodes could have been averted. The additional cost of CSS for 2006 was estimated to be €10,585.34. The cost per averted VAP episode was €1,176.15. Assuming a VAP cost of €4,387, a total of 3 averted VAP episodes would neutralize the additional cost. For a low VAP incidence of 6.6%, the cost per averted VAP would be €1,323. If each patient required 2 tubes during ventilation, the cost would be €1,383.69 per averted VAP episode.

CONCLUSION

Replacement of CV with CSS was cost-effective even when assuming the most pessimistic scenario of VAP incidence and costs.

Biomarkers for ventilator-associated pneumonia: review of the literature

OBJECTIVE

Ventilator-associated pneumonia (VAP) contributes significantly to morbidity and mortality in critically ill patients, but it can be difficult to diagnose. Clinical criteria, Clinical Pulmonary Infection Score, and quantitative culture of bronchoalveolar lavage have been used to distinguish between patients who are likely positive (sensitivity) and patients who are likely negative (specificity). Despite these test methods, patients continue to be misclassified. False-positive results may lead to inappropriate antibiotic use in patients. For those misclassified as test negative, appropriate treatment may be delayed. Biomarkers have been suggested as another method to enhance the ability to predict VAP. This article analyzes the evidence for the usefulness of 3 biomarkers that have been proposed as possible biomarkers of VAP: soluble triggering receptor expressed on myeloid type 1 cells, procalcitonin, and C-reactive protein.

METHODS

A Medline search was conducted for the years between 1990 and 2009 to locate articles on the subject of biomarkers for predicting VAP in critically ill adult patients.

RESULTS

Analysis of the literature does not currently support a clinical role for these biomarkers in predicting VAP. Variations in the diagnostic methods, antimicrobial use, cutoff values, and patient populations limit comparisons among the studies.

CONCLUSION

Recommendations are offered to strengthen and standardize methods in future studies to clarify the utility of biomarkers for predicting VAP in specific patient populations.

Impact of nonexacerbated COPD on mortality in critically ill patients

BACKGROUND

The real contribution of nonexacerbated COPD to mortality has not been studied. The aim of our study was to evaluate the impact of nonexacerbated COPD on mortality in patients requiring mechanical ventilation (MV).

METHODS

This prospective, observational study included critically ill, ventilated patients without evidence of respiratory infection. Patients with COPD comprised the study group. Clinical and demographics variables were recorded. The main end point was ICU mortality.

RESULTS

Of the 235 patients included, 60 (25.5%) intubated patients had COPD. The remaining 175 (74.5%) comprised the control group. Those with COPD were more often medical patients who were older and had a higher number of comorbidities and a higher APACHE (Acute Physiology and Chronic Health Evaluation) II score than intubated patients without COPD (P < .05). The overall ICU mortality was 26.3% (62/235) and significantly higher in patients with nonexacerbated COPD (36.7% vs 22.9%, P < .05), with an attributable mortality to COPD of 13.8%. Incidence of ventilator-associated pneumonia was not significantly different between patients with nonexacerbated COPD (11.9/1,000 MV days) and without COPD (16.0/1,000 MV days; P = .40). In the multivariate analysis, only COPD (hazard ratio [HR], 2.1; 95% CI, 1.10-3.94), shock at ICU admission (HR, 2.0; 95% CI, 1.01-4.01), and medical condition (HR, 1.7; 95% CI, 1.01-3.18) were independently associated with mortality.

CONCLUSIONS

Intubated patients with nonexacerbated COPD were not exposed to a higher risk of ventilator-associated pneumonia but had a higher rate of mortality.

Use of weaning protocols for reducing duration of mechanical ventilation in critically ill adult patients: Cochrane systematic review and meta-analysis

OBJECTIVE

To investigate the effects of weaning protocols on the total duration of mechanical ventilation, mortality, adverse events, quality of life, weaning duration, and length of stay in the intensive care unit and hospital.

DESIGN

Systematic review.

DATA SOURCES

Cochrane Central Register of Controlled Trials, Medline, Embase, CINAHL, LILACS, ISI Web of Science, ISI Conference Proceedings, Cambridge Scientific Abstracts, and reference lists of articles. We did not apply language restrictions. Review methods We included randomised and quasi-randomised controlled trials of weaning from mechanical ventilation with and without protocols in critically ill adults. Data selection Three authors independently assessed trial quality and extracted data. A priori subgroup and sensitivity analyses were performed. We contacted study authors for additional information.

RESULTS

Eleven trials that included 1971 patients met the inclusion criteria. Compared with usual care, the geometric mean duration of mechanical ventilation in the weaning protocol group was reduced by 25% (95% confidence interval 9% to 39%, P=0.006; 10 trials); the duration of weaning was reduced by 78% (31% to 93%, P=0.009; six trials); and stay in the intensive care unit length by 10% (2% to 19%, P=0.02; eight trials). There was significant heterogeneity among studies for total duration of mechanical ventilation (I(2)=76%, P<0.01) and duration of weaning (I(2)=97%, P<0.01), which could not be explained by subgroup analyses based on type of unit or type of approach.

CONCLUSION

There is evidence of a reduction in the duration of mechanical ventilation, weaning, and stay in the intensive care unit when standardised weaning protocols are used, but there is significant heterogeneity among studies and an insufficient number of studies to investigate the source of this heterogeneity. Some studies suggest that organisational context could influence outcomes, but this could not be evaluated as it was outside the scope of this review.

Paradoxical ventilator associated pneumonia incidences among selective digestive decontamination studies versus other studies of mechanically ventilated patients: benchmarking the evidence base

Introduction

Selective digestive decontamination (SDD) appears to have a more compelling evidence base than non-antimicrobial methods for the prevention of ventilator associated pneumonia (VAP). However, the striking variability in ventilator associated pneumonia-incidence proportion (VAP-IP) among the SDD studies remains unexplained and a postulated contextual effect remains untested for.

Methods

Nine reviews were used to source 45 observational (benchmark) groups and 137 component (control and intervention) groups of studies of SDD and studies of three non-antimicrobial methods of VAP prevention. The logit VAP-IP data were summarized by meta-analysis using random effects methods and the associated heterogeneity (tau²) was measured. As group level predictors of logit VAP-IP, the mode of VAP diagnosis, proportion of trauma admissions, the proportion receiving prolonged ventilation and the intervention method under study were examined in meta-regression models containing the benchmark groups together with either the control (models 1 to 3) or intervention (models 4 to 6) groups of the prevention studies.

Results

The VAP-IP benchmark derived here is 22.1% (95% confidence interval; 95% CI; 19.2 to 25.5; tau² 0.34) whereas the mean VAP-IP of control groups from studies of SDD and of non-antimicrobial methods, is 35.7 (29.7 to 41.8; tau² 0.63) versus 20.4 (17.2 to 24.0; tau² 0.41), respectively (P < 0.001). The disparity between the benchmark groups and the control groups of the SDD studies, which was most apparent for the highest quality studies, could not be explained in the meta-regression models after adjusting for various group level factors. The mean VAP-IP (95% CI) of intervention groups is 16.0 (12.6 to 20.3; tau² 0.59) and 17.1 (14.2 to 20.3; tau² 0.35) for SDD studies versus studies of non-antimicrobial methods, respectively.

Conclusions

The VAP-IP among the intervention groups within the SDD evidence base is less variable and more similar to the benchmark than among the control groups. These paradoxical observations cannot readily be explained. The interpretation of the SDD evidence base cannot proceed without further consideration of this contextual effect.