Ventilator-associated pneumonia and mortality: a systematic review of observational studies

Epidemiology and Burden of Ventilator-Associated Pneumonia among Adult Intensive Care Unit Patients: A Portuguese, Multicenter, Retrospective Study (eVAP-PT Study)

Ventilator-associated pneumonia (VAP) is a prevailing nosocomial infection in critically ill patients requiring invasive mechanical ventilation (iMV). The impact of VAP is profound, adversely affecting patient outcomes and placing a significant burden on healthcare resources. This study assessed for the first time the contemporary VAP epidemiology in Portugal and its burden on the healthcare system and clinical outcomes. Additionally, resource consumption (duration of iMV, intensive care unit (ICU), hospital length of stay (LOS)) and empirical antimicrobial therapy were also evaluated. This multicenter, retrospective study included patients admitted to the hospital between July 2016 and December 2017 in a participating ICU, who underwent iMV for at least 48 h. Patients with a VAP diagnosis were segregated for further analysis (n = 197). Control patients, ventilated for >48 h but without a VAP diagnosis, were also included in a 1:1 ratio. Cumulative VAP incidence was computed. All-cause mortality was assessed at 28, 90, and 365 days after ICU admission. Cumulative VAP incidence was 9.2% (95% CI 8.0-10.5). The all-cause mortality rate in VAP patients was 24.9%, 34.0%, and 40.6%, respectively, and these values were similar to those observed in patients without VAP diagnosis. Further, patients with VAP had significantly longer ICU (27.5 vs. 11.0 days, p < 0.001) and hospital LOS (61 vs. 35.9 days, p < 0.001), more time under iMV (20.7 vs. 8.0 days, p < 0.001) and were more often subjected to tracheostomy (36.5 vs. 14.2%; p < 0.001). Patients with VAP who received inappropriate empirical antimicrobials had higher 28-day mortality, 34.3% vs. 19.5% (odds ratio 2.16, 95% CI 1.10-4.23), although the same was not independently associated with 1-year all-cause mortality (p = 0.107). This study described the VAP impact and burden on the Portuguese healthcare system, with approximately 9% of patients undergoing iMV for >48 h developing VAP, leading to increased resource consumption (longer ICU and hospital LOS). An unexpectedly high incidence of inappropriate, empirical antimicrobial therapy was also noted, being positively associated with a higher mortality risk of these patients. Knowledge of the Portuguese epidemiology characterization of VAP and its multidimensional impact is essential for efficient treatment and optimized long-term health outcomes of these patients.

Candida and the Gram-positive trio: testing the vibe in the ICU patient microbiome using structural equation modelling of literature derived data

Background

Whether Candida interacts with Gram-positive bacteria, such as Staphylococcus aureus, coagulase negative Staphylococci (CNS) and Enterococci, to enhance their invasive potential from the microbiome of ICU patients remains unclear. Several effective anti-septic, antibiotic, anti-fungal, and non-decontamination based interventions studied for prevention of ventilator associated pneumonia (VAP) and other ICU acquired infections among patients receiving prolonged mechanical ventilation (MV) are known to variably impact Candida colonization. The collective observations within control and intervention groups from numerous ICU infection prevention studies enables tests of these postulated microbial interactions in the clinical context.

Methods

Four candidate generalized structural equation models (GSEM), each with Staphylococcus aureus, CNS and Enterococci colonization, defined as latent variables, were confronted with blood culture and respiratory tract isolate data derived from 460 groups of ICU patients receiving prolonged MV from 283 infection prevention studies.

Results

Introducing interaction terms between Candida colonization and each of S aureus (coefficient + 0.40; 95% confidence interval + 0.24 to + 0.55), CNS (+ 0.68; + 0.34 to + 1.0) and Enterococcal (+ 0.56; + 0.33 to + 0.79) colonization (all as latent variables) improved the fit for each model. The magnitude and significance level of the interaction terms were similar to the positive associations between exposure to topical antibiotic prophylaxis (TAP) on Enterococcal (+ 0.51; + 0.12 to + 0.89) and Candida colonization (+ 0.98; + 0.35 to + 1.61) versus the negative association of TAP with S aureus (− 0.45; − 0.70 to − 0.20) colonization and the negative association of anti-fungal exposure and Candida colonization (− 1.41; − 1.6 to − 0.72).

Conclusions

GSEM modelling of published ICU infection prevention data enables the postulated interactions between Candida and Gram-positive bacteria to be tested using clinically derived data. The optimal model implies interactions occurring in the human microbiome facilitating bacterial invasion and infection. This interaction might also account for the paradoxically high bacteremia incidences among studies of TAP in ICU patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12982-022-00116-9.

GSEM modelling of published ICU infection prevention data from > 250 studies enables a test of and provides support to the interaction between Candida and Gram-positive bacteria.

The various ICU infection prevention interventions may each broadly impact the patient microbiome.

Probiotics in Critically Ill Patients: An Umbrella Review

Objectives

Data sources

Study selection

Data extraction

Data synthesis

Conclusion

How to cite this article

Relationship between ventilator-associated pneumonia and mortality in COVID-19 patients: a planned ancillary analysis of the coVAPid cohort

Background

Patients with SARS-CoV-2 infection are at higher risk for ventilator-associated pneumonia (VAP). No study has evaluated the relationship between VAP and mortality in this population, or compared this relationship between SARS-CoV-2 patients and other populations. The main objective of our study was to determine the relationship between VAP and mortality in SARS-CoV-2 patients.

Methods

Planned ancillary analysis of a multicenter retrospective European cohort. VAP was diagnosed using clinical, radiological and quantitative microbiological criteria. Univariable and multivariable marginal Cox’s regression models, with cause-specific hazard for duration of mechanical ventilation and ICU stay, were used to compare outcomes between study groups. Extubation, and ICU discharge alive were considered as events of interest, and mortality as competing event.

Findings

Of 1576 included patients, 568 were SARS-CoV-2 pneumonia, 482 influenza pneumonia, and 526 no evidence of viral infection at ICU admission. VAP was associated with significantly higher risk for 28-day mortality in SARS-CoV-2 group (adjusted HR 1.65 (95% CI 1.11–2.46), p = 0.013), but not in influenza (1.74 (0.99–3.06), p = 0.052), or no viral infection groups (1.13 (0.68–1.86), p = 0.63). VAP was associated with significantly longer duration of mechanical ventilation in the SARS-CoV-2 group, but not in the influenza or no viral infection groups. VAP was associated with significantly longer duration of ICU stay in the 3 study groups. No significant difference was found in heterogeneity of outcomes related to VAP between the 3 groups, suggesting that the impact of VAP on mortality was not different between study groups.

Interpretation

VAP was associated with significantly increased 28-day mortality rate in SARS-CoV-2 patients. However, SARS-CoV-2 pneumonia, as compared to influenza pneumonia or no viral infection, did not significantly modify the relationship between VAP and 28-day mortality.

Clinical trial registration

The study was registered at ClinicalTrials.gov, number NCT04359693.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03588-4.

Candida-Acinetobacter-Pseudomonas Interaction Modelled within 286 ICU Infection Prevention Studies

BACKGROUND

Whether Candida interacts to enhance the invasive potential of Acinetobacter and Pseudomonas bacteria cannot be resolved within individual studies. There are several anti-septic, antibiotic, anti-fungal, and non-decontamination-based interventions to prevent ICU acquired infection. These effective prevention interventions would be expected to variably impact Candida colonization. The collective observations within control and intervention groups from numerous ICU infection prevention studies simulates a multi-centre natural experiment with which to evaluate Candida, Acinetobacter and Pseudomonas interaction (CAPI).

METHODS

Eight Candidate-generalized structural equation models (GSEM), with Candida, Pseudomonas and Acinetobacter colonization as latent variables, were confronted with blood culture and respiratory tract isolate data derived from >400 groups derived from 286 infection prevention studies.

RESULTS

Introducing an interaction term between Candida colonization and each of Pseudomonas and Acinetobacter colonization improved model fit in each case. The size of the coefficients (and 95% confidence intervals) for these interaction terms in the optimal Pseudomonas (+0.33; 0.22 to 0.45) and Acinetobacter models (+0.32; 0.01 to 0.5) were similar to each other and similar in magnitude, but contrary in direction, to the coefficient for exposure to topical antibiotic prophylaxis (TAP) on Pseudomonas colonization (-0.45; -0.71 to -0.2). The coefficient for exposure to topical antibiotic prophylaxis on Acinetobacter colonization was not significant.

CONCLUSIONS

GSEM modelling of published ICU infection prevention data supports the CAPI concept. The CAPI model could account for some paradoxically high Acinetobacter and Pseudomonas infection incidences, most apparent among the concurrent control groups of TAP studies.

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).

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.

Discrepancies in Control Group Mortality Rates Within Studies Assessing Topical Antibiotic Strategies to Prevent Ventilator-Associated Pneumonia: An Umbrella Review

Supplemental Digital Content is available in the text.

Objectives:

To test the postulate that concurrent control patients within ICUs studying topical oropharyngeal antibiotics to prevent ventilator-associated pneumonia and mortality would experience spillover effects from the intervention.

Data Sources:

Studies cited in 15 systematic reviews of various topical antibiotic and other infection prevention interventions among ICU patients.

Study Selection:

Studies of topical antibiotics, stratified into concurrent control versus nonconcurrent control designs. Studies of nondecontamination-based infection prevention interventions provide additional points of reference. Studies with no infection prevention intervention provide the mortality benchmark. Data from additional studies and data reported as intention to treat were used within sensitivity tests.

Data Extraction:

Mortality incidence proportion data, mortality census, study characteristics, group mean age, ICU type, and study publication year.

Data Synthesis:

Two-hundred six studies were included. The summary effect sizes for ventilator-associated pneumonia and mortality prevention derived in the 15 systematic reviews were replicated. The mean ICU mortality incidence for concurrent control groups of topical antibiotic studies (28.5%; 95% CI, 25.0–32.3; n = 41) is higher versus the benchmark (23.7%; 19.2–28.5%; n = 34), versus nonconcurrent control groups (23.5%; 19.3–28.3; n = 14), and versus intervention groups (24.4%; 22.1–26.9; n = 62) of topical antibiotic studies. In meta-regression models adjusted for group-level characteristics such as group mean age and publication year, concurrent control group membership within a topical antibiotic study remains associated with higher mortality (p = 0.027), whereas other group memberships, including membership within an antiseptic study, are each neutral (p = not significant).

Conclusions:

Within topical antibiotic studies, the concurrent control group mortality incidence proportions are inexplicably high, whereas the intervention group mortality proportions are paradoxically similar to a literature-derived benchmark. The unexplained ventilator-associated pneumonia and mortality excess in the concurrent control groups implicates spillover effects within studies of topical antibiotics. The apparent ventilator-associated pneumonia and mortality prevention effects require cautious interpretation.

Predictors and microbiology of ventilator-associated pneumonia among patients with exacerbation of chronic obstructive pulmonary disease

BACKGROUND

Understanding the risk factors and microbiology of ventilator-associated pneumonia (VAP) among patients with chronic obstructive pulmonary disease (COPD) is important for the application of preventive and therapeutic interventions. Therefore, this study was planned to assess the clinical predictors and microbiological features of VAP among COPD patients.

MATERIALS AND METHODS

This prospective study involved patients with exacerbation of COPD who required mechanical ventilation and admitted in respiratory intensive care unit at a tertiary care teaching hospital. Various baseline demographic and clinical features were compared between patients with VAP and without VAP. Univariate and multivariable analyses were done to assess the impact of demographic and clinical features on the development of VAP.

RESULTS

The study included 100 intubated patients with age (mean ± standard deviation [SD]) of 62.45 ± 8.32 years, duration (median) of COPD of 6 years, and Acute Physiology, Age, and Chronic Health Evaluation score (mean ± SD) of 18.60 ± 4.30. In this cohort, 17 patients developed VAP. Multivariable analysis showed that Sequential Organ Failure Assessment (SOFA) score at admission, re-intubation, and history of previous hospitalization were independent predictors of VAP with odds ratio (95% confidence interval) of 2.70 (1.24, 5.63; P = 0.012), 66.96 (4.86, 922.72; P = 0.002), and 35.92 (2.84, 454.63; P = 0.006), respectively. Acinetobacter baumannii was the most frequent organism (n = 8; 47%), followed by Klebsiella pneumoniae (n = 5; 29%), Pseudomonas aeruginosa (n = 1; 6%), and Enterobacter spp. (n = 1; 6%). All organisms were multidrug resistant (MDR).

CONCLUSIONS

SOFA score at admission, re-intubation, and history of previous hospitalization were independent predictors of VAP. Antimicrobial therapy for VAP should cover MDR Gram-negative organisms.

Influence of Anesthesia Type on Outcomes after Endovascular Treatment in Acute Ischemic Stroke: Meta-Analysis

PURPOSE

To assess clinical and angiographic outcomes after endovascular treatment (EVT) in ischemic stroke patients according to anesthesia types (general anesthesia vs. conscious sedation).

MATERIALS AND METHODS

A systematic literature review through an online data base between January 1990 and September 2017 was performed. A fixed effect model was used in cases of <50% heterogeneity. The primary outcomes were good clinical outcome at the 3-month follow-up and successful recanalization. A meta-regression analysis was done to estimate primary outcomes of log odds ratio (OR) on onset-to-puncture time (OTP) differences. Publication bias was determined using Begg's funnel plot and additional the Trim and Fill method.

RESULTS

Sixteen articles including 2,662 patients (general anesthesia, n=1,275; conscious sedation, n=1,387) were included. General anesthesia significantly decreased good outcomes than conscious sedation (OR, 0.564; 95% confidence interval [CI], 0.354-0.899). However, outcomes did not differ significantly in randomized controlled trials (RCTs; OR, 1.101; 95% CI, 0.395-3.071). Anesthesia type was not associated with successful recanalization (OR, 0.985; 95% CI, 0.787-1.233). General anesthesia increased the risk of mortality (OR, 1.532; 95% CI, 1.187-1.976) and pneumonia (OR, 1.613; 95% CI, 1.172-2.221), but not symptomatic intracranial hemorrhage (OR, 1.125; 95% CI, 0.767-1.652). The meta-regression analysis showed no linear relationship between OTP differences and log OR of good outcome (coefficient, 0.0004; P=0.95) or successful recanalization (coefficient, 0.0005; P=0.94), respectively.

CONCLUSION

General anesthesia seemed to be associated with adverse clinical outcome after EVT. However, its efficacy was not demonstrated in RCTs. Successful recanalization did not differ according to anesthesia type. Studies using individual patient data based on further RCTs are necessary to elucidate anesthesia effect on procedural and clinical outcomes.

Impact of subglottic secretion drainage on microaspiration in critically ill patients: a prospective observational study

Background

Microaspiration is a major factor in ventilator-associated pneumonia (VAP) pathophysiology. Subglottic secretion drainage (SSD) aims at reducing its incidence.

Methods

Single-center prospective observational study, performed in a French intensive care unit (ICU) from March 2012 to April 2013, including adult patients mechanically ventilated for at least 24 hours divided in two groups: patients in the SSD group intubated using tracheal tubes allowing SSD and patients in the control group intubated with standard tracheal tubes. Pepsin and salivary amylase concentrations were measured for 24 hours in all tracheal aspirates. Primary objective was to determine the impact of SSD on gastric or oropharyngeal microaspiration using pepsin or amylase concentration in tracheal aspirates.

Results

Fifty-five patients were included in the SSD group and 45 in the control group. No difference was found between groups regarding the incidence of microaspiration defined as at least one tracheal aspirate positive for either pepsin or amylase [49 (89%) vs. 37 (82%), P=0.469]. Percentage of patients with VAP [16 (29%) vs. 11 (24%), P=0.656], ventilator-associated tracheobronchitis (VAT) [7 (13%) vs. 4 (9%), P=0.750] or early airway colonization [15 (35%) vs. 8 (18%), P=0.219] were not significantly different in study groups.

Conclusions

SSD did not reduce the incidence of microaspiration, VAP, VAT or airway colonization in this observational study.

Relationship between digestive tract colonization and subsequent ventilator-associated pneumonia related to ESBL-producing Enterobacteriaceae

BACKGROUND

Ventilator-associated pneumonia (VAP) is the most common ICU-acquired infection. Recently, the incidence of extended-spectrum beta-lactamase producing Enterobacteriaceae (ESBLE) has substantially increased in critically ill patients. Identifying patients at risk for VAP related to ESBLE could be helpful to improve the rate of appropriate initial antibiotic treatment, and to reduce unnecessary exposure to carbapenems. The primary objective was to identify risk factors for VAP related to ESBLE. Secondary objective was to determine the impact of ESBLE on outcome in VAP patients.

METHODS

This retrospective study was conducted in a single mixed intensive care unit (ICU), during a 4-year period. All patients with confirmed VAP were included. VAP was defined using clinical, radiologic and quantitative microbiological data. VAP first episodes were prospectively identified using the continuous surveillance data. Exposure to different risk factors was taken into account until the diagnosis of ESBLE VAP or until ICU discharge, in patients with ESBLE VAP and VAP related to other bacteria, respectively. In all patients, routine screening for ESBLE (rectal swab) was performed at ICU admission and once a week. Patients with ESBLE VAP were compared with those with VAP related to other bacteria using univariate analysis. All significant factors were included in the multivariate logistic regression model.

RESULTS

Among the 410 patients with VAP, 43 (10.5%) had ESBLE VAP, 76 (19%) patients had polymicrobial VAP and 189 (46%) had VAP related to multidrug resistant bacteria. Multivariate analysis identified prior ESBLE colonization of the digestive tract as the only independent risk factor for ESBLE VAP (OR [95% CI] = 23 [10-55], p < 0.001). Whilst the positive predictive value of ESBLE digestive colonization was low (43.6%), its negative predictive value was excellent (97.3%) in predicting ESBLE VAP. Duration of mechanical ventilation (median [IQR], 28 [18,42] vs 23 [15,42] d, p = 0.4), length of ICU stay (31 [19,53] vs 29 [18,46] d, p = 0.6), and mortality rates (55.8% vs 50%, p = 0.48) were similar in ESBLE VAP, compared with VAP related to other bacteria.

CONCLUSION

Digestive tract colonization related to ESBLE is independently associated with ESBLE VAP. Its excellent negative predictive value suggests that patients without ESBLE colonization should not receive carbapenems as part of their initial empirical treatment to cover ESBLE.

Effects of chlorhexidine gluconate oral care on hospital mortality: a hospital-wide, observational cohort study

Purpose

Chlorhexidine oral care is widely used in critically and non-critically ill hospitalized patients to maintain oral health. We investigated the effect of chlorhexidine oral care on mortality in a general hospitalized population.

Methods

In this single-center, retrospective, hospital-wide, observational cohort study we included adult hospitalized patients (2012–2014). Mortality associated with chlorhexidine oral care was assessed by logistic regression analysis. A threshold cumulative dose of 300 mg served as a dichotomic proxy for chlorhexidine exposure. We adjusted for demographics, diagnostic category, and risk of mortality expressed in four categories (minor, moderate, major, and extreme).

Results

The study cohort included 82,274 patients of which 11,133 (14%) received chlorhexidine oral care. Low-level exposure to chlorhexidine oral care (≤ 300 mg) was associated with increased risk of death [odds ratio (OR) 2.61; 95% confidence interval (CI) 2.32–2.92]. This association was stronger among patients with a lower risk of death: OR 5.50 (95% CI 4.51–6.71) with minor/moderate risk, OR 2.33 (95% CI 1.96–2.78) with a major risk, and a not significant OR 1.13 (95% CI 0.90–1.41) with an extreme risk of mortality. Similar observations were made for high-level exposure (> 300 mg). No harmful effect was observed in ventilated and non-ventilated ICU patients. Increased risk of death was observed in patients who did not receive mechanical ventilation and were not admitted to ICUs. The adjusted number of patients needed to be exposed to result in one additional fatality case was 47.1 (95% CI 45.2–49.1).

Conclusions

These data argue against the indiscriminate widespread use of chlorhexidine oral care in hospitalized patients, in the absence of proven benefit in specific populations.

Electronic supplementary material

The online version of this article (10.1007/s00134-018-5171-3) contains supplementary material, which is available to authorized users.

Impact of immunosuppression on incidence, aetiology and outcome of ventilator-associated lower respiratory tract infections

The aim of this planned analysis of the prospective multinational TAVeM database was to determine the incidence, aetiology and impact on outcome of ventilator-associated lower respiratory tract infections (VA-LRTI) in immunocompromised patients.All patients receiving mechanical ventilation for >48 h were included. Immunocompromised patients (n=663) were compared with non-immunocompromised patients (n=2297).The incidence of VA-LRTI was significantly lower among immunocompromised than among non-immunocompromised patients (16.6% versus 24.2%; sub-hazard ratio 0.65, 95% CI 0.53-0.80; p<0.0001). Similar results were found regarding ventilator-associated tracheobronchitis (7.3% versus 11.6%; sub-hazard ratio 0.61, 95% CI 0.45-0.84; p=0.002) and ventilator-associated pneumonia (9.3% versus 12.7%; sub-hazard ratio 0.72, 95% CI 0.54-0.95; p=0.019). Among patients with VA-LRTI, the rates of multidrug-resistant bacteria (72% versus 59%; p=0.011) and intensive care unit mortality were significantly higher among immunocompromised than among non-immunocompromised patients (54% versus 30%; OR 2.68, 95% CI 1.78-4.02; p<0.0001). In patients with ventilator-associated pneumonia, mortality rates were higher among immunocompromised than among non-immunocompromised patients (64% versus 34%; p<0.001).Incidence of VA-LRTI was significantly lower among immunocompromised patients, but it was associated with a significantly higher mortality rate. Multidrug-resistant pathogens were more frequently found in immunocompromised patients with VA-LRTI.

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.

Risk factors for ventilator-associated pneumonia in trauma patients: A descriptive analysis

BACKGROUND

We sought to evaluate the risk factors for developing ventilator-associated pneumonia (VAP) and whether the location of intubation posed a risk in trauma patients.

METHODS

Data were retrospectively reviewed for adult trauma patients requiring intubation for > 48 hours, admitted between 2010 and 2013. Patients' demographics, clinical presentations and outcomes were compared according to intubation location (prehospital intubation [PHI] vs. trauma room [TRI]) and presence vs. absence of VAP. Multivariate regression analysis was performed to identify predictors of VAP.

RESULTS

Of 471 intubated patients, 332 patients met the inclusion criteria (124 had PHI and 208 had TRI) with a mean age of 30.7±14.8 years. PHI group had lower GCS (P=0.001), respiratory rate (P=0.001), and higher frequency of head (P=0.02) and chest injuries (P=0.04). The rate of VAP in PHI group was comparable to the TRI group (P=0.60). Patients who developed VAP were 6 years older, had significantly lower GCS and higher ISS, head AIS, and higher rates of polytrauma. The overall mortality was 7.5%, and was not associated with intubation location or pneumonia rates. In the early-VAP group, gram-positive pathogens were more common, while gram-negative microorganisms were more frequently encountered in the late VAP group. Logistic regression analysis and modeling showed that the impact of the location of intubation in predicting the risk of VAP appeared only when chest injury was included in the models.

CONCLUSION

In trauma, the risk of developing VAP is multifactorial. However, the location of intubation and presence of chest injury could play an important role.

Perioperative respiratory complications: current evidence and strategy discussed in 2017 JA symposium

Respiratory management during general anesthesia aims to safely secure the airway and maintain adequate ventilation to deliver oxygen to the vital organs, maintaining homeostasis even during surgery. Despite its clinical importance, anesthesiologists often encounter difficulties in properly managing respiration during the perioperative period, leading to severe respiratory complications. In this year's JA symposium, 5 editorial board members of Journal of Anesthesia (JA) who are experts in the field of respiratory management in anesthesia discussed the following topics: quitting smoking before surgery: exposure to passive smoke is damaging to children, ventilator-associated pneumonia, high inspiratory oxygen concentration and lung injury, aspiration pneumonia, and postoperative respiratory management strategy in patients with obstructive sleep apnea. We hope that this special article regarding this year's JA symposium may be useful for JA readers to manage clinical anesthesia on a daily basis.

Ventilator-associated pneumonia: the influence of bacterial resistance, prescription errors, and de-escalation of antimicrobial therapy on mortality rates

Ventilator-associated pneumonia is the most prevalent nosocomial infection in intensive care units and is associated with high mortality rates (14–70%).

Aim

This study evaluated factors influencing mortality of patients with Ventilator-associated pneumonia (VAP), including bacterial resistance, prescription errors, and de-escalation of antibiotic therapy.

Methods

This retrospective study included 120 cases of Ventilator-associated pneumonia admitted to the adult adult intensive care unit of the Federal University of Uberlândia. The chi-square test was used to compare qualitative variables. Student's t-test was used for quantitative variables and multiple logistic regression analysis to identify independent predictors of mortality.

Findings

De-escalation of antibiotic therapy and resistant bacteria did not influence mortality. Mortality was 4 times and 3 times higher, respectively, in patients who received an inappropriate antibiotic loading dose and in patients whose antibiotic dose was not adjusted for renal function. Multiple logistic regression analysis revealed the incorrect adjustment for renal function was the only independent factor associated with increased mortality.

Conclusion

Prescription errors influenced mortality of patients with Ventilator-associated pneumonia, underscoring the challenge of proper Ventilator-associated pneumonia treatment, which requires continuous reevaluation to ensure that clinical response to therapy meets expectations.

Impact of selective digestive decontamination on respiratory tract Candida among patients with suspected ventilator-associated pneumonia. A meta-analysis

The purpose here is to establish the incidence of respiratory tract colonization with Candida (RT Candida) among ICU patients receiving mechanical ventilation within studies in the literature. Also of interest is its relationship with candidemia and the relative importance of topical antibiotic (TA) use as within studies of selective digestive decontamination (SDD) versus other candidate risk factors towards it. The incidence of RT Candida was extracted from component (control and intervention) groups decanted from studies of various TA and non-TA ICU infection prevention methods with summary estimates derived using random effects. A benchmark RT Candida incidence to provide overarching calibration was derived using (observational) groups from studies without any prevention method under study. A multi-level regression model of group level data was undertaken using generalized estimating equation (GEE) methods. RT Candida data were sourced from 113 studies. The benchmark RT Candida incidence is 1.3; 0.9-1.8 % (mean and 95 % confidence intervals). Membership of a concurrent control group of a study of SDD (p = 0.02), the group-wide presence of candidemia risk factors (p < 0.001), and proportion of trauma admissions (p = 0.004), but neither the year of study publication, nor membership of any other component group, nor the mode of respiratory sampling are predictive of the RT Candida incidence. RT Candida and candidemia incidences are correlated. RT Candida incidence can serve as a basis for benchmarking. Several relationships have been identified. The increased incidence among concurrent control groups of SDD studies cannot be appreciated in any single study examined in isolation.

Mechanical ventilation in patients in the intensive care unit of a general university hospital in southern Brazil: an epidemiological study

OBJECTIVES

To determine the characteristics, the frequency and the mortality rates of patients needing mechanical ventilation and to identify the risk factors associated with mortality in the intensive care unit (ICU) of a general university hospital in southern Brazil.

METHOD

Prospective cohort study in patients admitted to the ICU who needed mechanical ventilation for at least 24 hours between March 2004 and April 2007.

RESULTS

A total of 1,115 patients admitted to the ICU needed mechanical ventilation. The mortality rate was 51%. The mean age (± standard deviation) was 57±18 years, and the mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 22.6±8.3. The variables independently associated with mortality were (i) conditions present at the beginning of mechanical ventilation, age (hazard ratio: 1.01; p<0.001); the APACHE II score (hazard ratio: 1.01; p<0.005); acute lung injury/acute respiratory distress syndrome (hazard ratio: 1.38; p=0.009), sepsis (hazard ratio: 1.33; p=0.003), chronic obstructive pulmonary disease (hazard ratio: 0.58; p=0.042), and pneumonia (hazard ratio: 0.78; p=0.013) as causes of mechanical ventilation; and renal (hazard ratio: 1.29; p=0.011) and neurological (hazard ratio: 1.25; p=0.024) failure, and (ii) conditions occurring during the course of mechanical ventilation, acute lung injuri/acute respiratory distress syndrome (hazard ratio: 1.31; p<0.010); sepsis (hazard ratio: 1.53; p<0.001); and renal (hazard ratio: 1.75; p<0.001), cardiovascular (hazard ratio: 1.32; p≤0.009), and hepatic (hazard ratio: 1.67; p≤0.001) failure.

CONCLUSIONS

This large cohort study provides a comprehensive profile of mechanical ventilation patients in South America. The mortality rate of patients who required mechanical ventilation was higher, which may have been related to the severity of illness of the patients admitted to our ICU. Risk factors for hospital mortality included conditions present at the start of mechanical ventilation conditions that occurred during mechanical support.

Ventilator-associated pneumonia in ARDS patients: the impact of prone positioning. A secondary analysis of the PROSEVA trial

BACKGROUND

The goal of this study was to assess the impact of prone positioning on the incidence of ventilator-associated pneumonia (VAP) and the role of VAP in mortality in a recent multicenter trial performed on patients with severe ARDS.

METHODS

An ancillary study of a prospective multicenter randomized controlled trial on early prone positioning in patients with severe ARDS. In suspected cases of VAP the diagnosis was based on positive quantitative cultures of bronchoalveolar lavage fluid or tracheal aspirate at the 10(4) and 10(7) CFU/ml thresholds, respectively. The VAP cases were then subject to central, independent adjudication. The cumulative probabilities of VAP were estimated in each position group using the Aalen-Johansen estimator and compared using Gray's test. A univariate and a multivariate Cox model was performed to assess the impact of VAP, used as a time-dependent covariate for mortality hazard during the ICU stay.

RESULTS

In the supine and prone position groups, the incidence rate for VAP was 1.18 (0.86-1.60) and 1.54 (1.15-2.02) per 100 days of invasive mechanical ventilation (p = 0.10), respectively. The cumulative probability of VAP at 90 days was estimated at 46.5 % (27-66) in the prone group and at 33.5 % (23-44) in the supine group. The difference between the two cumulative probability curves was not statistically significant (p = 0.11). In the univariate Cox model, VAP was associated with an increase in the mortality rate during the ICU stay [HR 1.65 (1.05-2.61), p = 0.03]. HR increased to 2.2 (1.39-3.52) (p < 0.001) after adjustment for position group, age, SOFA score, McCabe score, and immunodeficiency.

CONCLUSIONS

In severe ARDS patients prone positioning did not reduce the incidence of VAP and VAP was associated with higher mortality.

Case fatality rate related to nosocomial and ventilator-associated pneumonia in an ICU: a single-centre retrospective cohort study

BACKGROUND

Nosocomial pneumonia (NP) and ventilator associated pneumonia (VAP) have been associated with financially significant economic burden and increased case fatality rate in adult intensive care units (ICUs). This study was designed to evaluate case fatality rate among patients with NP and VAP in a respiratory ICU.

METHODS

In 2008-2013, VAP and NP in the ICUs were included in this retrospective single-centre cohort study. Data on demographics, co-morbidities, severity of illness, mechanical ventilation, empirical treatment, length of hospital stay and laboratory findings were recorded in each group, as were case fatality rate during ICU admission and after discharge including short-term (28-day) and long-term (a year) case fatality rate.

RESULTS

A total of 108 patients with VAP (n = 64, median (IQR) age: 70 (61-75) years, 67.2% were men) or NP (n = 44, median (IQR) age: 68 (62-74) years, 68.2% were men) were found. Appropriate empirical antibiotic therapy was identified only in 45.2 and 42.9% of patients with VAP and NP, respectively. Overall case fatality rate in VAP and NP (81.3 vs 84.1), ICU case fatality rate (42.2 vs 45.5%), short-term case fatality rate (15.6 vs 27.3%) and long-term case fatality rate (23.4 vs 11.4%) were similar between VAP and NP groups along with occurrence 50% of case fatality rate cases in the first 2 months and 90% within the first year of discharge. Multivariate analysis showed that chronic obstructive pulmonary disease (COPD) (HR: 3.15, 95% CI: 1.06-9.38; p = 0.039) and presence of septic shock (HR: 3.83, 95% CI: 1.26-11.60; p = 0.018) were independently associated with lower survival.

CONCLUSION

In conclusion, our findings in a retrospective cohort of respiratory ICU patients with VAP or NP revealed high ICU, short- and long-term case fatality rates within 1 year of diagnosis, regardless of the diagnosis of NP after 48 h of initial admission or after induction of ventilator support. COPD and presence of septic shock are associated with high fatality rate and our findings speculate that as increasing compliance with infection control programs and close monitoring especially in 2 months of discharge might reduce high-case fatality rate in patients with VAP and NP.

Impact of tracheal cuff shape on microaspiration of gastric contents in intubated critically ill patients: study protocol for a randomized controlled trial

Background

Ventilator-associated pneumonia (VAP) is the most common infection in intubated critically ill patients. Microaspiration of the contaminated gastric and oropharyngeal secretions is the main mechanism involved in the pathophysiology of VAP. Tracheal cuff plays an important role in stopping the progression of contaminated secretions into the lower respiratory tract. Previous in vitro studies suggested that conical cuff shape might be helpful in improving tracheal sealing. However, clinical studies found conflicting results. The aim of this study is to determine the impact of conical tracheal cuff shape on the microaspiration of gastric contents in critically ill patients.

Methods/Design

This prospective cluster randomized controlled crossover open-label trial is currently being conducted in ten French intensive care units (ICUs). Patients are allocated to intubation with a polyvinyl chloride (PVC) standard (barrel)-shaped or a PVC conical-shaped tracheal tube. The primary objective is to determine the impact of the conical shaped tracheal cuff on abundant microaspiration of gastric contents. Secondary outcomes include the incidence of microaspiration of oropharyngeal secretions, tracheobronchial colonization, VAP and ventilator-associated events. Abundant microaspiration is defined as the presence of pepsin at significant level (>200 ng/ml) in at least 30 % of the tracheal aspirates. Pepsin and amylase are quantitatively measured in all tracheal aspirates during the 48 h following inclusion. Quantitative tracheal aspirate culture is performed at inclusion and twice weekly. We plan to recruit 312 patients in the participating ICUs.

Discussion

BEST Cuff is the first randomized controlled study evaluating the impact of PVC tracheal-cuff shape on gastric microaspirations in patients receiving invasive mechanical ventilation. Enrollment began in June 2014 and is expected to end in October 2015.

Trial registration

ClinicalTrials.gov Identifier: NCT01948635 (registered 31 August 2013).

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

OBJECTIVE:

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

METHODS:

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

RESULTS:

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

CONCLUSIONS:

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

Prevention of ventilator-associated pneumonia and ventilator-associated conditions: a randomized controlled trial with subglottic secretion suctioning

OBJECTIVES

Ventilator-associated pneumonia diagnosis remains a debatable topic. New definitions of ventilator-associated conditions involving worsening oxygenation have been recently proposed to make surveillance of events possibly linked to ventilator-associated pneumonia as objective as possible. The objective of the study was to confirm the effect of subglottic secretion suctioning on ventilator-associated pneumonia prevalence and to assess its concomitant impact on ventilator-associated conditions and antibiotic use.

DESIGN

Randomized controlled clinical trial conducted in five ICUs of the same hospital.

PATIENTS

Three hundred fifty-two adult patients intubated with a tracheal tube allowing subglottic secretion suctioning were randomly assigned to undergo suctioning (n = 170, group 1) or not (n = 182, group 2).

MAIN RESULTS

During ventilation, microbiologically confirmed ventilator-associated pneumonia occurred in 15 patients (8.8%) of group 1 and 32 patients (17.6%) of group 2 (p = 0.018). In terms of ventilatory days, ventilator-associated pneumonia rates were 9.6 of 1,000 ventilatory days and 19.8 of 1,000 ventilatory days, respectively (p = 0.0076). Ventilator-associated condition prevalence was 21.8% in group 1 and 22.5% in group 2 (p = 0.84). Among the 47 patients with ventilator-associated pneumonia, 25 (58.2%) experienced a ventilator-associated condition. Neither length of ICU stay nor mortality differed between groups; only ventilator-associated condition was associated with increased mortality. The total number of antibiotic days was 1,696 in group 1, representing 61.6% of the 2,754 ICU days, and 1,965 in group 2, representing 68.5% of the 2,868 ICU days (p < 0.0001).

CONCLUSIONS

Subglottic secretion suctioning resulted in a significant reduction of ventilator-associated pneumonia prevalence associated with a significant decrease in antibiotic use. By contrast, ventilator-associated condition occurrence did not differ between groups and appeared more related to other medical features than ventilator-associated pneumonia.

The effect of different oral hygiene treatments on the occurrence of ventilator associated pneumonia (VAP) in ventilated patients

BACKGROUND

We compared the incidence of ventilator associated pneumonia (VAP) among patients treated with comprehensive oral care to those treated with conventional methods of oral care.

METHODS

We conducted a prospective, controlled study in an intensive care unit of 90 ventilated patients. Patients in the study group received a comprehensive oral hygiene treatment regimen that involved tooth brushing, suctioning, sodium bicarbonate, rinsing with an antiseptic solution containing 1.5% hydrogen peroxide and a mouth moisturiser. Patients in the control group received a more conventional treatment that included cleaning with a sponge and atraumatic clamp, and rinsing with a 0.2% solution of chlorhexidine gluconate.

RESULTS

Among the 90 patients admitted to the ICU, 8.9% of the study group developed VAP compared with 33.3% of the control group (p< 0.004). The development of VAP per 1,000 ventilation days was 10.2 in the study group, and 29.5 in the control group (p< 0.06). The mean number of ventilation days and the mean number of hospitalisation days were also lower in the study group.

CONCLUSIONS

In patients who are ventilated, a comprehensive oral hygiene treatment regimen that includes tooth brushing, suctioning and rinsing with an antiseptic is more effective in preventing VAP than more conventional protocols.

Differences between novel and conventional surveillance paradigms of ventilator-associated pneumonia

OBJECTIVE

To investigate the concordance between novel and conventional surveillance paradigms for ventilator-associated pneumonia (VAP).

METHODS

This study was conducted at a regional teaching hospital in southern Taiwan with 5 acute intensive care units. To assess the validity of novel ventilator-associated event (VAE) surveillance, we retrospectively applied the VAE algorithm to analyze all VAP cases that were identified using conventional definitions between April 2010 and February 2014. Patient outcomes, including ventilator days, hospital stay lengths, and in-hospital mortality were recorded.

RESULTS

Among 165 episodes of conventional VAP, 55 (33.3%), 40 (24.2%), 20 (12.1%), and 2 (1.2%) episodes were classified as a ventilator-associated condition, an infection-related ventilator-associated complication, possible VAP, and probable VAP, respectively, according to the new VAE algorithm. Changes in positive end-expiratory pressure and inspired oxygen fraction levels during the development of VAP were significant higher among each VAE category than for conventional VAP (all P < .001). In-hospital mortality was significantly higher among patients with ventilator-associated condition than for patients with conventional VAP (P = .0185).

CONCLUSIONS

In our study population, novel VAE surveillance only detected one-third of conventional VAP cases. Thus, more studies are needed to further validate VAE surveillance compared with conventional VAP by using strong microbiologic criteria, particularly bronchoalveolar lavage with a protected specimen brush for diagnosing VAP.

Gastric residual volume in critically ill patients: a dead marker or still alive?

Early enteral nutrition (EN) is consistently recommended as first-line nutrition therapy in critically ill patients since it favorably alters outcome, providing both nutrition and nonnutrition benefits. However, critically ill patients receiving mechanical ventilation are at risk for regurgitation, pulmonary aspiration, and eventually ventilator-associated pneumonia (VAP). EN may increase these risks when gastrointestinal (GI) dysfunction is present. Gastric residual volume (GRV) is considered a surrogate parameter of GI dysfunction during the progression of enteral feeding in the early phase of critical illness and beyond. By monitoring GRV, clinicians may detect patients with delayed gastric emptying earlier and intervene with strategies that minimize or prevent VAP as one of the major risks of EN. The value of periodic GRV measurements with regard to risk reduction of VAP incidence has frequently been questioned in the past years. Increasing the GRV threshold before interrupting gastric feeding results in marginal increases in EN delivery. More recently, a large randomized clinical trial revealed that abandoning GRV monitoring did not negatively affect clinical outcomes (including VAP) in mechanically ventilated patients. The results have revived the discussion on the role of GRV monitoring in critically ill, mechanically ventilated patients receiving early EN. This review summarizes the most recent clinical evidence on the use of GRV monitoring in critically ill patients. Based on the clinical evidence, it discusses the pros and cons and further addresses whether GRV is a dead marker or still alive for the nutrition management of critically ill patients.

Impact of closed versus open tracheal suctioning systems for mechanically ventilated adults: a systematic review and meta-analysis

PURPOSE

Whether closed tracheal suctioning systems (CTSS) reduce the incidence of ventilator-associated pneumonia (VAP) compared with open tracheal suctioning systems (OTSS) is inconclusive. We conducted a systematic review and meta-analysis of randomized controlled trials that compared CTSS and OTSS.

METHODS

PubMed, the Cochrane Central Register of Controlled Trials, the Web of Science, Google Scholar, and a clinical trial registry from inception to October 2014 were searched without language restrictions. Randomized controlled trials of CTSS and OTSS that compared VAP in mechanically ventilated adult patients were included. The primary outcome was the incidence of VAP. Secondary outcomes were mortality and length of mechanical ventilation. Data were pooled using the random effects model.

RESULTS

Sixteen trials with 1,929 participants were included. Compared with OTSS, CTSS was associated with a reduced incidence of VAP (RR 0.69; 95 % CI 0.54-0.87; Q = 26.14; I (2) = 46.4 %). Compared with OTSS, CTSS was not associated with reduction of mortality (RR 0.96; 95 % CI 0.83-1.12; Q = 2.27; I (2) = 0.0 %) or reduced length of mechanical ventilation (WMD -0.45 days; 95 % CI -1.25 to 0.36; Q = 6.37; I (2) = 5.8 %). Trial sequential analysis suggested a lack of firm evidence for 20 % RR reduction in the incidence of VAP. The limitations of this review included underreporting and low quality of the included trials, as well as variations in study procedures and characteristics.

CONCLUSIONS

Based on current, albeit limited evidence, it is unlikely that CTSS is inferior to OTSS regarding VAP prevention; however, further trials at low risk of bias are needed to confirm or refute this finding.

A comparison of APACHE II and CPIS scores for the prediction of 30-day mortality in patients with ventilator-associated pneumonia

OBJECTIVE

The aim of this study was to compare the Acute Physiology and Chronic Health Evaluation II (APACHE II) score and the Clinical Pulmonary Infection Score (CPIS) for the prediction of 30-day mortality in patients with ventilator-associated pneumonia (VAP).

METHODS

A single-center, prospective cohort study design was employed between January 1, 2010 and January 1, 2014. APACHE II and CPIS scores were determined on the day of VAP diagnosis. Discrimination was tested using receiver-operating characteristic (ROC) curves and the areas under the curve (AUC). Calibration was tested using the Hosmer-Lemeshow statistic.

RESULTS

Of 135 patients with VAP, 39 died; the 30-day mortality was 28.9%. APACHE II and CPIS scores were significantly higher in non-survivors compared to survivors (23.1±4.8 vs. 16.7±4.6, p<0.001; 6.8±1.3 vs. 6.2±1.3, p=0.016). APACHE II had excellent discrimination for predicting 30-day mortality in patients with VAP, with AUC 0.808 (95% confidence interval (CI) 0.704-0.912, p<0.001). However, the CPIS score did not have discrimination power for predicting mortality, with AUC 0.612 (95% CI 0.485-0.739, p=0.083). The Hosmer-Lemeshow statistic showed good goodness-of-fit for observed 30-day mortality and APACHE II expected mortality (Chi-square=1.099, p=0.785). However, CPIS expected 30-day mortality did not fit the observed mortality (Chi-square=6.72, p=0.004).

CONCLUSIONS

These data suggest that APACHE II is useful for predicting 30-day mortality in patients with VAP, but that the CPIS does not have good discrimination and calibration for predicting mortality.

Alternative diagnosis in the putative ventilator-associated pneumonia patient not meeting lavage-based diagnostic criteria

BACKGROUND

The clinical picture of ventilator-associated pneumonia (VAP) can be mimicked by other infectious and non-infectious diseases. The aim of this study was to determine the alternative diagnoses and to develop a diagnostic flow chart for patients suspected of having VAP not meeting the diagnostic broncho-alveolar lavage (BAL) criteria.

METHODS

Adult intensive care patients with a clinical suspicion of VAP and negative BAL results were included. The clinical suspicion of VAP was based on the combination of clinical, radiological, and microbiological criteria. BAL was considered positive if cell differentiation revealed ≥ 2% cells with intracellular organisms and/or quantitative culture results of ≥ 10(4) cfu/ml. The most likely alternative diagnosis of fever and pulmonary densities was retrospectively determined by two authors independently.

RESULTS

In all, 110 of 207 patients with suspected VAP did not meet the diagnostic BAL criteria and required further diagnostic evaluation. In 67 patients an alternative diagnosis for fever could be found. In 51 patients an alternative diagnosis of both fever and pulmonary densities could be established. In almost 40% of patients no alternative diagnosis could be provided. Non-bacterial pneumonia was diagnosed in 10 patients with Herpes simplex virus 1 (HSV-1) as the most common pathogen. In eight patients non-infectious pneumonitis was diagnosed.

CONCLUSION

Due to the wide range of alternative diagnoses and applied tests the diagnostic work-up proved to be necessarily individualized and guided by repeated clinical assessment. The most frequently found alternative diagnoses were viral pneumonia and non-infectious pneumonitis.

Strategies to prevent ventilation-associated pneumonia: the effect of cuff pressure monitoring techniques and tracheal tube type on aspiration of subglottic secretions: an in-vitro study

BACKGROUND

Ventilation-associated pneumonia (VAP) is the commonest nosocomial infection in intensive care. Implementation of a VAP prevention care bundle is a proven method to reduce its incidence. The UK care bundle recommends maintenance of the tracheal tube cuff pressure at 20 to 30  cmH₂O with 4-hourly pressure checks and use of tracheal tubes with subglottic aspiration ports in patients admitted for more than 72  h.

OBJECTIVE

To evaluate the effects of tracheal tube type and cuff pressure monitoring technique on leakage of subglottic secretions past the tracheal tube cuff.

DESIGN

Bench-top study.

SETTING

Laboratory.

INTERVENTIONS

A model adult trachea with simulated subglottic secretions was intubated with a tracheal tube with the cuff inflated to 25  cmH₂O. Experiments were conducted using a Portex Profile Soft Seal tracheal tube with three cuff pressure monitoring strategies and using a Portex SACETT tracheal tube with intermittent cuff pressure checks.

OUTCOME MEASURES

Rate of simulated secretion leakage past the tracheal tube cuff.

RESULTS

Mean ± SD leakage of fluid past the Profile Soft Seal tracheal tube cuff was 2.25 ± 1.49  ml  min⁻¹ with no monitoring of cuff pressure, 2.98 ± 1.63  ml  min⁻¹ with intermittent cuff pressure monitoring and 3.83 ± 2.17  ml  min⁻¹ with continuous cuff pressure monitoring (P <0.001). Using a SACETT tracheal tube with a subglottic aspiration port and aspirating the simulated secretions prior to intermittent cuff pressure checks reduced the leakage rate to 0.50 ± 0.48  ml  min⁻¹ (P <0.001).

CONCLUSION

Subglottic secretions leaked past the tracheal tube cuff with all tube types and cuff pressure monitoring strategies in this model. Significantly higher rates were observed with continuous cuff pressure monitoring and significantly lower rates were observed when using a tracheal tube with a subglottic aspiration port. Further evaluation of medical device performance is needed in order to design more effective VAP prevention strategies.

Emergence of carbapenem-resistant Acinetobacter baumannii as the major cause of ventilator-associated pneumonia in intensive care unit patients at an infectious disease hospital in southern Vietnam

Ventilator-associated pneumonia (VAP) is a serious healthcare-associated infection that affects up to 30 % of intubated and mechanically ventilated patients in intensive care units (ICUs) worldwide. The bacterial aetiology and corresponding antimicrobial susceptibility of VAP is highly variable, and can differ between countries, national provinces and even between different wards in the same hospital. We aimed to understand and document changes in the causative agents of VAP and their antimicrobial susceptibility profiles retrospectively over an 11 year period in a major infectious disease hospital in southern Vietnam. Our analysis outlined a significant shift from Pseudomonas aeruginosa to Acinetobacter spp. as the most prevalent bacteria isolated from quantitative tracheal aspirates in patients with VAP in this setting. Antimicrobial resistance was common across all bacterial species and we found a marked proportional annual increase in carbapenem-resistant Acinetobacter spp. over a 3 year period from 2008 (annual trend; odds ratio 1.656, P = 0.010). We further investigated the possible emergence of a carbapenem-resistant Acinetobacter baumannii clone by multiple-locus variable number tandem repeat analysis, finding a blaOXA-23-positive strain that was associated with an upsurge in the isolation of this pathogen. We additionally identified a single blaNDM-1-positive A. baumannii isolate. This work highlights the emergence of a carbapenem-resistant clone of A. baumannii and a worrying trend of antimicrobial resistance in the ICU of the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam.

Factors related to compliance among critical care nurses with performing oral care protocols for mechanically ventilated patients in the intensive care unit

Oral care is an important component of the ventilator bundle; however, few studies have investigated the factors related to compliance with performing oral care among critical care nurses. In this observational study of 759 oral care opportunities performed by 133 critical care nurses, we found that the overall oral care compliance rate was 83.3%. Multivariate analysis revealed that nurses' age, academic degree, intensive care unit license, and location were independent predictors of performing oral care for patients in the intensive care unit.

Accuracy of alpha amylase in diagnosing microaspiration in intubated critically-ill patients

OBJECTIVES

Amylase concentration in respiratory secretions was reported to be a potentially useful marker for aspiration and pneumonia. The aim of this study was to determine accuracy of α-amylase in diagnosing microaspiration in critically ill patients.

METHODS

Retrospective analysis of prospectively collected data collected in a medical ICU. All patients requiring mechanical ventilation for at least 48 h, and included in a previous randomized controlled trial were eligible for this study, provided that at least one tracheal aspirate was available for α-amylase measurement. As part of the initial trial, pepsin was quantitatively measured in all tracheal aspirates during a 48-h period. All tracheal aspirates were frozen, allowing subsequent measurement of α-amylase for the purpose of the current study. Microaspiration was defined as the presence of at least one positive tracheal aspirate for pepsin (>200 ng.mL-1). Abundant microaspiration was defined as the presence of pepsin at significant level in >74% of tracheal aspirates.

RESULTS

Amylase was measured in 1055 tracheal aspirates, collected from 109 patients. Using mean α-amylase level per patient, accuracy of α-amylase in diagnosing microaspiration was moderate (area under the receiver operator curve 0.72±0.05 [95%CI 0.61-0.83], for an α-amylase value of 1685 UI.L-1). However, when α-amylase levels, coming from all samples, were taken into account, area under the receiver operator curve was 0.56±0.05 [0.53-0.60]. Mean α-amylase level, and percentage of tracheal aspirates positive for α-amylase were significantly higher in patients with microaspiration, and in patients with abundant microaspiration compared with those with no microaspiration; and similar in patients with microaspiration compared with those with abundant microaspiration. α-amylase and pepsin were significantly correlated (r2 = 0.305, p = 0.001).

CONCLUSION

Accuracy of mean α-amylase in diagnosing microaspiration is moderate. Further, when all α-amylase levels were taken into account, α-amylase was inaccurate in diagnosing microaspiration, compared with pepsin.

Losartan attenuates microvascular permeability in mechanical ventilator-induced lung injury in diabetic mice

Mechanical ventilation can cause direct injury to the lungs, a type of injury known as ventilator-induced lung injury (VILI). VILI is associated with up-regulates angiotensinogen and AT1 receptor expression of in the lung. This work explored effects of losartan on VILI in diabetic mice. Ninty-six C57Bl/6 mice were randomly divided into six groups, control group (C group), diabetes group (D group), diabetes mechanical ventilation group (DV group), losartan control group (L + C group), losartan treatment group in diabetic mice (L + D group) and losartan treatment group in mechanical ventilation diabetic mice (L + DV group). Lung W/D, myeloperoxidase (MPO) activity, microvascular permeability, blood-gas analysis, Ang II concentrations and AT-1R protein expression were measured. Compared with D group, DV group increased Ang II concentrations, AT-1R protein expression, W/D ratio, MPO activity, and microvascular permeability. PaO2 were significantly lower in the DV group than D group or control group. Compared with DV group, L + DV group attenuates ventilator-induced lung injury in diabetic mice and prevented the increase Ang II concentrations, AT-1R protein expression and microvascular permeability caused by ventilation in diabetic mice. This study provides in vivo evidence that losartan attenuates microvascular permeability via down-regulates Ang II and AT-1R expression in mechanical ventilator-induced lung injury in diabetic mice.

Underlying illness severity and outcome of nosocomial pneumonia: prospective cohort study in intensive care unit

BACKGROUND

Previous studies have suggested that the final outcome of a patient with nosocomial pneumonia (NP) may depend on the patient's illness severity upon admission to the intensive care unit (ICU).

AIM

To investigate the relationship between developing NP during hospitalization in an adult ICU and the risk of death with special focus on illness severity at admission in the unit.

METHODS

A prospective cohort study was performed among all patients admitted for at least 24h to the ICU of a university reference hospital in Spain from 2006 to 2009. A stratified univariate study was performed according to the patients' illness severity at admission, estimated using the Acute Physiology And Chronic Health Evaluation (APACHE) II index. To determine whether the NP was independently associated with increased mortality in ICU, a multivariate logistic regression analysis was carried out, adjusting for potential confounders.

RESULTS

In all, 4427 patients were studied, of whom 233 acquired NP while admitted. Patients who developed NP had a 2.6 higher risk (95% confidence interval: 2.1-3.0) of dying compared with those who did not develop NP. When stratified by the APACHE II index, the significant association remained at each stratum, although the strength of the association decreased as the value of the index increased. In the multivariate analysis, NP was independently associated with death in the ICU. The interaction between NP and the APACHE II index, with a negative coefficient, was also significant.

CONCLUSIONS

Developing NP while admitted to the ICU was independently associated with increased mortality. However, the strength of the association decreased as the severity of patient illness upon admission to the ICU increased, not influencing death of patients with severe APACHE II values.

The perfidious effect of topical placebo: calibration of Staphylococcus aureus ventilator-associated pneumonia incidence within selective digestive decontamination studies versus the broader evidence base

Among various methods for preventing ventilator-associated pneumonia (VAP), the evidence base for selective digestive decontamination (SDD) appears most compelling. However, the extent of Staphylococcus aureus emergence with SDD use remains uncertain. Groups from 37 observational studies and component (control and intervention) groups from 58 studies of SDD and other methods of VAP prevention were sourced exclusively from 10 systematic reviews. S. aureus as a proportion of VAP isolates (S. aureus isolate proportion [S. aureus IP]) among component groups was calibrated versus that among observational groups (the benchmark). The influence of topical placebo used for blinding purposes and other group-level factors was estimated using generalized estimating equation methods (GEE). The mean S. aureus IP is 22% (95% confidence interval [CI], 19 to 25) for 37 observational groups versus 32% (24 to 41) and 20% (15 to 25) for 22 control groups from the SDD evidence base which did versus did not receive topical placebo, respectively. In GEE models including all 148 observational and component groups, membership of a control (P = 0.03) or intervention (P < 0.001) group of an SDD study that used topical placebo was associated with higher S. aureus IP, whereas, in contrast, membership of these groups was without effect on Pseudomonas aeruginosa. Topical placebo is implicated as a vehicle for selective cross-infection with S. aureus within the specific context of the SDD evidence base. This effect of topical placebo is perfidious; it could contribute to the higher VAP incidence and inflate the apparent "effectiveness" of SDD. The SDD evidence base requires reappraisal.

Life expectancy of brain impaired, chronically ventilated children

We present a 5-year survival profile of 42 children and adolescents between 1 to 21 years of age in an immobile minimally conscious state, chronically dependent on supportive ventilation. Data were collected from a 22-bed pediatric unit dedicated to this unique population, within a 350-bed geriatric hospital, between May 2006 and May 2011. The practice of ventilating children even in minimally conscious state stems from the unique cultural, religious, and ethnic background of the population in Israel. The 5-year survival probability was 48% (52% probability of death within 5 years, 26.5% within 2 years). No significant difference was found in the survival profile of patients admitted following hypoxic accidents (20 children) and those admitted with other problems such as genetic/metabolic diseases or brain anomalies (22). The mortality rate of male patients was higher than that of female patients, but the difference was not statistically significant. No difference in 5-year mortality rates was found between children of different ethnic backgrounds.

Asking the right questions: the relationship between incident ventilator-associated pneumonia and mortality

Whether ventilator-associated pneumonia is a manifestation of severity of illness or an independent cause of mortality in ventilator-dependent patients is not known. In this complex area, which cannot be readily subjected to randomized controlled trials, studies should focus on the underlying questions of relevance, how to improve care of ventilated patients.