Epidemiology of healthcare-associated Pseudomonas aeruginosa in intensive care units: are sink drains to blame?

BACKGROUND

Pseudomonas aeruginosa (PA) is a common cause of healthcare-associated infection (PA-HAI) in the intensive care unit (ICU).

AIM

To describe the epidemiology of PA-HAI in ICUs in Ontario, Canada, and to identify episodes of sink-to-patient PA transmission.

METHODS

This was a prospective cohort study of patients in six ICUs from 2018 to 2019, with retrieval of PA clinical isolates, and PA-screening of antimicrobial-resistant organism surveillance rectal swabs, and of sink drain, air, and faucet samples. All PA isolates underwent whole-genome sequencing. PA-HAI was defined using US National Healthcare Safety Network criteria. ICU-acquired PA was defined as PA isolated from specimens obtained ≥48 h after ICU admission in those with prior negative rectal swabs. Sink-to-patient PA transmission was defined as ICU-acquired PA with close genomic relationship to isolate(s) previously recovered from sinks in a room/bedspace occupied 3-14 days prior to collection date of the relevant patient specimen.

FINDINGS

Over ten months, 72 PA-HAIs occurred among 60/4263 admissions. The rate of PA-HAI was 2.40 per 1000 patient-ICU-days; higher in patients who were PA-colonized on admission. PA-HAI was associated with longer stay (median: 26 vs 3 days uninfected; P < 0.001) and contributed to death in 22/60 cases (36.7%). Fifty-eight admissions with ICU-acquired PA were identified, contributing 35/72 (48.6%) PA-HAIs. Four patients with five PA-HAIs (6.9%) had closely related isolates previously recovered from their room/bedspace sinks.

CONCLUSION

Nearly half of PA causing HAI appeared to be acquired in ICUs, and 7% of PA-HAIs were associated with sink-to-patient transmission. Sinks may be an under-recognized reservoir for HAIs.

Performance of ICD-10-AM codes for quality improvement monitoring of hospital-acquired pneumonia in a haematology-oncology casemix in Victoria, Australia

BACKGROUND

The Australian hospital-acquired complication (HAC) policy was introduced to facilitate negative funding adjustments in Australian hospitals using ICD-10-AM codes.

OBJECTIVE

The aim of this study was to determine the positive predictive value (PPV) of the ICD-10-AM codes in the HAC framework to detect hospital-acquired pneumonia in patients with cancer and to describe any change in PPV before and after implementation of an electronic medical record (EMR) at our centre.

METHOD

A retrospective case review of all coded pneumonia episodes at the Peter MacCallum Cancer Centre in Melbourne, Australia spanning two time periods (01 July 2015 to 30 June 2017 [pre-EMR period] and 01 September 2020 to 28 February 2021 [EMR period]) was performed to determine the proportion of events satisfying standardised surveillance definitions.

RESULTS

HAC-coded pneumonia occurred in 3.66% (n = 151) of 41,260 separations during the study period. Of the 151 coded pneumonia separations, 27 satisfied consensus surveillance criteria, corresponding to an overall PPV of 0.18 (95% CI: 0.12, 0.25). The PPV was approximately three times higher following EMR implementation (0.34 [95% CI: 0.19, 0.53] versus 0.13 [95% CI: 0.08, 0.21]; p = .013).

CONCLUSION

The current HAC definition is a poor-to-moderate classifier for hospital-acquired pneumonia in patients with cancer and, therefore, may not accurately reflect hospital-level quality improvement. Implementation of an EMR did enhance case detection, and future refinements to administratively coded data in support of robust monitoring frameworks should focus on EMR systems.

IMPLICATIONS

Although ICD-10-AM data are readily available in Australian healthcare settings, these data are not sufficient for monitoring and reporting of hospital-acquired pneumonia in haematology-oncology patients.

Application of ventilator-associated events (VAE) in ventilator-associated pneumonia (VAP) notified in Brazil (IMPACTO MR-PAV): a protocol for a cohort study

INTRODUCTION

Certain criteria for ventilator-associated events (VAE) definition might influence the type of an event, its detection rate and consequently the resource expenditure in intensive care unit. The Impact of Infections by Antimicrobial-Resistant Microorganisms - Ventilator-Associated Pneumonia (IMPACTO MR-PAV) aims to evaluate the incidence and diagnostic accuracy of ventilator-associated pneumonia (VAP) using the current criteria for VAP surveillance in Brazil versus the VAE criteria defined by the US National Healthcare Safety Network-Center for Diseases Control and Prevention (CDC) criteria.

METHODS AND ANALYSIS

The study will be conducted in around 15 centres across Brazil from October 2022 to December 2023. Trained healthcare professionals will collect data and compare the incidence of VAP using both the current criteria for VAP surveillance in Brazil and the VAE criteria defined by the CDC. The accuracy of the two criteria for identifying VAP will also be analysed. It will also characterise other events associated with mechanical ventilation (ventilator-associated condition, infection-related ventilator-associated complication) and adjudicate VAP reported to the Brazilian Health Regulatory Agency (ANVISA) using current epidemiological diagnostic criteria.

ETHICS AND DISSEMINATION

This study was approved by the Institutional Review Board under the number 52354721.0.1001.0070. The study's primary outcome measure will be the incidence of VAP using the two different surveillance criteria, and the secondary outcome measures will be the accuracy of the two criteria for identifying VAP and the adjudication of VAP reported to ANVISA. The results will contribute to the improvement of VAP surveillance in Brazil and may have implications for other countries that use similar criteria.

TRIAL REGISTRATION NUMBER

NCT05589727; Clinicaltrials.gov.

Increased rates of secondary bacterial infections, including Enterococcus bacteremia, in patients hospitalized with coronavirus disease 2019 (COVID-19)

OBJECTIVE

We compared the rates of hospital-onset secondary bacterial infections in patients with coronavirus disease 2019 (COVID-19) with rates in patients with influenza and controls, and we investigated reports of increased incidence of Enterococcus infections in patients with COVID-19.

DESIGN

Retrospective cohort study.

SETTING

An academic quaternary-care hospital in San Francisco, California.

PATIENTS

Patients admitted between October 1, 2019, and October 1, 2020, with a positive SARS-CoV-2 PCR (N = 314) or influenza PCR (N = 82) within 2 weeks of admission were compared with inpatients without positive SARS-CoV-2 or influenza tests during the study period (N = 14,332).

METHODS

National Healthcare Safety Network definitions were used to identify infection-related ventilator-associated complications (IVACs), probable ventilator-associated pneumonia (PVAP), bloodstream infections (BSIs), and catheter-associated urinary tract infections (CAUTIs). A multiple logistic regression model was used to control for likely confounders.

RESULTS

COVID-19 patients had significantly higher rates of IVAC and PVAP compared to controls, with adjusted odds ratios of 4.7 (95% confidence interval [CI], 1.7-13.9) and 10.4 (95 % CI, 2.1-52.1), respectively. COVID-19 patients had higher incidence of BSI due to Enterococcus but not BSI generally, and whole-genome sequencing of Enterococcus isolates demonstrated that nosocomial transmission did not explain the increased rate. Subanalyses of patients admitted to the intensive care unit and patients who required mechanical ventilation revealed similar findings.

CONCLUSIONS

COVID-19 is associated with an increased risk of IVAC, PVAP, and Enterococcus BSI compared with hospitalized controls, which is not fully explained by factors such as immunosuppressive treatments and duration of mechanical ventilation. The mechanism underlying increased rates of Enterococcus BSI in COVID-19 patients requires further investigation.

Ventilator-associated events versus ventilator-associated respiratory infections-moving into a new paradigm or merging both concepts, instead?

Despite ventilator-associated respiratory infections (VARI) are reported as the most common and fatal complications related to mechanical ventilation (MV), they are not the unique occurrences. The new classification of ventilator-associated events (VAE) proposed by the centers for disease control and prevention (CDC) enhance the spectra of complications due to MV including both infection-related and non-infectious events. Both VAEs and VARIs are associated with prolonged duration of MV, longer stay in hospital and in the intensive care unit (ICU) and more antibiotic consumption, nonetheless patients with VAEs have worst outcomes. The VARI and VAE algorithms are focused on different targets and the correlation between both classifications is shown to be poor. The diagnostic criteria of the traditional classification have limited accuracy and the non-infectious complications may be misinterpreted as VARI. While the VAE surveillance enhances the spectra of MV complications but excludes less severe VARIs. Noninfective events explain up to 30% of VAEs, the main causes being atelectasis, acute respiratory distress syndrome, pulmonary edema and pulmonary embolism. The bundles assessing VAE are associated with less incidence of VAP and improved outcomes but they fail to reduce the rates of VAE. Automated VAE surveillance is efficient and useful as a quality indicator in the ICU while the differences in the interpretation of VARI criteria limit its role in the design of global protocols and preventive strategies. We suggest that a more comprehensive strategy should combine both algorithms with emphasis on clinical outcomes.

Controversies and advances in the management of ventilator associated pneumonia

INTRODUCTION

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

Ventilator-Associated Pneumonia: The Role of Emerging Diagnostic Technologies

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

Evaluation of Quality Indicators in an Indian Intensive Care Unit Using "CHITRA" Database

Background:

Quality indicators (QIs) are essential for maintaining quality of care in the critically ill. The Indian Society of Critical Care Medicine proposed benchmarks and enabled Indian Intensive Care Units (ICUs) to capture data in an electronic database: Customized Health in Intensive Care Trainable Research and Analysis (CHITRA) tool. The purpose of this study is to report QIs in an Indian ICU using this database.

Materials and Methods:

Data from patients admitted to ICU between October 2015 and January 2017 were entered into CHITRA. The following QIs were analyzed: standardized mortality ratio (SMR), length of ICU stay (LOS-ICU), pressure ulcer (PU) rate, patient fall rate (FR), ICU readmission rate, reintubation rate, ventilator-associated condition (VAC), central line-associated bloodstream infection (CLABSI), catheter-associated urinary tract infection (CAUTI), and iatrogenic pneumothorax rate.

Results:

A total of 2642 patient's information was suitable for analysis. Median age of ICU admission was 53 years (interquartile range [IQR]: 36–65), with a mean APACHE score of 18 (SD 7.7). Median LOS-ICU was 3 days (IQR 2–6) and SMR was 1.1 (95% confidence interval 1.05–1.38). Pneumothorax rate, PU rate, and FR were 2.6, 4.1, and 0.3 per 1000 respectively, whereas readmission rate was 0.7% and reintubation rate was 3.5%. VAC, CLABSI, and CAUTI were 8.5, 23, 3.1 per 1000 ventilator and catheter days, respectively.

Conclusion:

This study has successfully evaluated a range of QIs in a mixed ICU of a tertiary hospital utilizing CHITRA database.

Update on ventilator-associated pneumonia

PURPOSE OF REVIEW

To highlight the importance of escalating pathogen resistance in ventilator-associated pneumonia (VAP) along with diagnostic and treatment implications.

RECENT FINDINGS

In a period of rising bacterial resistance, VAP remains an important infection occurring in critically ill patients. Risk factors for multidrug-resistant pathogens depend on both local epidemiology and host factors. New diagnostic techniques and antimicrobials can help with rapid bacterial identification and timely and appropriate treatment while avoiding emergence of bacterial resistance.

SUMMARY

Clinicians should be aware of risk factors for multidrug-resistant pathogens causing VAP and also of particularities of diagnosis and treatment of this important clinical entity.

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

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

Clinical predictors and microbiology of ventilator-associated pneumonia in the intensive care unit: a retrospective analysis in six Italian hospitals

The purpose of this study was to assess the main clinical predictors and microbiological features of ventilator-associated pneumonia (VAP) in the Intensive Care Unit (ICU) environment. This work is a retrospective analysis over one year from September 2010 to September 2011. Patients' risk factors, causes of admission, comorbidities and respiratory specimens collected in six Italian ICUs were reviewed. Incidence and case fatality rate of VAP were evaluated. After stratification for VAP development, univariate and multivariate analyses were performed to assess the impact of patients' conditions on the onset of this infection. A total of 1,647 ICU patients (pts) were considered. Overall, 115 patients (6.9 %) experienced at least one episode of VAP. The incidence rate for VAP was 5.82/1,000 pts-days, with a case fatality rate of 44.3 %. Multivariate analysis showed that admission for neurological disorders (aIRR 4.12, CI 1.24-13.68, p = 0.02) and emergency referral to ICU from other hospitals (aIRR 2.11, CI 1.03-4.31, p = 0.04) were associated with higher risk of VAP, whereas a tendency to a higher risk of infection was detected for admission due to respiratory disease, cardiac disease, trauma and for having obesity or renal failure. A total of 372 microbiological isolates from respiratory specimens were collected in VAP patients. The most common species were Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa, showing high resistance rates to carbapenems. Neurological disorders and emergency referral at the admission into the ICU are significantly associated with the onset of VAP. A high incidence of multi-drug resistant Gram- species was detected in the respiratory specimens.

Composition and dynamics of the respiratory tract microbiome in intubated patients

BACKGROUND

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

RESULTS

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

CONCLUSIONS

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

The Centers for Disease Control and Prevention's New Definitions for Complications of Mechanical Ventilation Shift the Focus of Quality Surveillance and Predict Clinical Outcomes in a PICU

OBJECTIVES

The Centers for Disease Control and Prevention shifted the focus of surveillance paradigm for adult patients receiving mechanical ventilation, moving from the current standard of ventilator-associated pneumonia to broader complications. The surveillance definitions were designed to enable objective measures and efficient processes, so as to facilitate quality improvement initiatives and enhance standardized benchmark comparisons. We evaluated the surveillance definitions in term of their ability to predict clinical outcomes and ease of surveillance in a PICU.

DESIGN

Retrospective cohort study.

SETTING

A PICU at a university-affiliated children's hospital.

PATIENTS

Eight hundred thirty-six patients receiving mechanical ventilation over 1-year period.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We applied the definition for ventilator-associated condition (i.e., a sustained increase in ventilator setting after a period of stable or decreasing support) to our database. Of total 606 patients, 14.5% had ventilator-associated condition (20.9/1,000 ventilator days) and 8.1% had an infection-related ventilator-associated condition (12.9/1,000 ventilator days). The patients with infection-related ventilator-associated condition were classified into probable pneumonia (55%), possible pneumonia (28.6%), and undetermined infection (16.3%). A large portion of patients with ventilator-associated condition (44%) had other noninfectious etiologies (e.g., atelectasis, pulmonary edema, and shock). Patients who developed ventilator-associated condition had significantly longer ventilatory, ICU, and hospital days compared with those who did not. The ventilator-associated condition group had increased hospital mortality compared with the non-ventilator-associated condition group (19.3% vs 6.9%; p=0.0007). Multivariate regression analysis identified ventilator-associated condition as one of the predictors of hospital mortality with an adjusted odds ratio of 2.14 (95% CI, 1.03-4.42). Risk factors for developing a ventilator-associated condition included immunocompromised status (odds ratio, 2.90; 95% CI, 1.57-5.33), tracheostomy dependence (odds ratio, 2.78; 95% CI, 1.40-5.51), and chronic respiratory disease (odds ratio, 1.85; 95% CI, 1.03-3.3).

CONCLUSIONS

The definitions for the various ventilator-associated conditions are good predictors of outcomes in children and adults and are amenable to automated surveillance. Based on the study findings, we suggest consideration for shifting the focus of surveillance for ventilator-associated events from only pneumonia to a broader range of complications.

Prone position for acute respiratory failure in adults

BACKGROUND

Acute hypoxaemia de novo or on a background of chronic hypoxaemia is a common reason for admission to intensive care and for provision of mechanical ventilation. Various refinements of mechanical ventilation or adjuncts are employed to improve patient outcomes. Mortality from acute respiratory distress syndrome, one of the main contributors to the need for mechanical ventilation for hypoxaemia, remains approximately 40%. Ventilation in the prone position may improve lung mechanics and gas exchange and could improve outcomes.

OBJECTIVES

The objectives of this review are (1) to ascertain whether prone ventilation offers a mortality advantage when compared with traditional supine or semi recumbent ventilation in patients with severe acute respiratory failure requiring conventional invasive artificial ventilation, and (2) to supplement previous systematic reviews on prone ventilation for hypoxaemic respiratory failure in an adult population.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 1), Ovid MEDLINE (1950 to 31 January 2014), EMBASE (1980 to 31 January 2014), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 31 January 2014) and Latin American Caribbean Health Sciences Literature (LILACS) (1992 to 31 January 2014) in Ovid MEDLINE for eligible randomized controlled trials. We also searched for studies by handsearching reference lists of relevant articles, by contacting colleagues and by handsearching published proceedings of relevant journals. We applied no language constraints, and we reran the searches in CENTRAL, MEDLINE, EMBASE, CINAHL and LILACS in June 2015. We added five new studies of potential interest to the list of "Studies awaiting classification" and will incorporate them into formal review findings during the review update.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that examined the effects of prone position versus supine/semi recumbent position during conventional mechanical ventilation in adult participants with acute hypoxaemia.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed all trials identified by the search and assessed them for suitability, methods and quality. Two review authors extracted data, and three review authors reviewed the data extracted. We analysed data using Review Manager software and pooled included studies to determine the risk ratio (RR) for mortality and the risk ratio or mean difference (MD) for secondary outcomes; we also performed subgroup analyses and sensitivity analyses.

MAIN RESULTS

We identified nine relevant RCTs, which enrolled a total of 2165 participants (10 publications). All recruited participants suffered from disorders of lung function causing moderate to severe hypoxaemia and requiring mechanical ventilation, so they were fairly comparable, given the heterogeneity of specific disease diagnoses in intensive care. Risk of bias, although acceptable in the view of the review authors, was inevitable: Blinding of participants and carers to treatment allocation was not possible (face-up vs face-down).Primary analyses of short- and longer-term mortality pooled from six trials demonstrated an RR of 0.84 to 0.86 in favour of the prone position (PP), but findings were not statistically significant: In the short term, mortality for those ventilated prone was 33.4% (363/1086) and supine 38.3% (395/1031). This resulted in an RR of 0.84 (95% confidence interval (CI) 0.69 to 1.02) marginally in favour of PP. For longer-term mortality, results showed 41.7% (462/1107) for prone and 47.1% (490/1041) for supine positions, with an RR of 0.86 (95% CI 0.72 to 1.03). The quality of the evidence for both outcomes was rated as low as a result of important potential bias and serious inconsistency.Subgroup analyses for mortality identified three groups consistently favouring PP: those recruited within 48 hours of meeting entry criteria (five trials; 1024 participants showed an RR of 0.75 (95% CI 0.59 to 94)); those treated in the PP for 16 or more hours per day (five trials; 1005 participants showed an RR of 0.77 (95% CI 0.61 to 0.99)); and participants with more severe hypoxaemia at trial entry (six trials; 1108 participants showed an RR of 0.77 (95% CI 0.65 to 0.92)). The quality of the evidence for these outcomes was rated as moderate as a result of potentially important bias.Prone positioning appeared to influence adverse effects: Pressure sores (three trials; 366 participants) with an RR of 1.37 (95% CI 1.05 to 1.79) and tracheal tube obstruction with an RR of 1.78 (95% CI 1.22 to 2.60) were increased with prone ventilation. Reporting of arrhythmias was reduced with PP, with an RR of 0.64 (95% CI 0.47 to 0.87).

AUTHORS' CONCLUSIONS

We found no convincing evidence of benefit nor harm from universal application of PP in adults with hypoxaemia mechanically ventilated in intensive care units (ICUs). Three subgroups (early implementation of PP, prolonged adoption of PP and severe hypoxaemia at study entry) suggested that prone positioning may confer a statistically significant mortality advantage. Additional adequately powered studies would be required to confirm or refute these possibilities of subgroup benefit but are unlikely, given results of the most recent study and recommendations derived from several published subgroup analyses. Meta-analysis of individual patient data could be useful for further data exploration in this regard. Complications such as tracheal obstruction are increased with use of prone ventilation. Long-term mortality data (12 months and beyond), as well as functional, neuro-psychological and quality of life data, are required if future studies are to better inform the role of PP in the management of hypoxaemic respiratory failure in the ICU.

A Case-Control Study on the Impact of Ventilator-Associated Tracheobronchitis in the PICU

OBJECTIVES

Hospital-acquired infections increase morbidity, mortality, and charges in the PICU. We implemented a quality improvement bundle directed at ventilator-associated pneumonia in our PICU in 2005. We observed an increase in ventilator-associated tracheobronchitis coincident with the near-elimination of ventilator-associated pneumonia. The impact of ventilator-associated tracheobronchitis on critically ill children has not been previously described. Accordingly, we hypothesized that ventilator-associated tracheobronchitisis associated with increased length of stay, mortality, and hospital charge.

DESIGN

Retrospective case-control study.

PATIENTS

Critically ill children admitted to a quaternary PICU at a free-standing academic children's hospital in the United States.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We conducted a retrospective case control study, with institutional review board approval, of 77 consecutive cases of ventilator-associated tracheobronchitis admitted to our PICU from 2004-2010. We matched each case with a control based on the following criteria (in rank order): age range (< 30 d, 30 d to 24 mo, 24 mo to 12 yr, > 12 yr), admission Pediatric Risk of Mortality III score ± 10, number of ventilator days of control group (> 75% of days until development of ventilator-associated tracheobronchitis), primary diagnosis, underlying organ system dysfunction, surgical procedure, and gender. The primary outcome measured was PICU length of stay. Secondary outcomes included ventilator days, hospital length of stay, mortality, and PICU and hospital charges. Data was analyzed using chi square analysis and p less than 0.05 was considered significant. We successfully matched 45 of 77 ventilator-associated tracheobronchitis patients with controls. There were no significant differences in age, gender, diagnosis, or Pediatric Risk of Mortality III score between groups. Ventilator-associated tracheobronchitis patients had a longer PICU length of stay (median, 21.5 d, interquartile range, 24 d) compared to controls (median, 18 d; interquartile range, 17 d), although not statistically significant (p = 0.13). Ventilator days were also longer in the ventilator-associated tracheobronchitis patients (median, 17 d; IQR, 22 d) versus control (median, 10.5 d; interquartile range, 13 d) (p = 0.01). There was no significant difference in total hospital length of stay (54 d vs 36 d; p = 0.69). PICU mortality was higher in the ventilator-associated tracheobronchitis group (15% vs 5%; p = 0.14), although not statistically significant. There was an increase in both median PICU charges ($197,393 vs $172,344; p < 0.05) and hospital charges ($421,576 vs $350,649; p < 0.05) for ventilator-associated tracheobronchitis patients compared with controls.

CONCLUSIONS

Ventilator-associated tracheobronchitis is a clinically significant hospital-acquired infection in the PICU and is associated with longer duration of mechanical ventilation and healthcare costs, possibly through causing a longer PICU length of stay. Quality improvement efforts should be directed at reducing the incidence of ventilator-associated tracheobronchitis in the PICU.

Bacteremia Antibiotic Length Actually Needed for Clinical Effectiveness (BALANCE): study protocol for a pilot randomized controlled trial

Background

Bacteremia is a leading cause of mortality and morbidity in critically ill adults. No previous randomized controlled trials have directly compared shorter versus longer durations of antimicrobial treatment in these patients.

Methods/Design

This is a multicenter pilot randomized controlled trial in critically ill patients with bacteremia. Eligible patients will be adults with a positive blood culture with pathogenic bacteria identified while in the intensive care unit. Eligible, consented patients will be randomized to either 7 days or 14 days of adequate antimicrobial treatment for the causative pathogen(s) detected on blood cultures. The diversity of pathogens and treatment regimens precludes blinding of patient and clinicians, but allocation concealment will be extended to day 7 and outcome adjudicators will be blinded. The primary outcome for the main trial will be 90-day mortality. The primary outcome for the pilot trial is feasibility defined by (i) rate of recruitment exceeding 1 patient per site per month and (ii) adherence to treatment duration protocol ≥ 90%. Secondary outcomes include intensive care unit, hospital and 90-day mortality rates, relapse rates of bacteremia, antibiotic-related side effects and adverse events, rates of Clostridium difficile infection, rates of secondary infection or colonization with antimicrobial resistant organisms, ICU and hospital lengths of stay, mechanical ventilation and vasopressor duration in intensive care unit, and procalcitonin levels on the day of randomization, and day 7, 10 and 14 after the index blood culture.

Discussion

The BALANCE pilot trial will inform the design and execution of the subsequent BALANCE main trial, which will evaluate shorter versus longer duration treatment for bacteremia in critically ill patients, and thereby provide an evidence basis for treatment duration decisions for these infections.

Trial registration

The Pilot Trial was registered on 26 September 2014. Trial registration number: NCT02261506.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-0688-z) contains supplementary material, which is available to authorized users.

Automated surveillance for ventilator-associated events

BACKGROUND

The US Centers for Disease Control and Prevention has implemented a new, multitiered definition for ventilator-associated events (VAEs) to replace their former definition of ventilator-associated pneumonia (VAP). We hypothesized that the new definition could be implemented in an automated, efficient, and reliable manner using the electronic health record and that the new definition would identify different patients than those identified under the previous definition.

METHODS

We conducted a retrospective cohort analysis using an automated algorithm to analyze all patients admitted to the ICU at a single urban, tertiary-care hospital from 2008 to 2013.

RESULTS

We identified 26,466 consecutive admissions to the ICU, 10,998 (42%) of whom were mechanically ventilated and 675 (3%) of whom were identified as having any VAE. Any VAE was associated with an adjusted increased risk of death (OR, 1.91; 95% CI, 1.53-2.37; P < .0001). The automated algorithm was reliable (sensitivity of 93.5%, 95% CI, 77.2%-98.8%; specificity of 100%, 95% CI, 98.8%-100% vs a human abstractor). Comparison of patients with a VAE and with the former VAP definition yielded little agreement (κ = 0.06).

CONCLUSIONS

A fully automated method of identifying VAEs is efficient and reliable within a single institution. Although VAEs are strongly associated with worse patient outcomes, additional research is required to evaluate whether and which interventions can successfully prevent VAEs.

Review on the Antimicrobial Resistance of Pathogens from Tracheal and Endotracheal Aspirates of Patients with Clinical Manifestations of Pneumonia in Bacolod City in 2013

Microbiological content specifically bacterial and fungal etiologies from tracheal aspirates in a tertiary hospital in Bacolod City was reviewed for baseline information. A total of 130 tracheal aspirates were subjected for culture to isolate and identify the pathogen and determine their susceptibilities to various antibiotics. Productions of certain enzymes responsible for antibiotic resistance like ESBL (Extended Spectrum Beta-Lactamase), metallo-β-lactamase, and carbapenemase were also studied. Out of 130 specimens, 69.23% were found to be positive for the presence of microorganisms. Most infections were from male patients aging 60 years and above, confined at the Intensive Care Units (ICU). Pseudomonas aeruginosa and Klebsiella pneumoniae were found to be the most frequent bacterial isolates and non-Candida albicans for fungal isolates, respectively. Among the various antibiotics tested, most isolates were found to be resistant to third generation cephalosporins and penicillins, but susceptible to aminoglycoside Amikacin. On the other hand, production of ESBL and carbapenemase was found to be common among members of Enterobacteriaceae especially K. pneumoniae.

Underestimating the Impact of Ventilator-Associated Pneumonia by Use of Surveillance Data

We calculated rates of ventilator-associated pneumonia (VAP) by using surveillance data, clinical data, and coding data. Compared with the VAP rates calculated on the basis of surveillance data, the VAP rates calculated on the basis of coding data were significantly overestimated in 4 of 5 intensive, care units. Efforts to improve coding and clinical documentation will address much but not all of this discrepancy between surveillance and administrative data.

Prevalence and test characteristics of national health safety network ventilator-associated events

OBJECTIVES

The primary aim of the study was to measure the test characteristics of the National Health Safety Network ventilator-associated event/ventilator-associated condition constructs for detecting ventilator-associated pneumonia. Its secondary aims were to report the clinical features of patients with National Health Safety Network ventilator-associated event/ventilator-associated condition, measure costs of surveillance, and its susceptibility to manipulation.

DESIGN

Prospective cohort study.

SETTING

Two inpatient campuses of an academic medical center.

PATIENTS

Eight thousand four hundred eight mechanically ventilated adults discharged from an ICU.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The National Health Safety Network ventilator-associated event/ventilator-associated condition constructs detected less than a third of ventilator-associated pneumonia cases with a sensitivity of 0.325 and a positive predictive value of 0.07. Most National Health Safety Network ventilator-associated event/ventilator-associated condition cases (93%) did not have ventilator-associated pneumonia or other hospital-acquired complications; 71% met the definition for acute respiratory distress syndrome. Similarly, most patients with National Health Safety Network probable ventilator-associated pneumonia did not have ventilator-associated pneumonia because radiographic criteria were not met. National Health Safety Network ventilator-associated event/ventilator-associated condition rates were reduced 93% by an unsophisticated manipulation of ventilator management protocols.

CONCLUSIONS

The National Health Safety Network ventilator-associated event/ventilator-associated condition constructs failed to detect many patients who had ventilator-associated pneumonia, detected many cases that did not have a hospital complication, and were susceptible to manipulation. National Health Safety Network ventilator-associated event/ventilator-associated condition surveillance did not perform as well as ventilator-associated pneumonia surveillance and had several undesirable characteristics.

When policy gets it right: variability in u.s. Hospitals' diagnosis of ventilator-associated pneumonia*

OBJECTIVE

The Centers for Disease Control has recently proposed a major change in how ventilator-associated pneumonia is defined. This has profound implications for public reporting, reimbursement, and accountability measures for ICUs. We sought to provide evidence for or against this change by quantifying limitations of the national definition of ventilator-associated pneumonia that was in place until January 2013, particularly with regard to comparisons between, and ranking of, hospitals and ICUs.

DESIGN

A prospective survey of a nationally representative group of 43 hospitals, randomly selected from the American Hospital Association Guide (2009). Subjects classified six standardized vignettes of possible cases of ventilator-associated pneumonia as pneumonia or no pneumonia.

SUBJECTS

Individuals responsible for ventilator-associated pneumonia surveillance at 43 U.S. hospitals.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We measured the proportion of standardized cases classified as ventilator-associated pneumonia. Of 138 hospitals consented, 61 partially completed the survey and 43 fully completed the survey (response rate 44% and 31%, respectively). Agreement among hospitals about classification of cases as ventilator-associated pneumonia/not ventilator-associated pneumonia was nearly random (Fleiss κ 0.13). Some hospitals rated 0% of cases as having pneumonia; others classified 100% as having pneumonia (median, 50%; interquartile range, 33-66%). Although region of the country did not predict case assignment, respondents who described their region as "rural" were more likely to judge a case to be pneumonia than respondents elsewhere (relative risk, 1.25, Kruskal-Wallis chi-square, p = 0.03).

CONCLUSIONS

In this nationally representative study of hospitals, assignment of ventilator-associated pneumonia is extremely variable, enough to render comparisons between hospitals worthless, even when standardized cases eliminate variability in clinical data abstraction. The magnitude of this variability highlights the limitations of using poorly performing surveillance definitions as methods of hospital evaluation and comparison, and our study provides very strong support for moving to a more objective definition of ventilator-associated complications.

Diagnosis of ventilator-associated pneumonia: controversies and working toward a gold standard

PURPOSE OF REVIEW

The aim is to discuss the clinical, microbiologic, and radiological criteria used in the diagnosis of ventilator-associated pneumonia (VAP), distinguish between ventilator-associated tracheobronchitis (VAT) and VAP, and reconcile the proposed Centers for Disease Control surveillance criteria with clinical practice.

RECENT FINDINGS

Numerous ventilator-associated complications (VACs), including VAP and VAT, may occur in critically ill, intubated patients. A variety of definitions for identifying VAP have been proposed, but there is no diagnostic gold standard. The proposed surveillance definition will identify infectious and noninfectious VAC, including VAP and VAT, but this definition may be inadequate for clinical practice.

SUMMARY

The clinical characteristics of VAP and VAT are similar and include fever, leukocytosis, and purulent sputum. An infiltrate on chest radiograph is consistent with VAP but lacks diagnostic precision, so it is not a criterion in the proposed surveillance definition and should be interpreted cautiously by clinicians. Microbiologically, quantitative and semiquantitative endotracheal aspirate cultures may be employed to diagnose VAP and VAT. Positive bronchoalveolar lavage and protected specimen brush cultures are useful only for the diagnosis of VAP. Experts should collaborate to develop consensus definitions for VAP and VAT that can be applied in practice.

Incidence and outcomes of ventilator-associated tracheobronchitis and pneumonia

BACKGROUND

Prolonged intubation with mechanical ventilation carries a risk for ventilator-associated respiratory infections manifest as tracheobronchitis or pneumonia. This study analyzed natural history, incidence, and outcomes of patients developing ventilator-associated tracheobronchitis and pneumonia.

METHODS

We studied 188 mixed intensive care unit (ICU) patients intubated ≥48 hours for the development of tracheobronchitis defined as quantitative endotracheal aspirate ≥10(5) cfu/mL plus at least 2 clinical criteria (fever, leukocytosis, or purulent sputum). Pneumonia was defined as microbiologic criteria for tracheobronchitis and a new and persistent infiltrate on chest radiograph.

RESULTS

Airways of 41 (22%) patients became heavily colonized with a bacterial pathogen(s) at a concentration of ≥10(5) cfu/mL. Tracheobronchitis developed in 21 (11%) study patients, of which 6 (29%) later progressed to pneumonia. Including these 6 patients, 28 (15%) study patients developed pneumonia. Multidrug-resistant pathogens were isolated in 39% of pneumonia patients. Patients with tracheobronchitis and pneumonia had significantly more ventilator days and longer stays in the ICU (P ≤.02).

CONCLUSIONS

Approximately one third of tracheobronchitis patients later developed pneumonia. Patients with tracheobronchitis or pneumonia experienced significantly more ventilator days and longer ICU stays, but had no difference in mortality. Better patient outcomes and reduced health care costs may be achieved by earlier treatment of ventilator-associated respiratory infections, manifest as tracheobronchitis or pneumonia.

Variability in mean duration of mechanical ventilation among community hospitals

We explored intensive care units' mean ventilator-days per patient as a possible objective alternative to ventilator-associated pneumonia rates for assessing quality of care for ventilated patients. Mean ventilator-days per patient varied 4-fold within a network of community hospitals despite adjusting for multiple patient and hospital factors. Further assessment of this metric is warranted.

Agreement among health care professionals in diagnosing case Vignette-based surgical site infections

OBJECTIVE

To assess agreement in diagnosing surgical site infection (SSI) among healthcare professionals involved in SSI surveillance.

METHODS

Case-vignette study done in 2009 in 140 healthcare professionals from seven specialties (20 in each specialty, Anesthesiologists, Surgeons, Public health specialists, Infection control physicians, Infection control nurses, Infectious diseases specialists, Microbiologists) in 29 University and 36 non-University hospitals in France. We developed 40 case-vignettes based on cardiac and gastrointestinal surgery patients with suspected SSI. Each participant scored six randomly assigned case-vignettes before and after reading the SSI definition on an online secure relational database. The intraclass correlation coefficient (ICC) was used to assess agreement regarding SSI diagnosis on a seven-point Likert scale and the kappa coefficient to assess agreement for superficial or deep SSI on a three-point scale.

RESULTS

Based on a consensus, SSI was present in 21 of 40 vignettes (52.5%). Intraspecialty agreement for SSI diagnosis ranged across specialties from 0.15 (95% confidence interval, 0.00-0.59) (anesthesiologists and infection control nurses) to 0.73 (0.32-0.90) (infectious diseases specialists). Reading the SSI definition improved agreement in the specialties with poor initial agreement. Intraspecialty agreement for superficial or deep SSI ranged from 0.10 (-0.19-0.38) to 0.54 (0.25-0.83) (surgeons) and increased after reading the SSI definition only among the infection control nurses from 0.10 (-0.19-0.38) to 0.41 (-0.09-0.72). Interspecialty agreement for SSI diagnosis was 0.36 (0.22-0.54) and increased to 0.47 (0.31-0.64) after reading the SSI definition.

CONCLUSION

Among healthcare professionals evaluating case-vignettes for possible surgical site infection, there was large disagreement in diagnosis that varied both between and within specialties.

Public reporting of health care-associated infections (HAIs): approach to choosing HAI measures

OBJECTIVE

To develop a method for selecting health care-associated infection (HAI) measures for public reporting.

CONTEXT

HAIs are common, serious, and costly adverse outcomes of medical care that affect 2 million people in the United States annually. Thirty-seven states have introduced or passed legislation requiring public reporting of HAI measures. State legislation varies widely regarding which HAIs to report, how the data are collected and reported, and public availability of results.

DESIGN

The Maryland Health Care Commission developed an HAI Technical Advisory Committee (TAC) that consisted of a group of experts in the field of healthcare epidemiology, infection prevention and control (IPC), and public health. This group reviewed public reporting systems in other states, surveyed Maryland hospitals to determine the current state of IPC programs, performed a literature review on HAI measures, and developed six criteria for ranking the measures: impact, improvability, inclusiveness, frequency, functionality, and feasibility. The committee and experts in the field then ranked each of 18 proposed HAI measures. A composite score was determined for each measure.

RESULTS

Among outcome measures, the rate of central line-associated bloodstream infections ranked highest, followed by the rate of post-coronary artery bypass grafting surgical-site infections. Among process measures, perioperative antimicrobial prophylaxis, compliance with central-line bundles, compliance with hand hygiene, and healthcare-worker influenza vaccination ranked highest.

CONCLUSIONS

Our qualitative criteria facilitated consensus on the HAI TAC and provided a useful framework for public reporting of HAI measures. Validation will be important for such approaches to be supported by the scientific community.

Strategies for prevention of ventilator-associated pneumonia: bundles, devices, and medications for improved patient outcomes

Ventilator-associated pneumonia is associated with significant patient morbidity, mortality, and increased health care costs. In the current economic climate, it is crucial to implement cost-effective prevention strategies that have proven efficacy. Multiple prevention measures have been proposed by various expert panels. Global strategies have focused on infection control, and reduction of lower airway colonization with bacterial pathogens, intubation, duration of mechanical ventilation, and length of stay in the intensive care unit. Routine use of the Institute for Healthcare Improvement ventilator care bundle is widespread, and has been clearly demonstrated to be an effective method for reducing the incidence of ventilator-associated pneumonia. In this article, we examine specific aspects of the Institute for Healthcare Improvement bundle, better-designed endotracheal tubes, use of antibiotics and probiotics, and treatment of ventilator-associated tracheobronchitis to prevent ventilator-associated pneumonia.

Diagnosis of ventilator-associated respiratory infections (VARI): microbiologic clues for tracheobronchitis (VAT) and pneumonia (VAP)

Intubated patients are at risk of bacterial colonization and ventilator-associated respiratory infection (VARI). VARI includes tracheobronchitis (VAT) or pneumonia (VAP). VAT and VAP caused by multidrug-resistant (MDR) pathogens are increasing in the United States and Europe. In patients with risk factors for MDR pathogens, empiric antibiotics are often initiated for 48 to 72 hours pending the availability of pathogen identification and antibiotic sensitivity data. Extensive data indicate that early, appropriate antibiotic therapy improves outcomes for patients with VAP. Recognizing and treating VARI may allow earlier appropriate therapy and improved patient outcomes.

Prevention of VAP: is zero rate possible?

Infection prevention measures, specifically targeting ventilator-associated pneumonia (VAP), have been purposed as quality-of-care indicators for patients in intensive care units. The authors discuss some of the recent evidence of the prevention of nosocomial infections, with a particular emphasis on VAP. Moreover, there are several pitfalls in considering VAP rates as a safety indicator. Because of these limitations, the authors recommend the use of specific process measures, designed to reduce VAP, as the basis for interinstitutional benchmarking.

Multicenter evaluation of a novel surveillance paradigm for complications of mechanical ventilation

BACKGROUND

Ventilator-associated pneumonia (VAP) surveillance is time consuming, subjective, inaccurate, and inconsistently predicts outcomes. Shifting surveillance from pneumonia in particular to complications in general might circumvent the VAP definition's subjectivity and inaccuracy, facilitate electronic assessment, make interfacility comparisons more meaningful, and encourage broader prevention strategies. We therefore evaluated a novel surveillance paradigm for ventilator-associated complications (VAC) defined by sustained increases in patients' ventilator settings after a period of stable or decreasing support.

METHODS

We assessed 600 mechanically ventilated medical and surgical patients from three hospitals. Each hospital contributed 100 randomly selected patients ventilated 2-7 days and 100 patients ventilated >7 days. All patients were independently assessed for VAP and for VAC. We compared incidence-density, duration of mechanical ventilation, intensive care and hospital lengths of stay, hospital mortality, and time required for surveillance for VAP and for VAC. A subset of patients with VAP and VAC were independently reviewed by a physician to determine possible etiology.

RESULTS

Of 597 evaluable patients, 9.3% had VAP (8.8 per 1,000 ventilator days) and 23% had VAC (21.2 per 1,000 ventilator days). Compared to matched controls, both VAP and VAC prolonged days to extubation (5.8, 95% CI 4.2-8.0 and 6.0, 95% CI 5.1-7.1 respectively), days to intensive care discharge (5.7, 95% CI 4.2-7.7 and 5.0, 95% CI 4.1-5.9), and days to hospital discharge (4.7, 95% CI 2.6-7.5 and 3.0, 95% CI 2.1-4.0). VAC was associated with increased mortality (OR 2.0, 95% CI 1.3-3.2) but VAP was not (OR 1.1, 95% CI 0.5-2.4). VAC assessment was faster (mean 1.8 versus 39 minutes per patient). Both VAP and VAC events were predominantly attributable to pneumonia, pulmonary edema, ARDS, and atelectasis.

CONCLUSIONS

Screening ventilator settings for VAC captures a similar set of complications to traditional VAP surveillance but is faster, more objective, and a superior predictor of outcomes.

Management of ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) management depends on the interaction between the infective agent, the host response, and the antimicrobial drug used. After the pathogen reaches the lungs, two outcomes are possible: either the microorganisms are eliminated by the host immune system, or they overcome the immune system and cause pulmonary infection. When a patient is thought to have VAP, two steps are strongly recommended: etiologic diagnostic testing and the immediate initiation of antibiotics. The daily management of VAP remains a challenge for physicians in the ICU. In recent years, a more dynamic approach has evolved, updating local epidemiology, evaluating VAP and diagnostic tools every day, and assessing host response using clinical and biochemical parameters.

Successful prevention of ventilator-associated pneumonia in an intensive care setting

BACKGROUND

Ventilator-associated pneumonia (VAP) is one of the most common health care-associated infections (HAIs) in critical care settings.

OBJECTIVE

Our objective was to examine the effect of a series of interventions, implemented in 3 different periods to reduce the incidence of VAP in an intensive care unit (ICU).

METHODS

A quasiexperimental study was conducted in a medical-surgical ICU. Multiple interventions to optimize VAP prevention were performed during different phases. From March 2001 to December 2002 (phase 1: P1), some Centers for Disease Control and Prevention (CDC) evidence-based practices were implemented. From January 2003 to December 2006 (P2), we intervened in these processes at the same time that performance monitoring was occurring at the bedside, and, from January 2007 to September 2008 (P3), we continued P2 interventions and implemented the Institute for Healthcare Improvement's ventilator bundle plus oral decontamination with chlorhexidine and continuous aspiration of subglottic secretions.

RESULTS

The incidence density of VAP in the ICU per 1000 patient-days was 16.4 in phase 1, 15.0 in phase 2, and 10.4 in phase 3, P=.05. Getting to zero VAP was possible only in P3 when compliance with all interventions exceeded 95%.

CONCLUSION

These results suggest that reducing VAP rates to zero is a complex process that involves multiple performance measures and interventions.

Predicting the risk of documented ventilator-associated pneumonia for benchmarking: construction and validation of a score

OBJECTIVES

: To build and validate a ventilator-associated pneumonia risk score for benchmarking. The rate of ventilator-associated pneumonia varies widely with case-mix, a fact that has limited its use for measuring intensive care unit performance.

METHODS

: We studied 1856 patients in the OUTCOMEREA database treated at intensive care unit admission by endotracheal intubation followed by mechanical ventilation for >48 hrs; they were allocated randomly to a training data set (n = 1233) or a validation data set (n = 623). Multivariate logistic regression was used. Calibration of the final model was assessed in both data sets, using the Hosmer-Lemeshow chi-square test and receiver operating characteristic curves.

MEASUREMENTS AND MAIN RESULTS

: Independent risk factors for ventilator-associated pneumonia were male gender (odds ratio = 1.97, 95% confidence interval = 1.32-2.95); SOFA at intensive care unit admission (<3 [reference value], 3-4 [2.57, 1.39-4.77], 5-8 [7.37, 4.24-12.81], >8 [5.81 (3.2-10.52)], no use within 48 hrs after intensive care unit admission of parenteral nutrition (2.29, 1.52-3.45), no broad-spectrum antimicrobials (2.11, 1.46-3.06); and mechanical ventilation duration (<5 days (); 5-7 days (17.55, 4.01-76.85); 7-15 days (53.01, 12.74-220.56); >15 days (225.6, 54.3-936.7). Tests in the training set showed good calibration and good discrimination (area under the curve-receiver operating characteristic curve = 0.881), and both criteria remained good in the validation set (area under the curve-receiver operating characteristic curve = 0.848) and good calibration (Hosmer-Lemeshow chi-square = 9.98, p = .5). Observed ventilator-associated pneumonia rates varied across intensive care units from 9.7 to 26.1 of 1000 mechanical ventilation days but the ratio of observed over theoretical ventilator-associated pneumonia rates was >1 in only two intensive care units.

CONCLUSIONS

: The ventilator-associated pneumonia rate may be useful for benchmarking provided the ratio of observed over theoretical rates is used. External validation of our prediction score is needed.

Ventilator-associated infection

PURPOSE OF REVIEW

Ventilator-associated pneumonia (VAP) is the most serious and controversial of the infections of the critically ill patient. The accuracy of standard methods of diagnosis remains under constant scrutiny, and at the same time there is increasing debate about whether it is a preventable disease. This review focuses on the pathophysiology of respiratory tract infection in the ventilated patient, and how the latest advances have grown from our current understanding of its pathogenesis.

RECENT FINDINGS

Data from many recent investigations have focused on the role of proximal airway infection, ventilator-associated tracheobronchitis (VAT), in respiratory tract infection. The goals of recent trials include reducing the morbidity associated with the progression of airway colonization to VAT or with the progression of VAT to VAP. Continuous subglottic secretion suctioning, innovative types of endotracheal tubes and targeted therapy for VAT in recent investigations have shown promise in improving clinical outcomes in the critically ill patient. However, even with diligent attention to all the modifiable risk factors for respiratory infection, complete elimination of VAT and VAP remains unlikely. As long as a patient requires an endotracheal tube that disturbs airway integrity, host defenses will be impaired, and resistant virulent organisms that result from our liberal use of systemic antibiotics will continue to challenge critical care specialists.

SUMMARY

This review will focus on: the current understanding of the pathogenesis of VAT and VAP, modifiable risk factors and new approaches to treatment, and bacterial resistance challenges.