Eight initiatives that misleadingly lower ventilator-associated pneumonia rates

Temporal trends in postoperative and ventilator-associated pneumonia in the United States

OBJECTIVE

To determine change in rates of postoperative pneumonia and ventilator-associated pneumonia among patients hospitalized in the United States during 2009-2019.

DESIGN

Retrospective cohort study.

PATIENTS

Patients hospitalized for major surgical procedures, acute myocardial infarction, heart failure, and pneumonia.

METHODS

We conducted a retrospective review of data from the Medicare Patient Safety Monitoring System, a chart-abstraction-derived database including 21 adverse-event measures among patients hospitalized in the United States. Changes in observed and risk-adjusted rates of postoperative pneumonia and ventilator-associated pneumonia were derived.

RESULTS

Among 58,618 patients undergoing major surgical procedures between 2009 and 2019, the observed rate of postoperative pneumonia from 2009-2011 was 1.9% and decreased to 1.3% during 2017-2019. The adjusted annual risk each year, compared to the prior year, was 0.94 (95% CI, 0.92-0.96). Among 4,007 patients hospitalized for any of these 4 conditions at risk for ventilator-associated pneumonia during 2009-2019, we did not detect a significant change in observed or adjusted rates. Observed rates clustered around 10%, and adjusted annual risk compared to the prior year was 0.99 (95% CI, 0.95-1.02).

CONCLUSIONS

During 2009-2019, the rate of postoperative pneumonia decreased statistically and clinically significantly in among patients hospitalized for major surgical procedures in the United States, but rates of ventilator-associated pneumonia among patients hospitalized for major surgical procedures, acute myocardial infarction, heart failure, and pneumonia did not change.

Strategies to prevent ventilator-associated pneumonia, ventilator-associated events, and nonventilator hospital-acquired pneumonia in acute-care hospitals: 2022 Update

The purpose of this document is to highlight practical recommendations to assist acute care hospitals to prioritize and implement strategies to prevent ventilator-associated pneumonia (VAP), ventilator-associated events (VAE), and non-ventilator hospital-acquired pneumonia (NV-HAP) in adults, children, and neonates. This document updates the Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals published in 2014. This expert guidance document is sponsored by the Society for Healthcare Epidemiology (SHEA), and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America, the American Hospital Association, the Association for Professionals in Infection Control and Epidemiology, and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise.

Ventilator-associated pneumonia in critically ill patients with COVID-19 infection, a narrative review

COVID pneumonitis can cause patients to become critically ill. They may require intensive care and mechanical ventilation. Ventilator-associated pneumonia is a concern. This review aims to discuss the topic of ventilator-associated pneumonia in this group. Several reasons have been proposed to explain the elevated rates of VAP in critically ill COVID patients compared to non-COVID patients. Extrinsic factors include understaffing, lack of PPE and use of immunomodulating agents. Intrinsic factors include severe parenchymal damage, immune dysregulation, along with pulmonary vascular endothelial inflammation and thrombosis. The rate of VAP has been reported at 45.4%, with an ICU mortality rate of 42.7%. Multiple challenges to diagnosis exist. Other conditions such as acute respiratory distress syndrome, pulmonary oedema and atelectasis can present with similar features. Frequent growth of gram-negative bacteria has been shown in multiple studies, with particularly high rates of pseudomonas aeruginosa. The rate of invasive pulmonary aspergillosis has been reported at 4–30%. We would recommend the use of invasive techniques when possible. This will enable de-escalation of antibiotics as soon as possible, decreasing overuse. It is also important to keep other possible causes of ventilator-associated pneumonia in mind, such as COVID-19 associated pulmonary aspergillosis, cytomegalovirus, etc. Diagnostic tests such as galactomannan and B-D-glucan should be considered. These patients may face a long treatment course, with risk of re-infection, along with prolonged weaning, which carries its own long-term consequences.

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.

Ventilator-Associated Pneumonia

Ventilator-associated pneumonia occurs in patients who have been intubated for at least 2–3 days with significant exposure to hospital-acquired organisms. Treatment should be initiated rapidly and cover Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, and methicillin-resistant Staphylococcus aureus(MRSA). Within 72 h or with the availability of culture results, antibiotics should be narrowed. Active research is on-going to identify patients at risk for ventilator-associated complications and to minimize the likelihood of infection in these patients.

Ventilator Bundle Compliance and Risk of Ventilator-Associated Events

OBJECTIVE

Ventilator bundles encompass practices that reduce the risk of ventilator complications, including ventilator-associated pneumonia. The impact of ventilator bundles on the risk of developing ventilator-associated events (VAEs) is unknown. We sought to determine whether decreased compliance to the ventilator bundle increases the risk for VAE development.

DESIGN

Nested case-control study.

SETTING

This study was conducted at 6 adult intensive care units at an academic tertiary-care center in Tennessee.

PATIENTS

In total, 273 patients with VAEs were randomly matched in a 1:4 ratio to controls by mechanical ventilation duration and ICU type.

METHODS

Controls were selected from the primary study population at risk for a VAE after being mechanically ventilated for the same number of days as a specified case. Using conditional logistic regression analysis, overall cumulative compliance, and compliance with individual components of the bundle in the 3 and 7 days prior to VAE development (or the control match day) were examined.

RESULTS

Overall bundle compliance at 3 days (odds ratio [OR], 1.15; P=.34) and 7 days prior to VAE diagnosis (OR, 0.96; P=.83) were not associated with VAE development. This finding did not change when limiting the outcome to infection-related ventilator-associated complications (IVACs) and after adjusting for age and gender. In the examination of compliance with specific bundle components increased compliance with chlorhexidine oral care was associated with increased risk of VAE development in all analyses.

CONCLUSIONS

Ventilator bundle compliance was not associated with a reduced risk for VAEs. Higher compliance with chlorhexidine oral care was associated with a greater risk for VAE development.

Infect Control Hosp Epidemiol 2018;39:637–643

Quelle surveillance des infections associées aux soins en réanimation en 2018 ?

La surveillance des infections associées aux soins (IAS) est prioritaire en réanimation, secteur à haut risque du fait de l’état critique des patients et de leur exposition aux dispositifs invasifs. Elle présente un triple objectif : décrire l’épidémiologie et l’incidence des IAS ; évaluer l’impact des actions de prévention ou de contrôle et alerter face à une épidémie ou des phénomènes émergents. Cette surveillance des IAS peut être réalisée selon une méthodologie interne, définie par l’établissement, ou intégrée à un réseau de surveillance. L’intérêt de la surveillance pour la prévention des IAS en réanimation n’est plus à démontrer, mais la surveillance manuelle reste chronophage pour les cliniciens et les équipes d’hygiène, limitant ainsi le temps dédié à la prévention de ces infections. La surveillance automatisée apparaît aujourd’hui comme un outil intéressant, tant par ses performances que par le gain de temps qu’elle représente pour les équipes. Plusieurs éléments sont primordiaux pour obtenir des résultats fiables : la nécessité d’une harmonisation des définitions et des méthodes de surveillance ; la mise à disposition d’outils informatiques performants pour faciliter le suivi des patients ; le leadership des réanimateurs dans la surveillance. Cet article fait le point sur les méthodes de surveillance des IAS utilisées aujourd’hui en réanimation, l’intérêt de la mise en place de cette surveillance épidémiologique ainsi que la fiabilité des données recueillies et, enfin, les avantages du développement d’une surveillance semi-automatisée ou automatisée des IAS dans ce secteur.

Impact of the Antibiotic Stewardship Program on Prevention and Control of Surgical Site Infection during Peri-Operative Clean Surgery

BACKGROUND

Surgical site infections (SSIs) are the leading cause of hospital-acquired infections and are associated with substantial healthcare costs, with increased morbidity and mortality. To investigate the effects of the antibiotic stewardship program on prevention and control of SSI during clean surgery, we investigated this situation in our institution.

PATIENTS AND METHODS

We performed a quasi-experimental study to compare the effect before and after the antibiotic stewardship program intervention. During the pre-intervention stage (January 1, 2010 through December 31, 2011), comprehensive surveillance was performed to determine the SSI baseline data. In the second stage (January 1, 2012 through December 31, 2016), an infectious diseases physician and an infection control practitioner identified the surgical patients daily and followed up on the duration of antimicrobial prophylaxis.

RESULTS

From January 1, 2010 to December 31, 2016, 41,426 patients underwent clean surgeries in a grade III, class A hospital. The rate of prophylactic antibiotic use in the 41,426 clean surgeries was reduced from 82.9% to 28.0% after the interventions. The rate of antibiotic agents administered within 120 minutes of the first incision increased from 20.8% to 85.1%. The rate at which prophylactic antimicrobial agents were discontinued in the first 24 hours after surgery increased from 22.1% to 60.4%. Appropriate antibiotic selection increased from 37.0% to 93.6%. Prophylactic antibiotic re-dosing increased from 3.8% to 64.8%. The SSI rate decreased from 0.7% to 0.5% (p < 0.05). The pathogen detection rate increased from 16.7% up to 41.8% after intervention. The intensity of antibiotic consumption reduced from 74.9 defined daily doses (DDDs) per 100 bed-days to 34.2 DDDs per 100 bed-days after the interventions.

CONCLUSION

Long-term and continuous antibiotic stewardship programs have important effects on the prevention and control of SSI during clean surgery.

Antibiotic consumption and ventilator-associated pneumonia rates, some parallelism but some discrepancies

Ventilator-associated pneumonia (VAP) is a common infection in intensive care units (ICUs) but its clinical definition is neither sensitive nor specific and lacks accuracy and objectivity. New defining criteria were proposed in 2013 by the National Healthcare Safety Network (NHSN) in order to more accurately conduct surveillance and track prevention progress. Although there is a consistent trend towards a decrease in VAP incidence during the last decade, significant differences in VAP rates have been reported and are persistently lower in NHSN and other American reports (0.0 to 4.4 VAP per 1,000 ventilator-days in 2012) compared to the European Centre for Disease Prevention and Control (ECDC) data (10 VAP per 1,000 ventilator-days in 2014). In the United States, VAP has been proposed as an indicator of quality of care in public reporting, and the threat of financial penalties for this diagnosis has put pressure on hospitals to minimize VAP rates that may lead to artificial lower values, independently of patient care. Although prevention bundles may contribute for encouraging reductions in VAP incidence, both pathophysiologic and epidemiologic factors preclude a zero-VAP rate. It would be expected from the trend of reduction of VAP incidence that the consumption of antibiotics would also decrease in particular in those hospitals with lowest VAP rates. However, ICU reports show a steadily use of antibiotics for nosocomial pneumonia in 15% of patients and both ECDC and NHSN data on antibiotic consumption showed no significant trend. Knowledge of bacterial epidemiology and resistance profiles for each ICU has great relevance in order to understand trends of antibiotic use. The new NHSN criteria provide a more objective and quantitative data based VAP definition, including an antibiotic administration criterion, allowing, in theory, a more comprehensive assessment and a reportable benchmark of the observed VAP and antibiotic consumption variability.

Ventilator-Associated Events and Their Prevention

The Centers for Disease Control and Prevention shifted the focus of safety surveillance in mechanically ventilated patients from ventilator-associated pneumonia to ventilator-associated events (VAEs) in 2013. The shift was designed to increase the objectivity and reproducibility of surveillance and to encourage quality-improvement programs to tackle a broader array of complications in mechanically ventilated patients. Prospective intervention studies have found that minimizing sedation, increasing the use of spontaneous awakening and breathing trials, and conservative fluid management can lower VAE rates and decrease duration of mechanical ventilation. Additional strategies to prevent VAEs include early mobility programs, low tidal volume ventilation, and restrictive transfusion thresholds.

Ventilator-Associated Pneumonia and Other Complications

Ventilator-associated pneumonia occurs in patients who have been intubated for two to three days with significant exposure to hospital-acquired organisms. Treatment should be initiated rapidly and cover P. aeruginosa, Escheriochia coli, Klebsiella pneumonia, and Acinetobacter species as well as methicillin-resistant S. aureus. Within 72 h or with the availability of culture results, antibiotics should be narrowed. Active research is on-going to identify patients at risk for ventilator-associated complications and to minimize the likelihood of infection in these patients.

Ventilator-associated pneumonia rates in critical care units in 3 Arabian Gulf countries: A 6-year surveillance study

BACKGROUND

Data estimating the rates of ventilator-associated pneumonia (VAP) in critical patients in Gulf Cooperation Council (GCC) countries are very limited. The aim of this study was to estimate VAP rates in GCC hospitals and to compare rates with published reports of the U.S. National Healthcare Safety Network (NHSN) and International Nosocomial Infection Control Consortium (INICC).

METHODS

VAP rates and ventilator utilization between 2008 and 2013 were calculated from aggregate VAP surveillance data using NHSN methodology pooled from 6 hospitals in 3 GCC countries: Saudi Arabia, Oman, and Bahrain. The standardized infection ratios of VAP in GCC hospitals were compared with published reports of the NHSN and INICC.

RESULTS

A total of 368 VAP events were diagnosed during a 6-year period covering 76,749 ventilator days and 134,994 patient days. The overall VAP rate was 4.8 per 1,000 ventilator days (95% confidence interval, 4.3-5.3), with an overall ventilator utilization of 0.57. The VAP rates showed a wide variability between different types of intensive care units (ICUs) and were decreasing over time. After adjusting for the differences in ICU type, the risk of VAP in GCC hospitals was 217% higher than NHSN hospitals and 69% lower than INICC hospitals.

CONCLUSIONS

The risk of VAP in ICU patients in GCC countries is higher than pooled U.S. VAP rates but lower than pooled rates from developing countries participating in the INICC.

Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals: 2014 Update

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format to assist acute care hospitals in implementing and prioritizing strategies to prevent ventilator-associated pneumonia (VAP) and other ventilator-associated events (VAEs) and to improve outcomes for mechanically ventilated adults, children, and neonates. This document updates "Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals," published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.

Validation of an automated surveillance approach for drain-related meningitis: a multicenter study

OBJECTIVE Manual surveillance of healthcare-associated infections is cumbersome and vulnerable to subjective interpretation. Automated systems are under development to improve efficiency and reliability of surveillance, for example by selecting high-risk patients requiring manual chart review. In this study, we aimed to validate a previously developed multivariable prediction modeling approach for detecting drain-related meningitis (DRM) in neurosurgical patients and to assess its merits compared to conventional methods of automated surveillance. METHODS Prospective cohort study in 3 hospitals assessing the accuracy and efficiency of 2 automated surveillance methods for detecting DRM, the multivariable prediction model and a classification algorithm, using manual chart review as the reference standard. All 3 methods of surveillance were performed independently. Patients receiving cerebrospinal fluid drains were included (2012-2013), except children, and patients deceased within 24 hours or with pre-existing meningitis. Data required by automated surveillance methods were extracted from routine care clinical data warehouses. RESULTS In total, DRM occurred in 37 of 366 external cerebrospinal fluid drainage episodes (12.3/1000 drain days at risk). The multivariable prediction model had good discriminatory power (area under the ROC curve 0.91-1.00 by hospital), had adequate overall calibration, and could identify high-risk patients requiring manual confirmation with 97.3% sensitivity and 52.2% positive predictive value, decreasing the workload for manual surveillance by 81%. The multivariable approach was more efficient than classification algorithms in 2 of 3 hospitals. CONCLUSIONS Automated surveillance of DRM using a multivariable prediction model in multiple hospitals considerably reduced the burden for manual chart review at near-perfect sensitivity.

Assessment of an automated surveillance system for detection of initial ventilator-associated events

Surveillance for initial ventilator-associated events (VAEs) was automated and compared with nonautomated review of episodes of mechanical ventilation. Sensitivity, specificity, positive predictive value, and negative predictive value of automated surveillance were very high (>93%), and automated surveillance reduced the time spent on detection of VAEs by >90%.

Ventilator-associated Pneumonia caused by commensal oropharyngeal Flora; [corrected] a retrospective Analysis of a prospectively collected Database

Background

The significance of commensal oropharyngeal flora (COF) as a potential cause of ventilator-associated pneumonia (VAP) is scarcely investigated and consequently unknown. Therefore, the aim of this study was to explore whether COF may cause VAP.

Methods

Retrospective clinical, microbiological and radiographic analysis of all prospectively collected suspected VAP cases in which bronchoalveolar lavage fluid exclusively yielded ≥ 10⁴ cfu/ml COF during a 9.5-year period. Characteristics of 899 recent intensive care unit (ICU) admissions were used as a reference population.

Results

Out of the prospectively collected database containing 159 VAP cases, 23 patients were included. In these patients, VAP developed after a median of 8 days of mechanical ventilation. The patients faced a prolonged total ICU length of stay (35 days [P < .001]), hospital length of stay (45 days [P = .001]), and a trend to higher mortality (39 % vs. 26 %, [P = .158]; standardized mortality ratio 1.26 vs. 0.77, [P = .137]) compared to the reference population. After clinical, microbiological and radiographic analysis, COF was the most likely cause of respiratory deterioration in 15 patients (9.4 % of all VAP cases) and a possible cause in 2 patients.

Conclusion

Commensal oropharyngeal flora appears to be a potential cause of VAP in limited numbers of ICU patients as is probably associated with an increased length of stay in both ICU and hospital. As COF-VAP develops late in the course of ICU admission, it is possibly associated with the immunocompromised status of ICU patients.

Sustained Reduction of Ventilator-Associated Pneumonia Rates Using Real-Time Course Correction With a Ventilator Bundle Compliance Dashboard

BACKGROUND

The effectiveness of practice bundles on reducing ventilator-associated pneumonia (VAP) has been questioned.

OBJECTIVE

To implement a comprehensive program that included a real-time bundle compliance dashboard to improve compliance and reduce ventilator-associated complications. DESIGN Before-and-after quasi-experimental study with interrupted time-series analysis. SETTING Academic medical center.

METHODS

In 2007 a comprehensive institutional ventilator bundle program was developed. To assess bundle compliance and stimulate instant course correction of noncompliant parameters, a real-time computerized dashboard was developed. Program impact in 6 adult intensive care units (ICUs) was assessed. Bundle compliance was noted as an overall cumulative bundle adherence assessment, reflecting the percentage of time all elements were concurrently in compliance for all patients.

RESULTS

The VAP rate in all ICUs combined decreased from 19.5 to 9.2 VAPs per 1,000 ventilator-days following program implementation (P<.001). Bundle compliance significantly increased (Z100 score of 23% in August 2007 to 83% in June 2011 [P<.001]). The implementation resulted in a significant monthly decrease in the overall ICU VAP rate of 3.28/1,000 ventilator-days (95% CI, 2.64-3.92/1,000 ventilator-days). Following the intervention, the VAP rate decreased significantly at a rate of 0.20/1,000 ventilator-days per month (95% CI, 0.14-0.30/1,000 ventilator-days per month). Among all adult ICUs combined, improved bundle compliance was moderately correlated with monthly VAP rate reductions (Pearson correlation coefficient, -0.32).

CONCLUSION

A prevention program using a real-time bundle adherence dashboard was associated with significant sustained decreases in VAP rates and an increase in bundle compliance among adult ICU patients.

Strategies to prevent ventilator-associated pneumonia in acute care hospitals: 2014 update

Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format to assist acute care hospitals in implementing and prioritizing strategies to prevent ventilator-associated pneumonia (VAP) and other ventilator-associated events (VAEs) and to improve outcomes for mechanically ventilated adults, children, and neonates. This document updates “Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals,” published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates.

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.

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.

Risk factors for ventilator-associated events: a case-control multivariable analysis

OBJECTIVES

The Centers for Disease Control and Prevention recently released new surveillance definitions for ventilator-associated events, including the new entities of ventilator-associated conditions and infection-related ventilator-associated complications. Both ventilator-associated conditions and infection-related ventilator-associated complications are associated with prolonged mechanical ventilation and hospital death, but little is known about their risk factors and how best to prevent them. We sought to identify risk factors for ventilator-associated conditions and infection-related ventilator-associated complications.

DESIGN

Retrospective case-control study.

SETTING

Medical, surgical, cardiac, and neuroscience units of a tertiary care teaching hospital.

PATIENTS

Hundred ten patients with ventilator-associated conditions matched to 110 controls without ventilator-associated conditions on the basis of age, sex, ICU type, comorbidities, and duration of mechanical ventilation prior to ventilator-associated conditions.

INTERVENTIONS

None.

MEASUREMENTS

We compared cases with controls with regard to demographics, comorbidities, ventilator bundle adherence rates, sedative exposures, routes of nutrition, blood products, fluid balance, and modes of ventilatory support. We repeated the analysis for the subset of patients with infection-related ventilator-associated complications and their controls.

MAIN RESULTS

Case and control patients were well matched on baseline characteristics. On multivariable logistic regression, significant risk factors for ventilator-associated conditions were mandatory modes of ventilation (odds ratio, 3.4; 95% CI, 1.6-8.0) and positive fluid balances (odds ratio, 1.2 per L positive; 95% CI, 1.0-1.4). Possible risk factors for infection-related ventilator-associated complications were starting benzodiazepines prior to intubation (odds ratio, 5.0; 95% CI, 1.3-29), total opioid exposures (odds ratio, 3.3 per 100 μg fentanyl equivalent/kg; 95% CI, 0.90-16), and paralytic medications (odds ratio, 2.3; 95% CI, 0.79-80). Traditional ventilator bundle elements, including semirecumbent positioning, oral care with chlorhexidine, venous thromboembolism prophylaxis, stress ulcer prophylaxis, daily spontaneous breathing trials, and sedative interruptions, were not associated with ventilator-associated conditions or infection-related ventilator-associated complications.

CONCLUSIONS

Mandatory modes of ventilation and positive fluid balance are risk factors for ventilator-associated conditions. Benzodiazepines, opioids, and paralytic medications are possible risk factors for infection-related ventilator-associated complications. Prospective studies are needed to determine if targeting these risk factors can lower ventilator-associated condition and infection-related ventilator-associated complication rates.

Electronic implementation of a novel surveillance paradigm for ventilator-associated events. Feasibility and validation

RATIONALE

Accurate surveillance of ventilator-associated pneumonia (VAP) is hampered by subjective diagnostic criteria. A novel surveillance paradigm for ventilator-associated events (VAEs) was introduced.

OBJECTIVES

To determine the validity of surveillance using the new VAE algorithm.

METHODS

Prospective cohort study in two Dutch academic medical centers (2011-2012). VAE surveillance was electronically implemented and included assessment of (infection-related) ventilator-associated conditions (VAC, IVAC) and VAP. Concordance with ongoing prospective VAP surveillance was assessed, along with clinical diagnoses underlying VAEs and associated mortality of all conditions. Consequences of minor differences in electronic VAE implementation were evaluated.

MEASUREMENTS AND MAIN RESULTS

The study included 2,080 patients with 2,296 admissions. Incidences of VAC, IVAC, VAE-VAP, and VAP according to prospective surveillance were 10.0, 4.2, 3.2, and 8.0 per 1000 ventilation days, respectively. The VAE algorithm detected at most 32% of the patients with VAP identified by prospective surveillance. VAC signals were most often caused by volume overload and infections, but not necessarily VAP. Subdistribution hazards for mortality were 3.9 (95% confidence interval, 2.9-5.3) for VAC, 2.5 (1.5-4.1) for IVAC, 2.0 (1.1-3.6) for VAE-VAP, and 7.2 (5.1-10.3) for VAP identified by prospective surveillance. In sensitivity analyses, mortality estimates varied considerably after minor differences in electronic algorithm implementation.

CONCLUSIONS

Concordance between the novel VAE algorithm and VAP was poor. Incidence and associated mortality of VAE were susceptible to small differences in electronic implementation. More studies are needed to characterize the clinical entities underlying VAE and to ensure comparability of rates from different institutions.

Assessing the impact of an educational intervention on ventilator-associated pneumonia in a pediatric critical care unit

BACKGROUND

Ongoing educational programs targeting health care professionals have shown positive outcomes by reducing the morbidity and mortality associated with health care-associated infections (HAIs). We undertook this study to measure the impact of such a program in a pediatric critical care unit of a developing country.

METHODS

This prospective study was conducted in 2 time periods of 6 months each, with an educational intervention for resident doctors and nurses in between. The rates of ventilator-associated pneumonia (VAP) during the preintervention and postintervention periods were estimated by active surveillance.

RESULTS

The incidence density of VAP was reduced by 28% (20.2 vs 14.6 per 1,000 ventilator-days; P = .21, Z test) despite a significant increase in the ventilator utilization ratio during the postintervention period (0.64 vs 0.88; P < .0001, Pearson's χ² test). There was a statistically significant reduction in mortality among patients who received mechanical ventilation for ≥48 hours in the postintervention period (49.3% vs 31.4%; P = .029, Pearson's χ² test).

CONCLUSIONS

Educational programs have a positive impact on reducing the morbidity and mortality associated with HAIs. Incidence rates based on device-days should be compared by keeping the variations in device utilization ratio in mind.

Developing a new, national approach to surveillance for ventilator-associated events*

OBJECTIVE

To develop and implement an objective, reliable approach to surveillance for ventilator-associated events in adult patients.

DESIGN

The Centers for Disease Control and Prevention (CDC) convened a Ventilator-Associated Pneumonia (VAP) Surveillance Definition Working Group in September 2011. Working Group members included representatives of stakeholder societies and organizations and federal partners.

MAIN RESULTS

The Working Group finalized a three-tier, adult surveillance definition algorithm for ventilator-associated events. The algorithm uses objective, readily available data elements and can identify a broad range of conditions and complications occurring in mechanically ventilated adult patients, including but not limited to VAP. The first tier definition, ventilator-associated condition (VAC), identifies patients with a period of sustained respiratory deterioration following a sustained period of stability or improvement on the ventilator, defined by changes in the daily minimum fraction of inspired oxygen or positive end-expiratory pressure. The second tier definition, infection-related ventilator-associated complication (IVAC), requires that patients with VAC also have an abnormal temperature or white blood cell count, and be started on a new antimicrobial agent. The third tier definitions, possible and probable VAP, require that patients with IVAC also have laboratory and/or microbiological evidence of respiratory infection.

CONCLUSIONS

Ventilator-associated events surveillance was implemented in January 2013 in the CDC's National Healthcare Safety Network. Modifications to improve surveillance may be made as additional data become available and users gain experience with the new definitions.

Towards zero rate in healthcare-associated infections: one size shall not fit all

ICU patients are identified as targets for quality of care and patient safety improvement strategies. Critically ill patients are at high risk for complications due to the complex and invasive nature of critical care. Several reports in the literature describe initiatives aiming to zero the healthcare-associated infection rate. We discuss the results of a study assessing a systematic team approach with very aggressive interventions surrounding the Institute for Healthcare Improvement Central Line-associated Blood Stream Infection bundle, which obtained a successful reduction of the rates. In addition, we discuss why some healthcare-associated infections are not fully preventable and the different reasons for this, the identification of which would be a cornerstone of quality improvement and safety promotion initiatives in critically ill patients.

Automated surveillance for healthcare-associated infections: opportunities for improvement

Surveillance of healthcare-associated infections is a cornerstone of infection prevention programs, and reporting of infection rates is increasingly required. Traditionally, surveillance is based on manual medical records review; however, this is very labor intensive and vulnerable to misclassification. Existing electronic surveillance systems based on classification algorithms using microbiology results, antibiotic use data, and/or discharge codes have increased the efficiency and completeness of surveillance by preselecting high-risk patients for manual review. However, shifting to electronic surveillance using multivariable prediction models based on available clinical patient data will allow for even more efficient detection of infection. With ongoing developments in healthcare information technology, implementation of the latter surveillance systems will become increasingly feasible. As with current predominantly manual methods, several challenges remain, such as completeness of postdischarge surveillance and adequate adjustment for underlying patient characteristics, especially for comparison of healthcare-associated infection rates across institutions.

Quantitative cultures of bronchoscopically obtained specimens should be performed for optimal management of ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) is a leading cause of health care-associated infection. It has a high rate of attributed mortality, and this mortality is increased in patients who do not receive appropriate empirical antimicrobial therapy. As a result of the overuse of broad-spectrum antimicrobials such as the carbapenems, strains of Acinetobacter, Enterobacteriaceae, and Pseudomonas aeruginosa susceptible only to polymyxins and tigecycline have emerged as important causes of VAP. The need to accurately diagnose VAP so that appropriate discontinuation or de-escalation of antimicrobial therapy can be initiated to reduce this antimicrobial pressure is essential. Practice guidelines for the diagnosis of VAP advocate the use of bronchoalveolar lavage (BAL) fluid obtained either bronchoscopically or by the use of a catheter passed through the endotracheal tube. The CDC recommends that quantitative cultures be performed on these specimens, using ≥ 10(4) CFU/ml to designate a positive culture (http://www.cdc.gov/nhsn/TOC_PSCManual.html, accessed 30 October 2012). However, there is no consensus in the clinical microbiology community as to whether these specimens should be cultured quantitatively, using the aforementioned designated bacterial cell count to designate infection, or by a semiquantitative approach. We have asked Vickie Baselski, University of Tennessee Health Science Center, who was the lead author on one of the seminal papers on quantitative BAL fluid culture, to explain why she believes that quantitative BAL fluid cultures are the optimal strategy for VAP diagnosis. We have Stacey Klutts, University of Iowa, to advocate the semiquantitative approach.

Advancing the science of ventilator-associated pneumonia surveillance

The landmark Study on the Efficacy of Nosocomial Infection Control definitively demonstrated that infection surveillance and control programs prevent hospital-acquired infections. The rise of public reporting, benchmarking, and pay for performance movements, however, has considerably changed the infection surveillance landscape in the 27 years since this study was published. Clinically nuanced surveillance definitions that served the profession well for many years have fallen into disfavor because their complexity and subjectivity allow for conscious and subconscious gaming. These limitations make it very difficult to determine whether changes in surveillance rates represent true changes in disease incidence or artifacts of definition subjectivity, external reporting pressures, and internal biases. Surveillance definitions need to be revised to enhance objectivity and to ensure that they detect clinically meaningful events associated with compromised outcomes. The US Centers for Disease Control and Prevention recently released modified definitions for ventilator-associated events that have the potential to make safety surveillance for ventilated patients more credible and useful once again.