Automated surveillance for ventilator-associated events

Ventilator-Associated Pneumonia, Ventilator-Associated Events, and Nosocomial Respiratory Viral Infections on the Leeside of the Pandemic

The COVID-19 pandemic has had an unprecedented impact on population health and hospital operations. Over 7 million patients have been hospitalized for COVID-19 thus far in the United States alone. Mortality rates for hospitalized patients during the first wave of the pandemic were > 30%, but as we enter the fifth year of the pandemic hospitalizations have fallen and mortality rates for hospitalized patients with COVID-19 have plummeted to 5% or less. These gains reflect lessons learned about how to optimize respiratory support for different kinds of patients, targeted use of therapeutics for patients with different manifestations of COVID-19 including immunosuppressants and antivirals as appropriate, and high levels of population immunity acquired through vaccines and natural infections. At the same time, the pandemic has helped highlight some longstanding sources of harm for hospitalized patients including hospital-acquired pneumonia, ventilator-associated events (VAEs), and hospital-acquired respiratory viral infections. We are, thankfully, on the leeside of the pandemic at present; but the large increases in ventilator-associated pneumonia (VAP), VAEs, bacterial superinfections, and nosocomial respiratory viral infections associated with the pandemic beg the question of how best to prevent these complications moving forward. This paper reviews the burden of hospitalization for COVID-19, the intersection between COVID-19 and both VAP and VAEs, the frequency and impact of hospital-acquired respiratory viral infections, new recommendations on how best to prevent VAP and VAEs, and current insights into effective strategies to prevent nosocomial spread of respiratory viruses.

Ventilator-Associated Events Cost in ICU Patients Receiving Mechanical Ventilation: A Multi-State Model

Introduction

Cost analysis is complicated by the fact that patients acquire infections during their hospital stay, having already spent time at risk without having an infection. Multi-state models (MSM) accounts for this time at risk treating infections as time-dependent exposures from ICU admission.

Aim of the study

To estimate ventilator-associated events (VAEs) direct additional cost in ICU patients.

Material and Methods

This was a prospective, observational study carried out for a two-year period in four medical-surgical ICUs of Athens, Greece. The sample consisted of adult patients who received mechanical ventilation for ≥4 days and were followed until discharge from the ICU or until death. CDC standard definitions were used to diagnose VAEs. To estimate VAEs additional length of stay (LOS), we used a four-state model that accounted for the time of VAEs. The direct hospital cost was calculated, consisting of the fixed and variable cost. The direct additional cost per VAEs episode was calculated by multiplying VAEs extra LOS by cost per day of ICU hospitalization.

Results

In the final analysis were included 378 patients with 9,369 patient-days. The majority of patients were male (58.7%) with a median age of 60 years. Of 378 patients 143 (37.8%) developed 143 episodes of VAEs. VAEs crude additional LOS was 17 days, while VAE mean additional LOS after applying MSM was 6.55±1.78 days. The direct cost per day of ICU hospitalization was € 492.80. The direct additional cost per VAEs episode was € 3,227.84, € 885.56 the fixed and € 2,342.28 the variable cost. Antibiotic cost was € 1,570.95 per VAEs episode. The total direct additional cost for the two-year period was € 461,581.12.

Conclusions

These results confirm the importance of estimating VAEs real cost using micro-costing for analytical cost allocation, and MSM to avoid additional LOS and cost overestimation.

Early prediction of ventilator-associated pneumonia with machine learning models: A systematic review and meta-analysis of prediction model performance✰

BACKGROUND

Machine learning-based prediction models can catalog, classify, and correlate large amounts of multimodal data to aid clinicians at diagnostic, prognostic, and therapeutic levels. Early prediction of ventilator-associated pneumonia (VAP) may accelerate the diagnosis and guide preventive interventions. The performance of a variety of machine learning-based prediction models were analyzed among adults undergoing invasive mechanical ventilation.

METHODS

This systematic review and meta-analysis was conducted in accordance with the Cochrane Collaboration. Machine learning-based prediction models were identified from a search of nine multi-disciplinary databases. Two authors independently selected and extracted data using predefined criteria and data extraction forms. The predictive performance, the interpretability, the technological readiness level, and the risk of bias of the included studies were evaluated.

RESULTS

Final analysis included 10 static prediction models using supervised learning. The pooled area under the receiver operating characteristics curve, sensitivity, and specificity for VAP were 0.88 (95 % CI 0.82-0.94, I2 98.4 %), 0.72 (95 % CI 0.45-0.98, I2 97.4 %) and 0.90 (95 % CI 0.85-0.94, I2 97.9 %), respectively. All included studies had either a high or unclear risk of bias without significant improvements in applicability. The care-related risk factors for the best performing models were the duration of mechanical ventilation, the length of ICU stay, blood transfusion, nutrition strategy, and the presence of antibiotics.

CONCLUSION

A variety of the prediction models, prediction intervals, and prediction windows were identified to facilitate timely diagnosis. In addition, care-related risk factors susceptible for preventive interventions were identified. In future, there is a need for dynamic machine learning models using time-depended predictors in conjunction with feature importance of the models to predict real-time risk of VAP and related outcomes to optimize bundled care.

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.

Hospital-Acquired Pneumonia

Pneumonia acquired during hospitalization is called nosocomial pneumonia (NP). Nosocomial pneumonia is divided into two types. Hospital-acquired pneumonia (HAP) refers to hospital-acquired pneumonia, whereas ventilator-associated pneumonia (VAP) refers to ventilator-associated pneumonia. Most clinical literature stresses VAP’s importance and associated mortality and morbidity, whereas HAP is not given enough attention even while being the most common cause of NP. HAP, like VAP, carries a high mortality and morbidity. HAP is the commonest cause of mortality from hospital-acquired infections. HAP is a common determinant for intensive care unit (ICU) admits with respiratory failure. Recent research has identified definite risk factors responsible for HAP. If these are prevented or modified, the HAP incidence can be significantly decreased with improved clinical outcomes and lesser utilization of the health care resources. The prevention approach will need multiple strategies to address the issues. Precise epidemiological data on HAP is deficient due to limitations of the commonly used diagnostic measures. The diagnostic modalities available in HAP are less invasive than VAP. Recent infectious disease society guidelines have stressed the importance of HAP by removing healthcare-associated pneumonia as a diagnosis. Specific differences exist between HAP and VAP, which are gleaned over in this chapter.

An automated retrospective VAE-surveillance tool for future quality improvement studies

Ventilator-associated pneumonia (VAP) is a frequent complication of mechanical ventilation and is associated with substantial morbidity and mortality. Accurate diagnosis of VAP relies in part on subjective diagnostic criteria. Surveillance according to ventilator-associated event (VAE) criteria may allow quick and objective benchmarking. Our objective was to create an automated surveillance tool for VAE tiers I and II on a large data collection, evaluate its diagnostic accuracy and retrospectively determine the yearly baseline VAE incidence. We included all consecutive intensive care unit admissions of patients with mechanical ventilation at Bern University Hospital, a tertiary referral center, from January 2008 to July 2016. Data was automatically extracted from the patient data management system and automatically processed. We created and implemented an application able to automatically analyze respiratory and relevant medication data according to the Centers for Disease Control protocol for VAE-surveillance. In a subset of patients, we compared the accuracy of automated VAE surveillance according to CDC criteria to a gold standard (a composite of automated and manual evaluation with mediation for discrepancies) and evaluated the evolution of the baseline incidence. The study included 22'442 ventilated admissions with a total of 37'221 ventilator days. 592 ventilator-associated events (tier I) occurred; of these 194 (34%) were of potentially infectious origin (tier II). In our validation sample, automated surveillance had a sensitivity of 98% and specificity of 100% in detecting VAE compared to the gold standard. The yearly VAE incidence rate ranged from 10.1-22.1 per 1000 device days and trend showed a decrease in the yearly incidence rate ratio of 0.96 (95% CI, 0.93-1.00, p = 0.03). This study demonstrated that automated VAE detection is feasible, accurate and reliable and may be applied on a large, retrospective sample and provided insight into long-term institutional VAE incidences. The surveillance tool can be extended to other centres and provides VAE incidences for performing quality control and intervention studies.

Ventilator-Associated Events: Epidemiology, Risk Factors, and 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 in 2013 to increase the objectivity and reproducibility of surveillance and to encourage quality improvement programs to focus on preventing a broader array of complications. Ventilator-associated events are associated with a doubling of the risk of dying. Prospective studies have found that minimizing sedation, increasing spontaneous awakening and breathing trials, and conservative fluid management can decrease event rates and the duration of ventilation. Multifaceted interventions to enhance these practices can decrease ventilator-associated event rates.

Diagnostic and prognostic prediction models in ventilator-associated pneumonia: Systematic review and meta-analysis of prediction modelling studies

PURPOSE

Existing expert systems have not improved the diagnostic accuracy of ventilator-associated pneumonia (VAP). The aim of this systematic literature review was to review and summarize state-of-the-art prediction models detecting or predicting VAP from exhaled breath, patient reports and demographic and clinical characteristics.

METHODS

Both diagnostic and prognostic prediction models were searched from a representative list of multidisciplinary databases. An extensive list of validated search terms was added to the search to cover papers failing to mention predictive research in their title or abstract. Two authors independently selected studies, while three authors extracted data using predefined criteria and data extraction forms. The Prediction Model Risk of Bias Assessment Tool was used to assess both the risk of bias and the applicability of the prediction modelling studies. Technology readiness was also assessed.

RESULTS

Out of 2052 identified studies, 20 were included. Fourteen (70%) studies reported the predictive performance of diagnostic models to detect VAP from exhaled human breath with a high degree of sensitivity and a moderate specificity. In addition, the majority of them were validated on a realistic dataset. The rest of the studies reported the predictive performance of diagnostic and prognostic prediction models to detect VAP from unstructured narratives [2 (10%)] as well as baseline demographics and clinical characteristics [4 (20%)]. All studies, however, had either a high or unclear risk of bias without significant improvements in applicability.

CONCLUSIONS

The development and deployment of prediction modelling studies are limited in VAP and related outcomes. More computational, translational, and clinical research is needed to bring these tools from the bench to the bedside.

REGISTRATION

PROSPERO CRD42020180218, registered on 05-07-2020.

Subglottic suction frequency and adverse ventilator-associated events during critical illness

OBJECTIVE

Tracheal intubation and mechanical ventilation provide essential support for patients with respiratory failure, but the course of mechanical ventilation may be complicated by adverse ventilator-associated events (VAEs), which may or may not be associated with infection. We sought to understand how the frequency of subglottic suction, an indicator of the quantity of sputum produced by ventilated patients, relates to the onset of all VAEs and infection-associated VAEs.

DESIGN

We performed a case-crossover study including 87 patients with VAEs, and we evaluated 848 days in the pre-VAE period at risk for a VAE.

SETTING AND PARTICIPANTS

Critically ill patients were recruited from the medical intensive care unit of an academic medical center.

METHODS

We used the number of as-needed subglottic suctioning events performed per calendar day to quantify sputum production, and we compared the immediate pre-VAE period to the preceding period. We used CDC surveillance definitions for VAE and to categorize whether events were infection associated or not.

RESULTS

Sputum quantity measured by subglottic suction frequency is greater in the period immediately prior to VAE than in the preceding period. However, it does not discriminate well between infection-associated VAEs and VAEs without associated infection.

CONCLUSIONS

Subglottic suction frequency may serve as a valuable marker of sputum quantity, and it is associated with risk of a VAE. However, our results require validation in a broader population of mechanically ventilated patients and intensive care settings.

The Impact of a Multidisciplinary Education Program for Intensive Care Unit Staff Regarding Ventilator Care Bundle on the Frequency of Ventilator-Associated Events

BACKGROUND

Ventilator bundles have been reported to reduce the risk of ventilator-associated pneumonia. However, data concerning the role of the education of the intensive care unit (ICU) staff regarding the items in the bundle and the importance to adhere to its items on the development of ventilator-associated events (VAEs) are limited. This study aimed to compare the frequency of VAEs in subjects admitted to the ICU before and after the education of the ICU staff.

METHODS

A total of 105 subjects were enrolled in this retrospective study. The ICU staff, including the physicians, respiratory therapists, and nurses, received a 2-day educational lecture regarding items in the bundle as well as the need to adhere to its items. The study population was divided into two according to the admission date: subjects who were admitted before the education of the ICU staff regarding the ventilator bundle (preeducation) and subjects who were admitted after the education of the ICU staff regarding the ventilator bundle (posteducation). The difference in VAE rate in subjects admitted before and after bundle training was the primary outcome measure of this study.

RESULTS

The bundle compliance rates presented by days were significantly higher in the posteducation group compared with the preeducation group. Moreover, the frequency of VAEs was significantly lower in posteducation subjects compared with preeducation subjects (4.7% vs 19.0%, P = .042). Ventilator-associated event rate was also lower in posteducation subjects compared with preeducation subjects (2.5/1000 vs 9.8/1000 ventilator days). There were no significant differences among the groups with respect to ICU mortality.

CONCLUSION

The educational intervention performed in this study not only increased the adherence to the ventilator care bundle but also led to a significant reduction in the rate of the VAEs in patients receiving mechanical ventilator support in the ICU.

The epidemiology and clinical outcomes of ventilator-associated events among 20,769 mechanically ventilated patients at intensive care units: an observational study

Background

Ventilator-associated pneumonia (VAP) is the most common hospital-acquired infection (HAI) in intensive care units (ICUs). Ventilator-associated event (VAE), a more objective definition, has replaced traditional VAP surveillance and is now widely used in the USA. However, the adoption outside the USA is limited. This study aims to describe the epidemiology and clinical outcomes of VAEs in China, based on a prospectively maintained registry.

Methods

An observational study was conducted using an ICU-HAI registry in west China. Patients that were admitted to ICUs and underwent mechanical ventilation (MV) between April 1, 2015, and December 31, 2018, were included. The characteristics and outcomes were compared between patients with and without VAEs. The rates of all VAEs dependent on different ICUs were calculated, and the pathogen distribution of patients with possible VAP (PVAP) was described.

Results

A total of 20,769 ICU patients received MV, accounting for 21,723 episodes of mechanical ventilators and 112,697 ventilator-days. In all, we identified 1882 episodes of ventilator-associated condition (VAC) events (16.7 per 1000 ventilator-days), 721 episodes of infection-related ventilator-associated complications (IVAC) events (6.4 per 1000 ventilator-days), and 185 episodes of PVAP events (1.64 per 1000 ventilator-days). The rates of VAC varied across ICUs with the highest incidence in surgical ICUs (23.72 per 1000 ventilator-days). The median time from the start of ventilation to the onset of the first VAC, IVAC, and PVAP was 5 (3–8), 5 (3–9), and 6 (4–13) days, respectively. The median length of hospital stays was 28.00 (17.00–43.00), 30.00 (19.00–44.00), and 30.00 (21.00–46.00) days for the three VAE tiers, which were all longer than that of patients without VAEs (16.00 [12.00–23.00]). The hospital mortality among patients with VAEs was more than three times of those with non-VAEs.

Conclusions

VAE was common in ICU patients with ≥ 4 ventilator days. All tiers of VAEs were highly correlated with poor clinical outcomes, including longer ICU and hospital stays and increased risk of mortality. These findings highlight the importance of VAE surveillance and the development of new strategies to prevent VAEs.

Electronically assisted surveillance systems of healthcare-associated infections: a systematic review

Background

Surveillance of healthcare-associated infections (HAI) is the basis of each infection control programme and, in case of acute care hospitals, should ideally include all hospital wards, medical specialties as well as all types of HAI. Traditional surveillance is labour intensive and electronically assisted surveillance systems (EASS) hold the promise to increase efficiency.

Objectives

To give insight in the performance characteristics of different approaches to EASS and the quality of the studies designed to evaluate them.

Methods

In this systematic review, online databases were searched and studies that compared an EASS with a traditional surveillance method were included. Two different indicators were extracted from each study, one regarding the quality of design (including reporting efficiency) and one based on the performance (e.g. specificity and sensitivity) of the EASS presented.

Results

A total of 78 studies were included. The majority of EASS (n = 72) consisted of an algorithm-based selection step followed by confirmatory assessment. The algorithms used different sets of variables. Only a minority (n = 7) of EASS were hospital-wide and designed to detect all types of HAI. Sensitivity of EASS was generally high (> 0.8), but specificity varied (0.37–1). Less than 20% (n = 14) of the studies presented data on the efficiency gains achieved.

Conclusions

Electronically assisted surveillance of HAI has yet to reach a mature stage and to be used routinely in healthcare settings. We recommend that future studies on the development and implementation of EASS of HAI focus on thorough validation, reproducibility, standardised datasets and detailed information on efficiency.

A Comparison of Outcomes of Trauma Patients With Ventilator-Associated Events by Diagnostic Criteria Set

BACKGROUND

The Centers for Disease Control and Prevention replaced the definition for ventilator-associated pneumonia with an algorithm comprised of three categories: ventilator-associated condition (VAC), infection-related ventilator associated complication (IVAC), and possible ventilator-associated pneumonia (PVAP). We sought to compare the outcome of trauma patients with VAEs to those with no VAEs.

METHODS

Patients admitted from 2013 to 2017 were identified from trauma registry. Logistic regression was performed for the association between VAEs and mortality.

RESULTS

Two thousand six hundred eighty patients were admitted to our trauma center, 2,290 had no VAE, 100 had VACs, 85 had IVACs, and 205 had PVAPs. Adjusted for race, sex, blunt injury mechanisms, and Injury Severity Score, all VAEs had a longer hospital length of stay, intensive care unit stay, and days of ventilator support when compared with those with no VAE (all P < 0.0001). Nosocomial complication rates were not different by VAE group. Compared with patients with no VAE, an over 2-fold increased mortality odds was observed for VAC (OR 2.39, 95% CI 1.50-3.80) and IVAC patients (OR 2.07, 95% CI 1.23-3.47), and a 50% mortality increased was observed for PVAP patients (OR 1.46, 95% CI 1.00-2.12). These associations became similar with an approximate 2.5-fold increased mortality odds among patients with at least 1 week on ventilator support.

CONCLUSION

VAEs increase the odds of mortality, particularly for patients with VACs and IVACs. Among patients on ventilator support for at least a week, the associations are similar among VAE types, suggesting no single VAE type is more severe than others.

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.

The utility of endotracheal aspirate bacteriology in identifying mechanically ventilated patients at risk for ventilator associated pneumonia: a single-center prospective observational study

Background

Ventilator-associated pneumonia (VAP) is a well-known, life-threatening disease that persists despite preventative measures and approved antibiotic therapies. This prospective observational study investigated bacterial airway colonization, and whether its detection and quantification in the endotracheal aspirate (ETA) is useful for identifying mechanically ventilated ICU patients who are at risk of developing VAP.

Methods

240 patients admitted to 3 ICUs at the Lahey Hospital and Medical Center (Burlington, MA) between June 2014 and June 2015 and mechanically ventilated for > 2 days were included. ETA samples and clinical data were collected. Airway colonization was assessed, and subsequently categorized into “heavy” and “light” by semi-quantitative microbiological analysis of ETAs. VAP was diagnosed retrospectively by the study sponsor according to a pre-specified pneumonia definition.

Results

Pathogenic bacteria were isolated from ETAs of 125 patients. The most common species isolated was S. aureus (56.8%), followed by K. pneumoniae, P. aeruginosa, and E. coli (35.2% combined). VAP was diagnosed in 85 patients, 44 (51.7%) with no bacterial pathogen, 18 associated with S. aureus and 18 Gram-negative-only cases, and 5 associated with other Gram-positive or mixed species. A higher proportion of patients who were heavily colonized with S. aureus developed VAP (32.4%) associated with S. aureus compared to those lightly colonized (17.6%). The same tendency was seen for patients heavily and lightly colonized with Gram-negative pathogens (30.0 and 0.0%, respectively). Detection of S. aureus in the ETA preceded S. aureus VAP by approximately 4 days, while Gram-negative organisms were first detected 2.5 days prior to Gram-negative VAP. VAP was associated with significantly longer duration of mechanical ventilation and hospitalization regardless of microbiologic cause when compared to patients who did not develop VAP.

Conclusions

The overall VAP rate was 35%. Heavy tracheal colonization supported identification of patients at higher risk of developing a corresponding S. aureus or Gram-negative VAP. Detection of bacterial ETA-positivity tended to precede VAP.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4367-7) contains supplementary material, which is available to authorized users.

Ventilator-associated events in children: A review of literature

BACKGROUND

The complexity and variation in ventilator associated pneumonia (VAP) definitions in paediatrics may pose threats to the reliable identification of VAP. The revision of the surveillance definition to ventilator-associated event (VAE) has been mandated in adult populations, to overcome these issues. However, the evidence for application of the definition is unknown in children.

OBJECTIVES

To review the evidence on the application of the new VAE surveillance definition in paediatric population and examine the potential challenges in clinical practice.

REVIEW METHODS

A systematic approach was used to locate and synthesise the relevant paediatric literature. Studies were appraised according to epidemiological appraisal instrument (EAI) and the grades of evidence in the National Health Medical Research Council (NHMRC) guidelines.

RESULTS

Seven studies met the inclusion criteria. Quality of study methods was above 50% on the EAI. The overall grade of evidence was assessed as C (satisfactory). The incidence of VAE in children ranged from 1.1 to 20.9 per 1000 ventilator days as a result of variations in surveillance criteria across included studies. There is little agreement between the new VAE and PNU/VAP surveillance definition in the identification of VAP. Challenges in the application of VAE surveillance were related to; the difference in modes of ventilation used in children versus adults, inconclusive criteria tailored to paediatric samples and a lack of data that support for automatic data extraction applied in paediatric studies.

CONCLUSION

This review demonstrated promising evidence using the new VAE surveillance definition to define the VAE in children, but the level of the evidence is low. Before the possibility of real implementation in clinical settings, challenges related to VAE paediatric specific criteria' and the value of automated data collection need to be considered.

Pediatric Ventilator-Associated Events: Analysis of the Pediatric Ventilator-Associated Infection Data

OBJECTIVES

To compare the prevalence of infection applying the proposed pediatric ventilator-associated events criteria versus clinician-diagnosed ventilator-associated infection to subjects in the pediatric ventilator-associated infection study.

DESIGN

Analysis of prospectively collected data from the pediatric ventilator-associated infection study.

SETTING

PICUs of 47 hospitals in the United States, Canada, and Australia.

PATIENTS

Two-hundred twenty-nine children ventilated for greater than 48 hours who had respiratory secretion cultures performed to evaluate for suspected ventilator-associated infection.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Applying the proposed pediatric ventilator-associated event criteria, 15 of 229 subjects in the ventilator-associated infection study qualified as "ventilator-associated condition" and five of 229 (2%) met criteria for "infection-related ventilator-associated complication." This was compared with 89 of 229 (39%) diagnosed as clinical ventilator-associated infection (Kappa = 0.068). Ten of 15 subjects identified as ventilator-associated condition did not meet criteria for infection-related ventilator-associated complication primarily because they did not receive 4 days of antibiotics. Ventilator-associated condition subjects were similar demographically to nonventilator-associated condition subjects and had similar mortality (13% vs 10%), PICU-free days (6.9 ± 7.7; interquartile range, 0-14 vs 9.8 ± 9.6; interquartile range, 0-19; p = 0.25), but fewer ventilator-free days (6.6 ± 9.3; interquartile range, 1-15 vs 12.4 ± 10.7; interquartile range, 0-22; p = 0.04). The clinical ventilator-associated infection diagnosis in the ventilator-associated infection study was associated with fewer PICU-free days but no difference in mortality or ventilator-free days.

CONCLUSIONS

The ventilator-associated event criteria appear to be insensitive to the clinical diagnosis of ventilator-associated infection. Differentiation between ventilator-associated condition and infection-related ventilator-associated complication was primarily determined by the clinician decision to treat with antibiotics rather than clinical signs and symptoms. The utility of the proposed pediatric ventilator-associated event criteria as a surrogate for ventilator-associated infection criteria is unclear.

Ventilator-Associated Pneumonia and Events in Pediatric Intensive Care: A Single Center Study

OBJECTIVES

Ventilator-associated pneumonia is the second most common nosocomial infection in pediatric intensive care. The Centers for Disease Control and Prevention recently issued diagnosis criteria for pediatric ventilator-associated pneumonia and for ventilator-associated events in adults. The objectives of this pediatric study were to determine the prevalence of ventilator-associated pneumonia using these new Centers for Disease Control and Prevention criteria, to describe the risk factors and management of ventilator-associated pneumonia, and to assess a simpler method to detect ventilator-associated pneumonia with ventilator-associated event in critically ill children.

DESIGN

Retrospective, observational, single-center.

SETTING

PICU in a tertiary-care university hospital.

PATIENTS

Consecutive critically ill children mechanically ventilated for greater than or equal to 48 hours between November 2013 and November 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 304 patients mechanically ventilated for greater than or equal to 48 hours, 284 were included. Among them, 30 (10.6%) met clinical and radiologic Centers for Disease Control and Prevention criteria for ventilator-associated pneumonia, yielding an prevalence of 7/1,000 mechanical ventilation days. Median time from mechanical ventilation onset to ventilator-associated pneumonia diagnosis was 4 days. Semiquantitative culture of tracheal aspirates was the most common microbiological technique. Gram-negative bacteria were found in 60% of patients, with a predominance of Haemophilus influenzae and Pseudomonas aeruginosa. Antibiotic therapy complied with adult guidelines. Compared with patients without ventilator-associated pneumonia, those with ventilator-associated pneumonia had significantly longer median durations of mechanical ventilation (15 vs 6 d; p < 0.001) and PICU stay (19 vs 9 d; p < 0.001). By univariate analysis, risk factors for ventilator-associated pneumonia were younger age, reintubation, acute respiratory distress syndrome, and continuous enteral feeding. Among the 30 patients with ventilator-associated pneumonia, 17 met adult ventilator-associated event's criteria (sensitivity, 56%).

CONCLUSIONS

Ventilator-associated pneumonia is associated with longer times on mechanical ventilation and in the PICU. Using the ventilator-associated event criteria is of interest to rapidly screen for ventilator-associated pneumonia in children. However, sensitivity must be improved by adapting these criteria to children.

A Comparison of Clinical Characteristics and Outcomes of Ventilator-Associated Pneumonias Among Burn Patients by Diagnostic Criteria Set

OBJECTIVES

The National Healthcare Safety Network (NHSN) replaced its old definition for ventilator-associated pneumonia (VAP) with ventilator-associated events (VAEs) in 2013. Little data is available comparing the two definitions in burn patients.

METHODS

Data from 2011 to 2014 were collected on burn patients mechanically ventilated for at least 2 days. VAP was determined using two methods: (1) pneumonia as defined by the previous more clinical CDC (NHSN) definition captured in the burn registry; (2) pneumonia as defined by the recent CDC (NHSN) standard of VAEs where patients meeting the criteria for possible VAP were considered having a pneumonia. Cohen kappa statistic was measured to compare both definitions, and chi-square and ANOVA to compare admission and clinical outcomes.

RESULTS

There were 266 burn patients who were mechanically ventilated for at least 2 days between 2011 and 2014. One hundred patients (37.5%) met the criteria by the old definition and 35 (13.1%) met the criteria for both. The kappa statistic was 0.34 (95% confidence interval 0.23-0.45), suggesting weak agreement. Those who met both definitions were mechanically ventilated for a longer period of time (P = 0.0003), and had a longer intensive care unit (ICU) length of stay (LOS) (P = 0.0004) and hospital LOS (P = 0.0014).

CONCLUSIONS

There is weak agreement between the two definitions of VAP in severely burn patients. However, patients who met both VAP definitions had longer ventilator days, ICU, and hospital stays.

Prevalence of Dyspnea Among Hospitalized Patients at the Time of Admission

CONTEXT

Dyspnea is an uncomfortable and distressing sensation experienced by hospitalized patients.

OBJECTIVES

There is no large-scale study of the prevalence and intensity of patient-reported dyspnea at the time of admission to the hospital.

METHODS

Between March 2014 and September 2016, we conducted a prospective cohort study among all consecutive hospitalized patients at a single tertiary care center in Boston, MA. During the first 12 hours of admission to medical-surgical and obstetric units, nurses at our institution routinely collect a patient's 1) current level of dyspnea on a 0-10 scale with 10 anchored at "unbearable," 2) worst dyspnea in the past 24 hours before arrival at the hospital on the same 0-10 scale, and 3) activities that were associated with dyspnea before admission. The prevalence of dyspnea was identified, and tests of difference were performed across patient characteristics.

RESULTS

We analyzed 67,362 patients, 12% of whom were obstetric patients. Fifty percent of patients were admitted to a medical-surgical unit after treatment in the emergency department. Among all noncritically ill inpatients, 16% of patients experienced dyspnea in the 24 hours before the admission. Twenty-three percent of patients admitted through the emergency department reported any dyspnea in the past 24 hours. Eleven percent experienced some current dyspnea when interviewed within 12 hours of admission with 4% of patients experiencing dyspnea that was rated 4 or greater. Dyspnea of 4 or more was present in 43% of patients admitted with respiratory diagnoses and 25% of patients with cardiovascular diagnoses. After multivariable adjustment for severity of illness and patient comorbidities, patients admitted on the weekend or during the overnight nursing shift were more likely to report dyspnea on admission.

CONCLUSION

Dyspnea is a common symptom among all hospitalized patients. Routine documentation of dyspnea is feasible in a large tertiary care center.

Real-Time, Automated Detection of Ventilator-Associated Events: Avoiding Missed Detections, Misclassifications, and False Detections Due to Human Error

OBJECTIVETo validate a system to detect ventilator associated events (VAEs) autonomously and in real time.DESIGNRetrospective review of ventilated patients using a secure informatics platform to identify VAEs (ie, automated surveillance) compared to surveillance by infection control (IC) staff (ie, manual surveillance), including development and validation cohorts.SETTINGThe Massachusetts General Hospital, a tertiary-care academic health center, during January-March 2015 (development cohort) and January-March 2016 (validation cohort).PATIENTSVentilated patients in 4 intensive care units.METHODSThe automated process included (1) analysis of physiologic data to detect increases in positive end-expiratory pressure (PEEP) and fraction of inspired oxygen (FiO2); (2) querying the electronic health record (EHR) for leukopenia or leukocytosis and antibiotic initiation data; and (3) retrieval and interpretation of microbiology reports. The cohorts were evaluated as follows: (1) manual surveillance by IC staff with independent chart review; (2) automated surveillance detection of ventilator-associated condition (VAC), infection-related ventilator-associated complication (IVAC), and possible VAP (PVAP); (3) senior IC staff adjudicated manual surveillance-automated surveillance discordance. Outcomes included sensitivity, specificity, positive predictive value (PPV), and manual surveillance detection errors. Errors detected during the development cohort resulted in algorithm updates applied to the validation cohort.RESULTSIn the development cohort, there were 1,325 admissions, 479 ventilated patients, 2,539 ventilator days, and 47 VAEs. In the validation cohort, there were 1,234 admissions, 431 ventilated patients, 2,604 ventilator days, and 56 VAEs. With manual surveillance, in the development cohort, sensitivity was 40%, specificity was 98%, and PPV was 70%. In the validation cohort, sensitivity was 71%, specificity was 98%, and PPV was 87%. With automated surveillance, in the development cohort, sensitivity was 100%, specificity was 100%, and PPV was 100%. In the validation cohort, sensitivity was 85%, specificity was 99%, and PPV was 100%. Manual surveillance detection errors included missed detections, misclassifications, and false detections.CONCLUSIONSManual surveillance is vulnerable to human error. Automated surveillance is more accurate and more efficient for VAE surveillance.Infect Control Hosp Epidemiol 2018;826-833.

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.

Seeking out SARI: an automated search of electronic health records

The definition of severe acute respiratory infection (SARI) - a respiratory illness with fever and cough, occurring within the past 10 days and requiring hospital admission - has not been evaluated for critically ill patients. Using integrated electronic health records data, we developed an automated search algorithm to identify SARI cases in a large cohort of critical care patients and evaluate patient outcomes. We conducted a retrospective cohort study of all admissions to a medical intensive care unit from August 2009 through March 2016. Subsets were randomly selected for deriving and validating a search algorithm, which was compared with temporal trends in laboratory-confirmed influenza to ensure that SARI was correlated with influenza. The algorithm was applied to the cohort to identify clinical differences for patients with and without SARI. For identifying SARI, the algorithm (sensitivity, 86.9%; specificity, 95.6%) outperformed billing-based searching (sensitivity, 73.8%; specificity, 78.8%). Automated searching correlated with peaks in laboratory-confirmed influenza. Adjusted for severity of illness, SARI was associated with more hospital, intensive care unit and ventilator days but not with death or dismissal to home. The search algorithm accurately identified SARI for epidemiologic study and surveillance.

Resistance Trends and Treatment Options in Gram-Negative Ventilator-Associated Pneumonia

PURPOSE OF REVIEW

Hospital-acquired and ventilator-associated pneumonia (VAP) are frequent causes of infection among critically ill patients. VAP is the most common hospital-acquired bacterial infection among mechanically ventilated patients. Unfortunately, many of the nosocomial Gram-negative bacteria that cause VAP are increasingly difficult to treat. Additionally, the evolution and dissemination of multi- and pan-drug resistant strains leave clinicians with few treatment options. VAP patients represent a dynamic population at risk for antibiotic failure and under-dosing due to altered antibiotic pharmacokinetic parameters. Since few antibiotic agents have been approved within the last 15 years, and no new agents specifically targeting VAP have been approved to date, it is anticipated that this problem will worsen. Given the public health crisis posed by resistant Gram-negative bacteria, it is essential to establish a firm understanding of the current epidemiology of VAP, the changing trends in Gram-negative resistance in VAP, and the current issues in drug development for Gram-negative bacteria that cause VAP.

RECENT FINDINGS

Rapid identification technologies and phenotypic methods, new therapeutic strategies, and novel treatment paradigms have evolved in an attempt to improve treatment outcomes for VAP; however, clinical data supporting alternative treatment strategies and adjunctive therapies remain sparse. Importantly, new classes of antimicrobials, novel virulence factor inhibitors, and beta-lactam/beta-lactamase inhibitor combinations are currently in development. Conscientious stewardship of new and emerging therapeutic agents will be needed to ensure they remain effective well into the future.

Development and validation of an automated ventilator-associated event electronic surveillance system: A report of a successful implementation

BACKGROUND

Surveillance is an important tool for infection control; however, this task can often be time-consuming and take away from infection prevention activities. With the increasing availability of comprehensive electronic health records, there is an opportunity to automate these surveillance activities. The objective of this article is to describe the implementation of an electronic algorithm for ventilator-associated events (VAEs) at a large academic medical center METHODS: This article reports on a 6-month manual validation of a dashboard for VAEs. We developed a computerized algorithm for automatically detecting VAEs and compared the output of this algorithm to the traditional, manual method of VAE surveillance.

RESULTS

Manual surveillance by the infection preventionists identified 13 possible and 11 probable ventilator-associated pneumonias (VAPs), and the VAE dashboard identified 16 possible and 13 probable VAPs. The dashboard had 100% sensitivity and 100% accuracy when compared with manual surveillance for possible and probable VAP. We report on the successfully implemented VAE dashboard. Workflow of the infection preventionists was simplified after implementation of the dashboard with subjective time-savings reported.

CONCLUSIONS

Implementing a computerized dashboard for VAE surveillance at a medical center with a comprehensive electronic health record is feasible; however, this required significant initial and ongoing work on the part of data analysts and infection preventionists.

Burn patients with infection-related ventilator associated complications have worse outcomes compared to those without ventilator associated events

BACKGROUND

The Centers for Disease Control and Prevention (CDC) replaced its definition for ventilator-associated pneumonia (VAP) in 2013. The aim of the current study is to compare the outcome of burn patients with ventilator associated events (VAEs).

METHODS

Burn patients with at least two days of ventilator support were identified from the registry between 2013 and 2016. Kruskal-Wallis and Fisher's exact tests were utilized for continuous and categorical variables, respectively. A logistic regression was used for the association between VAE and in-hospital mortality.

RESULTS

243 patients were admitted to our burn center, of whom 208 had no VAE, 8 had a VAC, and 27 had an IVAC or PVAP. There was no difference in hospital length of stay, ICU length of stay and ventilator support days between those with no VAE and a VAC. Those with IVAC-plus had significantly worse outcomes compared to patients with no VAEs.

CONCLUSIONS

Burn patients with IVAC-plus had significantly longer hospital and ICU lengths of stay, days on ventilator compared with patients with no VAEs.

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.

What Is the Applicability of a Novel Surveillance Concept of Ventilator-Associated Events?

BACKGROUND

In 2013, the Centers for Disease Control and Prevention released a novel surveillance concept called the “ventilator-associated event,” which focused surveillance on objective measures of complications among patients that underwent invasive ventilations.

OBJECTIVE

To evaluate the concordance and possible differences in efficacy (ie, disease severity and outcomes) between 2 surveillance paradigms: (1) infection-related ventilator-associated complications (iVAC) and (2) on conventional ventilator-associated pneumonia (VAP).

DESIGN

Prospective, observational, single-center cohort study.

PATIENTS

This study included 85 adult patients that received invasive ventilation for at least 2 consecutive calendar days in a 22-bed, adult, mixed medical-surgical intensive care unit in Finland between October 2014 and June 2015.

RESULTS

Among these patients, 9 (10.1 per 1,000 days of mechanical ventilation) developed iVAC (10.6%) and 20 (22.4 per 1,000 days of mechanical ventilation) developed conventional VAP (23.5%). The iVAC indicators were most often caused by atelectasis and fluid overload. Compared with patients with conventional VAP, patients with iVAC had significantly worse respiratory status but no other differences in disease severity or outcomes.

CONCLUSIONS

The incidence of conventional VAP was >2-fold that of iVAC, and the surveillance paradigms for VAP and iVAC capture different patterns of disease. Our results suggest that this novel surveillance concept, although based on objective measures of declining oxygenation, actually identified deteriorations of oxygenation due to noninfectious causes.

Infect Control Hosp Epidemiol 2017;38:983–988

Incidence and Characteristics of Ventilator-Associated Events Reported to the National Healthcare Safety Network in 2014

Supplemental Digital Content is available in the text.

Objective:

Ventilator-associated event surveillance was introduced in the National Healthcare Safety Network in 2013, replacing surveillance for ventilator-associated pneumonia in adult inpatient locations. We determined incidence rates and characteristics of ventilator-associated events reported to the National Healthcare Safety Network.

Design, Setting, and Patients:

We analyzed data reported from U.S. healthcare facilities for ventilator-associated events that occurred in 2014, the first year during which ventilator-associated event surveillance definitions were stable. We used negative binomial regression modeling to identify healthcare facility and inpatient location characteristics associated with ventilator-associated events. We calculated ventilator-associated event incidence rates, rate distributions, and ventilator utilization ratios in critical care and noncritical care locations and described event characteristics.

Measurements and Main Results:

A total of 1,824 healthcare facilities reported 32,772 location months of ventilator-associated event surveillance data to the National Healthcare Safety Network in 2014. Critical care unit pooled mean ventilator-associated event incidence rates ranged from 2.00 to 11.79 per 1,000 ventilator days, whereas noncritical care unit rates ranged from 0 to 14.86 per 1,000 ventilator days. The pooled mean proportion of ventilator-associated events defined as infection-related varied from 15.38% to 47.62% in critical care units. Pooled mean ventilator utilization ratios in critical care units ranged from 0.24 to 0.47.

Conclusions:

We found substantial variability in ventilator-associated event incidence, proportions of ventilator-associated events characterized as infection-related, and ventilator utilization within and among location types. More work is needed to understand the preventable fraction of ventilator-associated events and identify patient care strategies that reduce ventilator-associated events.

Trauma patients meeting both Centers for Disease Control and Prevention's definitions for ventilator-associated pneumonia had worse outcomes than those meeting only one

BACKGROUND

The Centers for Disease Control and Prevention's National Healthcare Safety Network (NHSN) replaced its old definition for ventilator-associated pneumonia (VAP) with the ventilator-associated events algorithm in 2013. We sought to compare the outcome of trauma patients meeting the definitions for VAP in the two modules.

METHODS

Trauma patients with blunt or penetrating injuries and with at least 2 d of ventilator support were identified from the trauma registry from 2013 to 2014. VAP was determined using two methods: (1) VAP as defined by the "old," clinically based NHSN definition and (2) possible VAP as defined by the updated "new" NHSN definition. Cohen's kappa statistic was determined to compare the two definitions for VAP. To compare demographic and clinical outcomes, the chi-square and Student's t-tests were used for categorical and continuous variables, respectively.

RESULTS

From 2013 to 2014, there were 1165 trauma patients admitted who had at least 2 d of ventilator support. Seventy-eight patients (6.6%) met the "new" NHSN definition for possible VAP, 361 patients (30.9%) met the "old" definition of VAP, and 68 patients (5.8%) met both definitions. The kappa statistic between VAP as defined by the "new" and "old" definitions was 0.22 (95% confidence interval, 0.17-0.27). There were no differences in age, gender, race, or injury severity score when comparing patients who met the different definitions. Those satisfying both definitions had longer ventilator support days (P = 0.0009), intensive care unit length of stay (LOS; P = 0.0003), and hospital LOS (P = 0.0344) when compared with those meeting only one definition. There was no difference in mortality for those meeting both and those meeting the old definition for VAP; patients meeting both definitions had higher respiratory rate at arrival (P = 0.0178).

CONCLUSIONS

There was no difference in mortality between patients meeting the "old" and "new" NHSN definitions for VAP; those who met "both" definitions had longer ventilator support days, intensive care unit, and hospital LOS.

Ventilator-Associated Pneumonia: New Definitions

The National Healthcare Safety Network's new classification characterizes all adverse ventilator-associated events (VAE) into a tiered system designed to shift the focus away from ventilator-associated pneumonia as the only important cause or morbidity in ventilated patients. This new surveillance definition of VAE eliminates subjectivity by using clearly defined criteria and facilitates the automated collection of data. This allows for easier comparison and analysis of factors affecting rates of VAE. Numerous studies have been published that demonstrate its clinical application. This article presents the VAE criteria, contrasts the difference from the previous ventilator-associated pneumonia definition, and discusses its implementation over the past 5 years.

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.

A Pediatric Approach to Ventilator-Associated Events Surveillance

OBJECTIVE Adult ventilator-associated event (VAE) definitions include ventilator-associated conditions (VAC) and subcategories for infection-related ventilator-associated complications (IVAC) and possible ventilator-associated pneumonia (PVAP). We explored these definitions for children. DESIGN Retrospective cohort SETTING Pediatric, cardiac, or neonatal intensive care units (ICUs) in 6 US hospitals PATIENTS Patients ≤18 years old ventilated for ≥1 day METHODS We identified patients with pediatric VAC based on previously proposed criteria. We applied adult temperature, white blood cell count, antibiotic, and culture criteria for IVAC and PVAP to these patients. We matched pediatric VAC patients with controls and evaluated associations with adverse outcomes using Cox proportional hazards models. RESULTS In total, 233 pediatric VACs (12,167 ventilation episodes) were identified. In the cardiac ICU (CICU), 62.5% of VACs met adult IVAC criteria; in the pediatric ICU (PICU), 54.2% of VACs met adult IVAC criteria; and in the neonatal ICU (NICU), 20.2% of VACs met adult IVAC criteria. Most patients had abnormal white blood cell counts and temperatures; we therefore recommend simplifying surveillance by focusing on "pediatric VAC with antimicrobial use" (pediatric AVAC). Pediatric AVAC with a positive respiratory diagnostic test ("pediatric PVAP") occurred in 8.9% of VACs in the CICU, 13.3% of VACs in the PICU, and 4.3% of VACs in the NICU. Hospital mortality was increased, and hospital and ICU length of stay and duration of ventilation were prolonged among all pediatric VAE subsets compared with controls. CONCLUSIONS We propose pediatric AVAC for surveillance related to antimicrobial use, with pediatric PVAP as a subset of AVAC. Studies on generalizability and responsiveness of these metrics to quality improvement initiatives are needed, as are studies to determine whether lower pediatric VAE rates are associated with improvements in other outcomes. Infect Control Hosp Epidemiol 2017;38:327-333.

Does ventilator-associated event surveillance detect ventilator-associated pneumonia in intensive care units? A systematic review and meta-analysis

Background

Ventilator-associated event (VAE) is a new surveillance paradigm for monitoring complications in mechanically ventilated patients in intensive care units (ICUs). The National Healthcare Safety Network replaced traditional ventilator-associated pneumonia (VAP) surveillance with VAE surveillance in 2013. The objective of this study was to assess the consistency between VAE surveillance and traditional VAP surveillance.

Methods

We systematically searched electronic reference databases for articles describing VAE and VAP in ICUs. Pooled VAE prevalence, pooled estimates (sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV)) of VAE for the detection of VAP, and pooled estimates (weighted mean difference (WMD) and odds ratio ([OR)) of risk factors for VAE compared to VAP were calculated.

Results

From 2191 screened titles, 18 articles met our inclusion criteria, representing 61,489 patients receiving mechanical ventilation at ICUs in eight countries. The pooled prevalence rates of ventilator-associated conditions (VAC), infection-related VAC (IVAC), possible VAP, probable VAP, and traditional VAP were 13.8 %, 6.4 %, 1.1 %, 0.9 %, and 11.9 %, respectively. Pooled sensitivity and PPV of each VAE type for VAP detection did not exceed 50 %, while pooled specificity and NPV exceeded 80 %. Compared with VAP, pooled ORs of in-hospital death were 1.49 for VAC and 1.76 for IVAC; pooled WMDs of hospital length of stay were −4.27 days for VAC and −5.86 days for IVAC; and pooled WMDs of ventilation duration were −2.79 days for VAC and −2.89 days for IVAC.

Conclusions

VAE surveillance missed many cases of VAP, and the population characteristics identified by the two surveillance paradigms differed. VAE surveillance does not accurately detect cases of traditional VAP in ICUs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1506-z) contains supplementary material, which is available to authorized users.

Evaluation of the New Centers for Disease Control and Prevention Ventilator-Associated Event Module and Criteria in Critically Ill Children in Greece

OBJECTIVE To evaluate the new adult Centers for Disease Control and Prevention (CDC) ventilator-associated event (VAE) module in critically ill children and compare with the traditionally used CDC definition for ventilator-associated pneumonia (VAP). DESIGN Retrospective observational study of mechanically ventilated children in a pediatric intensive care unit in Greece January 1-December 31, 2011. METHODS Assessment of new adult CDC VAE module including 3 definition tiers: ventilator-associated condition (VAC), infection-related VAC, and possible/probable ventilator-associated pneumonia (VAE-VAP); comparison with traditional CDC criteria for clinically defined pneumonia in mechanically ventilated children (PNEU-VAP). We recorded Pediatric Risk of Mortality score at admission (PRISM III), number of ventilator-days, and outcome. RESULTS Among 119 patients with mechanical ventilation (median [range] number of ventilator-days, 7 [1-183]), 19 patients experienced VAC. Criteria for VAE-VAP were fulfilled in 12 of 19 patients with VAC (63%). Children with either VAC or VAE-VAP were on ventilation more days than patients without these conditions (16.5 vs 5 d, P=.0006 and 18 vs 5 d, P<.001, respectively), whereas PRISM-III score was similar between them. Mortality was significant higher in patients with new VAE-VAP definition (50%), but not in patients with VAC (31.6%), than the patients without new VAE-VAP (14%, P=.007) or VAC (15%, P=.1), respectively. No significant association was found between PNEU-VAP and death. Incidences of PNEU-VAP and VAE-VAP were similar, but the agreement was poor. CONCLUSIONS VAE-VAP and PNEU-VAP found similar prevalence in critically ill children but with poor agreement. However, excess of death was significantly associated only with VAE-VAP. Infect Control Hosp Epidemiol 2016:1-5.

Complications and Resource Utilization Associated With Mechanical Ventilation in a Medical Intensive Care Unit in 2013

INTRODUCTION

Evolving strategies for ventilator management could reduce the frequency of complications, but there is limited information about complications in contemporary intensive care units.

METHODS

We retrospectively collected information about patient demographics, chest x-ray abnormalities, complications, including pneumothoraces, ventilator-associated events, self-extubation, and resource utilization in 174 patients who required mechanical ventilation in 2013.

RESULTS

The mean age was 57.8 ± 16.8 years, the number of ventilator days was 7.5 ± 7, and the overall in-hospital mortality was 32.2%. The mean fluid balance per day during the mechanical ventilation period was 1539 ± 1721 mL. Three (1.7%) patients developed pneumothoraces, and 5 patients required chest tubes. Twenty-five (14.4%) patients had ventilator-associated events. Ten patients had episodes of self-extubation, and 11 had episodes of failed extubation. Chest X-rays showed new or increasing infiltrates in 113 (64.9%) patients and new or increasing pleural effusions in 29 (16.7%) patients. These patients had 1.2 ± 0.4 X-rays per day on the ventilator, and they had 10.0 ± 9.4 arterial blood gases and 0.7 ± 0.7 central lines.

CONCLUSION

The frequency of ventilator-associated complications was low in this study. However, these patients frequently developed increasing infiltrates, and these outcomes need attention during patient management and are a potential focus for future studies.

Potential Strategies to Prevent Ventilator-associated Events

The Centers for Disease Control and Prevention (CDC) released ventilator-associated event (VAE) definitions in 2013. The new definitions were designed to track episodes of sustained respiratory deterioration in mechanically ventilated patients after a period of stability or improvement. More than 2,000 U.S. hospitals have reported their VAE rates to the CDC, but there has been little guidance to date on how to prevent VAEs. Existing ventilator-associated pneumonia prevention bundles are unlikely to be optimal insofar as pneumonia accounts for only a minority of VAEs. This review proposes a framework and potential intervention set to prevent VAEs on the basis of studies of VAE epidemiology, risk factors, and prevention. Work to date suggests that the majority of VAEs are caused by four conditions: pneumonia, fluid overload, atelectasis, and acute respiratory distress syndrome. Interventions that minimize ventilator exposure and target one or more of these conditions may therefore prevent VAEs. Potential strategies include avoiding intubation, minimizing sedation, paired daily spontaneous awakening and breathing trials, early exercise and mobility, low tidal volume ventilation, conservative fluid management, and conservative blood transfusion thresholds. Interventional studies have thus far affirmed that minimized sedation, paired daily spontaneous awakening and breathing trials, and conservative fluid management can reduce VAE rates and improve patient-centered outcomes. Further studies are needed to evaluate the impact of the other proposed interventions, to identify additional modifiable risk factors for VAEs, and to measure whether combining strategies into VAE prevention bundles confers additional benefits over implementing one or more of these interventions in isolation.

Association of Patient Care with Ventilator-Associated Conditions in Critically Ill Patients: Risk Factor Analysis

Background

Ventilator-associated conditions (VACs), for which new surveillance definitions and methods were issued by the Center for Disease Control and Prevention (CDC), are respiratory complications occurring in conjunction with the use of invasive mechanical ventilation and are related to adverse outcomes in critically ill patients. However, to date, risk factors for VACs have not been adequately established, leading to a need for developing a better understanding of the risks. The objective of this study was to explore care-related risk factors as a process indicator and provide valuable information pertaining to VAC preventive measures.

Methods

This retrospective, single-center, cohort study was conducted in the intensive-care unit (ICU) of a university hospital in Japan. Patient data were automatically sampled using a computerized medical records system and retrospectively analyzed. Management and care-related, but not host-related, factors were exhaustively analyzed using multivariate analysis for risks of VACs. VAC correlation to mortality was also investigated.

Results

Of the 3122 patients admitted in the ICU, 303 ventilated patients meeting CDC-specified eligibility criteria were included in the analysis. Thirty-seven VACs (12.2%) were found with a corresponding rate of 12.1 per 1000 ventilator days. Multivariate analysis revealed four variables related to patient care as risk factors for VACs: absence of intensivist participation in management of ventilated patients [adjusted HR (AHR): 7.325, P < 0.001)], using relatively higher driving pressure (AHR: 1.216, P < 0.001), development of edema (AHR: 2.145, P = 0.037), and a larger body weight increase (AHR: 0.058, P = 0.005). Furthermore, this research confirmed mortality differences in patients with VACs and statistically derived risks compared with those without VACs (HR: 2.623, P = 0.008).

Conclusion

Four risk factors related to patient care were clearly identified to be the key factors for VAC preventive measures.

Frequency and Etiology of Ventilator-Associated Events in the Medical Intensive Care Unit

BACKGROUND

The Centers for Disease Control and Prevention (CDC) has developed new criteria based on a significant deterioration in oxygenation to identify ventilator-associated events (conditions). The aim of this study was to determine how frequently this happened and what caused these conditions.

METHODS

Electronic medical records and x-rays from 281 ventilator episodes in the medical intensive care unit were reviewed to determine the characteristics of patients requiring ventilation and the number of patients meeting the criteria for ventilator-associated conditions (VACs).

RESULTS

This cohort included 257 patients (55.4% men) who required 281 episodes of mechanical ventilation. The mean Acute Physiology and Chronic Healthy Evaluation II score was 13.5 ± 5.9. The initial mean PaO2/FiO2 was 210 ± 110. The median number of ventilator days was 4 (interquartile range: 3-9). The overall mortality was 32.3%. Nineteen patients (11.7% of eligible episodes) met the CDC criteria for a VAC; 6 met FiO2 criteria (31.6%) and 13 met positive end expiratory pressure criteria (68.4%). Twelve patients (63.2%) had an increased white blood cell count (>12k/μL) during the event. Eleven patients had an increase in temperature (>38°C) during this period. The etiology of these conditions included pneumonia (n = 4), atelectasis (n = 4), congestive heart failure (n = 5), acute respiratory distress syndrome (n = 2), and miscellaneous reasons (n = 4).

CONCLUSIONS

VACs occurred in 11.7% of patients in our medical intensive care unit. The etiology of these events was diverse and did not usually reflect complications. These new CDC criteria for institutional reporting of complications during mechanical ventilation do not necessarily identify complications or provide a good method for comparing outcomes in hospitals.

Ventilator-associated conditions versus ventilator-associated pneumonia: different by design

The Centers for Disease Control and Prevention (CDC) released a new surveillance concept called ventilator-associated conditions (VACs) in early 2013. VAC was created to overcome some of the limitations of traditional ventilator-associated pneumonia (VAP) definitions, including their complexity, subjectivity, and insensitivity to complications other than pneumonia. VAC is defined by sustained increases in ventilator support after ≥2 days of stable or decreasing settings. The VAC definition was designed to be objective, reproducible, and amenable to automated analysis. Moreover, VAC purposefully broadens the scope of surveillance to include physiologically significant complications of care in addition to pneumonia, most commonly pulmonary edema, atelectasis, and acute respiratory distress syndrome. VAC definitions offer an opportunity for hospital quality improvement programs to get a fuller picture of the breadth and burden of complications in their critically ill populations and to use these data to catalyze enhanced prevention and control programs to better prevent these conditions.