Interrater Reliability of Surveillance for Ventilator-Associated Events and Pneumonia

Electronic surveillance criteria for non-ventilator-associated hospital-acquired pneumonia: Assessment of reliability and validity

OBJECTIVE

Surveillance of non-ventilator-associated hospital-acquired pneumonia (NV-HAP) is complicated by subjectivity and variability in diagnosing pneumonia. We compared a fully automatable surveillance definition using routine electronic health record data to manual determinations of NV-HAP according to surveillance criteria and clinical diagnoses.

METHODS

We retrospectively applied an electronic surveillance definition for NV-HAP to all adults admitted to Veterans' Affairs (VA) hospitals from January 1, 2015, to November 30, 2020. We randomly selected 250 hospitalizations meeting NV-HAP surveillance criteria for independent review by 2 clinicians and calculated the percent of hospitalizations with (1) clinical deterioration, (2) CDC National Healthcare Safety Network (CDC-NHSN) criteria, (3) NV-HAP according to a reviewer, (4) NV-HAP according to a treating clinician, (5) pneumonia diagnosis in discharge summary; and (6) discharge diagnosis codes for HAP. We assessed interrater reliability by calculating simple agreement and the Cohen κ (kappa).

RESULTS

Among 3.1 million hospitalizations, 14,023 met NV-HAP electronic surveillance criteria. Among reviewed cases, 98% had a confirmed clinical deterioration; 67% met CDC-NHSN criteria; 71% had NV-HAP according to a reviewer; 60% had NV-HAP according to a treating clinician; 49% had a discharge summary diagnosis of pneumonia; and 82% had NV-HAP according to any definition according to at least 1 reviewer. Only 8% had diagnosis codes for HAP. Interrater agreement was 75% (κ = 0.50) for CDC-NHSN criteria and 78% (κ = 0.55) for reviewer diagnosis of NV-HAP.

CONCLUSIONS

Electronic NV-HAP surveillance criteria correlated moderately with existing manual surveillance criteria. Reviewer variability for all manual assessments was high. Electronic surveillance using clinical data may therefore allow for more consistent and efficient surveillance with similar accuracy compared to manual assessments or diagnosis codes.

Changes in the epidemiology of ventilator-associated events over the course of the coronavirus disease 2019 (COVID-19) pandemic

Management of critically ill coronavirus disease 2019 (COVID-19) patients has evolved considerably during the pandemic. We investigated rates and causes of ventilator-associated events (VAEs) in COVID-19 patients in the late versus early waves in 4 Massachusetts hospitals. VAE rates per episode decreased, rates per ventilator day were stable, and most cases were caused by acute respiratory distress syndrome (ARDS).

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.

Prevalence, Clinical Characteristics, and Outcomes of Sepsis Caused by Severe Acute Respiratory Syndrome Coronavirus 2 Versus Other Pathogens in Hospitalized Patients With COVID-19

The prevalence and causes of sepsis in patients hospitalized with COVID-19 are poorly characterized.

OBJECTIVES

To investigate the prevalence, clinical characteristics, and outcomes of sepsis caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) versus other pathogens in patients hospitalized with COVID-19.

DESIGN SETTING AND PARTICIPANTS

Cross-sectional, retrospective chart review of 200 randomly selected patients hospitalized with COVID-19 at four Massachusetts hospitals between March 2020 and March 2021.

MAIN OUTCOMES AND MEASURES

The presence or absence of sepsis was determined per Sepsis-3 criteria (infection leading to an increase in Sequential Organ Failure Assessment score by ≥ 2 points above baseline). Sepsis episodes were assessed as caused by SARS-CoV-2, other pathogens, or both. Rates of organ dysfunction and in-hospital death were also assessed.

RESULTS

Sepsis was present in 65 of 200 COVID-19 hospitalizations (32.5%), of which 46 of 65 sepsis episodes (70.8%) were due to SARS-CoV-2 alone, 17 of 65 (26.2%) were due to both SARS-CoV-2 and non-SARS-CoV-2 infections, and two of 65 (3.1%) were due to bacterial infection alone. SARS-CoV-2-related organ dysfunction in patients with sepsis occurred a median of 1 day after admission (interquartile range, 0-2 d) and most often presented as respiratory (93.7%), neurologic (46.0%), and/or renal (39.7%) dysfunctions. In-hospital death occurred in 28 of 200 COVID-19 hospitalizations (14.0%), including two of 135 patients without sepsis (1.5%), 16 of 46 patients with sepsis (34.8%) due to SARS-CoV-2 alone, and 10 of 17 patients with sepsis (58.8%) due to both SARS-CoV-2 and bacterial pathogens.

CONCLUSIONS

Sepsis occurred in one in three patients hospitalized with COVID-19 and was primarily caused by SARS-CoV-2 itself, although bacterial infection also contributed in a quarter of sepsis cases. Mortality in COVID-19 patients with sepsis was high, especially in patients with mixed SARS-CoV-2 and bacterial sepsis. These findings affirm SARS-CoV-2 as an important cause of sepsis and highlight the need to improve surveillance, recognition, prevention, and treatment of both viral and bacterial sepsis in hospitalized patients with COVID-19.

Incidence, Characteristics, and Outcomes of Ventilator-associated Events during the COVID-19 Pandemic

Rationale: Ventilator-associated event (VAE) surveillance provides an objective means to measure and compare complications that develop during mechanical ventilation by identifying patients with sustained increases in ventilator settings after a period of stable or decreasing ventilator settings. The impact of the coronavirus disease (COVID-19) pandemic on VAE rates and characteristics is unknown. Objectives: To compare the incidence, causes, and outcomes of VAE during the COVID-19 pandemic year versus prepandemic years and among ventilated patients with and without COVID-19. Methods: In this retrospective cohort study of mechanically ventilated adults at four academic and community hospitals in Massachusetts, we compared VAE incidence rates between March 1 and August 31 for each year from 2017 to 2020 (corresponding to the time frame of the pandemic first wave in 2020) and among COVID-19-positive and COVID-19-negative patients in 2020. The medical records of 200 randomly selected patients with VAEs in 2020 (100 with COVID-19 and 100 without COVID-19) were analyzed to compare conditions precipitating VAEs in patients with versus without COVID-19. Results: VAEs per 100 episodes of mechanical ventilation were more common in 2020 than in prior years (11.2 vs. 6.7; P < 0.01) but the rate of VAEs per 1,000 ventilator-days was similar (14.2 vs. 12.7; P = 0.08). VAEs were more frequent in COVID-19-positive patients than in COVID-19-negative patients in 2020 (29.0 vs. 7.1 per 100 ventilator episodes [P < 0.01] and 17.2 vs. 12.2 per 1,000 ventilator-days [P < 0.01]). Compared with patients without COVID-19 with VAEs, patients with COVID-19 and VAEs had similar rates of infection-related ventilator-associated complications, longer median durations of mechanical ventilation (22 vs. 14 d; P < 0.01), and similar in-hospital mortality (30% vs. 38%; P = 0.15). Progressive acute respiratory distress syndrome (ARDS) accounted for 53% of VAEs in patients with COVID-19, whereas it accounted for 14% of VAEs among patients without COVID-19. Conclusions: VAE rates per 100 episodes of mechanical ventilation and per 1,000 ventilator-days were higher among COVID-19-positive patients than among COVID-19-negative patients. Over 50% of VAEs in patients with COVID-19 were caused by progressive ARDS, whereas less than 15% of VAEs in patients without COVID-19 were caused by progressive ARDS. These findings provide insight into the natural history of COVID-19 in ventilated patients and may inform targeted strategies to mitigate complications in this population.

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.

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.

Accuracy and reliability of electronic versus CDC surveillance criteria for non-ventilator hospital-acquired pneumonia

Nonventilator hospital-acquired pneumonia (NV-HAP) is one of the most common healthcare-associated infections, but most hospitals do not track it. We created a pilot electronic definition for NV-HAP and compared its accuracy to Centers for Disease Control and Prevention (CDC) criteria. Kappa values for the electronic definition and CDC criteria versus "true" pneumonia were similar: 0.40 and 0.47, respectively.

Development and Assessment of Objective Surveillance Definitions for Nonventilator Hospital-Acquired Pneumonia

IMPORTANCE

Hospital-acquired pneumonia is the most common health care-associated infection in the United States. Most cases occur in nonventilated patients, but many hospitals track hospital-acquired pneumonia only in ventilated patients because of the complexity and subjectivity of conducting surveillance for large numbers of nonventilated patients.

OBJECTIVE

To propose and assess potentially objective, efficient, and reproducible surveillance definitions for nonventilator hospital-acquired pneumonia (NV-HAP) using routine clinical data stored in electronic health record systems.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted in 2 tertiary referral and 2 community hospitals in Massachusetts between May 31, 2015, and July 1, 2018. All nonventilated patients aged 18 years or older who were admitted to these hospitals were included (N = 310 651).

EXPOSURES

Ten candidate definitions for NV-HAP based on clinically meaningful combinations of 6 potential surveillance criteria were proposed: worsening oxygenation, temperature higher than 38 °C (fever), abnormal white blood cell count of less than 4000/μL or more than 12 000/μL, performance of chest imaging, submission of respiratory specimen for culture, and 3 or more days of new antibiotics.

MAIN OUTCOMES AND MEASURES

Incidence rates, lengths of stay, hospital mortality rates, and odds ratios (ORs) for time to discharge and mortality compared with those of matched controls were calculated for each candidate definition. The ORs were adjusted for demographics, clinical service, comorbidities, and severity of illness.

RESULTS

The study analyzed 310 651 patients with 489 519 admissions, including 205 054 patients with 311 484 admissions of 3 or more days. Among the patients with 311 484 admissions, the mean (SD) patient age was 58.3 (19.3) years and 176 936 (56.8%) were of women. Incidence rates for candidate definitions per 100 admissions ranged from 3.4 events for worsening oxygenation alone to 0.9 event for worsening oxygenation and at least 3 days of new antibiotics to 0.6 event for worsening oxygenation, at least 3 days of new antibiotics, fever, abnormal white blood cell count, and performance of chest imaging. Crude mortality rates ranged from 16.1% (n = 2643) for patients with worsening oxygen alone to 27.7% (n = 868) for patients with worsening oxygenation, at least 3 days of antibiotics, fever or abnormal white blood cell count, and chest imaging. Patients who met NV-HAP candidate definitions remained in the hospital for twice as long as their matched controls (adjusted ORs ranged from 1.8 [95% CI, 1.7-1.8] to 2.1 [95% CI, 2.0-2.1]) and were 4 to 6 times as likely to die in the hospital (adjusted ORs ranged from 3.8 [95% CI, 3.5-4.0] to 6.5 [95% CI, 5.2-8.2]). Agreement between candidate definitions and clinical diagnoses was fair (κ = 0.33).

CONCLUSIONS AND RELEVANCE

These findings suggest that objective surveillance for NV-HAP using electronically computable definitions that incorporate common clinical criteria is feasible and generates incidence, mortality, and adjusted ORs for hospital mortality similar to estimates from manual surveillance. These definitions have the potential to facilitate widespread, automated surveillance for NV-HAP and thus inform the development and evaluation of prevention programs.

Using flexible methods to determine risk factors for ventilator-associated pneumonia in the Netherlands

Seven hospitals participated in the Dutch national surveillance for ventilator-associated pneumonia (VAP) and its risk factors. We analysed time-independent and time-dependent risk factors for VAP using the standard Cox regression and the flexible Weighted Cumulative Effects method (WCE) that evaluates both current and past exposures. The prospective surveillance of intensive care patients aged ≥16 years and ventilated ≥48 hours resulted in the inclusion of 940 primary ventilation periods, comprising 7872 ventilation days. The average VAP incidence density was 10.3/1000 ventilation days. Independent risk factors were age (16–40 years at increased risk: HR 2.42 95% confidence interval 1.07–5.50), COPD (HR 0.19 [0.04–0.78]), current sedation score (higher scores at increased risk), current selective oropharyngeal decontamination (HR 0.19 [0.04–0.91]), jet nebulizer (WCE, decreased risk), intravenous antibiotics for selective decontamination of the digestive tract (ivSDD, WCE, decreased risk), and intravenous antibiotics not for SDD (WCE, decreased risk). The protective effect of ivSDD was afforded for 24 days with a delay of 3 days. For some time-dependent variables, the WCE model was preferable over standard Cox proportional hazard regression. The WCE method can furthermore increase insight into the active time frame and possible delay herein of a time-dependent risk factor.

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

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

Hospital-Acquired Infections in Critically Ill Patients With Cancer

Hospital-acquired infections are a common and costly problem facing critically ill patients in the intensive care unit (ICU). Critically ill patients with cancer are a particularly vulnerable subpopulation who possesses additional, nonmodifiable risk factors for developing these infections and, in many cases, are at increased risk of death as a result. This review will describe the most common nosocomial infections patients with cancer acquire while in the ICU: ventilator-associated events, central line-associated bloodstream infection, catheter-associated urinary tract infections, and Clostridium difficile infection.

Assessing predictive accuracy for outcomes of ventilator-associated events in an international cohort: the EUVAE study

Purpose

To analyze the impact on patient outcome of ventilator-associated events (VAEs) as defined by the Centers for Disease Control and Prevention (CDC) in 2008, 2013, and the correlation with ventilator-associated pneumonia (VAP) or tracheobronchitis (VAT).

Methods

This was a prospective, observational, multicenter, international study conducted at 13 intensive care units (ICUs); thirty consecutive adults mechanically ventilated for ≥ 48 h per site were eligible, with daily follow-up being recorded in a collaborative web database; VAEs were assessed using the 2013 CDC classification and its 2015 update.

Results

A total of 2856 ventilator days in 244 patients were analyzed, identifying 33 VAP and 51 VAT episodes; 30-day ICU mortality was significantly higher (42.8 vs. 19.6%, p < 0.007) in patients with VAP than in those with VAT. According to the 2013 CDC definitions, 117 VAEs were identified: 113 (96%) were infection-related ventilator-associated complication-plus (IVAC-plus), while possible ventilator-associated pneumonia (PVAP) was found in 64 (56.6%) of them. VAE increased the number of ventilator days and prolonged ICU and hospital LOS (by 5, 11, and 12 days, respectively), with a trend towards increased 30-day mortality (43 vs 28%, p = 0.06). Most episodes (26, 55%) classified as IVAC-plus without PVAP criteria were due to atelectasis. PVAP significantly increased (p < 0.05) ventilator days as well as ICU and hospital LOS (by 10.5, 14, and 13 days, respectively). Only 24 (72.7%) of VAP and 15 (29.4%) of VAT episodes met IVAC-plus criteria.

Conclusions

Respiratory infections (mainly VAT) were the most common complication. VAE algorithms only identified events with surrogates of severe oxygenation deterioration. As a consequence, IVAC definitions missed one fourth of the episodes of VAP and three fourths of the episodes of VAT. Identifying VAT (often missed by IVAC-plus criteria) is important, as VAP and VAT have different impacts on mortality.

Electronic supplementary material

The online version of this article (10.1007/s00134-018-5269-7) contains supplementary material, which is available to authorized users.