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

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.

"Risk factors for ventilator-associated pneumonia following cardiac surgery: case-control study"

BACKGROUND

Ventilator-associated pneumonia (VAP) following cardiac surgery is a preventable complication associated with adverse outcomes.

AIMS

We aimed to assess risk factors and outcomes of VAP following cardiac surgery.

METHODS

A matched 1:3 case:control study, including adult patients undergoing cardiac surgery through sternotomy between Sep-2014 to Mar-2017 was conducted in a tertiary-care hospital in Israel. Cases included all patients developing VAP within 30 days after surgery, defined using consensus criteria. Controls were matched for age, gender and surgery type. Operative data were collected prospectively, other data were collected retrospectively. Cox regression was used for adjusted analysis of matched data.

FINDINGS

Out of 946 operated patients, we identified 57 patients with VAP after cardiac surgery (17.7 episodes per 1000 ventilator-days) matched to 149 controls. Significant independent risk factors for VAP included congestive heart failure (OR 2.357 95%CI 1.052-5.281), Chest re-exploration in ICU (OR 10.213 95%CI: 2.235-46.678), preoperative glucose levels (OR 1.1010 per 1 mg/dl increase 95%CI: 1.004-1.019) intraoperative red blood cell transfusions (OR 1.542 per 1 unit 95%CI: 1.109-2.094) and pulmonary hypertension (OR 2.261 95%CI 1.048-6.554). VAP was most commonly caused by Gram-negative pathogens. VAP was associated with higher mortality, longer length of stay, longer need for ventilator support and longer stay in ICU setting.

CONCLUSIONS

Postoperative VAP in cardiac surgery patients is associated with severe clinical outcomes. We identified risk factors that can aid in preventive measures implementation for high risk patients.

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.

Antimicrobial Stewardship Opportunities in Critically Ill Patients with Gram-Negative Lower Respiratory Tract Infections: A Multicenter Cross-Sectional Analysis

INTRODUCTION

Lower respiratory tract infections (LRTIs) are a major cause of morbidity and death. Because of changes in how LRTIs are defined coupled with the increasing prevalence of drug resistance, there is a gap in knowledge regarding the current burden of antimicrobial use for Centers for Disease Control and Prevention (CDC)-defined LRTIs. We describe the infection characteristics, antibiotic consumption, and clinical and economic outcomes of patients with Gram-negative (GN) LRTIs treated in intensive care units (ICUs).

METHODS

This was a retrospective, observational, cross-sectional study of adult patients treated in ICUs at two large academic medical centers in metropolitan Detroit, Michigan, from October 2013 to October 2015. To meet the inclusion criteria, patients must have had CDC-defined LRTI caused by a GN pathogen during ICU stay. Microbiological assessment of available Pseudomonas aeruginosa isolates included minimum inhibitory concentrations for key antimicrobial agents.

RESULTS

Four hundred and seventy-two patients, primarily from the community (346, 73.3%), were treated in medical ICUs (272, 57.6%). Clinically defined pneumonia was common (264, 55.9%). Six hundred and nineteen GN organisms were identified from index respiratory cultures: P. aeruginosa was common (224, 36.2%), with 21.6% of these isolates being multidrug resistant. Cefepime (213, 45.1%) and piperacillin/tazobactam (174, 36.8%) were the most frequent empiric GN therapies. Empiric GN therapy was inappropriate in 44.6% of cases. Lack of in vitro susceptibility (80.1%) was the most common reason for inappropriateness. Patients with inappropriate empiric GN therapy had longer overall stay, which translated to a median total cost of care of $79,800 (interquartile range $48,775 to $129,600) versus $68,000 (interquartile range $38,400 to $116,175), p = 0.013. Clinical failure (31.5% vs 30.0%, p = 0.912) and in-hospital all-cause mortality (26.4% vs 25.9%, p = 0.814) were not different.

CONCLUSION

Drug-resistant pathogens were frequently found and empiric GN therapy was inappropriate in nearly 50% of cases. Inappropriate therapy led to increased lengths of stay and was associated with higher costs of care.

Ventilator-associated respiratory infection in a resource-restricted setting: impact and etiology

Background

Ventilator-associated respiratory infection (VARI) is a significant problem in resource-restricted intensive care units (ICUs), but differences in casemix and etiology means VARI in resource-restricted ICUs may be different from that found in resource-rich units. Data from these settings are vital to plan preventative interventions and assess their cost-effectiveness, but few are available.

Methods

We conducted a prospective observational study in four Vietnamese ICUs to assess the incidence and impact of VARI. Patients ≥ 16 years old and expected to be mechanically ventilated > 48 h were enrolled in the study and followed daily for 28 days following ICU admission.

Results

Four hundred fifty eligible patients were enrolled over 24 months, and after exclusions, 374 patients’ data were analyzed. A total of 92/374 cases of VARI (21.7/1000 ventilator days) were diagnosed; 37 (9.9%) of these met ventilator-associated pneumonia (VAP) criteria (8.7/1000 ventilator days). Patients with any VARI, VAP, or VARI without VAP experienced increased hospital and ICU stay, ICU cost, and antibiotic use (p < 0.01 for all). This was also true for all VARI (p < 0.01 for all) with/without tetanus. There was no increased risk of in-hospital death in patients with VARI compared to those without (VAP HR 1.58, 95% CI 0.75–3.33, p = 0.23; VARI without VAP HR 0.40, 95% CI 0.14–1.17, p = 0.09). In patients with positive endotracheal aspirate cultures, most VARI was caused by Gram-negative organisms; the most frequent were Acinetobacter baumannii (32/73, 43.8%) Klebsiella pneumoniae (26/73, 35.6%), and Pseudomonas aeruginosa (24/73, 32.9%). 40/68 (58.8%) patients with positive cultures for these had carbapenem-resistant isolates. Patients with carbapenem-resistant VARI had significantly greater ICU costs than patients with carbapenem-susceptible isolates (6053 USD (IQR 3806–7824) vs 3131 USD (IQR 2108–7551), p = 0.04) and after correction for adequacy of initial antibiotics and APACHE II score, showed a trend towards increased risk of in-hospital death (HR 2.82, 95% CI 0.75–6.75, p = 0.15).

Conclusions

VARI in a resource-restricted setting has limited impact on mortality, but shows significant association with increased patient costs, length of stay, and antibiotic use, particularly when caused by carbapenem-resistant bacteria. Evidence-based interventions to reduce VARI in these settings are urgently needed.

Electronic supplementary material

The online version of this article (10.1186/s40560-017-0266-4) contains supplementary material, which is available to authorized users.

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.

From VAP to VAE: Implications of the New CDC Definitions on a Burn Intensive Care Unit Population

Ventilator-associated pneumonia (VAP) is a frequent complication of severe burn injury. Comparing the current ventilator-associated event-possible VAP definition to the pre-2013 VAP definition, we identified considerably fewer VAP cases in our burn ICU. The new definition does not capture many VAP cases that would have been reported using the pre-2013 definition. Infect Control Hosp Epidemiol 2017;38:867-869.

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.

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.

Is HELICS the Right Way? Lack of Chest Radiography Limits Ventilator-Associated Pneumonia Surveillance in Wales

Introduction: The reported incidence of ventilator-associated pneumonia (VAP) in Wales is low compared with surveillance data from other European regions. It is unclear whether this reflects success of the Welsh healthcare-associated infection prevention measures or limitations in the application of European VAP surveillance methods. Our primary aim was to investigate episodes of ventilator-associated respiratory tract infection (VARTI), to identify episodes that met established criteria for VAP, and to explore reasons why others did not, according to the Hospitals in Europe Link for Infection Control through Surveillance (HELICS) definitions.

Materials and Methods: During two 14-day study periods 2012–2014, investigators reviewed all invasively ventilated patients in all 14 Welsh Intensive Care Units (ICUs). Episodes were identified in which the clinical team had commenced antibiotic therapy because of suspected VARTI. Probability of pneumonia was estimated using a modified Clinical Pulmonary Infection Score (mCPIS). Episodes meeting HELICS definitions of VAP were identified, and reasons for other episodes not meeting definitions examined. In the second period, each patient was also assessed with regards to the development of a ventilator-associated event (VAE), according to recent US definitions.

Results: The study included 306 invasively ventilated patients; 282 were admitted to ICU for 48 h or more. 32 (11.3%) patients were commenced on antibiotics for suspected VARTI. Ten of these episodes met HELICS definitions of VAP, an incidence of 4.2 per 1000 intubation days. In 48% VARTI episodes, concurrent chest radiography was not performed, precluding the diagnosis of VAP. Mechanical ventilation (16.0 vs. 8.0 days; p = 0.01) and ICU stay (25.0 vs. 11.0 days; p = 0.01) were significantly longer in patients treated for VARTI compared to those not treated. There was no overlap between episodes of VARTI and of VAE.

Discussion: HELICS VAP surveillance definitions identified less than one-third of cases in which antibiotics were commenced for suspected ventilator-associated RTI. Lack of chest radiography precluded nearly 50% cases from meeting the surveillance definition of VAP, and as a consequence we are almost certainly underestimating the incidence of VAP in Wales.

Effects of a New Metabolic Conditioning Supplement on Perioperative Metabolic Stress and Clinical Outcomes: A Randomized, Placebo-Controlled Trial

BACKGROUND

Insulin resistance is a measure of metabolic stress in the perioperative period. Before now, no clinical trial has determined the summative effects of glutamine, L-carnitine, and antioxidants as metabolic conditioning supplements in the perioperative period.

OBJECTIVES

The purpose of this study was to determine the effects of a new conditioning supplement on perioperative metabolic stress and clinical outcomes in non-diabetic patients.

PATIENTS AND METHODS

In this randomized controlled trial, 89 non-diabetic patients scheduled for coronary artery bypass grafting, with ejection fractions above 30%, were selected. Using the balanced block randomization method, the patients were allocated to one of four study arms: 1) SP (supplement/placebo): supplement seven days before and placebo 30 days after the surgery; 2) PS: placebo before and supplement after the surgery; 3) SS: supplement before and after the surgery; and 4) PP: placebo before and after the surgery. The supplement was composed of glutamine, L-carnitine, vitamin C, vitamin E, and selenium, which was manufactured for the first time by this research team. Five blood samples were drawn: seven days preoperatively, at the entrance to the operating room, while leaving the operating room, seven days postoperatively, and 30 days postoperatively. Levels of glucose, insulin, and HbA1c were measured in blood samples. Insulin resistance and sensitivity were calculated using a formula. Surgical complications were assessed 30 days postoperatively. Data analysis was done using one-way ANOVA, the Chi-square test, and a general linear model repeated-measures analysis with Bonferroni adjustment.

RESULTS

Blood glucose levels were increased postoperatively in the four groups (< 0.001), but a significantly higher increase occurred in the PP group compared to the SP (0.027), PS (0.026), and SS (0.004) groups. The superficial wound infection rate was significantly different between the four groups (0.021): 26.08% in PP, 9.09% in SP, 4.54% in PS, and 0% in SS.

CONCLUSIONS

Our new metabolic conditioning supplement, whether given pre- or postoperatively, led to better perioperative glycemic control and decreased postsurgical wound infections in non-diabetic patients.