Association of Endotracheal Aspirate Culture Variability and Antibiotic Use in Mechanically Ventilated Pediatric Patients

Outcomes associated with ventilator-associated events (VAE), respiratory infections (VARI), pneumonia (VAP) and tracheobronchitis (VAT) in ventilated pediatric ICU patients: A multicentre prospective cohort study

OBJECTIVES

An objective categorization of respiratory infections based on outcomes is an unmet clinical need. Ventilator-associated pneumonia and tracheobronchitis remain used in clinical practice, whereas ventilator-associated events (VAE) are limited to surveillance purposes.

RESEARCH METHODOLOGY/DESIGN

This was a secondary analysis from a multicentre observational prospective cohort study. VAE were defined as a sustained increase in minimum Oxygen inspired fraction (FiO2) and/or Positive end-expiratory pressures (PEEP) of ≥ 0.2/2 cm H2O respectively, or an increase of 0.15 FiO2 + 1 cm H20 positive end-expiratory pressures for ≥ 1 calendar-day.

SETTING

15 Paediatric Intensive Care Units.

MAIN OUTCOME MEASURES

Mechanical ventilation duration, intensive care and hospital length of stay; (LOS) and mortality.

RESULTS

A cohort of 391 ventilated children with an age (median, [Interquartile Ranges]) of 1 year[0.2-5.3] and 7 days[5-10] of mechanical ventilation were included. Intensive care and hospital stays were 11 [7-19] and 21 [14-39] days, respectively. Mortality was 5.9 %. Fifty-eight ventilator-associated respiratory infections were documented among 57 patients: Seventeen (29.3 %) qualified as ventilator-associated pneumonia (VAP) and 41 (70.7 %) as ventilator-associated tracheobronchitis (VAT). Eight pneumonias and 16 tracheobronchitis (47 % vs 39 %,P = 0.571) required positive end-expiratory pressure or oxygen increases consistent with ventilator-associated criteria. Pneumonias did not significantly impact on outcomes when compared to tracheobronchitis. In contrast, infections (pneumonia or tracheobronchitis) following VAEs criteria were associated with > 6, 8 and 15 extra-days of ventilation (16 vs 9.5, P = 0.001), intensive care stay (23.5 vs 15; P = 0.004) and hospital stay (39 vs 24; P = 0.015), respectively.

CONCLUSION

When assessing ventilated children with respiratory infections, VAE apparently is associated with higher ventilator-dependency and LOS compared with pneumonia or tracheobronchitis.

IMPLICATIONS FOR PRACTICE

Incorporating the modification of ventilatory settings for further categorization of the respiratory infections may facilitate therapeutic management among ventilated patients.

Evaluation of a Comprehensive Algorithm for PICU Patients With New Fever or Instability: Association of Clinical Decision Support With Testing Practices

OBJECTIVES

Previously, we implemented a comprehensive decision support tool, a "New Fever Algorithm," to support the evaluation of PICU patients with new fever or instability. This tool was associated with a decline in culture rates without safety concerns. We assessed the impact of the algorithm on testing practices by identifying the proportion of cultures pre- vs. post-implementation that were discordant with algorithm guidance and may have been avoidable.

DESIGN

Retrospective evaluation 12 months pre- vs. post-quality improvement intervention.

SETTING

Single-center academic PICU and pediatric cardiac ICU.

SUBJECTS

All admitted patients.

INTERVENTIONS

Implementing the "New Fever Algorithm" in July 2020.

MEASUREMENTS AND MAIN RESULTS

Patient medical records were reviewed to categorize indications for all blood, respiratory, and urine cultures. Among cultures obtained for new fever or new clinical instability, we assessed specific testing patterns that were discordant from the algorithm's guidance such as blood cultures obtained without documented concern for sepsis without initiation of antibiotics, respiratory cultures without respiratory symptoms, urine cultures without a urinalysis or pyuria, and pan-cultures (concurrent blood, respiratory, and urine cultures). Among 2827 cultures, 1950 (69%) were obtained for new fever or instability. The proportion of peripheral blood cultures obtained without clinical concern for sepsis declined from 18.6% to 10.4% (p < 0.0007). Respiratory cultures without respiratory symptoms declined from 41.5% to 27.4% (p = 0.01). Urine cultures without a urinalysis did not decline (from 27.6% to 25.1%). Urine cultures without pyuria declined from 83.0% to 73.7% (p = 0.04). Pan-cultures declined from 22.4% to 10.6% (p < 0.0001). Overall, algorithm-discordant testing declined from 39% to 30% (p < 0.0001).

CONCLUSIONS

The majority of cultures obtained were for new fever or instability and introduction of the "New Fever Algorithm" was associated with reductions in algorithm-discordant testing practices and pan-cultures. There remain opportunities for improvement and additional strategies are warranted to optimize testing practices for in this complex patient population.

Quality Improvement Project Reducing Sputum Cultures for Pediatric Patients With a Tracheostomy

BACKGROUND AND OBJECTIVES

Current research implies overuse of diagnostic testing and overtreatment in children with tracheostomies. There are no guidelines for obtaining sputum cultures for these patients, yet they are commonly obtained without significantly affecting management or outcomes. The aim of our quality improvement project was to decrease rate of sputum cultures in this population by 50%, from 64% to 32%.

METHODS

This was a single-center quality improvement project conducted in a pediatric emergency department (ED). Key drivers included: Standardized decision-making, appropriate culture collection, knowledge regarding colonization versus clinically relevant growth, and viral versus bacterial infections in this population. The study team developed an algorithm, used modification to electronic medical records orders, and provided education to drive change. Six months of preintervention and 12 months postintervention data were collected. Run charts/statistical process charts were created for the rate of cultures, length of stay, and return to the ED.

RESULTS

There were 159 patient encounters and the rate of sputum cultures decreased from 64% at baseline to 25% without change in length of stay or increased rate at which patients returned to the ED, including during local coronavirus disease 2019 and respiratory syncytial virus surges. We observed nonrandom data patterns after introduction of algorithm resulting in centerline shifts.

CONCLUSIONS

The study team was able to introduce an algorithm coinciding with a reduction in number of sputum cultures obtained. Next steps would be determining safety and efficacy of such an algorithm over a larger population.

Repeat tracheal aspirate cultures in pediatric intensive care patients: Frequency, resistance, and antimicrobial use

OBJECTIVE

To evaluate the clinical impact and features associated with repeat tracheal aspirate (TA) cultures in children admitted to the intensive care unit.

DESIGN

Retrospective cohort study.

SETTING

A 338-bed freestanding, tertiary pediatric academic medical center with pediatric medical intensive care unit (PICU) and cardiac intensive care units (CICU).

PATIENTS

Children ≤18 years of age who were admitted to either the PICU or CICU who had ≥2 TA cultures in a single intensive care admission.

METHODS

Patients with ≥2 TA cultures between 2018 and 2019 were included in this study. The following information was collected: patient demographics, clinical data summarizing patient condition at the time of culture collection, number of TA cultures per patient, antibiotic usage, and microbiologic data. Descriptive statistics established the frequency of TA collection, time between culturing, clinical reasoning for collection, antibiotic exposure, and development of multidrug-resistant organisms (MDRO).

RESULTS

Sixty-three patients had repeat TA cultures and accounted for 252 TA cultures during the study period. Most patients with repeat TA cultures were admitted to the PICU (71%) and were male (65%). A median of 3 TA cultures per patient were obtained with 50% of repeat cultures occurring within 7 days from the previous culture. Sixty-six percent of patients had the same organism cultured on ≥2 TA cultures. Most antibiotics were not modified or continued to treat the results of the TA culture.

CONCLUSIONS

Repeat TA cultures frequently show the same pathogens, and results do not often influence antibiotic selection or usage. Repeat TA cultures did demonstrate the development of MDROs.

Breaking Boundaries in Pneumonia Diagnostics: Transitioning from Tradition to Molecular Frontiers with Multiplex PCR

The advent of rapid molecular microbiology testing has revolutionized infectious disease diagnostics and is now impacting pneumonia diagnosis and management. Molecular platforms offer highly multiplexed assays for diverse viral and bacterial detection, alongside antimicrobial resistance markers, providing the potential to significantly shape patient care. Despite the superiority in sensitivity and speed, debates continue regarding the clinical role of multiplex molecular testing, notably in comparison to standard methods and distinguishing colonization from infection. Recent guidelines endorse molecular pneumonia panels for enhanced sensitivity and rapidity, but implementation requires addressing methodological differences and ensuring clinical relevance. Diagnostic stewardship should be leveraged to optimize pneumonia testing, emphasizing pre- and post-analytical strategies. Collaboration between clinical microbiologists and bedside providers is essential in developing implementation strategies to maximize the clinical utility of multiplex molecular diagnostics in pneumonia. This narrative review explores these multifaceted issues, examining the current evidence on the clinical performance of multiplex molecular assays in pneumonia, and reflects on lessons learned from previous microbiological advances. Additionally, given the complexity of pneumonia and the sensitivity of molecular diagnostics, diagnostic stewardship is discussed within the context of current literature, including implementation strategies that consider pre-analytical and post-analytical modifications to optimize the clinical utility of advanced technologies like multiplex PCR.

Practice Versus Potential: The Impact of the BioFire FilmArray Pneumonia Panel on Antibiotic Use in Children

BACKGROUND

The BioFire FilmArray Pneumonia Panel (BFPP), a multiplex PCR panel for the diagnosis of lower respiratory tract infections, has been proposed as a tool for antimicrobial stewardship. Few studies evaluate real-world implementation of the BFPP and no studies focus exclusively on children. Our institution implemented BFPP testing without restrictions.

METHODS

We conducted a retrospective cohort study in children hospitalized at St. Louis Children's Hospital to (1) characterize the use of the BFPP in pediatric patients and (2) assess how results impacted antibiotic use. We included all BFPP tests obtained during the first year after the introduction of the test, September 2021 through August 2022. The primary outcome was change in antibiotic therapy within 24 hours of results, which was compared to the potential change in antibiotic therapy determined by two infectious diseases clinicians.

RESULTS

One hundred sixty-nine tests from 126 patients were included. Nine patients were immunocompromised and 19 had chronic tracheostomy. The majority of tests were sent from tracheal aspirate specimens (92%) and from patients in an intensive care unit (94%). Only 51% of tests were obtained due to respiratory failure or suspected pneumonia. For 80% of test results, there was potential to change antibiotics, but change occurred in only 46% of tests in practice. Antibiotic escalation was more common (26%) than de-escalation (15%) or discontinuation (4.1%).

CONCLUSIONS

In a cohort of pediatric patients tested with the BFPP, the majority of tests were sent from tracheal aspirates and less than half of tests were associated with a change in antibiotics.

Analysis of risk factors for acute attacks complicated by respiratory failure in children with asthma

Objective

To describe the proportion and clinical characteristics of hospitalized children with acute asthma attacks complicated by respiratory failure and to analyze the risk factors.

Methods

This retrospective study analyzed hospital admissions of children and adolescents with acute asthma attacks between January 2016 and December 2021. Inclusion criteria were used to identify eligible cases, and demographic information and disease characteristics were collected. Patients were categorized into respiratory failure group and the other group based on the result of artery blood gas analysis. Multivariate logistic regression was utilized to investigate the risk factors associated with respiratory failure resulting from acute asthma attacks. The data were analyzed using SPSS 22.0, and significance was considered at P < 0.05.

Results

Our research involved 225 participants, with 18.7% diagnosed with respiratory failure. The respiratory failure group was found to be younger and have higher percentage of male, while birth weight, nationality, and type of residence did not differ between the two groups. In the respiratory failure group, a significant difference was observed in emergency hospitalization, ICU treatment, severe to critical attack, dyspnea and allergy history. The two groups did not differ in admission season, first asthma diagnosis, respiratory infection and comorbidity. The respiratory failure group exhibited a higher proportion of atopy-only asthma and a lower proportion of T2-high asthma. The eosinophil count, and eosinophil percentage were lower in the respiratory failure group, while neutrophil count was higher. Having a history of allergies (OR = 2.46, 95% CI: 1.08-5.59) and neutrophil count (OR = 1.10, 95% CI: 1.00-1.21) were the risk factors for respiratory failure in children with asthma. There also existed that the risk of respiratory failure increases with decreasing age of the children (OR = 0.85, 95% CI: 0.73-0.99).

Conclusion

Notably, risk factors for respiratory failure in hospitalized asthma children include age, having a history of allergies, and neutrophil count. The identification of the above factors and the implementation of timely intervention can optimize the treatment of asthma in children.

A Survey of PICU Clinician Practices and Perceptions regarding Respiratory Cultures in the Evaluation of Ventilator-Associated Infections in the BrighT STAR Collaborative

OBJECTIVES

To characterize respiratory culture practices for mechanically ventilated patients, and to identify drivers of culture use and potential barriers to changing practices across PICUs.

DESIGN

Cross-sectional survey conducted May 2021-January 2022.

SETTING

Sixteen academic pediatric hospitals across the United States participating in the BrighT STAR Collaborative.

SUBJECTS

Pediatric critical care medicine physicians, advanced practice providers, respiratory therapists, and nurses.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We summarized the proportion of positive responses for each question within a hospital and calculated the median proportion and IQR across hospitals. We correlated responses with culture rates and compared responses by role. Sixteen invited institutions participated (100%). Five hundred sixty-eight of 1,301 (44%) e-mailed individuals completed the survey (median hospital response rate 60%). Saline lavage was common, but no PICUs had a standardized approach. There was the highest variability in perceived likelihood (median, IQR) to obtain cultures for isolated fever (49%, 38-61%), isolated laboratory changes (49%, 38-57%), fever and laboratory changes without respiratory symptoms (68%, 54-79%), isolated change in secretion characteristics (67%, 54-78%), and isolated increased secretions (55%, 40-65%). Respiratory cultures were likely to be obtained as a "pan culture" (75%, 70-86%). There was a significant correlation between higher culture rates and likelihood to obtain cultures for isolated fever, persistent fever, isolated hypotension, fever, and laboratory changes without respiratory symptoms, and "pan cultures." Respondents across hospitals would find clinical decision support (CDS) helpful (79%) and thought that CDS would help align ICU and/or consulting teams (82%). Anticipated barriers to change included reluctance to change (70%), opinion of consultants (64%), and concern for missing a diagnosis of ventilator-associated infections (62%).

CONCLUSIONS

Respiratory culture collection and ordering practices were inconsistent, revealing opportunities for diagnostic stewardship. CDS would be generally well received; however, anticipated conceptual and psychologic barriers to change must be considered.

Antimicrobial Stewardship and Improved Antibiotic Utilization in the Pediatric Cardiac Intensive Care Unit

Background

We developed a multidisciplinary antimicrobial stewardship team to optimize antimicrobial use within the Pediatric Cardiac Intensive Care Unit. A quality improvement initiative was conducted to decrease unnecessary broad-spectrum antibiotic use by 20%, with sustained change over 12 months.

Methods

We conducted this quality improvement initiative within a quaternary care center. PDSA cycles focused on antibiotic overuse, provider education, and practice standardization. The primary outcome measure was days of therapy (DOT)/1000 patient days. Process measures included electronic medical record order-set use. Balancing measures focused on alternative antibiotic use, overall mortality, and sepsis-related mortality. Data were analyzed using statistical process control charts.

Results

A significant and sustained decrease in DOT was observed for vancomycin and meropenem. Vancomycin use decreased from a baseline of 198 DOT to 137 DOT, a 31% reduction. Meropenem use decreased from 103 DOT to 34 DOT, a 67% reduction. These changes were sustained over 24 months. The collective use of gram-negative antibiotics, including meropenem, cefepime, and piperacillin-tazobactam, decreased from a baseline of 323 DOT to 239 DOT, a reduction of 26%. There was no reciprocal increase in cefepime or piperacillin-tazobactam use. Key interventions involved electronic medical record changes, including automatic stop times and empiric antibiotic standardization. All-cause mortality remained unchanged.

Conclusions

The initiation of a dedicated antimicrobial stewardship initiative resulted in a sustained reduction in meropenem and vancomycin usage. Interventions did not lead to increased utilization of alternative broad-spectrum antimicrobials or increased mortality. Future interventions will target additional broad-spectrum antimicrobials.

Nonbronchoscopic Bronchoalveolar Lavage Improves Respiratory Culture Accuracy in Critically Ill Patients

OBJECTIVES

Diagnosis of pneumonia is challenging in critically ill, intubated patients due to limited diagnostic modalities. Endotracheal aspirate (EA) cultures are standard of care in many ICUs; however, frequent EA contamination leads to unnecessary antibiotic use. Nonbronchoscopic bronchoalveolar lavage (NBBL) obtains sterile, alveolar cultures, avoiding contamination. However, paired NBBL and EA sampling in the setting of a lack of gold standard for airway culture is a novel approach to improve culture accuracy and limit antibiotic use in the critically ill patients.

DESIGN

We designed a pilot study to test respiratory culture accuracy between EA and NBBL. Adult, intubated patients with suspected pneumonia received concurrent EA and NBBL cultures by registered respiratory therapists. Respiratory culture microbiology, cell counts, and antibiotic prescribing practices were examined.

SETTING

We performed a prospective pilot study at the Cleveland Clinic Main Campus Medical ICU in Cleveland, Ohio for 22 months from May 2021 through March 2023.

PATIENTS OR SUBJECTS

Three hundred forty mechanically ventilated patients with suspected pneumonia were screened. Two hundred fifty-seven patients were excluded for severe hypoxia (Fio2 ≥ 80% or positive end-expiratory pressure ≥ 12 cm H2O), coagulopathy, platelets less than 50,000, hemodynamic instability as determined by the treating team, and COVID-19 infection to prevent aerosolization of the virus.

INTERVENTIONS

All 83 eligible patients were enrolled and underwent concurrent EA and NBBL.

MEASUREMENTS AND MAIN RESULTS

More EA cultures (42.17%) were positive than concurrent NBBL cultures (26.51%, p = 0.049), indicating EA contamination. The odds of EA contamination increased by eight-fold 24 hours after intubation. EA was also more likely to be contaminated with oral flora when compared with NBBL cultures. There was a trend toward decreased antibiotic use in patients with positive EA cultures if paired with a negative NBBL culture. Alveolar immune cell populations were recovered from NBBL samples, indicating successful alveolar sampling. There were no major complications from NBBL.

CONCLUSIONS

NBBL is more accurate than EA for respiratory cultures in critically ill, intubated patients. NBBL provides a safe and effective technique to sample the alveolar space for both clinical and research purposes.

Implementation of a 24-hour infection diagnosis protocol in the pediatric cardiac intensive care unit (CICU)

OBJECTIVES

To reduce unnecessary antibiotic exposure in a pediatric cardiac intensive care unit (CICU).

DESIGN

Single-center, quality improvement initiative. Monthly antibiotic utilization rates were compared between 12-month baseline and 18-month intervention periods.

SETTING

A 25-bed pediatric CICU.

PATIENTS

Clinically stable patients undergoing infection diagnosis were included. Patients with immunodeficiency, mechanical circulatory support, open sternum, and recent culture-positive infection were excluded.

INTERVENTIONS

The key drivers for improvement were standardizing the infection diagnosis process, order-set creation, limitation of initial antibiotic prescription to 24 hours, discouraging indiscriminate vancomycin use, and improving bedside communication and situational awareness regarding the infection diagnosis protocol.

RESULTS

In total, 109 patients received the protocol; antibiotics were discontinued in 24 hours in 72 cases (66%). The most common reasons for continuing antibiotics beyond 24 hours were positive culture (n = 13) and provider preference (n = 13). A statistical process control analysis showed only a trend in monthly mean antibiotic utilization rate in the intervention period compared to the baseline period: 32.6% (SD, 6.1%) antibiotic utilization rate during the intervention period versus 36.6% (SD, 5.4%) during the baseline period (mean difference, 4%; 95% CI, -0.5% to -8.5%; P = .07). However, a special-cause variation represented a 26% reduction in mean monthly vancomycin use during the intervention period. In the patients who had antibiotics discontinued at 24 hours, delayed culture positivity was rare.

CONCLUSIONS

Implementation of a protocol limiting empiric antibiotic courses to 24 hours in clinically stable, standard-risk, pediatric CICU patients with negative cultures is feasible. This practice appears safe and may reduce harm by decreasing unnecessary antibiotic exposure.

A Novel Comprehensive Algorithm for Evaluation of PICU Patients With New Fever or Instability

OBJECTIVES

There is variation in microbiology testing among PICU patients with fever offering opportunities to reduce avoidable testing and treatment. Our objective is to describe the development and assess the impact of a novel comprehensive testing algorithm to support judicious testing practices and expanded diagnostic differentials for PICU patients with new fever or instability.

DESIGN

A mixed-methods quality improvement study.

SETTING

Single-center academic PICU and pediatric cardiac ICU.

SUBJECTS

Admitted PICU patients and physicians.

INTERVENTIONS

A multidisciplinary team developed a clinical decision-support algorithm.

MEASUREMENTS AND MAIN RESULTS

We evaluated blood, endotracheal, and urine cultures, urinalyses, and broad-spectrum antibiotic use per 1,000 ICU patient-days using statistical process control charts and incident rate ratios (IRRs) and assessed clinical outcomes 24 months pre- and 18 months postimplementation. We surveyed physicians weekly for 12 months postimplementation. Blood cultures declined by 17% (IRR, 0.83; 95% CI, 0.77-0.89), endotracheal cultures by 26% (IRR, 0.74; 95% CI, 0.63-0.86), and urine cultures by 36% (IRR, 0.64; 95% CI, 0.56-0.73). There was an anticipated rise in urinalysis testing by 23% (IRR, 1.23; 95% CI, 1.14-1.33). Despite higher acuity and fewer brief hospitalizations, mortality, hospital, and PICU readmissions were stable, and PICU length of stay declined. Of the 108 physician surveys, 46 replied (43%), and 39 (85%) recently used the algorithm; 0 reported patient safety concerns, two (4%) provided constructive feedback, and 28 (61%) reported the algorithm improved patient care.

CONCLUSIONS

A comprehensive fever algorithm was associated with reductions in blood, endotracheal, and urine cultures and anticipated increase in urinalyses. We detected no patient harm, and physicians reported improved patient care.

Respiratory culture organism isolation and test characteristics in children with tracheostomies with and without acute respiratory infection

BACKGROUND

Among children with tracheostomies, little is known about how respiratory culture results differ between states with and without acute respiratory infections (ARI), or the overall test performance of respiratory cultures.

OBJECTIVE

To determine the association of respiratory culture organism isolation with diagnosis of ARI in children with tracheostomies, and assess test characteristics of respiratory cultures in the diagnosis of bacterial ARI (bARI).

METHODS

This single-center, retrospective cohort study included respiratory cultures of children with tracheostomies obtained between 2010 and 2018. The primary predictor was ARI diagnosis code at the time of culture; the primary outcomes were respiratory culture organism isolation and species identified. Generalized estimating equations were used to assess for association between ARI diagnosis and isolation of any organism while controlling for potential confounders and accounting for within-patient clustering. A multinomial logistic regression equation assessed for association with specific species. Test characteristics were calculated using bARI diagnosis as the reference standard.

RESULTS

Among 3578 respiratory cultures from 533 children (median 4 cultures/child, interquartile range (IQR): 1-9), 25.9% were obtained during ARI and 17.2% had ≥1 organism. Children with ARI diagnosis had higher odds of organism identification (adjusted odds ratio 1.29, 95%  confidence interval [CI] 1.16-1.44). When controlling for covariates, ARI was associated with isolation of Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, and Streptococcus pyogenes. Test characteristics revealed a 24.3% sensitivity, 85.2% specificity, 36.5% positive predictive value, and 76.3% negative predictive value in screening for bARI.

CONCLUSION

The utility of respiratory culture testing to screen for, diagnose, and direct treatment of ARI in children with tracheostomies is limited.

Mixed-methods process evaluation of a respiratory-culture diagnostic stewardship intervention

OBJECTIVE

To conduct a process evaluation of a respiratory culture diagnostic stewardship intervention.

DESIGN

Mixed-methods study.

SETTING

Tertiary-care pediatric intensive care unit (PICU).

PARTICIPANTS

Critical care, infectious diseases, and pulmonary attending physicians and fellows; PICU nurse practitioners and hospitalist physicians; pediatric residents; and PICU nurses and respiratory therapists.

METHODS

This mixed-methods study was conducted concurrently with a diagnostic stewardship intervention to reduce the inappropriate collection of respiratory cultures in mechanically ventilated children. We quantified baseline respiratory culture utilization and indications for ordering using quantitative methods. Semistructured interviews informed by these data and the Consolidated Framework for Implementation Research (CFIR) were then performed, recorded, transcribed, and coded to identify salient themes. Finally, themes identified in these interviews were used to create a cross-sectional survey.

RESULTS

The number of cultures collected per day of service varied between attending physicians (range, 2.2-27 cultures per 100 days). In total, 14 interviews were performed, and 87 clinicians completed the survey (response rate, 47%) and 77 nurses or respiratory therapists completed the survey (response rate, 17%). Clinicians varied in their stated practices regarding culture ordering, and these differences both clustered by specialty and were associated with perceived utility of the respiratory culture. Furthermore, group "default" practices, fear, and hierarchy were drivers of culture orders. Barriers to standardization included fear of a missed diagnosis and tension between practice standardization and individual decision making.

CONCLUSIONS

We identified significant variation in utilization and perceptions of respiratory cultures as well as several key barriers to implementation of this diagnostic test stewardship intervention.

Impact of Organism Reporting from Endotracheal Aspirate Cultures on Antimicrobial Prescribing Practices in Mechanically Ventilated Pediatric Patients

Endotracheal aspirate cultures (EACs) help diagnose lower respiratory tract infections in mechanically ventilated patients but are limited by contamination with normal microbiota and variation in laboratory reporting. Increased use of EACs is associated with increased antimicrobial prescribing, but the impact of microbiology reporting on prescribing practices is unclear. This study was a retrospective analysis of EACs from mechanically ventilated patients at Children's Hospital Colorado (CHCO) admitted between 1 January 2019 and 31 December 2019. Chart review was performed to collect all culture and Gram stain components, as well as antibiotic use directed to organisms in culture. Reporting concordance was determined for each organism using American Society for Microbiology guidelines. Days of therapy were calculated for overreported and guideline-concordant organisms. A multivariable model was used to assess the relationship between organism reporting and total days of therapy. Overall, 448 patients with 827 EACs were included in this study. Among patients with tracheostomy, 25 (8%) organisms reported from EACs were overreported and contributed 48 days of excess therapy, while 227 (29%) organisms from the EACs of endotracheally intubated patients were overreported, contributing 472 excess days of therapy. After adjustment, organism overreporting was associated with a >2-fold-higher rate of antimicrobial therapy than guideline-concordant reporting (incident rate ratio [IRR], 2.83; 95% confidence interval [CI], 1.23, 6.53; P < 0.05). Overreported organisms from respiratory cultures contribute to excess antimicrobial therapy exposure in mechanically ventilated patients. Microbiology laboratories have an opportunity to mitigate antimicrobial overuse through standardized reporting practices.

Early molecular markers of ventilator-associated pneumonia in bronchoalveolar lavage in preterm infants

INTRODUCTION

Ventilator-associated pneumonia (VAP) constitutes a serious nosocomial infection. Our aim was to evaluate the reliability of cytokines and oxidative stress/inflammation biomarkers in bronchoalveolar lavage fluid (BALF) and tracheal aspirates (TA) as early biomarkers of VAP in preterm infants.

METHODS

Two cohorts were enrolled, one to select candidates and the other for validation. In both, we included preterms with suspected VAP, according to BALF culture, they were classified into confirmed VAP and no VAP. Concentration of 16 cytokines and 8 oxidative stress/inflammation biomarkers in BALF and TA was determined in all patients.

RESULTS

In the first batch, IL-17A and TNF-α in BALF, and in the second one IL-10, IL-6, and TNF-α in BALF were significantly higher in VAP patients. BALF TNF-α AUC in both cohorts was 0.86 (sensitivity 0.83, specificity 0.88). No cytokine was shown to be predictive of VAP in TA. A statistically significant increase in the VAP group was found for glutathione sulfonamide (GSA) in BALF and TA.

CONCLUSIONS

TNF-α in BALF and GSA in BALF and TA were associated with VAP in preterm newborns; thus, they could be used as early biomarkers of VAP. Further studies with an increased number of patients are needed to confirm these results.

IMPACT

We found that TNF-α BALF and GSA in both BALF and TA are capable of discriminating preterm infants with VAP from those with pulmonary pathology without infection. This is the first study in preterm infants aiming to evaluate the reliability of cytokines and oxidative stress/inflammation biomarkers in BALF and TA as early diagnostic markers of VAP. We have validated these results in two independent cohorts of patients. Previously studies have focused on full-term neonates and toddlers and determined biomarkers mostly in TA, but none was exclusively conducted in preterm infants.

A retrospective evaluation of multiple definitions for ventilator associated pneumonia (VAP) diagnosis in an Australian regional intensive care unit

BACKGROUND

Ventilator Associated Pneumonia is a common complication of invasively ventilated patients with significant and underestimated morbidity and mortality. Defining VAP cases is greatly varied as many definitions are used with varying success and sensitivity. This study evaluates VAP detection using four definitions in a regional Australian Intensive Care Unit (ICU).

METHODS

A cohort of patients admitted to ICU at the Mackay Base Hospital from April 1st 2020 to March 31st 2021, who had endo-tracheal intubation and mechanical ventilation for longer than 48 h were identified. Each patient was examined across four common definitions of VAP. Head-to-head analysis of definitions was pursued to determine the most suitable definition. The four definitions used included: An Australian VAP definition, the CDC VAP definition, the Mackay Base Hospital Local Protocol and a Physician Decision Arm.

RESULTS

66 unique patients and 2 re-intubations were identified during the data collection window. The local protocol identified 8 cases of VAP. The Australian VAP definition identified 6 additional cases and 0 missed cases compared to the local protocol. The CDC definition missed 4 cases and identified 4 additional cases compared to the local protocol. Finally, the physician arm identified 10 cases including 8 additional cases and missed 6 cases.

CONCLUSIONS

VAP is an extremely difficult clinical condition to define and detect. Definitions have varied accuracy and suffer logistically for application to the individual patient. Refined criteria for diagnosis of VAP is greatly needed and its prevalence in intensive care units likely remains uncertain.