Daily Respiratory Research Analysis
Three impactful respiratory papers stand out today: an international Delphi consensus refines how we define and subphenotype ARDS, a cohort study links lower respiratory tract cytomegalovirus reactivation to doubled mortality in the ICU with context-dependent antiviral effects, and a multicenter real‑world study shows FeNO suppression testing can curb biologic use in severe asthma without compromising outcomes.
Summary
Three impactful respiratory papers stand out today: an international Delphi consensus refines how we define and subphenotype ARDS, a cohort study links lower respiratory tract cytomegalovirus reactivation to doubled mortality in the ICU with context-dependent antiviral effects, and a multicenter real‑world study shows FeNO suppression testing can curb biologic use in severe asthma without compromising outcomes.
Research Themes
- Refining ARDS definitions and advancing subphenotyping
- Viral reactivation in the lower respiratory tract and ICU outcomes
- Precision stewardship in severe asthma using FeNO suppression testing
Selected Articles
1. Defining and subphenotyping ARDS: insights from an international Delphi expert panel.
An international four‑round Delphi process achieved consensus on a conceptual model of ARDS, the key elements to include in definitions across research, education, and clinical care, and prioritized subphenotyping as a research and implementation need. The panel underscores refining ARDS criteria to better capture clinical and biological heterogeneity and to enhance diagnostic precision.
Impact: This consensus will influence trial design, bedside diagnosis, and education by promoting trait-based definitions and subphenotyping of ARDS.
Clinical Implications: Clinicians should anticipate incorporation of trait-based criteria and subphenotyping into ARDS pathways, enabling more precise enrollment in trials and potentially phenotype-guided therapies.
Key Findings
- Four-round international Delphi achieved consensus on a conceptual ARDS model and key definitional components across research, education, and clinical care.
- Subphenotyping ARDS was prioritized as a key research and implementation target to address heterogeneity.
- The process used anonymous rounds and quantitative thresholds to reduce bias, highlighting gaps and research priorities for future work.
Methodological Strengths
- Rigorous multi-round Delphi with anonymous voting and predefined quantitative criteria
- Global, multidisciplinary expert representation
Limitations
- Consensus-based position without new patient-level data
- Potential selection bias in expert panel composition and need for empirical validation
Future Directions: Empirically validate proposed definitional components and subphenotypes, integrate biomarkers and imaging, and test phenotype-guided interventions in trials.
Although the definition of acute respiratory distress syndrome (ARDS) has undergone numerous revisions aimed at enhancing its diagnostic accuracy and clinical practicality, the usefulness and precision of these definitions remain matters of ongoing discussion. In this Position Paper, we report on a Delphi study to reach a consensus on the conceptual model of ARDS, specifically identifying its defining components within clinical, research, and educational contexts as well as exploring the potential role of subphenotyping. We did a four-round Delphi study, involving experts in ARDS research and management from a diverse range of geoeconomic regions and professional backgrounds. Consensus was achieved for the conceptual model of ARDS; key components to be included for an ARDS definition in the context of research, education, and patient management; and the need for further research in subphenotyping ARDS. Additionally, we highlight knowledge gaps and research priorities that could guide future investigations in this area. Our study builds on previous non-Delphi-based consensus processes (eg, the new global definition of ARDS and recent society-based guidelines) by using a rigorous Delphi method that ensured panellist anonymity and used clear quantitative criteria to mitigate potential peer pressure and group conformity. The findings underscore the need to refine the ARDS definition to better account for the heterogeneity of clinical presentations and underlying pathophysiology, and to improve diagnostic precision, including the use of subphenotyping where appropriate.
2. Exploring the Long-Term Utility of Remotely Monitored FeNO Suppression Testing in Severe Asthma.
In a seven‑center prospective real‑world cohort (n=353), 72.8% completed FeNO suppression testing and 54.5% were positive. Positive FeNOSuppT, delivered with digital inhaler monitoring, was associated with greater short‑term FEV1% improvement and lower biologic initiation rates, while long‑term outcomes were maintained.
Impact: Demonstrates feasible, scalable stewardship to reduce unnecessary biologic therapy in severe asthma by validating adherence with FeNO suppression testing.
Clinical Implications: Incorporate FeNO suppression testing with digital adherence monitoring before biologic initiation in severe asthma pathways to optimize therapy and costs.
Key Findings
- Among 353 severe asthma patients, 72.8% completed FeNOSuppT and 54.5% were positive (>42% FeNO reduction).
- Positive FeNOSuppT was associated with greater short‑term improvement in FEV1% predicted.
- Positive FeNOSuppT correlated with lower biologic initiation rates without deterioration in long‑term clinical outcomes.
Methodological Strengths
- Prospective multicenter real‑world design with digital adherence monitoring
- Clinically relevant short‑ and long‑term outcomes assessed
Limitations
- Non-randomized observational design with potential residual confounding
- Incomplete reporting of exact effect sizes for all outcomes in abstract and potential selection bias (completion rate 72.8%)
Future Directions: Randomized pragmatic trials comparing FeNOSuppT-guided pathways versus standard care and cost‑effectiveness analyses across health systems.
BACKGROUND: Confirmation of optimal inhaled corticosteroid use is essential before initiating biologic therapy. Fractional exhaled nitric oxide (FeNO) suppression testing (FeNOSuppT) is a proven phenotyping technique; however, its long-term effect on clinical outcomes remains unclear. OBJECTIVES: To assess the real-world feasibility of delivering FeNOSuppT alongside digital inhaler monitoring and to examine its effect on biologic initiation and clinical outcomes. METHODS: Prospective cohort study within 7 U.K. severe asthma centers. Patients received a sensor-enabled inhaled corticosteroid/long-acting β-agonist (ICS/LABA) inhaler during an initial appointment between July 2020 and June 2022. A positive FeNOSuppT was defined as greater than 42% FeNO reduction at short-term follow-up (typically 1-3 mo postbaseline). Biologic initiation and clinical outcomes were compared at short-term and long-term (typically 12 mo postbaseline) follow-up. RESULTS: Of 353 included patients, 257 (72.8%) completed the FeNOSuppT and 140 (54.5%) were positive. A positive FeNOSuppT was associated with greater improvements in the % predicted short-term forced expiratory volume in 1 second (FEV CONCLUSIONS: Delivering FeNOSuppT aligned with digital monitoring is feasible within routine care. A positive FeNOSuppT was associated with lower rates of biologic initiation, with similar clinical outcomes.
3. Cytomegalovirus reactivation in the lower respiratory tract as an independent risk factor for mortality in critically Ill patients.
In a 322‑patient ICU cohort with early bronchoscopy, LRT CMV reactivation was common (45%) and independently doubled the risk of ICU, in-hospital, 30‑day, and 90‑day mortality. Antiviral therapy showed potential benefit when radiology suggested CMV pneumonia, but signals of harm with bacterial co‑infection underscore the need for randomized trials and careful patient selection.
Impact: Links LRT CMV reactivation to mortality with nuanced therapeutic signals, informing diagnostics (bronchoscopy/PCR) and antiviral stewardship in the ICU.
Clinical Implications: Consider early LRT CMV PCR in deteriorating ICU patients; reserve antivirals for radiologically compatible CMV pneumonia and avoid routine use in bacterial co‑infection until RCT data are available.
Key Findings
- CMV reactivation in the LRT occurred in 45% (145/322) of ICU patients within 7 days of admission.
- Reactivation independently increased ICU (aSHR 2.28), in-hospital (aSHR 2.00), 30‑day (aSHR 2.11), and 90‑day mortality (aSHR 2.05).
- Antiviral therapy was associated with reduced ICU mortality when radiology suggested CMV pneumonia, but increased mortality with positive bacterial cultures (significant interactions).
Methodological Strengths
- Early standardized LRT sampling by bronchoscopy with quantitative PCR
- Competing‑risk adjusted multivariable Fine‑Gray modeling across multiple mortality endpoints
Limitations
- Single-center observational design with potential residual confounding and selection bias
- Non-randomized antiviral use; causality cannot be established
Future Directions: Conduct randomized trials testing antiviral therapy in LRT CMV‑positive ICU patients stratified by radiologic phenotype and co‑infection status; evaluate dynamic viral load thresholds for treatment initiation.
BACKGROUND: The clinical significance of cytomegalovirus reactivation in the lower respiratory tract (LRT) of critically ill patients remains unclear. We aimed to investigate the association between cytomegalovirus reactivation detected in LRT and intensive care unit (ICU) prognosis. METHODS: This study included critically ill patients admitted to a medical ICU at a tertiary referral center in South Korea between January 2021 and June 2023. Cytomegalovirus load in LRT samples collected via bronchoscopy was measured within 7 days of admission. Detection of cytomegalovirus DNA in LRT was defined as reactivation. Associations between cytomegalovirus reactivation and ICU, in-hospital, 30-day, and 90-day mortality were assessed using multivariable Fine-Gray model adjusted for major clinical factors. RESULTS: Of the 322 patients (median age 68 years, 66.8% male), 145 (45%) had cytomegalovirus reactivation in the LRT. Cytomegalovirus reactivation was independently associated with increased ICU (adjusted subdistribution hazard ratio [aSHR], 2.28; 95% confidence interval [CI], 1.46-3.56), in-hospital (aSHR, 2.00; 95% CI, 1.44-2.78), 30-day (aSHR, 2.11; 95% CI, 1.42-3.13), and 90-day mortality (aSHR, 2.05; 95% CI, 1.45-2.88). Anti-cytomegalovirus therapy was significantly associated with reduced ICU mortality in patients with radiologic findings suggestive of cytomegalovirus pneumonia (P for interaction = 0.001), but was linked to increased mortality in patients with positive bacterial cultures (P for interaction = 0.002). CONCLUSION: Cytomegalovirus reactivation in the LRT is associated with poor outcomes in critically ill patients. Anti-cytomegalovirus therapy was not associated with overall survival outcomes; however, the subgroup with radiologic findings of cytomegalovirus pneumonia suggested benefits, while the subgroup with bacterial co-infections suggested harmful effects. Randomized controlled trials are needed.