Daily Ards Research Analysis
An international Delphi consensus refines how ARDS should be defined across clinical, research, and educational contexts and prioritizes work on subphenotyping. A mechanistic cadaver study shows airway closure can miscalibrate esophageal pressure occlusion tests, supporting end-inspiratory occlusion as the operational standard. A clinician-focused review summarizes etiology, diagnosis, and multidisciplinary management for primary ciliary dyskinesia, an underdiagnosed cause of bronchiectasis.
Summary
An international Delphi consensus refines how ARDS should be defined across clinical, research, and educational contexts and prioritizes work on subphenotyping. A mechanistic cadaver study shows airway closure can miscalibrate esophageal pressure occlusion tests, supporting end-inspiratory occlusion as the operational standard. A clinician-focused review summarizes etiology, diagnosis, and multidisciplinary management for primary ciliary dyskinesia, an underdiagnosed cause of bronchiectasis.
Research Themes
- Refining ARDS definitions and subphenotyping
- Ventilatory monitoring: esophageal pressure calibration under airway closure
- Recognition and management of rare ciliopathies causing bronchiectasis
Selected Articles
1. Defining and subphenotyping ARDS: insights from an international Delphi expert panel.
Through a four-round, anonymous Delphi process across diverse ARDS experts, the panel reached consensus on a conceptual model and key components that should underpin ARDS definitions in clinical care, research, and education. The work highlights the need to incorporate subphenotyping to address ARDS heterogeneity and outlines research priorities and knowledge gaps.
Impact: Consensus on what constitutes ARDS and how subphenotypes should be considered can shape diagnostic criteria, trial design, and educational curricula. This positions the field for precision approaches in future studies and care pathways.
Clinical Implications: Adopting the agreed-upon definition components and considering subphenotypes can standardize ARDS diagnosis across centers and enable biomarker- and physiology-informed enrollment in clinical trials.
Key Findings
- Consensus was reached on a conceptual model and key components to include in ARDS definitions across clinical, research, and educational contexts.
- The panel agreed on the importance of subphenotyping to improve diagnostic precision and account for clinical and biological heterogeneity.
- A rigorous four-round, anonymous Delphi method with quantitative criteria mitigated peer pressure and group conformity.
- Knowledge gaps and research priorities were identified to guide future investigations.
Methodological Strengths
- Four-round anonymous Delphi with predefined quantitative consensus thresholds
- International, multidisciplinary expert participation
Limitations
- Expert consensus without primary patient-level data
- Generalizability depends on panel composition and requires empirical validation
Future Directions: Prospectively validate subphenotypes, integrate biomarkers and physiology into revised definitions, and evaluate impacts on trial efficiency and patient outcomes.
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. Erroneous calibration of esophageal pressure in case of airway closure.
In 12 human cadavers with airway closure, the ΔPaw/ΔPes ratio differed markedly at end-expiration versus end-inspiration when total PEEP was below AOP (0.42 vs 0.95; P<0.001) but not when PEEP exceeded AOP (~0.99 vs ~0.99; P=0.854). Findings, corroborated in two patients, indicate that airway closure underestimates ΔPaw/ΔPes and support performing the positive-pressure occlusion test at end-inspiration.
Impact: This mechanistic work identifies airway closure as a source of bias in esophageal balloon calibration, offering an immediately actionable change in procedure (end-inspiratory occlusion) to improve measurement reliability.
Clinical Implications: When using Pes to personalize ventilation (e.g., in ARDS, obesity, hydrostatic edema, CPR), perform occlusion calibration during end-inspiration and ensure total PEEP exceeds AOP to avoid underestimating ΔPaw/ΔPes; reconsider prior calibrations done below AOP.
Key Findings
- When total PEEP < AOP, ΔPaw/ΔPes at end-expiration vs end-inspiration diverged (0.42 vs 0.95; P<0.001).
- When total PEEP > AOP, ΔPaw/ΔPes was ~0.99 vs ~0.99 with no significant difference (P=0.854).
- Airway closure prevents full transmission of chest compression to airways, causing underestimation of ΔPaw/ΔPes below AOP.
- Two patient observations corroborated the cadaver findings and support an end-inspiratory occlusion calibration standard.
Methodological Strengths
- Controlled cadaveric experimental design with quantitative comparisons across PEEP levels
- Clinical corroboration in two patients
Limitations
- Cadaver model and small sample size limit generalizability
- No prospective clinical outcomes; only two patient observations
Future Directions: Prospectively validate end-inspiratory occlusion calibration, develop bedside methods to determine AOP, and test impact on ventilator settings and outcomes.
Airway closure results in a lack of communication between proximal and distal airways unless the airway pressure (Paw) overcomes the airway opening pressure (AOP). This has been described in patients undergoing mechanical ventilation with acute respiratory distress syndrome, obesity, hydrostatic pulmonary edema and during cardiopulmonary resuscitation. In these categories of patients, esophageal pressure (Pes) can guide the personalization of mechanical ventilation and calibration of the esophageal balloon is necessary to obtain reliable Pes measurements. The impact of airway closure has never been envisaged. This study investigated the impact of airway closure on the calibration of the esophageal balloon by the ∆Paw/∆Pes following a positive pressure occlusion test during passive mechanical ventilation. The calibration test was performed in twelve human cadavers with airway closure at end-expiration at different levels of positive end-expiratory pressure (PEEP) and at end-inspiration. The ∆Paw/∆Pes measured at end-expiration and at end-inspiration were significantly different when total PEEP was lower than AOP (estimated means 0.42 [0.40; 0.44] vs. 0.95 [0.92; 0.97], P < 0.001), while this difference was not observed when total PEEP was higher than AOP (estimated means 0.99 [0.92; 1.05] vs. 0.99 [0.92; 1.06], P = 0.854). These results were corroborated by observations during esophageal balloon calibration in two patients requiring Pes monitoring for clinical management. In case of airway closure, compression of the chest is not fully transmitted to the airways. This can lead to a conspicuous underestimation of the ∆Paw/∆Pes and poor reliability of this monitoring technique when the test takes place below AOP. Our results favor a positive pressure occlusion test performed during an end-inspiratory occlusion as the new standard of operative procedures for positioning and calibrating the esophageal balloon.
3. Primary ciliary dyskinesia: Aetiology, diagnosis and clinical management.
This clinician-oriented review summarizes the genetics and pathobiology of primary ciliary dyskinesia, typical early-life manifestations, and underrecognition in adults as a cause of bronchiectasis and subfertility. It outlines diagnostic approaches and multidisciplinary management strategies.
Impact: Raises awareness of a rare but important cause of bronchiectasis and subfertility, offering practical guidance on diagnosis and care pathways.
Clinical Implications: Consider PCD in adults with bronchiectasis, chronic sino-pulmonary symptoms, infertility, or laterality defects; refer for specialized diagnostics (e.g., nasal nitric oxide, high-speed video microscopy, genetic testing) and implement multidisciplinary management.
Key Findings
- PCD is a rare genetic disorder of motile cilia function with early-life respiratory manifestations and laterality defects.
- In adults, PCD remains underdiagnosed and is a cause of bronchiectasis and subfertility.
- The review synthesizes etiology, clinical presentation, diagnostic workup, and multidisciplinary management for clinicians.
Methodological Strengths
- Comprehensive, clinician-focused synthesis across etiology, diagnosis, and management
- Highlights gaps in adult recognition and pathways to specialized testing
Limitations
- Narrative review without systematic methodology or meta-analysis
- No new primary data; recommendations depend on existing literature quality
Future Directions: Develop standardized diagnostic algorithms and longitudinal cohorts to define outcomes and test targeted therapies for ciliopathies.
Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterised by abnormal function of motile cilia. The condition usually manifests in early life with neonatal distress, chronic sinopulmonary disease and organ laterality disorders. In adults, it is an underdiagnosed cause of bronchiectasis as well as subfertility. This review provides an overview of PCD for clinicians. We discuss its aetiology, its presentation, how it is diagnosed and its multidisciplinary clinical management.