Daily Ards Research Analysis
Analyzed 13 papers and selected 3 impactful papers.
Summary
Three impactful ARDS-related studies span implementation, advanced life support, and mechanism. A large multicenter registry from China quantifies ECMO mode escalation in ARDS and links it with higher mortality and center volume effects. A North American cohort shows pandemic-era gains in prone positioning were only partially sustained, while a mechanistic mouse study identifies S100A9–NRF2/HO-1 signaling as a modulator of neutrophil-driven acute lung injury.
Research Themes
- ECMO escalation and outcomes in ARDS
- Sustaining evidence-based ARDS therapies (prone positioning)
- Neutrophil-driven mechanisms and therapeutic targets in ALI/ARDS
Selected Articles
1. Prevalence, Risk Factors, and Mortality of Venovenous Extracorporeal Membrane Oxygenation Escalation in Acute Respiratory Distress Syndrome: A Multicenter Cohort Study From the Chinese Society of Extracorporeal Life Support Registry.
In a 112-center registry of 3333 ARDS patients on VV-ECMO, 4.7% required escalation to cardiocirculatory support (VA, VAV, or VVA). Escalation and lower center VV-ECMO volume independently correlated with higher in-hospital mortality (overall 47.9%). Among escalation modes, VA-ECMO was associated with higher survival versus VVA, whereas VAV was not.
Impact: Provides the largest contemporary estimate of VV-ECMO escalation in ARDS and quantifies its prognostic impact while highlighting center-volume effects and relative outcomes by escalation mode.
Clinical Implications: Centers should anticipate and prepare for cardiogenic shock during VV-ECMO in ARDS; referral to higher-volume centers may reduce escalation and mortality risk. When escalation is required, VA-ECMO may confer better survival than VVA, informing mode selection.
Key Findings
- 4.7% (157/3333) of VV-ECMO ARDS patients underwent escalation to VA (n=41), VAV (n=68), or VVA (n=48).
- Escalation and lower hospital VV-ECMO volume were independently associated with higher in-hospital mortality (overall mortality 47.9%).
- Hospitals with >15 VV-ECMO cases/year had lower odds of escalation compared to <6/year (OR 0.596; 95% CI 0.382–0.930).
- Among escalated patients, VA-ECMO was associated with higher survival than VVA (OR 3.444; 95% CI 1.046–11.342); VAV was not significantly different.
Methodological Strengths
- Large, nationwide multicenter registry (112 centers) with contemporary practice capture (2017–2023).
- Multivariable modeling adjusting for center volume and clinical factors; explicit reporting of effect sizes with CIs.
Limitations
- Observational design with potential residual confounding and selection bias for escalation decisions.
- Voluntary registry may have variable data completeness; lack of granular hemodynamic indications and timing for escalation.
Future Directions: Prospective multicenter studies with standardized criteria for escalation and mode selection; evaluation of regionalization strategies and their impact on outcomes.
OBJECTIVES: Patients with acute respiratory distress syndrome (ARDS) undergoing venovenous extracorporeal membrane oxygenation (ECMO) may experience severe cardiogenic shock, necessitating ECMO mode "escalation" for cardiopulmonary co-support. There is a paucity of data regarding the prevalence, risk factors, and mortality of venovenous ECMO escalation. We aimed to conduct a large study to address this issue. DESIGN: A multicenter cohort study. SETTING: The analysis was conducted based on data from the Chinese Society of Extracorporeal Life Support registry, a nationwide voluntary platform capturing clinical information of patients receiving ECMO support. Data were collected from 112 centers across China between January 2017 and December 2023. PATIENTS: Eligible participants included adult patients with ARDS receiving venovenous ECMO, excluding pregnant patients and those with missing data on escalation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was in-hospital mortality. Of the 3333 patients on venovenous ECMO, 157 (4.7%) underwent escalation to venoarterial ECMO (n = 41), veno-arterial-venous (VAV) ECMO (n = 68), and veno-veno-arterial (VVA) ECMO (n = 48). Several characteristics, including hospital's annual venovenous ECMO volume (hospitals > 15 cases per year vs. those < 6 cases per year; odds ratio [OR], 0.596; 95% CI, 0.382-0.930), were associated with the occurrence of escalation. The overall in-hospital mortality was 47.9%. Both escalation and lower hospital's venovenous ECMO volume were independently associated with an increased mortality. Compared with patients escalated to VVA ECMO, those escalated to venoarterial ECMO had a significantly higher survival rate (OR, 3.444; 95% CI, 1.046-11.342), whereas those escalated to VAV ECMO did not. CONCLUSIONS: In this study, 4.7% of ARDS patients with venovenous ECMO underwent a mode escalation. Escalation was independently associated with higher in-hospital mortality, an association that may be partially confounded by low hospital's venovenous ECMO volume. Among the modes after escalation, venoarterial ECMO was associated with a significantly higher survival rate. These findings require validation by further prospective multicenter studies to guide decision-making for ARDS patients requiring ECMO support.
2. Prone Positioning in a North American Cohort of Hypoxemic Patients on Mechanical Ventilation.
Across 37 North American hospitals, proning among 5944 eligible hypoxemic, ventilated adults rose sharply during the pandemic (51.9%) but fell post-pandemic (25.6%) relative to pre-pandemic (11.0%). Adjusted odds of proning were 7.6 times higher during the pandemic versus pre-pandemic, with persistent hospital-level variability. SARS-CoV-2–positive cases were more likely to be proned than negative cases.
Impact: Quantifies real-world adoption and durability of a guideline-recommended, mortality-reducing ARDS intervention and exposes persistent inter-hospital variability amenable to implementation strategies.
Clinical Implications: Quality improvement should target sustaining early proning in eligible ARDS with standardized protocols, auditing, and feedback, while reducing unwarranted inter-hospital variation.
Key Findings
- Among 5944 proning-eligible patients, overall proning use was 36.2%: 11.0% pre-pandemic, 51.9% during pandemic, and 25.6% post-pandemic.
- Adjusted odds of proning were higher during the pandemic versus pre-pandemic (OR 7.6; 95% CI 5.5–10.4) and versus post-pandemic (OR 2.7; 95% CI 1.8–3.9).
- Substantial hospital-level variation persisted (median ORs: pre 2.9, pandemic 1.9, post 2.3), and SARS-CoV-2 positivity increased proning use (OR 5.1; 95% CI 4.1–5.6).
Methodological Strengths
- Large multicenter cohort with clear, physiologic eligibility criteria and time-anchored exposure definition.
- Hierarchical modeling quantifying hospital-level variation (median OR) with robust adjustment.
Limitations
- Retrospective design susceptible to unmeasured confounding and indication bias.
- Cannot infer effect on patient outcomes; lacks details on proning duration, contraindications, and staffing/resources.
Future Directions: Implementation trials and sustained QI bundles to normalize early proning, with real-time dashboards and staffing support to reduce inter-hospital variability.
OBJECTIVES: Despite historically limited adoption of prone positioning, a potentially life-saving guideline-recommended intervention for moderate-severe acute respiratory distress syndrome, its use increased for mechanically ventilated patients during the COVID-19 pandemic. Whether implementation of this guideline-recommended intervention was sustained is unknown. Thus, we aimed to evaluate peri-pandemic trends in proning use. DESIGN: We conducted a retrospective cohort study of proning use among mechanically ventilated adults compared across pre-pandemic (from January 2018 to February 2020), pandemic (from March 2020 to February 2022), and post-pandemic (from March 2022 to December 2024) periods. SETTING: Thirty-seven North American hospitals. PATIENTS: Mechanically ventilated patients with persistent moderate-to-severe hypoxemia (Pao2/Fio2 ≤ 150 mm Hg, Fio2 ≥ 0.6, and positive end-expiratory pressure ≥ 5 cm H2O). INTERVENTIONS: Proning within 12 hours of meeting hypoxemia criteria. MEASUREMENTS AND MAIN RESULTS: Among 5944 proning-eligible patients, 2155 (36.2%) received proning: 11.0% pre-pandemic, 51.9% pandemic, and 25.6% post-pandemic. The adjusted odds ratio (OR) for proning during the pandemic vs. pre-pandemic periods was 7.6 (95% CI, 5.5-10.4), and during the pandemic vs. post-pandemic periods was 2.7 (95% CI, 1.8-3.9). Proning varied widely by hospital and was quantified with median ORs (median change in odds of proning for similar patients admitted at a lower vs. higher proning hospital) of 2.9 (95% credible interval [CrI], 1.9-5.3) pre-pandemic, 1.9 (95% CrI, 1.6-2.3) pandemic, and 2.3 (95% CrI, 1.8-3.3) post-pandemic. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive vs. negative pandemic-period patients had increased proning use (OR, 5.1; 95% CI, 4.1-5.6), as did pandemic-period patients without SARS-CoV-2 compared with pre-pandemic patients (OR, 3.8; 95% CI, 2.7-5.2). The difference in proning use between pandemic SARS-CoV-2 negative and post-pandemic patients was smaller and not significant (OR, 1.3; 95% CI, 0.9-1.8). CONCLUSIONS: In a North American cohort of proning-eligible patients, proning increased during the pandemic and then declined. Interventions that improve and sustain implementation of this guideline-recommended intervention are needed.
3. S100A9 deletion ameliorates acute lung injury by attenuating excessive neutrophil activation via activating the NRF2/HO-1 signaling axis.
In LPS-induced ALI, S100A9 knockout mice exhibited reduced lung injury, edema, inflammatory infiltration, and improved survival. Mechanistically, S100A9 deletion activated NRF2/HO-1 signaling, suppressing neutrophil activation and NET formation; primary neutrophils from KO mice showed attenuated activation and enhanced antioxidant capacity.
Impact: Identifies a neutrophil-centered pathway (S100A9–NRF2/HO-1) modulating ALI severity, suggesting testable therapeutic strategies targeting S100A9 or enhancing NRF2 signaling.
Clinical Implications: While preclinical, the data support exploration of S100A9 inhibitors, NRF2 activators, or anti-NET approaches as adjuncts to lung-protective ventilation in ALI/ARDS.
Key Findings
- S100A9 knockout reduced LPS-induced lung injury, edema, inflammatory infiltration, and improved survival in mice.
- Activation of NRF2/HO-1 signaling accompanied suppression of neutrophil activation and decreased NET formation.
- Primary bone marrow-derived neutrophils from KO mice showed reduced activation and enhanced antioxidant capacity upon LPS exposure.
Methodological Strengths
- Use of genetic knockout with in vivo and in vitro validation across multiple readouts (histology, edema, oxidative stress, NETs, survival).
- Mechanistic linkage to NRF2/HO-1 pathway strengthens biological plausibility.
Limitations
- Single-hit LPS model may not capture the full heterogeneity of human ARDS; translational generalizability is uncertain.
- Abstract lacks sample size details and pharmacologic inhibition data to support therapeutic tractability.
Future Directions: Test pharmacologic S100A9 inhibitors and NRF2 activators in diverse ALI/ARDS models and large animals; integrate human biomarker studies to assess target engagement and translatability.
BACKGROUND: Acute lung injury (ALI) is a complex and life-threatening condition. In severe cases, ALI can progress to acute respiratory distress syndrome (ARDS), which is associated with high mortality. It is characterized by diffuse pulmonary parenchymal inflammation and refractory hypoxemia. Neutrophils, as pivotal immune cells in the lungs, play a critical role in the development and progression of ALI. This study aimed to determine whether S100A9 deletion alleviates LPS-induced ALI by modulating neutrophil activation through the NRF2/HO-1 signaling axis. METHODS: We established an ALI model using LPS in both wild-type (WT) and S100A9 gene knockout (KO) mice to assess pulmonary inflammation and oxidative stress. Lung injury severity, inflammation, oxidative stress status, neutrophil accumulation, and NET formation were evaluated in vivo, and bone marrow-derived primary neutrophils were exposed to LPS in vitro to examine their activation characteristics and antioxidant capacity. RESULTS: S100A9 KO significantly ameliorated lung tissue injury, edema, and inflammatory cell infiltration, and improved mouse survival rates. Mechanistically, S100A9 knockout alleviates acute lung injury by activating the NRF2 signaling pathway, which in turn downregulates neutrophil activation and the production of NETs. CONCLUSION: Our findings indicate that S100A9 deletion attenuates neutrophil activation and oxidative stress and may alleviate LPS-induced ALI through activation of the NRF2/HO-1 signaling pathway.