Daily Respiratory Research Analysis
Three high-impact respiratory studies stood out today: a multinational prospective cohort of 3,860 ECMO-supported COVID-19 patients clarifies mortality predictors and 6-month outcomes; interim U.S. estimates show the 2024–2025 influenza vaccines substantially reduce medically attended flu and hospitalizations; and a multicenter analysis in immunocompromised acute hypoxemic respiratory failure identifies distinct oxygenation-response trajectories that strongly predict intubation and mortality.
Summary
Three high-impact respiratory studies stood out today: a multinational prospective cohort of 3,860 ECMO-supported COVID-19 patients clarifies mortality predictors and 6-month outcomes; interim U.S. estimates show the 2024–2025 influenza vaccines substantially reduce medically attended flu and hospitalizations; and a multicenter analysis in immunocompromised acute hypoxemic respiratory failure identifies distinct oxygenation-response trajectories that strongly predict intubation and mortality.
Research Themes
- Outcomes and prognostication in ECMO for severe respiratory failure
- Real-world vaccine effectiveness for seasonal influenza
- Data-driven personalization of oxygenation strategies in immunocompromised ARF
Selected Articles
1. In-hospital outcomes and 6-month follow-up results of patients supported with extracorporeal membrane oxygenation for COVID-19 from the second wave to the end of the pandemic (EuroECMO-COVID): a prospective, international, multicentre, observational study.
In a 98-center, 21-country prospective cohort (n=3,860) of COVID-19 patients supported with ECMO, in-hospital mortality was 55.9% and largely occurred during ECMO. Older age, pre-ECMO renal failure and vasopressor use, delayed cannulation, and major complications predicted mortality, whereas 99.7% of in-hospital survivors were alive at 6 months despite persistent dyspnea and some cardiac/neurocognitive symptoms.
Impact: This is the largest prospective, multinational ECMO cohort across later pandemic waves, refining risk stratification and underscoring the need for structured post-ECMO follow-up.
Clinical Implications: Use identified predictors (age, pre-ECMO organ failure/vasopressors, cannulation delay, severe complications) for selection, timing, and risk communication; establish multidisciplinary post-ECMO clinics to address persistent dyspnea and neurocognitive/cardiac sequelae.
Key Findings
- In-hospital mortality was 55.9% (2,158/3,860), with 81.2% of deaths occurring during ECMO support.
- Mortality was associated with older age, pre-ECMO renal failure and vasopressor use, longer intubation-to-ECMO interval, and complications (neurologic events, sepsis, bowel ischemia, renal failure, bleeding).
- Of in-hospital survivors (n=1,702), 99.7% were alive at 6 months; persistent symptoms included dyspnea (32%), cardiac (7.8%), and neurocognitive (10.7%) complaints.
Methodological Strengths
- Prospective, multinational, multicenter design with large sample size (n=3,860) across 98 centers in 21 countries
- Adjusted mixed-effects logistic regression identifying independent mortality predictors with external generalizability
Limitations
- Observational design without randomization; residual confounding likely
- Temporal and center-level practice variability across pandemic waves may influence outcomes
Future Directions: Develop validated prognostic tools incorporating timing and complication risks; evaluate standardized cannulation timing strategies and structured post-ECMO rehabilitation to reduce morbidity.
BACKGROUND: Extracorporeal membrane oxygenation (ECMO) for COVID-19 was thoroughly assessed during the first pandemic wave, but data on subsequent waves are limited. We aimed to investigate in-hospital and 6-month survival of patients with COVID-19 supported with ECMO from the second pandemic wave (Sept 15, 2020) until the end of the pandemic (March 21, 2023, announced by WHO). METHODS: EuroECMO-COVID is a prospective, observational study including adults (aged ≥16 years) requiring ECMO respiratory support for COVID-19 from 98 centres in 21 countries. We compared patient characteristics and outcomes between in-hospital survivors and non-survivors. Mixed-effects multivariable logistic regressions were used to investigate factors linked to in-hospital mortality. 6-month survival and overall patient status were determined via patient contact or chart review. This study is registered with ClinicalTrials.gov, NCT04366921, and is complete. FINDINGS: We included 3860 patients (2687 [69·7%] were male and 1169 [30·3%] were female; median age 51 years [SD 11]) from 98 centres in 21 countries. In-hospital mortality was 55·9% (n=2158), with 81·2% (n=1752) deaths occurring during ECMO support. More non-survivors had diabetes, hypertension, cardiovascular disease, and renal failure, and required more pre-ECMO inotropes and vasopressors compared with survivors. Median support duration was 18 days (IQR 10-31) for both groups. Factors linked to in-hospital mortality included older age, pre-ECMO renal failure, pre-ECMO vasopressors use, longer time from intubation to ECMO initiation, and complications, including neurological events, sepsis, bowel ischaemia, renal failure, and bleeding. Of the 1702 (44·1%) in-hospital survivors, 99·7% (n=1697) were alive at 6 months follow-up. Many patients at 6 months follow-up had dyspnoea (501 [32·0%] of 1568 patients), cardiac (122 [7·8%] of 1568 patients), or neurocognitive (168 [10·7%] of 1567 patients) symptoms. INTERPRETATION: Our data for patients undergoing ECMO support for respiratory distress from the second COVID-19 wave onwards confirmed most findings from the first wave regarding patient characteristics and factors correlated to in-hospital mortality. Nevertheless, in-hospital mortality was higher than during the initial pandemic wave while 6-month post-discharge survival remained favourable (99·7%). Persisting post-discharge symptoms confirmed the need for post-ECMO patient follow-up programmes. FUNDING: None.
2. Interim Estimates of 2024-2025 Seasonal Influenza Vaccine Effectiveness - Four Vaccine Effectiveness Networks, United States, October 2024-February 2025.
Across four U.S. networks during Oct 2024–Feb 2025, the influenza vaccine reduced medically attended influenza and hospitalizations, with outpatient VE of ~32%–60% in children and 36%–54% in adults, and hospitalization VE of ~63%–78% in children and 41%–55% in adults.
Impact: Timely, multi-network real-world VE estimates inform clinical and public health decisions mid-season, including prioritization and messaging for vaccination.
Clinical Implications: Reinforce age-appropriate influenza vaccination for all eligible persons ≥6 months; communicate that current-season vaccines meaningfully reduce medically attended influenza and hospitalization risk.
Key Findings
- Outpatient VE against any influenza: 32%, 59%, and 60% in children/adolescents across three networks; 36% and 54% in adults across two networks.
- VE against influenza-associated hospitalization: 63% and 78% in children/adolescents; 41% and 55% in adults in two networks.
- Findings support continued seasonal vaccination while influenza viruses circulate locally.
Methodological Strengths
- Multi-network, real-world interim analysis covering outpatient and hospitalization settings
- Age-stratified VE estimates across diverse clinical networks enhancing generalizability
Limitations
- Interim estimates may change as season progresses and circulating strains shift
- Potential residual confounding and differences in testing/healthcare-seeking across networks
Future Directions: Finalize end-of-season VE, subtype-specific effectiveness, and assess waning to guide booster timing and vaccine composition.
Annual influenza vaccination is recommended for all persons aged ≥6 months in the United States. Interim influenza vaccine effectiveness (VE) was calculated among patients with acute respiratory illness-associated outpatient visits and hospitalizations from four VE networks during the 2024-25 influenza season (October 2024-February 2025). Among children and adolescents aged <18 years, VE against any influenza was 32%, 59%, and 60% in the outpatient setting in three networks, and against influenza-associated hospitalization was 63% and 78% in two networks. Among adults aged ≥18 years, VE in the outpatient setting was 36% and 54% in two networks and was 41% and 55% against hospitalization in two networks. Preliminary estimates indicate that receipt of the 2024-2025 influenza vaccine reduced the likelihood of medically attended influenza and influenza-associated hospitalization. CDC recommends annual receipt of an age-appropriate influenza vaccine by all eligible persons aged ≥6 months as long as influenza viruses continue to circulate locally.
3. Escalation of Oxygenation Modalities and Mortality in Critically Ill Immunocompromised Patient With Acute Hypoxemic Respiratory Failure: A Clustering Analysis of a Prospectively Multicenter, Multinational Dataset.
In 1,547 immunocompromised ICU patients with acute hypoxemic respiratory failure, longitudinal clustering of oxygenation modality changes identified three distinct trajectories that strongly predicted invasive ventilation needs and mortality, with one cluster showing extremely high ICU mortality.
Impact: Introduces a data-driven, longitudinal phenotyping of oxygenation responses that may enable early risk stratification and escalation decisions in a vulnerable population.
Clinical Implications: Embedding trajectory-based monitoring can help recognize high-risk patterns early, prompting earlier intubation or adjunctive therapies, and tailoring escalation protocols for immunocompromised patients.
Key Findings
- Three longitudinal clusters of oxygenation strategy changes were identified (A, B, C) with markedly different outcomes.
- Cluster B had 32.9% invasive ventilation requirement and 97% ICU mortality; Cluster C had 37.5% invasive ventilation but only 0.3% ICU mortality.
- Clusters B and C were independently associated with invasive mechanical ventilation after adjustment (OR 9.87 and 19.8).
Methodological Strengths
- Prospective multinational source cohort with large sample size (EFRAIM) and standardized data collection
- Use of nonparametric longitudinal clustering to capture dynamic treatment-response phenotypes
Limitations
- Post hoc analysis without external validation; risk of overfitting
- Potential unmeasured confounding and heterogeneity in oxygenation strategies across centers
Future Directions: Prospective validation of cluster assignment at the bedside, integration into early warning systems, and testing cluster-guided escalation strategies in interventional trials.
OBJECTIVES: Acute hypoxemic respiratory failure in immunocompromised patients remains the leading cause of admission to the ICU, with high case fatality. The response to the initial oxygenation strategy may be predictive of outcome. This study aims to assess the response to the evolutionary profiles of oxygenation strategy and the association with survival. DESIGN: Post hoc analysis of EFRAIM study with a nonparametric longitudinal clustering technique (longitudinal K-mean). SETTING AND PATIENTS: Multinational, observational prospective cohort study performed in critically ill immunocompromised patients admitted for an acute respiratory failure. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 1547 patients who did not require invasive mechanical ventilation (iMV) at ICU admission were included. Change in ventilatory support was assessed and three clusters of change in oxygenation modality over time were identified. Cluster A: 12.3% iMV requirement and high survival rate, n = 717 patients (46.3%); cluster B: 32.9% need for iMV, 97% ICU mortality, n = 499 patients (32.3%); and cluster C: 37.5% need for iMV, 0.3% ICU mortality, n = 331 patients (21.4%). These clusters demonstrated a high discrimination. After adjustment for confounders, clusters B and C were independently associated with need for iMV (odds ratio [OR], 9.87; 95% CI, 7.26-13.50 and OR, 19.8; 95% CI, 13.7-29.1). CONCLUSIONS: This study identified three distinct highly performing clusters of response to initial oxygenation strategy, which reliably predicted the need for iMV requirement and hospital mortality.