Evolving outcomes of extracorporeal membrane oxygenation support for severe COVID-19 ARDS in Sorbonne hospitals, Paris.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) was frequently used to treat patients with severe coronavirus disease-2019 (COVID-19)-associated acute respiratory distress (ARDS) during the initial outbreak. Care of COVID-19 patients evolved markedly during the second part of 2020. Our objective was to compare the characteristics and outcomes of patients who received ECMO for severe COVID-19 ARDS before or after July 1, 2020. METHODS: We included consecutive adults diagnosed with COVID-19 in Paris-Sorbonne University Hospital Network ICUs, who received ECMO for severe ARDS until January 28, 2021. Characteristics and survival probabilities over time were estimated during the first and second waves. Pre-ECMO risk factors predicting 90-day mortality were assessed using multivariate Cox regression. RESULTS: Characteristics of the 88 and 71 patients admitted, respectively, before and after July 1, 2020, were comparable except for older age, more frequent use of dexamethasone (18% vs. 82%), high-flow nasal oxygenation (19% vs. 82%) and/or non-invasive ventilation (7% vs. 37%) after July 1. Respective estimated probabilities (95% confidence intervals) of 90-day mortality were 36% (27-47%) and 48% (37-60%) during the first and the second periods. After adjusting for confounders, probability of 90-day mortality was significantly higher for patients treated after July 1 (HR 2.27, 95% CI 1.02-5.07). ECMO-related complications did not differ between study periods. CONCLUSIONS: 90-day mortality of ECMO-supported COVID-19-ARDS patients increased significantly after July 1, 2020, and was no longer comparable to that of non-COVID ECMO-treated patients. Failure of prolonged non-invasive oxygenation strategies before intubation and increased lung damage may partly explain this outcome.

Role and Applications of Experimental Animal Models of Fontan Circulation.

Over the last four decades, the Fontan operation has been the treatment of choice for children born with complex congenital heart diseases and a single-ventricle physiology. However, therapeutic options remain limited and despite ongoing improvements in initial surgical repair, patients still experience a multiplicity of cardiovascular complications. The causes for cardiovascular failure are multifactorial and include systemic ventricular dysfunction, pulmonary vascular resistance, atrioventricular valve regurgitation, arrhythmia, development of collaterals, protein-losing enteropathy, hepatic dysfunction, and plastic bronchitis, among others. The mechanisms leading to these late complications remain to be fully elucidated. Experimental animal models have been developed as preclinical steps that enable a better understanding of the underlying pathophysiology. They furthermore play a key role in the evaluation of the efficacy and safety of new medical devices prior to their use in human clinical studies. However, these experimental models have several limitations. In this review, we aim to provide an overview of the evolution and progress of the various types of experimental animal models used in the Fontan procedure published to date in the literature. A special focus is placed on experimental studies performed on animal models of the Fontan procedure with or without mechanical circulatory support as well as a description of their impact in the evolution of the Fontan design. We also highlight the contribution of animal models to our understanding of the pathophysiology and assess forthcoming developments that may improve the contribution of animal models for the testing of new therapeutic solutions.

Survival and Long-Term Functional Status of COVID-19 Patients Requiring Prolonged Extracorporeal Membrane Oxygenation Support.

Rationale: Severe cases of acute respiratory distress syndrome (ARDS) may require prolonged (>28 d) extracorporeal membrane oxygenation (ECMO). In nonresolving disease, recovery is uncertain, and lung transplant may be proposed. Objectives: This study aims to identify the variables influencing survival and to describe the functional status of these patients at 6 months. Methods: This was a retrospective, multicenter, observational cohort study including patients requiring ECMO support for coronavirus disease (COVID-19)-related ARDS for >28 days. Multivariate analysis was performed using Cox regression in preselected variables and in least absolute shrinkage and selection operator selected variables. In a post hoc analysis to account for confounders and differences in awake strategy use by centers, treatment effects of the awake strategy were estimated using an augmented inverse probability weighting estimator with robust standard errors clustered by center. Results: Between March 15, 2020 and March 15, 2021, 120 patients required ECMO for >28 days. Sixty-four patients (53.3%) survived decannulation, 62 (51.7%) were alive at hospital discharge, and 61 (50.8%) were alive at 6-month follow-up. In the multivariate analysis, age (1.09; 95% confidence interval [CI], 1.03-1.15; P = 0.002) and an awake ECMO strategy (defined as the patient being awake, cooperative, and performing rehabilitation and physiotherapy with or without invasive mechanical ventilation at any time during the extracorporeal support) (0.14; 95% CI, 0.03-0.47; P = 0.003) were found to be predictors of hospital survival. At 6 months, 51 (42.5%) patients were at home, 42 (84.3%) of them without oxygen therapy. A cutoff point of 47 ECMO days had a 100% (95% CI, 76.8-100%) sensitivity and 60% (95% CI, 44.3-73.6%) specificity for oxygen therapy at 6 months, with 100% specificity being found in 97 days. Conclusions: Patients with COVID-19 who require ECMO for >28 days can survive with nonlimiting lung impairment. Age and an awake ECMO strategy may be associated with survival. Longer duration of support correlates with need for oxygen therapy at 6 months.

Comparative outcomes of extracorporeal membrane oxygenation for COVID-19 delivered in experienced European centres during successive SARS-CoV-2 variant outbreaks (ECMO-SURGES): an international, multicentre, retrospective cohort study.

BACKGROUND: To inform future research and practice, we aimed to investigate the outcomes of patients who received extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome (ARDS) due to different variants of SARS-CoV-2. METHODS: This retrospective study included consecutive adult patients with laboratory-confirmed SARS-CoV-2 infection who received ECMO for ARDS in 21 experienced ECMO centres in eight European countries (Austria, Belgium, England, France, Germany, Italy, Portugal, and Spain) between Jan 1, 2020, and Sept 30, 2021. We collected data on patient characteristics, clinical status, and management before and after the initiation of ECMO. Participants were grouped according to SARS-CoV-2 variant (wild type, alpha, delta, or other) and period of the pandemic (first [Jan 1-June 30] and second [July 1-Dec 31] semesters of 2020, and first [Jan 1-June 30] and second [July 1-Sept 30] semesters of 2021). Descriptive statistics and Kaplan-Meier survival curves were used to analyse evolving characteristics, management, and patient outcomes over the first 2 years of the pandemic, and independent risk factors of mortality were determined using multivariable Cox regression models. The primary outcome was mortality 90 days after the initiation of ECMO, with follow-up to Dec 30, 2021. FINDINGS: ECMO was initiated in 1345 patients. Patient characteristics and management were similar for the groups of patients infected with different variants, except that those with the delta variant had a younger median age and less hypertension and diabetes. 90-day mortality was 42% (569 of 1345 patients died) overall, and 43% (297/686) in patients infected with wild-type SARS-CoV-2, 39% (152/391) in those with the alpha variant, 40% (78/195) in those with the delta variant, and 58% (42/73) in patients infected with other variants (mainly beta and gamma). Mortality was 10% higher (50%) in the second semester of 2020, when the wild-type variant was still prevailing, than in other semesters (40%). Independent predictors of mortality were age, immunocompromised status, a longer time from intensive care unit admission to intubation, need for renal replacement therapy, and higher Sequential Organ Failure Assessment haemodynamic component score, partial pressure of arterial carbon dioxide, and lactate concentration before ECMO. After adjusting for these variables, mortality was significantly higher with the delta variant than with the other variants, the wild-type strain being the reference. INTERPRETATION: Although crude mortality did not differ between variants, adjusted risk of death was highest for patients treated with ECMO infected with the delta variant of SARS-CoV-2. The higher virulence and poorer outcomes associated with the delta strain might relate to higher viral load and increased inflammatory response syndrome in infected patients, reinforcing the need for a higher rate of vaccination in the population and updated selection criteria for ECMO, should a new and highly virulent strain of SARS-CoV-2 emerge in the future. Mortality was noticeably lower than in other large, multicentre series of patients who received ECMO for COVID-19, highlighting the need to concentrate resources at experienced centres. FUNDING: None.