Extracorporeal Membrane Oxygenation for COVID-19: A Systematic Review

High-Performance Polyolefin Material: Synthesis, Properties, and Application of Poly(4-Methyl-1-pentene)

As a kind of high-performance thermoplastic crystalline resin, poly(4-methyl-1-pentene) (PMP) is characterized by its low density, low dielectric constant, exceptional mechanical and chemical properties, high transparency, and gas permeability. PMP has recently received more attention since COVID-19, because it is used as a hollow-fiber membrane for extracorporeal membrane oxygenation (ECMO) based on its high permeability and excellent biocompatibility. This review summarizes the chemical structure, synthesis, properties, and application of PMP. The advancements in catalyst systems for the catalytic synthesis of PMP, including Ziegler-Natta, metallocene, post-metallocene, and late-transition metal catalysts are emphasized. Furthermore, the molecular chain structure, helical conformation, and crystallization morphology of PMP, as well as its properties and applications, are also introduced in detail. Additionally, PMP composites and functional PMP materials are also described as promising and high-performance materials.

A phase 1/2 clinical trial of invariant natural killer T cell therapy in moderate-severe acute respiratory distress syndrome

Invariant natural killer T (iNKT) cells, a unique T cell population, lend themselves for use as adoptive therapy due to diverse roles in orchestrating immune responses. Originally developed for use in cancer, agenT-797 is a donor-unrestricted allogeneic ex vivo expanded iNKT cell therapy. We conducted an open-label study in virally induced acute respiratory distress syndrome (ARDS) caused by the severe acute respiratory syndrome-2 virus (trial registration NCT04582201). Here we show that agenT-797 rescues exhausted T cells and rapidly activates both innate and adaptive immunity. In 21 ventilated patients including 5 individuals receiving veno-venous extracorporeal membrane oxygenation (VV-ECMO), there are no dose-limiting toxicities. We observe an anti-inflammatory systemic cytokine response and infused iNKT cells are persistent during follow-up, inducing only transient donor-specific antibodies. Clinical signals of associated survival and prevention of secondary infections are evident. Cellular therapy using off-the-shelf iNKT cells is safe, can be rapidly scaled and is associated with an anti-inflammatory response. The safety and therapeutic potential of iNKT cells across diseases including infections and cancer, warrants randomized-controlled trials.

Clinical Outcome Comparison of Patients Requiring Extracorporeal Membrane Oxygenation With or Without COVID-19 Infection

In severe COVID-19-related respiratory failure, extracorporeal membrane oxygenation (ECMO) is a useful modality that is used to provide effective oxygenation and ventilation to the patient. This descriptive study aimed to investigate and compare the outcomes between COVID-19-infected patients and patients who were not infected and required ECMO support. A retrospective study was undertaken on a cohort of 82 adult patients ([Formula: see text]18-year-old) who required venoarterial (VA-ECMO) and venovenous (VV-ECMO) ECMO between January 2019 and December 2022 in a single academic center. Patients who were cannulated for COVID-19-related respiratory failure (C-group) were compared to patients who were cannulated for non-COVID etiologies (non-group). Patients were excluded if data were missing regarding cannulation, decannulation, presenting diagnosis, and survival status. Categorical data were reported as counts and percentages, and continuous data were reported as means with 95% confidence intervals. Out of the 82 included ECMO patients, 33 (40.2%) were cannulated for COVID-related reasons, and 49 (59.8%) were cannulated for reasons other than COVID-19 infection. Compared to the non-group, the C-group had a higher in-hospital (75.8% vs. 55.1%) and overall mortality rate (78.8% vs. 61.2%). The C-group also had an average hospital length of stay (LOS) of 46.6 ± 13.2 days and an average intensive care unit (ICU) LOS of 44.1 ± 13.3 days. The non-group had an average hospital LOS of 24.8 ± 6.6 days and an average ICU LOS of 20.8 ± 5.9 days. Subgroup analysis of patients only treated with VV-ECMO yielded a greater in-hospital mortality rate for the C-group compared to the non-group (75.0% vs. 42.1%). COVID-19-infected patients may experience different morbidity and mortality rates as well as clinical presentations compared to non-COVID-infected patients when requiring ECMO support.

One hundred ECMO retrivals before and during the Covid-19 pandemic: an observational study

OBJECTIVES

Patients with severe acute respiratory distress syndrome may require veno-venous extracorporeal membrane oxygenation (V-V ECMO) support. For patients in peripheral hospitals, retrieval by mobile ECMO teams and transport to high-volume centers is associated with improved outcomes, including the recent COVID-19 pandemic. To enable a safe transport of patients, a specialised ECMO-retrieval program needs to be implemented. However, there is insufficient evidence on how to safely and efficiently perform ECMO retrievals. We report single-centre data from out-of-centre initiations of VV-ECMO before and during the COVID-19 pandemic.

DESIGN & SETTING

Single-centre retrospective study. We include all the retrievals performed by our ECMO centre between January 1st, 2014, and April 30th, 2021.

RESULTS

One hundred ECMO missions were performed in the study period, for a median retrieval volume of 13 (IQR: 9-16) missions per year. the cause of the acute respiratory distress syndrome was COVID-19 in 10 patients (10 %). 98 (98 %) patients were retrieved and transported to our ECMO centre. To allow safe transport, 91 of them were cannulated on-site and transported on V-V ECMO. The remaining seven patients were centralised without ECMO, but they were all connected to V-V ECMO in the first 24 hours. No complications occurred during patient transport. The median duration of the ECMO mission was 7 hours (IQR: 6-9, range: 2 - 17). Median duration of ECMO support was 14 days (IQR: 9-24), whereas the ICU stay was 24 days (IQR:18-44). Overall, 73 patients were alive at hospital discharge (74 %). Survival rate was similar in non-COVID-19 and COVID-19 group (73 % vs 80 %, p = 0.549).

CONCLUSION

In this single-centre experience, before and during COVID-19 era, retrieval and ground transportation of ECMO patients was feasible and was not associated with complications. Key factors of an ECMO retrieval program include a careful selection of the transport ambulance, training of a dedicated ECMO mobile team and preparation of specific checklists and standard operating procedures.