Electron Microscopic Confirmation of Anisotropic Pore Characteristics for ECMO Membranes Theoretically Validating the Risk of SARS-CoV-2 Permeation.

Makoto Fukuda,Kazunori Sadano,Asako Tokumine,Kiyotaka Sakai,Hitoshi Saomoto,Tomohiro Mori,Tomoya Furuya

doi:10.3390/membranes11070529

Makoto Fukuda, Kazunori Sadano + Show 5 more

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https://doi.org/10.3390/membranes11070529

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Abstract

The objective of this study is to clarify the pore structure of ECMO membranes by using our approach and theoretically validate the risk of SARS-CoV-2 permeation. There has not been any direct evidence for SARS-CoV-2 leakage through the membrane in ECMO support for critically ill COVID-19 patients. The precise pore structure of recent membranes was elucidated by direct microscopic observation for the first time. The three types of membranes, polypropylene, polypropylene coated with thin silicone layer, and polymethylpentene (PMP), have unique pore structures, and the pore structures on the inner and outer surfaces of the membranes are completely different anisotropic structures. From these data, the partition coefficients and intramembrane diffusion coefficients of SARS-CoV-2 were quantified using the membrane transport model. Therefore, SARS-CoV-2 may permeate the membrane wall with the plasma filtration flow or wet lung. The risk of SARS-CoV-2 permeation is completely different due to each anisotropic pore structure. We theoretically demonstrate that SARS-CoV-2 is highly likely to permeate the membrane transporting from the patient’s blood to the gas side, and may diffuse from the gas side outlet port of ECMO leading to the extra-circulatory spread of the SARS-CoV-2 (ECMO infection). Development of a new generation of nanoscale membrane confirmation is proposed for next-generation extracorporeal membrane oxygenator and system with long-term durability is envisaged.

Highlights

Hollow fiber membrane oxygenator is used for cardiovascular surgery such as coronary artery bypass surgery, valve replacement, and implantable artificial heart surgery
As blood coagulation and thrombus are generated in severely ill patients with COVID-19 [9], incidents have been reported in which a blood flow path of membrane oxygenator is clogged in extracorporeal membrane oxygenation (ECMO) treatment
There is a concern that, if the blood coagulation and thrombus are generated in severely ill patients with COVID-19 [9] and they cause a more serious excessive pressure drop, the transmembrane pressure (TMP) is increased, and plasma and virus permeate through the membrane

Summary

Introduction

Hollow fiber membrane oxygenator (artificial lung) is used for cardiovascular surgery such as coronary artery bypass surgery, valve replacement, and implantable artificial heart surgery. It is incorporated into the extracorporeal membrane oxygenation (ECMO). The most serious dysfunctions in ECMO are the increased excessive pressure drop in blood flow path, plasma leakage, and decrease in gas exchange rate [4,5,6,7,8]. As blood coagulation and thrombus are generated in severely ill patients with COVID-19 [9], incidents have been reported in which a blood flow path of membrane oxygenator is 4.0/). There is a concern that the treatment for critically ill COVID-19 patients causes more serious excessive pressure drop

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