Refurbishment of Extracorporeal Life Support Oxygenators in the Context of In Vitro Testing

Refurbishing single use extracorporeal membrane oxygenation
(ECMO) oxygenators for in vitro research applications
is common. However, the refurbishment protocols that are
established in respective laboratories have never been evaluated.
In the present study, we aim at proving the relevance of
a well-designed refurbishing protocol by quantifying the burden
of repeatedly reused oxygenators. We used the same three
oxygenators in 5 days of 6 hours whole blood experiments.
During each experiment day, the performance of the oxygenators
was measured through the evaluation of gas transfer.
Between experiment days, each oxygenator was refurbished
applying three alternative refurbishment protocols based on
purified water, pepsin and citric acid, and hydrogen peroxide
solutions, respectively. After the last experiment day, we disassembled
the oxygenators for visual inspection of the fiber
mats. The refurbishment protocol based on purified water
showed strong degeneration with a 40-50 %-performance
drop and clearly visible debris on the fiber mats. Hydrogen
peroxide performed better; nevertheless, it suffered a 20%
decrease in gas transfer as well as clearly visible debris.
Pepsin/citric acid performed best in the field, but also suffered
from 10% performance loss and very few, but visible
debris. The study showed the relevance of a well-suited and
well-designed refurbishment protocol. The distinct debris
on the fiber mats also suggests that reusing oxygenators is
ill-advised for many experiment series, especially regarding
hemocompatibility and in vivo testing. Most of all, this study
revealed the relevance of stating the status of test oxygenators
and, if refurbished, comment on the implemented refurbishment
protocol in detail.