Researchers are utilizing
computational fluid dynamics (CFD) to model blood flow through
commercial membrane oxygenators. Since blood has a tendency to
clot where flow is sufficiently slow or in zones of recirculation,
the ability of CFD to predict the regions of the adult oxygenator
where blood clots form is verified by directly comparing CFD results
with maps showing regions likely to develop clots. These oxygenator
maps of thrombotic deposition have been made by collecting, sectioning,
and photographically analyzing oxygenators used in the clinic.
CFD can also be used to predict how well an oxygenator is transporting
oxygen to blood flowing in various regions of the device. Generally,
in regions where blood flow is relatively slow, oxygen transfer
is less efficient. Researchers are therefore using CFD to model
oxygen transport at various sites within the adult oxygenator
and attempting to predict what level of blood oxygenation can
be expected at the outlet of the device. To verify model results
a variety of imaging techniques are being used to quantify blood
flow patterns within the oxygenators.
Modeling Oxygenator Performance and Biocompatibility
Blood oxygenators have revolutionized the treatment of heart disease since
the introduction of this technology almost 50 years ago. Today approximately
500,000 oxygenators are employed annually worldwide. While the majority
of patients temporarily supported by these devices suffer no significant
complications, for a certain percentage, particularly the very young (neonates),
the elderly, and the very sick, passage of blood through the extracorporeal
circuit is poorly tolerated. Blood clotting in the oxygenator is of particular
concern, since it can lead to bleeding from surgical incisions, stroke,
and device failure. Building oxygenators that are more efficient and cause
fewer hemostatic alterations would provide direct patient benefit and
widen the applicability of these devices.