Dr Michael Simmonds

Griffith University
Research Field: Physiology; blood rheology; mechanobiology

Life support during cardiothoracic surgical procedures involves a pump for distributing blood, and occasionally an oxygenator to facilitate gas exchange. Short-term lifesupport includes cardiopulmonary bypass, while long-term support is achieved using ventricular assist devices or even complete artificial hearts. These forms of life support are collectively known as “mechanical circulatory support” (MCS) and are essential for facilitating complex surgical procedures and management strategies that were previously unattainable.
An unfortunate consequence of MCS is the accumulation of “blood trauma”, which occurs due to the high shear forces within the blood pump, and free radical production in the oxygenator. Blood trauma is associated with increased morbidity and mortality, due likely to what we have coined the “MCS Paradox”: despite large vessel blood flow being promoted by MCS, flow through the smaller vessels of the body is impaired due to altered cell membrane properties.
We have identified that blood cell mechanics are irreversibly altered by the shear stresses and free radicals produced during MCS, and we are thus now developing novel biophysical approaches to eliminate blood trauma from these devices. Our interdisciplinary approach has had early successes that will have applications in design and manufacturing, leading to improved clinical outcomes following MCS use.