Improving adult pulsatile minimal invasive extracorporeal circulation in a mock circulation

Pulsatile extracorporeal circulation (ECC) may improve perfusion of critical organs during cardiac surgery. This study analyzed the influence of the components of a minimal invasive ECC (MiECC) on the transfer of pulsatile energy into the pseudo-patient of a mock circulation.

An aortic model with human-like geometry and compliance was perfused by a diagonal pump. Surplus hemodynamic energy (SHE) was determined from flow and pressure data. Five adult-size oxygenator models and three sizes of cannulas were compared. Pulsatile pump settings were optimized, and parallel dual-pump configurations were evaluated.

Oxygenator models showed up to twofold differences in pressure gradients and influenced SHE at flow rates up to 2.0 L min^-1 . Adjustments of frequency, systole duration, and rotational speed gain significantly improved SHE compared with empirical settings, with SHE above 21% of mean arterial pressure at flow rates of 1.0 L min^-1 to 1.5 L min^-1 and SHE above 5% at 3.5 L min^-1 . Small diameter cannula (15 Fr) limited SHE compared with larger cannula (21 Fr and 23 Fr). Two diagonal pumps did not provide higher SHE than a single pump, but permitted additional control over pulse pressure and SHE by varying the total fraction of pulsatile flow and the fraction of flow bypassing the oxygenator.

Proper selection of components and optimizations of pump settings significantly improved pulse pressure and SHE of pulsatile MiECC. Surplus hemodynamic energy depended on flow rate with a maximum at 1.0 L min^-1 -1.5 L min^-1 . Pulsatile MiECC may specifically assist organ perfusion during phases of low flow.