Improving adult pulsatile minimal invasive extracorporeal circulation in a mock circulation

Abstract

Background: 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.Methods: 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. Results: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. Conclusions: 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.

A novel pulsatile blood pump design for cardiothoracic surgery: Proof‐of‐concept in a mock circulation

“…After finding no substantial effects of pulsation other than reduced blood losses in a prospective randomized trial with MiECC, 10 we hypothesized that the transfer of pulsatile energy into the patient may be inefficient in adult cardiac surgery. In our experiments using a mock circulation and a diagonal pump, 11,12 careful selection of components and optimized pump settings boosted surplus hemodynamic energy (SHE) 13,14 as a measure of pulsatile effectiveness only at low flow speeds. Alternative pump designs may help to overcome these limitations.…”