Development of a New Pulsatile Extracorporeal Life Support Device Incorporating a Dual Pulsatile Blood Pump

Preclinical Studies on Pulsatile Veno-Arterial Extracorporeal Membrane Oxygenation: A Systematic Review

Refractory cardiogenic shock is increasingly being treated with veno-arterial extracorporeal membrane oxygenation (V-A ECMO), without definitive proof of improved clinical outcomes. Recently, pulsatile V-A ECMO has been developed to address some of the shortcomings of contemporary continuous-flow devices. To describe current pulsatile V-A ECMO studies, we conducted a systematic review of all preclinical studies in this area. We adhered to PRISMA and Cochrane guidelines for conducting systematic reviews. The literature search was performed using Science Direct, Web of Science, Scopus, and PubMed databases. All preclinical experimental studies investigating pulsatile V-A ECMO and published before July 26, 2022 were included. We extracted data relating to the 1) ECMO circuits, 2) pulsatile blood flow conditions, 3) key study outcomes, and 4) other relevant experimental conditions. Forty-five manuscripts of pulsatile V-A ECMO were included in this review detailing 26 in vitro , two in silico , and 17 in vivo experiments. Hemodynamic energy production was the most investigated outcome (69%). A total of 53% of studies used a diagonal pump to achieve pulsatile flow. Most literature on pulsatile V-A ECMO focuses on hemodynamic energy production, whereas its potential clinical effects such as favorable heart and brain function, end-organ microcirculation, and decreased inflammation remain inconclusive and limited.

Effect of pulsatile flow perfusion on decellularization

Background

Decellularized animal organs have been used as scaffolds for tissue engineering. To make a properly functioning scaffolds, the extracellular matrix (ECM) components must be preserved after decellularization. Because pulsatile flow is known to be beneficial for tissue perfusion, pulsatile perfusion of a detergent might decrease the exposure time of the tissues to the detergent used for decellularization. Using Energy Equivalent Pressure (EEP) as a pulsatility parameter, the effect of pulsatile flow in decellularization process is studied.

Results

Twelve rat hearts were decellularization with 1% sodium dodecyl sulfate (SDS) solution for 2 h. They are divided into two groups, one with pulsatile perfusion (n = 6), the other with non-pulsatile perfusion (n = 6) of SDS. The initial mean perfusion pressures were same in both group. The result indicated that the EEP and the perfusion flow were increased significantly in the pulsatile group compared to the non-pulsatile group. Photographs taken during the decellularization showed more profound decellularization in the pulsatile group. The residual DNA content in the scaffolds was significantly lower in the pulsatile group. However, the level of ECM components, collagen and GAG showed no significant differences between the groups.

Conclusions

Decellularization is more efficient in pulsatile flow than in non-pulsatile flow but still preserves the ECM molecules.

Venous pressure regulation during pulsatile extracorporeal life support

During the use of pulsatile extracorporeal life support (pulsatile-ECLS), the patient's venous pressure near the inlet venous catheter tip must be monitored to maintain sufficient blood flow and to prevent vein collapse. However, direct measurement of the venous pressure and the estimate of suction using measured blood inflow and prepump pressure are not practical because of setup difficulties during emergency treatments and in cardiovascular operations. In this article, we describe a new method for estimating the venous pressure that can be implemented in the controller of the pulsatile-ECLS system, the T-PLS. It uses real-time measurement of the electric current and actuator motion. The current waveform of the T-PLS is used to determine the outflow amount and the volume remaining in the pulsatile pumps. Previously measured values of the pulsatile-ECLS compliance and the hemodynamic resistance along the inflow path are used to evaluate venous pressure with estimated blood flow. Estimated prepump pressure, inflow, and venous pressure were compared to the measured data in a series of in vitro experiments. The estimated venous pressure was used to avoid vein collapse and to increase the reliability in animal experiments.