In vitro evaluation of the performance of Korean pulsatile ECLS (T-PLS) using precise quantification of pressure-flow waveforms

The Twin-Pulse Life Support System (T-PLS) is a novel pulsatile extracorporeal life support system developed in Korea. It has been reported that the T-PLS achieves higher levels of tissue perfusion of the kidney during short-term extracorporeal circulation and provides more blood flow to coronary artery than nonpulsatile blood pumps. However, these results lack pulsatility quantifications and thus make it hard to analyze the effects of pulsatility upon hemodynamic performance. We have adopted the concepts of hemodynamic energy, energy equivalent pressure (EEP), and surplus hemodynamic energy (SHE) to evaluate pulsatility performance in the different circuit configurations of the T-PLS and a membrane oxygenator (MO) in vitro. In a mock system, three different circuits were constructed depending on the location of an MO: pump-MO-pump (serial), MO-pumps (parallel A), and pumps-MO (parallel B). In parallel A, a low-resistance MO was used to preserve the pulsatility from the pump. All circuits showed good pulsatility in terms of EEP (serial: 13.2% ± 3.2%, parallel A: 10.0% ± 1.6%, parallel B: 7.00% ± 1.1%; change from aortic pressure to EEP; p < 0.003). The SHE levels were 17,404 ± 3,750 ergs/cm³, 13,170 ± 1,486 ergs/cm³, and 9,192 ± 1,122 ergs/cm³ in each circuit setup (p < 0.001). Although EEP levels were somewhat lower, both parallel types provided higher pump output compared with the serial type (serial: 1.87 ± 0.29 I/min, parallel A: 3.09 ± 0.74 I/min, parallel B: 3.06 ± 0.56 I/min; p < 0.003 except parallel A vs. parallel B, p = 0.90). Conclusively, the precise quantifications of pressure flow waveforms, EEP, and SHE are valuable tools for evaluating pulsatility of the mechanical circulatory devices, and are expected to be used as additional performance indexes of a blood pump. The pulsatility performances are different according to circuit setups. However, the parallel A circuit could achieve higher pump output and generate adequate pulsatility level. Thus, the parallel A circuit is suggested as the optimal configuration in T-PLS applications.