In Vitro Pumping Performance Evaluation of the Ension Pediatric Cardiopulmonary Assist System for Venoarterial and Venovenous ECMO

Abstract

The purpose of this study is to determine the pumping performance of Revision 7 of the Ension pediatric cardiopulmonary assist system (pCAS) when used with cannulae for venoarterial (VA) or venovenous (VV) extracorporeal membrane oxygenation (ECMO). It was hypothesized that the pCAS could deliver flow rates within recommended ranges needed to provide adequate cardiopulmonary support for neonates and infants. Rev 7 pCAS pumping performance was evaluated with the pCAS incorporated into an ECMO circuit connected to an instrumented pediatric mock circulation with cannulae combinations commonly used clinically for VA ECMO or dual lumen cannulae for VV ECMO. The pCAS motor speed was operated from 0 to 4500 rpm while the pCAS pumped blood analog solutions representing a clinically relevant range of viscosity. Maximum flow rates were inversely related to viscosity and were directly proportional to cannulae size. At 4500 rpm, maximum pCAS flow for the VA ECMO configuration was 2.14 L/min for the lowest viscosity and largest cannula combination and 0.72 L/ min for the highest viscosity and the smallest cannulae combination. At a flow of 0.5 L/min, the pressure drop across the pCAS ranged from 121 to 323 mmHg depending on viscosity and cannulae combination. For the VV ECMO configuration at 4500 rpm, the maximum pCAS flow was 1.21 L/min for the lowest viscosity and largest cannula and 0.58 L/min for the highest viscosity and smallest cannula. For a flow of 0.5 L/min, the pressure drop across the pCAS ranged from 82 to 407 mmHg depending on the viscosity and cannula. Possible transition to turbulent flow (Re > 2100 at cannula inlet) was found at the higher flow rates achieved with the lower viscosity test fluid for all cannulae tested. In conclusion, across the range of pump speeds and fluid viscosities evaluated, the pCAS can generate the flow rates recommended to provide adequate cardiopulmonary support for neonates and infants with commonly used clinical cannulae combinations, thus confirming the hypotheses.

Pressure and flow properties of dual-lumen cannulae for extracorporeal membrane oxygenation

“…As shown in Supplemental Digital File 1, comparing our results with published data using both water and different blood-mimicking fluids, showed similar values for the larger cannulae, whereas larger differences were observed for the smaller cannulae. [20][21][22][23] This The present investigation indicates that the flow medium used for pressure-flow charts did matter as earlier shown in single-lumen cannulae. 11,12 Probably, more so in DLCs, where the two luminae are interdependent of each other sharing a finite cannula cross-section area limited by the cannula's outer diameter.…”

“…As shown in Supplemental Digital File 1, comparing our results with published data using both water and different blood-mimicking fluids, showed similar values for the larger cannulae, whereas larger differences were observed for the smaller cannulae. 20–23 This highlights the importance of more detailed studies needed to understand the dynamics of the fluid properties to assess uncertainties of choice of fluid medium on the results.…”

Neonatal respiratory and cardiac ECMO in Europe

“…Electrolytes are added to maintain physiologic levels. Cannulas are generally chosen according to the vessels' size, often evaluated with ultrasound [86] (Table 4).…”

Ex vivo models for research in extracorporeal membrane oxygenation: a systematic review of the literature

“…More complex designs often seek to account for systemic variables such as vascular resistance and compliance. Pantalos et al 41,42 have published several papers describing iterative revisions of their pediatric cardiopulmonary assist system (pCAS), which integrates a pump mechanism and a hollow-fiber oxygenator in a single housing. Seeking to recapitulate an in vivo setting more comprehensively, they have reported using a mock circulation comprising two pneumatic VADs, which simulate the right and left ventricles.…”