The Baylor Gyro centrifugal blood pump used a Frank-Starling type flow auto-regulation during in vitro studies. At a fixed speed of 2000 RPM, pump flow varied from 3.5 to 6 L/min over a range of inflow pressures (0–15mm Hg). The purpose of this study was to assess whether a fixed RPM control method is applicable for in vivo and possible clinical application.
Three BVAD animals surviving for 3 months were subjected to this study. Mean systemic pressure with LVAD and mean pulmonary artery pressure with RVAD were continuously recorded. Pump flow and heart rate were also recorded every 30 minutes for seven consecutive days. The pump flow changes under the fixed RPM were studied.
LVAD and RVAD pump flow were maintained between 3.4 to 5.8 L/min and from 4.7 to 6.4 L/min with fixed RPM of 1902 + 6 and 1754 + 1 respectively in case 1. Similarly 4.0–5.5 L/min and 4.1–7.0 L/min requiring RPM of 1960 + 24 and 1650 + 47 respectively in case 2, 4.1–5.7 L/min and 4.9–6.1 L/min requiring RPM of 1852 + 29 and 1750 + 40 respectively in case 3.
The Gyro PI pump automatically changes the required outflow; thereby, demonstrating Frank-Starling type of auto-regulation during this in vivo study.