title: Sensorless controlling method for a continuous flow left ventricular assist device.
abstract: We originated a novel control strategy for a continuous flow left ventricular assist device (LVAD). We examined our method by acute animal experiments to change the left ventricular (LV) contractility or LV end-diastolic pressure (LVEDP). To estimate the pump pulsatility without any specific sensor, we calculated the index of current amplitude (ICA) from motor current waveform. The ICA had a peak point (t-i point) that corresponded closely with the turning point from partial to total assistance, and a trough (s-i point) that corresponded with the beginning point of ventricular collapse. The pump flow at the t-i point (Qt-i) had no component of flow regurgitation. In the evaluation of the effects of preload LVEDP, afterload (mAoP), and contractility (max LV dp/dt), we found that preload was the only parameter that significantly influenced Qt-i. We concluded that our method could well control continuous flow LVAD by preventing reversed flow and ventricular collapse.
authors.affiliation: Intensive Care Division, Medical Informatics, the Second Department of Surgery, Miyazaki Medical College, Miyazaki;Cardiovascular Surgery, Oita Medical University, Oita, Japan. mitsuoO@post.miyazaki-med.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Oshikawa
authors.forename: K
authors.initials: K
authors.lastname: Araki
authors.forename: G
authors.initials: G
authors.lastname: Endo
authors.forename: H
authors.initials: H
authors.lastname: Anai
authors.forename: M
authors.initials: M
authors.lastname: Sato
mesh_terms: D000818:Animals; D002498:Centrifugation; D004285:Dogs; D006353:Heart-Assist Devices; D006439:Hemodynamics; D018056:Hemorheology; D011673:Pulsatile Flow