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Starling‐Like Flow Control of a Left Ventricular Assist Device: In Vitro Validation
Author(s) -
Gaddum Nicholas R.,
Stevens Michael,
Lim Einly,
Fraser John,
Lovell Nigel,
Mason David,
Timms Daniel,
Salamonsen Robert
Publication year - 2014
Publication title -
artificial organs
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.684
H-Index - 76
eISSN - 1525-1594
pISSN - 0160-564X
DOI - 10.1111/aor.12221
Subject(s) - preload , suction , starling , ventricular assist device , frank–starling law of the heart , controller (irrigation) , cardiology , control theory (sociology) , flow (mathematics) , sensitivity (control systems) , biomedical engineering , medicine , stroke volume , hemodynamics , computer science , mechanics , physics , heart failure , engineering , mechanical engineering , biology , control (management) , agronomy , ejection fraction , artificial intelligence , electronic engineering
Abstract The application of rotary left ventricular ( LV ) assist devices ( LVAD s) is expanding from bridge to transplant, to destination and bridge to recovery therapy. Conventional constant speed LVAD controllers do not regulate flow according to preload, and can cause over/underpumping, leading to harmful ventricular suction or pulmonary edema, respectively. We implemented a novel adaptive controller which maintains a linear relationship between mean flow and flow pulsatility to imitate native Starling‐like flow regulation which requires only the measurement of VAD flow. In vitro controller evaluation was conducted and the flow sensitivity was compared during simulations of postural change, pulmonary hypertension, and the transition from sleep to wake. The S tarling‐like controller's flow sensitivity to preload was measured as 0.39 L /min/ mm Hg , 10 times greater than constant speed control (0.04 L /min/ mm Hg ). Constant speed control induced LV suction after sudden simulated pulmonary hypertension, whereas S tarling‐like control reduced mean flow from 4.14 to 3.58 L/min, maintaining safe support. From simulated sleep to wake, S tarling‐like control increased flow 2.93 to 4.11 L /min as a response to the increased residual LV pulsatility. The proposed controller has the potential to better match device outflow to patient demand in comparison with conventional constant speed control.