title: Preload-based Starling-like control of rotary blood pumps: An in-vitro evaluation.
abstract: Due to a shortage of donor hearts, rotary left ventricular assist devices (LVADs) are used to provide mechanical circulatory support. To address the preload insensitivity of the constant speed controller (CSC) used in conventional LVADs, we developed a preload-based Starling-like controller (SLC). The SLC emulates the Starling law of the heart to maintain mean pump flow ([Formula: see text]) with respect to mean left ventricular end diastolic pressure (PLVEDm) as the feedback signal. The SLC and CSC were compared using a mock circulation loop to assess their capacity to increase cardiac output during mild exercise while avoiding ventricular suction (marked by a negative PLVEDm) and maintaining circulatory stability during blood loss and severe reductions in left ventricular contractility (LVC). The root mean squared hemodynamic deviation (RMSHD) metric was used to assess the clinical acceptability of each controller based on pre-defined hemodynamic limits. We also compared the in-silico results from our previously published paper with our in-vitro outcomes. In the exercise simulation, the SLC increased [Formula: see text] by 37%, compared to only 17% with the CSC. During blood loss, the SLC maintained a better safety margin against left ventricular suction with PLVEDm of 2.7 mmHg compared to -0.1 mmHg for CSC. A transition to reduced LVC resulted in decreased mean arterial pressure (MAP) and [Formula: see text] with CSC, whilst the SLC maintained MAP and [Formula: see text]. The results were associated with a much lower RMSHD value with SLC (70.3%) compared to CSC (225.5%), demonstrating improved capacity of the SLC to compensate for the varying cardiac demand during profound circulatory changes. In-vitro and in-silico results demonstrated similar trends to the simulated changes in patient state however the magnitude of hemodynamic changes were different, thus justifying the progression to in-vitro evaluation.
authors.affiliation: Department of Biomedical Engineering, University of Malaya, Kuala Lumpur, Malaysia.|Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, the Prince Charles Hospital, Brisbane, Queensland, Australia.
authors.forename: Mahdi
authors.identifier: http://orcid.org/0000-0002-7702-3249
authors.initials: M
authors.lastname: Mansouri
authors.affiliation: Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, the Prince Charles Hospital, Brisbane, Queensland, Australia.|School of Medicine, University of Queensland, Brisbane, Queensland, Australia.|School of Engineering, Griffith University, Brisbane, Queensland, Australia.
authors.forename: Shaun D
authors.initials: SD
authors.lastname: Gregory
authors.affiliation: Department of Intensive Care, Alfred Hospital, Prahran, Victoria, Australia.|Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Salamonsen
authors.affiliation: Graduate School of Biomedical Engineering, UNSW, Sydney, New South Wales, Australia.
authors.forename: Nigel H
authors.initials: NH
authors.lastname: Lovell
authors.affiliation: Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, the Prince Charles Hospital, Brisbane, Queensland, Australia.|Graduate School of Biomedical Engineering, UNSW, Sydney, New South Wales, Australia.|School of Medicine, University of Sydney, Camperdown, New South Wales, Australia.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Stevens
authors.affiliation: Innovative Cardiovascular Engineering and Technology Laboratory, Critical Care Research Group, the Prince Charles Hospital, Brisbane, Queensland, Australia.|School of Medicine, University of Queensland, Brisbane, Queensland, Australia.|School of Engineering, Griffith University, Brisbane, Queensland, Australia.
authors.forename: Jo P
authors.initials: JP
authors.lastname: Pauls
authors.affiliation: Department of Mechatronics Engineering, International Islamic University Malaysia, Kuala Lumpur.
authors.forename: Rini
authors.initials: R
authors.lastname: Akmeliawati
authors.affiliation: Department of Biomedical Engineering, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Einly
authors.initials: E
authors.lastname: Lim
mesh_terms: D002302:Cardiac Output; D003198:Computer Simulation; D004867:Equipment Design; D015444:Exercise; D006353:Heart-Assist Devices; D006439:Hemodynamics; D006801:Humans; D016277:Ventricular Function, Left / Q000502:physiology*