Development of a Reliable Automatic Speed Control System for Rotary Blood Pumps

Vollkron, Michael; Schima, Heinrich; Huber, Leopold; Benkowski, Robert; Morello, Gino; Wieselthaler, Georg

doi:10.1016/j.healun.2005.02.004

Cited by 79 publications

(78 citation statements)

References 14 publications

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“…The IP Ao value becomes smaller when the frequency increases; consequently, the IP Ao fixed value control strategy presented here will respond with a decrease in pump speed to maintain the reference index value. This type of response would be the opposite to the one expected in heart failure patients with preserved native heart rate based control (30). Therefore, the IP Ao should be related to the heart rate; a possible example is the implementation of an adaptative control system where the reference IP Ao value is modified by the heart rate.…”

Section: Discussionmentioning

confidence: 98%

In Vitro Evaluation of an Axial Flow Pump: Mock-Pump Interaction and an Approach to Control

et al. 2007

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Section: Discussionmentioning

confidence: 98%

In Vitro Evaluation of an Axial Flow Pump: Mock-Pump Interaction and an Approach to Control

et al. 2007

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“…Nakamura et al exercised calves using treadmill tests, increasing the speed of the treadmill over 3 minute intervals, when evaluating pulsatile TAH control systems [129]. In the landmark clinical evaluation of their control system, Vollkron et al [84] and Schima et al [130] performed ergometric exercise of LVAD patients, monitoring electrocardiograms, CVP, RAP, LAP, PAP, AoP, LVAD flow and RV cardiac output. Assuming that the animal or patient is stable, functional and mobile, exercise based evaluation is simple to perform.…”

Section: Exercisementioning

confidence: 99%

“…Multi-objective control (MOC) strategies involve combining two or more control objectives into a [84] More recently, Karantonis and colleagues (2010) proposed a MOC system that relied on the input from an accelerometer combined with HR as an indicator of patient activity level [169]. This formed part of a 6-level hierarchical controller, which meets the following objectives (in order)…”

Section: Multi-objective Controlmentioning

confidence: 99%

“…Notable omissions included work by Arndt et al [82], [83], Vollkron and colleagues [84], Choi et al [80], [95] and Gwak et al [86], [87]. These controllers were omitted because their complexity, in conjunction with insufficient detail of controller parameters in their published descriptions, made it difficult to implement them in this experimental setup within the time frame.…”

Section: Experimental Limitations and Future Workmentioning

confidence: 99%

“…Careful consideration must be given to the switching between different control systems. Of the MOCs presented in this literature review, only Gwak et al [85] and Vollkron et al [84] gave details as to how they managed the interaction between the different objectives.…”

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Automatic control of dual left ventricular assist devices as a biventricular assist device

Stevens¹

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In this thesis, we investigate automated methods for the control of rotary blood pumps in the treatment of heart failure. Heart failure is a common end-point for many forms of cardiovascular disease resulting in significant morbidity and mortality. Ventricular assist devices (VADs) are blood pumps designed to assist a failing heart and are used both to support patients whilst they are awaiting a heart transplant, or as an alternative to transplantation. Small rotary VADs can provide long-term support of the left ventricle (LVAD), right ventricle (RVAD) or both ventricles of the heart simultaneously.Unfortunately, the lack of a commercially available rotary RVAD has led to the implantation of two rotary LVADs as an ad hoc biventricular assist device (BiVAD). Clinicians currently operate such dual LVADs at a constant speed, which ensures balanced left and right pump flows for inactive patients.However, changes in levels of patient activity will lead to altered cardiac output requirements, which may disturb this balance. In turn, this can lead to undesirable events such as pulmonary venous congestion or ventricular suction. A control system that automatically adjusts pump speed with changes in the required cardiac output could alleviate such events and so offer significant benefits. However, while such physiological control systems have been investigated for single LVADs, limited work has been completed on dual LVAD control. In addition, there is no generally accepted framework for the evaluation of these systems that encompasses a broad range of patient scenarios, activity levels and heart conditions. Therefore, the primary aim of this thesis was to develop and evaluate a number of physiological control systems suitable for dual rotary LVADs.The first objective was to characterise the methods that are currently used to operate dual LVADs in the clinic. Using both in-vitro and in-vivo methods, it was shown that balanced left and right flow rates could be obtained by operating the RVAD slower than the LVAD, albeit at speeds below the manufacturer's recommendations (1400 -1800 RPM), which, according to other investigators, may adversely affect impeller washout. Operating both at the same design speed is only possible in patients with high pulmonary vascular resistance (PVR), high left ventricular contractility or high RVAD outflow cannula resistance. This thesis demonstrates that if the RVAD outflow cannula is restricted to a diameter between 6.5 and 8.1 mm, suitable steady-state haemodynamics (systemic flow rate 5 L.min -1 , MAP 90mmHg and LAP less than 25mmHg) can be achieved while maintaining impeller stability and optimal device washout. It was also established that changes in pump speed or outflow graft diameter were required to overcome elevations in pulmonary vascular resistance, thereby justifying the necessity of a physiological control system for dual LVADs.The second objective was to develop an in vitro evaluation protocol for control system testing utilising a mock circulation loop (MCL). The test...

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Novel Solutions for Patient Monitoring and Mechanical Circulatory Support Device Control

Moscato

Gross

Schlöglhofer

et al. 2020

Mechanical Support for Heart Failure

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Development of a Reliable Automatic Speed Control System for Rotary Blood Pumps

Cited by 79 publications

References 14 publications

In Vitro Evaluation of an Axial Flow Pump: Mock-Pump Interaction and an Approach to Control

In Vitro Evaluation of an Axial Flow Pump: Mock-Pump Interaction and an Approach to Control

Automatic control of dual left ventricular assist devices as a biventricular assist device

Novel Solutions for Patient Monitoring and Mechanical Circulatory Support Device Control

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