Effects on the pulmonary hemodynamics and gas exchange with a speed modulated right ventricular assist rotary blood pump: a numerical study

Lei²,

Ying³

et al. 2023

Front. Physiol.

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Introduction: Speed modulation methods have been studied and even used clinically to create extra pulsation in the blood circulatory system with the assistance of a continuous flow rotary blood pump. However, fast speed variations may also increase the hemolysis potential inside the pump.Methods: This study investigates the hemolysis performance of a ventricular assist rotary blood pump under sinusoidal, square, and triangular wave speed modulation profiles using the computational fluid dynamics (CFD) method. The CFD boundary pressure conditions of the blood pump were obtained by combining simulations with the pump’s mathematical model and a complete cardiovascular lumped parameter model. The hemolysis performance of the blood pump was quantified by the hemolysis index (HI) calculated from a Eulerian scalar transport equation.Results: The HI results were obtained and compared with a constant speed condition when the blood pump was run under three speed profiles. The speed modulations were revealed to slightly affect the pump hemolysis, and the hemolysis differences between the different speed modulation profiles were insignificant.Discussion: This study suggests that speed modulations could be a feasible way to improve the flow pulsatility of rotary blood pumps while not increasing the hemolysis performance.

Section: Discussionmentioning

confidence: 99%

Numerical hemolysis performance evaluation of a rotary blood pump under different speed modulation profiles

Lei²,

Ying³

et al. 2023

Front. Physiol.

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“…The systemic and pulmonary venous systems are both characterized simply by lumped resistance and lumped compliance. More details and parameter values could be referred to the reference [ 11 , 12 ].…”

Section: Methodsmentioning

confidence: 99%

“…A complete numerical model of the cardiovascular system from a previous study [11], shown in Fig 2, is adopted in this study to provide a platform for validating the on-line identification algorithm. The cardiovascular model includes both systemic and pulmonary circulation.…”

Section: Cardiovascular Modelmentioning

confidence: 99%

On-line parameter identification of the lumped arterial system model: A simulation study

Ying

2020

PLoS ONE

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A lumped model of the arterial system has been used in constructing a hybrid mock loop due to its real-time response. However, the parameters of the model are always from a general case and not adapted to a specific patient. In this study, we focused on on-line parameter identification of the lumped model of the arterial system that could be used for a specific patient. A five-element lumped arterial model is adopted in this study, in which the five parameters are to be determined. The aortic flow rate and the venous pressure are chosen as the inputs of the model, and aortic pressure as the output. An iterative optimization based on the established state space equations of the five-element model is used to seek the best parameter values by minimizing the difference between the model prediction and the previously obtained aortic pressure. The method is validated using simulated data from a complete numerical cardiovascular model. Results show that the method can track the dynamic variation of the parameters very well. Finally, a sensitivity analysis of the model parameters is conducted to interpret the effect of parameter changes. The good performance of the identification demonstrates the potential application of this method to customize a hybrid mock loop for a specific patient or clinically monitor the arterial vessel characteristics in real time.

“…The whole numerical model, shown in Figure 2, mainly contains the following four sub-models: a cardiovascular model, which includes both systemic and pulmonary circulatory pathways; an airway mechanics model; an O 2 gas exchange model; and an RBP model. 15 The cardiovascular model interacts with the gas exchange model by time-varied blood flow, while the gas exchange model describes the diffusion of gas from the airway mechanics model across the alveolar–capillary membrane. The connections between the sub-models are clearly shown in Figure 2.…”

Section: Methodsmentioning

confidence: 99%

Preliminary evaluation of a predictive controller for a rotary blood pump based on pulmonary oxygen gas exchange

Gou

2019

Proc Inst Mech Eng H

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Physiological control of rotary blood pumps is becoming increasingly necessary for clinical use. In this study, the mean oxygen partial pressure in the upper airway was first quantitatively evaluated as a control objective for a rotary blood pump. A model-free predictive controller was designed based on this control objective. Then, the quantitative evaluation of the controller was implemented with a rotary blood pump model on a complete cardiovascular model incorporated with airway mechanics and gas exchange models. The results show that the controller maintained a mean oxygen partial pressure at a normal and constant level of 138 mmHg in the left heart failure condition and restored basic haemodynamics of blood circulation. A left ventricular contractility recovery condition was also replicated to assess the response of the controller, and a stable result was obtained. This study indicates the potential use of the oxygen partial pressure index during pulmonary gas exchange when developing a multi-objective physiological controller for rotary blood pumps.