• Journal of Chest Surgery
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• v.37 no.12
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• pp.1003-1009
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• 2004

Mechanical circulatory support (MCS) has been used for myocardium failure, but moreover, it may be essential for the life support in cardiac arrest or cardiogenic shock. Many commercial devices can be used effectively for the long-term support. However, there are some limitations in the aspects of the cost and technical support by production company. Short-term support with centrifugal type has been reported numerously with the purpose of bridging to heart transplantation or recovery. We successfully treated 5 patitents who were in the status of cardiogenic shock (n=3) or arrest (n=2) with the technique of extracorporeal life support system (ECLS) or left ventricular assist device (LVAD) using the centrifugal type pump. The MCS were performed emergently (n=2) under cardiac arrest caused by ischemic heart disease, and urgently (n=3) under cardiogenic shock with ischemic heart disease (n=1) or acute fulminant viral myocarditis (n=2). All patients were weaned from MCS. Complications related to the use of MCS were bleeding and acute renal failure, but there were no major complications related to femoral cannulations. Mechanical circulatory support may be essential for the life support and rescue in cardiac arrest or cardiogenic shock.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.9
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• pp.739-745
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• 2014

Although medication is given to heart disease patients, conventional medication alone is not sufficient to treat heart disease. However, it has been reported that left ventricular assist device (LVAD) transplantation is an effective bridge to heart transplantation by assisting cardiac function. This study used long-term animal testing and emergency situations with a bovine model (Holstein) and canine model (Labrador-retriever) to evaluate the biocompatibility of LibraHeart-I (LH-1), which is a bent-tube type of LVAD that was developed in a previous study. In the long-term animal testing with the bovine model, the subjects survived for 49 days with no irregularities observed in their complete blood cell counts or the vital sign tests that were carried out during the test period. In short-term animal testing with the canine model, it was observed that blood did not remain inside the LH-I even without power support from an external drive source. In this study, the biocompatibility of the LH-I that was developed in a previous study was verified by the ejection performance during long-term animal testing and emergency situations.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.12
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• pp.1061-1065
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• 2002

Sensors need to be implanted to obtain necessary information for LVAS (Left Ventricular Assist System) operations. Size of the sensors can prevent them from being implanted in a patient and reliabilities of the sensors are questionable for a long term use. In this wort we utilize a developed pump model to estimate flow and pressure difference across the pump without implanted sensors and present a method to obtain the physiological variables as aorta pressure and left ventricle pressure from the pump model and pulsatility of flow estimate or pressure difference estimate. These estimated variables can be used for LVAS control as an index or indices.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.260-266
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• 1996

In this paper, we presents neural network identification and control of highly complicated nonlinear Left Ventricular Assist Device(LVAD) system with a pneumatically driven mock circulation system. Generally the LVAD system need to compensate nonlinearities. Hence, it is necessary to apply high performance control techniques. Fortunately, the neural network can be applied to control of a nonlinear dynamic system by learning capability. In this study, we identify the LVAD system with Neural Network Identification. Once the NNI has learned the dynamic model of LVAD system, the other network, called Neural Network Controller(NNC), is designed for control of a LVAD system. The ability and effectiveness of identifying and controlling a LVAD system using the proposed algorithm will be demonstrated by computer simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.3
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• pp.315-320
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• 1998

In this paper, we present the PID control method for the controlling flow rate of highly complicated nonlinear Left Ventricular Assist Device(LVAD) with pneumatically driven mock circulatory system. Beat Rate (BR), Systole-Diastole Rate (SDR) and flow rate are used as the main variables of the LVAD system. System modeling is completed using the neural network with input variables (BR, SDR, their derivatives, actual flow) and an output valiable(actual flow). Then, as the basis of this model, we perform the simulation of PID control to predict the performance and tendency of the system and control the flow rate of LVAD system using the PID controller. The ability and effectiveness of identifying and controlling a LVAD system using the proposed algorithm will be demonstrated through computer simulation and experiments.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1205-1211
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• 2011

In this paper, we developed a pacemaker that can increase the efficacy of a left ventricular assist device (LVAD) and increase the survival rate for patients suffering end-stage heart failure. Because LVAD patients can experience arrhythmia, the pacemaker incorporated into the LVAD has the important role of sustaining sufficient blood circulation during arrhythmia. The electrode of the pacemaker is located at the apex of the left ventricle, where the VAD's inlet cannula is connected. This is efficient placement, in that the electrode can transmit electrical stimulation directly to the Purkinje fibers of the myocardium. The pacemaker can change the stimulation rate from 0 bpm to 191.4 bpm when a button is pressed on the external control module, and the pacemaker normally stimulates the heart at 60 bpm with 0.25 J of energy. We performed animal experiments to evaluate the performance and reliability of the combination of the LVAD and pacemaker. At pacemaker stimulation rates of 86.4 bpm, 100.2 bpm, 126.6 bpm, we recorded the ECGs, aortic pressures, and flow rates to analyze the heart loads.

• Journal of Sensor Science and Technology
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• v.9 no.1
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• pp.51-60
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• 2000

This paper outlines the development of a non-pulsatile axial flow type blood pump control system. By utilizing blood pressure and heart rate, this system can assist the left ventricle in controlling blood pressure and blood volume. The system is comprised of a blood pump, signal sensor, signal interface, and signal-processing component. A control algorithm is also proposed which can control non-pulsatile, continuous blood flow in the human circulatory system. To facilitate the control required for non-pulsatile blood pump in a physiological system, an experimental control rule was developed utilizing ECG and blood pressure data, both of which are easily detectable variables in the body. The system was then tested using a mock-up circulation system and we found that it is possible that this systems could be temporarily used in clinic.

• Journal of Korean Clinical Nursing Research
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• v.28 no.2
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• pp.167-176
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• 2022

Purpose: Driveline infection (DLI) is one of the major adverse events of Left Ventricular Assist Device (LVAD). The purpose of this study was to explore the incidence of DLI according to the driveline dressing methods. Methods: This study was a retrospective cohort study that investigated the medical records of 75 patients who implanted LVAD from January 2015 to December 2020 at a hospital in Seoul, Korea. Traditionally, sandwich dressing method was applied until October 2019, after which newly winded dressing method was adopted for driveline dressing to LVAD patients. The outcome variables were compared between sandwich dressing method applied group (n=41) and winded dressing method applied group (n=34). The follow-up period for DLI was 1 year. Results: When compared participants' characteristics, there was no difference between the two groups, except the type of LVAD device. The incidence of DLI was 17.1% in sandwich dressing group, while no infection was found in winded dressing group (p=.011). Conclusion: Although there were difference in the LVAD devices, it is considered that winded dressing contributed to the reduction of DLI. Further research on standardized dressing methods was required for DLI prevention in Korea.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.235-236
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• 1998

The purpose of this paper is to develop diaphragm type pneumatic Left Ventricular Assist Device(LVAD) for clinical application and to evaluate its performance through the mock circulation and animal experiment. The blood housing and diaphragm are made by polyurethane. The relations of cardiac output us. beat rate and cardiac output vs. systolic-to-diastolic rate was estimated through the mock test and hemodynamic waves are recorded for the evaluation of VAD. We performed animal experiment and 4 animals survived more than 24hrs. As a result, the hemodynamic data and waves showed this system can be applicable to the animal experiment.

• Journal of Biomedical Engineering Research
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• v.36 no.4
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• pp.135-142
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• 2015

Outflow cannulation site of left ventricular assist device(LVAD) chosen by considering anatomical structure of thoracic cavity and vascular system. Though outflow cannulation site influences blood perfusion at each branch, there is no standard rule or quantitative data. In this study, we computed the amount of blood perfusion at each arterial branch numerically according to outflow cannulation sites(ascending aorta, aortic arch, descending aorta). We generated computational meshes to the three-dimensionally reconstructed arterial system. Clinically measured arterial pressure were used for inlet boundary condition, porous media were applied to mimic blood flow resistance. Blood perfusion through left common carotid artery was 2.5 times higher than other cases, and that through right common carotid artery was 1.1 times higher than other branches. Although this is simulation study, will be useful reference data for the clinical study of LVAD which considers blood perfusion efficiency.