The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
An automatic, on-line and real-time monitoring and estimation tool for the cardiovascular dynamics under pumping of the left ventricular assist device (LVAD) has been developed to unload the operator who has to pay constant attention to the LVAD operation. The tool can detect the presence and origin of accidents happening in the cardiovascular system, the pneumatic drive unit as well as the automatic...
Our team is developping a cardiac assist device consisting of a Wankel-type rotary pump driven by an electric motor. As an alternative to long term implantation of a pressure sensor to control motor speed, we have developed a mathematical model using current intensity of the electric motor.
In order to investigate the origin of the fluctuations in hemodynamic parameters, total artificial heart (TAH) replacement was performed in chronic animal experiments using adult goats. Two ventricular assist devices were implanted as total biventricular bypass (BVB) and natural heart was electrically fibrillated. The results suggest that fluctuations in the hemodynamics of the TAH animal are originated...
Design of a diagnostic technique used in an intelligent support system for artificial heart control is presented. Parameters which may cause abnormal variables of the recipient of artificial hearts are searched with the use of a large dynamic model Human. The advantage of this technique is that candidates of abnormal parameters can be pointed out avoiding real-time parameter estimation whose results...
In order to evaluate the efficacy of counterpulsation for different cardiac assist device configurations, a valveless single orifice polyurethane ventricle was implanted on the brachlocephalic artery in sheep(n=14) to provide extra-aortic counterpulsation. In parallel, an intra-aortic balloon was placed in the descending aorta. Both devices were pneumatically driven with a standard intra-aortic balloon...
Novacor has had clinical experience with implantable left ventricular assist systems since 1984. Following the clinical introduction and use of the console-based system, development of a compact, wearable, electronic control system was started. This is a life support device and reliability has always been a primary development concern within Novacor. This paper presents some of the considerations...
This study concerns the control of blood gases during extracorporeal circulation. The partial pressures of carbon dioxide and oxygen in the arterial blood can be controlled automatically by adjusting the total gas flow ventilating the artificial lung and its oxygen fraction. The hardware consisting of a continuous blood gas analyser, a controlled gas blender and an IBM PC is described together with...
This work presents an analysis about the limitation of ultrasonic air-bubble detectors based on the measurement of the wave attenuation caused by the presence of air-bubbles in the blood circuit. Considering as a lower limit the amount of 0.5 ml of air in 1 liter of blood for a blood flow rate of 250 ml/min then it is shown that for ultrasonic frequencies of 50 kHz, 100 kHz, 1 MHz and 5 MHz the detectors...
This paper presents an innovative method for the transcutaneous transmission of RF power and digital data via an inductive link. The system is based on the single ended class-E power amplification scheme. A self oscillating class-E tuned power amplifier involving an inductive link permits high-efficiency coupling-insensitive power transmission. The oscillation frequency is not fixed but influenced...
Platelet thrombus in the hemodialyzer, arterial and venous traps in the extracorporeal circuit was never quantified. Platelet consumption during hemodialysis was measured in Yorkshire pigs with In-111 labeled platelets. Six anesthetized pigs (20–25 kg) were hemodialyzed at 150 ml/min for 3 hours. All pigs were injected with autologous labeled platelets (300–420 μCi), 24 hours prior to dialysis and...
The rates of LDL and HDL adsorption were measured by circulating human plasma through cellulose diacetate filter while recycling both the permeate and the retentate. The relative contribution of adsorption to the removal rate was then evaluated using mass balance models for cross-flow filtration with (as in the experiment) or without recycling the retentate (normal procedure).
The experimental system for hydrodynamic performance testing procedure has been established. The artificial heart to be tested was inserted in the system and performance evaluation of the right and left sides of the heart was conducted independently. Visualization and laser-Doppler anemometry have yielded valuable information on the velocity field in some areas of the ventricle of the artificial heart...
We have to date investigated cardiac mechanics at the cellular level by monitoring cell force and cell length. However, the understanding of the biophysics of twitch contractions of cardiac muscle ultimately requires real time measurements of sarcomere length. In this report, we describe improvements to our instrumentation system which utilize a phase locked loop to track the changes in sarcomere...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.