Biomedical subjects
Publications and source records attributed to I V Melemuka.
The authors propose a design of an axial shovel pump for extracorporeal circulation. They show how to introduce it into various cardiovascular segments and make a comparative assessment of its efficacy in relation to the type and severity of heart failure, surgical access, and treatment policy.
Intraventricular blood-forcing-principle-based pneumo- and hydraulic assistance circulation device test results are proposed. The system consists of a uninipple valveless dome pump, a pneumo- or hydraulic drive, and an artificial pericardium. Stand tests of these systems and medical-biologic experiments on dogs and 17 calves were performed. The duration of these experiments was up to several days. In this report, the features of surgical techniques, perfusion parameters, control principles, hemodynamic variations, complications, and other problems concerning realization of the proposed method are discussed.
Thirty experiments were conducted on calves for hemodynamic study of mechanical aid to the heart (biventricular bypass by two artificial ++"Module"+ ventricles of the heart) in acute cardiac failure. The cavities of the heart were cannulated with a special perforating device which, when necessary, is an obturator of the main line. Analysis of the hemodynamic values showed a sufficiently high efficacy of biventricular shunting in acute cardiac failure. The device for draining the heart cavities has advantages over the traditional main lines, in particular the number of complications from bleeding and air embolism reduces with its use.
Experiments were conducted on 26 mongrel dogs and 10 calves to evaluate the effect of uni- and biventricular bypass created by means of artificial heart ventricle on hemodynamics in acute cardiovascular insufficiency (ACVI) and heart arrest (HA). The use of unilateral right-ventricular (RVB) and left-ventricular bypass (LVB) was shown to be equivocal: in sufficient functional reserve of the left-ventricular myocardium the volume blood flow in the aorta was increased to a greater degree by RVB (to 2.1 +/- 0.3 l/min) than by LVB (to 2.0 +/- 0.5 l/min). Experiments during HA allowed the authors to evaluate selectively the bypasses in maintenance of the systemic blood flow. It was found that in univentricular bypass the other half of the heart had an effect on hemodynamics, which depended on the initial hemodynamic parameters of the divisions of circulation with high and low pressure, the filling of the heart cavities with blood, and the effect produced through the interventricular septum. The increase of the volume blood flow in the aorta in RVB to 0.6 +/- 0.1 l/min is linked to a great measure by the authors with the conducted artificial ventilation of the lungs. It was noted that the greatest difficulties in maintaining the systemic blood flow in ACVI were associated with the development of disproportion of the contractile function of the right and left parts of the heart. With consideration for this circumstance, the indications for univentricular bypass are determined. A clinical case with prolonged use of LVB (8 days) is discussed.
Three clinical methods of circulatory assistance are described: intraaortic balloon counterpulsation, left ventricular bypass using a roller pump, and the artificial ventricle. All three methods have hemodynamic effectiveness. The first method is indicated in cases of widespread cardiosclerosis and pronounced coronary insufficiency and may be contraindicated in pathology of the valvular apparatus. The second method demonstrated a temporary positive effect in patients in whom it was not possible to discontinue artificial circulation. The artificial ventricle is useful in treating patients with cardiogenic shock following cardiac surgery.
A series of models of the artificial heart has been developed for simulating different heart defects including stenosis of the atrioventricular ostium and mitral and tricuspid incompetence. Simulation of ventricular fibrillation is also possible. Repeated perturbation and restoration of artificial heart function are possible in the same animal. These processes are controlled externally. The surgical technique of implanting the artificial heart does not differ from the usual technique. Models of the artificial heart permit the study of fundamental problems in the physiology and pathology of the cardiovascular system.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The authors offer a system for auxiliary circulation (a "hybrid man-made heart"), review design varieties, describe the functioning of the system. The paper is of interest for designers of the systems for extracorporeal circulation and for practicing physicians concerned with the problems of cardiology.
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The article gives the analysis of the authors' experience in developing the systems of mechanical maintenance of blood circulation: AvIK-9M, Sinus-BK, and the cylinder pump with an additional distal chamber, which has not only high hemodynamic efficiency but also, to a considerable extent, improves the bioenergetics of the myocardium. It also gives a detailed description of the device for the retrograde counterpulsation and periodic occlusion of the coronary sinus. All the systems have successfully undergone testing by experiment and in the clinic.
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An assisted circulation system having a HART-02 axial-flow micropump has been developed. The diameter of the micropump is 7 mm and its length is 20 mm, which allows it to be introduced into the ascending aorta through a peripheral artery. The system has a good biocompatibility, a low hemolysis and its productivity is as much as 3.5 liter/min.
The experience of the use of noninvasive assisted circulation in patients with cardiac pathology is summarized. It has been demonstrated that rhythmic pneumo-compression of the lower extremities, abdominal compression, muscular electrical stimulation of the lower extremities and the abdomen have a pronounced effect on circulation compartments with low pressure. All the above pre-determines the role of these techniques in the management of cardiac failure and in intensive care.
The method is based on the ability of inulin to activate the alternative route of the complement system. The alternative activity is assessed from the consumption of the third complement component as a result of interaction with inulin. C3 is measured in experimental and control samples by kinetic titration, which permits assessing the activation of the alternative route in patients sera in less than 2 hours.