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Biomedical subjects

V E Tolpekin

Publications and source records attributed to V E Tolpekin.

At least 19 recordsLinked to original sources
PubMed2006

[Auxiliary blood circulation and the artificial heart: forty years of development].

The article summarizes forty-year experience in working over the problem of the artificial heart and auxiliary blood circulation in Laboratory and later Research Institute of Transplantology and Artificial Organs. This work has resulted in the development of balloon pumps for intraaortic contrapulsation, the technique of balloon installation, and indications to its application. The results of the clinical application of the method in patients with various pathologies have been estimated. Preclinically, left ventricular bypass techniques have been tested on more than twenty models of membrane type artificial ventricles. The results of the clinical application of left ventricular bypass have been analyzed. The authors adduce data on the development of the thermomechanical implantable bypass system "Micron-M". After achieving 100-day survival of calves with an artificial heart, an artificial heart with external power supply was used as a "bridge" to heart transplantation, but there was only one patient in whom transplantation was performed. The authors consider development of implantable auxiliary blood circulation devices and the artificial heart to be of great prospective value.

Animals↗
PubMed1999

Pulsate regimes of the centrifugal pump operation for assisted circulation.

This paper focuses on the evaluation of dynamic pumps as an element of the assist unit from the standpoint of its capacity to pass and change the left ventricle's pulsations. Analyses of the dynamic equations of the pipelines and pump have been performed. The pump intensification capacity of the disc and blade pumps was computed. Theoretically it was determined and experimentally confirmed that the pump intensification capacity was defined by the performance of the pump head. It was also determined that the existing pumps (e.g., The BioMedicus Biopump and the Moscow Aviation Institute, OK) pass and attenuate the left ventricle pressure pulsations.

Heart-Assist Devices↗
PubMed1992

[Schemes for implanting shovel pumps for assisted circulation].

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.

Assisted Circulation↗
PubMed1991

Perspectives for pneumatic and hydraulic circulatory assist devices and their application for heart transplantation.

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.

Animals↗
PubMed1991

[Biventricular auxiliary system for restoration of cardiac activity].

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.

Acute Disease↗
PubMed1990

[Electric stimulation of skeletal muscles as the optimal method of left-ventricular bypass].

Experiments were performed on 15 mongrel dogs to evaluate the influence of electrostimulated contractions of the hind limb and abdominal skeletal muscles on the efficacy of assisted circulation (AC). The influence of massage of the abdomen on AC efficacy was studied in 10 experiments. In electrostimulation of the hind limb muscles the drainage along the femoral vein, measured by the direct method, increased threefold: from 58 +/- 9 to 162 +/- 7 ml/min under conditions of an intact heart and from 5.8 +/- 0.8 to 15 +/- 1.2 ml/min in cardiac insufficiency. The efficacy of AC by the method of left-ventricular bypass by means of the Module artificial heart ventricle (AHV) increased through the flow of blood to the heart, which was manifested by greater AHV performance with rise of systolic and diastolic pressure to 7-8 mm Hg. In cardiovascular insufficiency the influence of electrostimulation on AC efficacy was weaker, the systolic and diastolic pressure increased only by 2-4 mm Hg, in massage of the abdomen both indices increased by 8-10 mm Hg.

Abdominal Muscles↗
PubMed1990

[Clinical use of artificial heart ventricles].

The article discusses the results of applying for the first time Soviet-made "Modul" and "Yasen" artificial ventricles of the heart (AVH) in a left ventricular bypass regimen in patients with refractory cardiac insufficiency. Improvement of AVH design and rational tactics of attendant drug therapy allowed the period of the safe application of the AVH in the organism to be increased to more than 8 days.

Adult↗
PubMed1987

Paracorporeal assistance system for restoring cardiac activity.

Two series of experiments were conducted to assess the potential of artificial ventricular bypass in restoring cardiac activity. One series evaluated use of a paracorporeal left ventricle in 17 calves; the other evaluated biventricular bypass in 11 calves. Module pumps with a seamless blood chamber of polyurethane were used. Pump function and system parameters were controlled by a Sinus VK-2 control system. Assisted perfusion began with the induction of ventricular fibrillation. The experiments showed that left ventricular bypass was an effective method for long-term maintenance of the hemodynamics during fibrillation, leading to certain biochemical corrections and restored electrical activity and myocardial contractile function. The hemodynamic state was maintained at a higher level with biventricular bypass and was accompanied by a greater percentage of restored myocardial function. Uneven restoration of contractile activity in the left and right ventricles points to the need for adequate support of both ventricles.

Adenine Nucleotides↗
PubMed1987

Development of autonomous paracorporeal and implanted artificial heart and circulatory assist systems.

The development of autonomous systems for the artificial heart (AH) and for circulatory assistance (CA) has taken several directions. Studies relating to one direction--the development of paracorporeal and implanted systems based on thermal or electric motors--have been conducted at our institute in two stages, moving from stationary systems to totally implanted systems for long-term use. The development of these systems is described. Improvements in the linear solenoid motor, used in some of the first paracorporeal systems, enabled progress toward the development of implanted CA systems based on a reversing electrohydraulic actuator. Modifications were also made in the control system. Early animal testing of these systems indicated that they could be effective in unburdening the heart cavities during left and right bypasses. Full implantation, however, demanded that the devices have improved forms and dimensions and less weight. Smaller electromechanical systems are being developed, and we are experimenting with ways to increase the overall autonomy of the system. An orthotopic model of an implanted AH is promising. Experiments continue on the use of the body's own skeletal muscles to create a blood pump.

Animals↗
PubMed1987

[Possibilities for cardiac defibrillation using intravascular electrodes].

The efficiency of electric defibrillation of the heart was assessed in 17 experiments where the position of action electrodes varied. It is suggested that intravascular application of one electrode plus extravascular application of the other gives the optimum effect. The duration of unassisted reversible fibrillation averaged 3 minutes.

Animals↗
PubMed1983

Development of methods of assisted circulation with artificial heart ventricles.

A comparative study of two methods of bypassing the heart with artificial ventricles (AV) was conducted: left atrium-aorta and left ventricle-aorta. The following factors permit left ventricular bypass to compete successfully with left ventricle-aorta bypass: creation of perfected pumps with low input impedance, use of materials with high resistance to thrombus formation for preparation of the AV and main connecting lines, and development of optimum methods of anticoagulant, disaggregation, and cardiac therapy so that there is no danger of thrombosis and hemorrhage, either experimentally or clinically. Thrombosis was the primary cause of death in only one case in a series of experiments on 15 calves with AV connected according to the atrium-aorta scheme. The positive changes in hemodynamics were approximately the same with the two methods.

Animals↗
PubMed1983

Assisted circulation in cardiac and respiratory insufficiency.

Intra-aortic counterpulsation with a balloon pump (IABP) was used in 63 patients with cardiogenic shock, heart failure after surgery with artificial circulation, internal lacerations of the myocardium, or unstable angina. It was found that the IABP was most efficient in conditions related to myocardial ischemia. Use of arteriovenous perfusion (in 11 patients) or artificial ventricles is indicated in severe perturbations of the pumping function of the heart. As experience has shown, cardiologic and heart surgery patients usually have multiorgan insufficiency. For this reason, it is necessary to use other artificial organs in complex treatment: artificial lungs, kidneys, livers, etc.

Assisted Circulation↗
PubMed1983

Organization of treatment of patients with cardiac insufficiency of different origin.

Assisted circulation is now used in the treatment of severe forms of heart failure which complicate the course of many diseases. Application of one method of assisted circulation--intra-aortic counterpulsation by a balloon pump in cardiogenic shock--was successful: prolonged survival (over 1 year) was obtained in 18% of the patients. A further decrease in the mortality rate is dependent on the rational organization of treatment for these patients. This poses two major problems: the organization of treatment of patients in cardiogenic shock and postoperative heart failure in large cardiologic and heart surgery centers, and treatment of heart failure in patients in whom it has occurred secondarily. We developed a method of organizing the treatment of these patients beginning in the prehospital stage and continuing in a specialized hospital. In addition to methods of assisted circulation, various intensive care methods and hemosorption (in poisoning by liver toxins), hemodialysis (in anuria), etc., are used. Although this type of organization complicates therapy, the results are significantly improved.

Heart Failure↗
PubMed1983

[Experimental and clinical use of artificial heart ventricles].

The paper sums up experience with the development of a domestic system for auxiliary circulation and a module-type artificial ventricle, and presents the results of their experimental trial and first-ever clinical use in patients with severe heart failure following open-heart surgery. Good operational characteristics and high efficiency of this equipment in clinical as well as experimental terms are demonstrated.

Adult↗