Biomedical subjects
Publications and source records attributed to V M Grinval'd.
The paper describes the test specimen of an apparatus for performing hemodialysis and ultrafiltration using biologically active dialysates. The designed test specimen may serve as a technical base for further investigations and optimization of hemodialysis using a biologically active dialysate.
The paper deals with hemodialysis equipment as a constituent of the bioengineering system for artificial blood purification. This approach allows us to objectively evaluate its functional capacities and the usefulness of objective results of hemodialysis and to provide scientific evidence for the structure of hemodialysis equipment. The artificial purification of the biological organism is presented as a variety of interrelated controlling and diagnostic processes in the controlling and actuating elements of extracorporeal artificial organs.
By taking into account the general principles in the design of extrarenal blood clearance apparatuses, all existing hemodialysis apparatuses (HDAs) are classified by the transportation of the controlling medium, by the degree of automation, by the control of amounts of the liquid removed from the patient, and by their connection to the latter. The proposed classification of HDAs and a model of the structure of dialysate units showed the unity of principles in designing HDAs irrespective of the specific features of their design, which may be used to ensure the versatility, reproducibility, technological effectiveness, convenience in application, and efficiency of the apparatuses designed.
Controlled removal of the present quantities of renal metabolites from the waste dialysate can be effected by electrochemical regeneration of the worked-out dialysate, which is based on the use of a dialyzing solution electrolyzer (DSE). A theoretical rationale for DSE functioning modes has been provided. A reaction model of urea oxidation on bimetallic titanium-platinum electrodes has been drawn up. A procedure for calculating the basic technical data of DSE is proposed. The paper presents the design and experimental findings of a 4-section monopolar electrolyzer with electrode parallel-series connection that ensures discrete control of the electrolyzer's anode current provided that the preset anode current density is preserved.
Radical improvements in the physiological features and self-sufficiency of hemodialysis equipment, an essential reduction of the volume of dialyzate contacting with patient's body and elimination of dependence of the equipment operation on the availability of a water-supply network can be ensured by applying a regime of circulation of a relatively small volume (3-5 l) of dialyzate through the regenerating device. The regeneration unit must eliminate the organic products of dialysis from the dialyzate and stabilize the ionic composition of the purified dialyzate according to the preset parameters. Modern methods and technical means for regenerating the used dialyzate are discussed; a regeneration unit, which ensures an electrochemical oxidation (in the used dialyzate) of nitrogen-containing organic metabolites with a subsequent sorption-type additional purification of electrochemically-processed dialyzate, is offered. The regeneration unit is made up of an electrolyser, a sorption-type additional-purification device and a gas utilizer; it eliminates organic metabolites, phosphorus, calcium and potassium from the used dialyzate and stabilizes the pH solution.
Some aspects related with research and development of a key functional unit of the hemodilysis apparatus with the electrochemical regeneration of dialyzate, i.e. the electrochemical oxidation unit which enables a regulated electrochemical oxidation of the main organic hemodilysis products in the waste dialyzate, are described.
The results of a study of parameters of an experimental dialyzate regeneration unit (a key functional unit of a hemodialysis apparatus with the regeneration of dialyzing solution) are discussed in the article.
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According to generalized designs and technologies of devices used for extracorporeal blood transport in artificial purification and with due respect to their clinical usage, the modern perfusion systems, whose elements of hemodialysis units, can be classified by: a method of connecting them to the cardiovascular system of the patient, a type of perfusion pumps that are in use, and a technique regulating the extracorporeal perfusion velocity and the pressure at the exchanger inlet. The suggested classifications, structure models and results of research of the functional and technical parameters of perfusion systems showed their unified design principles irrespective of construction peculiarities, which can ensure the unified, reproductive, technological, simple and efficient application of the apparatuses now at the stage of creation.
On the basis of generalizing the principles of construction and of technical implementation of the extracorporeal blood-transport devices applied in artificial purification, which were described in the 1st part of the paper, mathematical models are suggested to calculate the stroke volume and the consumption of 2-roller perfusion pumps now used in hemodialysis. The above models were made use of to study the influence of the constructive and operational characteristics per consumption originated by the mentioned pumps.
Herein the decentralised microprocessor system is being considered. It allows one to perform automatic regulation in each module of the unit, to make measurements and control of the parameters, visualising the information on the linear display, digital quantitative estimation of the parameters, manual and automatic changing of the set and controlled means of the parameters, alarms, dialogue mode functioning.
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