Surgery – Truss – Pad
Patent
1984-12-14
1987-03-24
Howell, Kyle L.
Surgery
Truss
Pad
128682, 128686, A61B 502
Patent
active
046517480
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to medicine and is more particularly concerned with noninvasive methods and devices for determining the state of the cardiovascular system of living organisms by measuring, recording and analyzing the hemodynamic parameters of that system.
PRIOR ART
The state of the cardiovascular system of man and warm-blooded animals depends on a number of factors which include the cardiac action, the state of the blood vessels of different organs, and the nervous regulation of the organism. It is determined through the use of various methods and devices, mostly of the non-invasive type which is the simplest and safest.
There is known a method and device for non-invasive determination of the state of the cardiovascular system of a living organism according to International U.S. Application of Apr. 15, 1982, PCT WO 82/01122, IPC.sup.3 A61B 5/02, 5/05.
This method is based on measuring certain hemodynamic parameters of the cardiovascular system and carried out as follows. Four electrodes of an impedance plethysmograph (rheograph) are attached to a part of a subject's body which has to be investigated. Variable pressure is applied to the artery of another part of the subject's body by varying pneumatic pressure in an occlusion cuff enveloping that part. The rheograph measures the electric resistance of the flow of blood through the blood vessel of the part under investigation and its first derivative when the pneumatic pressure in the cuff, which changes due to the pulsation in the vessel, as at its maximum, minimum, and mean levels. These levels are also measured, and so is the conductivity of the blood. On the basis of formulas known from the theory of hemodynamics and the theory of electric circuits, as well as some information on the subject, such as age, sex, weight, and blood conductivity, the results of the measurements are used to calculate various hemodynamic parameters of the cardiovascular system, including the amount of blood ejected by the heart, the cardiac output, the flowrate of blood in the vessel of the part being investigated, the modulus of elasticity of the wall of that vessel, etc. All these values are recorded and serve to determine the state of the subject's cardiovascular system.
The above method is carried out with the aid of a device comprising an electric resistor and its first time derivative measuring channel, an arterial pressure control and measuring channel, a unit for input of data on a patient, as well as a processor and a display which are placed in series. The outputs of said channels and of the data input unit are connected to respective inputs of the processor. The electric resistor and its first time derivative measuring channel is a rheograph with four electrodes. The arterial pressure control and measuring channel comprises a variable pressure source and an occlusion cuff with a pressure sensor which are connected in series.
The method and device in question are disadvantageous in that they fail to provide for a well-differentiated and trustworthy diagnosis of each diseases of the cardiovascular system as ischemia of the heart, atherosclerosis of peripheral arteries, neurocirculatory asthenia; and some others. This is due to a low accuracy of determining the chosen hemodynamic parameters, which, in turn, is accounted for by great errors in measuring the electric resistance of the blood flow with the aid of a rheograph. Such errors result from external effects, namely, the resistance of the contacts between the electrodes and the patient's body and the resistance of other body tissues.
The above method and device are further disadvantageous in that they do not lend themselves to screening.
There are known a method and device for determining the state of the cardiovascular system of living organisms by measuring the arterial blood pressure according to U.S. Pat. No. 4,140,110 of Feb. 20, 1979, IPC A61B 5/02.
This method consists in applying a growing pressure to a part of a subject's body being investigated, which is done by varying pn
REFERENCES:
patent: 3871359 (1975-03-01), Pacela
patent: 3903872 (1975-09-01), Link
patent: 4140110 (1979-02-01), Jansen et al.
patent: 4245650 (1981-01-01), Welker et al.
Darling, R. C. et al., "Quantitative Segmental Pulse Volume Recorder", Surgery Dec. 1972, vol. 72, No. 6, pp. 873-887.
Excerpts from Biophysical Fundamentals of Blood Circulation and Clinical Methods for . . . , N. N. Savitsky, pp. 141-144, 150, 151, 1974.
Excerpts From Analog-Digital Converters, Gitis et al., pp. 226-228, 1981.
Arterial Oscillograph, USSR Ministry of Health, 1963.
Excerpts From Design of Radioelectronic Equipment Built Around Integrated Circuits, Bakhtiarov et al., pp. 167-168, 1980.
Alexandrov Jury N.
Gaiaktionov Viktor A.
Makarova Inna I.
Ozersky Jury P.
Vinogradov Alexei V.
Fiziko-Tekhnitchesky Institute
Howell Kyle L.
Taworski Francis J.
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