Surgery – Truss – Pad
Patent
1992-02-11
1994-04-12
Cohen, Lee S.
Surgery
Truss
Pad
128677, 128687, 128686, A61B 500
Patent
active
053016750
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to an apparatus for measuring a blood flow velocity and a blood flow volume of an aorta, specifically an apparatus for detecting a passage of a pulse wave by a cuff put around an upper arm, and, based on this detection result, obtaining a blood flow velocity and a blood flow volume of the aorta.
BACKGROUND ART
For the diagnosis of circulation diseases it is effective to measure the blood flow velocity of an aorta and the blood flow volume thereof in addition to electrocardiogram measurement, blood flow measurement, pulse wave analyses, so on. A method which has been conventionally used for measuring blood flow velocity and blood flow volume of aortas is blood vessel catheter measuring method in which a catheter is inserted into an aorta. In this method, a pair of pressure sensors are attached at a set interval to the leading end of the catheter. The catheter is inserted until its leading end reaches an aorta under X-ray inspection to detect pulse waves as a pressure change by both pressure sensors, whereby a blood flow velocity of the aorta is obtained based on a phase difference of the detected pulse waves. A blood flow volume is given by multiplying a blood flow effective sectional area of the aorta by the blood flow velocity. In a different practiced method, a reagent is poured from the leading end of the catheter to measure a lung circulation time of the reagent, whereby an averaged stroke volume per minute is given.
But these invasive blood vessel catheter measuring methods are large scaled by inserting a catheter into an aorta, which unpreferably much burdens patients physically and mentally. An additional problem is that the measuring apparatus is accordingly expensive and is not easily operable for the measurement and requires special skill. Further another problem of the method in which a reagent is poured is that the poured reagent burdens patients.
DISCLOSURE OF THE INVENTION
An object of this invention is to provide an apparatus for measuring the blood flow velocity and blood flow volume of an aorta by a non invasive and simple method.
A first feature of the present invention relates to an apparatus for measuring a blood flow velocity in an aorta, comprising:
a cuff including three bags of a blood flow shutting bag for shutting a blood flow of an upper arm, a forward detection bag for detecting a pulse wave heading to the blood flow shutting bag, and a rear detection bag for detecting a pulse wave which has cleared the blood flow shutting bag;
pressure control means for retaining a reference internal pressure of the blood flow shutting bag and the respective detection bags at a systolic pressure SP;
a forward sensor for detecting as a forward pulse wave a pressure change generated in the forward detection bag;
a rear sensor for detecting as a rear pulse wave a pressure change generated in the rear detection bag with a delay time SPdt from a detection time of the forward pulse wave;
calculating means for dividing a distance L between the forward detection bag and the rear detection bag by the delay time SPdt to obtain a quotient, and outputting the quotient as a blood flow velocity VH of an aorta in a high pressure period.
A second feature of the present invention relates to an apparatus for measuring a blood flow velocity according to the first feature, in which there is further provided means for obtaining a systolic pressure SP, a diastolic pressure DP, a dicroticnotch pressure DNP, calculating a coefficient R based on Equation R=(SP-DP)/(DNP-DP), calculating a quotient by dividing the blood flow velocity VH in the high pressure period by the coefficient R, and outputting the quotient as a blood flow velocity VL in the aorta in a low pressure period.
A third feature of the present invention relates to an apparatus for measuring a blood flow velocity in an aorta, comprising:
a cuff including three bags of a blood flow shutting bag for shutting a blood flow of an upper arm, a forward detection bag for detecting a pulse wave heading to the blood flow
REFERENCES:
patent: 3908640 (1975-09-01), Page
patent: 4245648 (1981-01-01), Trimmer
patent: 4396018 (1983-08-01), Sibley
Application Ser. No. 521,156, dated Jun. 1991, Tomita.
Cohen Lee S.
Nasser Jr. Robert L.
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