Surgery – Diagnostic testing – Cardiovascular
Reexamination Certificate
2002-04-17
2004-05-25
Nasser, Robert L. (Department: 3736)
Surgery
Diagnostic testing
Cardiovascular
C600S300000, C600S501000
Reexamination Certificate
active
06740045
ABSTRACT:
Japanese Patent Application No. 2001-121583 filed on Apr. 19, 2001, is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
The present invention relates to a central blood pressure waveform estimation device and a peripheral blood pressure waveform detection device.
A central blood pressure, specifically, a blood pressure and a blood pressure waveform in the origin of the aorta can be important information for treatment policy planning, post-operative or post-treatment management, intensity management in ergotherapy, and the like for patients suffering from a heart disease. However, it is difficult to non-invasively measure the central blood pressure. In particular, it is very difficult to measure the central blood pressure when the patient takes exercise or the like. Because of this, the central blood pressure and the blood pressure waveform are not generally utilized in clinical applications.
The blood pressure waveform in the peripheral vessel is considered to be the central blood pressure waveform changed by transmission characteristics of a tube through which the pressure wave is transmitted. Based on this idea, it is known in the art that the central blood pressure waveform can be derived from the pressure pulse waveform in the peripheral artery with high precision using a transfer function measured in advance between the blood pressure waveform in the origin of the aorta and the blood pressure waveform in the peripheral artery such as the brachial artery or the radial artery, specifically, the pressure pulse waveform.
It is also known in the art that the pressure pulse wave in the peripheral artery such as the radial artery can be non-invasively detected with high precision using applanation tonometry which measures the pressure using a pressure sensor pressed against the artery so that part of the blood vessel wall is flattened.
Details of these studies are described in
McDonald's Blood Flow in Arteries—Theoretical, Experimental and Clinical Principles
(Fourth Edition), Chapter 22, by W. W. Nichols and M. F. O'Rourke.
However, it is necessary to measure the pulse wave while allowing the person being measured to be in a resting state in order to stably detect the pulse wave in the peripheral artery such as the radial artery using applanation tonometry or the like.
Moreover, since only one transfer function is used to derive the blood pressure waveform in the aorta from the pulse wave in the peripheral artery regardless of the age and state of the subject, it may be difficult to maintain precision of the blood pressure waveform in the aorta to be derived.
BRIEF SUMMARY OF THE INVENTION
The present invention has been achieved in view of the above-described problems. The present invention may provide a central blood pressure waveform estimation device exhibiting at least one of the following effects.
(1) A central blood pressure waveform can be derived by using a waveform of a peripheral pulse wave which is non-invasively detected.
(2) A pulse wave in a peripheral artery can be stably detected without forcing a subject to be in a resting state.
(3) A central blood pressure waveform can be derived from a pulse wave in a peripheral artery with high precision regardless of an age or state of an subject.
A central blood pressure waveform estimation device according to a first aspect of the present invention comprises:
a pulse wave detection section which non-invasively detects a peripheral pulse wave;
a transfer function storage section which stores a transfer function calculated in advance based on a waveform of the peripheral pulse wave detected by the pulse wave detection section and a central blood pressure waveform corresponding to the peripheral pulse waveform; and
a central blood pressure waveform calculation section which calculates a central blood pressure waveform corresponding to a waveform of a peripheral pulse wave newly detected by the pulse wave detection section, based on the newly-detected peripheral pulse waveform and the transfer function.
According to the first aspect of the present invention, a central blood pressure waveform, specifically, a blood pressure waveform in an origin of an aorta can be derived from a peripheral pulse waveform which is non-invasively detected.
A central blood pressure waveform estimation device according to a second aspect of the present invention comprises:
a pulse wave detection section which non-invasively detects a peripheral pulse wave;
a transfer function storage section which stores a transfer function calculated in advance based on a waveform of the peripheral pulse wave detected previously and a central blood pressure waveform corresponding to the peripheral pulse waveform; and
a central blood pressure waveform calculation section which calculates a central blood pressure waveform corresponding to a waveform of a peripheral pulse wave newly detected by the pulse wave detection section, based on the newly-detected peripheral pulse waveform and the transfer function.
“A waveform of the peripheral pulse wave detected previously” is a waveform of a peripheral pulse wave detected by a device for pulse wave detection formed in the same manner as the above pulse wave detection section, for example.
According to the second aspect of the present invention, a blood pressure waveform in an aorta can be derived from a peripheral pulse waveform which is non-invasively detected.
Moreover, since a transfer function calculated in advance based on a waveform of a peripheral pulse wave detected by a device for pulse wave detection formed in the same manner as the pulse wave detection section of the central blood pressure waveform estimation device is stored in the transfer function storage section, it is unnecessary to calculate a transfer function for each central blood pressure waveform estimation device.
A central blood pressure waveform estimation device according to a third aspect of the present invention comprises:
a pulse wave detection section which non-invasively detects a peripheral pulse wave;
a blood pressure measurement section which measures a blood pressure in an area near a portion in which a peripheral pulse wave is detected by the pulse wave detection section;
a conversion section which converts a waveform of the peripheral pulse wave detected by the pulse wave detection section into a peripheral blood pressure waveform using a value of the blood pressure measured by the blood pressure measurement section;
a transfer function storage section which stores a transfer function calculated in advance based on the peripheral blood pressure waveform obtained by the conversion section and a central blood pressure waveform corresponding to the peripheral blood pressure waveform; and
a central blood pressure waveform calculation section which calculates a central blood pressure waveform corresponding to a peripheral blood pressure waveform obtained by converting a waveform of a pulse wave newly detected by the pulse wave detection section using the conversion section, based on this peripheral blood pressure waveform and the transfer function.
According to the third aspect of the present invention, a blood pressure waveform in an aorta can be derived from a peripheral blood pressure waveform obtained by converting a waveform of a peripheral pulse wave which is non-invasively detected.
A central blood pressure waveform estimation device according to a fourth aspect of the present invention comprises:
a pulse wave detection section which non-invasively detects a peripheral pulse wave;
a blood pressure value storage section which stores a value of a blood pressure measured previously in an area near a portion in which a peripheral pulse wave is detected by the pulse wave detection section;
a conversion section which converts a waveform of the peripheral pulse wave detected by the pulse wave detection section into a peripheral blood pressure waveform using the blood pressure value stored in the blood pressure value storage section;
a transfer function storage section which stores a transfer funct
Mallari Patricia C
Nasser Robert L.
Oliff & Berridg,e PLC
Seiko Epson Corporation
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