Pulse-wave propagation time basis blood pressure monitor

A pulse-wave propagation time basis blood pressure monitor comprising:

• a memory for storing information representing a relationship between pulse pressure values and values of a parameter .alpha., said pulse pressure values being derived from data gathered from a number of subjects;
• input means for inputting a blood pressure value of a subject, for calibration;
• pulse pressure computing means for computing a pulse pressure for calibration using said blood pressure value received from said input means;
• time-interval detect reference point detecting means for detecting a time of occurrence of a pulse wave in the aorta of the subject;
• pulse wave detecting means for detecting a pulse wave which appears in a peripheral blood vessel after said pulse wave appears in the aorta;
• pulse-wave propagation time measuring means for measuring pulse wave propagation time from output signals of said time-interval detect reference point detecting means and said pulse wave detecting means, wherein a first measured pulse wave propagation time is used for calibration;
• first computing means for determining the parameter .alpha. which corresponds to said pulse pressure for calibration computed for the subject based upon the information stored in said memory;
• second computing means for determining a parameter .beta. by using said blood pressure value input for calibration, said pulse wave propagation time used for calibration, and the parameter .alpha. determined by said first computing means;
• third computing means for computing a blood pressure value by using another pulse wave propagation time measured by said pulse-wave propagation measuring means, and the parameters .alpha. and .beta.;
• and
• measured data output means for outputting at least one of said blood pressure value and said parameter .alpha..

A pulse-wave propagation time basis blood pressure monitor comprising:

• first input means for inputting at least a patient's height value as patient information;
• second input means for inputting a blood pressure value for calibration;
• time-interval detect reference point detecting means for detecting a time of occurrence of a pulse wave in the aorta of the patient;
• pulse wave detecting means for detecting a pulse wave which appears in a peripheral blood vessel after said pulse wave appears in the aorta;
• pulse-wave propagation time measuring means for measuring pulse wave propagation time, at a supine position and at one of a sitting and standing position, from output signals of said time-interval detect reference point detecting means and said pulse wave detecting means, wherein a first measured pulse wave propagation time in one of said supine position, said sitting position and said standing position is used for calibration;
• first computing means for computing a change .DELTA.T of said pulse wave propagation time at a time of postural change by using a pulse wave propagation time for calibration measured at said supine position and a pulse wave propagation time for calibration measured at said one of a sitting position and a standing position;
• second computing means for computing a change .DELTA.P of a hydrostatic pressure between the heart and a pulse wave measuring position at the time of postural change, by using the patient's height as patient information;
• third computing means for determining a parameter .alpha. by using said change .DELTA.T of said pulse wave propagation time and said change .DELTA.P of the hydrostatic pressure;
• fourth computing means for determining a parameter .beta. by using said blood pressure value input for calibration, said pulse wave propagation time used for calibration, and the parameter .alpha. determined by said third computing means;
• fifth computing means for computing a blood pressure value by using another pulse wave propagation time measured by said pulse-wave propagation time measuring means, and the parameters .alpha. and .beta.;
• and
• measured data output means for outputting at least one of said blood pressure value, said parameter .alpha. and said parameter .beta..

A method for measuring blood pressure using a pulse-wave propagation time basis blood pressure monitor comprising the steps of:

• storing information describing the relationship between pulse wave propagation times and values of a parameter .alpha. in a memory, each of said pulse wave propagation times being derived from data gathered from a number of subjects;
• inputting a blood pressure value of a subject for calibration;
• detecting a reference point for detecting a time of occurrence of a pulse wave in the aorta of the subject;
• detecting a pulse wave which appears in a peripheral blood vessel after said pulse wave appears in the aorta;
• measuring a pulse wave propagation time from said reference point and said pulse wave which appears in the peripheral blood vessel for calibration;
• determining the parameter .alpha. proper to the subject based upon the information stored in said memory corresponding to said pulse wave propagation time for calibration gathered from the subject;
• determining a parameter .beta. by using said blood pressure value input for calibration, said pulse wave propagation time for calibration, and the parameter .alpha.;
• measuring a second propagation time of another pulse wave into the peripheral blood vessel;
• computing a blood pressure value in accordance with said second pulse wave propagation time, and the parameters .alpha. and .beta.;
• and
• outputting at least one of said blood pressure value, said parameter .alpha. and said parameter .beta..

A method for measuring blood pressure using a pulse-wave propagation time basis blood pressure monitor, comprising the steps of:

• storing information describing the relationship between pulse pressure values and values of a parameter .alpha. in a memory, said pulse pressure values being derived from data gathered from a number of subjects;
• inputting a blood pressure value of the subject for calibration;
• computing a pulse pressure for calibration using said blood pressure value;
• detecting a reference point for detecting a time of occurrence of a pulse wave in the aorta of the subject;
• detecting a pulse wave which appears in a peripheral blood vessel after said pulse wave appears in the aorta;
• measuring a pulse wave propagation time from said time of occurrence of said pulse wave in the aorta of the subject and said pulse wave of said peripheral blood vessel;
• determining the parameter .alpha. proper to the subject based upon the information stored in said memory corresponding to said pulse pressure for calibration gathered from the subject;
• determining a parameter .beta. by using said blood pressure value input for calibration, said pulse wave propagation time and the parameter .alpha.;
• measuring a second propagation time of another pulse wave into the peripheral blood vessel;
• computing a blood pressure value by using said second pulse wave propagation time, and the parameters .alpha. and .beta.;
• and
• outputting at least one of said blood pressure value, said parameter .alpha. and said parameter .beta..