Patent ID: 8591428

Claim:
A method of measuring a blood volume, the method comprising: reading individual specific information of a patient related to oxygen metabolism; calculating an input cardiac output value based on the read individual specific information of the patient; calculating K based on the calculated input cardiac output; acquiring by a biological signal monitoring apparatus a pulse wave propagation time (PWTT), a heart rate (HR) of the patient, and coefficients (α and β) inherent to the patient; and calculating a cardiac output by using an expression of esCO=K·(α·PWTT+β)·HR, where esCO is the cardiac output, wherein the input cardiac output value is calculated by using an expression of CO= a+b ·Sex+ c ·Age+ d ·BSA+ e ·PWTT+ f ·HR·PP where CO is the input cardiac output value; Sex is the sexuality of the patient, when the patient is male, Sex=1, and when the patient is female, Sex=−1; Age is the age of the patient; BSA is the body surface area of the patient; PWTT is the pulse wave propagation time; HR is the heart rate of the patient; PP is a pulse pressure of the patient; and a, b, c, d, e, and f are coefficients inherent to the patient.