Method and apparatus for measuring blood volume, and vital sign monitor using the same

• US 7,402,138 B2
• Filed: 03/31/2005
• Issued: 07/22/2008
• Est. Priority Date: 03/31/2004
• Status: Active Grant

• Current Assignee: Nihon Kohden Corporation
• Original Assignee: Nihon Kohden Corporation
• Inventors: Akiyama, Takeshi, Uchida, Keisuke, Sugo, Yoshihiro, Takeda, Sunao
• Primary Examiner(s): Layno; Carl H.
• Assistant Examiner(s): LEE, YUN H
• Application Number:
  US11/094,228
• Publication Number:
  US 20050222514A1
• Time in Patent Office: 1,209 Days
• Field of Search: 600/526
• US Class Current: 600/526
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence

Abstract

A first member is adapted to measure an electrocardiogram of a patient. A second member is adapted to measure a peripheral pulse wave of the patient. A first calculator calculates a pulse wave propagation time (PWTT) and a heart rate (HR) of the patient based on the electrocardiogram and the peripheral pulse wave. A second calculator calculates a cardiac output (CO) of the patient with an equation of CO=(αK·PWTT+βK)·HR, where α, β and K are coefficients inherent to the patient.

Claims

1. An apparatus for measuring a blood volume, comprising:

a first member, adapted to measure an electrocardiogram of a patient;

a second member, adapted to measure a peripheral pulse wave of the patient;

a first calculator, which calculates a pulse wave propagation time (PWTT) and a heart rate (HR) of the patient based on the electrocardiogram and the peripheral pulse wave; and

a second calculator, which calculates a cardiac output (CO) of the patient with an equation of CO=(α

K·

PWTT+β

K)·

HR, where α

, β and

K are coefficients inherent to the patient.

2. The measuring apparatus as set forth in claim 1, further comprising a third member, adapted to measure a blood pressure of the patient,

wherein at least one of the coefficients is calibrated with a value obtained by the third member.

3. A vital sign monitor incorporating the measuring apparatus as set forth in claim 1, the vital sign monitor comprising a display showing at least the cardiac output.