Methods and apparatus for monitoring cardiac output
First Claim
Patent Images
1. A method for ascertaining the cardiac output of a human patient, said method comprising the steps of:
- measuring the systolic velocity of the blood flowing through the patient'"'"'s descending aorta with an ultrasonic probe inserted in the esophagus of the patient;
determining the cross-sectional area of the patient'"'"'s ascending aorta; and
calculating the patient'"'"'s cardiac output from said systolic velocity and said aortic area.
4 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for ascertaining the cardiac output of a human patient, said method comprising the steps of: measuring the systolic velocity of the blood flowing through the patient'"'"'s descending aorta; determining the cross-sectional area of the patient'"'"'s ascending aorta; and calculating the patient'"'"'s cardiac output from said systolic velocity and said aortic area. The cardiac output can be converted: (1) to cardiac index by dividing it by the patient'"'"'s body surface area, and (2) to systemic vascular resistance by dividing a value representing the patient'"'"'s blood pressure by said cardiac output.
-
Citations
21 Claims
-
1. A method for ascertaining the cardiac output of a human patient, said method comprising the steps of:
- measuring the systolic velocity of the blood flowing through the patient'"'"'s descending aorta with an ultrasonic probe inserted in the esophagus of the patient;
determining the cross-sectional area of the patient'"'"'s ascending aorta; and
calculating the patient'"'"'s cardiac output from said systolic velocity and said aortic area. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- measuring the systolic velocity of the blood flowing through the patient'"'"'s descending aorta with an ultrasonic probe inserted in the esophagus of the patient;
-
8. A method for measuring the cardiac output of a human patient, said method comprising the steps of:
- determining the cross-sectional area of the patient'"'"'s ascending aorta;
generating a signal representative of the systolic velocity of the blood flowing through the patient'"'"'s descending aorta with an ultrasonic probe inserted in the esophagus of the patient;
upwardly scaling that signal from a calibration signal representing a relationship between said systolic velocity representative signal and the velocity of the blood flowing through the patient'"'"'s ascending aorta;
subjecting said first systolic velocity signal to frequency spectrum analysis to produce a multicomponent velocity profile signal;
integrating said velocity profile signal with respect to time to thereby produce a systolic velocity integral;
computing stroke volume as a function of said cross-sectional area and said systolic velocity integral;
summing the stroke volumes thus determined for n beats of the patient'"'"'s heart; and
dividing the resulting sum by the time spanning said n beats.
- determining the cross-sectional area of the patient'"'"'s ascending aorta;
-
9. A method of determining the cardiac index of a human patient which includes the steps of:
- computing the cardiac output of the patient by determining the cross-sectional area of the patient'"'"'s ascending aorta, generating a signal representative of the systolic velocity of the blood flowing through the patient'"'"'s descending aorta with an ultrasonic probe inserted in the esophagus of the patient, upwardly scaling that signal from a calibration signal representing a relationship between said systolic velocity representative signal and the velocity of the blood flowing through patient'"'"'s ascending aorta, subjecting said first systolic velocity signal to frequency spectrum analysis to produce a multicomponent velocity profile signal, integrating said velocity profile signal with respect to time to thereby produce a systolic velocity integral, computing stroke volume as a function of said cross-sectional area and said systolic velocity integral, summing the stroke volumes thus determined for n beats of the patient'"'"'s heart, and dividing the resulting sum by the time spanning said n beats to determine said cardiac output, and dividing the cardiac output of the patient by his body surface area.
-
10. Apparatus for measuring the cardiac output of a human patient, said apparatus including:
- means for measuring the systolic velocity of the blood flowing through the patient'"'"'s aorta, said means including an ultrasonic esophageal probe;
means for calculating the cross-sectional area of the patient'"'"'s aorta from his height, weight, age, sex; and
means for calculating the cardiac output of the patient from the thus determined systolic flow velocity and aortic diameter. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
- means for measuring the systolic velocity of the blood flowing through the patient'"'"'s aorta, said means including an ultrasonic esophageal probe;
-
18. A method for measuring the systemic vascular resistance of a human patient, said method comprising the steps of:
- determining the cross-sectional area of the patient'"'"'s ascending aorta;
generating a signal representative of the systolic velocity of the blood flowing through the patient'"'"'s descending aorta with an ultrasonic probe inserted in the esophagus of the patient;
upwardly scaling that signal from a calibration signal representing a relationship between said systolic velocity representative signal and the velocity of the blood flowing through the patient'"'"'s ascending aorta;
subjecting said first systolic velocity signal to frequency spectrum analysis to produce a multicomponent velocity profile signal;
integrating said velocity profile signal with respect to time to thereby produce a systolic velocity integral;
computing stroke volume as a function of said cross-sectional area and said systolic velocity integral;
summing the stroke volumes thus determined for n beats of the patient'"'"'s heart; and
dividing the resulting sum by a value representing the inverse of the blood pressure of the patient. - View Dependent Claims (19)
- determining the cross-sectional area of the patient'"'"'s ascending aorta;
- 20. A method of determining the cardiac index of a human patient which includes the steps of computing the cardiac output of the patient by determining the cross-sectional area of the patient'"'"'s ascending aorta, generating a signal representative of the systolic velocity of the blood flowing through the patient'"'"'s descending aorta with an ultrasonic probe inserted in the esophagus of the patient, upwardly scaling that signal from a calibration signal representing a relationship between said systolic velocity representative signal and the velocity of the blood flowing through the patient'"'"'s ascending aorta, subjecting said first systolic velocity signal to frequency spectrum analysis to produce a multicomponent velocity profile signal, integrating said velocity profile signal with respect to time to thereby produce a systolic velocity integral, computing stroke volume as a function of said cross-sectional area and said systolic velocity integral, summing the stroke volumes thus determined for n beats of the patient'"'"'s heart, dividing the resulting sum by the time spanning said n beats to determine said cardiac output, and dividing a value representing the inverse of the blood pressure of the patient by the cardiac output of the patient.
Specification