Vascular impedance measurement instrument

• US 6,290,651 B1
• Filed: 04/10/2000
• Issued: 09/18/2001
• Est. Priority Date: 12/28/1990
• Status: Expired due to Term

• Current Assignee: Hypertension Diagnostics, Inc.
• Original Assignee: Hypertension Diagnostics, Inc.
• Inventors: Cohn, Jay N., Finkelstein, Stanley M., Chesney, Charles F.
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US09/545,946
• Time in Patent Office: 526 Days
• Field of Search: 600/483, 600/481, 600/504, 600/526, 600/485, 128/920
• US Class Current: 600/485
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: G09B 23/28 for medicine
• CPC Class Codes: Y10S 128/92 Computer assisted medical diagnostics

Abstract

A vascular impedance measurement instrument includes a transducer to obtain a digitized arterial blood pressure waveform. The digitized data is used to determine cardiac output, and to subsequently obtain measurements of impedance parameters using the modified Windkessel model of the arterial system. The instrument is used as an aid in diagnosing, treating and monitoring patients with cardiovascular disease.

Claims

1. A vascular impedance measurement instrument, comprising:

means for measuring an arterial blood pressure of a patient and producing a corresponding series of digitized data samples representing a waveform of the arterial blood pressure of the patient;

means for determining a mean arterial pressure of the patient from the sample series;

means for determining a cardiac output measurement value for the patient from the sample series and from clinically derived patient data;

means for determining for the patient one or more parameters of a vascular impedance model from the sample series and from the cardiac output value; and

means for displaying the one or more parameters.

3. The instrument according to claim 1, wherein the means for measuring comprises:

a pressure transducer; and

an analog-to-digital converter operatively coupled to receive a signal from the transducer and to output the sample series.

4. The instrument according to claim 1, wherein the one or more parameters of vascular impedance include a measure of compliance of the patient'"'"'s blood vessels.

5. The instrument according to claim 4, wherein the one or more parameters of vascular impedance further include a measure of resistance of the patient'"'"'s blood vessels to the flow of blood.

6. The instrument according to claim 1, wherein the one or more parameters of vascular impedance include a measure of resistance of the patient'"'"'s blood vessels to the flow of blood.

7. The instrument according to claim 1, further comprising:

means for marking a segment of the heart beat signal corresponding to systole; and

means for determining an ejection time by measuring the duration of the segment wherein the determining the cardiac output measurement value is based at least in part on the ejection time.

2. A vascular impedance measurement instrument, comprising:

a sensor that measures an arterial blood pressure of a patient and produces a corresponding series of digitized data samples representing a waveform of the arterial blood pressure of the patient; and

a computer operatively coupled to the sensor and configured to;

determine a mean arterial pressure of the patient from the sample series;

determine a cardiac output value for the patient from the sample series and from clinically derived patient data;

determine for the patient one or more parameters of a vascular impedance model from the sample series and from the cardiac output value; and

output the one or more parameters.

8. The instrument according to claim 2, wherein the sensor comprises:

a pressure transducer; and

an analog-to-digital converter operatively coupled to receive a signal from the transducer and to output the sample series.

9. The instrument according to claim 2, wherein the one or more parameters of vascular impedance include a measure of compliance of the patient'"'"'s blood vessels.

10. The instrument according to claim 9, wherein the one or more parameters of vascular impedance further include a measure of resistance of the patient'"'"'s blood vessels to the flow of blood.

11. The instrument according to claim 2, wherein the one or more parameters of vascular impedance include a measure of resistance of the patient'"'"'s blood vessels to the flow of blood.

12. The instrument according to claim 2, wherein the computer is further configured to mark a segment of the heart beat signal corresponding to systole and determine an ejection time by measuring the duration of the segment, wherein the determination of the cardiac output measurement value is based at least in part on the ejection time.