Technique for obtaining the mean blood pressure constant for an individual's blood pressure

• US 4,727,884 A
• Filed: 06/10/1987
• Issued: 03/01/1988
• Est. Priority Date: 05/28/1986
• Status: Expired due to Fees

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: William T. Link
• Inventors: Link, William T.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Sykes, Angela D.
• Application Number:
  US07/060,666
• Time in Patent Office: 265 Days
• Field of Search: 128/672, 128/677, 128/680-683
• US Class Current: 600/494
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 takes precedence
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/02225 using the oscillometric method

Abstract

A non-invasive technique for approximating the mean pressure value and blood pressure constant associated with the actual blood pressure in a particular artery of a given subject is disclosed herein. In accordance with this technique, a number of cuff pulses at varying cuff pressures are generated from the actual blood pressure of the subject and the mean value of the cuff pulse having a maximum peak to peak amplitude value is determined. This mean value is utilized as an approximation of the mean value of the patient'"'"'s actual blood pressure and is also used in combination with the patient'"'"'s diastolic and systolic blood pressures to provide the approximation of the patient'"'"'s blood pressure constant.

Claims

1. A non-invasive method of approximating at least one specific parameter associated with the actual blood pressure pulse in a particular artery of a given subject, which parameter is the mean blood pressure P.sub.(b) M of said subject, said method comprising the steps of:

(a) by non-invasive means, generating a particular cuff pulse from said actual blood pressure pulse by

(i) placing blood pressure cuff means adjacent said particular artery of said subject, and

(ii) pressurizing said cuff means to a number of different pressure levels including a specific level and generating from said different pressure levels cuff pulses having peak to peak amplitude values corresponding to and dependent on said different pressure levels, said specific pressure level being one which corresponds to the cuff pulse having a maximum peak to peak amplitude value, said last-mentioned cuff pulse serving as said particular cuff pulse;

(b) determining the mean value under said particular cuff pulse by integrating said particular cuff pulse and solving for the equations ##EQU6## where P_c (M) is said mean value, T is the duration in time of said cuff pulse, P_c is the cuff pulse pressure amplitude, P_c (D) and P_c (S) are the minimum and maximum pressures, respectively, of the cuff pulse, K_b is the subject'"'"'s blood pressure constant and K_c is the cuff pressure constant of said cuff pulse;

(c) by non-invasive means, determining the diastolic and systolic pressure points P_b (D) and P_b (S), respectively, of said actual blood pressure pulse; and

(d) using the blood pressure constant K_b of said subject, and said diastolic and systolic pressure points P_b (D) and P_b (S), calculating the subject'"'"'s mean blood pressure value P_b (M) by solving the equation

space="preserve" listing-type="equation">P.sub.b (M)=P.sub.b (D)+K.sub.b (P.sub.b (S)-P.sub.b (D)).

2. A non-invasive method of approximating at least one specific parameter associated with the actual blood pressure pulse in a particular artery of a given subject, which parameter is the mean blood pressure P.sub.(b) M of said subject, said method comprising the steps of:

(a) by non-invasive means, generating a group of particular cuff pulses from said actual blood pressure pulse by

(i) placing blood pressure cuff means adjacent said particular artery of said subject, and

(ii) pressurizing said cuff means to a number of different pressure levels including specific levels and generating from said different pressure levels cuff pulses having peak to peak amplitude values corresponding to and dependent on said different pressure levels, said specific pressure levels being ones which correspond to cuff pulses having maximum peak to peak amplitude values as compared to the rest of the cuff pulses, said last-mentioned cuff pulses serving as said particular cuff pulses;

(b) determining the mean value under each of said particular cuff pulses by integrating each of said particular cuff pulses and solving for the equations ##EQU7## where P_c (M) is said mean value, T is the duration in time of said cuff pulse, P_c is the cuff pulse pressure amplitude, P_c (D) and P_c (S) are the minimum and maximum pressures, respectively, of the cuff pulse, K_b is the subject'"'"'s blood pressure constant and K_c is the cuff pressure constant of said cuff pulse;

(c) averaging the mean values P_c (M) for all of said particular cuff pulses to provide an average mean value;

(d) by non-invasive means, determining the diastolic and systolic pressure points P_b (D) and P_b (S), respectively, of said actual blood pressure pulse; and

(e) using the blood pressure constant K_b of said subject, and said diastolic and systolic pressure points P_b (D) and P_b (S), calculating the subject'"'"'s mean blood pressure value P_b (M) by solving the equation

space="preserve" listing-type="equation">P.sub.b (M)=P.sub.b (D)+K.sub.b (P.sub.b (S)-P.sub.b (D)).

3. A method according to claim 2 wherein said particular cuff pulses consist of three cuff pulses, one having a maximum peak to peak amplitude level and the other two having peak to peak amplitudes which have the second and third largest peak to peak levels.

4. A non-invasive apparatus for approximating at least one specific parameter associated with the actual blood pressure pulse in a particular artery of a given subject, which parameter is the mean blood pressure P.sub.(b) M of said subject, said apparatus comprising:

(a) non-invasive means for generating a particular cuff pulse from said actual blood pressure pulse including

(i) blood pressure cuff means positionable adjacent said particular artery of said subject, and

(ii) means for pressurizing said cuff means to a number of different pressure levels including a specific level and generating from said different pressure levels cuff pulses having peak to peak amplitude values corresponding to and dependent on said different pressure levels, said specific pressure level being one which corresponds to the cuff pulse having a maximum peak to peak amplitude value, said last-mentioned cuff pulse serving as said particular cuff pulse;

(b) means for determining the mean value under said cuff pulse by integrating said cuff pulse and solving for the equations ##EQU8## where P_c (M) is said mean value, T is the duration in time of said cuff pulse, P_c is the cuff pulse pressure amplitude, P_c (D) and P_c (S) are the minimum and maximum pressures, respectively, of the cuff pulse, K_b is the subject'"'"'s blood pressure constant and K_c is the cuff pressure constant of said cuff pulse;

(c) non-invasive means for determining the diastolic and systolic pressure points P_b (D) and P_b (S), respectively, of said actual blood pressure pulse; and

(d) means using the blood pressure constant K_b of said subject, and said diastolic and systolic pressure points P_b (D) and P_b (S), for calculating the subject'"'"'s mean blood pressure value P_b (M) by solving the equation

space="preserve" listing-type="equation">P.sub.b (M)=P.sub.b (D)+K.sub.b (P.sub.b (S)-P.sub.b (D)).

5. A non-invasive apparatus for approximating at least one specific parameter associated with the actual blood pressure pulse in a particular artery of a given subject, which parameter is the mean blood pressure P.sub.(b) M of said subject, said apparatus comprising:

(a) non-invasive means for generating a group of particular cuff pulses from said actual blood pressure pulse by

(i) blood pressure cuff means positionable adjacent said particular artery of said subject, and

(ii) means for pressurizing said cuff means to a number of different pressure levels including specific levels and generating from said different pressure levels cuff pulses having peak to peak amplitude values corresponding to and dependent on said different pressure levels, said specific pressure levels being ones which correspond to cuff pulses having maximum peak to peak amplitude values as compared to the rest of the cuff pulses, said last-mentioned cuff pulses serving as said particular cuff pulses;

(b) means for determining the mean value under each of said particular cuff pulses by integrating each of said particular cuff pulses and solving for the equations ##EQU9## where P_c (M) is said mean value, T is the duration in time of said cuff pulse, P_c is the cuff pulse pressure amplitude, P_c (D) and P_c (S) are the minimum and maximum pressures, respectively, of the cuff pulse, K_b is the subject'"'"'s blood pressure constant and K_c is the cuff pressure constant of said cuff pulse;

(c) averaging the mean values P_c (M) for all of said particular cuff pulses to provide an average mean value;

(d) non-invasive means for determining the diastolic and systolic pressure points P_b (D) and P_b (S), respectively, of said actual blood pressure pulse; and

(e) means using the blood pressure constant K_b of said subject, and said diastolic and systolic pressure points P_b (D) and P_b (S), for calculating the subject'"'"'s mean blood pressure value P_b (M) by solving the equation

space="preserve" listing-type="equation">P.sub.b (M)=P.sub.b (D)+K.sub.b (P.sub.b (S)-P.sub.b (D)).

6. An apparatus according to claim 5 wherein said particular cuff pulses consist of three cuff pulses, one having a maximum peak to peak amplitude level and the other two having peak to peak amplitudes which have the second and third largest peak to peak levels.

7. A non-invasive method of approximating at least one specific parameter associated with the actual blood pressure pulse in a particular artery of a given subject, which parameter is the mean blood pressure of said subject, said method comprising the steps of:

(a) by non-invasive means, generating a particular cuff pulse from said actual blood pressure pulse by

(i) placing blood pressure cuff means adjacent said particular artery of said subject, and

(ii) pressurizing said cuff means to a number of different pressure levels including a specific level and generating from said different pressure levels cuff pulses having peak to peak amplitude values corresponding to and dependent on said different pressure levels, said specific pressure level being one which corresponds to the cuff pulse having a maximum peak to peak amplitude value, said last-mentioned cuff pulse serving as said particular cuff pulse;

(b) determining the mean value under said particular cuff pulse and the minimum and maximum pressures of said particular cuff pulse;

(c) by non-invasive means, determining the diastolic and systolic pressure points, respectively, of said actual blood pressure pulse; and

(d) using said mean value under said cuff pulse, its minimum and maximum pressures and the diastolic and systolic pressure points of said actual blood pressure pulse, deriving the mean blood pressure of said subject.

8. A non-invasive apparatus for approximating at least one specific parameter associated with the actual blood pressure pulse in a particular artery of a given subject, which parameter is the mean blood pressure of said subject, said apparatus comprising:

(a) non-invasive means for generating a particular cuff pulse from said actual blood pressure pulse including

(i) blood pressure cuff means positionable adjacent said particular artery of said subject, and

(ii) means for pressurizing said cuff means to a number of different pressure levels including a specific level and generating from said different pressure levels cuff pulses having peak to peak amplitude values corresponding to and dependent on said different pressure levels, said specific pressure level being one which corresponds to the cuff pulse having a maximum peak to peak amplitude value, said last-mentioned cuff pulse serving as said particular cuff pulse;

(b) means for determining the mean value under said particular cuff pulse and the minimum and maximum pressures of said particular cuff pulse;

(c) non-invasive means for determining the diastolic and systolic pressure points, respectively, of said actual blood pressure pulse; and

(d) means using said mean value under said cuff pulse, its minimum and maximum pressures and the diastolic and systolic pressure points of said actual blood pressure pulse for deriving the mean blood pressure of said subject.

9. A non-invasive method of approximating at least one specific parameter associated with the actual blood pressure pulse in a particular artery of a given subject, which parameter is the mean blood pressure of said subject, said method comprising the steps of:

(a) by non-invasive means, generating a particular group of cuff pulses from said actual blood pressure pulse by

(i) placing blood pressure cuff means adjacent said particular artery of said subject, and

(ii) pressurizing said cuff means to a number of different pressure levels including specific levels and generating from said different pressure levels cuff pulses having peak to peak amplitude values corresponding to and dependent on said different pressure levels, said specific pressure levels being ones which correspond to cuff pulses having maximum peak to peak amplitude value, said last-mentioned cuff pulses serving as said particular cuff pulses;

(b) determining the mean value under each of said particular cuff pulses and the minimum and maximum pressures of said particular cuff pulses;

(c) by non-invasive means, determining the diastolic and systolic pressure points, respectively, of said actual blood pressure pulse; and

(d) using said mean value under each of said cuff pulses, their respective minimum and maximum pressures and the diastolic and systolic pressure points of said actual blood pressure pulse, deriving the mean blood pressure of said subject.