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US4009709A Expired / Lapsed US ⏱️ 0.0 years remaining

Apparatus and process for determining systolic pressure

Assignee: Baxter International Inc
•
Filing: 1975-05-15
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Granted: 1977-03-01
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Expires: 1995-05-15
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Abstract

Abstract A conventional pressure cuff is attached to a living test subject. First means are provided for changing pressure in the cuff and thereby applying pressure to the subject. Second means communicating with the cuff are provided for measuring a quantity proportional to a time-dependent fluctuating component representative of pulsatile pressure within a blood vessel of the subject, the second means having a frequency response of at least about five times the subject's pulse rate, whereby the fluctuating quantity is proportional to amplitude of pulsatile pressure. The maximum value of the fluctuating quantity is determined as applied cuff pressure is changed. Third means are provided for determining when the fluctuating quantity is about one-half its maximum value for applied cuff pressure greater than the pressure applied when the maximum value occurred or resulted. Systolic pressure, which is equal to applied cuff pressure when the fluctuating quantity is about equal to one-half the maximum value of the fluctuating quantity, is then read out on suitable instrumentation.

Inventors

  • 👤 William Trevor Link
  • 👤 Henry Ferdinand Rugge
  • 👤 William David Jansen

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-23 03:46
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/02; A61B5/021; A61B5/022; A61B5/02225

Claims Analysis

Total Claims: 19
Claim 1
Independent Claim 175 words
An apparatus for determining systolic pressure, comprising: a pressure cuff attachable to a living test subject adjacent a blood vessel; means for changing pressure in the cuff and thereby applying pressure to the subject; means communicating with said cuff for measuring a quantity proportional to a time-dependent fluctuating component representative of the pulsatile pressure within the blood vessel, said means having a frequency response of at least about five times the pulse rate of the subject whereby said quantity is proportional to the amplitude of said pulsatile pressure; means for determining the maximum value attained by said quantity as the applied pressure is changed; means for storing a representation of said maximum value; means for determining when said quantity is substantially equal to about one-half of said maximum value for an applied pressure greater than the pressure applied when said maximum value results; and means for reading out applied pressure corresponding to said quantity being substantially equal to about one-half of said maximum value, said read-out pressure corresponding to the systolic pressure of said subject.
Claim 2
Independent Claim 175 words
An apparatus for determining systolic pressure, comprising: a pressure cuff attachable to a living test subject adjacent a blood vessel; means for changing pressure in the cuff and thereby applying pressure to the subject; means communicating with said cuff for measuring a quantity proportional to a time-dependent fluctuating component representative of the pulsatile pressure within the blood vessel, said means having a frequency response of at least about five times the pulse rate of the subject whereby said quantity is proportional to the amplitude of said pulsatile pressure; means for determining the maximum value attained by said quantity as the applied pressure is changed; means for storing a representation of said maximum value; means for determining when said quantity is substantially equal to about one-half of said maximum value for an applied pressure greater than the pressure applied when said maximum value results; and means for reading out applied pressure corresponding to said quantity being substantially equal to about one-half of said maximum value, said read-out pressure corresponding to the systolic pressure of said subject.
Claim 3
Dependent Claim 23 words
An apparatus as in claim 1, wherein said quantity-measuring means comprises a pressure-transducer having a frequency response of at least about 10 Hertz.
Claim 4
Dependent Claim 31 words
An apparatus as in claim 2, wherein said pressure-changing means comprises a pump which applies an increasing pressure to said cuff between lower and upper pressure limits in a repetitive manner.
Claim 5
Dependent Claim 25 words
An apparatus as in claim 3, including means for stopping said pump and means for bleeding said cuff as said read-out of systolic pressure occurs.
Claim 6
Dependent Claim 71 words
An apparatus as in claim 4, wherein said means for determining said maximum value compreses a comparator wherein each successive representation of the value of said quantity is compared with a tentative previous representation of a maximum value thereof stored in said storing means, the lesser of the compared representations of the values of said quantity is discarded and the greater of the compared representations is stored in said storing means.
Claim 7
Dependent Claim 84 words
An apparatus as in claim 5, wherein said means for determining when said quantity is substantially equal to about one-half of said maximum value comprises a comparator wherein each successive representation of the value of said quantity is compared with one-half of the tentative representation of the maximum value of said quantity stored in said storing means, said stopping means and said bleeding means being activated when a value of said quantity is less than or equal to about one-half of said maximum value.
Claim 8
Dependent Claim 56 words
An apparatus as in claim 6, including a memory unit which temporarily stores a value of the applied pressure corresponding to each successive representation of the value of said quantity and also temporarily stores at least a value of the applied pressure corresponding to the previous to each successive representation of the value of said quantity.
Claim 9
Dependent Claim 52 words
An apparatus as in claim 7, including means for interpolating between stored values of representations of said quantity and between temporarily-stored values of the respective corresponding applied pressure to calculate an interpolated value of the applied pressure corresponding to when said quantity is substantially equal to about one-half of said maximum value.
Claim 10
Dependent Claim 168 words
A process for determining systolic pressure, comprising: changing the pressure in a pressure cuff attached to a living test subject adjacent a blood vessel so as to apply different pressure to the subject; measuring at said cuff with a measuring device having a frequency response of at least about five times the pulse rate of the subject at said cuff, a quantity proportional to a time-dependent fluctuating component representative of the pulsatile pressure within the blood vessel, said quantity being proportional to the amplitude of said pulsatile pressure; determining the maximum value attained by said quantity as the applied pressure is changed; storing a representation of said maximum value; determining when said quantity is substantially equal to about one-half of said maximum value for an applied pressure greater than the pressure applied when said maximum value results; and reading out the applied pressure corresponding to said quantity being substantially equal to about one-half of said maximum value, said read-out pressure corresponding to the systolic pressure of said subject.
Claim 11
Dependent Claim 168 words
A process for determining systolic pressure, comprising: changing the pressure in a pressure cuff attached to a living test subject adjacent a blood vessel so as to apply different pressure to the subject; measuring at said cuff with a measuring device having a frequency response of at least about five times the pulse rate of the subject at said cuff, a quantity proportional to a time-dependent fluctuating component representative of the pulsatile pressure within the blood vessel, said quantity being proportional to the amplitude of said pulsatile pressure; determining the maximum value attained by said quantity as the applied pressure is changed; storing a representation of said maximum value; determining when said quantity is substantially equal to about one-half of said maximum value for an applied pressure greater than the pressure applied when said maximum value results; and reading out the applied pressure corresponding to said quantity being substantially equal to about one-half of said maximum value, said read-out pressure corresponding to the systolic pressure of said subject.
Claim 12
Dependent Claim 25 words
A process as in claim 9, wherein said quantity is measured utilizing a pressure transducer having a frequency response of at least about 10 Hertz.
Claim 13
Dependent Claim 12 words
A process as in claim 10, wherein said pressure is sequentially increased.
Claim 14
Dependent Claim 21 words
A process as in claim 11, including stopping said pump and bleeding said cuff as said read-out of systolic pressure occurs.
Claim 15
Dependent Claim 53 words
A process as in claim 12, including the step of interpolating between stored values of representations of said quantity and between temporarily-stored values of the respective corresponding applied pressure to calculate an interpolated value of the applied pressure corresponding to when said quantity is substantially equal to about one-half of said maximum value.
Claim 16
Dependent Claim 157 words
An automatic blood pressure monitoring system for measuring and monitoring systolic blood pressure of a person comprising: transducer means in pressure-communication with said person for converting said person's blood pressure to a varying electrical analog signal; pump means for applying a controllably variable pressure to said transducer means; said transducer means including cuff means for applying said controllably variable pressure to a blood vessel of said subject; converter means for receiving said electrical analog signal and converting said electrical analog signal to a digital signal; digital processing means adapted to receive said digital signal for determining (1) maximum blood pressure of said person and a first value of said controllably variable pressure corresponding thereto, (2) one-half said maximum blood pressure when occurring at a second value of said controllably variable pressure higher than said first value, and (3) the magnitude of said second value; and means for providing read-out of said second value as systolic blood pressure.
Claim 17
Dependent Claim 157 words
An automatic blood pressure monitoring system for measuring and monitoring systolic blood pressure of a person comprising: transducer means in pressure-communication with said person for converting said person's blood pressure to a varying electrical analog signal; pump means for applying a controllably variable pressure to said transducer means; said transducer means including cuff means for applying said controllably variable pressure to a blood vessel of said subject; converter means for receiving said electrical analog signal and converting said electrical analog signal to a digital signal; digital processing means adapted to receive said digital signal for determining (1) maximum blood pressure of said person and a first value of said controllably variable pressure corresponding thereto, (2) one-half said maximum blood pressure when occurring at a second value of said controllably variable pressure higher than said first value, and (3) the magnitude of said second value; and means for providing read-out of said second value as systolic blood pressure.
Claim 18
Independent Claim 121 words
A method for automatically measuring and monitoring systolic blood pressure of a person including the steps of: A. converting said person's blood pressure to a varying electrical analog signal; B. applying a controllably variable pressure to said person in a manner which affects said electrical analog signal; C. converting said affected electrical analog signal to a digital signal; D. digitally processing said signal to provide (1) maximum blood pressure of said person and a first value of said controllably variable pressure corresponding thereto; (2) one-half said maximum blood pressure when occurring at a second value of said controllably variable pressure higher than said first value; and (3) the magnitude of said second value; and E. providing read-out of said second value.
Claim 19
Independent Claim 121 words
A method for automatically measuring and monitoring systolic blood pressure of a person including the steps of: A. converting said person's blood pressure to a varying electrical analog signal; B. applying a controllably variable pressure to said person in a manner which affects said electrical analog signal; C. converting said affected electrical analog signal to a digital signal; D. digitally processing said signal to provide (1) maximum blood pressure of said person and a first value of said controllably variable pressure corresponding thereto; (2) one-half said maximum blood pressure when occurring at a second value of said controllably variable pressure higher than said first value; and (3) the magnitude of said second value; and E. providing read-out of said second value.

References Cited (Backward Citations)

US3227155A Cited
US3903872A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1980-02-29 1980-08-30 1981-03-01 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1984-02-29 1984-08-30 1985-03-01 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1988-02-29 1988-08-30 1989-03-01 $7700.00 Window Closed / Lapsed

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