Method for using a pulse oximetry signal to monitor blood pressure
First Claim
1. A system for continuously monitoring the blood pressure of a patient for an extended period of time which comprises:
- a unit for measuring blood pressures in an artery of the patient during a measurement cycle, wherein the measurement cycle has a beginning and an end, and wherein a systolic pressure (psystolic) is measured at a time “
t0”
at the beginning of the measurement cycle and a diastolic pressure (pdiastolic) is measured at the end of the measurement cycle;
a device for detecting blood pressure pulses in the cardio-vasculature of a patient during the measurement cycle, wherein a first pulse near the beginning of the measurement cycle has an amplitude value “
V1”
, and a second pulse with an amplitude value “
V2”
is detected at the end of the measurement cycle wherein V1 is detected by the detecting device and a first pressure p1 is measured by the measuring unit at a determined time (“
t1”
) in the measurement cycle, and wherein an initial pressure drop Δ
1 is established at the time t1, with Δ
1 being a correction factor equal to the difference between psystolic and p1 (Δ
1=psystolic−
p1); and
a computer for correlating the systolic pressure (psystolic) with “
V2+Δ
1”
, to establish a correlation therebetween, and for thereafter using the correlation to identify variations in pulse amplitudes V2 detected by the detecting device as indications of corresponding variations in systolic pressures (psystolic) during the extended period of time following the measurement cycle.
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Abstract
A system for continuously monitoring the blood pressure of a patient over an extended time interval requires using a blood pressure measuring unit (e.g. a sphygmomanometer) to calibrate an oximeter. Specifically, the oximeter is used to continuously detect and measure amplitudes for each blood flow pulse of the patient. Periodically, the sphygmomanometer is used to measure blood pressures (systolic and diastolic) in an artery of the patient. Immediately after the measurement cycle is completed, a computer correlates the measured systolic pressure with the pulse amplitude that is detected by the oximeter. Thereafter, the pulse amplitudes that are detected by the oximeter are used as indications of variations in the systolic pressure during the extended time interval that follows.
11 Citations
15 Claims
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1. A system for continuously monitoring the blood pressure of a patient for an extended period of time which comprises:
-
a unit for measuring blood pressures in an artery of the patient during a measurement cycle, wherein the measurement cycle has a beginning and an end, and wherein a systolic pressure (psystolic) is measured at a time “
t0”
at the beginning of the measurement cycle and a diastolic pressure (pdiastolic) is measured at the end of the measurement cycle;a device for detecting blood pressure pulses in the cardio-vasculature of a patient during the measurement cycle, wherein a first pulse near the beginning of the measurement cycle has an amplitude value “
V1”
, and a second pulse with an amplitude value “
V2”
is detected at the end of the measurement cycle wherein V1 is detected by the detecting device and a first pressure p1 is measured by the measuring unit at a determined time (“
t1”
) in the measurement cycle, and wherein an initial pressure drop Δ
1 is established at the time t1, with Δ
1 being a correction factor equal to the difference between psystolic and p1 (Δ
1=psystolic−
p1); anda computer for correlating the systolic pressure (psystolic) with “
V2+Δ
1”
, to establish a correlation therebetween, and for thereafter using the correlation to identify variations in pulse amplitudes V2 detected by the detecting device as indications of corresponding variations in systolic pressures (psystolic) during the extended period of time following the measurement cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for continuously monitoring the blood pressure of a patient for an extended period of time which comprises the steps of:
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measuring blood pressures in an artery of the patient with a unit during a measurement cycle, wherein a systolic pressure (psystolic) is measured at a time “
t0”
at the beginning of the measurement cycle and a diastolic pressure (pdiastolic) is measured at a time “
t2”
at the end of the measurement cycle;detecting blood pressure pulses in the cardio-vasculature of the patient with a device, wherein each pulse has a pulse amplitude; detecting a pulse amplitude value “
V1”
at a determined time “
t1”
;establishing an initial pressure drop “
Δ
1”
, from psystolic to p1, at the determined time “
t1”
using a computer;detecting a pulse amplitude value “
V2”
at the time “
t2”
; andusing the computer to compare a pulse differential “
Δ
v”
(Δ
v=V1−
V2) directly with a pressure differential “
Δ
p”
(Δ
p=p1−
pdiastolic) to correlate pulse metrics of Δ
v with pressure metrics of Δ
p and to equate psystolic with V2+Δ
1 and pdiastolic with V1 during the extended period of time. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A tangible computer program product for continuously monitoring the blood pressure of a patient for an extended period of time, wherein the computer program product comprises program sections that, when executed, cause a computer to perform the following method steps:
- measuring a systolic pressure (psystolic) at a time “
t0”
at the beginning of a measurement cycle;
detecting a pulse amplitude value “
V1” and
a pressure “
p1”
at a determined time “
t1”
;
establishing an initial pressure drop “
Δ
1”
, from psystolic to p1, at the determined time “
t1”
;
detecting a pulse amplitude value “
V2”
at a time “
t2”
at the end of the measurement cycle;
comparing a pulse differential “
Δ
v”
(Δ
v=V1−
V2) directly with a pressure differential “
Δ
p”
(Δ
p=pdiastolic) to correlate pulse metrics of Δ
v with pressure metrics of Δ
p; and
equating psystolic with V2+Δ
1 and pdiastolic with V1 during an extended period of time. - View Dependent Claims (15)
- measuring a systolic pressure (psystolic) at a time “
Specification