BLOOD PRESSURE MONITOR AND METHOD

• US 20150230774A1
• Filed: 05/05/2015
• Published: 08/20/2015
• Est. Priority Date: 11/08/2012
• Status: Abandoned Application

• Current Assignee: Hadeco Incorporated
• Original Assignee: Hadeco Incorporated
• Inventors: Thai, Le
• Application Number:
  US14/704,805
• Publication Number:
  US 20150230774A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2505/01 Emergency care
• CPC Class Codes: A61B 2505/03 Intensive care
• CPC Class Codes: A61B 2505/05 Surgical care
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/02208 using the Korotkoff method
• CPC Class Codes: A61B 5/02225 using the oscillometric method
• CPC Class Codes: A61B 5/0225 the pressure being controlled by electric signals, e.g. derived from Korotkoff sounds
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/4064 Evaluating the brain A61B5/031, A61B5/369, A61B5/14553 take precedence
• CPC Class Codes: A61B 5/7289 Retrospective gating, i.e. associating measured signals or images with a physiological event after the actual measurement or image acquisition, e.g. by simultaneously recording an additional physiological signal during the measurement or image acquisition
• CPC Class Codes: A61B 8/04 Measuring blood pressure
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/488 involving Doppler signals

Abstract

A method is provided for noninvasive, continuous, real-time monitoring of a patient'"'"'s arterial blood pressure using Doppler probes and a blood pressure cuff for measurement of a patient'"'"'s systolic and diastolic blood pressures at a major distal artery. A continuous Doppler blood flow velocity measurement is used to generate a waveform signal correlating to a cuff'"'"'s measurements of systolic and diastolic pressures. In addition, a method determines cerebral blood perfusion by providing at least two Doppler probes, one of which is placed at a distal artery with a blood pressure cuff and another of which is placed over the carotid artery or the middle cerebral artery. An algorithm calculates systolic and diastolic pressures at the distal artery and at the carotid artery or the middle cerebral artery as a function of the continuously measured Doppler blood flow velocities.

Claims

1. A method for noninvasive, continuous, real time monitoring of arterial blood pressure of a patient, comprising:

a) providing a blood pressure cuff and placing the cuff around a limb of the patient;

b) providing a Doppler ultrasound probe, positioning the probe over a distal artery below the cuff, and continuously measuring Doppler blood flow velocities with the probe;

c) inputting the Doppler blood flow velocities into a processor, wherein the processor generates a waveform signal of the Doppler blood flow velocities;

d) inflating the cuff and measuring diastolic blood pressure at a cuff pressure at which a sustained change in Doppler blood flow velocity occurs;

e) inflating the cuff further and measuring systolic blood pressure at a cuff pressure at which Doppler blood flow velocity is zero;

f) deflating the cuff;

g) correlating the Doppler waveform signal peak of maximum blood flow velocity to the systolic blood pressure and the Doppler waveform signal trough of end diastolic minimum velocity to the diastolic blood pressure; and

h) generating calculated systolic and diastolic pressures with an algorithm as a function of the continuously measured Doppler blood flow velocities.

2. The method of claim 1, wherein steps d) to g) are repeated at an interval of time to recalibrate the Doppler blood flow velocities to the systolic and diastolic blood pressures.

3. The method of claim 2, wherein the interval of time is about 3, 4, 5, 6, 7, 8, 9, or 10 minutes.

4. The method of claim 1, wherein the cuff pressure is measured by a sphygmomanometer.

5. The method of claim 1, wherein the cuff pressure is measured by an oscillometer.

6. The method of claim 5, further comprising measurement of mean arterial blood pressure.

7. The method of claim 1, step f) further comprising measuring systolic blood pressure at a cuff pressure at which the Doppler probe indicates an initial blood flow velocity, and measuring diastolic blood pressure at a cuff pressure at which the Doppler probe signal becomes muffled.

8. The method of claim 7, further comprising generating continuous measurements of systolic and diastolic pressures by continuously repeating steps d) to f), wherein deflating the cuff in step f) is stopped at measurement of diastolic blood pressure and followed by inflating the cuff in repeated step d).

9. The method of claim 1, wherein the Doppler probe is positioned over a major artery.

10. A method for noninvasive, continuous, real time monitoring of cranial perfusion via determining arterial blood pressure at the carotid artery of a patient, comprising:

a) providing a Doppler ultrasound probe and a blood pressure cuff and placing the cuff around a limb of the patient and the probe over a distal artery;

b) providing a second Doppler ultrasound probe, positioning the probe over a carotid artery in the neck, and continuously measuring Doppler blood flow velocities with the probes;

c) inputting the Doppler blood flow velocities into a processor, wherein the processor generates a waveform signal of the Doppler blood flow velocities;

d) measuring the vertical height difference between the cuff and the carotid artery;

e) inflating the cuff and measuring diastolic blood pressure at a cuff pressure at which a sustained change in Doppler blood flow velocity occurs;

f) inflating the cuff further and measuring systolic blood pressure at a cuff pressure at which Doppler blood flow velocity is zero;

g) deflating the cuff;

h) determining a corrected diastolic and systolic blood pressure at the carotid artery as a function of the height difference, wherein 1 centimeter of height is equal to a drop of 0.77 mmHg in pressure;

i) correlating the Doppler waveform signal peak of maximum blood flow velocity to the corrected systolic blood pressure and the Doppler waveform signal trough of end diastolic minimum velocity to the corrected diastolic blood pressure; and

j) generating calculated systolic and diastolic pressures with an algorithm as a function of the continuously measured Doppler blood flow velocities.

11. The method of claim 10 wherein the second Doppler probe is placed over the middle cerebral artery.

12. A system for noninvasive, continuous, real-time monitoring of arterial blood pressure of a patient, comprising:

a blood pressure cuff;

at least one Doppler ultrasound probe;

a processor for generating a continuous waveform signal of Doppler blood flow velocities;

a processor for correlating the waveform signal to blood pressures determined with the blood pressure cuff; and

a processor for generating by algorithm continuous, real-time systolic and diastolic blood pressures as a function of the continuous Doppler blood flow velocities.