Rapid non-invasive blood pressure measuring device

• US 6,939,305 B2
• Filed: 10/14/2003
• Issued: 09/06/2005
• Est. Priority Date: 06/26/1996
• Status: Expired due to Fees

• Current Assignee: Masimo Corporation
• Original Assignee: Masimo Corporation
• Inventors: Sher, Mark Henry, Caro, Richard G., Flaherty, Bryan Patrick
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US10/685,068
• Publication Number:
  US 20040077956A1
• Time in Patent Office: 693 Days
• Field of Search: 600500-503, 600/485, 600/490
• US Class Current: 600/485
• CPC Class Codes: A61B 5/02133 by using induced vibration of the blood vessel
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers

Abstract

A measurement device for generating an arterial volume-indicative signal includes an exciter and a detector. The exciter is adapted to receive an oscillating signal and generate a pressure wave based at least in part on the oscillating signal on the artery at a measurement site on a patient. The pressure wave includes a frequency. The detector is placed sufficiently near the measurement site to detect a volumetric signal indicative of arterial volume of the patient.

Claims

1. A measurement device for generating an arterial volume indicative signal, the measurement device comprising:

an exciter adapted to receive an oscillating signal and generate a pressure wave based at least in part on the oscillating signal on the artery at a measurement site on a patient, wherein the pressure wave comprises a frequency; and

a detector placed sufficiently near the measurement site to detect a volumetric signal indicative of arterial volume of the patient, wherein the volumetric signal comprises an amplitude, and wherein the measurement device is connected to a processor, which determines when the amplitude of the volumetric signal is greatest, thereby determining when transmural pressure is about zero.

2. The measurement device of claim 1, further comprising an oscillator adapted to generate the oscillating signal.

3. The measurement device of claim 1, wherein the measurement device is in communication with a processor.

4. The measurement device of claim 1, wherein the frequency is about 40 Hz.

5. The measurement device of claim 1, wherein the measurement device is in communication with an external pressure application device and the detector comprises a pressure transducer.

6. The measurement device of claim 1, wherein the detector comprises a plethysmograph.

7. The measurement device of claim 1, wherein the exciter comprises an audio transducer.

8. A method of determining the blood pressure of a patient from an arterial volume indicative signal, the method comprising:

inducing a high-frequency pressure wave onto an artery

detecting a signal indicative of arterial volume, wherein the signal includes a high-frequency component from the pressure wave;

filtering low-frequency components from the signal, thereby providing a filtered signal, wherein the filtered signal comprises an amplitude; and

determining when the amplitude of the filtered signal is greatest, thereby determining when transmural pressure is about zero.

9. The method of claim 8, wherein the filtering is performed digitally.

10. The method of claim 8, wherein the signal is detected with a plethysmograph.

11. The method of claim 8, further comprising changing the pressure induced onto the artery by an external pressure application device to determine systolic and diastolic blood pressure.

12. The method of claim 8, further comprising changing the pressure induced onto the artery by an external pressure application device to ensure the pressure induced is between systolic and diastolic blood pressure.

13. A measurement device for determining the blood pressure of a patient by finding a time when transmural pressure is approximately equal to zero, the measurement device comprising:

a device, which perturbs at least one of pressure and volume of an artery of a patient; and

a pressure transducer placed sufficiently near a measurement site to detect a signal indicative of an oscillation response when the device perturbs the at least one of pressure and volume, wherein the measurement device is in communication with a processor, which determines when an amplitude of the signal is greatest, thereby determining the time when transmural pressure is approximately equal to zero.

14. A measurement device for determining the blood pressure of a patient, the measurement device comprising:

an exciter, which induces a pressure oscillation along an artery; and

a detector, which senses the pressure oscillation and outputs a signal indicative of the pressure oscillation, wherein at least one of the exciter and detector are adapted to be placed between portions of an external pressure application device and a measurement site, wherein the measurement device is in communication with a processor, which determines a time when an amplitude of the signal is greatest, and determine a point where transmural pressure is about zero based at least in part upon the time.

15. The measurement device of claim 14, further comprising an oscillator.

16. A method of determining blood pressure of a patient, the method comprising:

providing a range of pressures to an artery;

providing an oscillating signal to the artery;

measuring a signal indicative of the oscillating signal and at least one pressure within the range of pressures;

filtering the signal indicative of the oscillating signal and at least one pressure within the range of pressures to produce a filtered signal, wherein the filtered signal comprises an amplitude;

determining a point of about zero transmural pressure when the amplitude of the filtered signal is at maximum; and

determining a pressure within the range in pressures based at least in part from said point of about zero transmural pressure.

17. A method of determining blood pressure of a patient, the method comprising:

detecting a signal indicative of an oscillation along an artery; and

determining a point of zero transmural pressure from an amplitude maximum of said detected signal.

18. A measurement device for generating an arterial volume indicative signal, the measurement device comprising:

an exciter adapted to receive an oscillating signal and generate a pressure wave based at least in part on the oscillating signal of the artery at a measurement site on a patient, wherein the pressure wave comprises a frequency;

a detector placed sufficiently near the measurement site to detect a volumetric signal indicative of arterial volume of the patient; and

a high pass filter, which substantially removes pulsatile components from the volumetric signal, thereby producing a filtered signal, wherein the filtered signal comprises an amplitude, and wherein the measurement device is in communication with a processor, which determines when the amplitude of the filtered signal is greatest, thereby determining when transmural pressure is about zero.

19. A measurement device for generating an arterial volume indicative signal, the measurement device comprising:

an exciter adapted to receive an oscillating signal and generate a pressure wave based at least in part on the oscillating signal on the artery at a measurement site on a patient, wherein the pressure wave comprises a frequency; and

a detector placed sufficiently near the measurement site to detect a volumetric signal indicative of arterial volume of the patient;

wherein the measurement device is in communication with a processor, which digitally filters the volumetric signal, thereby producing a filtered signal, wherein the filtered signal comprises an amplitude, and wherein the processor, determines when the amplitude of the filtered signal is greatest, thereby determining when transmural pressure is about zero.