METHOD AND AN APPARATUS FOR DETERMINATION OF BLOOD PRESSURE

• US 20140187977A1
• Filed: 03/10/2014
• Published: 07/03/2014
• Est. Priority Date: 06/27/2005
• Status: Active Grant

• Current Assignee: Philips Healthcare Informatics Incorporated (Koninklijke Philips N.V.)
• Original Assignee: Sense Corp (CGI, Inc.)
• Inventors: Lading, Lars
• Granted Patent: US 9,161,701 B2
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/02141 Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits A61B5/02233, A61B5/0235 take precedence
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6832 using adhesives A61B5/259 takes precedence
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence

Abstract

A method and an apparatus for non-interfering blood pressure measurements, relates to an apparatus for continuously monitoring blood pressure for patients at home or at work. The apparatus includes an extra-corporal sensor for blood pressure determination with a flexible housing adapted to be attached to the body of a living being proximate to an artery, and an electronic circuit for wireless coupling to a remote transceiver in accordance with the blood pressure in the artery, the remote transceiver adapted for wireless coupling to the sensor for generation of a pressure signal in accordance with the blood pressure in the artery, and a processor connected to the remote transceiver for reception of the pressure signal and adapted to estimate systolic and diastolic pressure based on the signal.

Claims

1-18. -18. (canceled)

19. A blood pressure determination sensor comprising:

a flexible housing with a lower surface and a plurality of metal sheets comprising at least a first and a second mutually isolated metal sheets, wherein the flexible housing supports said mutually isolated metal sheets on the lower surface and comprises attaching means such that when the flexible housing is attached to a body of the patient, proximate to an artery using said attachment means, the mutually isolated metal sheets form the plates of a capacitor with at least the artery as a dielectric between the plates;

an inductor placed into the flexible housing and electrically connected to the mutually isolated metal sheets such that the capacitor, formed when the flexible housing is attached to the body, and the inductor is interconnected to form a resonant circuit, forming an electronic sensor circuit;

a transceiver comprising a circuit for determination of variations of resonant frequency of the resonant circuit; and

a computer comprising a processor arranged to record the resonant frequency of the resonant circuit of the sensor and perform calculations for determination of the blood pressure of the patient.

20. The blood pressure determination sensor of claim 19, wherein the computer is coupled to the transceiver by wire.

21. The blood pressure determination sensor of claim 19, wherein the transceiver is coupled to the sensor circuit by a capacitive coupling for generation of a pressure signal in accordance with the blood pressure in the artery, wherein the first and the second metal sheets are electrically connected to a third metal sheet and a fourth metal sheet, respectively, for forming capacitive couplings between the sensor and the transceiver.

22. The blood pressure determination sensor of claim 21, wherein the transceiver comprises a fifth metal sheet and a sixth metal sheet arranged to form a capacitive coupling to the third metal sheet and the fourth metal sheet, wherein the fifth metal sheet and the third metal sheet is arranged to form a capacitive coupling and the sixth metal sheet and the fourth metal sheet is arranged to form a capacitive coupling.

23. The blood pressure determination sensor of claim 19, wherein the transceiver is coupled to the sensor circuit by an inductive coupling for generation of a pressure signal in accordance with the blood pressure in the artery the transceiver is coupled to the sensor circuit via the inductor or via a further inductor coupled to the first and the second metal sheets.

24. The blood pressure determination sensor of claim 19, wherein the transceiver is positioned with a distance to the sensor circuit of less than 1 mm.

25. The blood pressure determination sensor of claim 19, wherein the transceiver comprises an astable oscillator.

26. The blood pressure determination sensor of claim 19, further comprising a processor connected to the transceiver for reception of the pressure signal and adapted to estimate systolic and diastolic pressure based on the signal.

27. The blood pressure determination sensor of claim 19, wherein the flexible housing is constructed such that damping of the resonant circuit varies with the diameter of the artery when the housing is attached to the body proximate to the artery.

28. A method for determining a blood pressure of a patient, the method comprises

providing a blood pressure determination sensor comprising a flexible housing with a lower surface, a plurality of metal sheets comprising at least a first and a second mutually isolated metal sheets and an inductor placed into the flexible housing and electrically connected to the mutually isolated metal sheets, wherein the inductor is interconnected to form a resonant circuit, forming an electronic sensor circuit and a computer comprising a processor arranged to record the resonant frequency of the resonant circuit of the;

wherein the flexible housing supports said mutually isolated metal sheets on the lower surface and comprises attaching means,

attaching the blood pressure determination sensor by the attaching means to an exterior of a body of the patient, proximate to an artery, in such a way that when the housing is attached to the body, said mutually isolated metal sheets form the plates of a capacitor with at least the artery as a dielectric between the plates such that the inductor are interconnected to form a resonant circuit, forming an electronic circuit, and wherein the mutually isolated metal sheets of the formed capacitor are provided in such a configuration that the field lines of said capacitor extend into the artery,

applying a power supply to said resonant circuit and determine variations of its resonant frequency and perform calculations for determination of the blood pressure of the patient.

29. The method of claim 28, wherein the attaching means is in form of a strap, the method comprises attaching the blood pressure determination sensor using the strap to the exterior of the body of the patient.

30. The method of claim 28, wherein the attaching means is in form of adhesive and the housing is a flexible foil having a lower surface with the adhesive thereon, the method comprises attaching the blood pressure determination sensor using the adhesive to the exterior of the body of the patient.

31. The method of claim 28, wherein the housing is a flexible foil having a lower surface with the adhesive thereon and the flexible foil supports said mutually isolated metal sheets on the lower surface.

32. The method of claim 28, wherein the method comprises determination of pulse, systolic and diastolic blood pressure from the signal from the transceiver.

33. The method of claim 28, wherein the dielectric of said capacitor comprises tissue through which the field lines of said capacitor extend when extending into the artery.

34. The method of claim 28, wherein variations of the blood pressure results in variations of the diameter of the artery and the method comprises determine the variations of the capacitance of the capacitor caused by the variations of the diameter of an artery, and determine the blood pressure.

35. The method of claim 28, wherein the variations of the blood pressure results in variations of the diameter of the artery and the method comprises determine the variations of the inductance of the inductor caused by the variations of the diameter of an artery, and determine the blood pressure.

36. The method of claim 28, wherein the method comprises determine a pressure signal related to the blood pressure at regular time intervals by fitting an expected blood pressure function of time to the measured values.

37. The method of claim 28, wherein the method comprises attaching said blood pressure determination sensor to a wrist of the patient.

38. The method of claim 28, wherein damping of the resonant circuit varies with the diameter of the artery, the method comprises determining variations of the damping of the resonant circuit.