Apparatus and methods for non-invasively measuring a patient's arterial blood pressure

• US 20090131806A1
• Filed: 10/09/2008
• Published: 05/21/2009
• Est. Priority Date: 10/12/2007
• Status: Active Grant

• Current Assignee: Zhejiang Shanshi Biological Medical Devices Company Limited
• Original Assignee: Tensys Medical Inc. (Recorders & Medicare Systems Pvt Ltd.)
• Inventors: Katayama, Andrew S., Blessinger, Kurt, Butler, Anthony T., Finburgh, Simon E., Vidischak, Ronald J.
• Granted Patent: US 8,777,862 B2
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• 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 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/061 Determining position of a probe within the body employing means separate from the probe, e.g. sensing internal probe position employing impedance electrodes on the surface of the body A61B1/00158 takes precedence
• CPC Class Codes: A61B 5/489 Blood vessels
• CPC Class Codes: A61B 5/6841 by using templates
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

Improved apparatus and methods for non-invasively assessing one or more hemodynamic parameters associated with the circulatory system of a living organism. In one aspect, the invention comprises an apparatus adapted to automatically and accurately place and maintain a sensor (e.g., tonometric pressure sensor) with respect to the anatomy of the subject. The apparatus comprised of a sensor device removably coupled to an actuator which is used to position the sensor during measurements. Methods for positioning the alignment apparatus and sensor, and operating the apparatus, are also disclosed.

Claims

1. A sensor assembly adapted to sense a hemodynamic parameter from a living subject, comprising:

a substantially conformal frame; and

a sensor element, said sensor element coupled to said frame by an at least partly flexible support structure;

wherein said sensor element further comprises an electrical interface, and said sensor element is configured so as to form an electrical connection with a corresponding electrical interface of a host device simultaneously during mating of said sensor element to said host device.

2. The sensor assembly of claim 1, wherein said sensor element comprises a blood pressure sensor, and further comprises:

a biasing element;

a pressure transducer;

a plurality of electrical conductors disposed on at least one printed circuit board and adapted to electrically interface with said host device; and

a housing element adapted to encase at least a portion of said sensor element.

3. The sensor assembly of claim 2, wherein said housing element comprises a substantially pyramid-shaped portion, at least a portion of said electrical conductors being disposed thereon.

4. The sensor assembly of claim 1, wherein said host device comprises an actuator, and said at least partly flexible support structure comprises a plurality of at least partly arcuate linkages.

5. The sensor assembly of claim 1, wherein said mating of said sensor element to said host device is facilitated via one or more retention features on said frame and said sensor element.

6. The sensor assembly of claim 1, wherein said frame has a substantially smaller surface area on a radial side than on an ulnar side when disposed on said subject.

7. The sensor assembly of claim 1, wherein said frame further comprises a substantially compliant foam backing having at least one adhesive surface adapted to adhere to tissue of said subject.

8. The sensor assembly of claim 1, wherein said assembly comprises apparatus adapted to facilitate alignment of said sensor element above an artery of said subject without the use of an external alignment apparatus.

9. A method of measuring one or more physiologic parameters of a living subject, said method comprising:

disposing at least one sensor element on said subject;

mating said sensor element to a host device;

using said host device to automatically position said sensor element at a prescribed monitoring location, and calibrate said sensor element; and

measuring said one or more parameters of said subject using said sensor element.

10. The method of claim 9, wherein said act of positioning said sensor element further comprises automatically zeroing the sensor with respect to the placement of said sensor element on said subject.

11. The method of claim 10, wherein said automatic zeroing comprises at least one of:

checking for a quiescent state comprising a substantially steady sensor electrical output; and

retracting said sensor away from tissue of said living subject, and performing one or more sample applanation functions.

12. The method of claim 9, wherein said mating of said host device with said sensor element comprises simultaneously forming both electrical and mechanical connections.

13. The method of claim 9, further comprising:

decoupling said host device from said sensor element;

re-mating said host device and said sensor element after a period of time; and

obtaining second measurements of said one or more hemodynamic parameters of said subject without having to recalibrate said sensor element.

14. The method of claim 9, further comprising determining whether a sensor element is coupled to said host device by at least:

attempting to couple said sensor to said host device; and

evaluating whether proper mechanical and electrical coupling has been achieved by evaluating the presence of an electrical attribute associated with said sensor element.

15. The method of claim 14, wherein said attribute comprises at least one of:

determining whether electrical continuity between said sensor element and host device exists;

or

attempting to access a storage device on said sensor element using circuitry in said host device.

16. Apparatus adapted to measure at least one physiologic parameter of a living subject, comprising:

a support element, comprising a conforming element adapted to substantially conform to the anatomy of said subject; and

a sensing apparatus flexibly coupled to said support element, said sensing apparatus comprising a combined electrical and mechanical interface, said sensing apparatus adapted to be at least initially aligned into position over an artery of said living subject without utilizing any additional alignment apparatus;

wherein said combined electrical and mechanical interface comprises one or more features adapted to mate said sensing apparatus to a host device.

17. The apparatus of claim 16, wherein said combined interface of said sensing apparatus comprise at least a plurality of electrical conductors disposed on at least one printed circuit board.

18. The apparatus of claim 16, wherein said support element further comprises an alignment element adapted to assist in the alignment of said sensing apparatus over said artery.

19. The apparatus of claim 18, wherein said alignment element comprises at least one arrow, said arrow being adapted to align with at least a point associated with an artery of said subject.

20. The apparatus of claim 16, wherein said sensing apparatus is flexibly coupled to said support element via (i) a substantially resilient suspension loop encircling at least a portion of said sensing apparatus, and (ii) one or more associated suspension arms joining said loop to said support element.

21. The apparatus of claim 16, further comprising a second support element adapted to stabilize said sensing apparatus.

22. Apparatus useful for non-invasively measuring at least one hemodynamic parameter from the blood vessel of a living subject, comprising:

a sensor assembly comprising;

a biasing element;

a pressure sensor; and

a connector adapted to electrically connect to a recessed portion of a sensor assembly actuator; and

a substantially flexible frame element adapted to;

flexibly support said sensor assembly, said support further enabling said sensor assembly to be moved by an actuator substantially within said frame element;

at least partly conform to the anatomy of said subject proximate said blood vessel; and

provide an optical alignment feature to aid an operator in placing said apparatus on said subject.

23. The apparatus of claim 22, wherein said sensor assembly further comprises a multi-layered housing element, said housing element adapted to encase at least a portion of said connector.

24. The apparatus of claim 23, wherein said electrical connection between said connector and said actuator is accomplished via one or more friction fit features disposed on said housing element or said frame.

25. The apparatus of claim 22, wherein said connector comprises a plurality of electrical conductors disposed on a printed circuit board and adapted to electrically connect with electrical components of said recessed portion of said actuator.

26. The apparatus of claim 22, wherein said sensor assembly further comprises a substantially compliant contact material adapted to interface between an active surface of said transducer and tissue of said subject.

27. The apparatus of claim 22, wherein said sensor assembly is physically connected to said frame element by at least one substantially flexible serpentine arm.

28. A hemodynamic sensor apparatus, comprising:

a biasing element;

a pressure sensor;

a connector, said connector comprising;

one or more electronic data storage devices; and

a sensor electrical interface adapted to electrically connect to a corresponding electrical interface that is disposed at least partly within a recessed portion of a host device; and

a housing element adapted to enclose at least a portion of said electrical interface;

wherein said sensor electrical interface is adapted to mate with said corresponding interface simultaneously during the mechanical mating of said sensor apparatus to said host device.

29. The apparatus of claim 28, wherein said sensor electrical interface is comprised of a plurality of electrical conductors disposed on at least one printed circuit board and formed into a substantially pyramidal shape.

30. The apparatus of claim 28, wherein said mechanical mating comprises frictional coupling of one or more features disposed on said housing element with one or more corresponding features disposed on said host device.

31. The apparatus of claim 28, wherein said sensor apparatus is substantially elliptically shaped.

32. The apparatus of claim 28, wherein a sensing face of said sensor is substantially covered with a pliable material adapted to couple said sensing face the surface of the skin of a living subject.

33. A method of positioning at least one sensor with respect to the anatomy of a living subject, comprising:

providing said at least one sensor;

determining a general location for disposal of said at least one sensor;

disposing said at least one sensor at said general location using only an alignment apparatus that is coupled to said at least one sensor;

coupling said at least one sensor to an actuator; and

adjusting said general location of said at least one sensor using said actuator, said adjusting comprising implementing a position location algorithm.

34. The method of claim 33, wherein said act of determining a general location for disposal of said at least one sensor comprises manually locating an artery of said subject.

35. The method of claim 33, wherein said implementing a position location algorithm comprises at least one of:

checking for a quiescent state having a substantially steady sensor output;

or

retracting said sensor and performing one or more applanation functions.

36. A method of operating an apparatus adapted for non-invasively measuring one or more hemodynamic parameters of a living subject, said method comprising:

disposing a sensor proximate to a blood vessel of said subject, said sensor being substantially supported by a flexible coupling to a support element;

coupling an actuator to said sensor;

calibrating said sensor; and

measuring said one or more hemodynamic parameters;

wherein said coupling comprises electrically and mechanically coupling said sensor to said actuator in a single user action.

37. The method of claim 36, wherein said act of disposing comprises disposing said support element such that said sensor is generally proximate the blood vessel, and said act of calibrating comprises using a positioning algorithm to adjust the position of said sensor with respect to said blood vessel so that said measuring is substantially optimized.