Probe for use in non-invasive measurements of blood related parameters

• US 20020173709A1
• Filed: 06/26/2002
• Published: 11/21/2002
• Est. Priority Date: 03/15/2000
• Status: Active Grant

• Current Assignee: OrSense Ltd.
• Original Assignee: OrSense Ltd.
• Inventors: Fine, Ilya, Finarov, Alexander
• Granted Patent: US 6,983,178 B2
• Time in Patent Office: Days
• US Class Current: 600/335
• CPC Class Codes: A61B 5/0053 by applying pressure, e.g. compression, indentation, palpation, grasping, gauging
• CPC Class Codes: A61B 5/02241 of small dimensions, e.g. adapted to fingers
• CPC Class Codes: A61B 5/02255 the pressure being controlled by plethysmographic signals, e.g. derived from optical sensors
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/1491 Heated applicators
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6825 Hand
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

A probe device for use in non-invasive optical measurements of at least one parameter of the patient'"'"'s blood. The probe device comprises a finger holder in the form of a clip member that secures a fingertip between its clamping legs. The probe device supports a measuring unit for applying optical measurements to a measurement location on the finger and carries a pressurizing assembly operable for applying controllably variable, substantially under-systolic pressure to the finger in the vicinity of the measurement location. Several measurement sessions are performed at the measurement location with at least two different 3wavelength of incident light to detect light response of the medium and generate measured data indicative thereof, and the pressure applied to the vicinity of the measurement location is simultaneously varied during measurements. The light response of the medium corresponding to different wavelength of the incident light and different pressure values during measurements. The light response of the medium corresponding to different wavelength of the incident light and different pressure values is analyzed, and an optimal pressure value is determined, so as to utilize the corresp9onding light response of the medium for deriving therefrom the at least on blood parameter.

Claims

1. A method of non-invasive optical measurement of at least one parameter of the patient'"'"'s blood, the method comprising the steps of:

(a) applying a probe device to the patient'"'"'s blood perfused fleshy medium, wherein the probe device carries an optical measurement unit and a pressurizing assembly operable to apply controllably varying substantially under-systolic pressure to a measurement location on said medium;

(b) performing several measurement sessions to a measurement location on said medium to detect light response of the medium and generate measured data indicative thereof, and simultaneously varying the pressure applied to the vicinity of said measurement location, wherein each measurement session utilizes at least two different wavelength of incident light;

(c) analyzing the light response of the medium corresponding to different wavelengths of the incident light and different pressure values, and determining an optimal pressure value, so as to utilize the corresponding light response of the medium for deriving therefrom said at least one blood parameter.

2. The method according to claim 1, wherein said optimal pressure value is determined as the pressure value corresponding to certain optical criteria results.

3. The method according to claim 2, wherein the criteria results utilize at least one of the following parameters:

minimum of standard deviation, maximum of the amplitude of the light response, AC/DC ratio, parametric slope.

4. A probe device to be used in non-invasive optical measurements of a patient'"'"'s blood parameter, the probe device comprising a finger holder having a clip member that secures a fingertip between its clamping legs, wherein the finger holder supports a measuring unit for applying optical measurements to a measurement location on the finger, and carries a pressurizing assembly operable for applying controllably variable, substantially under-systolic pressure to the finger in the vicinity of said measurement location.

5. The probe according to claim 4, further comprising an additional pressurizing assembly operable for applying over-systolic pressure to a location on the patient'"'"'s finger upstream of said measurement location with respect to a normal blood flow direction, so as to create a state of blood flow cessation at said measurement location.

6. The probe according to claim 4, wherein said pressurizing assembly is associated with manipulating arms of the clip member, such as to controllably vary pressure of the clamping legs onto the fingertip secured therebetween.

7. The probe according to claim 4, wherein said pressurizing assembly comprises a bellow-like air cushion, which is interconnected by its opposite ends between the manipulating arms, and is coupled to a pneumatic drive selectively operable to supply controllably variable pressure.

8. The probe according to claim 4, wherein said pressurizing assembly is associated with the measurement location, and accommodated on the inner side of the clip member.

9. The probe according to claim 8, wherein said second pressurizing assembly comprises a cuff-like cushion coupled to a pneumatic drive selectively operable to supply the controllably variable pressure.

10. The probe according to claim 4, wherein said pressurizing assembly comprises a substantially flat balloon-like cushion coupled to a pneumatic drive, the balloon-like flat cushion being accommodated between the inner surface of the upper clamping leg and a substantially flexible pad contacting the patient'"'"'s finger.

11. The probe according to claim 4, wherein said additional pressurizing assembly comprises an air cushion cuff-ring wrapping said location upstream of the measurement location, and a pneumatic drive coupled to the cuff-ring so as to apply said over-systolic pressure to the upstream location.

12. The probe according to claim 11, further comprising a substantially rigid connector between the clip member and an element of the additional pressurizing assembly located at said upstream location on the finger, the connector being adapted to engage the finger along its middle phalanx and proximal intephalangeal joint, thereby preventing it from folding during the measurements.

13. The probe according to claim 12, wherein said connector allows for reciprocating movement of said element of the additional pressurizing assembly along the finger with respect to the clip member.

14. The probe according to claim 4, wherein said clip member is provided at the inner surface thereof with a flexible member for wrapping the measurement location of the finger, said flexible member being made of a thermoconductive material for heating said measurement location up to desired temperature.

15. The probe according to Claim 5, wherein said measuring unit, and the pressurizing assemblies are operated by a control system, having a processor for receiving and analyzing data coming from the measuring unit and indicative of the measured light response of the finger.

16. A pulse-oxymeter for non-invasive measurements of blood-related parameters of a patient, the pulse-oxymeter comprising the probe device of claim 4 and a control system that operates the pressurizing assembly and the measurement unit and generates data indicative of the measured parameters.

17. An optical measurement device for the non-invasive measurement of patient'"'"'s blood parameters, the device comprising:

a finger holder for attaching to the patient'"'"'s finger, wherein the finger holder is in the form of a clip member, which secures a fingertip between its clamping legs and supports a measuring unit in a manner allowing to apply optical measurements to a measurement location on the finger;

a first pressurizing assembly operable for applying over-systolic pressure to a location on the patient'"'"'s finger upstream of said measurement location with respect to a normal blood flow direction, so as to create a state of blood flow cessation at said measurements location;

a second pressurizing assembly associated with the finger holder and operable for applying desired pressure to the finger in the vicinity of said measurement location; and

a control system selectively operating the first and second pressurizing assembly, and selectively operating the measuring unit, the control system having a processor that received data indicative of measured signals coming from the measuring unit and analyzes said data.