MEASUREMENT OF SYSTOLIC PRESSURE

• US 20110282219A1
• Filed: 12/03/2009
• Published: 11/17/2011
• Est. Priority Date: 12/05/2008
• Status: Active Grant

• Current Assignee: ATYS Sarl
• Original Assignee: ATYS Sarl
• Inventors: Guibert, Benoit, Parzy, Denis
• Granted Patent: US 9,028,418 B2
• Time in Patent Office: Days
• US Class Current: 600/490
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• 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 5/02225 using the oscillometric method
• 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

Abstract

A noninvasive method for measuring systolic blood pressure P_syst, by applying and maintaining an astringent emptying pressure P1, which is above the systolic blood pressure P_syst, on a first zone of the finger located in the vicinity of the distal part of the finger, applying and maintaining an astringent occluding pressure P2, which is above the systolic blood pressure P_syst, on a second zone of the finger located upstream of the first zone, releasing the emptying pressure P1, releasing the occluding pressure P2 in a controlled manner, and, at the same time, acquiring at least the occluding pressure P2 and at least the blood volume V_s, at the level of the first zone as a function of time, and calculating the systolic blood pressure P_syst corresponding to the occluding pressure P2 at the moment of blood return in the finger, characterized by a substantially positive variation in the blood volume V_s of the finger at the level of the first zone.

Claims

1. Non-invasive method for measuring the systolic blood pressure (Psyst) of a finger (2) and in particular of a toe having a distal part (3), characterized in that it comprises the following steps:

applying and maintaining an astringent draining pressure (P1) on a first region (5) located in the vicinity of the distal part (3) of the finger/toe (2),

applying and maintaining an astringent occluding pressure (P2) greater than the systolic blood pressure (Psyst) of the finger/toe (2) on a second region of the finger/toe (2) located upstream of the first region (5),

releasing the draining pressure (P1),

controllably releasing the occluding pressure (P2) and at the same time acquiring at least the occluding pressure (P2) and at least the blood volume (Vs) of the finger/toe (2) at the first region (5) as a function of time,

calculating the systolic blood pressure (Psyst) corresponding to the occluding pressure (P2) at the time of blood return to the finger/toe (2) characterized by a substantially positive variation in the blood volume (Vs) of the finger/toe (2) at the first region (5).

2. The method for measuring blood pressure according to claim 1, characterized in that the draining pressure (P1) is greater than the systolic blood pressure (Psyst) of the finger/toe (2).

3. The method for measuring blood pressure according to claim 1, characterized in that the draining (P1) and occlusion (P2) pressures are applied and released automatically.

4. The method for measuring blood pressure according to claim 1,

characterized in that the draining pressure (P1) is applied and released manually, whilst the occluding pressure (P2) is applied and released automatically.

5. The method for measuring blood pressure according to claim 1,

characterized in that it comprises a waiting phase (F4) which lasts between 0 and 5 s and preferably of the order of 3 s, taking place after release of the draining pressure (P1).

6. The method for measuring blood pressure according to claim 1,

characterized in that the step for calculating the systolic blood pressure (Psyst) consists of:

extracting a pulsatile component (dAC) representing the pulsatile arterial flow in the finger/toe (2), from the variation in blood volume (Vs) of the finger/toe (2) at the first region (5) as a function of time,

calculating the systolic blood pressure (Psyst) by determining the occluding pressure (P2) at the time of re-onset of the pulsatile component (dAC) of the signal.

7. The method for measuring blood pressure according to claim 1,

characterized in that the step for calculating systolic blood pressure (Psyst) consists of:

extracting a non-pulsatile component (dDC) representing filling of the finger/toe (2) resulting from pulsatile arterial flow, from microcirculation and/or from non-pulsatile arterial flow, using the variation in blood volume (Vs) of the finger/toe (2) at the first region (5) as a function of time,

calculating systolic blood pressure (Psyst) by determining the occluding pressure (P2) at the time when the non-pulsatile component (dDC) varies substantially positively.

8. The method for measuring blood pressure according to claim 1,

characterized in that it consists of adjusting the time needed for release of the occluding pressure (P2) so that it takes place over a fixed number of cardiac cycles.

9. A non-invasive device (1) for measuring the systolic blood pressure (Psyst) of a finger/toe (2) having a distal part (3) characterized in that it comprises:

a first element (4) comprising a sensor (6) capable of measuring the blood volume (Vs) of a finger/toe (2) at a first region (5) located in the vicinity of the distal part (3) of the finger/toe (2), and a draining member (12) capable of applying or of transmitting a draining pressure (P1) to the first region (5) of the finger/toe (2),

a second element (7) comprising an arterial occluding member (9) capable of applying and/or maintaining an occluding pressure (P2) on a second region (8) of the finger/toe (2) located upstream of the first region (5),

and

a servo-controlled inflating and deflating device (10) controlled by control electronics (11) and ensuring the inflation and deflation of at least the arterial occluding member (9),

a pressure measurement system (16) measuring at least the pressure applied by the arterial occluding member (9),

and a processing system (17) controlled by the control electronics (11) and comprising;

an acquisition stage (18) which acquires at least the data delivered by the pressure measurement system (16) and by the sensor (6),

a processing unit (19) comprising;

a. means for determining the time when the blood volume (Vs) of the finger/toe (2) at the first region (5) varies substantially positively,

b. means for calculating systolic blood pressure (Psyst) corresponding to the occluding pressure (P2) at the time when the blood volume (Vs) in the finger/toe (2) at the first region (5) varies substantially positively.

10. The measuring device (1) according to claim 9, characterized in that the inflating and deflating device (10) also ensures the inflation and deflation of the draining member (12).

11. The measuring device (1) according to claim 9, characterized in that at least the occluding member (9) is formed of an air chamber.

12. The measuring device (1) according to claim 9 and characterized in that the processing unit (19) further comprises:

means for extracting a pulsatile component (dAC) representing the pulsatile arterial flow in the finger/toe (2) at the first region (5) as a function of time,

means for determining the time of re-onset of the pulsatile component (dAC) of the signal,

means for calculating the systolic blood pressure (Psyst) corresponding to the occluding pressure (P2) at the time of re-onset of the pulsatile component (dAC) of the signal.

13. The measuring device (1) according to claim 9 and characterized in that the processing unit (19) further comprises:

means for extracting a non-pulsatile component (dDC) representing filling of the finger/toe (2) resulting from pulsatile arterial flow, from microcirculation and/or from non-pulsatile arterial flow, as a function of time,

means for determining the time when the non-pulsatile component (dDC) varies substantially positively,

means for calculating the systolic blood pressure (Psyst) corresponding to the occluding pressure (P2) at the time when the non-pulsatile component (dDC) varies substantially positively.

14. The measuring device (1) according to claim 9, characterized in that the processing unit (19) comprises comparison means between the value of the occluding pressure (P2) and the value of the minimum systolic blood pressure (Psyst) which can be measured by the device (1), for example 10 mmHg.

15. The measuring device (1) according to claim 9, characterized in that the control electronics (11) drive:

the inflating and deflating device (10) to apply the draining pressure (P1) before application of the occluding pressure (P2),

the inflating and deflating device (10), to release the draining pressure (P1) after application of the occluding pressure (P2) and before the controlled release of the occluding pressure (P2),

the acquisition stage (18) to acquire, during the controlled release of the occluding pressure (P2), at least the data delivered by the pressure measurement system (16) and by the sensor (6),

the processing unit (19) to calculate the systolic pressure (Psyst) during the controlled release of the occluding pressure (P2) and at the time of detection of blood return into the finger/toe (2).