NONINVASIVE BLOOD-PRESSURE MEASURING DEVICE

Abstract

The invention relates to a measuring device for continuously determining the intra-arterial blood pressure in a finger of a hand, the measuring device comprises a base part and a cuff part. A light source for near-infrared light and a photodetector are provided for the finger. The light sources and the photodetectors are connected to an associated optical emission surface or optical collector surface via a respective so-called light pipe for coupling emitted light into the finger tissue or decoupling non-absorbed light from the finger tissue. The cuff-side and base-part-side sections of the light pipes are connected to one another via separable optical contact points at the interface between the cuff part and the base part. On the base-part side, a cover glass closes flush with the housing of the base part and is attached to the contact points.

Claims

1. A measuring device for continuous determination of an intra-arterial blood pressure on a finger of a hand, the measuring device comprising: a base part; a cuff part that is configured to connect to, and separate from, the base part without tools; a radiation source configured for emitting light into the finger through an optical emission surface; a photodetector configured for detecting a portion of the light captured by an optical collector surface and not absorbed in the finger; a cuff, which is arranged in the cuff part and can be filled with a fluid, for receiving the finger; a pressure control system arranged at least partially in the base part for regulating a fluid pressure in the cuff as a function of the detected non-absorbed portion of the light, wherein at least one of the radiation source or the photodetector is arranged in the base part; and a respective non-fiber-optic light guide connection that is at least partially arranged in the cuff part between at least one of the radiation source arranged in the base part or the photodetector and at least one of the optical emission surface or the optical collector surface, wherein the respective non-fiber-optic light guide connection has an optical contact point that is separable from the base part together with the cuff part for at least one of coupling light from the base part into the cuff part or decoupling light from the cuff part into the base part.

2. The measuring device according to claim 1, wherein the radiation source and the photodetector are arranged in the base part, and the respective non-fiber-optic light guide connection is provided both between the radiation source arranged in the base part and the optical emission surface and between the photodetector and the optical emission surface.

3. The measuring device according to claim 2, wherein there is no electrical line connection between the base part and the cuff part.

4. The measuring device according to claim 3, wherein the cuff part has an electronic component for wireless identification of the cuff part.

5. The measuring device according to claim 2, wherein the cuff part has an electronic component for identification of the cuff part, and an interface for querying the electronic component, as a single electrical line connection between the base part and the cuff part.

6. The measuring device according to claim 2, wherein the radiation source and the photodetector are arranged on a common circuit board.

7. The measuring device according to claim 6, wherein a driver switch for at least one of the radiation source or an amplifier circuit for the photodetector is further arranged on the circuit board.

8. The measuring device according to claim 1, wherein at least one lens or a lens geometry integrated into the respective non-fiber-optic light guide connection is provided at least one of at a transition between the radiation source and the respective non-fiber-optic light guide connection or at a transition between the photodetector and the respective non-fiber-optic light guide connection.

9. The measuring device according to claim 1, wherein the optical contact point is provided with at least one lens or a lens geometry integrated into the respective non-fiber-optic light guide connection.

10. The measuring device according to claim 1, wherein the optical contact point is provided with at least one cover glass.

11. The measuring device according to claim 1, wherein at least one of the optical emission surface or the optical collector surface is equipped with a Fresnel structure.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0049] FIG. 1 shows schematically a device according to the invention with a patient's hand placed thereon in a side view.

[0050] FIG. 2 shows the same device as in FIG. 1, but without the hand and in a front view, i.e. from the left in FIG. 1.

[0051] FIG. 3 shows an enlarged view of FIG. 2 with schematically sketched photoplethysmographic components.

[0052] FIG. 4a shows the device as shown in FIG. 1 but without the hand and with marking of the sectional plane for the representation from FIG. 4b.

[0053] FIG. 4b is a sectional view of a cutout of the device as shown in sectional plane A-A′ from FIG. 4, wherein break line B-B′ of the cutout is also indicated in FIG. 3.

[0054] FIG. 5 shows the base part and cuff part separated from one another in a side view, similar to FIGS. 1 and 4a.

[0055] The blood pressure measuring device 1 is designed as a photoplethysmographic measuring system that functions according to the Vascular Unloading Technique. Measurement components, that is to say in particular electronic components 23a, 23b, 24a, 24b, and mechanical components of the pressure-generation and pressure-control system 20 can in principle be implemented similarly to the prior art mentioned at the beginning. Essential components of the exemplary embodiment described are sketched in FIG. 2 and especially FIGS. 3 and 4b, which show the blood pressure measuring device 1 shown in a side view in FIGS. 1 and 4a in the front view (from the left in FIGS. 1 and 4a) or sectional view (FIG. 4b). Elements arranged within the housing 2 of the base part or within the cuff part are indicated by dashed lines in FIG. 3.

[0056] The cuff part 8 is designed to accommodate two fingers, which makes it possible to measure alternately on both fingers. For reasons of hygiene, the cuff part 8, together with the palm rest 17, is designed as a disposable item, which is attached to the reusable base part 18 in a detachable manner by means of a plug-in connection. FIG. 5 shows the

[0057] The two inflatable finger cuffs 19a, 19b are connected to the pressure-generation and pressure-control system 20 via a distributor 21 and a connection 22 at the interface between the cuff part 8 and the base part 18. In this case, the connection 22 is preferably equipped with a valve (not shown) that closes the connection on the base-part side flush with the housing 2 of the base part 18 when the base part 18 and cuff part 8 are not connected to one another. In alternative embodiments, the finger cuffs 19a, 19b can also be connected separately to a (optionally also respective) pressure-generation and pressure-control system 20 and can thus be controlled separately.

[0058] For each of the two fingers, a light source 23a, 23b for near-infrared light, for example a light-emitting diode, and a photodetector 24a, 24b are provided, which are arranged on a common circuit board 4 which also supports the driver switches (not shown) for the light sources 23a, 23b and the amplifier circuits (not shown) for the photodetectors 24a, 24b.

[0059] The light sources 23a, 23b and the photodetectors 24a, 24b are connected to an associated optical emission surface 25a, 25b or optical collector surface 26a, 26b for coupling emitted light into the finger tissue or decoupling unabsorbed light from the finger tissue via a respective light pipe 27, i.e. a light guide not designed as a fiber bundle. The optical emission and collector surfaces 25a, 25b, 26a, 26b are equipped with a Fresnel structure for the directional coupling in and out of the measuring radiation.

[0060] The light emitted by the respective light source 23a, 23b is coupled into the respective light pipe 27 via the respective lens 3a, 3b.

[0061] The cuff-side and base-part-side sections of the light pipes 27 are connected to one another via separable optical contact points 28 at the interface between the cuff part 8 and the base part 18. On the base-part side, a cover glass 29, for example mineral glass or sapphire glass, which closes flush with the housing 2 of the base part 18 and is as scratch-resistant as possible, is attached to the contact points.

[0062] The pressure-generation and pressure-control system 20 regulates the cuff pressure in accordance with the signal received by one of the photodetectors 24a, 24b so that the portion of the near-infrared light emitted by the associated light source 23a, 23b that is not absorbed in the corresponding finger remains as constant as possible, i.e. a counterpressure which varies according to the pulsatile portion of the arterial blood pressure is generated and transferred to the respective finger via the flexible cuff membranes 9a, 9b, so that the blood volume area present in the respective finger area (and plethysmographically detected by the respective light source-detector pair 23a, 24a or 23b, 24b) remains approximately constant. The counterpressure in the cuffs 19a, 19b regulated accordingly by the pressure-generation and pressure-control system 20 is detected as a blood pressure measurement signal by a sensor in the pressure-generation and pressure-control system 20 and can be output to a patient monitor via a suitable electronic interface through the cable 12.

[0063] The device 1 is also supplied with power via the cable 12.