JPS64893Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an optical fiber sensor for the purpose of more accurately measuring backscattered light in blood for medical purposes such as blood spectrum measurement in vivo.

Conventionally, for measuring blood spectral characteristics for the purpose of measuring in-vivo blood oxygen saturation and measuring cardiac output using the dye dilution method, or for measuring blood flow velocity using the laser Doppler method, it is necessary to Although it is necessary to measure the middle and backscattered light, there are many factors involved in this measurement, and it has often not been possible to obtain sufficiently reliable accuracy, and it has often been impossible to measure correctly. Among the reasons why this measurement accuracy cannot be obtained sufficiently, one of the major reasons related to the structure of the measuring instrument is that there is a flaw in the shape of the tip of the conventional optical fiber sensor that is inserted into the blood vessel of the living body. That's true. That is, in order to transmit measurement light into the body for measuring the blood flow velocity in the body and receive the reflected light, the tip of the optical fiber sensor including the light transmitting and light receiving fibers must be inserted into the body. In particular, it is necessary to insert it into a blood vessel, and FIG. 1 is a diagram showing the general principle of such an optical fiber sensor.The measurement light emitted from the light source 1 passes through the light transmission optical fiber 3 to the target object. In a typical system, the reflected light reaches a certain blood 5 and passes through a light-receiving optical fiber 7 and reaches a light-receiving device (not shown), where information regarding the blood to be measured is input and processed. . By the way, when measuring the blood backscattered light in such a measurement system, the tip of the conventional optical fiber sensor is shaped like the end of a normal rod, as shown in FIG. , 7 often hit the inner wall of the blood vessel 9, and the inner wall portion 11 of the blood vessel has an abnormal shape, and the measurement of blood backscattered light near the fiber tip 13 has many errors, making it difficult to obtain highly accurate measurement results. It had the disadvantage that it could not be used.

The present invention eliminates the drawbacks of the conventional instruments for measuring blood spectra, etc., and uses a plurality of fin-like or outwardly curved smooth linear sensors around the tip of an optical fiber sensor to be inserted into a living blood vessel. A soft elastic body is provided, and the elastic body is biased to expand in the radial direction. Therefore, when inserted into the blood vessel, the elastic body becomes flat along the side surface of the optical fiber, and when inserted into the blood vessel. After insertion, the optical fiber expands radially around the end so that the end of the optical fiber does not impinge directly on the inner wall of the blood vessel, thus allowing correct measurements of blood backscatter. It is something.

The optical fiber sensor according to the present invention will be described in detail below with reference to the embodiments shown in FIGS. 3 and 4.
FIG. 3 shows an embodiment of the optical fiber sensor according to the present invention, and FIG. This shows the case where In other words, the optical fibers 3 and 7 are
2 is a perspective explanatory view showing a fin-like elastic body 17 provided at the tip of the optical fiber, and a- is an axial end view of the optical fiber, in which the base 19 of the fin-like elastic body is slightly thicker. , As a result, the hard protective tube 2 equipped with the blood backflow prevention valve 27 as shown in a-
5, the fin-like elastic body 17 is inserted into the blood vessel of a living body.
is folded flat along the side surface of the optical fiber, but since it is given elasticity, after insertion into the blood vessel, its shape is restored to a radial shape as shown in a-, and the leading edge 23 of the optical fiber is folded into the inner wall of the blood vessel 9. It does not hit part 11 directly.

Further, as shown in the perspective explanatory view of FIG. 3b, a plurality of smooth dogleg curved elastic bodies 20 are provided radially around the tip of the optical fiber sensor and are biased in the radial direction. When inserting, b-
, as shown in the figure, the tip of the linear elastic body 20 slides through the guide hole 21 provided in the optical fibers 3 and 7.
It enters the blood vessel in a flat shape that closely follows the surface of the blood vessel. After being inserted into the blood vessel, the restoring force of the elastic body causes the fibers to return radially as shown in FIG. It will not hit directly. As a result, the measurement of blood backscattered light can now be performed with high accuracy in both cases a and b.

Based on the above, the effects of the present invention are as follows. Unlike conventional optical fiber sensors, the optical fiber has a smooth, soft, fin-like or dogleg-shaped elastic body at its tip, allowing it to be inserted smoothly into the blood vessel, and at the same time, it can be inserted radially into the blood vessel. By restoring to the original state, the tip of the optical fiber sensor does not directly hit the inner wall of the blood vessel and does not obstruct the blood flow, so the scattering situation of the measurement light sent from the light source is no longer abnormal as in the past. Things will disappear. As a result, the accuracy of measuring backscattered light in blood has become much higher than before. Therefore, by using the optical fiber sensor according to the present invention for various blood-related measurements in living organisms, it is possible to expect higher accuracy than ever before, and it can be used in blood spectrum measurement devices, blood oxygen saturation measurement devices, heart rate measurement devices, etc. It can be widely applied to output measurement devices, etc.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the general principle of an optical fiber sensor used for measuring biological blood, Fig. 2 is an explanatory diagram of the operation of the tip of a conventional optical fiber sensor, and Fig. 3 is an explanation of the optical fiber sensor according to the present invention. In the figure, FIG. 3a is an explanatory diagram when the elastic body is a fin-like elastic body,
FIG. 3b is an explanatory diagram in the case where the elastic body has a dogleg shape, and FIG. 4 is an explanatory diagram of the action of the tip of the optical fiber sensor of the present invention. In each figure, 1 is a light source, 3 and 7 are optical fibers, 5 is blood, 9 is a blood vessel, 11 is the inner wall of the blood vessel, 17 is a fin-like elastic body, 19 is the base of the fin-like elastic body, and 20 is a linear Elastic body, 21 is a guide hole, 2
3 is the most advanced optical fiber sensor, and 25 is a hard protection tube.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A light-transmitting optical fiber that guides measurement light from a light source into a blood vessel, and a light-receiving light that is attached to the light-transmitting optical fiber and that guides blood backscattered light to a light receiving device. In a medical optical fiber sensor comprising a fiber, the tip of the optical fiber is flattened along the side surface of the optical fiber when inserted into a blood vessel, and expandable in a radial direction around the end of the optical fiber after being inserted into a blood vessel. An optical fiber sensor comprising a plurality of elastic bodies. (2) The optical fiber sensor according to claim 1, wherein the elastic body comprises a plurality of fin-like elastic bodies arranged around the tip of the optical fiber sensor in the radial direction. (3) The optical fiber sensor according to claim 1, wherein the elastic body comprises a plurality of smooth curved elastic bodies arranged in the radial direction around the tip of the optical fiber sensor. (4) The optical fiber sensor according to any one of claims 1 to 3, wherein the optical fiber sensor is a sensor for a blood spectrum measuring device. (5) The optical fiber sensor according to any one of claims 1 to 3, wherein the optical fiber sensor is a sensor for a blood oxygen saturation measuring device. (6) The optical fiber sensor according to any one of claims 1 to 3, wherein the optical fiber sensor is a sensor for a cardiac output measuring device.