JPH0122647Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an apparatus for measuring intravascular pressure in an arteriovenous shunt region of an artificial dialysis patient.

Dialysis patients usually have an internal shunt surgically placed between an artery and a vein in their forearm to facilitate extracorporeal circulation of blood. As dialysis continues, this shunt expands and becomes lump-like. By touching this area from the body surface, it is possible to sense pressure related to the patient's blood pressure.

The present invention attempts to realize indirect continuous measurement of the patient's blood pressure by attaching a pressure transducer to the shunt part and continuously measuring the pressure.

The following will be explained with reference to the drawings. In FIG. 1, 1 is an artery in the arm, 2 is a vein, and 3 is an internal shunt. The veins in the internal shunt are shaped like a lump as shown in the figure, and the measuring device according to the present invention shown in FIG. 2 is attached to that part. The device includes a pressure transducer 4 using a piezoelectric element, a support plate 5 supporting the pressure transducer 4,
a fixing band 6 for fixing the support plate 5 to the arm;
It consists of several leg length adjustment screws 7 screwed into the support plate 5. This device is fixed to the arm 8 with a band 6, and the angle of the support plate 5 is adjusted by applying the lower end of the adjustment screw 7 to the skin 10, so that the pressure sensitive surface 4a of the pressure transducer 4 is connected to the corresponding blood vessel wall of the vein 2. Install it so that it forms a plane parallel to 2a.

This pressure measurement principle is an extension of the plane contact method. That is, the error between the intravascular pressure of the shunt part 3 and the pressure at the pressure sensitive surface 4a of the pressure transducer 4 on the body surface is determined by the total tension of the skin 10, subcutaneous tissue 11, and blood vessel wall 2a directly below the pressure sensitive surface and their curvatures. However, when this device is installed so that the part 2a of the blood vessel wall and the pressure-sensitive surface 4a become parallel planes by adjusting the leg length appropriately as shown in Fig. 2, the curvature of these becomes zero, the above-mentioned error becomes zero, and the intravascular pressure in the shunt region can be accurately measured. The measured value is indicated by an indicator 12 containing an amplifier.

FIG. 3 shows the relationship between the pushing distance and the indicated pressure after the pressure-sensitive surface and the skin begin to contact each other. According to this, the indicated pressure becomes constant within a considerable range of the pushing distance, and the above-mentioned parallel plane state is verified here. Utilizing this patent, it is possible to continuously measure pressure with high reliability even without strict mounting. In FIG. 3, patient A has a large bulge on the body surface of the shunt region, and patient B has a small bulge on the body surface of the shunt region.

The indicated pressure is pulsating in synchronization with the heartbeat. By measuring the average value or peak value, the patient's blood pressure can be indirectly known. For example, if the artery that supplies blood to the shunt is compressed, this measured value will drop to zero.

The most important thing to be careful about during dialysis is to prevent the patient's blood pressure from dropping in a short period of time, resulting in a so-called shock state. Currently, blood pressure is only measured intermittently every 30 to 60 minutes using a general-purpose cuff-type sphygmomanometer during 4 to 5 hours of dialysis.

However, shots occur over a short period of minutes. Therefore, by interpolating the intermittent measurement of blood pressure using this device, it is possible to detect the start of a rapid drop in blood pressure and take prompt action, thereby preventing a shock.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the arteriovenous shunt, Fig. 2 is a cross-sectional view of the device of the present invention taken along line A-A' in Fig. 1,
FIG. 3 is a diagram showing pressure indication characteristics. 1... Artery, 2... Vein, 2a... Blood vessel wall, 3
...Inner shunt section, 4...Pressure transducer, 4a...
Pressure sensitive surface, 5... Support plate, 6... Fixed band, 7...
...Leg length adjustment screw, 8...Arm, 10...Skin, 11
...subcutaneous tissue, 12...indicator.

Claims (1)

[Scope of utility model registration request] A support plate, a pressure transducer supported within the support plate and having its pressure-sensitive surface exposed on the measurement side of the support plate, a plurality of leg length adjustment screws attached to the support plate, and fixing the support plate to the measurement site. The leg length adjustment screw makes plane contact between the measurement side of the support plate, the pressure sensitive surface of the pressure transducer, and a part of the blood vessel wall at the arteriovenous shunt through the skin and subcutaneous tissue. 1. An arteriovenous shunt intravascular pressure measuring device, characterized in that it is configured to be adjustable.