JPH0319364Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ultrasonic flowmeter, and particularly to a cuff-type ultrasonic Doppler flowmeter that can accurately measure blood flow even if blood vessel diameters differ somewhat.

[Prior art]

In conventional cuff-type ultrasonic Doppler blood flowmeters, the diameter of the cuff that fixes blood vessels is fixed. Therefore, it is only possible to measure blood vessels with diameters that match the diameter of the cuff, and 0.5
It was necessary to prepare cuffs with different diameters of ~1 mm.

However, when selecting a cuff in, for example, bypass surgery, the cuff is selected based on the visually measured diameter of the blood vessel, and therefore a cuff with an inappropriate diameter may be mistakenly used.

[Purpose of the invention] The purpose of the invention is to provide a cuff that can be adapted to variations in blood vessel diameters measured by eye.

[Example of idea]

The present invention uses a single cuff to fix blood vessels with a diameter slightly smaller than a certain maximum diameter without applying excessive pressure. When the sensor and cuff are connected and fixed, the connecting part can be easily moved by the force of the hand, but by configuring a sliding movable part that has a frictional force to the extent that it does not move freely even if the hand is removed, a certain degree of friction can be achieved. It is designed to accommodate variations in blood vessel diameter (Fig. 1).

Instead of sliding together, a threaded part is made in a part of the sensor, a circular groove is made in the cuff part, and the sensor and cuff are connected to each other with a threaded part that rotates freely within the groove and that fits the threaded part of the sensor. The sensor and cuff can also be connected by a hand tube, and the positions of the sensor and cuff can be adjusted by rotating the joint tube (FIG. 2).

In the figure, 1 and 11 are ultrasonic transducers, 2 and 1
2 is a sensor built-in part, 3, 13 is a cuff part, 4, 14
5 is a notch portion, 5 is a sliding portion, 16 is a joint tube, 17 is a threaded portion, and 18 is a groove.

In an ultrasonic blood flow meter, if the ultrasonic beam does not pass through the central axis of the blood vessel, a large error will occur in measuring the blood flow velocity within the blood vessel. Therefore, it would be ideal if the radius of the semi-cylinder of the cuff and sensor were the same as the radius of the blood vessel, but in reality there is some deviation, and the purpose of this invention is to try to accommodate this deviation. However, if the diameter of a blood vessel is too small than that of the semi-cylindrical cylinder, it will be difficult to pass the ultrasonic beam through the central axis of the blood vessel, which is not preferable. Therefore, it is sufficient to have a minimum length of the movable adjustment portion that can accommodate the error when a certain blood vessel diameter is visually measured.

The error due to visual measurement can be considered to be ±50% when the blood vessel diameter is 0.5 to 2 mm, ±30% when it is 2 to 5 mm, and ±20% when it is 5 mm or more.

Therefore, it is necessary to cut out a part of the semicircular cylinder of the sensor and cuff, and set the length of the notch to the above ratio (20 to 50%) depending on the diameter of the semicylindrical cylinder. In this way, even if the diameter of the blood vessel is smaller than the semi-cylindrical diameter of the cuff and the sensor, it is possible to easily align the center axes manually.

[Effect of idea]

In addition, as in the present invention, cutting out a part of the cylinder so that blood vessels with a diameter smaller than that cylinder diameter can also be clamped is simply dividing the cylinder into two and clamping blood vessels with a diameter larger than the cylinder diameter. There are important differences in the following points. That is, in the latter case, the large-diameter blood vessel cannot, in principle, come into contact with the vibrator sections 1 and 11 of the sensor section, resulting in a space. Of course, blood vessels actually have elasticity, so if you push the blood vessel toward the vibrator, you can bring the blood vessel into contact with the vibrator, but in doing so, the end of the semi-cylindrical cuff may damage the blood vessel. things can happen. Also, measurements that apply some stress to blood vessels may cause errors.

On the other hand, in the case of the former (ie, the present invention), it can be used without applying such stress and without damaging the blood vessel at the end of the cuff, and the blood vessel easily contacts the vibrator portion.

As described above, the present invention allows blood flow in blood vessels with slightly different diameters to be accurately measured with a single cuff-type ultrasonic blood flow meter.

[Brief explanation of the drawing]

FIG. 1 is a side view of one embodiment of the present invention, and FIG. 2 is a side view of another embodiment of the present invention, in which 1 and 11 are ultrasonic transducers;
3 and 13 are the built-in part of the sensor, 3 and 13 are the cuff parts, 4 and 14 are the notch parts, 5 is the sliding part, 16 is the joint tube,
17 is a threaded portion, and 18 is a groove.

Claims (1)

[Claims for Utility Model Registration] (1) A transducer that emits an ultrasonic beam having a predetermined inclination angle with respect to the central axis of the blood vessel to be measured is exposed at the tip or embedded near the tip surface. In an ultrasonic blood flow meter probe that includes a fixed built-in part of an ultrasonic Doppler blood flow sensor and a cuff for fixing a blood vessel to the tip of the built-in sensor part, the tip of the built-in sensor part and the blood vessel to be measured by the cuff are The cuff and the sensor built-in part have a radius of 20% to 50% of the radius of the semicircular cylinder so that the contact surface is semicylindrical and the semicircular circumferential angle of the semicircular cylinder is less than 180°.
% is cut out, the cuff is provided facing the tip of the sensor built-in part, and the cuff is slidable beyond the length of the notch in a direction opposite to the tip of the sensor built-in part. An ultrasonic blood flow meter probe with a section. (2) The probe for an ultrasonic blood flow meter according to claim 1, wherein the connecting portion is characterized in that the sensor built-in portion and the cuff are connected by sliding together with friction. . (3) The ultrasonic blood flow meter probe according to claim 1, wherein the connecting portion includes a screw feeding mechanism provided between the sensor built-in portion and the cuff.