DE10312272A1 - Test device for determining cerebral auto-regulative capacity of higher mammals, has one closure element which opens and closes in antiphase with other closure element - Google Patents

Abstract

When actuated, a first closure element closes and actuates a second closure element, which opens. The two closure elements thus operate in antiphase. The first closure element is biased against closing, while the second is biased against opening, so that when an actuator (5) is at rest, the first element is open, and the second closed. An independent claim is included for measuring method for non-invasive measurement of blood circulation in the brain.

Description

The invention relates to a device and a measuring method for use in veterinary medicine. These can be used for Describe or test the cerebral autoregulation of higher mammals can be used. In principle, such a device can completely or completely partially occluded.

The patent DE 4123969C2 describes a device for influencing a fluid pressure prevailing in a flowed through elastic line. The device shown there has an elastic hose placed tightly in a loop around the line, wherein the hose can be acted upon by a pressure medium source, preferably compressed air, from a pressure medium source via an inlet valve and thereby constricts the line. This device is primarily used to modulate the perfusion pressure in elastic tubes or arteries.

The EP 0417171B1 describes a device for measuring body pressures or physiological pressures, including blood pressure, intracranial pressure, intrapleural pressure, and pressure in the gastrointestinal system. It proposes an apparatus comprising a hollow, flexible tube having a first end for placement at a location where the physiological pressure is to be measured and a second end in communication with the pressure transducer device, and a liquid which fills the hose and forms a connection with the pressure transducer device.

All the above writings point several disadvantages. Switching between two "open" and "closed" states is not sufficient quickly to grasp the mechanisms of cerebral autoregulation. Moreover is the asymmetry between active closure and passive relaxation to be described as disadvantageous. It also makes a modulation Organ perfusion has limited sense since the brain is four Neck arteries are supplied at the same time. Since one artery is enough to supply the brain with sufficient blood, one would Clip modulation of the neck vessels is not useful Conclusions about a arbitrary Give modulation of cerebral blood flow.

OBJECT OF THE INVENTION

The object of the invention is therefore a cheaper one To create device, which eliminates the disadvantages of the above slow closing and opening and switching between these two operating states is reduced become.

• – eine Rechnereinheit (1) mit oder ohne Speichereinheit;
• – eine käuflich zu erwerbende Software zur Ansteuerung eines Ansteuerungsventils (11);
• – eine Antriebsquelle (2) zum Antrieb des Betätigungsmittels (5);
• – sowie zwei durch das Betätigungsmittel (5) betätigbare Verschlusselemente (6, 7) aufweist.

The object is achieved according to the invention by a device according to claim 1, which

• - a computer unit ( 1 ) with or without storage unit;
• - A software for controlling a control valve that can be purchased ( 11 );
• - a drive source ( 2 ) to drive the actuating means ( 5 );
• - and two by the actuating means ( 5 ) actuatable locking elements ( 6 . 7 ) having.

The device according to the invention enables non-tugging and always constant locking effect with one defined pressure. Moreover becomes less preparative-invasive with the apparatus presented here Approach allows because not the vessel must be wrapped around.

In addition, the change from Occlusion and opening only a few milliseconds in the apparatus shown here, what requirement for is the successful evaluation of cerebral autoregulation.

Another part of the present Invention has a holder, with the help of which a sufficient Access to the neck vessels and is guaranteed at the same time as the somatosensory cortex.

If you want the clip equipment together with the laser Doppler method to measure the cerebral blood flow in the rat considered that the clip and the laser doppler are almost 180 °, almost arranged in mirror image to each other, to which the rat can be introduced have to. Stereotactic holders from the prior art tension the rat prone. The head of the rat is at three points fixed: The snout of the rat is fixed by a bite ring. to further fastening are concentrically tapered rods in the right and left outer ear canal introduced. There the rat lying on his stomach in this way is the neck not accessible from the front (below). usually, the rat lies on the base plate of the stereotactic holder, so that access is also denied from this side. However, to to be able to close the neck vessels and keeping the operational access route as small as possible must the clip if possible from the front, i.e. with the rat lying on its stomach from below. In order to measure the cerebral blood flow, however, the laser Doppler must be used to be placed on the brain from above. Because both devices have a certain overall length, the problem of access can only be solved if the rat with head and body not in the prone position, but in the side position. To continue a constant laser Doppler position to keep, the holding apparatus must also be swiveled. According to the state of the art, there is usually only one rotatable head holder, which allows the rat head to be turned by up to 30 °, which is not enough, for sufficient access to the neck vessels and at the same time to the somatosensory To have cortex.

The holder presented here fulfills both Requirements. The rat can use its head in a known manner three-point fixed on a U-shaped support become. Then over one on the u-shaped carrier Assembled holding device of the laser Doppler in the desired position to be brought. After attaching the laser Doppler holder can then the rat in its longitudinal axis with head and body be turned so far that the front neck area is in an inclined position accessible becomes. A turn of 40-60 ° is sufficient to bring the clip to the neck vessels from the front. The sideways swing the laser Doppler is uncritically possible.

Around the U-shaped support with the associated laser Doppler holder in the longitudinal axis to be able to turn the rat it is attached to a holder so that the axis of rotation of the U-shaped carrier is approximately the longitudinal axis corresponds to the rat. A locking screw allows locking of the U-beam in the assumed rotational position. After locking it is the U-shaped support stable connected to the base plate.

New to the holder according to the invention is on the one hand the necessarily higher degree of the angle of rotation and on the other hand the rigid connection of laser Doppler holder with the rotatable U-shaped carrier what the adjustment processes significantly easier. The clip holder itself is not structurally connected to the stereotactic holder a high level of flexibility here to allow access. The clip holder and the clip itself are freely pivotable in all three spatial directions, so that the clip lock of the neck vessels vertical made to the direction of the neck vessel can be.

[Examples]

Embodiments are in the Drawings 1 to 2 are shown:

1 shows an advantageous embodiment of the device according to the invention.

2 shows the holder according to the invention.

1 shows the device according to the invention in details, which a connection of a pressure cylinder ( 5 ) with tweezers ( 6 ) and is part of a system. The system includes a computer ( 1 ) on which free software can be installed, a stimulation generator ( 2 ), a compressed air bottle ( 10 ), a compressed air regulator ( 9 ), a pressure cylinder ( 5 ), tweezers ( 7 ), a clip apparatus ( 6 ) and pneumatic line ( 3 . 4 ).

A computer ( 1 ) with stimulation software is used to create a 5/2 way valve ( 11 ) electrically via a stimulation generator ( 2 ) with output voltages of either 24 V or 0 V. The directional valve ( 11 ) depending on the position, pressurizes one of two outlets with compressed air from a compressed air bottle ( 10 ) and the interposition of two pressure levels (on the bottle rough reduction from 200 to 10 bar; in the course of pressure reduction by fine pressure reducers in working pressure ranges of 1–5 bar) is present at the inlet channel. The respective unpressurized leg is short-circuited to the room air so that the double-acting pressure cylinder ( 5 ) can act in the second chamber. In position 1 the piston of the cylinder presses a pair of tweezers mounted on the cylinder in such a way that it finally approaches the other fixed side. The extent of the closure can be limited by a set screw, so that the opening width of the tweezers ( 6 ) can be set. In position 2 the cylinder is actively returned so that the previously pressed tweezer leg is released. This leads to an opening movement of the tweezers ( 6 ) by an additional spring ( 12 ) is supported between the legs. About the tweezers ( 6 ) becomes a vascular clip ( 7 ) pressed together. The clip ( 7 ) lies freely in the tweezers ( 6 ), it can be prevented from falling out by presetting the tweezer width without already exerting pressure on the clip jaws. The clip opens by tweezers ( 7 ); the opening width can be adjusted by limiting the tweezers at the end. When the tweezers are opened, the clip is actively closed, which then goes into its rest position with a defined pressure of 0.25 N. For better mobility, the clip equipment is mounted on a freely swiveling arm.

As closure elements in this Invention clip and tweezers are used.

2 represents the holder of the invention.

The head holder is with an axis ( 13 ) with which the holder with the fixed head of the rat can be turned in the body axis. The laser Doppler apparatus is firmly attached to the head ring with a holder so that the discharge position remains constant when rotating. Since the front of the neck becomes free with rotation, the clip can be presented to clip the neck vessel of the side that becomes free. The locking screw ( 14 ) allows the U-shaped support to be locked in the assumed rotational position.

1

computer

2

generator (24V)

3

pneumatic line to open of the clip

4

pneumatic line to close of the clip

5

pneumatic cylinder zweihübig with power delivery

6

tweezers

7

clip

8th

bracket for tweezers and cylinder

9

Compressed air regulator (fine) for Working pressure 1–5 bar

10

Druckluftflasche with a pressure reducer (rough) to 10 bar

11

way valve

12

feather

13

axis of rotation

14

knob and locking screw

15

mounter for the Fixation of instruments on

rotating frame

16

baseplate

17

holder

Claims (9)

Device comprising a computing unit ( 1 ) with or without storage unit, a generator ( 2 ), software for controlling a control means ( 11 ), a drive source ( 10 ) to drive the actuating means ( 5 ), a compressed air regulator ( 9 ), a pressure cylinder ( 5 ) and pneumatic line ( 3 . 4 ), and two by the actuating means ( 5 ) actuatable locking elements ( 6 . 7 ) characterized in that the first closure element ( 6 ) closes when actuated and thus the second closure element ( 7 ) which opens so that the two locking elements ( 6 . 7 ) act in phase opposition to each other, the first closure element against closure and the second closure element ( 7 ) are pretensioned against opening so that when the actuating means is at rest ( 5 ) the first closure element ( 6 ) opened and thus the second closure element ( 7 ) - is closed by an impressed preload. Device according to claim 1, characterized in that the second closure element ( 7 ) is designed as a closure element with a very low mass and / or high preload, so that rapid opening or closing is ensured. Device according to claim 1 to 2, characterized in that the second closure element ( 7 ) is designed as a commercially available clip. Device according to claims 1 to 3, characterized in that the first closure element ( 6 ) tweezers with a spring ( 12 ), so that the opening travel and the stop of the clip can be adjusted. The device of claims 1 to 4, further comprising a measuring device, in particular a holder for a test animal and a laser Doppler device for measuring cerebral blood flow characterized in that the holder rotates the test animal around its own longitudinal axis guaranteed up to 60% so that the axis of rotation of the U-shaped beam is approximately the longitudinal axis of the experimental animal. Device according to claims 1 to 5, characterized in that that the clip holder and the clip itself in all three spatial directions are freely pivotable so that the clip closure of the neck vessels is vertical made to the direction of the neck vessel becomes. Device according to claim 5, characterized in that the measuring device has a locking screw that the Lock the U-shaped beam in the assumed rotational position guaranteed. Device according to claim 5 or 7, characterized in that the laser Doppler arrangement is rigid with the rotatable u-shaped support are connected. Measurement method for non-invasive measurement of cerebral blood flow in a test animal using the device after a of claims 1 to 8, the method comprising the following steps: - Hold tight the test animal by means of the holder according to the invention, - blood flow measurements using a laser Doppler arrangement, - Provide and evaluating the blood flow measurement data.