WO1998053740A1

WO1998053740A1 - Muscle tension monitor with preload controlling means

Info

Publication number: WO1998053740A1
Application number: PCT/CN1997/000054
Authority: WO
Inventors: Ning Kong
Original assignee: Ning Kong
Priority date: 1997-05-30
Filing date: 1997-05-30
Publication date: 1998-12-03
Also published as: AU2948197A

Abstract

A muscle tension monitor with preload controlling means comprises a hand supporting board for hand fixation, a pulsed constant current stimulator for stimulating the ulnar nerve to evoke the contraction of thumb musle, a force transducer for converting static tension and evoked contraction force in thumb muscle into electical signal, a preload controlling system for receiving said electrical signal and controlling said stimulator and preload controlling means, and preload controlling means for controlling the preload applied to the thumb. Said force transducer, stimulator, controlling system and preload controlling means are connected through a circuit to form a feedback control. With the muscle tension monitor, it is possible to control the preload to an optimum value automatically without the drawback of previous muscle tension monitor which need to adjust the preload manually and frequently.

Description

Muscle tension monitor with preload control device TECHNICAL FIELD

The invention relates to a medical device, in particular to a muscle tension monitor, and in particular to a muscle tension monitor with a front load control device.

technical background

Muscle relaxants, such as sarcophylline, pancuronium, atracurium, vecuronium, mevedone, and succinylcholine are commonly used in surgical and non-surgical (intensive care) medicines. These drugs vary greatly from one individual to another, and are often accompanied by many complications during application, especially due to the effects of disease, electrolyte disturbances and / or drug interactions all have an effect on the duration, intensity and side effects of muscle relaxants. For the smooth progress of patients and surgery, and to minimize the adverse reactions of muscle relaxants, it is necessary to monitor the degree of muscle relaxants when applying muscle relaxants.

Muscle relaxant monitor is an instrument for quantitatively monitoring the degree of muscle relaxant after applying muscle relaxant. The muscle tone monitor is currently recognized as a classic muscle relaxant monitor. It monitors the isometric contraction of the muscle (usually the hallucis longus muscle) after stimulating the nerve (usually the radial nerve). The force sensor is used to convert the induced muscle contraction force into electrical signals, and these signals are measured under the control of a computer, stored and compared with the ratio of force attenuation after applying muscle relaxants. In order to ensure continuous and accurate monitoring of induced muscle tone, there are several issues that need special attention when applying a muscle tone monitor: 1. The stimulus current must automatically maintain a constant current; 2. The hand must be kept in a relatively fixed position; 3. To ensure the stability of the measured isometric contraction force, the front load applied to the thumb must be kept stable.

The so-called isometric contraction is the force that has been applied to the muscle before it contracts against the contraction. In this state, the muscle contraction produces contraction but the muscle does not shorten. The force applied to the muscle is the front load. For muscle contraction, the preload is usually considered as the initial length of the muscle when it begins to contract. Under different initial lengths, that is, different preload states, the muscle contraction force is different. The so-called optimal frontal load and the optimal initial length determined by this means that the muscle is at a resting natural length, and the sarcomere is maintained approximately at 2.0 · 2 · 2μm. In this state, the muscle contraction force is the largest. Different people have different optimal preloads for the same muscle. Using a stable nerve stimulation current and a stable optimal preload at an appropriate depth of anesthesia, it is possible to continuously and accurately monitor changes in induced muscle tone.

Conventional muscle tone monitors have the function of constant stimulation current, but in the setting and stabilization of preload There are still problems in certain aspects, such as:

1. Regardless of the patient's gender, age, and physical condition, the preload is set empirically at 200-300 grams, rather than the optimal preload.

2- The instability of the monitoring data caused by the instability of the front load due to various reasons is the most important problem in the past use of the muscle tone monitor. When the muscle tension monitor is in use, when the current load exceeds the set value, it needs to be manually corrected frequently.

3. Because the front load needs to be adjusted manually, conventional muscle tension monitors cannot really achieve automatic monitoring.

Object of the invention

The object of the present invention is to provide a muscle tension monitor, which can overcome the problem of frequent manual adjustment of the front load.

Summary of invention

To achieve the above object, the present invention provides a muscle tension monitor with a front load control device, including:

1) A hand support for fixing a patient's hand;

2) Pulse constant current stimulator that stimulates the ulnar nerve of the patient to induce contraction of the thumb muscle of the patient;

³ ) a force sensor that converts the patient's thumb static muscle tension and induced muscle contraction force into electrical signals;

4) a control system that receives the electrical signal and controls the stimulator and the preload control device;

Its characteristics are: also includes

5) a front load control device for controlling the front load applied to the thumb of the patient;

The force sensor, the stimulator, the control system and the front load control device are connected by a circuit to form feedback control.

In the muscle tension monitor with a front load control device of the present invention, the front load control device is mainly composed of three main parts connected in sequence in a housing, a linear motion part, a transmission part, and a motor. The front end of the linear motion part protrudes from the housing and is connected to the patient through a force sensor. Under the control of the computer, the linear motion part moves forward or backward to drive the sensor to perform a linear motion, thereby achieving a change in the front load applied to the thumb.

The muscle tension monitor with a front load control device of the present invention has the following characteristics:

1 · The preload control device is an independent component of the muscle tone monitor; 2. Under the control of the feedback system, the preload control device can automatically find the most suitable preload, and then obtain the maximum induced muscle contraction tension. At this time, the preload is individualized rather than empirical.

3-Using the front load control device, the muscle tension monitor can monitor changes in muscle tension completely automatically, eliminating the need to manually adjust the front load frequently

Brief description of the drawings

In order to further understand the purpose, features, and advantages of the present invention, the following further describes with reference to the drawings: FIG. 1 is a schematic cross-sectional view and a connection schematic diagram of an embodiment of a muscle tension monitor with a preload control device according to the present invention;

2 is a schematic cross-sectional view and a connection schematic diagram of another embodiment of a muscle tension monitor having a preload control device according to the present invention;

3 is a schematic cross-sectional view and a connection schematic diagram of a third embodiment of a muscle tone monitor having a preload control device according to the present invention;

4 is a schematic structural diagram of a front load control device in the present invention;

Fig. 5 is an exploded schematic view of the front load control device in the present invention.

Description of the embodiments

As shown in the figures, the patient's hand, the force sensor, the computer, and the front load control device together form a closed feedback control system. When the muscle tension monitor works, the system can automatically find and stabilize the front load.

As shown in FIG. 1, the linear motion component of the front load control device in the muscle tone monitor of the present invention is the screw 2. The force sensor 1 is tightly fitted with the screw, and is connected to the thumb of the patient by the force sensor. The transmission component is composed of a gear 4 and a gear 5. The screw 2, the first gear 4, the second gear 5, and the motor 6 are sequentially mounted on the mounting housing 3 in this order. The inner hole of the first gear 4 is threaded, and when it rotates, the screw 2 can be driven. The computer controls the direction of rotation of the motor based on the electrical signal of the muscle tension transmitted by the force sensor. The rotating motion of the motor is transformed into a linear back and forth motion of the screw and the sensor through the transmission components (gear ⁵ and gear ⁴ ), thereby achieving the purpose of adjusting the front load. The guide groove 7 on the screw 2 and the positioning pin 8 on the housing 3 cooperate to form a linear movement guide structure, so as to ensure that when the gear 4 rotates under the drive of the motor 6, the screw 2 does not rotate in the cross-sectional direction and stably moves straight forward And back movement. The manual dial 9 is closely connected with the gear 4. When the manual dial is turned manually, the gear ⁴ rotates at the same time and drives the screw ² to move back and forth in a straight line to achieve the purpose of manually adjusting the front load.

FIG. ² shows another embodiment of the front load control device. The motor 6 drives the internally threaded transmission The screw sleeve 10 rotates. The rotation of the screw sleeve drives the linear motion part screw 2. The guide groove on the screw and the guide pin on the housing also form a linearly moving guide structure. A limiting structure is used to prevent the screw from being stuck or detached when the screw moves. The limiting structure consists of a front limit hole 11 and a rear limit hole 12 on the screw 2 and a limit switch 13 or a limit point light source on the housing. 14 and limit photoelectric switch 13. When the front or rear limit hole of the screw moves to the position of the limit switch, the limit switch or the limit photoelectric switch will automatically turn on. The computer receives the limit signal, that is, feedback control and adjusts the rotation direction of the motor.

Figure 3 shows a third embodiment of the front load control device. The linearly moving part of the device is a rack 15. Sensor 1 is mounted on the front of the rack. The rotary motion of the motor 6 is converted into a linear motion of the rack by the transmission member gear 17. In order to prevent the rack from getting stuck or disengaged when the rack is moving, the device is also equipped with a limit structure, which is composed of a front limit hole 11 and a rear limit hole 12 on the rack 15 and a limit switch 13 on the housing. Or the limit point light source 14 and the limit photoelectric switch 13 are composed.

In the front load control device, the motor 6 can be a DC motor or a stepper motor. If a DC motor is used, a reduction mechanism can be installed between the motor and the transmission.

The following is the main working process of this muscle tone monitor:

1. Place the patient's hand 2 ² on the hand rest 20. Place the index finger side of the patient's tiger's mouth against the positioning block 21. The role of the positioning block: 1) The patient's hand can be conveniently and quickly placed at a determined position on the hand support, so that the front load control device and sensor can also be installed quickly and accurately; 2) The hand is not easy to move, making the front load more stable.

² · The force sensor 1 installed at the front end of the linear motion part of the front load control device 29 is connected to the thumb 24 of the patient through the pull ring 23. The height and direction of the front load control device and sensors can be adjusted arbitrarily through the knobs 25 and 26. In this way, the patient's hand, the force sensor, the preload control device, the amplifier in the instrument 28, and the computer together form a feedback control system for automatically adjusting the preload.

3. The force sensor detects the tension of the thumb muscles before giving nerve stimulation. This tension is called preload. The front load was initially set to 200 grams.

4. The wrist ulnar nerve gives a 1Hz pulse with a pulse width of 0.3 or 0.2mS through a surface electrode or a needle electrode to stimulate the thumb to contract the thumb. The force sensor converts the thumb-induced contractile force into electrical signals, and these signals are stored, analyzed, and compared by a computer in the instrument ²⁸ . When the resistance between the two electrodes exceeds 5k Ω, the instrument alarms and keeps the stimulus current constant.

5 · The stimulation current starts from 10mA, each pulse increases by 5mA, and the instrument detects the induced muscle contraction tension under a 200g preload. When the maximum muscle contraction is detected, the stimulus current at this time is recorded, Based on this, the stimulus current is increased by 20%. This current is a super-strong stimulus current, and this current value is used in the subsequent monitoring process.

6. After determining the super strong stimulation current, continue to maintain the stimulation frequency of 1 Hz and measure the induced muscle tone. The gap between each muscle contraction is increased or decreased by the preload control device by 10g under the control of the computer. The front load control device controls the forward or backward movement of the screw or rack and the force sensor mounted on the front end by a motor, thereby changing the front load applied to the thumb. When the preload changes, the thumb-induced muscle contraction force increases or decreases. When the contraction force reaches the maximum, the preload value is the optimal preload.

7. In the case of super-stimulation and optimal preload and without using any drugs that affect muscle strength, the muscles have the greatest muscle contractility induced by the stimulation current. The strongest contractile force is calibrated, and the induced muscle contractile forces obtained in subsequent tests are compared with this calibration value to determine the degree of muscle loosening.

8. During the monitoring process, the instrument detects the preload every 0.5 to 5 seconds. When the detected value exceeds the predetermined range, the front load control system automatically corrects it through the feedback control system to ensure that the front load is within the determined range.

9. At any time, turn the manual dial 9 of the front load control device to manually adjust the front load as required.

The force sensor converts the patient's adductor hallucis muscle tension into an electrical signal. The computer controls the rotation direction of the motor according to the electric signal of the force, and then controls the movement direction of the transmission part and the linear motion part, and converts the rotation of the motor into the linear motion of the linear motion part and the sensor. The front load will change as the linearly moving part moves. If the front load is greater than the calibrated value, the computer controls the linear motion component to move forward to reduce the front load; otherwise, if the front load is less than the calibrated value, the computer controls the linear motion component to retreat to increase the front load. In this way, the control of the front load and the monitoring of muscle tone can be performed completely automatically.

Claims

O 98/53740

Request for Rights

1. A muscle tone monitor with a front load control device, comprising:

1) A hand support for fixing a patient's hand;

It is characterized by: also including

2. The muscle tension monitor with a front load control device according to claim 1, characterized in that it comprises a mounting housing (3), a linear motion component, a transmission component, and a DC motor or a stepper motor (6) sequentially installed on Within.

3. The muscle tension monitor with a front load control device according to claim 2, characterized in that the operation linear motion part comprises a screw (2), the front end of which is extended from the mounting housing and is connected with the force sensor (1 )connection.

4. The muscle tension monitor with a front load control device according to claim 2, wherein the transmission component comprises a first transmission gear ( ⁴ ) and a second transmission gear (5), a first transmission gear center There is a thread in the hole, and its rotation can drive the screw (2) back and forth; a second gear is installed between the first gear and the motor.

5. The muscle tension monitor with a front load control device according to claim 2, wherein the transmission component comprises a threaded sleeve (10), the sleeve is internally threaded and connected to the motor, and its rotation can drive The screw (2) moves forward and backward.

6- The muscle tension monitor with a front load control device according to claim 2, characterized in that the linear motion component comprises a rack (15), and the front end of the rack extends out of the mounting housing and communicates with the Force sensor connection.

7. A muscle tone monitor with a preload control device according to claim ^2, wherein The transmission component includes a gear (16) installed between the rack (15) and the motor (6) to move the rack back and forth.

8. A muscle tension monitor with a front load control device according to claim 2, wherein a positioning pin (8) is provided on the mounting housing.

9. The muscle tension monitor with a front load control device according to claim 3, wherein the screw (2) is provided with a guide groove (7) and together with the positioning pin, constitutes a guide of the screw structure.

10. The muscle tension monitor with a front load control device according to claim 6, wherein the screw (3) and the rack (15) are provided with a front limit hole (11) and a rear limit Bit hole (12).

11. The muscle tension monitor with a front load control device according to claim ² , characterized in that a limit switch (13) is provided on the muscle tension monitor, and together with the front limit hole and the rear limit hole, a screw and Limiting structure for rack movement. '

Muscle tension monitor has a 12-front load control device according to claim 2, wherein the stopper is provided on its point light source G ⁴⁾ and the photoelectric control limit switch (13) and with said front limiting hole Together with the rear limit hole, a limit structure for the movement of the screw and rack is formed.

13- The muscle tension monitor with a front load control device according to claim 2, characterized in that the manual dial (9) of the transmission member is tightly connected with the first gear (4).

I ^4. The muscle tension monitor with a front load control device according to claim 1, wherein the hand rest includes a positioning block.

15. The muscle tone monitor with a preload control device according to claim 1, wherein a computer of the control system is used to analyze and store the electrical signal and control the stimulator and preload control Device.