JPH0317500B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for increasing the functional residual capacity that has decreased due to surgery or other reasons by mechanically vibrating the chest wall. Note that the functional residual capacity is the static intrapulmonary capacity, and is an important parameter in terms of respiratory function, as if it decreases below a certain level, it becomes a problem in terms of life support.

Conventional technology Conventionally, for therapeutic purposes, the respiratory and inspiratory muscles are synchronized with the normal breathing rhythm and vibratory stimulation is applied alternately during an asthma attack to suppress the asthma attack and restore normal breathing. That is what is being attempted.
However, with such devices, even if the functional residual capacity increases somewhat during inspiration, the stimulation effect during inspiration is canceled by stimulating the expiratory muscles during the subsequent expiration, so the original functional residual capacity increases. The volume returns to a low state and has no relation to an increase in functional residual capacity.
On the other hand, the factors that affect the respiratory function of surgery are bleeding,
There are rapid changes in hemodynamics associated with fluid replacement, pain, and restriction of respiratory movements associated with local and systemic immobilization. Furthermore, as a direct effect, there are cases where surgical invasion is directly applied to the respiratory system, such as surgical invasion of the chest or diaphragm, such as in the case of surgery on the chest or upper abdominal organs, or surgical invasion, such as resection of the lung.

Surgical invasion directly into the thoracic or abdominal cavities results in restriction of diaphragm movement and affects lung volumes.
As a result, the functional residual capacity (FRC) decreases, resulting in eventual airway collapse and microatelectasis, leading to a decrease in overall lung volume and associated changes in exhalation mechanics. In addition, functional residual capacity FRC decreases with the introduction of general anesthesia and muscle relaxants. As a result, intrathoracic pressure becomes higher than atmospheric pressure in the gravity-dependent lung region, leading to narrowing and obstruction of the distal airways. 1
After open-heart surgery, the circulatory system stabilizes for a period of time, and a machine takes over the burden of breathing until the effects of anesthesia subside, thereby preventing a vicious cycle of respiratory failure.
In addition, in post-operative patients, an orotracheal intubation tube is often left in place during the surgery and used to manage artificial respiration. However, oral endotracheal intubation causes severe patient discomfort and has the disadvantage that the tube tends to bend in the pharynx. Furthermore, long-term endotracheal intubation while the patient is conscious and able to perceive pain, resulting in inability to speak, difficulty in eating, and inhibition of limb movement can cause extremely severe pain to the patient.

Another option is diaphragm pacing as an aid to respiratory weaning (weaning from the artificial breathing tube) in the acute period after surgery. This is a method of electrically stimulating the diaphragm, which drives ventilation, and is used to prevent infection and pressure disorders during long-term positive pressure ventilation, and to help patients return to society and home. However, there were safety issues, such as delays in the development of electrodes and the complexity of implanting limbs.

Problems to be Solved by the Invention During human respiratory movements, information from various receptors in the respiratory system enters the central region, and the rhythm of breathing is generated by control from the central region. It is also carried out by motor nerve reflexes from the spinal cord. In other words, various receptors in the respiratory system act as sensors to optimize breathing movements, whether consciously or unconsciously. As seen in asthma attacks, once these receptors are stimulated and excited, the rhythm of breathing is disrupted and the patient feels extremely suffocated, leading to a state of gasping for breath.

Sensitive receptors are further stimulated by these reflexes and continue to be excited. The intercostal muscles responsible for inhalation are located between the 2nd and 3rd intercostals, and the intercostal muscles responsible for exhalation are located in the 7th intercostal space.
- Located in the 9th intercostal space, the muscle spindles within both of these intercostal muscles are greatly excited. The excitement of muscle spindles is transmitted to the spinal cord via afferent nerves, and the α-motor neuron in the spinal cord transmits the excitement to the motor nerves, causing excitement. Increases the contraction of muscles with muscle spindles. In other words, the excitation of muscle spindles causes muscle contraction by reflex from the spinal cord, causing continuous muscle contraction and making breathing difficult. In other words, the cause of breathlessness is that the excitement associated with the contraction of the breathing muscles that does not match the breathing rhythm in the central nervous system is transmitted to the central nervous system, and the central reaction that detects that a reaction that does not follow the control system is occurring causes a feeling of shortness of breath at a conscious level. That's why. Muscle spindles are called vibration receptors and are excited by movements associated with muscle contraction and extension. It has been found that ventilation can be increased by utilizing this characteristic to synchronize mechanical vibration stimulation with inhalation and exhalation to specific parts of the chest wall. The response to this vibration stimulation is thought to be similar to the tonic vibration reflex (TVR) observed in the four muscles. In other words, it is thought that the afferent activity of sensory afferent fibers (Ia) increases at the site of vibrational stimulation, excites the reflex α-motor neuron of the spinal cord, and increases the muscular strength of the respiratory muscles, thereby increasing ventilation.

Means for Solving the Problems The inventor of the present invention applied this vibration stimulation to the muscle spindles of the second and third intercostal muscles, which are expiratory muscles, only during exhalation.
As a result of an experiment in which chest wall vibration (CWV) was activated, it was found that not only tidal volume (VT) but also functional residual capacity (FRC) increased. In addition, as a result of experiments, it was found that a vibration frequency of around 100Hz is suitable for the vibration stimulation. Fifth
The figure shows the tidal volume during chest wall vibration CWV using a Bewedict-Roth type (so-called Bell type) spirometer.
It shows an increase in VT and an increase in functional residual capacity FRC level. It can also be seen that the increases in tidal volume VT, functional residual capacity, and FRC level are reproducible. Note that the slope of the baseline indicates that the volume of the inner cylinder of the Bell spirometer decreases due to oxygen consumption due to rebreathing. The mechanism of increasing tidal volume VT is highly elastic; the primary terminals of muscle spindles that follow fine extensions are stimulated by chest wall vibration CWV, and this excitement increases the activity of sensory afferent fibers Ia, causing reflexes at the spinal cord level. This is thought to be due to the stimulation of the α-motor neuron, causing contraction of the inspiratory intercostal muscles. functional residual capacity
The reason for the increase in FRC is not only that the activity of the inspiratory intercostal muscles increases due to chest wall vibration CWV during the inspiratory phase, but also that the relaxation of the inspiratory muscles does not occur completely during inspiration, and the increased activity of the inspiratory muscles extends into the expiratory phase. This is thought to be due to the following. Next, excitation of the phrenic nerve due to chest wall vibration CWV is considered.

For this reason, we observed the movement of the diaphragm under X-ray fluoroscopy in six patients who were made to breathe quietly and subjected to chest wall vibration. As a result, the movement of the diaphragm during exhalation is a vibration body of 1.3
cm, it increased markedly by 2.6 cm.

This increases the activity of the diaphragm, and is thought to strongly suggest the existence of a hitherto unknown excitatory intercostal-diaphragmatic reflex from the upper intercostal muscles in humans. In addition, in the sitting and supine positions of the patients in the experiment, the increase in tidal volume VT was small in the supine position, but the increase in functional residual capacity FRC was significant.

Thus, the present invention provides a respiratory recognition device such as a respiratory flow transducer, which is determined by changes in a patient's breathing;
A flow meter for converting respiratory changes of the patient into electrical signals, an oscillator for generating vibration waves for stimulation, and a vibration wave of the oscillator that can be superimposed on the electrical signal for excitation and converted into a mechanical vibration wave. The present invention provides a functional residual capacity increasing device, comprising: a vibrator for increasing the amount of residual capacity, and the vibration of the vibrator is applied to both sides of the sternum between the second and third intercostals of the patient during inspiration. be.

Effects Conventionally, after upper abdominal surgery, etc., a significant decrease in vital capacity and a decrease in functional residual capacity (FRC) occur due to decreased diaphragm function and other causes, and this is the cause of pulmonary complications such as atelectasis and pneumonia. Since it was possible to increase the tidal volume VT functional residual capacity RFC using the device according to this invention, it was believed that
Post-operative pulmonary complications can be reduced.

Embodiment FIG. 1 is a block diagram of an embodiment of the present invention. In the figure, numeral 1 is a respiratory flow rate transducer that measures changes in a patient's breathing and is attached to the patient's face. In this case, since it is sufficient to recognize the patient's breathing, it is also possible to attach an ultra-small sursistor to the patient's nasal cavity and mouth to determine changes in breathing. Various other recognition devices are used, such as determining changes in the electrical impedance of the patient's chest wall and movement of the patient's abdomen due to respiration. Next, a flowmeter 2 converts the respiratory flow rate of the respiratory flow rate transducer 1 into an electrical signal, and within this flowmeter 2 changes in inhalation and exhalation are converted into square waves of different polarities.

It is not necessary to specify the polarity of exhalation and inhalation, but in the embodiment of this invention, exhalation is + and inhalation is -.
The polarity is set to , and the exciter is made to vibrate when the air is inhaled. Further, 3 is an oscillator for generating vibration waves for stimulation, which superimposes an electrical signal of the respiratory flow rate on the oscillation output of the oscillator 3 and supplies it to the exciter 4. The exciter 4 uses a small motor. It is excited by a vibration wave from the exciter 3, and converted into a mechanical vibration wave of around 100Hz by an electrical signal caused by the respiratory flow rate.
FIG.
This is a front view of the device attached to both sides of the sternum in the third intercostal space, and 6 is a band for attaching the vibrator 4 to the patient 5, but instead of the band 6, the vibrator 4 is attached with adhesive. It can also be attached to the patient's 5 skin. FIG. 3 shows the vibrator 4, FIG. A is a side sectional view, and FIG. B is a perspective view. In the figure, 7 is a vibrator attached to the shaft of the small motor 8, 9 is a case, and 10 is a cord for transmitting the excitation wave signal emitted from the oscillator 3 to the small motor 8.

In this way, the transducer 1 confirms changes in breathing, especially intake, and sends it to the flowmeter 2 as an electrical signal.
It is superimposed on the vibration wave that is applied to the oscillator 3 to excite the small motor 8, and is applied to the exciter 4 to vibrate the vibrator 7, which is applied as chest wall vibration to both sides of the sternum between the second and third intercostals of the patient 5. It is possible to increase not only tidal volume (VT) but also functional residual capacity FRC. FIG. 4 is a timing chart for driving the vibrator 4, and A is a diagram showing changes in respiratory flow rate of the patient 5.
B is an output diagram of the flowmeter 2, and C is a diagram showing the operating state of the vibrator 4. Exhalation is + polarity, inspiration is -
It is polar, thus allowing vibration stimulation to be applied to the second and third intercostals on both sides of the sternum during patient inspiration.

In this invention, mechanical vibration stimulation was applied, but a method using electrical stimulation to afferent nerves connected to muscle spindles may also be considered. Although a vibrator with a vibrator attached to a small motor was used, any other device that generates vibrations of around 100 Hz can be used as appropriate. Breath-coupled chest wall vibration has been shown to increase ventilation in normal subjects and in patients with quadriplegia. This is thought to be a tonic vibration reflex (TVR) that sends its afferent routes to muscle spindles.

The inventor has developed the following method by applying chest wall vibration to both sides of the sternum between the second and third intercostals to healthy adults only during inspiration.
Not only tidal volume (VT) but also functional residual capacity (FRC) could be increased during vibration stimulation. The increase in functional residual capacity FRC is thought to be due to the increase in inspiratory muscle activity caused by chest wall vibration extending not only to the inspiration phase but also to the expiration phase. Increases in tidal volume VT and functional residual capacity FRC using this method can be used as incentive spir-ometry under conditions such as upper abdominal surgery.

Effects of the invention Conventionally, functional residual capacity FRC was used in respiratory management.
Positive end-expiratory pressure (Positive
End Expiratory Pvessure (PEEP) and Continuous Positive Airway
Pressuve (CPAP) has been performed, but this invention has made it possible to clinically apply chest wall vibration CWV as a simpler method and device with less burden on the patient.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the configuration of an embodiment of the device according to the present invention, Fig. 2 is a front view of the vibrator 4 attached to the patient's chest wall, Fig. 3 is a structural diagram of the vibrator, and A is a side sectional view. , B is a perspective view, FIG. 4 is a timing chart of the vibration exciter drive, and FIG. 5 is a diagram showing the increase in VT and FRC level during chest wall vibration using a so-called Bell spirometer. In the figure, 1 is a respiratory flow transducer, 2 is a flow meter, 3 is an oscillator, 4 is an exciter, 5 is a patient, 6 is a band, 7 is a vibrator, 8 is a small motor, 9 is a case, and 10 is a cord .

Claims (1)

[Claims] 1. A breathing recognition device such as a respiratory flow rate transducer that detects changes in a patient's breathing, a flowmeter that converts the patient's breathing changes into electrical signals, and a vibration wave for stimulation that is converted into a mechanical vibration wave. and a vibration wave of the oscillator that can be superimposed on the electric signal for excitation, converting it into a mechanical vibration wave, and applying it as chest wall vibration to both sides of the patient's second and third sternum during inspiration. A device for increasing functional residual capacity by chest wall vibration, characterized in that it is equipped with a vibration exciter made of