JPH033491B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a device for assisting breathing, which is used for various patients suffering from respiratory failure. [Prior art] For respiratory support for patients with chronic respiratory insufficiency such as pulmonary fibrosis, emphysema, sequelae of pulmonary tuberculosis, and neuromuscular diseases,
Negative pressure ventilators that support physiological negative pressure breathing are useful. A patient with respiratory failure is placed inside the dome, and the lungs are inflated by applying negative pressure inside the dome and opening the chest area.
A negative-pressure ventilator with external chest pressure to assist breathing, known as the iron lung, was already produced by Drinker in 1927. However, since the device is large and made of iron, it is heavy and cannot be moved.
Moreover, due to its low efficiency, iron lungs were rarely used in the 1950s as positive pressure ventilators, which pump oxygen through a tube inserted into the trachea, became popular. However, in recent years, the drawbacks of positive pressure ventilators have been highlighted, particularly in patients with chronic respiratory failure. That is, because these patients are fully conscious, endotracheal intubation, which is used with positive pressure ventilators, is painful, and they are unable to take food or speak. Also,
Another drawback is that positive pressure can easily cause lung damage and respiratory tract infections. Furthermore, there were problems in which patients became so dependent on the ventilator that they could not be removed from the ventilator even after recovery, or the number of respiratory support had to be gradually reduced over a very long period of time. Therefore, in the 1980s, negative pressure respirators began to be reconsidered, and an external negative pressure respirator with a dome made of lightweight material was developed that could be worn on the body. (e.g. RESPIRATORY CARE, 27
(3), pp. 217-275 (1982); Clinical Thoracic Surgery, 4(2),
pp. 153-157 (1984); Respiration and Circulation, 34(4), 407-
Page 411 (1986) However, in both of these devices, mechanical breathing assistance is performed while the device maintains a certain breathing timing, which does not match the patient's desired breathing timing, resulting in so-called fighting. This caused discomfort to the patient. Furthermore, the patient has to make an effort to match the breathing rhythm of the device that has been set, which places a great physical and mental burden on the patient. The emergence of a ventilator that assists breathing in accordance with the breathing rhythm is eagerly awaited. In addition, for patients with neuromuscular diseases such as muscular dystrophy, whose breathing is weak and it is difficult to detect the timing of exhalation and inspiration, or for patients who have fallen into an apnea state, the device may be set in advance. In addition, mechanical respiratory support must be provided depending on the patient's breathing rhythm, and in the event of an abnormal situation in which spontaneous breathing is weakened or apnea occurs due to a sudden change in the patient's health condition, In this case, it is necessary to immediately switch to respiratory support using the breathing rhythm set in the device. Therefore, it goes without saying that the need for respiratory assistance based on the respiratory rhythm set in conventional devices is not denied. [Purpose of the Invention] The present invention detects the patient's breathing and provides physiological breathing support according to the patient's will in a negative pressure ventilator that conventionally cannot synchronize with the patient's breathing timing. For patients who are unable to do so, or where negative or positive pressure is applied quickly and it is difficult to detect the timing of expiration and inspiration, provide a negative pressure ventilator that can be driven at regular intervals by a timer. The purpose is to [Structure of the Invention] That is, the present invention comprises a dome made of a hard material, having an opening at the top for connecting to an air duct, and a fitting part made of an elastic material attached to the peripheral edge, and a dome for connecting to the air duct. A blower for supplying and exhausting the inside of the dome, an air duct for supplying and exhausting connecting the dome and the blower, a negative pressure regulator installed in the exhaust side piping system, a positive pressure regulator installed in the air supply side piping system, and the dome. Pressure sensor to detect internal pressure, exhaust valve and air supply valve to operate supply and exhaust, release valve to release negative or positive pressure by opening to the atmosphere, exhaust valve or air supply valve closed bypass valve, which sometimes bypasses air;
and a valve switching device for controlling the opening and closing of an exhaust valve, an air supply valve, a release valve, and a bypass valve, the timing of which is controlled by a timer. This allows for synchronous driving using a respiratory sensor. The dome used in the present invention has an external shape as shown as dome 1 in FIG. Since it inflates the body, it needs to be of a size and shape that at least covers the anterior thorax, and it is more preferable if it covers the abdomen and lateral chest and abdomen. The material is
There are no particular limitations on hard materials that do not deform even when negative or positive pressure is applied during use, but light metals such as aluminum alloys, thermoplastics such as hard vinyl chloride resin, methacrylic resin, polycarbonate resin, polyamide resin, etc. , phenolic resins, epoxy resins, unsaturated polyester resins, etc., thermosetting plastic laminates, reinforced plastics (FRP), or carbon fiber reinforced plastics (CFRP), which have high strength and are relatively light. is desirable. In addition, an elastic material 2 is provided around the periphery of the dome 1 to ensure close contact with the patient's body surface and prevent air leakage.
is installed. As the elastic material, it is best to use tubes made of natural rubber, synthetic rubber, or various thermoplastic elastomers such as styrene, olefin, ester, urethane, and polybutadiene. In addition, it may be filled with a highly viscous fluid such as liquid paraffin or ethylene glycol, or a foam material such as urethane sponge. In order to create negative or positive pressure inside the dome 1 of the present invention and perform artificial respiration, connect the duct 3 to the opening at the top and suck and discharge the air inside the dome with the blower 4, or use the supplied air. do. Although there are no particular restrictions on the blower 4 used in the present invention, in order to quickly create a negative pressure inside the dome 1, the blower 4 must be 0.2 to 2.0 m ³ /
A displacement of about min is required. In order to assist breathing by pulling up the thorax with negative pressure, it is necessary to lower the internal pressure of the dome 1 to a negative pressure of -10 to -50 mmHg, preferably -10 to -20 mmHg. If excessive negative pressure is applied, it will cause discomfort to the patient, so a negative pressure regulator 13 is installed in the exhaust side piping system 11, and the pressure inside the dome is measured by a pressure sensor.
to maintain the dome internal pressure within the negative pressure range above. Furthermore, the present invention not only inflates the chest by applying a negative pressure inside the dome when the patient inhales, but also, if necessary, can conversely push the chest by applying a pressure slightly higher than atmospheric pressure during expiration. Also in this case,
It is necessary to adjust the timing, time, strength, etc. of applying positive pressure, and in order to avoid excessive positive pressure, a positive pressure regulator 17 is installed in the air supply side piping system 15.
Adjust the pressure inside the dome 1. As a means for quickly applying negative and positive pressure, the blower 4 is kept rotating at all times, and the exhaust valve 12, bypass valves 14 and 16, air supply valve 18, and release valve 19 are opened and closed promptly. For example, when creating a negative pressure inside the dome 1, it is necessary to exhaust the air inside the dome 1, so the exhaust valve 12 is opened and the air supply valve 18 is closed so that the duct 3 communicates with the suction side of the blower 4. close. On the other hand, if the pressure is to be positive, the exhaust valve 12 may be closed and the air supply valve 18 may be opened. The release valve 19 is for quickly returning the yin-yang pressure in the dome to atmospheric pressure, so it is closed when the yin-yang pressure is applied. Since the blower 4 cannot fully demonstrate its ability when started, it is desirable to avoid starting and stopping the blower 4 as much as possible. Therefore, dome 1
When opening the interior to atmospheric pressure, the blower 4 is not necessary, but the bypass valve 1 is closed without stopping.
4 and 16 to allow air to flow from another location. This bypass method is also used for exhaust air during negative pressure and supply air during positive pressure. As described above, the dome internal pressure becomes a predetermined negative pressure as soon as the patient begins to inhale, maintains this negative pressure during inhalation, and then is released to atmospheric pressure at the same time as exhalation begins. When it is necessary to apply positive pressure, a predetermined positive pressure is reached after a certain period of time from the start of exhalation, and after maintaining that positive pressure for a certain period of time during exhalation, the positive pressure is released by releasing it to atmospheric pressure. One cycle ends with the start of the next inspiration. These changes in the dome internal pressure are measured over time by a pressure sensor, and are displayed in analog or digital form and outputted in analog form. Therefore, by connecting a recorder to the analog output terminal, it is also possible to view the change pattern of the dome internal pressure, and it is possible to select and confirm the breathing pattern. Hereinafter, the respirator of the present invention will be explained in detail with reference to the drawings. FIG. 1 is a diagram showing a piping system for supplying and exhausting air to and from a dome of a respirator according to an embodiment of the present invention, and FIG. 2 is a diagram showing changes in the internal pressure of the dome. First, at the start of inhalation 21, the dome internal pressure becomes negative pressure. At this time, the exhaust valve 12 is open and the bypass valve 1
4 is closed, bypass valve 16 is open, air supply valve 18 is closed,
The release valve 19 is in a closed state. When the dome internal pressure reaches a predetermined value set by the negative pressure regulator 13, the bypass circuit of the negative pressure regulator 13 is opened, and the negative pressure does not become any higher and is maintained at a constant negative pressure. Then, at the same time as the end of inspiration 22, the negative pressure is temporarily released to atmospheric pressure. At this time, the exhaust valve 12 is closed, the bypass valve 14 is open, the bypass valve 16 is open, the air supply valve 18 is closed, and the release valve 19 is open. If necessary, such as patients with emphysema,
Using the discharge pressure of the blower 4, the air supply side piping system 1
5, air is sent into the dome to apply positive pressure, and the patient's chest is pushed to provide positive pressure support. At this time, the exhaust valve 12 is closed, the bypass valve 14 is open, the bypass valve 16 is closed, the air supply valve 18 is open, and the release valve 19 is closed.
is closed. The timing of positive pressure assistance start 23 and the time from 23 to positive pressure release 24 are preferably set in advance on a timer so that they are constant times from the start of exhalation. Further, the maximum value of the dome internal pressure during positive pressure assistance is adjusted by relieving air so that it does not exceed a predetermined pressure set in the positive pressure regulator 17. In order to release the positive pressure, the exhaust valve 12 is closed and the bypass valve 1 is closed, as in the case of releasing the negative pressure at the end of intake 22.
4 is open, bypass valve 16 is open, air supply valve 18 is closed,
The release valve 19 is opened. Table 1 summarizes the opening and closing states of the valves in each of the above stages.

〔Effect of the invention〕

The ventilator of the present invention can synchronize with the breathing timing of various patients with respiratory failure and provide physiological breathing support that suits the patient's will, so instead of breathing in synchronization with the machine as in the past It is particularly suitable for long-term use, and is useful for early recovery of respiratory function in patients with acute respiratory failure. In addition, by using an exhalation and inhalation time setting system that prioritizes breathing synchronization, it is possible to repeat preset controlled breathing in the event of apnea or an abnormality in the breathing sensor. Therefore, even in the event of an emergency, ventilation can be maintained and danger can be avoided. Therefore, the present invention is an artificial respiration device that is highly safe and can be used comfortably for a long period of time, and is very useful in the medical industry. [Example] A dome is made from FRP that will become an artificial thoracic cavity by making a plaster cast and can cover the patient's lateral chest and abdomen.A rubber tube is attached to the periphery of the dome, and the tube is inflated with air. Inflated with. The duct installed at the top of the dome was connected to a device having a piping system as shown in Figure 1, and the dome was attached to the chest of a test subject (healthy person), and a height of 1.4 m ³ /
When the air inside the dome was discharged using a blower with a displacement of 50 min, the negative pressure reached -15 to -20 mmHg after about 0.7 seconds from atmospheric pressure, and at this time, almost no air leakage was observed from the periphery of the dome. I couldn't help it. Next, a temperature sensor using a thermistor is inserted into the subject's nostrils to detect temperature changes, that is, breathing, and the signal is converted into a differential waveform, and the inhalation/expiration trigger is triggered as shown in Figure 4. A valve switching device (not shown) that is automatically controlled by a signal from a temperature sensor adjusts the dome to negative pressure during inspiration and between normal and positive pressure during expiration in synchronization with the subject's breathing. could be generated freely. In addition, the intake time is set to 1.7 in advance in the valve switching device.
After setting the inhalation/expiration time information as 3 seconds and expiration time as 3 seconds, the subject temporarily stopped breathing or removed the temperature sensor.
In either case, immediately inhale for 1.7 seconds and exhale for 3 seconds.
I switched to controlled breathing for seconds. As described above, the respirator of the present invention was attached to a healthy subject, and as a result of measuring intraoral pressure, dome internal pressure, mouth-side inspiratory expiratory flow rate, mouth-side ventilation volume, transpulmonary pressure, etc., the present invention Using a ventilator has been shown to increase inspiratory and expiratory flow rates and tidal volume, and is effective in improving low O ₂ and hyperCO _2emia caused by ventilation failure such as pulmonary emphysema and sequelae of pulmonary tuberculosis. It was suggested.

[Brief explanation of the drawing]

Figure 1 is a diagram showing a piping system for supplying and exhausting air to the dome of a respirator that is an embodiment of the present invention;
The figure shows the change in dome internal pressure corresponding to breathing, Figure 3 is a respiratory waveform obtained by the thermistor temperature sensor installed in the nostril, and Figure 4 is a waveform obtained by converting the respiratory waveform in Figure 3 into a differential waveform, and FIG. 4 is a diagram showing a switching signal displayed by applying a trigger at a constant voltage level.

Claims (1)

[Scope of Claims] 1. A dome made of a hard material, having an opening at the top for connection to an air duct, and having a fit section made of an elastic material attached to the periphery; A blower for supplying and exhausting the inside of the dome, an air duct for supplying and exhausting connecting the dome and the blower, a negative pressure regulator installed in the exhaust piping system, a positive pressure regulator installed in the air supply piping system, and a A pressure sensor that detects pressure, an exhaust valve and an air supply valve to operate supply and exhaust, a release valve that releases negative or positive pressure by opening to the atmosphere, and a release valve that releases air when the exhaust valve or air supply valve closes. A ventilator comprising a bypass valve that bypasses the air, and a valve switching device that controls opening and closing of the exhaust valve, air supply valve, release valve, and bypass valve. 2. The ventilator according to claim 1, wherein the valve switching device is periodically driven by signals of exhalation time and inhalation time set in advance in a timer. 3. Claim 1, characterized in that the switching device is driven in a respiratory synchronized manner by exhalation and inspiration signals transmitted from a respiratory sensor.
Respirator as described in section.