JPH0819608A - Breath synchronized type breathing assisting device - Google Patents

Abstract

PURPOSE:To make it possible to automatically adjust the air supply pattern to each user, by increasing the air flow rate supplied to a mask means when the change of pressure in the system becomes below a first reference level, and decreasing the pressure in the system when, after a specified time, the change of pressure becomes above a second reference level. CONSTITUTION:A blower 1 and a nose mask 3 are connected with a conduit 2, on the way a leak valve 4 is installed, and to a branch pipe on the downstream side, a pressure sensor 5 is attached. An electric signal from the pressure sensor 5 is amplified by an amplifier 6, the data is held by a sample hold circuit 7, converted into a digital signal by an A/D converter 8, and inputted into an MPU 10. Measurements DELTAP/DELTAt are compared with a first reference level and a second reference level by the MPU. When the measurements DELTAP/DELTAt become below the first reference level, the leak valve 4 is closed to start supplying air to the nose mask 3. When, after a specified time, for example 0.5 minute, the measurements DELTAP/DELTAt become above the second reference level, the leak valve 4 is opened to decrease the pressure in the system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive airway-type breathing assistance device for pressurizing atmospheric air and supplying it to a nostril through a nasal mask. More specifically, as a preferable means for treating sleep apnea syndrome, during sleep, pressurized air is sent to the airway through the nostril to maintain a positive pressure in the airway to obstruct the airway. A device for preventing respiratory arrest due to

[0002]

2. Description of the Related Art A conventional non-breathing type positive airway pressure breathing assistance device (also called a CPAP device) has a high positive pressure even during exhalation, and it is difficult to expel exhalation, that is, air. was there. In addition, although a respiratory synchronism type positive airway pressure type respiratory assist device has been developed so far, the conventional one detects the signal at the time point via expiration,
Due to the method such as opening a leak valve for lowering the system internal pressure based on this, there was a delay at the time when the system internal pressure began to decrease, and the user was uncomfortable at the start of exhalation.

[0003]

DISCLOSURE OF THE INVENTION In the breath-synchronized positive airway pressure type breathing assistance device of the present invention, the leak valve is opened and closed by a trigger for opening the leak valve before the start of exhalation. This solves the problem so far that it is difficult for the user to exhale. Further, there are individual differences in the breathing pattern, and normally, the air supply pattern is manually adjusted according to the individual user, but the present invention is an improvement over the automatic adjustment. It is intended to provide a synchronized positive airway pressure type respiratory assist device.

[0004]

DISCLOSURE OF THE INVENTION The inventors of the present invention are in a positive pressure state for the purpose of solving the discomfort of the user at the start of exhalation in the conventional breathing entrainment type positive airway pressure type respiratory assist device. As a result of diligent research on the pressure fluctuation pattern during breathing in the human respiratory tract, it was found that a special pressure fluctuation pattern immediately before the transition from inspiration to expiration is shown, and this special pressure fluctuation pattern is exhaled by a microcomputer. The present invention has been achieved by adopting a method of recognizing the pattern to shift and opening the leak valve substantially before the user enters exhalation.

That is, the present invention is provided with a blowing means for compressed air for delivering compressed air having a pressure higher than the atmospheric pressure, a conduit means connected to the sending side of the blowing means, and the other end side of the conduit means. A respiratory assistance device comprising:
Pressure adjusting means provided in the middle of the conduit means for adjusting the internal pressure in the mask means, and pressure detecting means for detecting the system internal pressure upstream or downstream of the pressure adjusting means, Pressure change calculation means for obtaining ΔP / Δt from the system internal pressure obtained by the pressure detection means,
The ΔP / Δt obtained by the pressure change calculation means is a predetermined first value.
When the pressure becomes smaller than the reference value, the flow rate of air supplied to the mask means is increased by the pressure adjusting means to increase the system internal pressure, and after a predetermined time has elapsed, the pressure change calculating means obtains Δ
And a control means of the pressure adjusting means for reducing the pressure in the system when P / Δt becomes larger than a predetermined second reference value. To do.

In the breathing-type breathing assistance apparatus of the present invention, the maximum system pressure (Pmax) immediately before the system pressure starts to decrease due to the operation of the pressure adjusting means by the control means.
) And a predetermined pressure (Pe) difference (Pe-Pmax) is calculated and stored, and when the difference (Pe-Pmax) is larger than a predetermined value, the predetermined second reference value is increased. Two
Those having a reference value correction means are included.

Further, in the above-mentioned present invention, when the control means of the pressure adjusting means exceeds the predetermined pressure (Pe) in the system after the lapse of the predetermined time, ΔP / Δt of Included is a breathing entrainment type breathing assistance device which has the function of reducing the amount of air supplied to the mask means regardless of size.

Further, in the above invention, the pressure change computing means has a function of reducing the influence of noise components contained in the system pressure detection value obtained by the pressure detecting means. A synchronized breathing assistance device is included.

Hereinafter, the breathing synchronism type breathing assistance device of the present invention will be described in more detail with reference to the drawings as necessary.

Generally, a pressure fluctuation pattern in the system during human respiration when the air supply is switched from the atmospheric pressure to the positive pressure state by using a breathing assistance device is shown in FIG. That is, when the exhalation period is kept at atmospheric pressure and the inhalation period starts and a predetermined flow rate of air is supplied to the airway to switch to the positive pressure state, as shown in FIG. At the time of starting, the phenomenon that the pressure in the system suddenly drops is seen. After that, air is supplied and begins to become a positive pressure state, the intake amount decreases and the pressure in the system gradually rises, and the pressure increase rate decreases from the part on the balance between the air supply amount and the intake amount. .
Immediately before the end of inhalation and transition to exhalation, a phenomenon is observed in which the system enters a rest state and the pressure in the system rises rapidly.
In addition, after that, the case where the positive pressure state is released and the pressure in the system decreases is shown.

According to the present invention, the pressure (P) in the system is measured by the pressure detecting means, and the pressure change computing means calculates ΔP / Δt with respect to the time of the pressure (P) in the system. Accurately detecting the point of time when the internal pressure suddenly drops, and controlling the pressure adjusting means in the system such as the leak valve by the control means so that the air supply can be reliably started at the start of intake. Is. That is, when it is detected that ΔP / Δt becomes smaller than the preset first reference value, the pressure adjusting means such as closing the leak valve is controlled to control the air flow rate supplied to the mask means. Increase to ensure inspiration at prescription pressure.

Further, according to the present invention, by similarly calculating ΔP / Δt, the time point at which the pressure in the system starts to rise rapidly can be accurately detected to adjust the pressure in the system such as a leak valve. By controlling the means, the pressure in the system is lowered substantially before the expiration is started. That is, △ P
When / Δt becomes larger than a preset second reference value and the pressure in the system starts to rise rapidly, the pressure control means such as opening the leak valve is controlled to detect the pressure in the system. The pressure is lowered to facilitate exhalation.

Specific examples of the blowing means in the present invention include a blower and a fan for keeping the inside of the system at a positive pressure of, for example, 0 to 300 mmH ₂ O. Examples of the mask means include a cover means having only a small hole provided so that exhaled air can be discharged to the outside, and only a nose, which has a fixing band so that it can be closely attached to the face. As a specific example of the pressure detecting means in the system, there is a diaphragm type pressure sensor provided in a branch pipe in the middle of the conduit means from the air blowing means to the mask means. The pressure detecting means may be either upstream or downstream of the pressure adjusting means, but the downstream side is preferable. Further, as a specific example of the pressure adjusting means in the present invention, in addition to the leak valve, there is an automatic opening / closing valve means which can automatically adjust the opening degree provided in the middle of the conduit means. Specific examples of the pressure change calculation means include computer means such as a microprocessor unit (MPU). Specific examples of the control means of the pressure adjusting means include computer means such as MPU.

There are individual differences in the rapid rise of the pressure in the system at the time shown in FIG. 1, and the pressure adjusting means such as the leak valve operates before the prescribed pressure such as the prescription pressure by the doctor is reached. The pressure in the system may start to decrease without reaching the prescribed pressure. As a countermeasure against such a case, the present invention calculates and stores the difference (Pe-Pmax) between the system internal pressure (Pmax) and the predetermined pressure (Pe) immediately before the system internal pressure starts to decrease due to the operation of the pressure adjusting means. And a second reference value correcting means for further increasing the predetermined second reference value when the difference (Pe-Pmax) is larger than the predetermined value.

In some cases, due to individual differences in the rapid rise in the system pressure at the time shown in FIG. 1, the system pressure may exceed a prescribed pressure such as a prescription pressure by a doctor. is there. As a countermeasure against such a case, the present invention provides the mask means regardless of the magnitude of ΔP / Δt when the system internal pressure exceeds a predetermined pressure (Pe) after a lapse of a predetermined time from the start of intake. The control means of the pressure adjusting means has a function of reducing the flow rate of air supplied to the pressure control means.

In the present invention, in this way, it becomes possible to operate the apparatus in a state where the system pressure during the inspiratory period is as close as possible to the prescribed pressure Pe which is the prescribed pressure. The dynamic occlusion can be reliably prevented.

Further, in the present invention, the pressure detection result by the pressure detection means in the system is converted into an electric signal, but since noise is likely to be included in the signal, a filter means for reducing the influence of noise components is provided. Preferably. Specific examples of the filter means include software means and hardware filter means by computer means. As an example of the soft means, at least two pieces of previously detected data (two pieces if time delay is taken into consideration) are used.
A method of eliminating random noise by performing addition of about 0 pieces is preferable. An example of the hard filter means is a low pass filter such as an operational amplifier. In this way, the device of the present invention can reliably prevent malfunction due to noise.

[0018]

EXAMPLES The apparatus of the present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples.

As shown in FIG. 2, a pneumatic device using a blower 1 and a nasal mask 3 are connected by a conduit means 2 and a leak valve 4 is provided in the middle thereof, and a pressure sensor 5 is provided in a branch pipe on the downstream side thereof.
Attached. A humidifier 12 is provided between the pressure sensor 5 and the nose mask 3. The electric signal from the pressure sensor 5 is amplified by the amplifier 6, passed through a low-pass filter of about 100 Hz for noise removal, the sample-hold circuit 7 holds the data, and the A / D converter 8 converts it into a digital signal. The digital signal is taken in by the MPU 10, which is a computer means. The sampling time of the data was 10 msec and the pressure resolution was 250/256 mmH2O. The control means of the pressure adjusting means and the pressure change calculating means referred to in the present invention correspond to those shown at 11.

As software noise removal processing for ΔP / Δt, the data obtained by the previous measurement in the MPU, that is, 10 ms
The difference between the data before ec and the data of this time measurement is separately repeated 5 times, and the change in each difference is added, and the obtained value is adopted as the measured value of ΔP / Δt. The MPU compares the measured value ΔP / Δt with each set value which is the first reference value and the second reference value, and leaks when the measured value ΔP / Δt becomes smaller than the first reference value. When the valve 4 is closed and air is supplied to the nasal mask, the leak valve 4 is opened to decrease the system pressure when the measured value ΔP / Δt becomes larger than the second reference value after, for example, 0.5 seconds. I started to do it.

Immediately after the leak valve 4 is opened and closed, there is a large change in pressure, and in order to prevent the malfunction of the leak valve 4 due to large changes in ΔP / Δt, the leak valve 4 is opened and closed. Immediately after that, a so-called masking operation is performed in which ΔP / Δt is not detected, for example, only for about 50 msec.

In the MPU, the maximum pressure Pmax immediately after ΔP / Δt becomes larger than the second reference value is compared with the prescription pressure Pe, and when (Pe-Pmax) is larger than a predetermined value, 2 The reference value is further increased by a predetermined amount, or the system pressure P is compared with the prescribed pressure Pe, and when P exceeds Pe, the leak valve 4 is automatically opened.

[0023]

EFFECTS OF THE INVENTION According to the breathing assistance type breathing assistance device of the present invention, the pressure in the system starts to be lowered immediately before the start of exhalation, so that the user can obtain an excellent effect in practice of exhaling smoothly. To be Furthermore, in some cases, eliminating excessive or insufficient supply of air during inhalation due to individual differences of users,
An excellent effect is obtained that makes it possible to reliably supply the air corresponding to the prescribed pressure.

[Brief description of drawings]

FIG. 1 is an example of a pressure fluctuation pattern during human respiration when atmospheric pressure is switched to a positive pressure state.

FIG. 2 is a schematic illustration of a breathing-type breathing assistance device of the present invention.

Claims (4)

[Claims] 1. A blower means for compressed air for delivering compressed air higher than atmospheric pressure, a conduit means connected to a delivery side of the blower means, and a mask means provided on the other end side of the conduit means. And a pressure adjusting means provided in the middle of the conduit means for adjusting an internal pressure in the masking means, and a system in the upstream side or the downstream side of the pressure adjusting means. From the pressure detection means for detecting the pressure and the system internal pressure obtained by the pressure detection means, ΔP /
Pressure change calculating means for obtaining Δt, and air supplied to the mask means by the pressure adjusting means when ΔP / Δt obtained by the pressure change calculating means becomes smaller than a predetermined first reference value. To increase the flow rate to increase the system internal pressure, and to decrease the system internal pressure when ΔP / Δt obtained by the pressure change calculating means becomes greater than a predetermined second reference value after a predetermined time has elapsed. And a control means for controlling the pressure of the breathing tuned breathing assistance apparatus. 2. A difference (Pe-Pmax) between a maximum pressure (Pmax) in the system and a predetermined pressure (Pe) immediately before the pressure in the system starts to decrease by the operation of the pressure adjusting means by the control means.
And a second reference value correction means for increasing the predetermined second reference value when the difference (Pe-Pmax) is larger than a predetermined value. Breathing assistance device. 3. When the control means of the pressure adjusting means exceeds the predetermined pressure (Pe) in the system after the lapse of the predetermined time, the mask regardless of the magnitude of ΔP / Δt. 2. The respiratory-aided breathing assistance device according to claim 1, which has a function of reducing the flow rate of air supplied to the means. 4. The respiratory tuned type according to claim 1, wherein the pressure change calculation means has a function of reducing the influence of noise components contained in the system pressure detection value obtained by the pressure detection means. Respiratory aids.