JPH0119930Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a respiration monitoring device, and particularly to a respiration monitoring device that can detect and monitor abnormal conditions of respiration in an extremely safe and highly sensitive manner.

Generally, when administering anesthesia to a patient (subject), performing surgery, or monitoring a patient after surgery, it is necessary to monitor the patient's breathing status in order to quickly identify any abnormalities in the patient. be. Conventionally, two methods are known as detection methods for monitoring a patient's respiratory condition.

The first method is to attach electrodes to the patient's abdomen and detect based on changes in impedance between the electrodes due to displacement of the abdomen due to breathing. However, this detection method has the problem of being dangerous because it requires the electrode to be directly attached to the human body. Particularly when used on severely debilitated patients or newborn infants, they tend to be sensitive to minute currents used to detect impedance, and are likely to have adverse effects. Additionally, there is a risk of electric shock if an overcurrent flows due to equipment failure.

The second method, as disclosed in Japanese Patent Application Laid-Open No. 51-52695, is a method of detecting the respiratory state based on temperature changes. In this method, a temperature sensor is provided in a mask, the mask is applied to the patient's throat, and the change in exhaust temperature when the patient breathes is detected. However,
This method has the problem that it cannot be used in conjunction with a person wearing an anesthesia mask, and that detection errors are likely to occur when there is a large difference between the ambient temperature and the temperature caused by the exhaust air depending on the season. Furthermore, with masks that use temperature sensors, the mask that houses the temperature sensor is made for adults, so it may not be possible to use it on newborns, or even if it is used, the mask may shift when the newborn moves its head. There was a problem with this, which could cause suffocation. Furthermore, electrodes for temperature detection may come into contact with the human body.

By the way, when monitoring a patient's breathing condition, there is not only a need to monitor the breathing condition moment by moment, but also a desire to detect whether or not the patient is breathing at a certain period.

Therefore, the purpose of this device is that it can be used even by people with weak physical strength such as newborns, that it can monitor the respiratory status extremely safely, that it can be used in combination even with an anesthesia mask, and that it can be used in conjunction with an anesthesia mask that does not affect the ambient temperature. It is an object of the present invention to provide a respiration monitoring device which can detect the respiratory state with high precision without being affected, and can monitor the presence or absence of a respiration state in a certain period.

In summary, this idea extracts the minute pressure caused by breathing from the patient's nose and mouth and applies it to the minute pressure sensor, and when the detection output of the minute pressure sensor does not exceed a set period, it detects an abnormal condition. The notification is made based on the detection of the state.

Hereinafter, specific embodiments of this invention will be described with reference to the drawings.

FIG. 1 is an illustrative view showing the external appearance of a respiratory monitoring device 10 according to an embodiment of the invention and its usage condition. In the figure, a breathing monitor device 10 has a power switch 12, light emitting diodes (or lamps) 13 and 14, a selection switch 15, a volume control knob 16, and a nozzle 17 formed on a front panel 11 of the main body. The power switch 12 turns the power on or off. The light emitting diode 13 emits light every time it detects one breathing state to indicate that the breathing state is normal. The light emitting diode 14 is an example of a notification means, and displays in a visually recognizable manner that the breathing condition is abnormal. The selection switch 15 selects, for example, a mode in which the light emitting diode 13 is displayed or an intermittent beep indicating a normal breathing state is generated when one breath is detected in the OFF position, and the selection switch 15 selects a mode in which the light emitting diode 13 is displayed or an intermittent tone indicating a normal breathing state is generated when one breath is detected in the OFF position, and the selection switch 15 is in the OFF position. (15, 30, 60 in the illustration) to select a mode that detects abnormal breathing when no breath is taken during a predetermined unit time (for example, 15 seconds, 30 seconds, 60 seconds). be. Therefore, the selection switch 15 is used as a period setting means.

A tube 18 such as a rubber tube is connected to the nozzle 17. The distal end of tube 18 is inserted into the nose or mouth of the patient whose respiratory status is to be monitored, or into an anesthetic mask. The tube 18 is relatively thin, but preferably the nozzle 17
It is used in conjunction with a tube that is thinner than the tube that is inserted into the patient's nose or mouth.

FIG. 2 is an illustrative diagram of an example of a micro-pressure sensor built into a respiration monitoring device. In particular, FIG. 2 a shows a micro-pressure sensor 21 using a switch as a detection means, and FIG. 2 b shows a photoelectric sensor. Low pressure sensor 2 used
2 is shown.

First, the configuration of the micro-pressure sensor 21 will be described with reference to FIG. 2a. The low pressure sensor 21 includes a housing 211. Nozzles 212 and 212' are formed on both sides of the housing 211 to allow gas to enter and exit the housing. Inside the housing 211, a diaphragm 213 and a movable contact 215 are provided facing each other with a certain distance therebetween, and a fixed contact 214 is provided opposite the movable contact 215. In addition, diaphragm 2
13 and the movable contact 215 may be provided in contact with each other. The diaphragm 213 is a thin sheet made of a material that is easily deformed by slight pressure and easily restored to its original state when no pressure is applied, such as polyurethane. The movable contact 215 and the fixed contact 214 constitute a switch that is an example of a detection means.
Nozzle 212 is also connected to nozzle 17 by tube 18'.

The micro-pressure sensor 21 configured as described above can detect both exhalation and inhalation due to breathing. When detecting exhaust air, the nozzle 2 is connected through the pipe 18'.
The diaphragm 213 is deformed so as to bulge toward the movable contact 215 due to the air pressure caused by the exhaust gas guided to the diaphragm 213 . As a result, the movable contact 215 is pressed by the diaphragm 213, and the fixed contact 215 is pressed by the diaphragm 213.
4. Therefore, the movable contact 215 and the fixed contact 214 perform an electrical switching operation to detect the exhaust pressure caused by breathing. On the other hand, when detecting intake air, the intake air is detected from the nozzle 212'.
Air is sucked in from the nozzle 212 side, and this suction pressure causes the diaphragm 213 to move to the movable contact 215.
It deforms to the side and presses the movable contact 215. Therefore, the movable contact 215 and the fixed contact 214 perform an electrical switching operation, thereby detecting the intake pressure.

Note that the housing 211 may be provided with only relatively small intake and exhaust holes without providing the nozzle 212'.

Next, the configuration of the low pressure sensor 22 will be explained with reference to FIG. 2b. The low pressure sensor 22 includes a housing 221. Nozzles 22 are provided on both left and right sides of the housing 221.
2, 222' is formed, and a chamber is formed therein, and a diaphragm 223 is provided in the chamber in parallel along both side walls. A photoelectric sensor including a light emitting section 224 and a light receiving section 225 is provided approximately at the center of the diaphragm 223 . The light emitting section 224 always illuminates one side of the diaphragm 223. Light receiving section 2
25 receives the light emitted from the light emitting part 224 when it is reflected by the diaphragm 223.

In a state where exhaust pressure does not flow in from the nozzle 222, the diaphragm 223 does not deform, and therefore the light receiving section 225 derives a constant output voltage based on the reflected light. However, when the exhaust pressure flows in from the nozzle 222, the diaphragm 223 is deformed as shown by the dotted line, so that the reflection angle of the light beam emitted from the light emitting section 224 is deviated. Accordingly, the amount of light received by the light receiving section 225 changes, so the output of the light receiving section 225 changes in correlation with the deformation of the diaphragm 223. With this, diaphragm 2
The exhaust state based on the deformation of 23 is optically detected. Note that since the direction of deformation of the diaphragm 223 is reversed even in the case of intake, the low pressure sensor 22 can detect the deformation state of the diaphragm 223 using the light receiving section 225.

Note that as specific examples of the light emitting section 224 and the light receiving section 225, a light emitting diode and a photodiode (or a phototransistor) may be used, or a photocoupler in which the light emitting section and the light receiving section are integrally configured may be used.

As yet another example of the low pressure sensor, an ultrasonic detector is provided as the detection means, and the diaphragm 223
It may also be possible to detect a change in the distance between the ultrasonic detector and the diaphragm 223 based on deformation due to intake and exhaust of the diaphragm 223.

The low pressure sensor configured as described above has a tube 1
8' is connected to the back side connection part of the nozzle 17,
Alternatively, the nozzles 212 and 222 are inserted into holes in the front panel 11 and exposed on the front side, thereby replacing the nozzles 17.

FIG. 3 is a circuit diagram of an embodiment of this invention.
In the configuration, the circuit of this embodiment includes a time constant circuit 31 as an example of time-correlated signal generating means, a level discrimination circuit 33 as an example of abnormality detecting means, a light emitting diode 14 or speaker 344 as an example of notification means, and an example of driving means. , a transistor 361 or a relay 362, a contact 363, a sound generating means 34, and a reset circuit 35.

FIG. 4 is a waveform diagram for explaining the operation of FIG. 3.

Next, the operation of this embodiment will be explained with reference to FIGS. 1 to 4. First, the operation will be described when the light emitting diode 13 displays an indication or the speaker 344 generates a tone every time the patient breathes. In this case, selection switch 15 is switched to the off position, thereby disabling charging of capacitor 314. Also, one end of the tube 18 is inserted into the patient's nose or mouth. Each time the patient breathes, the micro-pressure sensor 2
1 or 22 performs a switching operation. Now, assuming that the fixed contact 214 and the movable contact 215 are in electrical contact, the current from the power supply (+V) flows through the resistor 321 - light emitting diode 13 - micro pressure sensor 2.
The light flows through the contacts 215 and 214 (referred to as a switch) of 1, and the light emitting diode 13 emits light. At this time, since the relay coil 362 is not excited, the relay switch 362 is switched to the b contact. Therefore, the low frequency oscillation circuit 34
1 is grounded via the switch of the low pressure sensor 21, and therefore the low frequency oscillation circuit 341
performs an oscillating operation while the switch of the low pressure sensor 21 is closed. This oscillation output is given as the base input of the amplification transistor 343 via the resistor 342, so the oscillation output is amplified and output to the speaker 34.
4 is generated as a dial tone. Note that if it is necessary to adjust the volume, a variable resistor is used as the resistor 342, and the resistance value is varied by the volume adjustment knob 16.

On the other hand, when the switch of the low pressure sensor 21 is opened, a relatively high voltage is applied to the cathode of the light emitting diode 13 and the input terminal of the low frequency oscillation circuit 341 via the bias resistor 322. For this reason,
The light emitting diode 13 stops displaying light, and the low frequency oscillation circuit 341 stops its oscillation operation.

Thereafter, in the same manner, each time the patient breathes, the pressure caused by inhalation or exhaustion causes the switch of the low pressure sensor 21 to open or close, and the light emitting diode 13
emits light intermittently, and the low frequency oscillation circuit 341 oscillates intermittently to generate a tone from the speaker 343.

Next, we will describe the operation that characterizes this invention, that is, the operation when detecting an abnormal state when no breath is taken within a certain unit time. When detecting an abnormal state based on the presence or absence of breathing in a certain unit time, operate the selection switch 15 to select the desired unit time (15 seconds, 30 seconds, or 60 seconds), and then select the desired unit time. Resistance 311 corresponding to time
313 is connected to the cathode of the light emitting diode 13 via the selection switch 15. Here, the resistors 311 to 315 are selected to have different resistance values in order to obtain a signal (analog signal) with a time constant correlated to a desired unit time. That is, the resistance values of the resistors 311 to 313 are selected such that the time constant based on the capacitance of the capacitor 314 and the respective resistance values becomes a desired unit time.
For example, if the unit time is selected to be 15 seconds, the selection switch 15 is switched to the resistor 311. Then, at the timing when the switch of the low pressure sensor 21 is closed, the cathode voltage of the light emitting diode 13 becomes the ground potential. Therefore, transistor 352 included in reset circuit 35 becomes non-conductive. In response, the collector end of transistor 352 has a relatively high potential due to the power supply voltage applied via bias resistor 353, so transistor 354 becomes conductive. As a result, the charge in the capacitor 314 is discharged through the transistor 354.

On the other hand, when the switch of the low pressure sensor 21 is opened, a current from the power supply flows through the bias resistor 322, the selection switch 15, the resistor 311, and the capacitor 314, and charges the capacitor 314. At this time, since a relatively high voltage is applied to the transistor 352, the transistor 352 becomes conductive and therefore the transistor 354 becomes non-conductive. As a result, discharging of capacitor 314 is stopped and capacitor 314 is charged.

As mentioned above, in a state where the capacitor 314 is charged, if the patient breathes before the unit time T that correlates to the time constant determined by the resistance value of the resistor 311 and the capacitance of the capacitor 314 has elapsed,
The switch of the low pressure sensor 21 is closed again. Accordingly, the cathode end of the light emitting diode 13 is grounded, and the light emitting diode 13 emits light. At the same time, the low frequency oscillation circuit 341 operates to oscillate.
Generates a beep intermittently. In addition, in response to the closing of the switch of the low pressure sensor 21, the transistor 3
52 becomes non-conductive and transistor 354 becomes conductive, so that the charge in capacitor 314 is discharged. Therefore, the terminal voltage of the capacitor 314 does not reach the discrimination level preset by the level discrimination circuit 33, and the level discrimination circuit 33 does not derive an abnormality detection output.

On the other hand, if the patient does not breathe once during the elapse of unit time T from when the charge in the capacitor 314 is discharged, the capacitor 314 is continuously charged. Therefore, the terminal voltage of capacitor 314 gradually increases and eventually exceeds the discrimination level. In response, the level discrimination circuit 33 derives an abnormality detection signal (high level) and makes the transistor 361 conductive via the resistor 323. Therefore, current from the power source flows through relay coil 362 - transistor 361 - light emitting diode 14 . In response, the light emitting diode 14 emits light to notify the abnormal state. At the same time, the relay coil 362 is energized and the relay switch 363 is activated.
Switch to the a contact side. That is, the relay switch 363 continuously grounds the input terminal of the low frequency oscillation circuit 341. Accordingly, the low frequency oscillation circuit 341 continuously oscillates, and transmits the oscillation output to the resistor 342.
is applied to the amplifying transistor 343 via the amplifying transistor 343 to generate a continuous tone from the speaker 344 indicating the abnormal condition. In this way, if the patient does not breathe even once within a unit time, a notification indicating the abnormal condition is given through a display or a beep.

As described above, according to this invention, the intake or exhaust air from the patient's breathing is guided to the micro-pressure sensor, and the breathing state is detected by the deformation of the diaphragm of the micro-pressure sensor, making it extremely safe and highly sensitive. It has the effect of being able to detect the respiratory state, without being affected by ambient temperature, and when used in conjunction with an anesthesia mask. Furthermore, according to this invention, 1 time per unit time
This has the effect of reliably detecting abnormal conditions such as not breathing frequently.

[Brief explanation of the drawing]

FIG. 1 is an illustrative diagram of a respiratory monitoring device according to an embodiment of this invention. FIG. 2 is a detailed illustration of the low pressure sensor used in the respiratory monitoring device of this invention. FIG. 3 is a circuit diagram of an embodiment of this invention. FIG. 4 is a waveform diagram for explaining the operation of FIG. 3. In the figure, 10 is a respiratory monitoring device, 13 is a light emitting diode, 14 is a light emitting diode (display means), 15 is a selection switch (period setting means), 1
8, 18' are tubes, 21, 22 are low pressure sensors, 31
3 is a time constant circuit (time correlation signal generating means), 33 is a level discrimination circuit (abnormality detecting means), 34 is a sound generating means, and 35 is a reset circuit.

Claims (1)

[Claims for Utility Model Registration] (1) A main body, a nozzle provided in relation to the main body for allowing gas to enter and exit the main body, and a micro-pressure sensor housed in the main body, The micro-pressure sensor includes a sheet-shaped diaphragm that is deformed by micro-pressure caused by breathing and restores its shape when the micro-pressure is not applied, and a housing that includes a chamber that houses the diaphragm, and the chamber communicates with the nozzle. and a detection means provided in the housing and configured to detect deformation of the diaphragm and derive a switching signal, further having one end coupled to the nozzle and the other end detecting the intake and exhaust of the subject. a tube placed in the sensing area; a period setting means for setting a period at which an abnormal state should be detected when the subject's intake or exhaust does not occur for a certain period of time; generating a signal correlated to the elapsed time; time correlation signal generation means that is reset in response to a switching signal output from the detection means; the output signal of the time correlation signal generation means exceeds a time period corresponding to an abnormal state detection period set by the period setting means; an abnormality detection means that outputs an abnormality detection signal when detecting an abnormality, a notification means that notifies that the respiratory state of the subject is abnormal, and drives the notification means in response to the abnormality detection signal of the abnormality detection means. A respiratory monitoring device having a drive means for (2) The breathing monitor device according to claim 1, wherein the notification means is a display means for notifying abnormal conditions in a visually recognizable manner. (3) The breathing monitor device according to claim 1, wherein the notification means is a means for notifying abnormal conditions in an audibly recognizable manner.