CN113712533A

CN113712533A - Side stream exhales end and exhales end carbon dioxide monitoring devices

Info

Publication number: CN113712533A
Application number: CN202110947585.8A
Authority: CN
Inventors: 许天罡
Original assignee: Suzhou Troline Electronic Technology Co ltd
Current assignee: Suzhou Troline Electronic Technology Co ltd
Priority date: 2021-08-18
Filing date: 2021-08-18
Publication date: 2021-11-30

Abstract

The invention belongs to a side-stream end-call carbon dioxide monitoring device, which comprises: the sampling gas circuit is used for connecting the mouth and the nose of a patient; the first air inlet of the three-way electromagnetic valve is communicated with the sampling air path; the carbon dioxide filtering device is used for eliminating carbon dioxide gas in the air; the carbon dioxide filtering device is connected with a second air inlet of the three-way electromagnetic valve; the photoelectric monitoring module is arranged at the downstream of the three-way electromagnetic valve in the airflow direction; the air pump is installed photoelectric monitoring module low reaches for the extraction air is so that the air flow through carbon dioxide filter equipment, air flow through behind the carbon dioxide of filtering the three-way solenoid valve with wait for the photoelectric monitoring module of zero calibration, this application scheme is zero calibration precision higher for prior art.

Description

Side stream exhales end and exhales end carbon dioxide monitoring devices

Technical Field

The invention relates to a device for acquiring end-tidal carbon dioxide data, in particular to a device for zero calibration of carbon dioxide.

Background

The end-tidal carbon dioxide monitoring equipment is used for monitoring end-tidal carbon dioxide of a human body, and the end-tidal carbon dioxide can reflect lung ventilation and can also reflect physiological indexes such as lung blood flow and the like.

The zero calibration is needed after the end-call carbon dioxide monitoring device is used for a long time. The existing zero-comparing method is divided into two types. One zeroing method is to manually take one end of the collecting tube to a place far away from pollution sources such as the mouth and the nose 104 of a person to wait for sampling a section of air for zeroing. This solution has two drawbacks: the first requires manual work to handle. The second air still has CO2 with a relatively low concentration, and the zero calibration also causes inaccurate data of the end-expiratory carbon dioxide monitoring data in a certain error.

Another current zeroing scheme is to automatically switch with solenoid valves, but this scheme usually places a relatively zero bleed port inside the module or on the outside of the module. The environment where the respiratory carbon dioxide module works is often a high CO2 gas pollution environment, and is close to a patient, or even an operation, a great number of CO2 gas pollution sources are arranged around the equipment, and the result of the scheme is 0, so that a great error is caused, and if the pollution gas around the equipment is high, the equipment is even repeated to zero and cannot work.

Even if the second solution can optimize the air path to provide a clean air source, the zero calibration error is also generated due to the carbon dioxide in the air.

Disclosure of Invention

The invention aims to provide an automatic carbon dioxide zero calibration device which can filter carbon dioxide in air so that a detection result of a carbon dioxide optical detection module is more accurate.

Specifically, the invention provides a side-stream end-expiratory carbon dioxide monitoring device, comprising:

the sampling gas circuit is used for connecting the mouth and the nose of a patient;

the first air inlet of the three-way electromagnetic valve is communicated with the sampling air path;

the carbon dioxide filtering device is used for eliminating carbon dioxide gas in the air; the carbon dioxide filtering device is connected with a second air inlet of the three-way electromagnetic valve;

the photoelectric monitoring module is arranged at the downstream of the three-way electromagnetic valve in the airflow direction;

and the air pump is arranged at the downstream of the photoelectric monitoring module and used for pumping air so as to enable the air to flow through the carbon dioxide filtering device, and the air after being filtered to remove carbon dioxide flows through the three-way electromagnetic valve and the photoelectric monitoring module waiting for zero calibration.

In a preferred embodiment of the present application, the carbon dioxide filter device includes a polymer membrane, and the polymer membrane filters carbon dioxide in air.

In a preferred embodiment of the present application, the carbon dioxide filter unit comprises a carbon dioxide absorbent.

In a preferred embodiment of the present application, the optoelectronic monitoring module includes an optoelectronic sensor and a processor.

In a preferred embodiment of the present application, the photosensor comprises a light emitting diode and a light monitoring sensor, the light emitting diode emitting light of a first frequency and light of a second frequency; the first frequency light can be attenuated with the concentration of carbon dioxide, and the second frequency light is not attenuated with the concentration of carbon dioxide; the light monitoring sensor includes a first receiver capable of sensing light at the first frequency and a second sensor capable of sensing light at a second frequency.

In a preferred embodiment of the present application, the first receiver surface is covered with a first filter for filtering out light of a first frequency from the light emitted from the light emitting diode; the surface of the second receiver is covered with a second filter film for filtering out light with a second frequency from the light emitted by the light emitting diode.

In a preferred embodiment of the present application, the processor is configured to acquire carbon dioxide concentration data from the sensor, or to control the photosensor to zero.

In a preferred embodiment of the present application, the three-way solenoid valve is controlled by the processor, and the solenoid valve is connected to the carbon dioxide filtering device and the photoelectric monitoring module when zero calibration is performed.

In a preferred embodiment of the present application, the gas pump is controlled by the processor to operate the pump to enable the gas to flow when the time zero is zero.

According to the invention, the carbon dioxide filtering device can filter carbon dioxide in air, and the time calibration of the photoelectric detection module is more accurate. Meanwhile, the calibration process is fully automatic, medical personnel are not needed to intervene, and the use burden of a user is reduced.

Drawings

Fig. 1 is a schematic diagram of the overall structure of a side-stream end-tidal carbon dioxide monitoring device.

Fig. 2 is a schematic view of a carbon dioxide filter unit.

Fig. 3 is a schematic structural diagram of a photoelectric detection module.

Fig. 4 is a schematic diagram of a breath end carbon dioxide zero-checking procedure.

Detailed Description

The following detailed description of the embodiments of the present invention will be provided to assist those skilled in the art in understanding the spirit of the present invention.

Fig. 1 shows a schematic diagram of the overall structure of an end-tidal carbon dioxide monitoring device 100. Which are merely illustrative of the principles of operation thereof, and one skilled in the art can implement various embodiments in accordance with the principles of operation illustrated.

The device for monitoring the end-expiratory carbon dioxide comprises a sampling gas circuit 102, a three-way electromagnetic valve 108, a carbon dioxide filtering device 104, a photoelectric detection module 110 and an air pump 112. The end-tidal carbon dioxide monitoring device 100 can be used as a stand-alone carbon dioxide detection device, and can also be used as a sensor accessory for a care facility such as a ventilator. When used as a stand-alone device, the end-call carbon dioxide monitoring apparatus 100 is provided with a human-computer interface that provides a zero calibration triggering mechanism to enable a user to manually calibrate the device.

In the following, the main components of the present invention will be described, respectively, by taking as an example the use of the end-tidal carbon dioxide monitoring apparatus 100 as a sensor accessory of a care device such as a ventilator.

And a sampling gas circuit 102 for connecting with the mouth and nose 104 of the patient. Sampling circuit 102 a user ventilator or like device provides breathing gas to a patient, typically a flexible tube as the main circuit. The carbon dioxide detection equipment extracts gas in the main gas circuit, detects the content of carbon dioxide in the gas and sends detected carbon dioxide data to the breathing machine.

And the three-way electromagnetic valve 108 is used for switching the gas circuit when the carbon dioxide detection equipment works in a zero calibration state and a detection state. The three-way solenoid valve 108 includes a first inlet port 114, a second inlet port 116, and an outlet port 118, which may select whether the first inlet port 114 communicates with the outlet port 118 or the second inlet port 116 communicates with the outlet port 118 under the control of the processor 314. When the end-expiratory carbon dioxide detection device works normally, the first air inlet 114 is communicated with the sampling air path 102, and the expired air generated by human or animals passes through the photoelectric detection module 110. When the carbon dioxide detection device is calibrated, the electromagnetic valve switches the gas circuit to enable the second gas inlet 116 to be communicated with the gas outlet 118, and the gas outlet 118 is connected with the carbon dioxide detection module.

Fig. 2 is a schematic diagram of two embodiments of the carbon dioxide filter 104.

And the carbon dioxide filtering device 104 is used for eliminating carbon dioxide gas in the air when the carbon dioxide detection device is zero. The carbon dioxide filtering device 104 is connected with the second air inlet 116 of the three-way electromagnetic valve 108, the carbon dioxide filtering device 104 shown in the carbon dioxide filtering device 104a comprises an airtight shell 202, a hollow cavity 204 is arranged inside the shell 202, the cavity 204 comprises air inlets (114, 116) and an air outlet 118, the air inlet 114 is communicated with air, and the air outlet 118 is connected with the second air inlet 116 of the three-way electromagnetic valve 108. The hollow cavity is internally provided with a polymeric carbon dioxide filter membrane 206, and the polymeric filter membrane 206 includes but is not limited to: poly 4-methyl-1-pentene membranes, polyethersulfone membranes, polyimide membranes, and the like; the upstream of the air flow of the high-molecular filter membrane is provided with a particle filtering layer which filters dust in the air, and the particle filtering layer is preferably a HEPA filter and is used for filtering micron-sized particles in the air.

Optionally, a carbon dioxide absorbent 208 may be included in carbon dioxide filter device 104b, and carbon dioxide absorbent 208 combines with carbon dioxide to form new compounds, thereby fixing the carbon dioxide within the absorbent. The carbon dioxide absorbent 208 is calcium hydroxide.

And the photoelectric monitoring module 110 is used for detecting the content of carbon dioxide in the gas. Is arranged at the downstream of the air outlet 118 of the three-way electromagnetic valve 108 in the air flow direction. The photodetection module 110 determines the content of carbon dioxide in the gas by emitting detection light and detecting the attenuation of the detection light.

An air pump 112 is arranged downstream of the photoelectric detection module 110 in the air flow direction, and the air pump 112 is used for pumping air so as to enable the air to flow through the carbon dioxide filtering device 104, and after being filtered out of carbon dioxide, the air flows through the three-way electromagnetic valve 108 and the photoelectric detection module 110 waiting for zero calibration.

Fig. 3 is a schematic circuit diagram of the carbon dioxide detecting device. Which includes a processor 314, a light emitting diode 320 connected to the processor 314, and a photosensor for receiving light. The photoelectric sensor comprises a first sensor 306 and a second sensor 308, the output signals of the first sensor 306 and the second sensor 308 are connected with an amplifier 310, the output signal of the amplifier 310 is connected with an ADC312, the output signal of the ADC312 is connected with a processor 314, and a filter can be connected between the amplifier 310 and the ADC module 312 to eliminate noise interference. Optionally, the processor 314 is connected to a communication module 318, and the communication module 318 is connected to the ventilator by wire or wirelessly. The processor 314 is connected to the three-way solenoid valve 108 and the air pump 112 to control the air path switching action of the three-way solenoid valve 108 and the start and stop action of the air pump 112.

Fig. 4 is a flow chart of the carbon dioxide zero calibration test. The working state of each module in the carbon dioxide zero calibration process is further described below with reference to fig. 3.

In step 402, the processor 314 sends a control signal to the three-way solenoid valve 108 to cause the solenoid valve to connect the second air inlet 116 and the photo detection module 110. The processor 314 can also send control signals to cause the solenoid valve to connect the first inlet port 114 to the ventilator after zeroing is complete.

In step 404, the processor 314 sends a control signal to activate the air pump 112. In fig. 3, the air pump 112 is provided with a driving circuit, and the processor 314 controls the start and stop of the air pump 112 by sending a switch signal to the driving circuit. After the air pump 112 is started, air enters the carbon dioxide filtering device 104 from the outside and then enters the photoelectric detection module 110.

In step 406, the air pump 112 is activated and the processor 314 delays for a period of time before proceeding to the next step. This delayed first time is used for the air pump 112 to pump out the "old air" existing in the three-way solenoid valve 108 of the photodetection module 110 and the carbon dioxide filtering device 104 so as not to affect the zeroing precision. Usually the first time of said delay can be set from a few seconds to a few tens of seconds.

In step 408, the processor 314 controls the LED 320 to emit light after a first time. The light emitted by the LED light source includes a first frequency of light l1 and a second frequency of light l 2. The first frequency light and the second frequency light simultaneously pass through the air for zero calibration. The first frequency light is capable of attenuating with carbon dioxide concentration and the second frequency light is not attenuating with carbon dioxide concentration.

In step 410, the photosensor includes a first receiver capable of sensing light at the first frequency, and a second sensor 308 capable of sensing light at a second frequency. The surface of the sensor of the first receiver is covered with a first filter film, and the surface of the second receiver is covered with a second filter film. The first filter allows the light ray l1 to be transmitted, the second filter allows the light ray l2 to be projected, and the first sensor 306 and the second sensor 308 convert the light signals of l1 and l2 into electric signals.

In step 412, the electrical signals generated by the first sensor 306 and the second sensor 308 are converted by the amplifier 310 and the ADC to form a digital signal that can be read by the processor 314, and the processor 314 takes the value M0 of the digital signal as a zero value. Processor 314 then turns off air pump 112 and resets three-way solenoid valve 108, which three-way solenoid valve 108 re-directs sampling circuit 102 to the ventilator.

It should be noted that the verification process may also be performed during normal operation of the ventilator. For example, if the system is triggered to zero by the operator, and the system is performing real-time carbon dioxide detection normally, and the air pump 112 is already on, the control flow may skip step 404 directly. After the detection is complete, the solenoid valve is simply reset in step 408, and the system immediately reenters the carbon dioxide concentration measurement state and sends the data to the ventilator in real time.

The first frequency ray l1 is absorbed by carbon dioxide and the second frequency ray is not absorbed by carbon dioxide when the carbon dioxide concentration measurement is made. Therefore, the intensity of the first frequency light l1 is reduced relative to the second frequency light l 2. So that the difference M1 between the first frequency light l1 and the second frequency light becomes large. And obtaining a value delta M representing the concentration of the carbon dioxide by subtracting the M1 from a zero value M0, and obtaining an actual concentration value of the carbon dioxide corresponding to the delta M by a table look-up method and the like.

The application has got rid of the carbon dioxide in the air through the mode of filtering and has reduced the influence of fluctuation of carbon dioxide concentration in the air to system monitoring precision, and whole school zero process automation does not need medical personnel's intervention to use manpower sparingly simultaneously.

Claims

1. A side-stream end-tidal carbon dioxide monitoring device, comprising:

2. The device of claim 1, wherein the carbon dioxide filter unit comprises a polymeric membrane, and the polymeric membrane filters carbon dioxide from air.

3. The device for monitoring end-tidal carbon dioxide of a by-pass flow according to claim 1, wherein the carbon dioxide filter device comprises a carbon dioxide absorbent.

4. The device of claim 1, wherein the optoelectronic monitoring module comprises an optoelectronic sensor and a processor.

5. A bypass flow end-call carbon dioxide monitoring device according to claim 3, wherein the photo sensor comprises a light emitting diode and a light monitoring sensor, said light emitting diode emitting light of a first frequency and light of a second frequency; the first frequency light can be attenuated with the concentration of carbon dioxide, and the second frequency light is not attenuated with the concentration of carbon dioxide; the light monitoring sensor includes a first receiver capable of sensing light at the first frequency and a second sensor capable of sensing light at a second frequency.

6. The device of claim 5, wherein the first receiver surface is covered with a first filter for filtering light of a first frequency from the light emitted from the light emitting diode; the surface of the second receiver is covered with a second filter film for filtering out light with a second frequency from the light emitted by the light emitting diode.

7. The device of claim 3, wherein the processor is configured to obtain carbon dioxide concentration data from the sensor or to control the photoelectric sensor to zero.

8. The device of claim 7, wherein the three-way solenoid valve is controlled by the processor, and the solenoid valve is connected to the carbon dioxide filter and the optoelectronic monitoring module when the time is zero.

9. The device of claim 8, wherein the pump is controlled by the processor to operate pumping to cause gas flow when the timing zero is zero.