JPH0838603A - Inhalation air supply system for generating air flow depending on moisture - Google Patents

Abstract

PURPOSE: To enhance reliability by controlling to increase humidity or temperature or both more than the base value where air flowing volume decreases as a result of an increased resistance in respiratory tract or where air flowing volume increases as a result of air leaks. CONSTITUTION: By actuation of a pressure blower against a positive resistance in the respiratory tract, air is introduced through a tube 1 into an inlet 2 of a moisturizing chamber 3 which gives moisture to be evaporated at a heating base 4. Thus, the moistened air is discharged from an outlet 5 and fed to a mask 8 covering a patient's face through a tube 7. In the connector 11 connected to the face mask 8, a reformed orifice and two pressure converters 12, 13 positioned on the side surfaces of the orifice are installed. According to the output signals generated, a resistance in the respiratory tract is detected by a controller 9 and when an increase in the resistance of the respiratory tract is detected, the humidity of air to be supplied to the patient is increased.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a respiratory air supply system with a moisture component. In particular, it relates to systems in which the humidity and / or temperature of the supplied air is a function of the airflow flowing through the system.

[0002]

BACKGROUND OF THE INVENTION External air supply is considered necessary to support a patient's respiratory action in a variety of environments. Another device is used to provide a positive flow of air. For air supplied to the patient's mouth or throat, ventilation is used. Continuous positive pressure for air supplied to the nose
(CPAP) blower is used. In both cases, for different reasons, it is often desirable that the air supplied be moist.

[0003]

It has been discovered that it is preferable to adjust the humidity of the air supplied to the nose according to variations in flow rate and / or nasal airway resistance (NAR). It has also been discovered that mouth leakage leads to NAR. However, adjusting the humidity with respect to the direction of mouth leakage may prevent or reduce incidents of nasal airway resistance (NAR).

[0004] A typical situation is the use of nasal CPAP (nCPAP) during surgery on obstructive sleep-absorptive patients.

[0005]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide an inhalation or breathing air supply system which realizes the aforementioned discovery. Therefore, in one embodiment, the invention provides a method of supplying air for inhalation or breathing to a patient, by humidifying the air supplied to the patient and sensing the above-mentioned air flow to detect the airway of the patient. Detect changes in resistance,
By increasing the humidity and / or temperature when an increase in airway resistance is detected and lowering the humidity and / or temperature when a decrease in airway resistance is detected, the humidity and / or temperature of the air as described above It consists of steps that control both.

[0006] In yet another aspect of the invention, a device for supplying humidified inhalation or breathing air to a patient from an external source corresponding to controllable humidity and temperature. An electronic controller for humidifying means for humidifying the supplied air and for said humidifying means for determining the humidity and temperature of the air leaving said humidifying means, the input receiving a signal indicative of a patient's airway resistance. The above-mentioned controller equipped with the above, the above-mentioned breathing face mask used for the patient, the air supply tube for connecting the output of the above-mentioned humidifying means to the above-mentioned face mask, and the air flow for monitoring the above-mentioned air hose flow. A converter, the output of which is at least 1
Comprising said airflow converter connected to one of the aforementioned controller inputs, wherein the controller controls the humidity of the air exiting the humidification means when said airflow converter exhibits an increase in patient airway resistance. It comprises a device as described above, which is elevated and configured to reduce the humidity of the air exiting the humidification means when the airflow converter exhibits a decrease in airway resistance of the patient.

[0007]

The present invention will be described with reference to its use in providing nasal air supply to a patient suffering from obstructive sleep desorption. Looking at FIG. 1, a source of air, in this case a continuous positive airway resistance pressure (nCPAP) blower (not shown) in the nose, is the tube that connects the air to the inlet 2 of the humidification chamber 3. Send to 1. The humidifying chamber 3 contains water vaporized by the heating base 4. The air enters the humidification chamber through the inlet 2 and exits through the outlet 5 that entrains water vapor as it is. Connector 6 is outlet 5
Is connected to a tube 7 that delivers humidified air to a mask 8 on the patient's face.

Referring also to FIG. 2, the humidification chamber 3 and the base 4 are heated by an electrical element 16 mounted on top of the humidification controller 9 and the energy delivered to the heating element is some preset. It depends on the variable and many feedback inputs. Generally, there are two return signals representing the air temperature at the outlet of the humidification element 5 (T2) and the air temperature at the patient end of the tube 7 (T1). This temperature feedback, however,
It does not form part of the invention.

In addition to controlling the heat conducted to the humidification chamber 3, the controller 9 also sends an electric current to the heating wire 17 associated with the tube 7 via the electrical connection element 10. The tube 7 is heated to prevent or reduce condensation of humidified air as it enters the patient through the tube. Face mask 8 located at the end of tube 7 and over the airway
The connector 11 which mates with a calibrator includes a calibrated orifice (not shown) and two pressure transducers 12 and 13 located on either side of the orifice. Measured pressure
The signals representing P1 and P2 are provided by pressure transducers 12 and 13, respectively, and applied as inputs 14 and 15 of controller 9. The pressure difference P1-P2, along with the calibrated orifice,
Allows the controller 9 to calculate the flow rate of air delivered to the patient via the tube 7. Generally equipped with a programmed microprocessor 18.
The controller 9 is programmed to control the heater 16 to change the humidity and / or temperature of the air entering the tube 7 from a base value of humidity as a function of the measured air flow rate. The microprocessor produces display information that is sent to the display 20 via the display driver 19. The alarm 21 can be activated by the controller when the monitored variable exceeds preset limits.

Although FIG. 2 shows the other inputs 22 of the controller, these do not form part of the invention. Reduced airflow may be due to inflammation, nasal airway resistance
Since it indicates (NAR), the controller increases the humidity of the air entering and exiting tube 7. It relieves inflammation and helps reduce NAR. Similarly, excessive air leakage from the mouth leads to an increase in NAR.

However, such an air leak will cause a detectable increase in the air flow, which will cause the controller 9 to provide the patient with the NAR increase that is expected to occur thereafter. Will increase the humidity. There, again, the controller 9 increases the humidity of the air delivered to the patient, which helps to reduce the expected dehydration episodes. When any decrease in NAR is sensed, the humidity is reduced, but not below a preset base value.

The operations performed by the microprocessor 18 are illustrated in FIGS. 3 and 4. The system is started at block 31 by setting the proper base values for flow, pressure, NAR and humidity (ambient and saturated humidity). At block 32, a determination as to whether there is a mouth leak is made from the measured flow. If not, operation proceeds from block 37 where nasal airway resistance is tested.
When a mouth leak is detected, operation proceeds to level 33, where the test is performed on the change. At level 34, the humidity of the air delivered to the patient by the humidification element is tested to check if it is already maximum or minimum.
Computation proceeds to level 35 where a decision (and later implementation) regarding humidity increase or decrease is made. The sequence stops and returns to block 32 (36). The calculation of the airway resistance of the nose (FIG. 4) is basically the same as the above calculation.

An example of a specific embodiment of the inhalation or breathing air supply system according to the present invention will be shown below. That is, as a basic mode, there is a method of supplying air for breathing to a patient, humidifying the air supplied to the patient, detecting the change in the flow of the air, and as a result of an increase in airway resistance. Humidity and / or temperature so that the humidity and / or temperature is increased above a predetermined base value when the airflow is reduced as a result of the increase or as a result of air leakage as a result of an increase in airflow. Is an inhalation or breathing air supply system including steps for controlling.

As another aspect, in the above basic system, for example, (1) an increase in the air flow indicating leakage at the mouth is detected, and if the increase is detected,
Increase the humidity, and if the increase is not detected, (2) detect a decrease in airflow that indicates an increase in airway resistance of the nose, and if that decrease is detected, change the humidity. According to the process sequence of increasing,
The operation of detecting the air flow and the operation of adjusting the humidity can be performed periodically.

In yet another embodiment, for example, a device for supplying humidified breathing air to a patient, which humidifies air supplied from an external source in accordance with controllable humidity and temperature. An electronic controller for the humidifying means and for determining the humidity and temperature of the air exiting the humidifying means, the controller comprising an input for receiving a signal indicative of air flow; A respiratory face mask for use with a patient, an air supply tube for coupling the output of the humidifying means to the face mask, and an airflow converter for monitoring the flow of the air hose, the output of which is Comprising at least one airflow converter connected to at least one of said controller inputs, wherein said controller is such that said airflow converter exhibits reduced airflow to a patient, or Is configured to control the humidity of the air exiting the humidifying means to be above a predetermined base value when the airflow converter indicates an increase in airflow to the patient. You can have it.

[0016]

Although the invention has been described using air flow rate as the main feedback variable, the use of a single pressure transducer is also considered plausible, and pressure increase will indicate increased NAR. . In addition, other transducers that provide a flow-indicating signal can be used in place of the pressure transducer / calibrated orifice combination described above.

The air source, eg a blower, is not a separate device part from the humidification element described above, but can be integrated with the humidification element to form a single unit. Alternatively, the humidification element controller can control the blower without the need for a separate blower controller. It will be appreciated from the foregoing description that the present invention is capable of providing a breathing air supply function with temperature and humidity that is optimal despite leakage and / or changes in air flow at the NAR.

[Brief description of drawings]

FIG. 1 diagrammatically shows a respiratory air supply system.

FIG. 2 shows a humidity controller electrical circuit.

FIG. 3 shows controller operations in flow chart form.

FIG. 4 illustrates controller operations in flow chart form.

[Explanation of symbols]

 1 ... Tube 2 ... Inlet 3 ... Humidifying chamber 4 ... Heating base 5 ... Outlet 6 ... Connector 7 ... Tube 8 ... Patient's face mask 9 ... Controller 10 ... Electrical connection element 11 ... Connector 12 ... Pressure transducer 13 ... Pressure transducer 14 ... input 15 ... input 16 ... heater plate

Claims (5)

[Claims] 1. A method of supplying breathing air to a patient, the method comprising humidifying the air supplied to the patient, detecting a change in the air flow, wherein the air flow is increased as a result of an increase in airway resistance. If it decreases,
Alternatively, each step includes controlling the humidity and / or temperature such that the humidity and / or temperature are increased above a predetermined base value if the airflow increases as a result of air leakage. The above method. 2. The method of claim 1 wherein air is delivered to the patient's nose and the sensed airway resistance is nasal airway resistance. 3. (1) An increase in airflow indicating leakage at the mouth is detected. If an increase is detected, the humidity is increased. If no increase is detected, (2) According to the process sequence of detecting a decrease in the air flow indicating an increase in the airway resistance of the nose and increasing the humidity if the decrease is detected, the operation for detecting the air flow is performed. The method according to claim 2, characterized in that the operation for adjusting the humidity and the humidity are performed periodically. 4. A device for supplying humidified breathing air to a patient, comprising: humidifying means for humidifying air supplied from an external source in accordance with controllable humidity and temperature; and the humidifying means. An electronic controller for the humidifying means for determining the humidity and temperature of the exiting air, the controller comprising an input for receiving a signal indicative of air flow, and a respiratory face mask for use with the patient. An air supply tube for coupling the output of the humidifying means to the facial mask, and an airflow converter for monitoring the flow of the air hose, the output of which is connected to at least one of the controller inputs. And wherein the controller is configured to indicate that the airflow converter has reduced airflow to the patient, or the airflow converter has airflow to the patient. Of to indicate increase, and is configured to control so as increase than the base value set in advance the humidity of the air exiting the humidifying means, the device. 5. The air flow converter comprises a calibrated orifice in communication with the air supply tube, a first pressure converter located upstream of the orifice, and a downstream pressure of the orifice. A second pressure transducer, the first and second transducers each sending a signal to a respective controller input, the controller directing an air flow to 2
The foregoing apparatus programmed to calculate from two pressure signals and orifice parameters.