Method for controlling ventilator according to the wearing of a cannula

Abstract

A method for automatically controlling the supply flow rate of a ventilator according to the wearing status of a cannula worn by a patient is disclosed. The control method of a ventilator according to the present invention, which controls the mixing of oxygen and ambient air to generate a mixed gas and to allow the generated mixed gas to flow into the patient's airway through a cannula, comprises the steps of: a flow measurement sensor measuring the actual respiratory flow rate flowing into the patient's airway through the cannula; a control device checking the number of times the actual respiratory flow rate measured by the flow measurement sensor deviates from a reference value over a certain period of time; a control device determining whether the reference upper limit or reference lower limit has been exceeded if the number of times the actual respiratory flow rate deviates from the reference value is k or more; a control device determining the wearing status of the cannula based on the determination result; and a control device controlling the supply flow rate of the ventilator to decrease or increase according to the wearing status of the cannula.

Description

Technology Field

[0001] The present invention relates to a method for controlling the supply flow rate of a ventilator according to the wearing state of a cannula. Background Technology

[0002] In general, ventilators are important oxygen therapy devices widely used not only for patients with lung disease but also for patients who, due to various conditions, are unable to breathe on their own a tidal volume that sufficiently exceeds their dead space.

[0003] Ventilators are classified into low-flow and high-flow systems depending on the method of oxygen administration, and they are a non-invasive method of supplying oxygen to a patient's airway, whether at a low or high flow rate.

[0004] The low-flow method is a simple method of supplying a low flow rate of oxygen and is easy to use. However, since it supplies only a portion of the inhaled air that the patient breathes, it has the disadvantage that the partial pressure of oxygen varies depending on the breathing pattern because air from the atmosphere is mixed in.

[0005] High flow rate is a method of continuously supplying a constant partial pressure of oxygen regardless of changes in the patient's breathing pattern, and is widely used in oxygen therapy for critically ill patients with irregular breathing patterns. However, it has the disadvantage of not being able to supply oxygen concentrations of 50% or higher, and insufficient humidification and heating due to excessive flow rates.

[0006] The non-invasive method involves supplying oxygen to the airway using a mask or cannula while the patient is conscious, while the invasive method involves supplying oxygen to the airway using endotracheal intubation or a tracheostomy. If non-invasive oxygen supply is attempted but an oxygen concentration of 50% or higher is required or if the patient's symptoms or disease worsen, invasive mechanical ventilation may be performed.

[0007] As such, when patients are unable to maintain adequate breathing through their own breathing efforts, they receive artificial respiration treatment; mild cases are treated with a low-flow nasal cannula, severe cases with a high-flow nasal cannula, or by using an invasive method.

[0008] However, in the case of nasal cannulas, there is a problem in that the respiratory flow rate entering the patient's airway is inconsistent because the fit is not the same for every patient.

[0009] For example, if the cannula is fitted too tightly, the inspiratory flow rate entering the patient's airway becomes greater than the flow rate supplied by the ventilator. While this may be beneficial for the patient's nasal ventilation, it increases expiratory resistance, causing difficulties for the patient to exhale comfortably.

[0010] When the cannula is detached from the patient's nose, the actual inspiratory flow rate entering the patient's airway becomes much smaller than the flow rate supplied by the ventilator due to flow loss. This presents a problem in that the effectiveness of respiratory therapy is reduced, and in some cases, respiratory support for the patient may not be provided efficiently.

[0011] Therefore, during respiratory therapy for patients, there is the inconvenience of clinicians having to individually check the fit of the cannula and, in the case of severe patients, determine the therapeutic flow rate while periodically monitoring observational data such as changes in respiratory rate.

[0012] A related prior art document is Korean Registered Patent Publication No. 10-2641547 (Title of invention: Device for extracting patient flow in a high-flow therapy device using a cannula, Registration date: 2024.02.22.). Prior art literature

[0013] Korean Patent Publication No. 10-2641547 (February 22, 2024) Korean Patent Publication No. 20-0496651 (March 22, 2023) The problem to be solved

[0014] The object of the present invention is to provide a method for automatically controlling the respiratory flow rate of a ventilator according to the wearing status of a cannula worn by a patient.

[0015] In particular, the present invention aims to enable smooth respiratory treatment for a patient without requiring individual verification by a clinician (or medical staff) by checking the actual respiratory flow rate entering the patient's airway through the cannula to indirectly analyze the cannula's fit and controlling the supply flow rate of the ventilator to decrease or increase according to the cannula's fit. means of solving the problem

[0016] The above objective is achieved by a method for controlling a ventilator according to the wearing state of a cannula, according to an embodiment of the present invention, wherein the method comprises: a step in which a flow measurement sensor measures the actual respiratory flow rate entering the patient's airway through the cannula; a step in which a control device checks the number of times the actual respiratory flow rate measured by the flow measurement sensor deviates from a reference value during a certain period of time; a step in which the control device determines whether the reference upper limit or reference lower limit has been exceeded if the number of times the actual respiratory flow rate deviates from the reference value is k or more; a step in which the control device determines the wearing state of the cannula according to the determination result; and a step in which the control device controls the supply flow rate of the ventilator to decrease or increase according to the wearing state of the cannula.

[0017] Preferably, in the step of determining the wearing state of the cannula, if the number of actual breathing flow rates deviating from the reference value is k or more and exceeds the reference upper limit, the wearing state of the cannula is determined to be an over-tight fit and is controlled to indicate this.

[0018] If the number of actual breathing flow rates deviating from the above standard is k or more and exceeds the above standard lower limit, the wearing status of the cannula is determined to be detached and controlled to display this.

[0019] Preferably, the step of controlling the supply flow rate of the ventilator to decrease or increase is to control the supply flow rate of the ventilator to decrease when the cannula is in an over-tight state, and to control the supply flow rate of the ventilator to increase when the cannula is in a detached state.

[0020] Preferably, a method for controlling a ventilator according to the wearing state of a cannula according to one embodiment of the present invention may further include a step of controlling the control device to determine that the wearing state of the cannula is good and to indicate this if the number of actual breathing flow rates deviating from the reference value is less than k times.

[0021] Preferably, a method for controlling a ventilator according to the wearing state of a cannula according to one embodiment of the present invention may further include, after the step of controlling the supply flow rate of the ventilator, the step of the control device measuring the oxygen saturation of a patient and analyzing whether the oxygen saturation measurement value is within a normal range; and the step of the control device calling a clinician if the oxygen saturation measurement value is outside the normal range. Effects of the invention

[0022] According to an embodiment of the present invention, by checking the actual respiratory flow rate entering the patient's airway through the cannula to indirectly analyze the cannula's wearing status and controlling the supply flow rate of the ventilator to decrease or increase according to the cannula's wearing status, there is an effect that enables smooth respiratory treatment for the patient without medical staff having to check it individually.

[0023] Furthermore, according to an embodiment of the present invention, the effect of being able to undergo a process of diagnosing whether the supply flow rate of an automatically adjusted ventilator is appropriate for the patient by checking the patient's oxygen saturation (Saturation of partial pressure oxygen, SpO2) is appropriate for the patient is provided. Since a critical condition in which breathing becomes difficult due to hypoxia may occur if oxygen saturation drops, this enables measures to be taken, and in particular, it provides convenience for medical staff and has the effect of improving the accuracy of the patient's diagnosis. Brief explanation of the drawing

[0025] FIG. 1 is a diagram showing a control device for a ventilator according to the wearing state of a cannula according to an embodiment of the present invention. FIG. 2 is a diagram showing a structure in which a cannula and a ventilator are connected according to an embodiment of the present invention. Figure 3 is a graph showing the flow rate according to the patient's respiration according to an embodiment of the present invention. FIG. 4 is a flowchart illustrating a method for controlling a ventilator according to the wearing state of a cannula according to an embodiment of the present invention. Figure 5 is a flowchart illustrating an additional control method of Figure 4. FIG. 6 is a drawing showing an example of displaying the wearing state of a cannula according to an embodiment of the present invention through a display screen. Specific details for implementing the invention

[0026] In order to fully understand the present invention, the operational advantages of the present invention, and the objectives achieved by the embodiments of the present invention, reference must be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

[0027] The present invention will be described in detail below by explaining preferred embodiments of the invention with reference to the attached drawings. However, in describing the present invention, descriptions of already known functions or configurations may be omitted to clarify the gist of the invention.

[0028] FIG. 1 is a drawing showing a control device for a ventilator according to the wearing state of a cannula according to an embodiment of the present invention, and FIG. 2 is a drawing showing a structure in which a cannula and a ventilator are connected according to an embodiment of the present invention.

[0029] A device for implementing a method for controlling a respirator according to the wearing state of a cannula according to an embodiment of the present invention includes a respirator (100), a cannula (200), a flow measurement sensor (300), and a control device (400) as shown in FIG. 1.

[0030] The ventilator (100) emits a mixed gas at a concentration higher than the oxygen concentration in the atmosphere. The emitted mixed gas enters the patient's airway and assists the patient's breathing by ventilating the dead space where gas exchange does not occur.

[0031] This artificial respirator (100) is equipped with a humidifier to supply a heated and humidified mixed gas to the patient.

[0032] Additionally, as shown in FIG. 2, the ventilator (100) is connected to a nasal cannula (200) that is fixed by inserting thin tubes into both nostrils and hooking them over the ears, and through a supply hose, administers a heated and humidified mixed gas to the patient's nose.

[0033] The flow measurement sensor (300) measures the actual respiratory flow rate entering the patient's airway through the cannula (200) around the patient's nose. The measured respiratory flow rate can identify the pattern of respiratory flow rate according to the patient's breathing, including the inspiratory cycle and the exhalation cycle, as illustrated in FIG. 3.

[0034] The flow measurement sensor (300) can be mounted on the cannula (200) or on the supply hose connecting the cannula (200) and the ventilator (100).

[0035] The control device (400) analyzes the measurement signal received from the flow measurement sensor (300) to determine the wearing status of the cannula, and controls the supply flow rate of the ventilator to decrease or increase according to the determined wearing status of the cannula.

[0036] Additionally, the control device (400) controls the display screen to show the wearing status of the cannula determined through signal analysis, and can control the system to call a clinician if a certain amount of time has elapsed after controlling the supply flow rate of the ventilator to decrease or increase, or if an abnormality occurs in the patient's oxygen saturation.

[0037] The control device (400) may have its operation function programmed and be installed in the control algorithm of the ventilator (100), or it may be implemented in the form of a chip and mounted on the control unit of the ventilator (100). Additionally, the control device (400) may be implemented as a single device unit with a display screen independently of the ventilator (100).

[0038] Through this control device (400), the present invention measures the actual respiratory flow rate entering the patient's airway via the cannula (200) and compares the difference between the actual respiratory flow rate and the supply flow rate supplied by the ventilator (100) to indirectly determine the wearing status of the cannula. By automatically controlling the supply flow rate of the ventilator according to the wearing status of the cannula, the invention enables respiratory treatment of the patient without the clinician having to check the wearing status of the cannula one by one. Subsequently, the patient's oxygen saturation (Saturation of partial pressure oxygen, SpO2) can be checked to diagnose whether the automatically adjusted supply flow rate of the ventilator is appropriate for the patient. Since a critical condition in which breathing becomes difficult due to hypoxia may occur if oxygen saturation drops, the invention provides a method to take measures regarding this.

[0039] A specific control method thereof will be explained with reference to FIGS. 4 to 6.

[0040] FIG. 4 is a flowchart illustrating a method for controlling a ventilator according to the wearing state of a cannula according to an embodiment of the present invention.

[0041] Here, the control operation of the ventilator described is based on the general configuration of a ventilator that mixes oxygen and ambient air to generate a mixed gas and provides the generated mixed gas to flow into the patient's airway through a cannula. To facilitate understanding of the control method according to an embodiment of the present invention, it will be explained with reference to the components of FIG. 1.

[0042] First, in step S100, the flow measurement sensor (300) measures the actual respiratory flow rate entering the patient's airway through the cannula (200) near the patient's nose. Then, the measured signal is transmitted to the control device (400).

[0043] Next, the control device (400) checks whether the actual breathing flow rate measured by the flow measurement sensor (300) deviates from the reference value more than k times during a certain period (S110).

[0044] Here, the actual inflow rate can be checked in minutes at a minimum of one minute.

[0045] k times may vary depending on whether the patient is mild or severely ill with lung disease. For example, assuming that there are usually 16 breaths per minute in the case of a mild patient, 10 breaths (=k times) can be set as the value, and it can be set that flow rate adjustment is required if the number of times the respiratory flow rate during inspiration or expiration deviates from the standard value is 10 or more.

[0046] If the number of actual breathing flow rates that deviate from the standard value is less than k times, the control device (400) determines that the cannula wearing condition is good and controls it to display an alarm (S112, S114). For example, FIG. 6 shows an example in which the cannula wearing condition is displayed in a part area (①) of the display screen.

[0047] Conversely, if the actual breathing flow rate deviates from the standard value more than k times, the control device (400) determines whether the standard value has exceeded the standard upper limit (S120).

[0048] As a result of the judgment in step S120, if the number of times the actual breathing flow rate deviates from the standard value is k or more and exceeds the standard upper limit, that is, if the actual breathing flow rate exceeds the standard upper limit k or more, the control device (400) determines that the wearing state of the cannula is in an over-tight state and controls it to display this (S122).

[0049] Next, the control device (400) controls the supply flow rate of the ventilator to decrease according to the over-tight fit of the cannula (S124).

[0050] As a result of the judgment in the next step S120, if the actual breathing flow rate deviates from the standard value more than k times but the standard value does not exceed the upper limit of the standard, the control device (400) determines whether the lower limit of the standard has been exceeded (S130).

[0051] If the result of the judgment in step S130 is below the standard lower limit, return to the first step to measure the actual breathing flow rate.

[0052] As a result of the judgment in step S130, if the reference lower limit is exceeded, that is, if the number of actual breathing flow rates that deviate from the reference value is k or more and simultaneously exceeds the reference lower limit, the control device (400) determines that the wearing state of the cannula is a detached state and controls it to display this (S132, S134).

[0053] Next, the control device (400) controls the supply flow rate of the ventilator to increase according to the separation state of the cannula (S134).

[0054] Afterward, the control device (400) can adjust the supply flow rate of the ventilator according to the wearing status of the cannula, and then perform a process of diagnosing whether the adjusted supply flow rate is appropriate for the patient.

[0055] Referring to FIG. 5, a control device (400) measures the oxygen saturation of a patient and analyzes whether the oxygen saturation measurement value is within a normal range (e.g., 95% to 100%) (S200, S210).

[0056] If the oxygen saturation measurement is within the normal range, it is confirmed that the adjusted supply flow rate is being supplied normally to the patient, and the operation of supplying at the automatically adjusted supply flow rate is maintained (S200).

[0057] If the oxygen saturation measurement is outside the normal range, the control device (400) calls a clinician (medical staff) to prepare for the risk of respiratory distress caused by hypoxia (S230).

[0058] Through this diagnostic process, it is possible to verify whether the flow rate supplied to the patient is being delivered normally via a non-invasive method, and it provides the ability to apply the patient interface state to an optimal condition.

[0059] Here, oxygen saturation measurement can be performed by wearing a commonly used oxygen saturation meter on the patient's finger, transmitting the measured value to a control device, and reading the value.

[0060] The method of controlling a ventilator described above is merely one embodiment of the present invention, and as necessary, additional basic steps may be added and the order may be changed; therefore, the present invention is not limited to each step and the order described below.

[0061] FIG. 6 is a drawing showing an example of displaying the wearing state of a cannula according to an embodiment of the present invention through a display screen.

[0062] Display area ① indicates the degree of over-tightness or separation of the cannula, thereby ensuring optimal cannula fitting. Since the cannula's fit significantly affects PTIF measurements, this feature allows medical staff to easily check the fit without having to inspect each patient individually.

[0063] Display area ② displays the actual PTIF (Peak Tidal Inspiratory Flow, the patient's maximum tidal volume) as a number at regular intervals, allowing medical staff to more clearly understand the condition.

[0064] Display area ③ shows the actual respiratory flow rate entering the patient's airway as measured by the flow sensor, and visually indicates whether the PTIF exceeds the set flow rate.

[0065] Although the present invention has been described in detail through preferred embodiments, it is obvious to those skilled in the art that the present invention is not limited to the aforementioned preferred embodiments and can be modified and varied in various ways without departing from the spirit and scope of the invention. Accordingly, such modifications or variations should be deemed to fall within the scope of the claims of the present invention. Explanation of the symbols

[0066] 100: Ventilator 200: Cannula 300; flow measurement sensor 400: Control unit

Claims

Claim 1 A control method for an artificial respirator that mixes oxygen and ambient air to generate a mixed gas and controls the flow of the generated mixed gas into a patient's airway through a cannula, comprising: a step in which a flow measurement sensor measures the actual respiratory flow rate flowing into the patient's airway through the cannula; a step in which a control device checks the number of times the actual respiratory flow rate measured by the flow measurement sensor deviates from a reference value during a certain period of time; a step in which the control device determines whether the reference upper limit or reference lower limit has been exceeded if the number of times the actual respiratory flow rate deviates from the reference value is k or more in one minute; and a step in which the control device determines the wearing status of the cannula according to the determination result. The control device comprises a step of controlling the supply flow rate of the ventilator to decrease or increase according to the wearing state of the cannula, wherein in the step of determining the wearing state of the cannula, if the number of actual respiratory flow rates deviating from the reference value is k times or more per minute and exceeds the reference upper limit, the control device determines that the wearing state of the cannula is an over-tight seal and controls the device to display the determined wearing state of the cannula, and if the number of actual respiratory flow rates deviating from the reference value is k times or more per minute and exceeds the reference lower limit, the control device determines that the wearing state of the cannula is a detached state and controls the device to display the determined wearing state of the cannula, wherein the setting value of k times varies depending on whether the patient is mild or severely ill with severe lung disease, and the step of controlling the supply flow rate of the ventilator to decrease or increase controls the supply flow rate of the ventilator to decrease when the wearing state of the cannula is an over-tight seal, and when the wearing state of the cannula is a detached state, the ventilator's A method for controlling a ventilator according to the wearing state of a cannula, characterized by controlling to increase the supply flow rate. Claim 2 delete Claim 3 delete Claim 4 A method for controlling a ventilator according to the wearing state of a cannula, characterized by further including the step of, in claim 1, if the number of actual breathing flow rates deviating from the above standard value is less than k times, the control device determining that the wearing state of the cannula is good and controlling the device to display the determined wearing state of the cannula. Claim 5 A method for controlling a ventilator according to the wearing status of a cannula, characterized in that, in addition to the step of controlling the supply flow rate of the ventilator according to claim 1, the control device further comprises the step of measuring the oxygen saturation of a patient and analyzing whether the oxygen saturation measurement value is within a normal range; and the step of the control device calling a clinician if the oxygen saturation measurement value is outside the normal range.

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