Systems and methods for promoting secretion movement using mechanical ventilation

Abstract

A mucus removal system (100) and method automatically adjusts various ventilator parameters within a predetermined pressure range, including fall time, rise time, and inspiratory time, which are adjusted based on sensor input data and controlled to achieve a target flow bias difference or ratio.

Description

[Technical Field]

[0001] A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction of this patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or patent records, but otherwise reserves all copyright rights whatsoever.

[0002] The present invention relates to facilitating the movement of secretions produced in the pharyngeal and lung areas towards the pharyngeal and oral cavity areas of a person using a mechanical ventilator. [Background technology]

[0003] Secretions in the human airways can impair perfusion, preventing transmembrane humidification of gas and blocking normal airflow during breathing. Mucus secretions can thicken and thicken on the walls of small airways, leading to more serious health problems for affected individuals.

[0004] Patients with respiratory failure often suffer from respiratory infections and chronic hypersecretion or muscle weakness that leads to respiratory failure, which inhibits effective coughing and prevents mucus movement and clearance.

[0005] These patients who benefit from mechanical ventilator support may experience worsening mucus accumulation because positive pressure applied at the oral or tracheal site tends to push secretions in an inappropriate caudal (mis)direction for airway clearance.

[0006] Furthermore, it is recognized that the application of mechanical ventilation through an artificial airway inhibits the patient's ability to expel or swallow increased airway secretions.

[0007] It is now common for healthcare professionals to use certain adjunctive therapies to move secretions into the upper airways of mechanically ventilated patients, such as hyperinflation, PEEP-ZEEP maneuvers, chest compressions, or mechanically assisted evacuation (MI-E) devices.

[0008] These devices and movements create a high expiratory flow rate, detaching mucus from its cell walls and allowing it to move more easily from the lungs towards the main bronchi.

[0009] However, these techniques are often invasive and require the assistance of trained professionals to perform.

[0010] The present disclosure and the embodiments presented below seek to provide a solution that reduces human capital while utilizing current mechanical ventilator devices to provide a mucus removal system. These solutions, as well as other advantages, will be apparent to those skilled in the art from the written description provided. Summary of the Invention

[0011] In one embodiment, a method of using a ventilator to assist in mucus removal comprises the steps of: 1) inputting a target flow bias ratio into the ventilator, the target flow bias ratio being in the expiratory direction; 2) measuring a current flow bias ratio of the ventilator; 3) comparing the target flow bias ratio with the measured current flow bias ratio; and 4) modifying at least one of the operating parameters of the ventilator: a) rise time, b) fall time, or c) inspiratory time if the measured current flow bias ratio is not within a predetermined range of the target flow bias ratio.

[0012] The method may further include measuring the ventilator ramp-down time and determining whether the ventilator ramp-down time has reached a predetermined minimum value.

[0013] The method may further include generating a new fall time if the measured fall time does not reach a predetermined minimum value.

[0014] The method may further include generating a new rise time, a new fall time, and a new inspiratory time when the measured fall time reaches a predetermined minimum value.

[0015] The method, wherein the ventilator is configured to maintain a predetermined pressure therapy level.

[0016] A variation of the above method of using a ventilator, wherein the varying step comprises gradually increasing the measured flow bias ratio until a desired target flow bias ratio is achieved over a period of breaths, the period being at least 5 breaths, at least 10 breaths, at least 15 breaths, at least 20 breaths, or at least 25 breaths.

[0017] The fall time in the above method can be decreased to increase the measured flow bias ratio, or the fall time can be increased to decrease the measured flow bias ratio.

[0018] In yet another embodiment, a mucus removal assistance system includes a ventilator system configured to provide positive pressure air to a user, one or more sensors configured to detect a flow rate associated with the ventilator, and a controller configured to modify one or more output parameters associated with the ventilator, the controller having a programmable logic circuit or memory and a processing unit configured to perform the following steps: 1) receiving a target flow bias ratio input; 2) receiving a measured flow rate from the one or more sensors; 3) determining a flow bias ratio from the measured flow rate; 4) comparing the measured flow bias ratio to the target bias ratio; 5) determining whether the measured flow bias ratio needs to be increased or decreased; and 6) modifying at least one of a fall time parameter, a rise time parameter, and an inspiratory time parameter based on the determination to increase or decrease the measured flow bias ratio.

[0019] The mucus removal assist system can be designed such that the fall time and rise time parameters are based on the rate at which the ventilator is pressurized or depressurized, respectively, and the controller can be configured to vary the pressurization and depressurization rates of the ventilator.

[0020] The mucus removal assist system may be designed such that the controller is further configured to determine whether the ventilator ramp-down time has reached a predetermined minimum value.

[0021] The mucus removal assistance system can be designed such that if the measured fall time does not reach the predetermined minimum value, the control device can generate a new fall time.

[0022] The mucus removal assist system can be designed such that the control device is further configured to perform the step of generating a new rise time, a new fall time, and a new inspiratory time when the measured fall time reaches the predetermined minimum value.

[0023] These and other embodiments will become apparent to those of ordinary skill in the art upon review of the remainder of this application. [Brief explanation of the drawings]

[0024] [Figure 1] Figure 1 shows a ventilator system. [Figure 2] FIG. 2 is a diagram illustrating the lungs and the flow of inhaled and exhaled air into and out of the lungs. [Figure 3] FIG. 3 is a schematic diagram of a mucus removal system. [Figure 4] 4A-B illustrate various methodologies for setting a target flow bias, measuring the current flow bias, and determining changes. [Figure 5] FIG. 5 shows a schematic diagram that also includes utilizing bias error as part of the decision to update ventilator operating parameters. [Figure 6] Figures 6A.1-D.5 show various graphs that provide examples of modifying ventilator operating parameters in various ways based on measured flow bias and other measured parameters. DETAILED DESCRIPTION OF THE INVENTION

[0025] Definitions useful in this application include the following:

[0026] Inspiratory flow refers to the flow of air entering and moving toward the lungs, and expiratory flow refers to the flow of air leaving the lungs toward the glottis.

[0027] Rise time is the rate at which pressure rises to a defined or determined pressure level, which typically occurs during inspiration. The rise time of pressure affects flow, particularly inspiratory flow, and more particularly peak inspiratory flow.

[0028] Fall time is the rate at which pressure falls to a determined pressure level, which typically occurs during expiration. The fall time of pressure affects flow, particularly expiratory flow, and more particularly expiratory peak flow.

[0029] Inspiratory time is the length of time that the ventilator delivers inspiratory pressure.

[0030] PEEP stands for positive end-expiratory pressure.

[0031] ZEEP is zero end-expiratory pressure.

[0032] Lung hyperinflation is when the lungs become too full.

[0033] Prescribed pressure or pressure dose is the pressure to which the ventilator will raise the pressure during mechanical ventilation and is usually prescribed by a healthcare provider. Pressure is usually measured in cmH2O or centimeters of water. Prescribed pressures typically range from 5 to 25 cmH2O and generally do not exceed 30 cmH2O.

[0034] The flow bias ratio is the absolute value of the PEF / PIF ratio.

[0035] Flow bias is the difference between peak expiratory flow (PEF) and peak inspiratory flow (PIF). For example, if PIF = 30 L / min and PEF = -35 L / min, the flow bias is 5 L / min.

[0036] Measurement flow bias refers to the measured or observed flow bias.

[0037] Measured Flow Bias Ratio Refers to the measured or observed flow bias ratio.

[0038] The term significant, as used throughout this application, refers to a statistical or mathematical deviation from the mean or expected mean, whether a significant decrease, significant improvement, significant deterioration, or other variation. This statistical deviation generally means at least one standard deviation or more; anything less than one standard deviation is not considered significant. Because using standard deviation is not always robust, other forms of deviation, such as median absolute deviation, can also be used. In summary, those skilled in the art of statistics will understand when a value has a mathematical or statistical variation that is "significant."

[0039] Figure 1 shows a basic ventilator system 10 that provides pressurized air to a user / patient 16 through tubing 12 to an airway adapter 14, such as a mask. In some cases, such as when the tubing is delivered directly to the trachea, such as in a tracheotomy, a mask may not be used.

[0040] 2 shows lungs 20 including a trachea 22 and lung bronchi 24. An inspiratory flow path 26 enters the trachea 22 and flows into the bronchi 24, and an expiratory flow path 28 enters and leaves the lungs 20 and the bronchi 24 and enters the trachea 22.

[0041] It should be understood that the amount of air that the user / patient inhales or breathes in should generally be equal to the amount of air that the user / patient exhales or breathes out. If this is not the case, the user / patient will have problems. Therefore, if the user / patient is using a ventilator, it is designed to ensure that the amount of air entering the lungs is equal to the amount of air leaving the lungs.

[0042] It is well known that in a secondary pneumatic system (a secondary pneumatic system is a system in which the dynamics within the system are determined only by pressure, flow, and the first derivative of pressure and flow), peak flow is determined by the rate of change of the driving pressure. The rate of change of the driving pressure is programmed by the "rise time" and "decline rate" settings in the mechanical ventilator settings. The "rise time" determines the inflation rate at the start of inspiration, and therefore affects the peak inspiratory flow. The "decline time" determines the decompression rate at the start of expiration, and therefore affects the peak expiratory flow.

[0043] Using the leaf blower analogy, a higher flow rate from a more powerful leaf blower is more likely to lift leaves off the ground and collect them for disposal. In the present invention, a high peak expiratory flow rate induced by rapid airway decompression is more likely to lift secretions from the airway walls and collect them near the glottis where they can be removed.

[0044] In mechanical ventilation, during assisted inspiration, the leaf blower may be misdirected as air is forced into the lungs, making it difficult for the patient to manage the upward movement of secretions by natural means or coughing. Thus, by this analogy, it can be seen that controlling or varying the "rise time" and "fall time" can have the overall effect of correcting the leaf blower's direction, as determined by the target bias flow ratio or difference.

[0045] As mentioned in the Background section, previous maneuvers, such as expiratory chest compressions (ERCC) and monitored maneuvers, such as hyperinflation, which may involve temporarily setting the peak inspiratory pressure to 40 cmH2O, are designed to be used only under monitored circumstances. This is because both of these maneuvers require additional equipment and / or supervision by a medical professional. In contrast, the methods and systems discussed herein can be performed within predetermined pressure limits intended for use by the user / patient over a longer period of time, helping to eliminate some of the additional medical professional supervision and / or implementation. For example, hyperinflation using a pressure of 40 cmH2O is well outside the normal prescribed range of 5-25 cmH2O for consistent ventilator use. Therefore, by automatically modifying the rise time, fall time, and inspiratory time parameters without changing the predetermined pressure, the methods and systems described herein can achieve the desired flow bias differential or ratio over a longer period of time, avoiding additional time or technique required by a medical professional. In some cases, the consistency of the methods and systems described herein may be more effective at removing mucus from users / patients, may be less costly, may require less labor intensive medical professionals, and may be adapted to utilize existing ventilators on the market.

[0046] FIG. 3 illustrates a schematic of a mucus removal system 100, including a ventilator system 10, that includes a processing unit 30 configured to receive input parameters, such as a target flow bias parameter, via a user / patient input interface 36, implement algorithms, protocols, and direct and analyze sensor data captured by sensors 34, retrieve the data and place it in memory 32, and direct communication over a network 40 to a remote server / cloud 50 that also includes processing circuitry and storage. Directed communication 42 can occur to and from a communications network, which in turn can direct communication 44 to and from the remote server / cloud 50. Cloud computing is generally understood in the art to mean the delivery of computing services, including servers, storage, databases, networking, software, analytics, and intelligence, over the Internet (the "cloud") to provide faster innovation, flexible resources, and economies of scale.

[0047] 4A-B illustrate various methods for setting a target flow bias, measuring the current flow bias, and determining (and implementing) the necessary changes until the measured flow bias (ratio or difference) falls within a predetermined range of the target flow bias (ratio or difference).

[0048] Referring to flowchart 400A of FIG. 4A, a user, such as a medical professional, sets a target flow bias or differential that the ventilator should operate to achieve. An example target range for the flow bias ratio may be 1.1. Other target flow bias ratios are 1.05, 1.06, 1.07, 1.08, 1.09, 1.11, 1.12, 1.13, 1.14, and 1.15. The target flow differential is at least 17 L / min, with alternative differentials being at least 16 L / min, at least 18 L / min, and at least 19 L / min. Once the target flow bias is entered, the next step is to begin measuring flow to determine the current flow bias. This can be done using one or more sensors associated with the ventilator. Flow and pressure are common measurements that most ventilators are configured to measure. Measuring pressure is often used to estimate leaks in a given ventilator system, thereby providing a more accurate estimate of the actual flow being measured.

[0049] These measurements can be used to determine the PEF and PIF, which can then be used to determine the PEF / PIF ratio or the PEF-PIF difference. Once the measured flow bias is determined, the next step is to determine whether it is within a predetermined range of the target flow bias. This predetermined range may be an actual numerical value, or it may be determined to be statistically significant based on the input target flow bias value. For example, if the target flow bias ratio is 1.1 and the measured flow bias ratio is 1.0998, this is likely within the predetermined range, and therefore, as indicated by the determining step, there is no need to change the current operating parameters of the ventilator. Therefore, measurements continue until the difference between the target flow bias and the measured flow bias is outside the predetermined range.

[0050] If the measured value is determined to be outside the predetermined range, the next step is to modify at least one of the following parameters depending on whether the ratio or difference is higher or lower than the target value: 1) rise time, 2) fall time, or 3) inspiratory time. In some cases, it may be necessary to adjust one or more of the above parameters. Once the parameters are adjusted, the next step is to allow one or more cycles to elapse and begin measuring flow bias using the updated parameters. These steps are repeated until optimal parameters are obtained. It should be noted that a user's / patient's breathing may vary throughout the day or night, as different stages of sleep or wakefulness may alter breathing patterns. Therefore, the parameters may be automatically updated throughout the day based on the user's / patient's biological cycle.

[0051] Referring to flowchart 400B of FIG. 4B, a user, such as a medical professional, resets the target flow bias ratio or target bias flow difference that the ventilator should achieve. The first few steps are similar to flowchart 400A, except that if the measured target flow bias ratio is determined to be outside a predetermined range, an intermediate step is performed to determine whether the current fall time is at a minimum threshold. If not, the method recommends a new rise time update. If so, the method can recommend new rise, fall, and inspiratory times. After each recommendation, the method can include implementing the new recommendations and initiating a new cycle of measuring and comparing the flow bias to the target flow bias.

[0052] FIG. 5 is a schematic diagram that also includes utilizing bias error as part of the decision to update the ventilator's operating parameters. Here, the target flow bias is set to a ratio of 1.1 and compared to the measured flow bias ratio. Kp represents a proportional gain controller, which serves to change the rate at which the ventilator pressurizes and depressurizes. As discussed above, the rate at which the ventilator pressurizes affects the flow rate during the fall or rise time, ultimately determining the PEF and PIF, which are used to calculate the flow bias ratio. If the flow bias ratio is properly optimized, mucus can be removed from the lungs, trachea, and other areas without the need for, or at least reducing the frequency of, additional therapy to manage mucus accumulation. Bias error can be determined using several of the equations shown. Similar to flowchart 400B, the current fall time can be measured and used to determine whether it is at a minimum threshold. If not, a new fall time is recommended, and if so, the bias error equation can be used to initiate a new rise time, new fall time, new inspiratory time, and / or new pressure support.

[0053] To further illustrate the effectiveness of the above-described systems and methods, Figures 6A.1-D.5 are provided to illustrate various graphs showing examples of varying the operating parameters of the ventilator based on the measured flow bias and other measured parameters.

[0054] For example, in Figures 6A.1-A.5, the initial flow bias ratio is measured at 1.0199, and the desired target flow bias ratio is 1.1. As a result, the controller decreases the ventilator's operating parameter, the fall time, in order to increase the measured flow bias ratio. Figure 6A.1 readily shows how the fall time decreases from an initial 0.1 second to 0.07 seconds after approximately 10 breaths in a cycle. The effect of this change is illustrated by comparing the measured starting flow waveform (Figure 6A.2) and starting pressure waveform (Figure 6A.3) graphs on the left with the final flow waveform (Figure 6A.4) and final pressure waveform (Figure 6A.5) graphs on the right. The resulting end ratio, or new measured ratio, is 1.0996, as shown in Figure 6A.4.

[0055] In another example, in Figures 6B.1-B.5, the initial measured flow bias ratio is 1.2847. Because the desired target flow bias ratio is 1.1, the controller increases the fall time to lower the initial measured flow bias ratio. In Figure 6B.1, it is easy to see that the fall time increases from an initial 0.1 second to 0.13 seconds after approximately 10 breaths, and then to 0.14 seconds after approximately 25 breaths have occurred in the cycle. The effect of this change is again shown by comparing the measured starting flow waveform (Figure 6B.2) and starting pressure waveform (Figure 6B.3) graphs on the left with the final flow waveform (Figure 6B.4) and final pressure waveform (Figure 6B.5) graphs on the right. The resulting end ratio, or new measured ratio, is 1.1006, as shown in Figure 6B.4.

[0056] In yet another example, in Figures 6C.1-C.5, the initial measured flow bias is approximately 1.2. Because the desired target flow bias ratio is 1.1, the controller increases the fall time to lower the initial measured flow bias ratio. In Figure 6C.1, it is easy to see that the fall time increases from an initial 0.1 second to approximately 0.12 seconds after approximately 10 breaths, and then to 0.13 seconds after approximately 25 breaths have occurred in the cycle. The effect of this change is again shown by comparing the measured starting flow (Figure 6C.2) and pressure (Figure 6C.3) waveforms on the left with the final flow (Figure 6C.4) and pressure (Figure 6C.5) waveforms on the right. This results in an ending or new measured ratio of approximately 1.1, as shown in Figure 6C.4.

[0057] In yet another example, in Figures 6D.1-D.5, the initial measured flow bias ratio is approximately 0.6. Because the desired target flow bias ratio is 1.1, the controller minimizes fall time and increases rise time to increase the measured flow bias ratio. In Figure 6D.1, it is easy to see that the fall time decreases from the initial 0.1 seconds to the predetermined minimum fall time after approximately 10 breaths, and the rise time, pressure support (PS), and inspiratory time (Tinsp) are subsequently adjusted according to the algorithm of Figure 5. The rise time increases from 0.2 seconds to 1.6 seconds between breaths 10 and 15 of the cycle. Pressure support and inspiratory time increase to maintain constant peak pressure, according to the relationship of Figure 5. The effect of this change is again illustrated by comparing the measured graphs of the beginning flow waveform (Figure 6D.2) and beginning pressure waveform (Figure 6D.3) on the left with the measured graphs of the ending flow waveform (Figure 6D.4) and ending pressure waveform (Figure 6D.5) on the right. This results in an ending ratio or new measured ratio r of 1.1, as shown in Figure 6D.4, ​​which can be seen because the maximum pressure delivered is the same for the starting and ending waveform graphs.

[0058] As described above, by noting where the measured flow bias initially lies relative to the target flow bias, the methods and systems described herein can adjust one or more ventilator operating parameters within a given pressure to achieve operation near the target flow bias ratio or difference. When the flow bias ratio or difference is set appropriately, it helps to move mucus away from the lungs and trachea. These methods and systems can be implemented to automatically adjust the ventilator operating parameters as needed, thereby applying a constant and consistent flow bias ratio to the user and consistently moving mucus away from the lungs and trachea.

[0059] While the principles of the present invention have been described herein, it is to be understood by those skilled in the art that this description is made by way of example only and is not intended to limit the scope of the invention. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. Modifications and substitutions by those skilled in the art are deemed to be within the scope of the present invention.

Claims

1. A ventilator system, A non-invasive positive pressure air system (10) is configured to supply positive pressure air to a user wearing a mask through a tube (12), and the non-invasive positive pressure air system (10) is configured to supply positive pressure air to a user wearing a mask. One or more sensors (34) configured to measure expiratory flow rate and inspiratory flow rate, and the one or more sensors (34), A control device configured to automatically control the flow bias ratio to assist in the removal of mucus, and It has, The control device has a programmable logic circuit or algorithm, a memory (32), and a processing unit (30), The processing unit (30) is A step of receiving a target flow bias ratio input to the control device via a user / patient input interface (36), wherein the target flow bias ratio is biased towards the expiratory direction, and the receiving step, The process of receiving the measured flow rate in the exhalation direction and the measured flow rate in the inhalation direction from the aforementioned one or more sensors, A step of determining the measured flow bias ratio from the measured expiratory flow rate and the measured inspiratory flow rate, A step of comparing the measured flow bias ratio with the target bias ratio, A step of determining whether the measured flow bias ratio needs to be adjusted, A step of automatically controlling the air system, wherein if the measured flow bias ratio is less than the target flow bias ratio, the flow bias ratio is increased by a combination of decreasing the descent time, increasing the rise time, and increasing the intake time, or if the measured flow bias ratio exceeds the target flow bias ratio, the flow bias ratio is decreased by a combination of increasing the descent time, decreasing the rise time, and decreasing the intake time, and the control step is It is configured to perform the following: A ventilator system.

2. The system according to claim 1, wherein the parameters for the descent time and rise time are based on the period during which each is pressurized or depressurized.

3. In the system according to claim 1, the control device further comprises: A system configured to determine whether the descent time of the ventilator has reached a predetermined minimum value.

4. The system according to claim 3, wherein the control device can generate a new descent time if the measured descent time has not reached the predetermined minimum value.

5. In the system according to claim 3, the control device further comprises: A system configured to perform the steps of generating a new rise time, a new descent time, and a new intake time when the measured descent time reaches the predetermined minimum value.

6. In the system according to claim 3, the control device further comprises: A system configured to gradually increase the measured flow bias ratio over the respiratory cycle until a desired target flow bias ratio is reached.

7. The system according to claim 6, wherein the respiratory cycle is at least 5 times, at least 10 times, at least 15 times, at least 20 times, or at least 25 times.

8. In the system according to claim 1, the control device further comprises: A system configured to shorten the descent time in order to increase the measured flow bias ratio.

9. In the system according to claim 1, the control device further comprises: A system configured to increase the descent time in such a way as to decrease the measured flow bias ratio.

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