Exhalation replacement point control method, system, and ventilator

Abstract

The application discloses an expiratory replacement point control method and system and a breathing machine. The method comprises the following steps: performing inspiration trigger detection on breathing waveform data in a unit breathing cycle, determining an inspiration trigger point, and constructing a breathing state conversion straight line according to the inspiration trigger point; when the breathing state conversion straight line and the breathing waveform data have an intersection point, determining a breathing flow sampling point set corresponding to the breathing waveform data; calculating the slope values of several breathing flow sampling points in the breathing flow sampling point set at a preset distance interval, and determining corresponding expiratory replacement points according to the slope values. The method can make the breathing state conversion straight line have an intersection point with the breathing waveform data when low ventilation and other respiratory events occur, ensure that the expiratory replacement operation of the breathing machine is consistent with the expiratory action of a user, realize man-machine synchronization, and has strong adaptability and improved user experience effect.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a method, system and ventilator for controlling the expiratory weaning point. Background Technology

[0002] In the medical field, non-invasive bilevel ventilators need to output lower pressure during the user's exhalation. The ventilator needs to accurately determine the expiratory phase of the user's spontaneous breathing during the transition from the high pressure output corresponding to the user's inhalation to the low pressure output corresponding to the user's exhalation. If the expiratory phase cannot be accurately identified during the user's spontaneous breathing, it may cause a conflict between the pressure adjustment of the ventilator and the pressure generated by the user's exhalation, thus causing discomfort to the user.

[0003] Currently, expiratory weaning point algorithms for ventilators typically include the following two methods. One is the flow threshold-based weaning method. This method detects whether the patient has entered the expiratory state by determining whether the respiratory flow is below a preset flow threshold. However, this method has two problems: firstly, when the preset threshold is set too high, it can lead to respiratory phase lag, resulting in poor respiratory follow-up and lower breathing comfort; secondly, when the preset threshold is set too low, it may cause difficulty in exhaling at the beginning of the expiratory phase, affecting the sensitivity of the expiratory trigger and resulting in poor reliability.

[0004] The second method is the flow waveform-based ventilator replacement method. This method delays the flow waveform curve of the current respiratory cycle by a certain time and then shifts it downwards. The first intersection of the downward-shifted curve with the flow waveform curve of the current respiratory cycle is the expiratory trigger point. However, this method requires a relatively regular and smooth flow waveform, and the sensitivity of the expiratory trigger is affected by the shape of the flow waveform, resulting in poor reliability. Moreover, the uncertainty of subsequent respiratory flow data leads to an uncertain intersection point between the changing waveform curve and the flow curve, which can cause the ventilator replacement to be too slow or too fast, and the ventilator replacement to be inconsistent with the user's expiratory actions. Summary of the Invention

[0005] One of the objectives of this invention is to provide an expiratory switch point control method to solve the technical problem that the prior art cannot adaptively adjust the expiratory switch point when processing respiratory flow data containing hypoventilation, resulting in inconsistency between the ventilator's expiratory switch point operation and the user's expiratory action, leading to a poor user experience.

[0006] One of the objectives of this invention is to provide an exhalation withdrawal point control system.

[0007] One of the objectives of this invention is to provide a ventilator.

[0008] To achieve one of the aforementioned objectives, this invention provides a method for controlling the expiratory switch point, comprising: performing inspiratory trigger detection on respiratory waveform data within a unit respiratory cycle, determining an inspiratory trigger point, and constructing a respiratory state transition line based on the inspiratory trigger point; wherein the respiratory state transition line characterizes the change in respiratory flow rate during the inspiratory phase within a unit respiratory cycle; when the respiratory state transition line intersects with the respiratory waveform data, determining a set of respiratory flow rate sampling points corresponding to the respiratory waveform data; calculating the slope values ​​of a plurality of respiratory flow rate sampling points in the set of respiratory flow rate sampling points at preset distance intervals, and determining the corresponding expiratory switch point based on the slope values.

[0009] As a further improvement of one embodiment of the present invention, the respiratory waveform data characterizes the change in respiratory flow data within a unit respiratory cycle.

[0010] As a further improvement of one embodiment of the present invention, the step of "performing inspiratory trigger detection on respiratory waveform data within a unit respiratory cycle and determining the inspiratory trigger point" specifically includes: acquiring respiratory airflow velocity signals within a unit respiratory cycle, filtering the respiratory airflow velocity signals to generate corresponding respiratory airflow waveform data; determining whether the respiratory airflow velocity corresponding to several respiratory flow sampling points on the respiratory airflow waveform data reaches a preset airflow velocity threshold; if so, determining the corresponding respiratory flow sampling point as an inspiratory trigger point.

[0011] As a further improvement of one embodiment of the present invention, the step of "performing inspiratory trigger detection on respiratory waveform data within a unit respiratory cycle and determining the inspiratory trigger point" specifically includes: acquiring respiratory airflow velocity signals within a unit respiratory cycle, filtering the respiratory airflow velocity signals to generate corresponding respiratory airflow waveform data; calculating and determining whether the respiratory volume data corresponding to several respiratory airflow sampling points on the respiratory airflow waveform data reaches a preset volume threshold; if so, determining the corresponding respiratory volume sampling point as an inspiratory trigger point.

[0012] As a further improvement of one embodiment of the present invention, the step of "constructing a respiratory state transition line based on the inhalation trigger point" specifically includes: obtaining the current respiratory cycle corresponding to the inhalation trigger point; determining the initial point position coordinates and slope value corresponding to the respiratory state transition line based on the current respiratory cycle; and constructing the respiratory state transition line based on the initial point position coordinates and the slope value.

[0013] As a further improvement of one embodiment of the present invention, the step of "determining the initial point position coordinates and slope value corresponding to the respiratory state transition line according to the current respiratory cycle" specifically includes: determining whether the current respiratory cycle is the first respiratory cycle; if not, obtaining and calculating the first sampling point and the second sampling point based on the inspiratory peak value of the previous respiratory cycle; wherein, the first sampling point and the second sampling point represent the start and end points of the inspiratory flow rate change phase in the previous respiratory cycle; calculating the slope value of the first sampling point and the second sampling point as the slope value of the current respiratory cycle; obtaining and using the abscissa corresponding to the inspiratory trigger point of the current respiratory cycle as the abscissa value of the initial point position coordinates, and using the ordinate value of the first sampling point as the ordinate value of the initial point position coordinates to generate the initial point position coordinates.

[0014] As a further improvement of one embodiment of the present invention, the step of "calculating the first sampling point and the second sampling point based on the inspiratory peak value of the previous respiratory cycle" specifically includes: calculating the ordinate value of the first sampling point and the ordinate value of the second sampling point based on the inspiratory peak value; wherein, the ordinate value of the first sampling point is equal to the product of the inspiratory peak value and a first preset threshold, and the ordinate value of the second sampling point is equal to the product of the inspiratory peak value and a second preset threshold; determining the first index position of the ordinate value of the first sampling point in the respiratory waveform data based on a sliding window of sampling point time, as the abscissa value of the first sampling point; determining the second index position of the ordinate value of the second sampling point in the respiratory waveform data based on a sliding window of sampling point time, as the abscissa value of the second sampling point; forming the first sampling point and the second sampling point based on the abscissa value and the ordinate value of the first sampling point, and the abscissa value and the ordinate value of the second sampling point, respectively.

[0015] As a further improvement of one embodiment of the present invention, the step of "determining the initial point position coordinates and slope value corresponding to the respiratory state transition line according to the current respiratory cycle" specifically includes: determining whether the current respiratory cycle is after the second respiratory cycle; if so, calculating the average value of the inspiratory peak value and slope value of several historical respiratory cycles before the current respiratory cycle by a preset number to obtain the average inspiratory peak value and average slope value; obtaining and using the abscissa value corresponding to the inspiratory trigger point of the current respiratory cycle as the abscissa value of the initial point position coordinate, and the average inspiratory peak value as the ordinate value of the initial point position coordinate to generate the initial point position coordinate; the step of "constructing the respiratory state transition line according to the initial point position coordinate and the slope value" specifically includes: constructing the respiratory state transition line corresponding to the current respiratory cycle according to the initial point position coordinate and the average slope value.

[0016] As a further improvement of one embodiment of the present invention, the step of "determining the set of respiratory flow sampling points corresponding to the respiratory signal data when the respiratory state transition line intersects with the respiratory waveform data" specifically includes: obtaining the respiratory signal after the intersection of the respiratory state transition line and the respiratory waveform data; performing an analog-to-digital conversion operation on the respiratory signal to obtain an analog-to-digital discrete digital signal corresponding to the respiratory signal; and determining the corresponding set of respiratory flow sampling points based on the analog-to-digital discrete digital signal using a sampling filtering algorithm.

[0017] As a further improvement of one embodiment of the present invention, the step of "calculating the slope values ​​of several respiratory flow sampling points in the respiratory flow sampling point set at preset distance intervals, and determining the corresponding expiratory switch point based on the slope values" specifically includes: calculating the slope of all two adjacent sampling points in the respiratory flow sampling point set at preset distance intervals to obtain several slope values; determining whether two adjacent slope values ​​have opposite signs; if so, taking the common respiratory flow sampling point corresponding to the two adjacent slope values ​​as a candidate point for the maximum value; and determining the expiratory switch point based on the candidate point for the maximum value and whether there is flow rebound in the respiratory waveform data within the current respiratory cycle.

[0018] As a further improvement of one embodiment of the present invention, the step of "determining whether there is flow rebound in the respiratory waveform data within the current respiratory cycle based on the maximum value candidate point, and determining the expiratory switch point based on the determination result" specifically includes: obtaining a set of candidate points to be replaced corresponding to the maximum value candidate point; wherein, the set of candidate points to be replaced represents the status of respiratory flow data points after the maximum value candidate point; calculating and determining whether the slope values ​​of all candidate points to be replaced are negative; if so, determining that there is no flow rebound in the respiratory waveform data within the current respiratory cycle, and determining the expiratory switch point based on the maximum value candidate point; if not, determining abnormal candidate points with positive slope values, updating the respiratory flow sampling point set based on the abnormal candidate points, and iteratively calculating a new maximum value candidate point based on the updated respiratory flow sampling point set until the expiratory switch point is determined.

[0019] As a further improvement of one embodiment of the present invention, the step of "obtaining a set of candidate points to be replaced corresponding to the candidate point of the maximum value" specifically includes: obtaining and selecting a number of respiratory flow sampling points after the first position of the candidate point of the maximum value in the set of respiratory flow sampling points to form the set of candidate points to be replaced; wherein, the set of candidate points to be replaced is a subset of the set of respiratory flow sampling points.

[0020] As a further improvement of one embodiment of the present invention, the step of "updating the respiratory flow sampling point set according to the abnormal candidate point" specifically includes: obtaining the second position of the abnormal candidate point in the respiratory flow sampling point set; deleting all set elements in the respiratory flow sampling point set from the initial position to the second position, thereby obtaining the updated respiratory flow sampling point set.

[0021] To achieve one of the above-mentioned objectives, one embodiment of the present invention provides an expiratory withdrawal point control system, comprising: a memory and a processor, wherein the memory has a computer program that can run on the processor, and the processor executes the program to implement the steps of any of the above-described expiratory withdrawal point control methods.

[0022] To achieve one of the above-mentioned objectives, one embodiment of the present invention provides a ventilator that, during the triggered exhalation process, executes the steps of any one of the above-described exhalation withdrawal point control methods.

[0023] Compared with the prior art, the embodiments of the present invention have at least one of the following beneficial effects:

[0024] This invention employs an expiratory switch point control method. Based on the inspiratory waveform data within a unit respiratory cycle, it adaptively constructs a respiratory state transition line, ensuring that the line intersects with the respiratory waveform data even during respiratory events such as hypoventilation, thus better adapting to the respiratory needs of different users. Simultaneously, it adaptively adjusts the expiratory switch point based on the respiratory flow data of the current respiratory cycle, ensuring that the ventilator's expiratory switch operation is consistent with the user's expiratory action, achieving human-machine synchronization, strong adaptability, and improved user experience. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the steps of the expiratory withdrawal point control method in one embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of some steps of the exhalation withdrawal point control method in the first embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram of the dynamic conversion line in the respiratory waveform data of the expiratory withdrawal point control method in one embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram of some steps in the first embodiment of the expiratory withdrawal point control method according to one embodiment of the present invention.

[0029] Figure 5 This is a detailed schematic diagram of step S13212 of the expiratory withdrawal point control method in one embodiment of the present invention.

[0030] Figure 6 This is a schematic diagram of some steps in a second embodiment of the expiratory withdrawal point control method according to one embodiment of the present invention.

[0031] Figure 7 This is a schematic diagram of some steps of the expiratory withdrawal point control method in the second embodiment of the present invention.

[0032] Figure 8 This is a schematic diagram of some steps of the exhalation withdrawal point control method in the third embodiment of the present invention.

[0033] Figure 9 This is a detailed schematic diagram of step S34 of the expiratory withdrawal point control method in one embodiment of the present invention.

[0034] Figure 10 This is a schematic diagram of the maximum value candidate point replacement in the exhalation withdrawal point control method according to an embodiment of the present invention.

[0035] Figure 11 This is a flowchart illustrating a preferred embodiment of the expiratory withdrawal point control method according to one aspect of the present invention. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the scope of protection of the present invention.

[0037] It should be noted that the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In the description of specific embodiments of the present invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] The expiratory withdrawal point is the critical moment when a ventilator switches from expiratory mode to inspiratory mode. Studying the expiratory withdrawal point helps to understand the respiratory physiology of users, optimize ventilator parameter configuration, and improve user comfort and treatment effectiveness. This is because studying the expiratory withdrawal point can not only solve current clinical problems, but also guide future research.

[0039] Based on this, the present invention provides a method for controlling the expiratory withdrawal point, such as... Figure 1 As shown, the expiratory withdrawal point control method specifically includes the following steps:

[0040] Step S1: Perform inspiratory trigger detection on the respiratory waveform data within a unit respiratory cycle, determine the inspiratory trigger point, and construct a respiratory state transition line based on the inspiratory trigger point;

[0041] Step S2: When the respiratory state transition line intersects with the respiratory waveform data, determine the set of respiratory flow sampling points corresponding to the respiratory waveform data;

[0042] Step S3: Calculate the slope value of several respiratory flow sampling points in the set of respiratory flow sampling points at preset distance intervals, and determine the corresponding expiratory switch point based on the slope value.

[0043] In this way, by constructing a respiratory state transition line, it can also intersect with the respiratory waveform data when respiratory events such as hypoventilation occur, which can better adapt to the respiratory needs of different users, ensure that the ventilator's expiratory switching operation is consistent with the user's expiratory action, and achieve human-machine synchronization.

[0044] The respiratory state transition line can characterize the change in respiratory flow during the inspiratory phase within a unit respiratory cycle; the respiratory waveform data can characterize the change in respiratory flow data within a unit respiratory cycle.

[0045] The inspiratory trigger point refers to the moment when the ventilator begins to deliver air, just as the user begins to inhale. It is the basis for the ventilator to determine whether the user needs to inhale at the end of expiration, and it is also an important moment for the ventilator to switch to inspiratory mode.

[0046] Specifically, in one embodiment, for the part in step S1 described as "performing inspiratory trigger detection on respiratory waveform data within a unit respiratory cycle to determine the inspiratory trigger point," the present invention provides detailed steps, which may specifically include:

[0047] Step S111: Collect the respiratory airflow velocity signal within a unit respiratory cycle, filter the respiratory airflow velocity signal, and generate corresponding respiratory airflow waveform data;

[0048] Step S112: Determine whether the respiratory airflow velocity corresponding to several respiratory flow sampling points on the respiratory airflow waveform data reaches a preset airflow velocity threshold.

[0049] If so, proceed to step S113 to determine the corresponding respiratory flow sampling point as the inspiratory trigger point.

[0050] Thus, by filtering the respiratory airflow velocity signal, noise and interference can be effectively reduced, generating more accurate respiratory airflow waveform data and improving the accuracy of inspiratory trigger point detection.

[0051] In another embodiment, for the part in step S1 described as "performing inspiratory trigger detection on respiratory waveform data within a unit respiratory cycle to determine the inspiratory trigger point", the present invention provides detailed steps, which may specifically include:

[0052] Step S121: Collect the respiratory airflow velocity signal within a unit respiratory cycle, filter the respiratory airflow velocity signal, and generate corresponding respiratory airflow waveform data;

[0053] Step S122: Calculate and determine whether the respiratory volume data corresponding to several respiratory airflow sampling points on the respiratory airflow waveform data reaches a preset volume threshold.

[0054] If so, proceed to step S123 to determine the corresponding respiratory volume sampling point as the inspiratory trigger point.

[0055] Thus, by filtering the respiratory volume signal, not only can noise and interference be effectively reduced, but it also helps to monitor the respiratory process more comprehensively, generate more accurate respiratory airflow waveform data, and improve the accuracy of inspiratory trigger point detection.

[0056] The respiratory airflow velocity refers to the speed at which breathing gas flows per unit time, and can be measured in liters per minute (L / min) or milliliters per second (ML / s). The respiratory volume refers to the total amount of gas inhaled or exhaled in a single breath, and can be measured in liters (L) or milliliters (ML). In ventilator applications, respiratory airflow velocity and respiratory volume are two important parameters that reflect the user's respiratory status, ventilation function, and respiratory needs.

[0057] Furthermore, the filtering operation can refer to filtering using a bandpass digital filter based on FIR (Finite Impulse Response). Since the frequency energy based on respiration is concentrated between 0.3Hz and 0.5Hz, a bandpass filter is used for processing, with its bandpass frequency set to 0.3Hz-0.5Hz, thus obtaining smooth and stable respiratory flow waveform data. Of course, this invention does not exclude other filtering algorithms.

[0058] It should be noted that different respiratory state transition lines can be constructed based on different inspiratory trigger points within different respiratory cycles. In other words, by collecting respiratory flow signals within different respiratory cycles, the inspiratory trigger point of each respiratory cycle can be determined, and the corresponding respiratory state transition line can be constructed.

[0059] Based on this, such as Figure 2 As shown, in the first embodiment, the expiratory withdrawal point control method may specifically include the following steps:

[0060] Step S131: Obtain the current respiratory cycle corresponding to the inhalation trigger point;

[0061] Step S132: Based on the current respiratory cycle, determine the initial point position coordinates and slope value corresponding to the respiratory state transition line;

[0062] Step S133: Construct the breathing state transition line based on the initial point position coordinates and the slope value.

[0063] Thus, by determining the corresponding initial point coordinates and slope value based on the inspiratory trigger point within each respiratory cycle, the consistency and accuracy of the respiratory state transition line can be improved.

[0064] Specifically, such as Figure 3 This diagram illustrates a preferred embodiment of the dynamic transition lines and respiratory waveform data. It assumes that a user's breathing process includes N respiratory cycles and N inspiratory trigger points. Based on these N inspiratory trigger points, N initial point coordinates and N slope values ​​can be determined. Based on these N initial point coordinates and N slope values, N respiratory state transition lines are constructed. This allows for dynamic monitoring and adjustment of the respiratory state. The respiratory state transition lines change dynamically within different respiratory cycles, enabling real-time adjustments based on the current respiratory state. This better adapts to changes in the user's breathing, improving the reliability and adaptability of the expiratory transition points.

[0065] Furthermore, such as Figure 4 As shown, in the first embodiment, for step S132, the present invention provides a refined step, specifically including:

[0066] Step S13211: Determine whether the current respiratory cycle is the first respiratory cycle;

[0067] If not, proceed to step S13212, obtain and calculate the first sampling point and the second sampling point based on the inspiratory peak value of the previous respiratory cycle;

[0068] Step S13213: Calculate the slope values ​​of the first sampling point and the second sampling point as the slope value of the current respiratory cycle;

[0069] Step S13214: Obtain the x-coordinate value of the initial point position coordinate, using the x-coordinate corresponding to the inspiratory trigger point of the current respiratory cycle as the x-coordinate value, and use the y-coordinate value of the first sampling point as the y-coordinate value of the initial point position coordinate, to generate the initial point position coordinate.

[0070] Thus, based on the continuity of the respiratory flow change trend, by utilizing the changes in inspiratory flow in the previous respiratory cycle, the slope value of the current respiratory cycle can be determined more accurately, the changes in inspiratory flow in the current respiratory cycle can be measured, and the expiratory switch point can be detected in a timely and accurate manner.

[0071] The first and second sampling points represent the start and end points of the inspiratory flow rate change phase within the previous respiratory cycle. In other words, the first and second sampling points reflect the changes in inspiratory flow rate within the previous respiratory cycle.

[0072] Specifically, such as Figure 5 As shown, in one embodiment, for step S13212, the present invention provides a refined step, specifically including:

[0073] Step S132121: Calculate the ordinate value of the first sampling point and the ordinate value of the second sampling point based on the inhalation peak value;

[0074] Step S132122: Based on the sliding window of the sampling point time, determine the first index position of the ordinate value of the first sampling point in the respiratory waveform data, and use it as the abscissa value of the first sampling point;

[0075] Step S132123: Based on the sliding window of the sampling point time, determine the second index position of the vertical coordinate value of the second sampling point in the respiratory waveform data, and use it as the horizontal coordinate value of the second sampling point;

[0076] Step S132124: The first sampling point and the second sampling point are formed based on the abscissa value and ordinate value of the first sampling point, and the abscissa value and ordinate value of the second sampling point, respectively.

[0077] Thus, by combining preset thresholds and sliding windows, respiratory flow data from the previous respiratory cycle can be dynamically obtained, offering high flexibility and adaptability. At the same time, the sliding window can simplify the calculation process of slope values ​​and initial point coordinates within the current respiratory cycle, improving efficiency.

[0078] Wherein, the ordinate value of the first sampling point is equal to the product of the inhalation peak value and the first preset threshold, and the ordinate value of the second sampling point is equal to the product of the inhalation peak value and the second preset threshold.

[0079] In the event of hypoventilation under normal breathing conditions, if the initial point coordinates of the dynamic transition line are set too large, the dynamic transition line may not intersect with the inspiratory flow data of hypoventilation. Preferably, the first preset threshold can be set to 0.7, and the second preset threshold can be set to 0.3. For ease of description, assuming the inspiratory peak value of the previous respiratory cycle is 'peak', the change in inspiratory flow data from 0.7*peak to 0.3*peak within the previous respiratory cycle is calculated. This range can reflect the rate of change of inspiratory flow intensity within the previous respiratory cycle. Of course, this invention does not exclude other preset thresholds and can be adjusted according to the actual respiratory events experienced by different users.

[0080] The first and second preset thresholds can be based on clinical criteria for hypoventilation events, defined as "a decrease of more than 30% in respiratory airflow intensity or amplitude during sleep compared to baseline levels." That is, 0.3*peak can represent 30% of the normal inspiratory flow rate in the previous respiratory cycle, and similarly, 0.7*peak can represent 70% of the normal inspiratory flow rate in the previous respiratory cycle.

[0081] Specifically, assuming the inspiratory flow rate data of 0.7*peak in the previous respiratory cycle corresponds to the inspiratory time point coordinate *in_index*, and the inspiratory flow rate data of 0.3*peak in the previous respiratory cycle corresponds to the inspiratory time point coordinate *end_index*, then the change in inspiratory flow rate data from in_index to end_index is (0.7*peak - 0.3*peak) / (in_index - end_index). That is, the position coordinates of the first sampling point are obtained as (in_index, 0.7*peak), and the position coordinates of the second sampling point are obtained as (end_index, 0.3*peak). Based on the position coordinates of the first and second sampling points, the slope of the respiratory state transition line in the current respiratory cycle is calculated to be 0.4*peak / (in_index - end_index).

[0082] Furthermore, the sliding window is based on a two-pointer concept, where a window is formed between the elements pointed to by the two pointers. In this invention, the sliding window for the sampling point time can be based on the time axis, selecting a continuous time period on the respiratory waveform data. The size of this time period is determined by the size of the sliding window; that is, the sliding window can be understood as a window that slides along the time axis. The x-coordinates of the first and second sampling points can respectively represent the time positions of the first and second sampling points in the respiratory waveform data.

[0083] To prevent situations where the dynamic conversion line and respiratory flow waveform data do not intersect due to respiratory events, in a preferred embodiment, historical respiratory waveform data from several historical respiratory cycles can also be considered.

[0084] Based on this, such as Figure 6 As shown, in the second embodiment, the present invention provides a detailed step for step S132, which specifically includes:

[0085] Step S13221: Determine whether the current respiratory cycle is after the second respiratory cycle;

[0086] If so, proceed to step S13222, calculate the average value of the inspiratory peak value and slope value of several historical respiratory cycles before the current respiratory cycle using a preset number, and obtain the average inspiratory peak value and average slope value.

[0087] Step S13223: Obtain the x-coordinate value of the initial point position coordinates, using the x-coordinate corresponding to the inhalation trigger point of the current breathing cycle as the x-coordinate value, and the average inhalation peak value as the y-coordinate value of the initial point position coordinates, to generate the initial point position coordinates.

[0088] Based on this, step S133 may specifically include:

[0089] Step S133': Based on the initial point position coordinates and the average slope value, construct a respiratory state transition line corresponding to the current respiratory cycle.

[0090] Thus, by calculating the average of several historical inspiratory peaks, outliers or random noise in a single respiratory cycle can be reduced, providing more accurate and reliable inspiratory peaks.

[0091] Preferably, the preset quantity is 3. That is, the slope values ​​of the three historical inspiratory peaks and the three dynamic transition lines of the three historical respiratory cycles preceding the current respiratory cycle are obtained; and the average value of the three historical inspiratory peaks and the slope values ​​of the three dynamic transition lines are calculated respectively. Of course, the present invention does not exclude other preset quantities, and no specific limitation is made here.

[0092] Combination Figure 1 and Figure 7 As shown, in the second embodiment, the expiratory withdrawal point control method may include the following steps:

[0093] Step S21: Obtain the respiratory signal after the intersection point of the respiratory state transition line and the respiratory waveform data;

[0094] Step S22: Perform an analog-to-digital conversion operation on the respiratory signal to obtain an analog-to-digital discrete digital signal corresponding to the respiratory signal;

[0095] Step S23: Based on the analog-to-digital discrete digital signal, the sampling and filtering algorithm determines the corresponding set of respiratory flow sampling points.

[0096] Thus, the key respiratory state transition points in the respiratory waveform data can be determined by the intersection points, laying the foundation for the accurate extraction of respiratory flow sampling points in the future.

[0097] The analog-to-digital conversion operation refers to converting the collected analog respiratory signal (i.e., the respiratory signal corresponding to step S21) into a digital signal (i.e., the analog-to-digital discrete digital signal corresponding to step S22), and performing a filtering operation on the converted digital signal based on a filtering algorithm to obtain a set of effective respiratory flow sampling points.

[0098] Combination Figure 1 and Figure 8 As shown, in the third embodiment, the expiratory withdrawal point control method may include the following steps:

[0099] Step S31: Calculate the slope of all two adjacent sampling points in the respiratory flow sampling point set at preset distance intervals to obtain several slope values;

[0100] Step S32: Determine whether two adjacent slope values ​​have opposite signs;

[0101] If so, proceed to step S33 and use the common respiratory flow sampling point corresponding to the two adjacent slope values ​​as the maximum value candidate point;

[0102] Step S34: Based on the candidate maximum value point, determine whether there is flow rebound in the respiratory waveform data within the current respiratory cycle, and determine the expiratory switch point.

[0103] Thus, by calculating the opposite signs of two adjacent slope values, it is helpful to find the point where the direction of change of inspiratory flow rate changes during the current respiratory cycle, thereby gaining a more accurate understanding of the current respiratory status and the adaptation of the ventilator.

[0104] The preset distance interval is preferably 1, that is, the slope value of each adjacent sampling point in the respiratory flow sampling point set is calculated. For example, suppose the respiratory flow sampling point set includes {P1, P2, P3, ..., P...} N}, then when the preset distance interval is 1, calculate (P1, P2), (P2, P3), ..., (P n-1 P nThe slope values ​​between (P1, P3), (P3, P5), ..., (P5) are calculated when the preset distance interval is 2. n-2 P n The slope values ​​between ) and ); and so on, which will not be discussed in detail here.

[0105] During inhalation, if the user's mask is not worn, slight air leakage may occur. In this case, the internal pressure of the ventilator will cause a brief increase in airflow, resulting in the flow rate slope value showing opposite signs during this phase. Furthermore, if the user coughs or snores, the inspiratory flow rate may suddenly decrease or increase, causing flow oscillations and also resulting in opposite slope values. Therefore, to further determine whether the opposite slope value is caused by occasional oscillations during inhalation or slight air leakage, it is necessary to determine whether there is a significant flow rebound after the current maximum candidate point.

[0106] Based on this, such as Figure 9 As shown, in one embodiment, step S34 may specifically include the following steps:

[0107] Step S341: Obtain the set of candidate points to be replaced corresponding to the candidate point of the maximum value;

[0108] Step S342: Calculate and determine whether the slope values ​​of all candidate points to be replaced are negative.

[0109] If so, proceed to step S343A, determine that there is no flow rebound in the respiratory waveform data within the current respiratory cycle, and determine the exhalation switch point based on the candidate point of the maximum value.

[0110] If not, proceed to step S343B, determine abnormal candidate points with positive slope values, update the respiratory flow sampling point set based on the abnormal candidate points, and iteratively calculate new maximum value candidate points based on the updated respiratory flow sampling point set until the exhalation switch point is determined.

[0111] In this way, by judging the rebound of respiratory flow within the current respiratory cycle, random interference factors can be eliminated, misjudgments can be avoided, and the accuracy and reliability of the expiratory switch point judgment can be improved.

[0112] The term "flow rebound" refers to the phenomenon where, during respiration, respiratory flow data decreases and then rebounds. This phenomenon can be caused by changes in the user's breathing state or improper adjustment of the ventilator's operating status or parameters.

[0113] Furthermore, the set of candidate points to be replaced can characterize the status of respiratory flow data points after the maximum candidate point; preferably, the set of candidate points to be replaced can be selected from 10 respiratory flow sampling points after the maximum candidate point. Of course, the present invention is not limited to 10 sampling points and can be freely selected according to actual conditions. The exhalation replacement point can be selected as the product of the respiratory flow value corresponding to the maximum candidate point and a preset threshold, and the preset threshold can be adjusted according to actual needs.

[0114] Based on this, step S341 can specifically include:

[0115] Step S341': Obtain and select several respiratory flow sampling points after the first position of the candidate point of the maximum value in the set of respiratory flow sampling points to form the set of candidate points to be replaced.

[0116] This allows for the determination of whether flow rebound occurs after the candidate maximum point, improving the reliability of the expiratory switch point determination. The set of candidate points to be replaced can be a subset of the set of respiratory flow sampling points.

[0117] Wherein, step S133' can be understood as a derivative step of step S133; step S341' can be understood as a derivative step of step S341; steps S13211 to S13214 can be set as a whole after steps S13221 to S13223, or as a whole before steps S13221 to S13223, or interspersed between any two steps S13221, S13222 and S13223. No specific limitation is imposed on this.

[0118] When an abnormal candidate point appears in the set of candidate points to be replaced, it indicates that the maximum value candidate point may not be the real expiratory switching point. At this time, it is necessary to continue to calculate whether the slope values ​​of several sampling points after the abnormal candidate point are all negative. In other words, it is necessary to determine whether the respiratory flow data after the maximum value candidate point decreases continuously for a period of time (preferably 50ms). Therefore, it is necessary to update the set of respiratory flow sampling points.

[0119] Based on this, in one embodiment, the present invention provides a refined step for step S343B:

[0120] Step S343B1: Obtain the second position of the abnormal candidate point in the respiratory flow sampling point set;

[0121] Step S343B2: Delete all set elements from the initial position to the second position in the respiratory flow sampling point set to obtain the updated respiratory flow sampling point set.

[0122] Thus, by updating the set of respiratory flow sampling points, changes in the user's respiratory status can be reflected in a timely manner, helping to improve the accuracy and efficiency of respiratory monitoring. The first and second positions can point to the same index location.

[0123] To better understand the update and iteration process, for example, Figure 10 This diagram illustrates the replacement of candidate points for the maximum value within the current respiratory cycle in a preferred embodiment. Assume the set of respiratory flow sampling points {P1, P2, P3, ..., P...} within the current respiratory cycle is... N If point P6 in the set is a candidate point for the maximum value, then the ten sampling points after P6 are selected to form a set, that is, the set of candidate points to be replaced is {P7, P8, ..., P...}. 16}; Calculate whether the slope value of each candidate point to be replaced in the set of candidate points to be replaced is negative. If the slope values ​​of these ten sampling points are all negative, then P6 is determined as the candidate point of the maximum value in the current respiratory cycle (i.e., the "inspiratory peak" point in the figure). Based on the candidate point of the maximum value, determine the expiratory switching point (preferably the product of the airflow rate corresponding to the "inspiratory peak" point and a preset threshold); if in P 10 If the slope of a point is positive, then P 10 Points are identified as abnormal candidate points; the original set of respiratory flow sampling points {P1, P2, P3, ..., P} is updated. N} is {P 10 P 11 P 12 , ..., P N}, and recalculate the updated set of respiratory flow sampling points {P}. 10 P 11 P 12 , ..., P N The candidate points for the new maximum value corresponding to} are determined until the exhalation switch point is determined.

[0124] The various embodiments, examples, or specific examples provided by this invention can be combined with each other to ultimately form multiple better embodiments.

[0125] Figure 11 A flowchart illustrating a preferred embodiment of the expiratory withdrawal point control method is shown below. Figure 11 The processing procedure of this preferred embodiment is summarized below.

[0126] Collect respiratory flow data within a unit respiratory cycle, and determine the inspiratory trigger point within that respiratory cycle based on the respiratory flow data.

[0127] A corresponding dynamic transition line is constructed based on the inspiratory trigger point; the intersection of the dynamic transition line and the respiratory flow waveform data is detected in real time, and the set of respiratory flow sampling points corresponding to the intersection point is obtained.

[0128] Calculate and determine whether the slope value of each respiratory flow sampling point in the set of respiratory flow sampling points has an opposite sign, and identify and mark the candidate point of the maximum value.

[0129] When the respiratory flow data after the candidate point of the maximum value decreases continuously (or the slope values ​​of several sampling points are all negative), the expiratory switch point of the current respiratory cycle can be determined based on the candidate point of the maximum value; when the respiratory flow data after the candidate point of the maximum value does not decrease continuously (or the slope values ​​of several sampling points are positive), the respiratory flow sampling point set is updated and the new candidate point of the maximum value of the updated respiratory flow sampling point set is calculated iteratively, and then it is continued to determine whether the respiratory flow data after the new candidate point of the maximum value decreases continuously until the expiratory switch point is determined.

[0130] The present invention also provides an expiratory withdrawal point control system, comprising: a memory and a processor, wherein the memory has a computer program that can run on the processor, and the processor executes the program to implement the above-described expiratory withdrawal point control method. 。

[0131] The present invention also provides a ventilator, wherein the ventilator executes the above-described expiratory withdrawal point control method during the triggered exhalation process.

[0132] In summary, the expiratory switch point control method provided by this invention adaptively constructs a respiratory state transition line by determining the inspiratory trigger point within a unit respiratory cycle. This line ensures that it intersects with the respiratory waveform data even in the event of respiratory events such as hypoventilation, thus better adapting to the respiratory needs of different users. Simultaneously, it adaptively adjusts the expiratory switch point based on the respiratory flow data of the current respiratory cycle, ensuring that the ventilator's expiratory switch operation is consistent with the user's expiratory action, achieving human-machine synchronization, strong adaptability, and improved user experience.

[0133] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0134] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling the expiratory withdrawal point, characterized in that, include: Inspiratory trigger detection is performed on the respiratory waveform data within a unit respiratory cycle to determine the inspiratory trigger point, and a respiratory state transition line is constructed based on the inspiratory trigger point; wherein, the respiratory state transition line characterizes the change in respiratory flow during the inspiratory phase within a unit respiratory cycle; When the respiratory state transition line intersects with the respiratory waveform data, a set of respiratory flow sampling points corresponding to the respiratory waveform data is determined; The slope values ​​of several respiratory flow sampling points in the set of respiratory flow sampling points are calculated at preset distance intervals, and the corresponding expiratory switch points are determined based on the slope values.

2. The expiratory withdrawal point control method according to claim 1, characterized in that, The respiratory waveform data represents the change in respiratory flow data within a unit respiratory cycle.

3. The expiratory withdrawal point control method according to claim 1, characterized in that, The phrase "performing inspiratory trigger detection on respiratory waveform data within a unit respiratory cycle to determine the inspiratory trigger point" specifically includes: Collect respiratory airflow velocity signals within a unit respiratory cycle, filter the respiratory airflow velocity signals, and generate corresponding respiratory airflow waveform data; Determine whether the respiratory airflow velocity corresponding to several respiratory flow sampling points on the respiratory airflow waveform data reaches a preset airflow velocity threshold. If so, the corresponding respiratory flow sampling point is determined to be the inspiratory trigger point.

4. The expiratory withdrawal point control method according to claim 1, characterized in that, The phrase "performing inspiratory trigger detection on respiratory waveform data within a unit respiratory cycle to determine the inspiratory trigger point" specifically includes: Collect respiratory airflow velocity signals within a unit respiratory cycle, filter the respiratory airflow velocity signals, and generate corresponding respiratory airflow waveform data; Calculate and determine whether the respiratory volume data corresponding to several respiratory airflow sampling points on the respiratory airflow waveform data reaches a preset volume threshold. If so, the corresponding respiratory volume sampling point is determined to be the inspiratory trigger point.

5. The expiratory withdrawal point control method according to claim 1, characterized in that, The phrase "constructing a respiratory state transition line based on the inhalation trigger point" specifically includes: Obtain the current respiratory cycle corresponding to the inspiratory trigger point; Based on the current respiratory cycle, determine the initial point coordinates and slope value corresponding to the respiratory state transition line; The breathing state transition line is constructed based on the initial point coordinates and the slope value.

6. The expiratory withdrawal point control method according to claim 5, characterized in that, The phrase "determining the initial point coordinates and slope value corresponding to the respiratory state transition line based on the current respiratory cycle" specifically includes: Determine whether the current respiratory cycle is the first respiratory cycle; If not, the first sampling point and the second sampling point are obtained and calculated based on the inspiratory peak value of the previous respiratory cycle; wherein the first sampling point and the second sampling point represent the start and end points of the inspiratory flow rate change phase in the previous respiratory cycle. Calculate the slope values ​​of the first sampling point and the second sampling point, and use them as the slope values ​​of the current respiratory cycle; The x-coordinate value of the inspiratory trigger point of the current respiratory cycle is obtained and used as the x-coordinate value of the initial point position coordinate, and the y-coordinate value of the first sampling point is used as the y-coordinate value of the initial point position coordinate to generate the initial point position coordinate.

7. The expiratory withdrawal point control method according to claim 6, characterized in that, The phrase "calculating the first sampling point and the second sampling point based on the inspiratory peak value of the previous respiratory cycle" specifically includes: Based on the inhalation peak value, the ordinate values ​​of the first sampling point and the second sampling point are calculated; wherein, the ordinate value of the first sampling point is equal to the product of the inhalation peak value and the first preset threshold, and the ordinate value of the second sampling point is equal to the product of the inhalation peak value and the second preset threshold. Based on a sliding window of sampling point time, the first index position of the ordinate value of the first sampling point in the respiratory waveform data is determined, and used as the abscissa value of the first sampling point. Based on a sliding window of sampling point time, the ordinate value of the second sampling point is determined to be the second index position in the respiratory waveform data, which is used as the abscissa value of the second sampling point; The first sampling point and the second sampling point are formed based on the x-coordinate value and y-coordinate value of the first sampling point, and the x-coordinate value and y-coordinate value of the second sampling point, respectively.

8. The expiratory withdrawal point control method according to claim 5, characterized in that, The phrase "determining the initial point coordinates and slope value corresponding to the respiratory state transition line based on the current respiratory cycle" specifically includes: Determine whether the current respiratory cycle is after the second respiratory cycle; If so, the average values ​​of the inspiratory peak and slope values ​​of several historical respiratory cycles before the current respiratory cycle are calculated using a preset number to obtain the average inspiratory peak and average slope values. The initial point position coordinates are generated by acquiring the x-coordinate value corresponding to the inspiratory trigger point of the current respiratory cycle as the x-coordinate value of the initial point position coordinates and using the average inspiratory peak value as the y-coordinate value of the initial point position coordinates. The phrase "constructing the respiratory state transition line based on the initial point coordinates and the slope value" specifically includes: Based on the initial point coordinates and the average slope value, a respiratory state transition line corresponding to the current respiratory cycle is constructed.

9. The expiratory withdrawal point control method according to claim 1, characterized in that, The phrase "when the respiratory state transition line intersects with the respiratory waveform data, determine the set of respiratory flow sampling points corresponding to the respiratory waveform data" specifically includes: The respiratory signal after the intersection point is obtained based on the intersection point of the respiratory state transition line and the respiratory waveform data; An analog-to-digital conversion operation is performed on the respiratory signal to obtain an analog-to-digital discrete digital signal corresponding to the respiratory signal; Based on the analog-to-digital discrete digital signal, a sampling filtering algorithm determines the corresponding set of respiratory flow sampling points.

10. The expiratory withdrawal point control method according to claim 1, characterized in that, The phrase "calculating the slope values ​​of several respiratory flow sampling points in the set of respiratory flow sampling points at preset distance intervals, and determining the corresponding expiratory switch points based on the slope values" specifically includes: The slope of all two adjacent sampling points in the respiratory flow sampling point set is calculated at preset distance intervals to obtain several slope values; Determine whether two adjacent slope values ​​have opposite signs; If so, the common respiratory flow sampling point corresponding to the two adjacent slope values ​​is taken as the candidate point of the maximum value; Based on the candidate maximum value, determine whether there is flow rebound in the respiratory waveform data within the current respiratory cycle, and determine the expiratory switch point.

11. The expiratory withdrawal point control method according to claim 10, characterized in that, The phrase "based on the candidate maximum point, determine whether there is flow rebound in the respiratory waveform data within the current respiratory cycle, and determine the expiratory switch point" specifically includes: Obtain a set of candidate points to be replaced corresponding to the candidate point of the maximum value; wherein, the set of candidate points to be replaced represents the status of respiratory flow data points after the candidate point of the maximum value; Calculate and determine whether the slope values ​​of all candidate points to be replaced are negative; If so, it is determined that there is no flow rebound in the respiratory waveform data within the current respiratory cycle, and the expiratory switching point is determined based on the candidate point of the maximum value. If not, then identify abnormal candidate points with positive slope values, update the respiratory flow sampling point set based on the abnormal candidate points, and iteratively calculate new maximum value candidate points based on the updated respiratory flow sampling point set until the exhalation switch point is determined.

12. The expiratory withdrawal point control method according to claim 11, characterized in that, The phrase "obtaining the set of candidate points to be replaced corresponding to the candidate point of the maximum value" specifically includes: Obtain and select several respiratory flow sampling points after the first position of the candidate point with the maximum value in the respiratory flow sampling point set to form the candidate point set to be replaced; wherein, the candidate point set to be replaced is a subset of the respiratory flow sampling point set.

13. The expiratory withdrawal point control method according to claim 11, characterized in that, The phrase "updating the respiratory flow sampling point set based on the abnormal candidate points" specifically includes: Obtain the second position of the abnormal candidate point in the set of respiratory flow sampling points; Delete all elements in the respiratory flow sampling point set from the initial position to the second position to obtain the updated respiratory flow sampling point set.

14. An expiratory withdrawal point control system, characterized in that, include: The device includes a memory and a processor, the memory having a computer program that can run on the processor, the processor executing the program to implement the steps of the expiratory withdrawal point control method according to any one of claims 1 to 13.

15. A ventilator, characterized in that, During the expiratory process, the ventilator executes the steps of the expiratory withdrawal point control method according to any one of claims 1 to 13.

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