WO2012089090A1

WO2012089090A1 - Method and device for controlling inspiration trigger and breathing machine

Info

Publication number: WO2012089090A1
Application number: PCT/CN2011/084694
Authority: WO
Inventors: 刘庆平
Original assignee: 北京谊安医疗系统股份有限公司
Priority date: 2010-12-31
Filing date: 2011-12-26
Publication date: 2012-07-05
Also published as: EA023035B1; CN102266614A; BR112012032965A2; EA201270805A1

Abstract

A method and a device for controlling an inspiration trigger and a breathing machine. The control method comprises: detecting a parameter value in an air passage in an expiration process (S102); judging whether the parameter value reaches an inspiration trigger value changing with the autonomous expiration cycle of a patient (S104); and determining, according to a judgment result, whether to switch from expiration to inspiration (S106). Through the control method and device, the inspiration trigger can be conveniently controlled, thereby reducing ineffective inspiration work of the patient without incurring a false trigger.

Description

Description Control method and device for inhalation trigger, ventilator

TECHNICAL FIELD The present invention relates to the field of ventilators, and in particular to a method and device for controlling an inhalation trigger, and a ventilator. Background technique

In some ventilator ventilation modes, such as pressure support mode (PSV), in order to achieve ventilator aspiration and patient autonomous inspiratory synchronization, a pressure trigger or flow trigger mechanism is generally used to determine when to exhale to inhale. Conversion. Whether it is pressure trigger or flow trigger, the expiratory to inspiratory transition is performed as long as the monitored airway pressure or flow reaches a set threshold. This threshold is called trigger sensitivity.

In general, flow triggering is less laborious than pressure triggering (reducing the patient's inspiratory effort), especially in the case of auto-peep and ventilation for children and in non-invasive ventilation. The flow trigger sensitivity is generally set by manual input. The principle of setting is: Set a small trigger sensitivity as much as possible to avoid false triggering.

In the process of ventilation, false triggering occurs from time to time. The factors that cause false triggering are noise of measuring flow, leakage, flow fluctuation caused by accumulated water, patient's own cardiogenic vibration, and patient's movement. In order to avoid false triggering, it is often necessary to set a higher trigger sensitivity, so the setting of the trigger sensitivity is a compromised sensitivity setting, because such a setting will increase the patient's inspiratory triggering work, and may even cause ineffective inspiratory work.

Therefore, it is necessary to develop a trigger mechanism that has the best of both worlds, and does not increase the patient's inspiratory triggering power while reducing false triggering. The Respironics Esprit (V200) ventilator uses a multi-information automatic trigger mechanism: initiates multiple trigger mechanisms at different times of exhalation, ie as the exhalation progresses, Start more triggering criteria, and trigger when any one of the triggering criteria is met, so the sensitivity of the trigger is getting higher and higher.

Although the sensitivity is triggered by this pre-expiratory restriction, the method of increasing the trigger sensitivity at the end of expiration can reduce and falsely trigger without increasing the patient's inspiratory trigger work, but the solution in the Respironics Esprit (V200) ventilator is There are a lot of inconveniences in the implementation: (1) using a lot of triggering criteria to trigger the judgment, on the one hand, increasing the amount of calculation; (2) on the other hand, a fixed threshold is automatically set for each trigger criterion, and these thresholds are Reasonability is difficult to guarantee; (3) In order to judge the period of exhalation, there are some complicated judgment criteria set by the human body.

In view of the contradictory problem of the sensitivity setting of the inhalation trigger in the related art, an effective solution has not yet been proposed.

Summary of the invention

The present invention has been made in view of the contradiction of the inhalation trigger sensitivity setting in the related art. Therefore, it is a primary object of the present invention to provide a method and apparatus for controlling an inhalation trigger and a ventilator to solve the above problems.

In order to achieve the above object, according to an aspect of the present invention, an inhalation trigger control method is provided. The control method includes: monitoring a parameter value in the airway during exhalation; determining whether the parameter value reaches an inhalation trigger value that changes according to a patient's voluntary exhalation cycle; determining whether to exhale according to the result of the judging Conversion to inhalation.

Further, the parameter values in the airway include: a pressure in the air passage; or a flow rate in the air passage.

Further, monitoring the parameter values in the airway includes: monitoring a change amount of the parameter value in the air channel, and determining whether the parameter value reaches the trigger value comprises: determining whether the change amount of the parameter value in the air channel reaches the trigger sensitivity. Further, determining whether to perform the conversion of exhalation to inhalation according to the result of the determining comprises: determining a timing of transition from exhalation to inhalation by using a pressure trigger or a flow trigger mechanism.

Further, before determining whether the parameter value reaches the trigger value, the method further includes: receiving parameter information input by the user; and obtaining the trigger value according to the parameter information.

In order to achieve the above object, according to another aspect of the present invention, an inhalation trigger control device is provided. The control device comprises: a monitoring module, configured to monitor a parameter value in the airway during the exhalation process; a judging module, configured to determine whether the parameter value reaches a trigger value; and a determining module, configured to be based on the judging Determine whether to switch from exhalation to inhalation.

Further, the inhalation trigger control device further includes: a receiving module, configured to receive parameter information input by the user; and an acquiring module, configured to obtain the trigger value according to the parameter information.

In order to achieve the above object, according to another aspect of the present invention, a ventilator is provided. Wherein, the ventilator comprises the inhalation trigger control device described above.

Through the invention, the sputum is used in the exhalation process to monitor the parameter value in the airway; determining whether the parameter value reaches the inhalation trigger value that varies with the patient's expiration period; determining whether to exhale according to the result of the judgment The method of switching to inhalation solves the contradiction problem of the inhalation trigger sensitivity setting in the related art, thereby achieving the purpose of effectively controlling the inhalation trigger.

DRAWINGS

The drawings described herein are provided to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

1 is a flow chart of a method of inhalation trigger control according to an embodiment of the present invention; 2 is a schematic diagram of traffic triggering in a PSV mode according to an embodiment of the present invention; FIG. 3 is a schematic diagram of a waveform of a false trigger according to an embodiment of the present invention;

4 is a schematic diagram of trigger sensitivity based on patient autonomous exhalation time learning, in accordance with an embodiment of the present invention;

Figure 5 is a flow chart of a preferred embodiment of the inhalation trigger control method according to the present invention; and Figure 6 is a schematic diagram of an inhalation trigger control apparatus according to an embodiment of the present invention.

detailed description

It should be noted that the features in the embodiments and the embodiments in the present application may be combined with each other without conflict. The invention will be described in detail below with reference to the drawings in conjunction with the embodiments.

1 is a flow chart of a method of inhalation trigger control according to an embodiment of the present invention.

As shown in FIG. 1, the method includes the following steps:

Step S102: During the exhalation process, the parameter values in the airway are monitored.

Step S104: Determine whether the parameter value reaches a trigger value.

Preferably, monitoring the parameter values in the airway comprises: monitoring a change amount of the parameter value in the air channel, and determining whether the parameter value reaches the trigger value comprises: determining whether the change amount of the parameter value in the air channel reaches the trigger sensitivity.

Step S106, determining whether to perform the conversion of exhalation to inhalation according to the result of the judgment.

Preferably, determining whether to perform the conversion of exhalation to inhalation based on the result of the determining comprises: determining a timing of transition from exhalation to inhalation using a pressure trigger or a flow triggering mechanism.

Preferably, the parameter values in the airway include: a pressure in the airway; or a flow rate in the airway.

Preferably, before determining whether the parameter value reaches the trigger value, the method further includes: receiving parameter information input by the user; and obtaining the trigger value according to the parameter information. The ventilator ventilates the patient. In order to ensure that the ventilator air supply is synchronized with the patient's spontaneous inhalation, during the exhalation phase, it is necessary to estimate whether the patient has reached a certain trigger sensitivity by monitoring the pressure or flow in the airway and determining whether their changes have reached a certain trigger sensitivity. Start inhaling, and then decide whether to switch from exhalation to inhalation.

The invention continuously adjusts the flow triggering sensitivity in the exhalation process by a mechanism for learning the patient's exhalation time, so that the trigger sensitivity monotonously decreases with the exhalation process, thereby reducing false triggering and patient ineffective inspiration, and improving human-machine performance. Inhalation synchronization. Holding mode (PSV;), continuous positive airway pressure (CPAP), auxiliary/controlled ventilation mode (A/C:), synchronized intermittent command ventilation mode (SIMV), etc.

Preferred embodiments of the invention are described below.

This technical solution aims to solve the dilemma of trigger sensitivity setting under the traditional flow trigger mechanism: Setting a large trigger sensitivity will reduce false triggering but at the same time increase the patient's inspiratory triggering power, which will result in a large inspiratory hysteresis or even invalid patient. Inspiratory work; on the contrary, setting a small trigger sensitivity will reduce the patient's inspiratory triggering work, but it will cause false triggering.

Taking Pressure Support Mode (PSV) as an example, the typical flow pressure waveform in ventilation is shown in Figure 2. There are two distinct features when the patient begins to inhale: a decrease in airway pressure and an increase in flow. When the flow triggering mechanism is adopted, if the monitored flow rate is greater than the set flow trigger sensitivity, the exhalation to inspiration is converted, and the action of this conversion is also called triggering.

In order to avoid false triggering, a high flow trigger sensitivity is often set, which is at the expense of wasting the patient's inspiratory effort. As shown in Figure 3, the common false trigger waveform does not actually have the distinct feature of patient inhalation, ie, the airway pressure drops. Therefore, according to the understanding of the actual false trigger waveform characteristics, the proposed flow trigger mechanism combines the airway pressure drop judgment as the criterion for exhalation to inspiration conversion, that is, only when the flow rate is greater than the set flow trigger sensitivity and occurs simultaneously. Airway pressure is below a certain fixed threshold Trigger only when the value is reached. By doing so, it is possible to set a lower flow sensitivity without causing false triggering, thus saving the patient's inspiratory effort.

Although combined with reduced airway pressure, most of the false triggers can be reduced with sufficient sensitivity to trigger, but false triggers due to small sensitivity settings can still occur. In view of this, this patent proposes an adaptive flow triggering mechanism based on patient's voluntary exhalation time learning, which fundamentally solves the contradiction of flow sensitivity setting.

The core idea of this technology is shown in Figure 4. This idea stems from the recognition that for a patient with autonomous inspiratory triggering, his breathing cycle, it can also be said that the expiratory cycle is stable for a period of time. Therefore, the flow trigger sensitivity can be set based on a pre-judgment of the patient's inspiratory start time, i.e., a smaller trigger sensitivity is set at the time when the patient is most likely to inhale, and a larger trigger sensitivity is set before this time. The pre-judgment of the patient's inspiratory start time is based on the previous breath exhalation time in the learning ventilation.

As shown in Figure 4, at the beginning of each exhalation, there is a trigger limit segment TElim, during which no trigger judgment is made, which is the strategy adopted by most existing ventilators, that is, this period is The conversion of exhalation to inhalation is not allowed. TElearn is the patient's voluntary exhalation time learned through previous ventilation cycles. When the exhalation is greater than TElim less than TElearn, the flow trigger sensitivity is monotonically decreasing. Three sensitivity decreasing curves are given here, as shown in Figures 2, 3, and 4, respectively. These three decreasing curves are linear, exponential, and piecewise decrementing curves.

For curve 1, that is, the linear regression curve of sensitivity, the formula for calculating the trigger sensitivity at time t (TElim ≤ t ≤ TElearn) is as follows:

ITS(t)=ITSset-[(ITSset-ITSmin)/(TElearn-TElim)] *(t-TElim) ( l )

For curve 2, that is, the sensitivity index decreasing curve, the formula for calculating the trigger sensitivity at time t (TElim ≤ t ≤ TEleam) is as follows: IT S (t)=IT S set-(ITS set-IT Smin) * exp[(t-TElearn)/x] where the time constant in the exponential function exp port can be set to a constant value as the case may be.

For curve 3, the sensitivity segmentation decrement curve, the trigger sensitivity of 1 time (1^ ₀ ≤ 1£1^ ₁ ) is calculated as follows:

ITS(t)=ITSset,TElim < t < Tb

ITS(t)=ITSmin,t>Tb ( ₃ ) where Tb represents a certain time close to TElearn, and can be set to a constant value as the case may be.

The block diagram of the technical solution is shown in FIG. 5, wherein the calculation in process 1 is as in the above formulas (1), (2),

(3) Given. The TElearn update formula for each ventilation in Process 2 is as follows:

TElearn(i)=a*TElearn(il)+(la)*TEi (4) where TElearn(i) represents the patient's voluntary expiration time for this ventilatory cycle learning update, TEi represents the current expiratory time, α is The constant between, preferably, is taken as 0.8 here. It should be noted that the steps shown in the flowchart of the accompanying drawings may be performed in a computer system such as a set of computer executable instructions, and, although the logical order is shown in the flowchart, in some cases, The steps shown or described may be performed in an order different than that herein.

According to an embodiment of the present invention, an inhalation trigger control device is provided.

Figure 6 is a schematic illustration of an inhalation trigger control device in accordance with an embodiment of the present invention.

As shown in FIG. 6, the apparatus includes: a monitoring module 602, a determining module 604, and a determining module 606. The monitoring module 602 is configured to monitor a parameter value in the airway during the exhalation process; the determining module 604 is configured to determine whether the parameter value reaches a trigger value; and the determining module 606 is configured to determine whether to perform an exhalation direction according to the result of the determining Inspiration conversion.

Preferably, the parameter values in the air passage include: a pressure in the air passage; or a flow rate in the air passage. Preferably, the inhalation trigger control device further includes: a receiving module, configured to receive parameter information input by the user; and an obtaining module, configured to obtain the trigger value according to the parameter information.

An embodiment of the present invention also provides a ventilator. Wherein, the ventilator comprises the inhalation trigger control device described above.

From the above description, it can be seen that the present invention realizes simple control of the inhalation trigger. Further, the present invention fundamentally overcomes the human-machine trigger unsynchronization caused by the trigger sensitivity compromise setting in the conventional flow trigger mechanism. Problems such as inspiratory hysteresis, ineffective patient inhalation work and false triggering. That is to say, this trigger mechanism can ensure that the patient's inspiratory triggering work is minimized without causing false triggering. Further, the present invention can change the setting interface of the conventional flow triggering mechanism, that is, the maximum flow trigger sensitivity is still set by the ventilator user. Further, the amount of calculation required for the technical solution of the present invention is small.

Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device, or they may be separately fabricated into individual integrated circuit modules, or they may be Multiple modules or steps are made into a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A control method for inhalation triggering, comprising: monitoring a parameter value in an airway during exhalation; determining whether the parameter value reaches an inspiratory trigger value that varies with a patient's voluntary exhalation cycle And determining whether to perform the conversion of exhalation to inhalation based on the result of the judgment.

The control method of the inhalation trigger according to claim 1, wherein the parameter value in the air passage includes: a pressure in the air passage; or a flow rate in the air passage.

The method of controlling the inspiratory trigger according to claim 1, wherein the monitoring the parameter values in the airway comprises: monitoring a change amount of the parameter value in the air channel, and determining whether the parameter value reaches a trigger value comprises: : Determine whether the amount of change in the parameter value in the airway reaches the trigger sensitivity.

The control method of the inspiratory trigger according to claim 1, wherein determining whether to perform the exhalation to inspiration conversion according to the result of the determining comprises: using a pressure trigger or a flow triggering mechanism to determine the exhalation The timing of the conversion to inhalation.

The method of controlling the inspiratory trigger according to claim 1, wherein before determining whether the parameter value reaches a trigger value, the method further comprises: receiving parameter information input by the user; The trigger value is obtained according to the parameter information.

6. The control device for inhalation triggering, comprising: a monitoring module, configured to monitor a parameter value in the airway during the exhalation process; and a determining module, configured to determine whether the parameter value reaches a trigger value; And a determining module, configured to determine whether to perform the conversion of exhalation to inhalation based on the result of the determining.

The control device for inhalation trigger according to claim 6, wherein the parameter value in the air passage includes: a pressure in the air passage; or a flow rate in the air passage.

The device for controlling the inspiratory trigger according to claim 6, further comprising: a receiving module, configured to receive parameter information input by the user; and an obtaining module, configured to obtain the trigger according to the parameter information value.

A ventilator, comprising the control device for inhalation triggering according to any one of claims 6 to 8.