Volume directed pressure control variable ventilation method, system and ventilator

Abstract

The present application relates to the technical field of medical devices, in particular to a pressure control variable ventilation method and system based on volume guidance and a breathing machine. The method comprises: step 1: a set tidal volume variation dV is added to a set ideal tidal volume VI to obtain a target tidal volume VT; step 2: a difference AV between a user actual tidal volume Vt of the current breathing cycle and the target tidal volume VT is obtained; step 3: an ideal pressure P of the current breathing cycle is calculated based on the difference AV; a pressure variation dP of the current breathing cycle is calculated based on the difference AV; step 4: a driving pressure AP of a ventilation device is calculated through the ideal pressure P of the current breathing cycle and the pressure variation dP of the current breathing cycle, and the ventilation device is controlled to operate based on the driving pressure AP in the next breathing cycle; and step 5: the next breathing cycle in step 4 is regarded as the current breathing cycle in step 2, and the method returns to step 2 until the user actual tidal volume Vt reaches the target tidal volume VT.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a volume-targeted pressure-controlled variable ventilation method, system and ventilator. BACKGROUND

[0002] Mechanical ventilation plays a significant role in the technical field of medical devices. However, conventional mechanical ventilation modes can only provide fixed tidal volume or inspiratory pressure, and real spontaneous breathing has certain variability, which will intermittently appear sigh, and its tidal volume, respiratory rate and inspiratory flow rate will fluctuate within a certain range. The existing mechanical ventilation gas delivery method is relatively single, which is completely different from spontaneous breathing.

[0003] Variability is a compensatory ability of biological organisms to adapt to changes in the external environment. Under healthy conditions, the heart rate, arterial blood pressure, respiratory rate, lung ventilation and blood flow distribution, and white blood cell count of biological organisms all have significant variability. Studies have shown that in healthy adults, the variability of tidal volume, respiratory rate and inspiratory time during spontaneous breathing in a calm state is 33%, 21% and 18% respectively, and this variability can maintain the ventilation balance of the body, reduce lung stress and strain, and is very beneficial to the human body.

[0004] Under certain conditions, the intrinsic variability of the respiratory system of biological organisms will decrease. Mechanical ventilation cannot adapt to these variability changes due to its single gas delivery method, and the decrease in respiratory variability of mechanical ventilation users can easily lead to weaning failure. SUMMARY

[0005] The purpose of the present application is to overcome the inability to adapt to changes in the respiratory variability of users, thereby providing a volume-targeted pressure-controlled variable ventilation method, a volume-targeted pressure-controlled variable ventilation system and a ventilator comprising the system.

[0006] To solve the above technical problems, the volume-targeted pressure-controlled variable ventilation method provided by the technical solution of the present application relates to a ventilation device, comprising:

[0007] Step 1: adding a set tidal volume variability dV to a set ideal tidal volume VI to obtain a target tidal volume VT;

[0008] Step 2: obtaining the difference AV between the actual tidal volume Vt of the user in the current breathing cycle and the target tidal volume VT,

[0009] Step 3: Calculate the ideal pressure P of the current breath cycle by the difference ΔV and the ideal pressure Ppre of the last breath cycle; calculate the pressure variation dP of the current breath cycle by the difference ΔV and the pressure variation dPpre of the last breath cycle;

[0010] Step 4: Calculate the driving pressure ΔP of the ventilation device by the ideal pressure P of the current breath cycle and the pressure variation dP of the current breath cycle, and control the ventilation device to operate based on the driving pressure ΔP in the next breath cycle;

[0011] Step 5: Take the next breath cycle in step 4 as the current breath cycle of step 2, and return to step 2 until the actual tidal volume Vt of the user reaches the target tidal volume VT.

[0012] As an improvement of the above method, the step 1 specifically comprises:

[0013] VT= VI + dV x a

[0014] Wherein, a is a Gaussian coefficient subject to normal distribution.

[0015] As an improvement of the above method, the step 2 specifically comprises:

[0016] Calculate the actual tidal volume Vt of the user by the actual inspiratory tidal volume Vti obtained by monitoring and the actual expiratory tidal volume Vte obtained by monitoring:

[0017] Vt = (Vti + Vte) / 2

[0018] Obtain the difference ΔV between the actual tidal volume Vt of the user in the current breath cycle and the target tidal volume VT

[0019] ΔV = Vt - VT.

[0020] As an improvement of the above method, the step 3 specifically comprises:

[0021] Calculate the ideal pressure P of the current breath cycle by the difference ΔV and the ideal pressure Ppre of the last breath cycle:

[0022] P = Ppre + k1 x ΔV

[0023] Wherein, k1 is a first parameter, k1 = -1 / (1000xC), C is the compliance of the respiratory system of the user obtained by monitoring; wherein, when the last breath cycle is the first breath cycle, the ideal pressure Ppre of the last breath cycle is:

[0024] Ppre = VI / C

[0025] The pressure variation dP of the current breath cycle is calculated by the difference AV and the pressure variation dPpre of the last breath cycle:

[0026] dP = dPpre + k2 x AV

[0027] wherein k2 is a second parameter, k2 = k1 / 100 x a, and a is a Gaussian coefficient subject to normal distribution; wherein when the last breath cycle is the first breath cycle, the pressure variation dPpre of the last breath cycle is:

[0028] dPpre = dV / C.

[0029] As an improvement of the above method, the step 4 specifically comprises:

[0030] The driving pressure AP of the ventilation system is calculated by the ideal pressure P of the current breath cycle and the pressure variation dP of the current breath cycle:

[0031] AP = P + dP x a

[0032] wherein a is a Gaussian coefficient subject to normal distribution;

[0033] The ventilation system is caused to operate based on the driving pressure AP in the next breath cycle.

[0034] To achieve another object of the present application, the present application further provides a volume-targeted pressure control variability ventilation system, comprising a ventilation device and a control module; wherein,

[0035] The control module is configured to add the set tidal volume variation dV to the set ideal tidal volume VI to obtain a target tidal volume VT; to obtain the difference AV between the monitored actual tidal volume Vt of the current breath cycle and the target tidal volume VT; to calculate the ideal pressure P of the current breath cycle by the difference AV and the ideal pressure Ppre of the last breath cycle; to calculate the pressure variation dP of the current breath cycle by the difference AV and the pressure variation dPpre of the last breath cycle; and to calculate the driving pressure AP of the ventilation device by the ideal pressure P of the current breath cycle and the pressure variation dP of the current breath cycle, and control the ventilation device to operate based on the driving pressure AP in the next breath cycle.

[0036] The ventilation device operates based on the driving pressure AP of the ventilation system and outputs a corresponding tidal volume.

[0037] To achieve another object of the present application, the present application further provides a breathing machine comprising the above volume-targeted pressure control variability ventilation system.

[0038] Compared with the prior art, the ventilation target of the present application adds a certain degree of variability, is more in line with the physiological needs of the user, and can adaptively adjust the pressure of the ventilation device to gradually reach the target tidal volume of the actual tidal volume of the user. The present application also adds a certain degree of variability in pressure regulation, which can improve the comfort of the user and is more conducive to accelerating weaning. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 A schematic diagram of the volume-guided pressure control variability ventilation method provided by the present application. DETAILED DESCRIPTION

[0040] The technical solutions provided by the present application are further illustrated below in combination with embodiments.

[0041] Embodiment 1

[0042] The present embodiment provides a volume-guided pressure control variability ventilation method, as shown in Figure 1 , comprising:

[0043] Step 1: Add the set tidal volume variability dV to the set ideal tidal volume VI to obtain the target tidal volume VT;

[0044] Step 2: Obtain the difference ΔV between the monitored actual tidal volume Vt of the user in the current breathing cycle and the target tidal volume VT,

[0045] Step 3: Calculate the ideal pressure P of the current breathing cycle by the difference ΔV and the ideal pressure Ppre of the previous breathing cycle, and calculate the pressure variability dP of the current breathing cycle by the difference ΔV and the pressure variability dPpre of the previous breathing cycle;

[0046] Step 4: Calculate the driving pressure ΔP of the ventilation device by the ideal pressure P of the current breathing cycle and the pressure variability dP of the current breathing cycle, and control the ventilation device to operate based on the driving pressure ΔP in the next breathing cycle;

[0047] Step 5: Take the next breathing cycle in step 4 as the current breathing cycle of step 2, and return to step 2 until the actual tidal volume Vt of the user reaches the target tidal volume VT.

[0048] The method can be implemented by the following specific steps.

[0049] 1. Obtain the operator input parameters. The system is volume-guided, i.e. to achieve the user tidal volume desired by the operator, so the input parameters include the ideal tidal volume VI and the tidal volume variability dV.

[0050] 2. Generate a Gaussian coefficient a that obeys a normal distribution, so the target tidal volume VT is:

[0051] VT = VI + dV x a

[0052] Thus, a certain variability is added to the tidal volume of the user.

[0053] 3. The actual tidal volume Vt of the user is monitored by the flow sensor:

[0054] Vt = (Vti + Vte) / 2

[0055] Wherein, Vti is the inhaled tidal volume of the user monitored, Vte is the exhaled tidal volume of the user monitored, and the average of the two is taken as the actual tidal volume of the user.

[0056] 4. The difference AV between the actual tidal volume of the user and the target tidal volume is obtained:

[0057] AV = Vt - VT

[0058] 5. The system is essentially pressure-controlled ventilation, that is, by adjusting the driving pressure AP from breath to breath, so that the actual tidal volume Vt of the user approaches the target tidal volume VT; wherein,

[0059] AP = P + dP x a

[0060] Wherein,

[0061] P = Ppre + k1 x AV

[0062] dP = dPpre + k2 x AV

[0063] k1 = -1 / (1000 x C)

[0064] k2 = k1 / 100 x a

[0065] Wherein, k1 is the first parameter, k2 is the second parameter, P is the ideal pressure of the current breath, Ppre is the ideal pressure of the previous breath, dP is the pressure variability of the current breath, dPpre is the pressure variability of the previous breath, and C is the compliance of the user's respiratory system obtained by real-time monitoring. The initial value of the ideal pressure is VI / C, and the initial value of the pressure variability is dV / C.

[0066] The above parameters are updated from breath to breath, and by adjusting the driving pressure AP, the actual tidal volume Vt of the user gradually reaches the preset target tidal volume VT.

[0067] 6. After the actual tidal volume Vt reaches the preset target tidal volume VT, return to step 2 to repeat the above process. By continuously adjusting, the variability of ventilation can be achieved.

[0068] Example 2

[0069] The embodiment provides a volume-targeted pressure control variable ventilation system, comprising a ventilation device and a control module; wherein,

[0070] The control module is used for adding a set tidal volume variation dV to a set ideal tidal volume VI to obtain a target tidal volume VT; is used for obtaining a difference AV between a monitored actual tidal volume Vt of a current breathing cycle of a user and the target tidal volume VT, is used for calculating an ideal pressure P of the current breathing cycle by using the difference AV and an ideal pressure Ppre of a previous breathing cycle, and is used for calculating a pressure variation dP of the current breathing cycle by using the difference AV and a pressure variation dPpre of the previous breathing cycle; is used for calculating a driving pressure AP of the ventilation device by using the ideal pressure P of the current breathing cycle and the pressure variation dP of the current breathing cycle, and is used for controlling the ventilation device to operate based on the driving pressure AP in a next breathing cycle;

[0071] The ventilation device operates based on the driving pressure AP of the ventilation system and outputs a corresponding tidal volume.

[0072] Embodiment 3

[0073] The embodiment provides a breathing machine, which comprises the volume-targeted pressure control variable ventilation system provided in the embodiment 2.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application is described in detail with reference to the embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and all the modifications or replacements should be included in the scope of the claims of the present application.

Claims

1. A volume directed pressure controlled variable ventilation system comprising a ventilation device, characterized in that, Also comprising: a control module; wherein, the control module is configured to add a set tidal volume variability dV to a set ideal tidal volume VI to obtain a target tidal volume VT; to obtain a difference AV between a monitored actual tidal volume Vt of the current breath of the user and the target tidal volume VT, to calculate an ideal pressure P of the current breath by the difference AV and an ideal pressure Ppre of the last breath, to calculate a pressure variability dP of the current breath by the difference AV and a pressure variability dPpre of the last breath, and to calculate a driving pressure AP of the ventilation device by the ideal pressure P of the current breath and the pressure variability dP of the current breath, and to control the ventilation device to operate based on the driving pressure AP in the next breath; the ventilation device operates based on the ventilation system driving pressure AP and outputs a corresponding tidal volume; the process of adding a set tidal volume variability dV to a set ideal tidal volume VI to obtain a target tidal volume VT by the control module comprises: VT = VI + dV x a wherein a is a Gaussian coefficient subject to normal distribution; the process of calculating an ideal pressure P of the current breath by the difference AV and an ideal pressure Ppre of the last breath and calculating a pressure variability dP of the current breath by the difference AV and a pressure variability dPpre of the last breath by the control module comprises: calculating an ideal pressure P of the current breath by the difference AV and an ideal pressure Ppre of the last breath: P = Ppre + k1 x AV wherein k1 is a first parameter, k1 = -1 / (1000 x C), and C is a compliance of the respiratory system of the user obtained by monitoring; wherein when the last breath is the first breath, the ideal pressure Ppre of the last breath is: Ppre = VI / C calculating a pressure variability dP of the current breath by the difference AV and a pressure variability dPpre of the last breath: dP = dPpre + k2 x AV wherein k2 is a second parameter, k2 = k1 / 100 x a, and a is a Gaussian coefficient subject to normal distribution; wherein when the last breath is the first breath, the pressure variability dPpre of the last breath is: dPpre = dV / C.

2. The volume orientation based pressure control variable ventilation system of claim 1, wherein, the process of obtaining a difference AV between a monitored actual tidal volume Vt of the current breath of the user and the target tidal volume VT by the control module comprises: calculating the actual tidal volume Vt of the user by a monitored actual inhalation tidal volume Vti and a monitored actual exhalation tidal volume Vte: Vt = (Vti + Vte) / 2 obtaining a difference AV between the actual tidal volume Vt of the current breath of the user and the target tidal volume VT AV = Vt - VT.

3. A breathing machine characterized by, The capacity-oriented pressure control variability ventilation system based on claim 1.

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