Ventilation system with improved valves

Abstract

1. A respiratory ventilator system having an inlet configured to be connected to a pressurized air or gas source; an outlet configured to be connected to a patient interface; an in-line valve between the inlet and the outlet; and a controller configured to control the valve to control the flow of pressurized air or gas from the source to a patient, the valve including an air or gas reservoir or accumulator integrated within the valve body.

Description

[Technical field]

[0001] The present disclosure relates generally to respiratory management systems, and more particularly to mechanical ventilation or respiratory management systems, i.e., ventilators or respirator masks. The present disclosure has particular utility in providing respiratory assistance to human or animal patients whose breathing is impaired by disease and will be described in connection with such utility, but may also be utilized for the treatment of patients suffering from sleep apnea or for use as a component of anesthesia systems. [Background technology]

[0002] The current Covid-19 pandemic has highlighted the need for mechanical ventilation systems for patients with respiratory disorders. Respiratory therapy devices can serve to provide a patient with a supply of clean breathable gas (usually air, with or without supplemental oxygen) at a therapeutic pressure, timed appropriately during the subject's respiratory cycle. Therapeutic pressure support can be performed in a synchronized manner with the patient's breathing, such that the pressure can be higher during the patient's normal inspiratory cycle and lower during exhalation. Therapeutic pressure support can also be performed to override the patient's normal expiratory cycle.

[0003] A respiratory management system generally includes a gas or airflow generator or source of compressed gas or air, an air filter, a nasal, oral or full face mask, an air delivery conduit connecting the flow generator to the mask, various sensors, and a microprocessor-based controller. Optionally, instead of a mask, a tracheotomy tube can serve as the patient interface. The flow generator may include a servo-controlled motor and impeller forming a blower. In some cases, braking of the blower motor can be implemented to reduce the blower speed more rapidly to overcome the inertia of the motor and impeller. The braking allows the blower to achieve a low pressure condition more quickly to synchronize with the patient's exhalation despite the inertia. In some cases, as an alternative to motor speed control, the flow generator can also include a valve that can be configured to vent the generated air to the atmosphere as a means to modify the pressure delivered to the patient. Sensors measure motor speed, mass flow rate, and outlet pressure, such as by pressure transducers, among others. The device may optionally include a humidifier and / or a heating element in the path of the air delivery circuit.The control device may include data storage capacity with or without integrated data retrieval and display capabilities.

[0004] Respiratory management systems can be utilized to treat many conditions, such as respiratory failure due to pulmonary, neuromuscular, or musculoskeletal disorders of respiratory control. Respiratory management systems can also be utilized to treat conditions associated with sleep-disordered breathing (SDB), including mild obstructive sleep apnea (OSA), allergy-induced upper airway obstruction, or early viral infection of the upper airway.

[0005] The current Covid-19 pandemic has stretched the current supply of respiratory management systems. Hospitals have been forced to share respiratory management systems, i.e. ventilators, between two patients. Hospitals have also adapted traditionally available devices for obstructive sleep apnea as inferior substitutes for traditional ventilators.

[0006] Additionally, current ventilators are complex, expensive devices that require regular monitoring and adjustment, and are prone to malfunctions. Summary of the Invention [Problem to be solved by the invention]

[0007] The current disclosure provides a simple, low-cost ventilator that overcomes the above-mentioned and other shortcomings of current state-of-the-art ventilators.

[0008] More specifically, the present disclosure provides a ventilator that has significant advantages over current ventilators in terms of cost, reduced size, weight reduction, power reduction, noise reduction, and reliability. One of the key features of this ventilator of the present disclosure is a unique air or gas flow valve with an internally incorporated air or gas reservoir or accumulator. The incorporation of the air or gas reservoir or accumulator in the valve simplifies the structure and cost of the system while providing better patient support by improving response time. Conventional ventilators employ proportional solenoid valves (PSOL valves) or turbine-based designs where the core flow / pressure regulating component is a costly multi-part component (around $1,500-$2,000). In practice, the static friction of the plunger guide post of a conventional PSOL valve can impair the sensitivity of the valve, resulting in hysteresis effects. To overcome these and other shortcomings of conventional ventilators, the present disclosure employs a novel, low-cost air or gas valve that has an integral air or gas reservoir or accumulator built therein and is comprised of essentially five basic members and essentially one moving part. [Means for solving the problem]

[0009] In one embodiment, the respiratory ventilator system of the present disclosure includes an inlet configured to be connected to a pressurized air or gas source; an outlet configured to be connected to a patient interface; an in-line valve between the inlet and the outlet; and a controller configured to control the valve to control the flow of pressurized air or gas from the source to the patient, the valve including an air or gas reservoir or accumulator integrated within the valve body.

[0010] In one preferred embodiment, the valve includes a valve gate controlled by a linear drive mechanism, preferably a servo mechanism, a mechanical screw drive or a voice coil drive.

[0011] The patient interface may be selected from the group consisting of a mask, an intubation tube and a tracheostomy cannula, and the pressurized air or gas source may be selected from the group consisting of an air can, a compressor, an air pump and a pressurized air tube.

[0012] The present disclosure also provides a method for assisting the breathing of a patient in need of breathing, comprising the steps of providing a ventilator system as described above; connecting the ventilator system to a source of pressurized air and a patient interface; and initiating pre-charging of the air or gas reservoir or accumulator with air or gas flow to the ventilator system and controlling the gas flow through the ventilator system by opening and closing the valve.

[0013] In another embodiment of the present disclosure, the ventilator system includes a heater and / or humidifier for conditioning the air or gas.

[0014] The valve may open and close in response to the patient's normal breathing cycle, or the valve may open and close to admit air or gas flow to override the patient's normal breathing cycle.

[0015] The patient may be a human animal; or a non-human animal.

[0016] Further features and advantages of the present disclosure will be understood from the following description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram of a ventilator system incorporating a miniature ventilator shown connected to a patient in accordance with the present disclosure; [Diagram 2] FIG. 1 is a perspective view of a compact ventilator made in accordance with the present disclosure; [Diagram 3] FIG. 1 is a cross-sectional view of a functional component diagram of a valve component of a compact ventilator according to a preferred embodiment of the present disclosure. [Figure 4] FIG. 1 is a functional element cross-sectional view of a valve component of a compact ventilator according to the present disclosure. [Diagram 5] FIG. 1 is a functional element cross-sectional view of a valve component of a compact ventilator according to the present disclosure. [Figure 6] FIG. 1 illustrates force and moment balance of the valve components of the present disclosure. [Figure 7] FIG. 2 is an exploded view of valve components according to the present disclosure. [Figure 8] FIG. 1 is a flow diagram illustrating operation of the compact ventilation device of the present disclosure. [Figure 9] 9A-9C are graphs of internally induced airflow in accordance with the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] In the detailed description that follows, the terms "air" and "gas," and the terms "respiratory mask" and "respirator," respectively, are used interchangeably.

[0019] The respiratory treatment devices of the present disclosure provide supplemental air or oxygen to a patient at intermittent time intervals based on either the patient's natural cyclical breathing cycle or a programmed breathing cycle.

[0020] With reference to FIG. 1, a respiratory ventilator system 10 includes a ventilation controller 12 connected to a pressurized gas source 14. The pressurized gas source may be a pressurized air or air-oxygen gas canister, a compressor or air pump as shown, or a pressurized air tube. The ventilation controller 12, described in detail below, enables pressurized gas flow to a patient through a gas supply tube 16 secured to a patient interface, such as a nasal or full face mask 18 worn by the patient 22. Alternatively, the patient interface 18 may include an intubation tube or tracheotomy cannula. Completing the system is a capnography monitor 24 that senses and measures inhaled and / or exhaled air from the patient, and a command input monitor 26. The capnography monitor 24 and the command input monitor 26 are conventional and need not be described further for an understanding of the present disclosure.

[0021] Central to the ventilator system 10 of the present disclosure is a gas or air flow control valve 28 with an integral gas or air reservoir or accumulator, described below.

[0022] 3-5, the gas or air flow control valve 28 includes a valve housing 40 which houses the active elements of the gas or air flow control valve 28. A gas supply inlet 42 is shown in the negative X-axis plane and a gas supply outlet 44 is shown in the positive X-axis plane. Alternatively, the housing 40 forms a gas reservoir or accumulator 46. The gas supply inlet 42 may be coupled to a standard hospital oxygen supply or any gas supply, such as a gas canister or compressor.

[0023] Valve gate 48, described below with respect to Figures 3 and 4, controls the source flow rate, QSource(t), based on its position along the X-axis. A face on the negative Z surface slides along the X-axis on a valve housing sliding surface 50. The distance δ between the valve gate face on the positive X-axis of the gate and the valve housing sealing surface 52 determines the flow resistance by forming a resistance channel between the valve housing sealing surface and the valve gate YZ face on the positive X-axis.

[0024] 5 and 7, the gas or air flow control valve 28 includes a valve gate 48 configured to slide along the X-axis with a valve sliding surface 50 setting its position along the X-axis. The gas or air flow control valve 28 also includes a linear actuator 54, such as an electrostrictive material such as PZT (lead zirconate titanate) or PMN (lead magnesium niobate), a servo mechanism formed from a magnetostrictive material, or a voice coil drive mechanical screw drive or other linear drive mechanism. Its length and resulting gate valve position are determined by the desired source flow rate Q. 供給源 (t) or source flow pressure P 供給源 (t). The valve gate 48 can also be actuated under open loop control.

[0025] A negative X-direction preload force is applied to the valve gate 48 by the spring assembly 56 .

[0026] Set screw 50 drives valve gate 48 in the X direction and sets both the spring assembly preload force and the initial position of valve gate 48 along the X axis.

[0027] The spring plunger 58 provides a negative Z preload on the valve gate 48 to continuously maintain an air tight seal between the valve gate 48 and the valve housing sliding surface 58.

[0028] The gasket 60 maintains an air-tight seal between the XZ face of the valve housing and the valve gate 48 .

[0029] Referring again to FIG. 2, the ventilation control device 12 includes an air or gas input port 30 connected to a gas or air flow control valve 28. The control valve 28 has an outlet 32 ​​connected to a port containing an inspiratory flow connection 34, and an expiratory flow port 36 further connected to an expiratory flow valve 38. The expiratory flow valve 38 may be vented to atmosphere or may be connected to scrub carbon dioxide and recycle it through the gas input port 30. The system also includes an expiratory flow or breath sensor 40 for sensing the patient's breath and a connection from the sensor for actuating the valve 28. The sensor may include an air flow sensor, a temperature sensor, a sound sensor, a carbon dioxide sensor, or a motion or strain sensor for detecting movement of the patient's chest.

[0030] Valve covers 62 surround the XZ plane of the valve housing, one on the positive Y axis and one on the negative Y axis. These covers form an airtight seal between the valve housing 40 and the atmosphere.

[0031] Referring again to FIGS. 4-6, on the left side of FIG. 4, the valve is shown in a closed position δ=0, with the valve flow resistance R 弁 (0) is infinity. Figure 4 shows a valve assembly with the gate moved a distance δ in the negative direction along the X-axis. As a result, the valve resistance is no longer infinite and gas will flow from the reservoir to the gas source as shown.

[0032] Valve flow resistance, R 弁 (δ) is calculated as follows: Source flow rate, Q 供給源 (t) is governed by Equation 3. Reservoir pressure, P リザーバ (t) Outlet pressure, P 出口 (t) Source flow rate, Q 供給源 (t) Valve height, H 弁 Valve depth along the Y axis, D 弁 Valve gate distance from valve housing seal face, δ A 抵抗(δ) = Resistance channel cross section (Equation 1) =D 弁 δ Gas dynamic viscosity, η(mass / (distance-time)) R 弁 (δ) = valve flow resistance due to the resistance channel =(8η / π)H 弁 / A 抵抗 (δ) 2 Equation 2) The source flow rate can then be determined by the following relationship: Q 供給源 (t)=(P リザーバ (t)-P 出口 (t)) / R 弁 (δ) Equation 3)

[0033] Average source flow rate Q 供給源 (t) is the effective supply flow rate Q 供給 (t) but not exceeding Q 供給源 The peak flow rate of (t) exceeds the required gas reservoir area within the valve housing. This difference results from the gas stored in the reservoir.

[0034] The force and moment balance of a generic valve gate is shown in Figure 5. The governing equations for both force balance and moment balance are shown in Equations 4-12. P リザーバ = Reservoir pressure θ = valve gate angle W = valve gate width H = Valve gate height H 弁 =H / Cosθ Equation 4) D 弁 = Valve gate depth L1, L2 and L3 = Spring distances c 摩擦 = Wedge friction coefficient Z アクチュエータ = Actuator distance from Z=0 P リザーバ = Reservoir gas pressure F 圧力X = Force from chamber pressure in X direction =-P リザーバ HD Equation 5) F 圧力Z = Force from chamber pressure in Z direction =-P リザーバ (WD+Htanθ D / 2) Equation 6) F プランジャー = Force from spring plunger in Z direction P レジスタ (Z) = pressure along the flow register wall ≒P リザーバ (Z / H) Equation 7) F Pレジスタ = force on register wall from pressure due to flow =(P リザーバ / 2)D 弁 H 弁 Equation 8) F スプリング = force applied by the preload spring F アクチュエータ = force applied by the positioning actuator Z force balance F Z =F プランジャー +F 圧力Z +3F スプリング Sinθ Equation 9) F 摩擦 = Friction force in the X direction =F Z c 摩擦 Equation 10) X force balance (3F スプリング +F Pレジスタ )Cosθ=F 圧力X +F アクチュエータ Equation 11) Moment balance about the Y axis F スプリング (L1+L2+L3)Cosθ 2 +F Pレジスタ ((2 / 3)H / Cosθ)Cosθ 2 =F 圧力X H / 2+F アクチュエータ Z アクチュエータ Equation 12)

[0035] Also, referring to FIG. 7, the valve assembly 28 has a flow resistance R 弁The source gas flow is controlled by varying the reservoir pressure P (δ). This is accomplished by changing the length ΔX of the actuator 54, which moves the valve gate 48 by δ along the X axis, creating a corresponding gap between the valve gate 48 and the valve housing seal surface 52. リザーバ (t) is monitored and, as outlined by Equation 3, Q 供給源 This is utilized by pressure sensor 70 to calculate the required ΔX command to control (t).

[0036] The gas has a source flow rate Q which is a function of time t 供給源 The gas flows straight through a flow sensor that measures Q(t) to the gas supply inlet 42. This flow measurement is calculated using the 供給源 It is utilized by the gas source controller and sensor / user interface to calculate the required ΔX command to control (t).

[0037] As with conventional ventilators, the inlet gas or flow rate may require humidification and / or heating. This is accomplished by commands from the controller to a humidification and heating module 72, which communicates with the reservoir 46 and adds water vapor to add humidity to the gas stream, either by heating and subsequent evaporation of the water, piezoelectric atomization of the water, or other conventional methods of adding water to the gas stream. The gas can also be heated as it flows by this module.

[0038] The gas flows through a relative humidity sensor that measures the gas relative humidity RH(t) as a function of time t. This measurement is used to calculate the desired RH command as a function of time RH コマンド This is used by the controller to generate (t).

[0039] The temperature and pressure source module measures the gas temperature T(t). This temperature measurement generates a heating command T to the humidification and heating module to control the gas temperature. コマンド It is used by the controller and the sensor / user interface to calculate (t).

[0040] The temperature and pressure source module supplies the gas outlet pressure P 出口 (t) can also be measured. This pressure is expressed as Q, as outlined by Equation 3. 供給源 This is utilized by the controller and sensor / user interface to calculate the required ΔX command which controls (t). The outlet of the temperature and pressure module connects to a gas supply terminating in a pressurized nasal ventilator or other patient breathing apparatus such as a mask, cannula or intubation tube.

[0041] The gas source controller and sensor / user interface are 供給源 (t), pressure P 出口 The sensor interface includes the sensor interface required to control the actuator command ΔX(t), the temperature command T コマンド (t) and relative humidity command RH コマンド (t). The sensor interface generates the gas supply flow rate Q 供給源 (t), pressure P 出口 The gas source controller and sensor / user interface also couples to a user command input device and a status monitor that receives a user defined command set for T(t) and RH(t). The gas source controller and sensor / user interface also provides sensor signals to the user command input device and the status monitor.

[0042] A user command input device and status monitor allow the user to control the gas supply flow rate Q 供給源 (t), pressure P 出口 Commands for T(t), T(t) and RH(t) can be generated. The user command input device and status monitor also displays the sensor signals. This device may be an iPad®-like interface that communicates with the pressurized nasal ventilator assembly in a wired or wireless manner.

[0043] The gas supply tube may be standard oxygen tubing. The gas supply tube may also be insulated to minimize gas heat loss during travel from the gas source to the pressurized nasal ventilator assembly. The gas supply tube may also incorporate a heating element to maintain gas temperature and may also incorporate a power and data wire set to provide power to the pressurized nasal ventilator assembly and to receive sensor data from the pressurized nasal ventilator assembly. The gas supply tube has a known flow resistance R GSL Therefore, the pressure P at the inlet point of the pressurized nasal ventilator gas port 供給源 (t) is the known Q 供給源 (t), P 出口 (t) and R GSL As a result of the equation P 供給源 (t)=P 出口 (t)-Q 供給源 (t)R GSL It can be calculated by:

[0044] Additional sensors can provide inputs to control the gas source assembly. These include the pressurized nasal ventilator assembly air chamber, the air chamber pressure P sampled from an impedance-based device that monitors respiratory rate and tidal volume through thoracic movement such as in the system. チャンバ (t), air chamber temperature T AC , air chamber relative humidity RH AC , ETCO2 (end tidal carbon dioxide partial pressure) and / or O2 measurements, but are not limited to these.

[0045] 8, the overall operation is as follows: The gas source 14 supplies pressurized gas to the ventilation controller 12 which opens the valve 28 to supply gas to the patient 22 at the frequency, flow rate and pressure required to support the patient's breathing. Due to the presence of a pressurized gas or air supply to an air or gas reservoir 46 integrated into the valve 28, the delivery of pressurized air or gas to the patient 22 proceeds essentially simultaneously with the opening of the valve. The air or gas reservoir 48 is refilled as the patient exhales.

[0046] The resulting ventilator system of the present disclosure is a low-cost, relatively simple device that is robust, advantageously small and lightweight, and very fast in responding to patient demands, as compared to conventional ventilation devices.

[0047] 9A-9C are flow and pressure waveforms showing three upstrokes (pressure support) of a patient.

Claims

1. an inlet configured to be connected to a source of pressurized air or gas; an outlet configured to connect to a patient interface; an in-line valve between the inlet and the outlet; a controller configured to control the valve to control the flow of pressurized air or gas from the source to the patient; the valve includes a sealable air or gas reservoir or accumulator; the sealable air or gas reservoir or accumulator is configured to store a predetermined amount of pressurized air or gas separate from the pressurized air or gas source, and the sealable air or gas reservoir or accumulator is configured to supply the stored predetermined amount of pressurized air or gas to the patient along with the pressurized air or gas from the pressurized air or gas source upon opening of a valve, thereby increasing the peak flow rate of the air or gas to the patient; 1. A respiratory ventilator system, wherein the sealable air or gas reservoir or accumulator is configured to be filled with a stored amount of pressurized air or gas when a valve for controlling the flow of pressurized air or gas to the patient is closed.

2. 10. The respiratory ventilator system of claim 1, wherein the valve includes a valve gate controlled by a linear drive mechanism that is a mechanical screw drive or a voice coil drive.

3. 10. The respiratory ventilator system of claim 1, wherein the patient interface is selected from the group consisting of a mask, an intubation tube, and a tracheostomy cannula.

4. 10. The respiratory ventilator system of claim 1, wherein the pressurized air or gas source is selected from the group consisting of an air can, a compressor, an air pump, and a pressurized air line.

5. 10. The respiratory ventilator system of claim 1, further comprising at least one of a heater and a humidifier for conditioning the air or gas.

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