VENTILATOR FOR VENTILATING A PERSON

Description

[0001] The invention relates to a ventilation device which is designed for artificial, non-invasive (NIV) ventilation of a person and in particular contains a radial fan.

[0002] In ventilation technology, various types of ventilators are known, which differ in terms of their configurations and operating modes (see, for example, DE 10 2008 047 026 B4, WO 2009 / 112 076 A1, DE 10 2008 005 558 A1, and DE 10 2018 003 027 A1). The ventilation pressure of a ventilation gas can be generated in a ventilator, for example, by connecting it to a compressed gas reservoir (see, for example, BC Galbiati et al., 2020, arXiv:2003.10405) or by a blower. A radial blower can be used as a blower (see, for example, DE 200 16 769 U1), which has advantages due to its compact design. Relevant prior art documents are also: US 2019 / 269871 A1, US 2018 / 064894 A1, JP 2018 531716 A and WO 2018 / 204985 A1.

[0003] Modern ventilators typically implement BIPAP (Biphasic Positive Airway Pressure) ventilation, a pressure-controlled procedure in which ventilation is carried out at two different pressure levels, each set during inspiration or expiration. Compared to older volume-controlled procedures, pressure-controlled procedures have the key advantage of supporting the patient in their spontaneous breathing efforts during the weaning phase without any additional effort. Important ventilation parameters are therefore in particular the positive end-expiratory pressure (PEEP), which describes the positive pressure in the lungs at the end of expiration, and the maximum pressure that occurs during inspiration (peak pressure or Ppeak or PIP).

[0004] In many conventional ventilators, these pressure levels are adjusted by (proportional) valves. However, by design, these valves do not control the pressure itself, but rather the flow, which only results in the desired pressure in interaction with the patient's lung volume. In single-tube systems, for example, exhaled air can be removed near the breathing mask through a controlled leak, a passive differential pressure-controlled valve, or an active proportional valve to minimize CO2 rebreathing. In two-tube systems, active components can be integrated into the control unit, with the additional disadvantage of even higher costs.

[0005] However, the disadvantages are the extremely high complexity of the equipment (valves, hoses, additional filters to protect the environment), the sensors (dual flow measurement), and the algorithms (safety devices in case of power failure or malfunction), resulting in significantly higher costs or the lack of important diagnostic options, such as expiratory volume or the detection of a mask leak. For example, if mask leaks could be diagnosed online and were small enough, the breathing air could be tempered and humidified using simple HME (heat-moisture exchange) filters, which would eliminate further equipment costs for breathing air conditioning in times of resource scarcity.

[0006] Conventional ventilators, especially those used in intensive care, are typically expensive, complex devices, each specifically designed for the requirements of a specific application, such as in a hospital or an ambulance. The operation of conventional ventilators generally requires integration into existing intensive care technology and operation and monitoring by specialized personnel.

[0007] Pandemic lung diseases, such as the Covid-19 outbreak in 2020, create a need for ventilators with reduced costs, minimal technical effort, minimal commitment of clinical resources, and the widest possible range of applications.

[0008] The object of the invention is to provide an improved ventilator with a radial fan that avoids the disadvantages of conventional technologies. In particular, the ventilator should have a simplified design without functional limitations during use, be manufactured at reduced cost, have reduced power consumption, be operable as independently as possible from other devices, be operable automatically, and / or be easy to operate.

[0009] This object is achieved by a ventilation device having the features of the independent claim. Preferred embodiments and applications of the invention are set forth in the dependent claims.

[0010] According to a first general aspect of the invention, the stated object is achieved by a ventilation device configured for non-invasive ventilation of a person. The ventilation device comprises a radial fan with an inlet opening and an outlet opening. The radial fan is configured to receive ventilation air at the inlet opening and to provide the ventilation air with an adjustable ventilation pressure at the outlet opening. The ventilation pressure is preferably adjustable by adjusting the power of the radial fan, in particular the speed of the radial fan. Different ventilation pressures can be set in different breathing phases.

[0011] The ventilator further comprises a first breathing line (or peripheral-side breathing line) with a first end connected to the inlet opening of the radial fan and a second end arranged to receive inhaled air. Furthermore, the ventilator comprises a second breathing line (or patient-side breathing line) with a first end connected to the outlet opening of the radial fan and a second end configured for coupling to a breathing mask. Preferably, the second end of the second breathing line is equipped with a coupling device configured for connection to the breathing mask. Alternatively, the second end of the second breathing line is permanently connected to the breathing mask. The face mask can be part of the ventilator. The breathing mask is a face mask that can be fixed to the face of a ventilated person.Preferably, a non-ventilated breathing mask is provided, which comprises a face mask that fits hermetically on the face of the ventilated person so that, during undisturbed operation and correct fit, the person breathes exclusively via the patient-side breathing line and no or negligible air enters or exits from the sides.

[0012] The second breathing line is equipped with a sensor device that can measure at least one flow parameter in the second breathing line. A control device of the ventilation device, preferably at least one microprocessor circuit, is provided for controlling the radial fan in response to at least one output signal of the sensor device.

[0013] According to the invention, the radial fan and the second breathing line form a continuous bidirectional flow path, i.e., a flow path with two alternating flow directions. The radial fan and the second breathing line are each designed for opposite flow directions during the various breathing phases, in particular the inhalation phase and the exhalation phase. Optionally, the first breathing line, or at least a portion thereof up to an optionally provided valve device, is also part of the continuous bidirectional flow path.The flow directions include a first flow direction from the second end of the first breathing line via the radial fan to the second end of the second breathing line (inhalation phase) or a second flow direction from the second end of the second breathing line via the radial fan to the second end of the first breathing line (exhalation phase) or, optionally, to an expiratory valve between the radial fan and the first end of the first breathing line. The adjustable ventilation pressure at the outlet of the radial fan is an inhalation pressure or an exhalation pressure that is equal to or less than the inhalation pressure.

[0014] The inventor has discovered that exhalation can occur through the radial fan and against the working pressure of the radial fan, thus enabling the provision of a bidirectional flow path. The bidirectional flow path offers the advantage of significantly simplifying the design of the ventilator compared to conventional techniques. The patient-side breathing line can comprise a single breathing line, via which the ventilator is connected to the breathing mask. The provision of the bidirectional flow path also enables simplified sensor technology. With the sensor device locally concentrated on the second breathing line, all flow parameters required for controlling the ventilator can be recorded, thus simplifying the control of the ventilator.

[0015] Furthermore, according to the invention, the second breathing line is equipped with a filter device arranged for airflow filtering. The filter device comprises a filter, preferably a HEPA filter, through which the flow in the second breathing line passes. Advantageously, the filter device fulfills a dual function by providing the bidirectional flow path. First, the environment is protected from germs that could potentially escape from the patient, and second, the patient is protected from germs that could potentially migrate from the environment. By providing a single filter device, preferably with a single filter, the structure and operation of the ventilation device are further simplified.

[0016] Advantageously, the radial fan is miniaturizable, so that the ventilation device according to the invention creates a system that is easy to manufacture and capable of implementing an automated ventilation process with minimal technical effort (preferably a breathing mask, HEPA filter, and microprocessor-controlled radial fan) with a diameter of 10 cm or less, preferably 7 cm or less, and a mass of 100 g or less, preferably 60 g or less. Furthermore, an extremely low power consumption of, for example, approximately 12 W is enabled, which enables extended operation on a battery, such as a vehicle battery, in order to maintain functionality even in the event of an unstable electrical supply, e.g., under disaster conditions.

[0017] Also disclosed is a control method for controlling a radial fan for ventilating a person.

[0018] The control method comprises the steps of controlling the radial fan with a first control loop, with which a ventilation pressure at an outlet opening of the radial fan can be set to an inhalation pressure or to an exhalation pressure which is equal to or less than the inhalation pressure, and controlling the radial fan with a second control loop, with which at least one of a frequency of inhalation phases in which the inhalation pressure is formed at the outlet opening of the radial fan and a duty cycle of the duration of the inhalation phases relative to the duration of exhalation phases in which the exhalation pressure is formed at the outlet opening of the radial fan can be set.

[0019] Controlling the radial fan comprises setting a time function of the fan speed of the radial fan. The control method, with the implementation of the two control loops, comprises a control method that sets predetermined flow parameters (setpoints) based on output values ​​of the sensor device (actual values) in order to obtain the aforementioned variables: inhalation pressure, exhalation pressure, and frequency of inhalation phases and / or duty cycle of the duration of the inhalation phases relative to the duration of exhalation phases. Preferably, the control method or one of its embodiments controls the radial fan of the ventilator according to the first general aspect of the invention or one of its embodiments.

[0020] Also disclosed is a method for operating a ventilator according to the first general aspect of the invention or one of its embodiments, wherein the method comprises the steps of operating the radial fan, measuring at least one flow parameter with the sensor device, and controlling the radial fan with a control method according to the second general aspect of the invention or one of its embodiments. The method for operating the ventilator preferably protects a ventilation method for ventilating a person wearing a face mask coupled to the ventilator.

[0021] The inventor has discovered that regulating the radial fan makes it possible to fulfill all the desired functions of a ventilator and, with the control method and the ventilation method, to continuously cover the entire spectrum from pure spontaneous breathing to spontaneous breathing support to the area of ​​purely automatic ventilation in cases of complete respiratory insufficiency. The ventilation pressure generated by the ventilator advantageously depends only negligibly on the flow (amplitude and / or direction), so that the patient's bidirectional spontaneous breathing is not impeded and can be easily detected by changing the flow. Under these conditions, simple indicators also arise for synchronizing the ventilator with the patient's spontaneous breathing (a so-called open system).

[0022] Advantageously, the tidal volume or minute ventilation can be adjusted by adjusting the ventilation pressure (inspiratory pressure) (IPAP) and the ventilation rate (f) or the inspiration-expiration ratio (I:E ratio). Typical upper limits are, for example, IPAP < 30 mbar, f < 25 / min, and I:E < 1.

[0023] Advantageously, the sensor device in the second breathing line allows, in particular, the pressure as the innermost reference variable of the control circuits mentioned to be measured with high accuracy (better than 0.5 mbar) and, furthermore, the flow velocity to be measured with high accuracy (better than + / - 0.2 l / min).

[0024] According to a preferred embodiment of the invention, the flow path between the second end of the second breathing line and the inlet opening of the radial blower is free of valves. The flow path along the second breathing line is, in particular, branch-free. This advantageously allows the ventilation device to be constructed without a double hose and without an exhalation valve between the face mask and the radial blower, thereby minimizing the hose volume of the second breathing line, particularly between the filter device and the radial blower, and thus minimizing the rebreathing of CO2.

[0025] According to a further preferred embodiment of the invention, the first breathing line has a valve device, in particular a passive differential pressure-controlled outlet valve or an actively actuated three-way valve, between the inlet opening of the radial fan and the second end of the first breathing line. The valve device is arranged as an expiratory outlet for the outlet of exhaled air. Advantageously, a simple, passive expiratory valve can be arranged in the first breathing line, particularly preferably immediately in front of the first end of the first breathing line (suction inlet of the radial fan). A passive expiratory valve is an exhalation valve that opens to the environment when the internal expiratory pressure in the first breathing line is above atmospheric pressure and in one flow direction, and is otherwise closed, such as a differential pressure-controlled film valve.The suction inlet of the radial blower is thus advantageously automatically switched between the inlet for supplying oxygen (with humidification if necessary) and the expiratory outlet, depending on the direction of the airflow through the radial blower. This provides a particularly simple separation of inspiratory and expiratory air. The passive automatic switching is determined primarily by the flow resistance of the first airway line and an optionally provided breathing air conditioning device.

[0026] Advantageously, there are various options for supplying breathing air for the patient via the first breathing line. According to a first variant, the second end of the first breathing line can open into the vicinity of the ventilator. This advantageously makes the structure of the ventilator particularly compact and lightweight. Alternatively or additionally, according to a second variant, the second end of the first breathing line can be configured for connection to a breathing air reservoir, such as a compressed air cylinder with a pressure reducing valve. In this case, advantages arise from the defined supply of breathing air with a predetermined oxygen content up to pure oxygen.

[0027] Advantageously, according to a further embodiment of the invention, a breathing air conditioning device is coupled to the second end of the first breathing line. The breathing air conditioning device is a component adjacent to the interior of the first breathing line, which adjusts the composition and / or physical properties of the breathing air flowing in the first breathing line through physical and / or chemical interaction. The breathing air conditioning device is preferably designed to adjust at least one of the parameters humidity, temperature, and oxygen content of the inhaled air. For this purpose, the breathing air conditioning device preferably comprises a controllable supply unit for the introduction of water vapor or aqueous aerosol, optionally mixed with pharmaceutical active ingredients, a temperature control device (heating and / or cooling device), e.g. based on a resistance heating element and / or a Peltier element, ora controllable supply unit for the introduction of oxygen. The breathing air conditioning device can, for example, include an evaporative system with sterile water supply from disposable bags, as is known in the clinical field through infusion technology, or a commercially available humidification unit.

[0028] The breathing air conditioning device offers the advantage that the acceptance of ventilation and the patient's well-being can be increased if the breathing gas is humidified and / or tempered, especially if the patient reflexively breathes primarily through the mouth when experiencing shortness of breath. The function of an HME filter, which is inadequate in a conventional ventilation device, can be fulfilled by the breathing air conditioning device. Temperature control can involve heating the breathing lines and the radial fan using the tempered breathing air to at least 30°C, preferably at least 35°C, up to a physiologically acceptable temperature. This advantageously prevents condensate and germ formation in the system after humidification.

[0029] The temperature control device can be configured for the direct temperature control of the breathing air and / or the direct temperature control of the ventilation device, in particular the second breathing line. Temperature control of the ventilation device particularly effectively prevents the formation of condensate and germs.

[0030] If, according to a further variant of the invention, the filter device has a plug connection with the radial fan and / or the second breathing line, advantages for the use of the ventilation device arise, in particular for easy filter replacement. After use on a patient, the ventilation device can be easily prepared for a new patient by changing the filter and disinfecting the remaining parts. The plug connection can be lockable, e.g., have a bayonet lock, to prevent accidental separation of the ventilation device components.

[0031] According to an advantageous embodiment of the invention, the control device is equipped with an interface for receiving an output signal from an oxygen saturation sensor. Preferably, an oxygen saturation sensor is permanently connected to the ventilation device. Alternatively, a separate oxygen saturation sensor from a peripheral device can be used. The oxygen saturation sensor is a known chemical and / or optical sensor that can be used to measure the oxygen saturation (SpO2) in the blood of the ventilated person as a central reference variable.

[0032] Preferably, the control device is arranged directly adjacent to the radial fan. If the control device is located directly on the radial fan, the interfaces to the sensor device and actuators of the ventilation device are advantageously minimized.

[0033] In addition to the control function, the control device can advantageously fulfil an alarm function and in particular to issue an alarm signal when a malfunction of the

[0034] The alarm signal can be set up to indicate a ventilator failure and / or a critical condition of the ventilated person. The alarm signal can, for example, include a light signal and / or a sound signal and / or a digital alarm (alarm signal transmitted via a network connection to a central monitoring computer). The alarm signal can be used, in particular, to signal to clinical staff if there is a risk of destabilization of the ventilation.

[0035] The control device contains in particular a motor controller, such as a BLDC controller, which is preferably arranged directly on the motor in order to minimize electromagnetic interference in the environment.

[0036] The control unit of the ventilator is configured to control the radial fan with the first control loop (innermost control loop), which can be used to adjust the ventilation pressure at the outlet of the radial fan. The first control loop forms a pressure control. If the radial fan has a flat characteristic curve according to a preferred variant, the ventilation pressure is proportional to the square of the rotational speed of the radial fan. The ventilation pressure has a vanishing or negligible dependence on the flow velocity, so that the first control loop preferably comprises a PI controller with two learned I levels for PIP and PEEP as setpoints.

[0037] Furthermore, the control device for controlling the radial fan is configured with the second control loop, with which at least one of a frequency of the inhalation phases, in which the inhalation pressure is generated at the outlet opening of the radial fan, and a duty cycle of the duration of the inhalation phases relative to the duration of the exhalation phases, in which the exhalation pressure is generated at the outlet opening of the radial fan, can be adjusted. The next higher control level above the first control loop is thus formed by a time control, whose setpoints for frequency (f) and duty cycle (I:E) can be set and parameterized within physiologically reasonable limits. The second control loop specifies the switching times for the pressure control in the first control loop. Preferably, the second control loop also contains an adaptation function to synchronize the operation of the radial fan with the patient's spontaneous breathing efforts.

[0038] According to a particularly preferred embodiment of the invention, the control device for controlling the radial fan is additionally equipped with a third control loop, with which target values ​​of the first and / or the second control loop can be adjusted such that the tidal volume and / or the minute volume of the ventilation are adapted to predetermined reference values ​​of the tidal volume or the minute volume. The physiologically predetermined reference values ​​are aimed for by the control with the third control loop, i.e. the tidal volume or the minute volume are set to the reference values ​​of the tidal volume or the minute volume or at least approximated thereto. The third control loop forms a further control level with which changes in the stiffness of the lung (compliance) and the airway resistance (resistance) can advantageously be responded to within predetermined, parameterizable limits.The reference variable of the third control loop is the tidal volume calculated by temporally integrating the flow during inspiration and expiration phases. The setpoint for this controller is specified by the minute volume parameter, which can be detected by the sensor device. The output of the third control loop modifies the setpoint specifications of the pressure control and the time control. This results in indirect volume-controlled ventilation, as provided for in the MMV (Mandatory Minute Volume) and Dräger AutoFlow ventilation methods, without the potentially harmful side effects of conventional direct volume control methods.

[0039] Particularly preferably, the control device is further configured to control the radial fan as a function of an output signal from an oxygen saturation sensor with a fourth control loop, with which a target value of the third control loop can be adjusted such that the oxygen saturation in the blood of the ventilated person is adapted to a predetermined oxygen saturation reference value. The oxygen saturation reference value is physiologically predetermined and is aimed for by the control with the fourth control loop, i.e. the oxygen saturation is set to the oxygen saturation reference value or at least approximated thereto. At this highest control level, the target value of the minute volume is predetermined by an i-controller, which has the oxygen saturation as a reference variable and compares it with its local target value. This advantageously closes the overall control system.

[0040] Further details and advantages of the invention are described below with reference to the accompanying drawings. The drawings show schematically in Figure 1: a perspective view of a preferred embodiment of the ventilation device according to the invention; Figure 2: side views of the ventilation device according to Figure 1 ; Figure 3: Sectional views of the ventilation device along lines 3A and 3B in Figure 2 ; Figure 4: a flow diagram of the ventilator according to preferred embodiments of the invention; and Figure 5: a flow diagram of a control of a radial fan of a ventilator.

[0041] Features of preferred embodiments of the invention are described below by way of example with reference to a configuration of the ventilator in a spherical housing, a flow diagram of the ventilator, and a flow diagram of the preferably provided control circuits. It is emphasized that the practical implementation of the invention is not limited to the examples shown, but can be modified, particularly with regard to the dimensions, shapes, materials, and design of the control circuits.

[0042] The ventilator 100 is in Figure 1 in perspective view and in the Figures 2 and 3schematically shown in side and sectional views with the radial fan 10, the first breathing line 20 (partially shown), the second breathing line 30 (partially shown), the sensor device 40, and the control device 50 in a substantially spherical housing 101. The radial fan 10 contains, in a fan housing 13, in a manner known per se, an electric motor 14 and an impeller with fan blades 15 (see Figure 3A). The electric motor 14 is, for example, a brushless direct current (BLDC) motor. The axis of rotation of the electric motor 14 defines a main axis (z-direction) of the ventilator 100. The fan housing 13 extends perpendicular to the main axis and has a central inlet opening 11 opening along the main axis and a tangential outlet opening 12 opening perpendicular to the main axis.The first end 21 of the first breathing line 20 is connected to the inlet opening 11 and the first end 31 of the second breathing line 30 is connected to the outlet opening 12.

[0043] When the radial fan 10 is in operation, ventilation air is drawn in through the inlet opening 11 and provided at the outlet opening 12 at a ventilation pressure dependent on the breathing phase. The radial fan 10 is preferably equipped with straight, radially extending fan blades 15, whereby the centripetal effect of the fan blades 15, rather than aerodynamic effects, is used to build pressure. Particularly preferably, the fan blades 15 are angled with respect to the circumferential direction of the radial fan. This reduces the effectiveness but also the operating noise of the fan. At a maximum speed of 40,000 revolutions / min determined by the operating voltage, for example, a maximum ventilation pressure of approximately 35 mbar is generated at a maximum flow of approximately 100 l / min.

[0044] The first breathing line 20 and the second breathing line 30 are each formed from a rigid or flexible conduit material and preferably each comprise a plastic tube. The second end 22 of the first breathing line 20 is connected to the breathing air conditioning device 70 and arranged to receive inhaled air (see Figure 4 ). The second end 32 of the second breathing line 30 is connected to the face mask 110 via a filter device 60 (see Figure 4 ).

[0045] The valve device 23, comprising a passive outlet valve, is provided directly at the inlet opening 11 of the radial fan 10 at the second end 22 of the first breathing line 20. The valve device 23 closes during the inhalation phases, so that inhaled air is supplied to the radial fan 10, and it opens at an increased pressure during the exhalation phases, so that exhaled air is discharged past the first breathing line 20 into the environment. The outlet valve is preferably a simple expiratory valve located directly in front of the inlet opening of the fan 11. The inlet opening of the fan 11 is thus switched between oxygen / humidification and exhalation outlet depending on the sign of the air flow flowing through the radial fan 10.

[0046] The sensor device 40 comprises a pressure sensor 41 and a flow sensor 42, with which the pressure and the flow velocity in the second breathing line 30 can be detected. The measurement is carried out at a constriction 43 in the second breathing line 30 (see Figure 4 ). The constriction 43 comprises, for example, a nozzle. The pressure sensor 41 and the flow sensor 42 are connected to the control device 50, which regulates the radial fan 10 in dependence on output signals from the sensors, as described below with reference to Figure 5 described.

[0047] The control device 50 comprises, as schematically shown in Figure 1As shown, a motor controller 51 for providing a control signal for operating the electric motor 14 and a control circuit 52 for implementing the control loops for controlling the radial fan 10. The motor controller 51, such as a BLDC controller, is preferably arranged directly on the electric motor 14 to minimize electromagnetic interference (EMI). The control circuit 52, such as an Arduino microcontroller, is preferably located directly on the radial fan 10 to control the ventilator 100 in order to minimize the interfaces to the sensors and actuators.

[0048] The ventilator 100 is further equipped with an electrical interface 102 (see Figure 1), which is configured for the connection of at least one electrical connection for power supply and data exchange and / or for a wireless connection of the ventilator 100 to an external network or control device. The interface 102 is designed, for example, for a 4-pin cable (2 pins for supply voltage, e.g., 12V, and 2 pins for a USB port) and is provided with an interface for the SpO2 sensor, an interface for a visual and / or acoustic alarm, and a Bluetooth interface for a remote control and / or a data logger, e.g., with a computer or smartphone.

[0049] The pneumatic configuration of the radial fan 10 is described below. This fan operates as a pressure generator for generating a flow-independent ventilation pressure of, for example, 5 to 30 mbar. With the radial fan 10 having straight, radially extending fan blades 15, the ventilation pressure at the outlet opening of the radial fan 10 is generally as follows: p = 1 / 2 * ρ * 2 * p i * f 2 * r a 2 − r i 2 where: ρ = air density, f = rotational speed, ra = outer diameter of the impeller, ri = inner diameter of the impeller. With a maximum speed of 40,000 rpm (670 Hz) achieved with a BLDC motor, this results in a minimum outer diameter of approximately 40 mm. In order to achieve a flow of, for example, 100 l / min, the fan blades 15 preferably have a height of approximately 4 mm on the circumference. With the fan housing 13, the radial fan 10 has a diameter of approximately 60 mm and a height of approximately 15 mm, with a mass of approximately 20 g. The dead volume of the radial fan 10 is only approximately 10 ml.

[0050] With these exemplary parameters, an average power P results according to P = 0.001 m 3 < / s * 2.500 Pa = 2.5 W. Assuming an efficiency of the ventilation device 100 of 25%, the average power consumed by the electric motor 14 is approximately 10 W to 12 W. A motor of this power class weighs approximately 10 g and has a diameter of approximately 18 mm and a length of approximately 15 mm. The form factor of the blower (diameter >> length) enables the integration of the blower, the measuring section for flow measurement and pressure measurement, the motor control and the expiratory valve into a spherical housing 101 with the size of a tennis ball and a mass of approximately 50 g. Advantageously, this achieves sizes comparable to those achieved with a Pall Ultipor 50 respiratory gas filter, which has a mass of 26 g (dry) and 35 ml dead volume.

[0051] The flow diagram according to Figure 4schematically illustrates the pneumatic and electrical configuration of the ventilator 100 with the radial blower 10, the first and second breathing lines 20, 30, the sensor device 40, the control device 50, the filter device 60, and the breathing air conditioning device 70. The pneumatic interfaces of the radial blower 10 include the inlet opening 11 with a hose connection for the air supply and with the expiration valve of the valve device 23, and the outlet opening 12, which opens to the sensor device 40 and the filter device 60. This forms the continuous bidirectional flow path (see double arrow B), along which air flows either to the face mask 110 or vice versa into the environment (arrow B).

[0052] The filter device 60 is arranged in the second breathing line 30 between the sensor device 40 and the face mask 110. The filter device 60 comprises a preferably replaceable HEPA filter 61. The HEPA filter 61 is preferably located directly on the face mask 110, so that the dead volume of the ventilation device 100 is advantageously minimized.

[0053] For humidification, temperature control, and adjustment of the oxygen content of the breathing air, the breathing air conditioning device 70 is provided at the second end 21 of the first breathing line 20. The breathing air conditioning device 70 is located outside the housing 101 of the ventilator 100 (see Figure 1). In the breathing air conditioning device 70, inhaled air from the environment, optionally enriched with oxygen from an oxygen cylinder, flows through heat exchangers from a resistance heating element and / or a Peltier element. Furthermore, the breathing air conditioning device 70 contains a humidifier that charges the inhaled air with water vapor and / or aqueous aerosol droplets.

[0054] The pressure sensor 41 and the flow sensor 42 of the sensor device 40, as well as the oxygen saturation sensor 120, are connected via signal lines (shown in dashed lines) to the control device 50, in particular the control circuit 52. The oxygen saturation sensor 120, e.g., a pulse oximeter, is coupled to the person being ventilated during operation of the ventilation device 100 to detect the oxygen saturation in the blood. The control device 50 is connected via a control line 53 to the radial fan 10, in particular its motor control 51. If an actively actuated three-way valve of the valve device 23 is provided instead of the passive expiration valve, this is also controlled by the control device 50 (see dotted control line) in order to open alternately into one of the two branches of the first breathing line 20 according to the breathing rhythm.Optionally, the breathing air conditioning device 70 can also be controlled with the control device 50 or with an external control.

[0055] The diameter of the first and second breathing lines is, for example, 15 mm. The length of the second breathing line 30 from the radial fan 10 to the filter device 60 is, for example, 30 mm. At the constriction 43, the second breathing line 30 has a diameter of, for example, 8 mm.

[0056] Deviating from Figure 4 The valve device 23 with the valve opening into the environment can be arranged on the side of the second breathing line 30, e.g., on the face mask 110 or between the sensor device 40 and the radial fan 10. In this case, the first breathing line 20 preferably has only a single branch. However, if expiration is to be pressure-controlled, the radial fan 10 must be arranged on the mask side in front of the expiration outlet.

[0057] The Figure 4The compact design of the ventilation device 100 illustrated offers the following advantages in particular. A hose system is not required, since the radial fan 10 with the sensor device 40 can be plugged directly onto the HEPA filter 61. Valves are not absolutely necessary. In particular, an external expiration valve, as is common with single-hose systems, is not required. The resting resistance of the ventilation device 100 is on the order of magnitude of that of the HEPA filter, e.g., 3 mbar*s / l. Since the pneumatic system can be heated to temperatures above 40°C within a few seconds, condensation can be effectively prevented. An air flow used for system cooling can even be used with a simple air scoop to heat the connected HEPA filter. The mechanical structure of the ventilation device 100 with the housing and the breathing lines can be easily manufactured from plastic, e.g., using 3D printing.

[0058] The ventilation pressure at the outlet opening 12 of the radial fan 10 is adjusted with the Figure 5 The control method shown is alternately set to an inspiratory pressure or an expiratory pressure, as explained below. The control method comprises four control loops I to IV, of which the first (I) and second (II) control loops are necessary for the operation of the ventilator 100, while the third (III) and fourth (IV) control loops are provided according to preferred embodiments. The control loops form a cascade in which each control loop manipulates the setpoints of the control loop of the next lower level.

[0059] Actual values ​​(reference variables) of the control loops are provided by the pressure sensor 42 for the first control loop I, the flow sensor 42 for the second control loop II, an output 54 of the control circuit 52 for the third control loop III, and the oxygen saturation sensor 120 for the fourth control loop III. Limiters designated IA to IVA are provided in each of the control loops to keep the control loops within specified limits of time and pressure parameters. In test steps IB to IVB, specified setpoints are compared with the actual values, as explained below. In steps IC to IVC, the "Δ" function calculates the change in the respective controller setpoint based on the preset parameters.

[0060] The first (innermost) control loop I comprises a pressure controller with which the ventilation pressure (inspiratory pressure IPAP and expiratory pressure) is set using predefined PIP and PEEP parameters (IA) as upper and lower limits, respectively. The upper limit PIP is selected by the attending operator, e.g., a physician, so that the lungs are not overexpanded during ventilation, and the lower limit PEEP is selected so that the alveoli do not collapse during exhalation. The PEEP parameter is preferably selected in the range 5 mbar to 15 mbar, e.g., at 8 mbar. The first control loop I is a PI controller with which the ventilation pressure is set via the speed of the radial fan 10, and whose integration constants are given by the PIP and PEEP parameters.

[0061] A healthy person requires a tidal volume of approximately 8 ml of air / (kg [body weight] * min) at rest. Generally, the patient's condition will change over time, e.g., improving during the weaning phase from ventilation or worsening, e.g., due to progressive atelectasis (alveolar closure). To prevent alveolar collapse at the end of the expiratory phase, maintenance of the minimum pressure (PEEP, positive end-expiratory pressure) is provided. Accordingly, the ventilator 100 only needs to generate varying positive pressures.

[0062] The next higher level, the second control loop II, comprises a time control whose setpoints for the inhalation frequency (f) and the inhalation / exhalation duty cycle (I:E) are set within physiologically reasonable limits (parameterizable). Together with the underlying pressure control, the BIPAP functionality is already implemented. The frequency is selected, for example, in the range from 25 min -1< to 12 min -1<. The duty cycle is selected, for example, in the range from 30% (at low frequencies) to 50% (at higher frequencies).

[0063] At the second-highest level, the third control loop III implements control of the tidal or minute volume (TV, MV) in order to respond to changes in lung stiffness and airway resistance within predefined (parameterizable) limits. The reference variable is the tidal volume calculated by temporal integration of the measured flow during inspiration and expiration phases and provided by the control circuit 52 at output 54. The setpoint for the third control loop III is specified by the minute volume parameter. The output of the third control loop III modifies the setpoint specifications of the pressure control of the first control loop I and the time control of the second control loop II.

[0064] At the highest level, the fourth control loop IV sets the target minute volume through an i-controller that uses oxygen saturation as a reference variable and compares it with its local setpoint. This closes the entire control loop. Excessively low oxygen saturation, for example, leads to a gradual increase in the target minute volume, which in turn increases the target values ​​for PIP, respiratory rate, inspiratory / expiratory ratio, and PEEP.

[0065] The limits of the ranges of all setpoints are parameterized. This means that in the absence of a reference variable or manipulated variable from a higher level, the controls of the individual control loops automatically remain within the range specified by their local parameterization. A failure of the oxygen saturation sensor 120, for example, would lead to the minute volume setpoint freezing and, if control is activated in the fourth control loop IV, would trigger a warning. If the desired minute volume cannot be achieved within the specified limits of the time control or pressure control due to, for example, excessive compliance, the system automatically remains within these limits and issues a warning.

[0066] When operating the ventilator 100, at least one of the following safety measures is preferably provided. In the event of a power failure, the behavior of the ventilator 100 transitions to that of an FFP3 mask. The maximum speed of the radial fan 10 and thus the achievable system pressure are fixed and unchangeable by the fan design, the operating voltage, and the diameter of the fan wheel. A failure of the motor control 51 cannot cause the motor to run away, and runaway as occurs with DC motors is not possible. There are no blocking valves; the inhalation and exhalation passages are always fully open and are only dynamically pressurized. The usability of non-ventilated masks is therefore guaranteed without restriction. Condensation is prevented by design after a short warm-up phase, among other things due to the lack of hoses.

[0067] There are at least two ways to estimate potential losses due to face mask leaks during NIV ventilation. First, measuring and extrapolating the flow and pressure data at the end of the inspiration phase provides an estimate of the flow caused by mask leaks at constant pressure. Second, a bidirectional flow measurement upstream of the radial fan can be provided.

[0068] In summary, the ventilator 100 advantageously has at least one of the following features. The ventilator 100 ensures that the ventilated person receives sufficient oxygen (oxygen saturation typically > 90%) and that sufficient CO2 is removed to maintain vital functions. The system is designed to record the reference variable oxygen saturation (SpO2). Additional oxygen can be supplied. The ventilator 100 can autonomously compensate for changes in the lung condition of the ventilated person by changing the tidal or minute volume, within physiologically reasonable limits. The ventilator 100 can signal to clinical staff through acoustic, visual, and / or digital alarms when there is a risk of destabilizing the therapy.

[0069] The features of the invention disclosed in the above description, the drawings and the claims may be important both individually and in combination or sub-combination for the realization of the invention in its various forms.

Claims

1. A ventilator device (100) configured for non-invasive ventilation of a person, comprising - a radial blower (10) having an inlet opening (11) and an outlet opening (12), wherein the radial blower (10) is configured to receive ventilation air at the inlet opening (11) and to provide the ventilation air with an adjustable ventilation pressure at the outlet opening (12), - a first ventilation duct (20) having a first end (21), connected to the inlet opening (11) of the radial blower (10), and having a second end (22), arranged to receive inhalation air, - a second ventilation duct (30) having a first end (31), connected to the outlet opening (12) of the radial blower (10), and having a second end (32), configured for coupling to a breathing mask (110), wherein the second ventilation duct (30) is equipped with a sensor device (40), by which at least one flow parameter in the second ventilation duct (30) can be measured, and - a control device (50) configured to control the radial blower (10) as a function of at least one output signal from the sensor device (40), wherein - the radial blower (10) and the second ventilation duct (30) form a continuous bidirectional flow path, wherein the adjustable ventilation pressure at the outlet opening (12) of the radial blower (10) comprises an inhalation pressure or an exhalation pressure, equal to or less than the inhalation pressure, - the second ventilation duct (30) is equipped with a filter device (60), arranged for air flow filtering, and - the control device (50) is, for controlling the radial blower (10), configured with a first control loop (I), by which the ventilation pressure at the outlet opening (12) of the radial blower (10) can be adjusted, characterized in that - the control device (50) is, for controlling the radial blower (10), configured with a second control loop (II), by which at least one of a frequency of inhalation phases, in which the inhalation pressure is formed at the outlet opening (12) of the radial blower (10), and a duty cycle of the duration of the inhalation phases relative to the duration of exhalation phases in which the exhalation pressure is formed at the outlet opening (12) of the radial blower (10), can be set, wherein an actual value of the second control loop is supplied by a flow sensor (42).

2. The ventilator device (100) according to claim 1, wherein - the flow path between the second end (32) of the second ventilation duct (30) and the inlet opening (11) of the radial blower (10) is free of valves.

3. The ventilator device (100) according to any one of the preceding claims, wherein - the first ventilation duct (20) between the inlet opening (11) of the radial blower (10) and the second end (22) of the first ventilation duct (20) comprises a valve device (23), in particular a passive outlet valve, arranged as an expiratory outlet for discharging exhalation air.

4. The ventilator device (100) according to any one of the preceding claims, wherein - the second end (22) of the first ventilation duct (20) opens into an environment of the ventilator device (100) and / or is adapted for coupling to a breathing air reservoir (300).

5. The ventilator device (100) according to any one of the preceding claims, wherein - a breathing air conditioning device (70) coupled to the second end of the first ventilation duct (20).

6. The ventilator device (100) according to claim 5, wherein - the breathing air conditioning device (70) is arranged to adjust at least one of the parameters humidity, temperature, and oxygen content of the inhalation air.

7. The ventilator device (100) according to claim 6, wherein - the breathing air conditioning device (70) comprises a tempering device (71) configured to temper the ventilator device (100), in particular the second ventilation duct (30).

8. The ventilator device (100) according to any one of the preceding claims, having at least one of the features - the filter device (60) comprises a HEPA filter, and - the filter device (60) comprises a plug-in connection with the radial blower (10) and / or the second ventilation duct (30).

9. The ventilator device (100) according to any one of the preceding claims, having at least one of the features - the control device (50) is equipped with an interface for receiving an output signal from a oxygen saturation sensor, - the control device (50) is arranged directly adjacent to the radial blower (10), and - the control device (50) is configured to output an alarm signal when a malfunction of the ventilator device and / or a critical condition of the ventilated person is detected.

10. The ventilator device (100) according to any one of the preceding claims, wherein - the control device (50) is, for controlling the radial blower (10), configured with a third control loop (III), by which setpoint variables of the first and / or the second control loop (I, II) can be set such that at least one of the parameters tidal volume and minute volume of the ventilation are adapted to predetermined volume reference variables of the tidal volume or the minute volume.

11. The ventilator device (100) according to claim 10, wherein - the control device (50) is, for controlling the radial blower (10), configured, as a function of an output signal of an oxygen saturation sensor, with a fourth control loop (IV), by which a setpoint variable of the third control loop (III) can be set such that an oxygen saturation in the blood of the ventilated person is adapted to a predetermined oxygen saturation reference variable.