DE102022002797A1 - Dosing device for adding at least one pharmaceutically active substance to a breathing gas provided extracorporeally, device for providing a breathing gas with such a dosing device and method - Google Patents

Abstract

In order to improve the effectiveness of adding oxygen to a mechanically provided breathing gas and to reduce oxygen consumption during use, a metering device for adding at least one pharmaceutically active substance to an extracorporeally provided breathing gas is proposed, in which the metering device (10) has at least one metering valve (11) and has at least one gas flow control device (12), and a controller (13) for controlling the at least one metering valve (11) and the at least one gas flow control device (12), the gas flow control device (12) having at least one inlet connection for connection to a breathing gas source (2), has a patient-side outlet and a ventilation outlet (20), the control (13) having at least one connection for at least one sensor device (17), as well as a method and a ventilator.

Description

The invention relates to a metering device for adding at least one pharmaceutically active substance to a breathing gas provided extracorporeally and to a device for providing a breathing gas with such a metering device and a method for operation.

Devices for providing a breathing gas with at least one breathing gas source, a control for the breathing gas flow and a gas delivery device for the controlled breathing gas flow are known in the prior art. The gas delivery device can be connected to at least one oxygen source. Such devices are known for both outpatient emergency use and inpatient clinical use.

In stationary clinical use, the breathing gas source is usually a central compressed air or oxygen supply with appropriate connection points in the treatment rooms and patient rooms. The ventilators themselves are usually movable on rollers and have corresponding connecting cables with which the devices can be connected to the central breathing gas source. From the FR 2159735 A5 Such a portable device with a fan is known that is supposed to be operated with mains power.

When using such devices for outpatient emergency use, simpler devices are usually used. Common compressed gas bottles for compressed air and/or oxygen serve as the breathing gas source. The gas contained in the compressed gas bottles is usually filled under an excess pressure of around 200 bar. In order to have a sufficient supply of breathing gas at least for transport to a hospital, such a compressed gas cylinder with a filling volume of at least 10 l is required. Due to the bulky dimensions and in particular the high weight of such a filled compressed gas cylinder, such a device for outpatient emergency use is only practically possible for use in vehicles or, for example, a helicopter. In stationary use, a mixture of compressed air and oxygen is usually used as breathing gas. Since oxygen is practically always supplied with such a device in outpatient emergency use, two compressed gas bottles are required as a breathing gas source, namely a compressed air bottle and an oxygen bottle, which leads to a considerable weight to be transported. In order to keep the weight lower, it is also known to carry only one oxygen bottle and to mix ambient air with the oxygen from the compressed gas bottle by appropriately designing flow paths via a Venturi nozzle and to use it as breathing gas. Furthermore, the known devices also have a mechanical or electronic control, via which the breathing gas flow can be controlled in accordance with the required ventilation frequency.

A device of the type mentioned at the beginning is, for example, from WO 87/06142 A1 known. The device disclosed there includes a monitor for monitoring a patient's breathing activity. Immediately at the beginning of each inhalation, a volume pulse of oxygen is delivered to the patient. If the patient is breathing irregularly or cannot breathe spontaneously at all, the device provides a continuous flow of oxygen. From the EP 324 275 A1 a ventilator is known that includes breathing synchronization. The device is intended for use during respiratory arrest, whereby a breathing gas can be delivered from the ventilator to the patient at selected times after inspiration or exhalation begins. The synchronization device is connected to a monitor for monitoring breathing. The monitor records body impedance, electromyograms, chest movements and the like.

A blower-operated ventilator is out of the US 4,957,107 and WO 89/10768 A1 known. In one embodiment described there, the addition of oxygen is provided. The addition is accomplished via several valves that are operated by a controller. The added oxygen is mixed with the breathing air provided by the fan in a mixing chamber. The oxygen concentration in the mixing chamber is recorded via a galvanic sensor. The measurement signal is digitized, processed in a microcontroller and compared with a specified reference value. An analog signal is generated from the difference value, which is used to control the oxygen valve until the difference between the measured value and the reference value is zero.

From the US 4,587,967 A ventilator is known in which the breathing air is provided via a piston compressor. The addition of oxygen is also regulated by measuring an oxygen concentration in a mixing chamber.

In the US 4,127,121 is a closed ventilation system described with a CO2 scrubber. The addition of oxygen is also regulated here by measuring the oxygen concentration in the mixed breathing gas. Anesthesia machines use a closed ventilation system to prevent anesthetic gas from escaping. The exhaled carbon dioxide is filtered out of the system using soda lime. With such devices you can This means that you can also be ventilated with, for example, 0.3 liters of oxygen per minute, which corresponds to the approximate oxygen consumption of an adult at rest. However, such ventilation is only carried out in patients whose airways are sealed via a tube or a laryngeal mask.

At the one in the WO 96/11717 A1 In the portable ventilator described, the breathing frequency is achieved by cyclically controlling the fan that provides the breathing air.

A compressed gas-operated blower from an installation typically found in hospitals is from the WO 87/01599 A1 removable. Highly compressed oxygen gas should preferably serve as an energy source.

From the DE 196 26924 C2 A ventilator is known in which the breathing gas source comprises a motor-driven fan. The proposed design of the device means that it is no longer necessary to carry large compressed gas bottles. For the medically necessary oxygen requirement, in a device according to the invention, a 1 liter bottle is sufficient to supply a patient for approximately 3 hours. Due to the small, handy 1 liter bottle, it is therefore possible to operate such a device on a mobile basis, especially for outpatient use; in particular, permanent installation in vehicles is no longer necessary. Using an electric motor, such a device can be operated practically anywhere where there is the possibility of a power supply. If appropriately equipped with accumulators, it is even possible to design a device according to the invention in such a way that the device can function completely without an external energy supply for a while.

After EP 0 925 085 A1 In order to optimally coordinate the components and, for example, to compensate for losses due to leaks, for example in a breathing mask, it is proposed to record a measuring device for determining at least one parameter of the gas being delivered, with the at least one measuring device influencing the control. In the WO 98/01176 A1 It is proposed to provide a gas flow measuring device and/or a gas pressure measuring device. Optionally, it is proposed to provide a certain time delay for the addition of oxygen from the oxygen source. The time delay can be set on the device by a doctor. The delay time can be determined, for example, as the average time to reach a certain percentage of a peak value over a preselected number of breathing cycles or depending on the condition, compliance and functional residual capacity of the lung.

Numerous proposals are known for controlling the breathing gas flow on the consumer side independently of a substantially uniform gas flow generation, in particular by a blower. From the DE 34 13 037 C2 For example, a control device for a portable ventilator is known, in which the breathing gas flow generated by the blower is diverted into a gas reservoir during the patient's expiration phase. From the DE 34 22 066 C2 a valve device is known for alternately providing a breathing gas with positive or negative pressure from a compressed air source.

These known systems work satisfactorily as long as medical professionals are available to operate them or the patient is being treated with them in a hospital.

Depending on the type and severity of the disease, ventilation therapy is carried out with supportive to completely mechanical inhalation and prevention of complete exhalation. If the respiratory pump is exhausted, the respiratory muscles are relieved during inhalation or, in the event of gas exchange disorders, the further loss of gas exchange surface is counteracted by preventing complete exhalation. As the severity of the lung damage increases, not only the pressure to prevent complete exhalation but also the oxygen content during inhalation increases. The significantly increased work of breathing that is then required can no longer be compensated for by the respiratory muscles. As exhaustion increases, respiratory insufficiency develops and breathing becomes faster and shallower. Now both inhalation and exhalation must be treated combined by ventilation.

If complete exhalation is not prevented sufficiently and in a timely manner during the course of the disease, very pronounced gas exchange disorders arise in the context of ARDS or COVID-19 viral pneumonia. Gas exchange surface is lost due to collapsed lung areas because due to increased permeability between blood capillaries and alveoli and/or due to viral infection of the lung cells, the surface-active substance “surfactant” can no longer stabilize the alveoli during exhalation.

However, areas of the lung that have collapsed and are therefore not ventilated continue to be supplied with blood: less oxygen is absorbed and, despite the administration, large amounts of oxygen are received A life-threatening lack of oxygen develops. The first people to describe ARDS recognized this in 1967 and they also recognized how they could use ventilation to counteract collapse during exhalation. Since then, attempts have been made to prevent the collapse of damaged areas of the lungs by providing positive ventilation pressure during exhalation. This is called “positive end-expiratory pressure” or PEEP. If you only breathe spontaneously during inhalation at a continuous airway pressure without additional ventilation pressure, this is called “continuous positive airway pressure” or CPAP.

If high oxygen concentrations of over 50% are inhaled, especially when collapsed areas of the lung are insufficiently opened, this in turn results in serious side effects and complications: Sustained high oxygen concentrations are not only toxic for the lung tissue. Particularly areas of the lungs that are less reached by ventilation collapse more quickly when oxygen concentrations are high. This is called resorption atelectasis: the build-up of the lung-stabilizing ventilation pressure during exhalation - i.e. PEEP or CPAP - no longer works efficiently at these high oxygen concentrations: The Oxygen absorption into the bloodstream causes the pressure in these lung areas to drop rapidly, so that sections in particular that are poorly ventilated collapse and can therefore no longer participate in gas exchange.

Ventilation can support your own spontaneous breathing in a synchronized manner or can be carried out in a controlled manner independent of your own breathing. During controlled ventilation, the breathing frequency, the tidal volume or the ventilation pressure are controlled and the breathing time ratio between inhalation and exhalation is also specified. In addition, there are forms of ventilation that allow you to breathe independently of ventilation and numerous mixed forms. The airway is secured with a tube if there are no protective reflexes, for example during anesthesia or coma. This is intended to protect the airways from aspiration, i.e. the entry of stomach contents into the trachea, which can also cause ARDS. Intubation is also carried out if NIV is no longer tolerated by the patient or is unsuccessful: As soon as high ventilation pressures and high oxygen proportions are required due to increasing lung damage, above a certain limit, which can be very controversial as mentioned above, NIV - positive pressure administration can become unsafe and even dangerous be: Even the slipping of a mask, the removal of a helmet or a necessary interruption of the NIV for intubation can then lead to a life-threatening lack of oxygen.

The so-called “supraglottic airways” or “SGA” represent an intermediate stage of airway protection, such as the laryngeal mask or the laryngeal tube, which are used during anesthesia or emergencies: Here, a tube is not inserted through the glottis into the trachea, but the larynx from the outside enclosed and sealed so that ventilation can take place. Depending on how the airway is secured, this is referred to as “invasive” or “non-invasive ventilation”: If the airway is secured via a tube and ventilated through it, this is referred to as “invasive ventilation”. Ventilation without a tube is referred to as “non-invasive ventilation” or “NIV”. With negative pressure ventilation, NIV can be carried out without airway access, while with positive pressure ventilation there must always be airway access: NIV can be carried out with positive pressures via a respiratory helmet or with a mask that covers the entire face, mouth and nose or just the nose.

One of the main problems of current intensive care therapy is invasive positive pressure ventilation via the trachea tube or tube: Even the so-called “lung-protective ventilation” not only damages the already damaged lungs and respiratory muscles, but also other organ systems. It also sets off a whole chain reaction of life-threatening complications: Mainly because of the tube, up to half of patients receiving invasive ventilation also develop pneumonia, which not only further damages the lungs, but also other organ systems. The tube in the trachea also activates pronounced protective reflexes, which requires analgesic sedation (“artificial coma”) for shielding and dampening. This results in numerous side effects and other serious complications. The respiratory muscles quickly become significantly weakened and sedation-related overhangs often occur. This increases the duration of ventilation and often causes ventilation-related complications. In addition, especially in combination with positive pressure ventilation, sedation can significantly impair circulatory functions, so that medication to support circulation must be administered continuously. These so-called catecholamines, in turn, reduce organ blood flow and can accelerate the failure of several organ systems. COVID-19 patients requiring ventilation are often treated in the prone position, which means they require particularly deep sedation.

Ventilation can also take place without a tube. However, it can then be difficult to adapt this so-called non-invasive ventilation (NIV) to the severity of the lung damage efficiently enough to avoid collapsing areas of the lungs and increasing respiratory insufficiency. The increased respiratory drive that then occurs with increased and deepened breathing also damages the lungs. This is called patient-self-inflicted injury or P-SILI.

Such non-invasive ventilation (NIV) is a prerequisite for ventilation of patients outside of intensive care. In particular, this could counteract overloading of intensive care units specifically by COVID-19 patients.

Current NIV devices are used primarily in the treatment of sleep apnea to keep the upper airways open and in the treatment of chronic lung diseases to reduce the work of breathing (see above). However, the oxygen content in these turbine-driven NIV devices can only be slightly increased by supplying oxygen: by sucking in from the ambient air, the turbines generate a very high gas flow in order to enable appropriate ventilation pressures even with respiratory masks that are not tightly sealed. With the resulting peak flows of over 200 liters per minute, even with high oxygen supply, the dilution effect means that only relatively low oxygen concentrations are achieved in the inhaled air, which are not sufficient for effective therapy of progressive lung damage.

A special form of respiratory therapy is the so-called “nasal high-flow oxygen therapy”, which is also recommended for COVID-19 despite the pronounced aerosol formation. It is carried out with a high flow via a nasal cannula or mask. While with conventional oxygen therapy up to 15 liters per minute are administered via a nasal probe or mask, with nasal high-flow oxygen therapy up to 60 liters per minute are administered.

From the DE 34 12 118 A1 is a valve device known as a breathing phase regulator for a device for the non-invasive supply of oxygen to a patient via an inhaler, such as a nasal probe, from an oxygen source using a pressure and quantity regulator, in which the oxygen supply is to be interrupted during the patient's exhalation phase. This should be done by recording the dynamic pressure of the oxygen supply in the nasal cannula using a pressure can.

Electrical stimulation of the vagus nerve is recommended WO 2006079484 A1 known from the previously published prior art. For this purpose, it is suggested to invasively wrap a nerve with a conductor as an electrode. The device for generating current pulses is implanted under the skin in the left shoulder area. The vagus nerve stimulator can later be programmed externally using an electromagnetic field. Electrical vagus nerve stimulation stimulates the brain in various areas. The device is designed and suitable for stimulating the vagus nerve in the area of the external auditory canal and/or the auricle. In addition to its effectiveness in epilepsy, the stimulation treatment also leads to psychological effects, e.g. B. antidepressant effects. The control unit is preferably arranged in the housing. However, it can also be provided that the control unit can be removed from the housing and is connected to the electrodes. The proposed invention is intended to make transcutaneous stimulation of the vagus nerve possible, in particular for the treatment of neuropsychiatric disorders, with a stimulation electrode placed in or on the external auditory canal for transcutaneous stimulation of the auricular artery of the vagus nerve and a reference electrode placed in or on the external auditory canal are preferably connected to a control unit that is worn on or behind the ear. The EP 1 393 773 A1 describes an external nerve stimulator of the phrenic nerve using an oesophageal electrode. The EP 0 962 234 A1 describes a device for electrical nerve stimulation, where placement of the electrodes is not disclosed. The EP 0 645 162 B describes a stimulation device for stimulating muscles and nerves, which includes a function generator for generating a waveform with a sequence of pulses. It is particularly intended for pain therapy.

The high number of patients requiring oxygen therapy as a result of the COVID-19 pandemic has led to supply shortages of medical oxygen worldwide. Particularly in countries with a less well-developed hospital infrastructure, the demand for medical oxygen in compressed gas cylinders significantly exceeds the capacities of the gas providers, with the result that many patients cannot be treated and suffocate.

The invention is therefore based on the object of providing improved devices for providing a breathing gas.

This task is solved according to the invention by a metering device for adding at least a pharmaceutically active substance to a breathing gas provided extracorporeally, the metering device having at least one metering valve and at least one gas flow control device, as well as a controller for controlling the at least one metering valve and the at least one gas flow control device, the gas flow control device having at least one inlet connection for connection to a breathing gas source patient-side outlet and a vent outlet, and wherein the control has at least one connection for at least one sensor device.

The object is further achieved by a method for operating a metering device for adding at least one pharmaceutically active substance to an extracorporeally provided breathing gas with the following steps: detecting at least one measurement signal from at least one sensor device, converting the at least one measurement signal into a parameter value, controlling a first metering valve at a predetermined time after detecting a predetermined size for the one parameter value, so that the metering of a certain amount of the at least one pharmaceutically active substance takes place, and activating a gas flow control device for the breathing gas at a predetermined time depending on the control of the first metering valve, so that an amount of gas corresponding to the amount of gas of the pharmaceutically active substance metered into the breathing gas through the first metering valve is vented into the environment, as well as a ventilator.

According to the invention, the at least one pharmaceutically active substance preferably contains oxygen and/or surfactant and/or a drug. In the typical applications for the use of the invention, the pharmaceutically active substance will contain gaseous oxygen in a concentration above that of the ambient air.

With the design of a dosing device according to the invention, the method for operating it and a ventilator equipped with it, the effectiveness of the addition of oxygen to a mechanically provided breathing gas can be improved and thereby the oxygen consumption can be significantly reduced. The necessary oxygen requirement reduced by the invention can therefore be obtained directly from the ambient air on site using commercially available oxygen concentrators, even for COVID-19 patients requiring ventilation, so that the patient can be treated independently of the supply of medical oxygen in compressed gas bottles.

With the invention, successful self-directed, non-invasive intensive treatment (self-directed intensive respiratory care or SDIRC) can be carried out for the first time in combination with a ventilation pressure generated independently of oxygen. This intensive breathing therapy can even be carried out in cases of severe lung damage, without having to be carried out in an intensive care unit or hospital. This is achieved by the fact that the airway or ventilation pressure is generated exclusively by turbines using the ambient air, as with a NIV device. The stabilizing effect of increased airway pressure can preserve gas exchange area during spontaneous breathing. Collapsed areas of the lung can be reopened by taking deep breaths (“Open Lung Concept”). A sufficiently and persistently available gas exchange surface in the ventilated lung is the prerequisite for actually achieving improved oxygen absorption with an increased oxygen supply during inhalation.

In contrast to intensive care ventilators or CPAP or NIV devices, with the method presented here, the oxygen supply occurs separately and independently of the turbine-driven gas flow that generates the CPAP or ventilation pressure. This independent oxygen supply is so effective that practically the entire amount of oxygen can be absorbed. This means that you only have to give as much oxygen as is actually needed. Only 30 - 50 ml of oxygen are supplied synchronously with breathing at the beginning of inhalation. Through the subsequent breathing air, this small amount of oxygen reaches all areas of the lungs evenly and immediately into the area of the alveoli, where the oxygen can be absorbed directly into the pulmonary circulation and the circulation via the open gas exchange surface. This precisely synchronized oxygen administration is so efficient that even with severe lung damage, in combination with CPAP, less than one liter of oxygen is required per minute.

In principle, it is known to add oxygen to a breathing gas separately and in time relation to the beginning of an inhalation phase, such as in WO 98/01176 A1 described. In comparison, tests with a dosing device according to the invention resulted in a yield improved by 15.5%. With the same volume flows of breathing gas used from a conventional CPAP ventilator and a conventional oxygen concentrator, the metering device according to the invention resulted in a 15.5% increased oxygen concentration in the gas stream delivered to the patient. The amount of oxygen fed in can be reduced accordingly to achieve a specified oxygen concentration.

The efficiency of this special form of breathing-synchronous oxygen administration can only be achieved by conventional CPAP or ventilation therapy through a very high oxygen concentration of 60 to 70% when inhaling. In a study of COVID-19 patients with severe lung damage, less than 60% oxygen was usually supplied during inhalation. Adequate oxygen supply even to these patients would be easily possible with the SDIRC concept.

However, the new method eliminates the pronounced side effects and complications that occur with standard therapy with very high oxygen concentrations: As mentioned above under “Fundamentals of ventilation”, sustained high oxygen concentrations not only have a toxic effect on the lungs, but also promote resorption atelectasis due to a drop in pressure , i.e. the collapse of areas of the lung that are less reached by ventilation.

With the therapy currently used, 90% of the oxygen administered is released into the environment and is therefore lost. In other words, the same amount of oxygen can treat 10 times more patients. In addition, the high efficiency opens up new decentralized treatment options, as such a small amount of oxygen can now be easily produced yourself. Oxygen concentrators have been part of standard therapy for a very long time and are used particularly in the treatment of chronic lung diseases. There are even battery-powered mobile devices that are capable of extracting at least one liter of oxygen per minute from the surrounding air. This means that it is technically possible to carry out sensible, intensive breathing therapy using the simplest technology, even if there is no intensive care capacity or a lack of oxygen, even if there is severe lung damage. Even if there is a lack of qualified specialist staff, this therapy can still be used successfully. Standard parameters such as peripheral oxygen saturation and respiratory rate are recorded. According to the measured values, after prior instruction and training and/or algorithm-controlled and/or telemetric support, patients can treat themselves efficiently with intensive breathing therapy. This self-controlled, non-invasive, intensive breathing therapy can close an important gap in care that currently exists not only in developing and emerging countries.

The SDIRC concept allows non-invasive treatment strategies to be successfully applied at a very early stage of the disease, even in cases of severe lung damage. If spontaneous breathing is maintained, the very serious complications of invasive ventilation therapy with additional lung damage can also be averted: early and effective stabilization of the lungs also relieves the respiratory muscles and counteracts additional, self-inflicted lung damage through increased respiratory drive. What is crucial is the timely use of the SDIRC concept - before a very advanced stage of lung damage is reached. If the condition worsens anyway, more invasive therapy can still be carried out if resources and capacities are available.

Another particular advantage of the dosing device according to the invention is that it can be used as an additional device with any existing non-closed ventilation system, as well as being integrated into a ventilator or assembled with an oxygen concentrator.

In a preferred embodiment of the invention, the at least one sensor device comprises an electrical sensor for recording neuronal signals. If spontaneous breathing is maintained, the beginning of an inhalation phase can be detected particularly precisely.

Alternatively or additionally, the dosing device according to the invention comprises an electrical sensor for detecting an expansion of a patient's chest. The beginning of an inhalation phase can also be easily detected by detecting the expansion of the chest, but detection does not depend on whether the patient is breathing spontaneously. A combination of both sensor technologies is recommended to obtain a redundant signal. This makes it possible not only to detect a failure of spontaneous breathing by comparing the signals from the two sensors, but also a failure of one of the sensors or a connection to it. For example, a fallen electrode or a broken cable can be easily detected.

The gas flow control device preferably comprises a directional valve, in particular a 3/2-way valve. This allows a particularly compact and cost-effective design of a metering device according to the invention to be achieved.

In a further preferred embodiment of the invention there is also a device for emitting a signal for electrical or electromagnetic stimulation of the phrenic nerve seen. This can trigger muscle work for the patient's own breathing, even if spontaneous breathing is absent or unreliable. Compared to purely mechanical ventilation, the major advantage is that the respiratory muscles do not degenerate due to inactivity. This prevents one of the biggest side effects of artificial ventilation. Due to the patient's own breathing work, the requirements for securing the airway and also for tightness are lower. Intubation can often be avoided. The signal can already be fed back within the device to the at least one connection for the at least one sensor device, since the start of an inhalation phase is inevitably determined by the signal.

Preferably, the method according to the invention is further characterized in that the metering of a certain amount of the at least one pharmaceutically active substance to the breathing gas takes place at a predetermined time after detecting a predetermined value for the at least one parameter. alternatively, the metering of a certain amount of pharmaceutically active substance takes place at a certain point in time in relation to the beginning of an inhalation phase or an electrical or electromagnetic stimulation. This allows the effectiveness of the addition of a pharmaceutically active substance to be improved, as already described above.

A first metering valve is expediently controlled to meter out a certain amount of pharmaceutically active substance for a predetermined period of time. As a result, the control can take place directly from a digital signal from the control of the metering device without the need for a previous digital/analog conversion and a separate analog driver circuit for the at least one metering valve.

It is particularly advantageous if the metering of a certain amount of pharmaceutically active substance takes place in one or more pulses, in particular if a predetermined amount of pharmaceutically active substance is metered in with each pulse. Thanks to the pulsed metering of the pharmaceutically active substance, the amount added can be easily adjusted by the duration and number of pulses. If a predetermined amount of pharmaceutically active substance is added with each pulse, the dosage can simply be carried out step by step over the number of pulses according to the instructions given by the practitioner.

In particular when using a source for the pharmaceutically active substance with an unsteady substance concentration, it can be further advantageous if the control of a first metering valve for metering a certain amount of pharmaceutically active substance and the control of a gas flow control device for the breathing gas depending on the concentration of the pharmaceutically active substance Substance and / or depending on the volume flow downstream of the metering valve is regulated.

The invention can be implemented particularly well in the form of a ventilator with a metering device according to the invention for carrying out the method according to the invention.

• 1 eine schematische Darstellung einer Anordnung eines gebläsebetriebenen Beatmungsgeräts mit einer Zudosierung von Sauerstoff, nach dem Stand der Technik; und
• 2 eine schematische Darstellung einer Anordnung eines gebläsebetriebenen Beatmungsgeräts mit einer erfindungsgemäßen Dosiereinrichtung.

The invention will be explained in more detail below using an exemplary embodiment with reference to the accompanying drawings. Show it:

• 1 a schematic representation of an arrangement of a fan-operated ventilator with an addition of oxygen, according to the prior art; and
• 2 a schematic representation of an arrangement of a fan-operated ventilator with a metering device according to the invention.

1 shows an arrangement 1 of a fan-operated ventilator with a mixing valve 3 as a device for metering in oxygen according to the prior art in a schematic representation. The same or comparable parts of the arrangement with the present invention are each provided with the same reference numerals. A conventional blower-operated CPAP ventilator 2 serves as the breathing gas source. The CPAP ventilator 2 usually includes an integrated control for setting a volume flow and the breathing gas pressure specified by the practitioner. The ventilator 2 is connected to the mixing valve 3 via a connecting line 4. An oxygen source 5, for example a compressed gas bottle, is also connected to the mixing valve 3.

Furthermore, the mixing valve 3 is connected to a patient line 6, at the patient end of which there is a ventilation device, here a ventilation mask 7. A flow meter 8 is looped into the patient line 6. This is electrically connected to a controller 9. By forming the difference between the measured value from the flow meter 8 and the flow meter integrated into the CPAP ventilator 2, the actual value for regulating the addition of oxygen to control the mixing valve 3 is formed in the controller 9.

In 2 an arrangement 1 of a fan-operated ventilator with a metering device according to the invention, designated overall by 10, is shown schematically. A conventional blower-operated CPAP ventilator 2 serves as the breathing gas source. The CPAP ventilator 2 usually includes an integrated control for setting a volume flow and the breathing gas pressure specified by the practitioner. Another common compressed gas source can also be used as the breathing gas source.

The CPAP ventilator 2 is connected to a metering device 10 according to the invention via an inlet line 14. The metering device 10 has at least one metering valve 11 and at least one gas flow control device, here in the form of a 3/2-way valve 12. Furthermore, the metering device 10 also includes a controller 13 for controlling the at least one metering valve 11 and the directional control valve 12.

The directional control valve 12 has an inlet connection for connection to the CPAP ventilator 2 via the inlet line 14. Furthermore, the directional control valve 12 has an outlet on the patient side for connecting an intermediate line 15 for connection to the metering valve 11. The directional control valve 12 also has a vent outlet 20, via which part of the gas flow conveyed via the inlet line 14 can be vented into the environment. A silencer 19 or filter is preferably arranged on the ventilation outlet 20 to reduce the blow-off noise during the ventilation process. Furthermore, an integrated filter material can be used to prevent pathogens from the ambient air from penetrating into the flow paths leading to the breathing air via the ventilation outlet 20 (CPAP ventilator 2, inlet line 14, directional control valve 12, intermediate line 15, metering valve 11, patient line 6, ventilation mask 7).

In the embodiment shown, a conventional patient line 6 is connected to the metering valve 11, via which a patient can be ventilated using the ventilation mask 7. The metering valve 11 can expediently be assembled with the directional control valve 12 in order to make the metering device 10 more compact, so that a separate intermediate line 15 can be omitted. The metering valve 11 is also connected to the patient line 6, at the patient end of which there is a ventilation device, here a ventilation mask 7. A conventional flow meter 8 can be looped into the patient line 6, for example if the gas flow delivered to the patient needs to be monitored separately for regulatory reasons. Instead of or in addition to the flow meter 8, a measuring device 21 for the concentration of a pharmaceutically active substance, for example the oxygen concentration, can also be arranged.

The metering valve 11 is also connected to a source of a pharmaceutically active substance, here an oxygen concentrator 16. Gaseous oxygen will be the most common application of a pharmaceutically active substance when using a metering device 10 according to the invention. The pharmaceutically active substance can also alternatively or additionally contain, in particular, surfactant and/or a drug. For the application of surfactant or a drug, the metering valve 11 can also have a built-in nebulizer, for example to add a drug in the form of an aerosol to the breathing gas to be delivered to the patient, e.g. B. together with the oxygen.

The controller 13 has at least one connection for at least one sensor device 17. The sensor device 17 can, for example, be a commercially available strain sensor for detecting a strain in a patient's chest and/or a sensor for recording neural signals. Both types of sensors are suitable for detecting the beginning of the patient's inhalation phase, with a strain sensor also detecting inhalation forced by the ventilator. A combination of sensors has advantages in terms of redundancy in detecting the start of the inhalation phase and also enables failure detection with regard to a sensor or a patient's spontaneous breathing.

The controller 13 further comprises a device for emitting a signal for electrical or electromagnetic stimulation of the phrenic nerve in the form of a stimulator 18. This can be a puncture electrode for electrical stimulation of the nerve or preferably a coil arrangement, for example in the form of a neck cuff, for electromagnetic stimulation of the Nervous. This makes it possible to trigger breathing activity via the breathing pump even if there is no spontaneous breathing, which means that the patient's breathing muscles remain active. Furthermore, even if spontaneous breathing stops, intubation to secure the airway, which has significant side effects, can usually be dispensed with.

The signal sent to the stimulator 18 to stimulate the nerve is expediently fed back to a connection for a sensor device, since the signal also marks the beginning of an inhalation phase of the patient.

The controller 13 is connected to the stimulator 18, sensor device 17, flow meter 8, if present, concentration sensor 21, expediently the oxygen concentrator 16, metering valve 11 and directional control valve 12 via connecting lines for obtaining measured or status values, operating parameters and/or for emitting control signals . If available, an interface connection to the CPAP ventilator 2 can also be provided.

A metering device 10 according to the invention can be operated using rechargeable batteries; suitable mains power supplies and/or on-board power supplies for use in vehicles, airplanes or ships can be provided.

The operation of a dosing device 10 according to the invention for adding at least one pharmaceutically active substance to a breathing gas provided extracorporeally includes the following steps: detecting at least one measurement signal from at least one sensor device 17, converting the at least one measurement signal into at least one parameter value, preferably the beginning of an inhalation phase of the patient, Activating a first metering valve 11 at a predetermined time after detecting a predetermined size for a parameter value, here the start of an inhalation phase, so that the metering of a certain amount of the at least one pharmaceutically active substance takes place, and activating the gas flow control device (directional valve 12) for the breathing gas at a predetermined time depending on the control of the first metering valve 11, so that an amount of gas with the pharmaceutically active substance corresponding to the amount of gas metered into the breathing gas through the first metering valve 11 is vented into the environment.

Preferably, a first metering valve 11 is activated to meter out a certain amount of pharmaceutically active substance for a predetermined period of time. The amount of pharmaceutically active substance can be adjusted over the duration of such a pulse. However, it can also be expedient if a fixed, predetermined amount of pharmaceutically active substance is added with each pulse and the total amount added is adjusted based on the number of pulses. This allows the calibration effort for reliable operation of the dosing device 10 to be minimized while at the same time providing a wide range of applications for the practitioner.

Since, for example, battery-operated, commercially available oxygen concentrators 16 deliver a gas stream with a non-constant oxygen concentration when the battery charge decreases and/or fluctuating ambient temperatures, it is further expedient to determine the addition of the oxygen-enriched gas stream through the metering valve 11 and, accordingly, the amount of gas vented into the environment by the directional valve 12 as a function is regulated by the concentration of the pharmaceutically active substance detected by the concentration sensor 21 and/or depending on the volume flow detected by the flow meter 8 downstream of the metering valve in the patient line 6. Of course, the same applies to the addition of other pharmaceutically active substances.

QUOTES INCLUDED IN THE DESCRIPTION

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Cited patent literature

• FR 2159735 A5 [0003]
• WO 8706142 A1 [0005]
• EP 324275 A1 [0005]
• US 4957107 [0006]
• WO 8910768 A1 [0006]
• US 4587967 [0007]
• US 4127121 [0008]
• WO 9611717 A1 [0009]
• WO 8701599 A1 [0010]
• DE 19626924 C2 [0011]
• EP 0925085 A1 [0012]
• WO 9801176 A1 [0012, 0036]
• DE 3413037 C2 [0013]
• DE 3422066 C2 [0013]
• DE 3412118 A1 [0026]
• WO 2006079484 A1 [0027]
• EP 1393773 A1 [0027]
• EP 0962234 A1 [0027]
• EP 0645162 B [0027]

Claims (14)

Dosing device for adding at least one pharmaceutically active substance to a breathing gas provided extracorporeally, characterized in that the dosing device has at least one dosing valve and at least one gas flow control device, as well as a control for controlling the at least one dosing valve and the at least one gas flow control device, the gas flow control device having at least one inlet connection for connection to a breathing gas source, has a patient-side outlet and a vent outlet, the control having at least one connection for at least one sensor device. Dosing device after Claim 1 , characterized in that the at least one sensor device comprises an electrical sensor for recording neuronal signals. Dosing device according to one of the preceding claims, characterized in that the at least one sensor device comprises an electrical sensor for detecting an expansion of a patient's chest. Dosing device according to one of the preceding claims, characterized in that the gas flow control device comprises a directional valve, preferably a 3/2-way valve. Dosing device according to one of the preceding claims, characterized in that a device for emitting a signal for electrical or electromagnetic stimulation of the phrenic nerve is also provided. Method for operating a metering device for adding at least one pharmaceutically active substance to a breathing gas provided extracorporeally with the following steps: - detecting at least one measurement signal from at least one sensor device, - converting the at least one measurement signal into at least one parameter value, - Activating a first metering valve at a predetermined time after detecting a predetermined size for a parameter value, so that the metering of a specific amount of the at least one pharmaceutically active substance takes place, and - Controlling a gas flow control device for the breathing gas at a predetermined time depending on the control of the first metering valve, so that an amount of gas containing the pharmaceutically active substance corresponding to the amount of gas metered into the breathing gas through the first metering valve is vented into the environment. Procedure according to Claim 6 , characterized in that the metering of a specific amount of the at least one pharmaceutically active substance to the breathing gas takes place at a predetermined time after detecting a predetermined value for the at least one parameter. Procedure according to Claim 6 , characterized in that the metering of a certain amount of pharmaceutically active substance takes place at a certain time in relation to the beginning of an inhalation phase or an electrical or electromagnetic stimulation. Procedure according to one of the Claims 6 until 8th , characterized in that a first metering valve is activated to meter out a certain amount of pharmaceutically active substance for a predetermined period of time. Procedure according to one of the Claims 6 until 9 , characterized in that the metering of a certain amount of pharmaceutically active substance takes place in one or more pulses. Procedure according to Claim 10 , characterized in that a predetermined amount of pharmaceutically active substance is added with each pulse. Procedure according to one of the Claims 6 until 11 , characterized in that the control of a first metering valve for metering a certain amount of pharmaceutically active substance and the control of a gas flow control device for the breathing gas is regulated depending on the concentration of the pharmaceutically active substance and / or depending on the volume flow downstream of the metering valve . Dosing device or method according to one of the preceding claims, characterized in that the at least one pharmaceutically active substance contains oxygen and/or surfactant and/or a drug. Ventilator with a dosing device according to one of the Claims 1 until 5 and 13 , to carry out a procedure according to one of the Claims 6 until 12 .

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