SUPPLY ARRANGEMENT AND PROCESS FOR SAFELY SUPPLYING A MEDICAL DEVICE WITH A GAS MIXTURE

Abstract

A supply arrangement (100) and a process supply a medical device (50, 90) with a supply gas mixture. The supply gas mixture includes a carrier gas and an anesthetic and is generated by an anesthetic dispenser (3). A carrier gas mixing unit (9) generates the carrier gas from at least two carrier gas components. A carrier gas switch having a regular outlet and a discharge outlet selectively directs carrier gas components to the carrier gas mixing unit or to a discharge line (35). A gas mixture switch (6), having a regular outlet (41) and a discharge outlet (42) selectively directs the supply gas mixture to the medical device or to the discharge line (35). An anesthetic concentration sensor (5.1, 5.2) measures a concentration of anesthetic in the generated gas mixture. A control unit (2) controls the gas mixture switch based on measured concentration within or outside a predefined range.

Claims

1. A supply arrangement for supplying a medical device with a supply gas mixture comprising a carrier gas, comprised of two or more carrier gas components, and anesthetic, the supply arrangement comprising: an anesthetic dispenser configured to generate the supply gas mixture using the anesthetic and the carrier gas; a gas mixture switch with a gas mixture switch inlet, a gas mixture switch regular outlet and a gas mixture switch discharge outlet, and operable in a regular position, in which a fluid connection is established between the gas mixture switch inlet and the gas mixture switch regular outlet, and in a discharge position, in which a fluid connection is established between the gas mixture switch inlet and the gas mixture switch discharge outlet, wherein the gas mixture switch is configured to direct the supply gas mixture to the gas mixture switch regular outlet or to the gas mixture switch discharge outlet depending on the position of the gas mixture switch; a carrier gas mixing unit configured to generate the carrier gas using the carrier gas components; a carrier gas supply line which connects the carrier gas mixing unit to the anesthetic dispenser; a gas mixture supply line which connects the anesthetic dispenser to the inlet of the gas mixture switch; a gas mixture supply line which connects the regular outlet of the gas mixture switch to the medical device; a discharge line arrangement connecting the discharge outlet of the gas mixture switch to a gas sink that is physically separate from the medical device, or leads into an environment, the discharge line arrangement comprising at least one discharge line; and a carrier gas switch arrangement comprising at least one carrier gas switch, wherein the carrier gas switch or each carrier gas switch of the carrier gas switch arrangement comprises a carrier gas switch inlet; a carrier gas switch regular outlet and a carrier gas switch discharge outlet and is operable in a regular position, in which a fluid connection is established between the carrier gas switch inlet and the carrier gas switch regular outlet, and in a discharge position, in which a fluid connection is established between the carrier gas switch inlet and the carrier gas switch discharge outlet and with the carrier gas switch regular outlet connected to a component of the carrier gas mixing unit or to the anesthetic dispenser and the carrier gas switch discharge outlet connected to the discharge line arrangement, wherein the carrier gas switch is arranged such that one or more carrier gas components flow through the carrier gas switch inlet to the carrier gas switch regular outlet or to the carrier gas switch discharge outlet depending on the position of the carrier gas switch.

2. A supply arrangement according to claim 1, further comprising: a signal processing control unit; and a state sensor arrangement comprising at least one state sensor which is configured to measure an indicator for a state of a component of the supply arrangement or to measure an indicator for a state of a gas or gas mixture flowing into, through, or out of the supply arrangement, wherein the control unit is configured to control the gas mixture switch depending on a signal from the state sensor such that the gas mixture switch directs the supply gas mixture to the regular outlet with the signal indicating a measured state within a predetermined permissible range and directs the supply gas mixture to the discharge outlet with the signal indicating a measured state outside the predetermined permissible range.

3. A supply arrangement according to claim 2, wherein: a required concentration range of components in the supply gas mixture is predetermined, which range determines a desired concentration of components of the supply gas mixture; the state sensor arrangement comprises a component concentration sensor configured to measure an indicator for an actual concentration of the component in the supply gas mixture; and the control unit is configured to control the gas mixture switch depending on a signal from the component concentration sensor such that the gas mixture switch directs the supply gas mixture to the regular outlet with a measured concentration of the component in the supply gas mixture within the required concentration and the gas mixture switch directs the supply gas mixture to the discharge outlet with the measured concentration outside the required concentration range.

4. A supply arrangement according to claim 1, further comprising: a signal processing control unit; and a carrier gas component concentration sensor configured to measure an indicator for an actual concentration of at least one carrier gas component in a gas mixture generated by the carrier gas mixing unit, wherein a required concentration range for the carrier gas component is specified which defines a required concentration of the carrier gas component in the carrier gas or in the supply gas mixture, and wherein the control unit is configured to control the gas mixture switch or control the carrier gas switch arrangement, or control both the gas mixture switch and the carrier gas switch arrangement depending on a signal from the carrier gas component concentration sensor such that the controlled switch directs a gas or gas mixture flowing through the inlet of the switch to the regular outlet with a concentration of the carrier gas component measured by the carrier gas concentration sensor that is within the required concentration range, and directs a gas or gas mixture flowing through the inlet of the switch to the discharge outlet with the measured carrier gas component concentration that is outside the required concentration range.

5. A supply arrangement according to claim 1, wherein: the carrier gas is composed of a first carrier gas component, a second carrier gas component and a third carrier gas component; and the carrier gas mixing unit comprises: a first mixer configured to generate an intermediate gas mixture using the first and second carrier gas components; and a second mixer configured to generate the carrier gas using the intermediate gas mixture and the third carrier gas component.

6. A supply arrangement according to claim 5, wherein: The carrier gas switch or at least one carrier gas switch is arranged such that the inlet of the carrier gas switch is connected to an outlet of the first mixer and the regular outlet of the carrier gas switch is connected to an inlet of the second mixer; and the carrier gas switch directs the intermediate gas mixture generated by the first mixer to the second mixer in the regular position and to the discharge line arrangement in the discharge position.

7. A supply arrangement according to claim 6, further comprising: a signal processing control unit; and a carrier gas component concentration sensor for the first carrier gas component or a carrier gas component concentration sensor for the second carrier gas component or both a carrier gas component concentration sensor for the first carrier gas component and a carrier gas component concentration sensor for the second carrier gas component, wherein a required concentration range is specified for the first carrier gas component or for the second carrier gas component or for both the first carrier gas component and for the second carrier gas component, wherein the carrier gas component concentration sensor is configured to measure an indicator for the concentration of the first carrier gas component in the intermediate gas mixture or in the carrier gas or the concentration of the second carrier gas component in the intermediate gas mixture or in the carrier gas or both the concentration of the first carrier gas component in the intermediate gas mixture or in the carrier gas and the concentration of the second carrier gas component in the intermediate gas mixture or in the carrier gas, and wherein the control unit is configured to control depending on a signal from the carrier gas component concentration sensor the carrier gas switch which is connected to the outlet of the first mixer.

8. A supply arrangement according to claim 5, further comprising: a mixer bypass line that bypasses the second mixer and is connected to the carrier gas supply line; and a mixer bypass switch comprising a bypass switch inlet connected to an outlet of the first mixer, a bypass switch regular outlet connected to an inlet of the second mixer, and a bypass switch outlet connected to the mixer bypass line, wherein the mixer bypass switch directs the intermediate gas mixture to the regular outlet in a regular position and directs the intermediate gas mixture to the bypass outlet in a bypass position.

9. A supply arrangement according to claim 8, further comprising: a signal processing control unit; and a carrier gas component concentration sensor configured to measure an indicator for an actual concentration of the third carrier gas component in the carrier gas or in the supply gas mixture, wherein a required concentration range is specified for the concentration of the third carrier gas component in the carrier gas or in the supply gas mixture, and wherein the control unit is configured to control the mixer bypass switch depending on a signal from the carrier gas component concentration sensor such that the mixer bypass switch directs the intermediate gas mixture to the regular outlet with the a measured actual concentration of the third carrier gas component in the supply gas mixture within the required concentration range, and directs the intermediate gas mixture to the bypass outlet, with the measured actual concentration of the third carrier gas component in the supply gas mixture outside the required concentration range.

10. A supply arrangement according to claim 1, further comprising: a carrier gas bypass line connected to the gas mixture supply line and bypassing the anesthetic dispenser; and a carrier gas bypass switch comprising a carrier gas bypass switch inlet connected to an outlet of the carrier gas mixing unit, a carrier gas bypass switch regular outlet connected to the carrier gas supply line or to the inlet of the gas mixture switch and a carrier gas bypass switch bypass connected to the carrier gas bypass line, wherein the carrier gas bypass switch directs the carrier gas to the regular outlet in a regular position and directs the carrier gas to the bypass outlet in a bypass position.

11. A supply arrangement according to claim 10, further comprising: an anesthetic concentration sensor configured to measure an indicator for an actual concentration of the anesthetic in the supply gas mixture; and a signal processing control unit, wherein a required concentration range for the concentration of the anesthetic in the supply gas mixture is specified for the anesthetic, and wherein the controller is configured to control the carrier gas bypass switch such that the carrier gas bypass switch directs the carrier gas to the regular outlet with the actual concentration of the anesthetic within the required concentration range, and directs the carrier gas to the bypass outlet with the actual concentration of the anesthetic outside the required concentration range.

12. A supply arrangement according to claim 1, further comprising a carrier gas component supply line, wherein the carrier gas switch arrangement has an inlet connected to the carrier gas component supply line.

13. A supply arrangement according to claim 12, a signal processing control unit; and a carrier gas component volume flow sensor configured to measure an indicator for an actual volume flow of the carrier gas component through the associated carrier gas component supply line, wherein a target volume flow range is specified for the carrier gas component associated with carrier gas component volume flow sensor, and wherein the control unit is configured to control the carrier gas switch arrangement to direct the carrier gas component to the regular outlet if the measured actual volume flow is within the specified target volume flow range, and direct the carrier gas component to the discharge outlet if the measured actual volume flow is outside the specified target volume flow range.

14. An anesthetic system comprising: a patient-side coupling unit connectable to a patient; and a supply arrangement configured to provide a supply gas mixture comprising a carrier gas, comprised of two or more carrier gas components and anesthetic, the supply arrangement comprising: an anesthetic dispenser configured to generate the supply gas mixture using the anesthetic and the carrier gas; a gas mixture switch with a gas mixture switch inlet, a gas mixture switch regular outlet and a gas mixture switch discharge outlet, and operable in a regular position, in which a fluid connection is established between the gas mixture switch inlet and the gas mixture switch regular outlet, and in a discharge position, in which a fluid connection is established between the gas mixture switch inlet and the gas mixture switch discharge outlet, wherein the gas mixture switch is configured to direct the supply gas mixture to the gas mixture switch regular outlet or to the gas mixture switch discharge outlet depending on the position of the gas mixture switch; a carrier gas mixing unit configured to generate the carrier gas using the carrier gas components; a carrier gas supply line which connects the carrier gas mixing unit to the anesthetic dispenser; a gas mixture supply line which connects the anesthetic dispenser to the inlet of the gas mixture switch; a gas mixture supply line which connects the regular outlet of the gas mixture switch to a medical device; and a discharge line arrangement which connects the discharge outlet of the gas mixture switch to a gas sink that is physically separate, or leads into an environment, the discharge line arrangement comprising at least one discharge line; and a carrier gas switch arrangement comprising at least one carrier gas switch, wherein the carrier gas switch or each carrier gas switch of the carrier gas switch arrangement comprises an carrier gas switch inlet; a regular gas switch regular outlet and a carrier gas switch discharge outlet and is operable in a regular position, in which a fluid connection is established between the carrier gas switch inlet and the carrier gas switch regular outlet, and in a discharge position, in which a fluid connection is established between the carrier gas switch inlet and the carrier gas switch discharge outlet and with the carrier gas switch regular outlet connected to a component of the carrier gas mixing unit or to the anesthetic dispenser and the carrier gas switch discharge outlet connected to the discharge line arrangement, wherein one or more carrier gas components flow through the carrier gas switch inlet to the carrier gas switch regular outlet or to the carrier gas switch discharge outlet depending on the position of the carrier gas switch, wherein the gas mixture supply line connects the regular outlet of the gas mixture switch to the patient-side coupling unit.

15. Anesthetic system according to claim 14, further comprising a ventilator, wherein the gas mixture supply line leads from the regular outlet of the gas mixture switch to the ventilator, and wherein the ventilator is configured to deliver the supply gas mixture to the patient-side coupling unit.

16. A process of supplying a medical device with a supply gas mixture comprising a carrier gas and at least one anesthetic, wherein the process is performed with a supply arrangement comprising: an anesthetic dispenser; a gas mixture switch comprising a gas mixture switch inlet, a gas mixture switch regular outlet, and a gas mixture switch discharge outlet; a carrier gas mixing unit; a carrier gas supply line connecting the carrier gas mixing unit to the anesthetic dispenser; a gas mixture supply line connecting the anesthetic dispenser to the gas mixture switch inlet; a gas mixture supply line connecting the gas mixture switch regular outlet to the medical device; a discharge line arrangement connecting the discharge outlet of the gas mixture switch to a gas sink that is physically separate from the medical device, or leads into an environment, the discharge line arrangement comprising at least one discharge line; and a carrier gas switch arrangement comprising at least one carrier gas switch, wherein the carrier gas switch or each carrier gas switch of the carrier gas switch arrangement comprises a carrier gas switch inlet; a carrier gas switch regular outlet and a carrier gas switch discharge outlet and is operable in a regular position in which a fluid connection is established between the carrier gas switch inlet and the carrier gas switch regular outlet, and in a discharge position in which a fluid connection is established between the carrier gas switch inlet and the carrier gas switch discharge outlet and with the carrier gas switch regular outlet connected to a component of the carrier gas mixing unit or to the anesthetic dispenser and the carrier gas switch discharge outlet connected to the discharge line arrangement, the process comprising the steps of: generating the carrier gas with the carrier gas mixing unit using at least two different carrier gas components; generating the supply gas mixture with the anesthetic dispenser using the anesthetic and the carrier gas; and with the carrier gas switch arrangement, directing a gas or a gas mixture flowing through the carrier gas switch inlet to the regular carrier gas switch outlet or to the discharge carrier gas switch outlet depending on the position of the carrier gas switch.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0103] In the drawings:

[0104] FIG. 1 is a schematic view showing the integration of a supply arrangement according to the invention into a system which artificially ventilates and anesthetizes a patient;

[0105] FIG. 2 is a schematic view showing the structure of the supply arrangement of FIG. 1 according to the invention;

[0106] FIG. 3 is a schematic view showing a serial configuration of the carrier gas mixing unit with a feed into the discharge line;

[0107] FIG. 4 is a schematic view showing a cascaded configuration of the carrier gas mixing unit with several feeds into the discharge line;

[0108] FIG. 5 is a schematic view showing a serial configuration of the carrier gas mixing unit with a feed into the bypass line;

[0109] FIG. 6 is a schematic view showing a cascaded configuration of the carrier gas mixing unit with several feeds into the bypass line.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0110] In the embodiment example, the invention is used in an anesthesia system 1, with the aid of which a patient P is artificially ventilated and anesthetized. FIG. 1 schematically shows the patient, the system 1 and its supply of fluids.

[0111] The patient P is connected to a schematically shown patient-side coupling unit 50 during artificial respiration, for example with a breathing mask on the face or a tube or catheter in the body. The anesthesia system 1 is connected to the patient-side coupling unit 50 by a line arrangement 37 comprising a plurality of parallel lines (lumens). Thus, a closed ventilation circuit is established between the patient P and the anesthesia system 1.

[0112] The anesthesia system 1 includes a ventilator 90 that performs a sequence of ventilation strokes. During each ventilation stroke, a quantity of a supply gas mixture flows from the ventilator 90 through a lumen of the line arrangement 37 to the patient-side coupling unit 50 and further to the patient P. The supply gas mixture comprises a carrier gas with oxygen and anesthetic. An optional anesthetic concentration sensor 5.3 measures the concentration of the anesthetic in the supply gas mixture flowing through the line arrangement 37 to the patient-side coupling unit 50. Exhaled air flows through another lumen of the line arrangement 37 from the patient P back to the anesthesia system 1. The anesthesia system 1 maintains the closed ventilation circuit between the ventilator 90 and the patient P. The anesthesia system 1 is configured to provide a closed ventilation circuit between the patient P and the ventilator 90. Preferably, the ventilator 90 removes carbon dioxide from the exhaled air. It is possible that patient P is fully anesthetized and is ventilated solely by the artificial ventilation. It is also possible that the artificial ventilation supports the patient P's own respiratory activity.

[0113] In an alternative embodiment not shown, the ventilator 90 is omitted. Also in this alternative embodiment, the patient P is supplied with a supply gas mixture comprising a carrier gas with oxygen and anesthetic, and also in this alternative embodiment, the patient P is at least temporarily connected to the patient-side coupling unit 50. The patient P takes in the supply gas mixture by means of the patient P's own respiratory activity, i.e., by means of his own respiratory muscles. For example, patient P performs sufficiently strong spontaneous breathing. Or patient P's own respiratory musculature is stimulated externally, for example by electrical pulses or in a magnetic field. It is possible that the externally stimulated respiratory activity supports the patient P's spontaneous breathing.

[0114] The following description refers to the embodiment according to FIG. 1 and can be transferred to the alternative embodiment. The carrier gas in the embodiment example consists of three components, namely the three gases breathing air, oxygen and nitrous oxide (N2O). It is also possible that the carrier gas comprises fewer and/or more or other components. In any embodiment, the carrier gas comprises oxygen as one component, for example pure oxygen or breathing air with oxygen. It is also possible that the anesthetic is added directly to a stream of breathing air. In this case, this stream of breathing air acts as the carrier gas to which the anesthetic is added. The stream of breathing air can circulate in the closed ventilation circuit. Preferably, the ventilator 90 maintains this ventilatory circuit.

[0115] The supply arrangement 100 of the embodiment according to the invention is part of the anesthesia system 1 and supplies the ventilator 90 or directly the coupling unit 50 on the patient side with this gas mixture. A gas mixture supply line 33 leads from the supply arrangement 100 to the ventilator 90 or directly to the patient-side coupling unit 50.

[0116] A stationary supply port 21 in a wall W provides the three gaseous components breathing air, oxygen and nitrous oxide (N2O) for the carrier gas. These three components are supplied to the supply arrangement 100 via the three lines 28. It is possible for the supply port 21 to provide at least one additional or different component, or even fewer than three components. Also in this case, the carrier gas is generated from the provided carrier gas components and comprises oxygen. It is also possible that the supply arrangement 100 is supplied with the carrier gas components from mobile storage containers, for example metal bottles.

[0117] A supply port 20 in wall W provides compressed air or oxygen or other pressurized gas. The pressurized gas is directed to the supply arrangement 100 through a conduit 29. The use of this positive pressure is described further below.

[0118] A discharge configuration comprising at least one discharge line 35 leads from the supply arrangement 100 to a gas receptacle (gas sink) 22 in the wall W. The discharge line 35 is capable of leading a gas mixture from the supply arrangement 100 to the gas receptacle 22. This gas mixture may contain anesthetic and in particular may be the supply gas mixture.

[0119] The exhaust line 35 and the gas receptacle 22 prevent a gas mixture containing an anesthetic from entering the environment of the anesthesia system 1, where it could harm people's health. Preferably, the gas receptacle 22 further prevents this gas mixture from entering a room and/or another device in the hospital via the inpatient infrastructure system of a hospital.

[0120] In one embodiment, the gas receptacle 22 is connected to a suction system, such as a pump, wherein said suction system draws a gas mixture through the discharge line 35 to the gas receptacle 22. In another embodiment, the gas mixture is delivered to the gas receptacle 22 by an overpressure. In a third embodiment, a hose downstream of the gas receptacle 22 directs the gas mixture to a filter arrangement that filters out narcotics from the gas mixture. In a further embodiment, a gas line downstream of the gas receptacle 22 directs the gas mixture to another processing system or disposal system. It is also possible that the gas receptacle 22 discharges the gas mixture into the open air.

[0121] In the embodiment described below, the carrier gas is generated from three components: oxygen (O2), breathing air, and nitrous oxide (N2O), and gaseous anesthetic is fed into this carrier gas. The ventilator 90 is supplied with a supply gas mixture of the carrier gas and the anesthetic, and the supply gas mixture is fed into the ventilation circuit. It is also possible that the carrier gas is fed into the ventilation circuit at a first feed point and the anesthetic is fed into the ventilation circuit at a spatially spaced second feed point. It is also possible that at times no separate carrier gas is used and only the gaseous anesthetic is fed into the ventilation circuit.

[0122] FIG. 2 schematically shows the structure of the supply arrangement 100 according to the invention. The following components of the supply arrangement 100 are shown: [0123] an anesthetic dispenser 3, which generates the supply gas mixture from the carrier gas and the anesthetic and comprises a mixing chamber 11, in which the anesthetic is added to the carrier gas, [0124] a volume flow sensor 5.4 that measures an indicator for the volume flow of anesthetic into the mixing chamber 11, for example the saturated vapor flow of anesthetic, [0125] a heater 10 for the mixing chamber 11 of the anesthetic dispenser 3, [0126] an anesthetic tank 4 for liquid anesthetic, [0127] the line 29 through which the pressurized gas flows from the supply port 20 to the anesthetic tank 4, [0128] a front anesthetic concentration sensor 5.1 and a rear anesthetic concentration sensor 5.2, each measuring an indicator for the concentration of the anesthetic in the supply gas mixture generated by the anesthetic dispenser 3, wherein the designations “front” and “rear” refer to the direction of flow of the supply gas mixture to the ventilator 90, [0129] a carrier gas mixing unit 9, which generates the carrier gas from the three gases breathing air, oxygen and nitrous oxide and comprises a plurality of mixers 9.1, 9.2, . . . , [0130] the three lines 28 through which the three carrier gas components breathing air, oxygen and nitrous oxide flow from the supply connections 21 to the carrier gas mixing unit 9, [0131] a pneumatic gas mixture switch 6 comprising a switch valve, the gas mixture switch 6 comprising an inlet 40, a regular outlet 41, and a discharge outlet 42, [0132] the discharge line 35 leading from the discharge outlet 42 of the gas mixture switch 6 to the gas receiver 22, [0133] optionally a front buffer storage (front buffer reservoir) 7.1 and a rear buffer storage (rear buffer reservoir) 7.2 between the anesthetic dispenser 3 and the respirator 90, wherein each buffer storage 7.1, 7.2 can temporarily store the supply gas mixture, i.e. can receive a certain quantity of the gas mixture and later release it again, [0134] the gas mixture supply line 33 leading from the regular outlet 41 of the gas mixture switch 6 to the ventilator 90, and [0135] a signal processing control unit 2.

[0136] The three anesthetic concentration sensors 5.1, 5.2 and 5.3 and the volume flow sensor 5.4 are arranged at different measuring points and measure at least one variable at the respective measuring point which correlates with the anesthetic concentration in the gas mixture, for example directly the concentration, a volume flow, a cycle rate of an injection system for an anesthetic or also several of these variables. Optionally, a pressure sensor not shown measures the pressure over time in the mixing chamber 11.

[0137] The volume flow of anesthetic can be approximately derived from the measured pressure in the mixing chamber 11, the flow of carrier gas into the mixing chamber 11, and the known volume of the mixing chamber 11. This embodiment creates redundancy because the volume flow of anesthetic is calculated in two different ways.

[0138] The three anesthetic concentration sensors 5.1, 5.2 and 5.3 optionally apply at least two different measuring principles. The control unit 2 is able to determine the concentration of the anesthetic at the respective measuring point from the measured values of the three anesthetic concentration sensors 5.1, 5.2 and 5.3 and the volume flow sensor 5.4. This concentration can vary not only over time, but also from measuring point to measuring point.

[0139] In the figures, these three as well as optionally further concentration sensors are arranged at different measuring points. Preferably, the anesthesia system 1 comprises a central concentration measuring unit, which is connected to each of the different measuring points via a fluid guide unit, as well as a selection arrangement, which ensures that the concentration measuring unit is pneumatically connected to exactly one measuring point at any time, optionally to no measuring point at all during a pause in operation. The gas mixture is guided from the respective measuring point through the fluid guide unit to the concentration measuring unit and preferably through another lumen of the same fluid guide unit back to the measuring point. This embodiment makes it possible to measure the respective concentration at different measuring points and still require only one central concentration measuring unit. The selection arrangement comprises, for example, one controllable switching valve per measuring point and thus per fluid guide unit.

[0140] The gaseous anesthetic is added to the carrier gas in the mixing chamber 11. The anesthetic dispenser 3 can add anesthetic to the carrier gas, in particular by vaporization or evaporation or by injection. For example, an injection valve not shown injects liquid anesthetic into the mixing chamber 11, and there the liquid anesthetic is heated and thereby becomes gaseous. Or the liquid anesthetic is vaporized in the mixing chamber 11, for example with the aid of the heater 10, and thereby becomes gaseous.

[0141] The optional front buffer 7.1 is located between the mixing tank 11 and the gas mixture switch 6, and the optional rear buffer 7.2 is located between the regular outlet 41 of the gas mixture switch 6 and the ventilator 90. In the embodiment, the front buffer 7.1 and the gas mixture switch 6 are located outside the ventilator 90. The rear buffer 7.2 may be located inside or outside the ventilator 90. In the embodiment shown in FIG. 2, the rear buffer storage 7.2 is located outside the ventilator 90 and is in fluid communication with the gas mixture supply line 33.

[0142] In one embodiment, the capacity of the connecting line 31 is such that the connecting line 31 itself acts as a buffer storage and a separate front buffer storage 7.1 is not used. Accordingly, in one embodiment, the capacity of the gas mixture supply line 33 is such that the gas mixture supply line 33 itself acts as a buffer storage and a separate rear buffer storage 7.2 is not used. In this embodiment, the volume of the line 31 or 33 is preferably variable.

[0143] A rear carrier gas supply line 27 guides the carrier gas from the carrier gas mixing unit 9 to the mixing tank 11. A line 30 guides liquid anesthetic from the anesthetic tank 4 to the anesthetic dispenser 3. A connecting line 31 guides the generated gas mixture from the mixing tank 11 of the anesthetic dispenser 3 to the front buffer storage 7. A connecting line 32 leads from the front buffer storage 7.1 to the inlet 40 of the gas mixture switch 6. The gas mixture supply line 33 leads from the regular outlet 41 of the gas mixture switch 6 to the ventilator 90.

[0144] A bypass line 34 for oxygen, breathing air and/or nitrous oxide leads from the carrier gas mixing unit 9 to the gas mixture supply line 33. This bypass line 34 bypasses the anesthetic dispenser 3, the two buffer storages 7.1 and 7.2 and the gas mixture switch 6 and opens into the gas mixture supply line 33 downstream of the regular outlet 41 of the gas mixture switch 6. A bypass switch 56 with an inlet, a regular outlet and a bypass outlet is part of the mixing unit 9 and is capable of selectively directing oxygen, breathing air and/or nitrous oxide from the carrier gas mixing unit 9 into the carrier gas supply line 27 or into the bypass line 34. A front carrier gas supply line 47 leads from the mixers 9.1, 9.2, . . . to the inlet of the bypass switch 56. An optional controllable proportional valve 8 in the bypass line 34 can block the bypass line 34 or change the flow rate of gas through the bypass line 34.

[0145] The front anesthetic concentration sensor 5.1 measures an indicator for the concentration of the anesthetic in the supply gas mixture flowing through the connection line 31 to the front buffer storage 7.1. The rear concentration sensor 5.2 measures the concentration of anesthetic in the supply gas mixture flowing through the gas mixture supply line 33 to the ventilator 90.

[0146] The supply arrangement 100 is operable in a supply mode. In the supply mode, the supply arrangement provides the supply gas mixture of the carrier gas with oxygen and anesthetic. Before the supply arrangement 100 is operated in the supply mode during anesthetization of the patient P, it is operated in an initialization mode. In particular, operation in the initialization mode has the following objectives: [0147] Anesthetic which may be present from a previous use in the anesthetic dispenser 3 or in a line of the supply arrangement 100 is removed. Such anesthetic still present from a previous use could lead to incorrect dosing of the anesthetic in the current use. [0148] The functionality of the supply arrangement 100 without the anesthetic dispenser 3 and the functioning of the supply connections 21 are checked. [0149] Lines of the supply arrangement 100 are checked for leaks.

[0150] In addition, the initialization mode allows a first medical treatment to be performed using an anesthetic and a subsequent second medical treatment to be performed using the same supply arrangement 100 not using an anesthetic. Therefore, anesthetic must be removed from the supply arrangement 100 prior to commencing the second treatment.

[0151] The carrier gas mixing unit 9 also generates the carrier gas in the initialization mode. However, the anesthetic dispenser 3 is deactivated and therefore does not feed any anesthetic into the carrier gas. The carrier gas flows through the supply arrangement 100 to the gas mixture switch 6. Any anesthetic present is carried along by the carrier gas and thus removed from the anesthetic dispenser 3. While the supply arrangement 100 is operating in the initialization mode, the gas mixture switch 6 directs the carrier gas from the inlet 40 to the discharge outlet 42. The carrier gas enters the discharge line 35 and does not reach the ventilator 90 or the patient-side coupling unit 50.

[0152] Optionally, the respective pressure in different lines of the supply arrangement 100 is measured. If the pressure measured in a downstream measuring point is significantly lower than a pressure measured in an upstream measuring point, an indication of leakage is found. If the pressure at each measuring point is too low, a supply port 21 may not be supplying enough gas.

[0153] A user or also a higher-level signal-processing control unit specifies a setpoint concentration of the anesthetic in the supply gas mixture, whereby the ventilator 90 and thus the patient P are to be supplied with this supply gas mixture. This setpoint concentration can be variable over time. The control unit 2 receives measured values from the anesthetic concentration sensors 5.1, 5.2 and 5.3 and from the volume flow sensor 5.4. The anesthetic concentration sensors 5.1, 5.2 and 5.3 directly measure, for example, the concentration or the volume flow or the clock rate of an injection system of the anesthetic dispenser 3. It is possible that the anesthetic concentration sensors 5.1, 5.2 and 5.3 and the volume flow sensor 5.4 apply at least two different measuring principles in total. Depending on measured values, the control unit 2 determines the temporal course of the actual concentration of the anesthetic in the supply gas mixture, which flows through the connection line 31 or the gas mixture supply line 33 or the line arrangement 37, at the respective measuring point.

[0154] Preferably, the control unit 2 performs a closed-loop control or an open-loop control with the aim of ensuring that the specified time profile of the setpoint concentration matches the time profile of the measured actual concentration of the anesthetic in the supply gas mixture. The control unit 2 controls two valves, not shown, in the carrier gas supply lines 47 or 27 and 30, and optionally an injection valve in the mixing chamber 11, in order to change the actual concentration of the anesthetic in the gas mixture generated in the mixing chamber 11 in the event of a control deviation. For this control, the control unit 2 uses the measured values from the front anesthetic concentration sensor 5.1, which is located upstream of the front buffer storage 7.1. In many cases, the control interventions effected by the control unit 2 lead to a rapid reduction of the control deviation. The generated gas mixture flows through the front buffer storage 7.1. In many cases, this results in the actual concentration of the anesthetic in the gas mixture supply line 33 differing less from the target concentration than the actual concentration in the connection line 31. In addition, the front buffer storage 7.1 reduces the time fluctuations of the control deviation.

[0155] The concentration of the anesthetic in the supply gas mixture flowing through the gas mixture supply line 33 to the ventilator 90 must be within a predetermined target range. The concentration must not be less than the lower bound of this target range in order for the patient P to remain reliably anesthetized. The concentration must also not be above the upper limit, because too high a concentration can be toxic or even lethal for patient P.

[0156] The control unit 2 automatically decides whether the concentration of the anesthetic in the supply gas mixture flowing through lines 31, 32 and 33 is within the target range or not. For this decision, the control unit 2 uses measured values from at least one of the two anesthetic concentration sensors 5.1 and 5.2 and/or from the volume flow sensor 5.4. As long as the measured actual concentration of the anesthetic is in the target range, the inlet 40 of the gas mixture switch 6 is connected to the regular outlet 41. The gas mixture flows from the connection line 32 into the gas mixture supply line 33 and through the gas mixture supply line 33 on to the ventilator 90. Part of this gas mixture is temporarily stored in the rear buffer storage 7.2.

[0157] If, on the other hand, the actual concentration in the mixing chamber 11, the connection line 31 and/or in the gas mixture supply line 33 is outside the setpoint range, the control unit 2 activates the gas mixture switch 6 so that the inlet 40 is now connected to the discharge outlet 42. The gas mixture from the connection line 32 therefore flows through the discharge line 35 to the gas receptacle 22 and no longer into the gas mixture supply line 33. The gas mixture with the faulty concentration is therefore kept away from the ventilator 90 and thus from the patient P. The gas receptacle 22 receives the gas flowing through the line 35 and prevents anesthetic from leaking into the environment of the anesthesia system 1, which is undesirable.

[0158] In one embodiment of the invention, the control unit 2 controls the gas mixture switch 6 depending on measured values of the rear anesthetic concentration sensor 5.2. In one possible implementation, the control unit 2 additionally uses measured values of the front anesthetic concentration sensor 5.1 and/or the volume flow sensor 5.4. If the measured values of the front anesthetic concentration sensor 5.1 and/or the volume flow sensor 5.4 indicate that the concentration of the anesthetic in the gas mixture supply line 33 will be outside the target range despite control unit 2 interventions, the control unit 2 activates the gas mixture switch 6 and causes the gas mixture to be directed from the connection line 32 to the discharge outlet 42 and to flow through the discharge line 35 to the gas receiver 22.

[0159] The control unit 2 is also capable of controlling the bypass switch 56 downstream of the mixer—9.1, 9.2, . . . of the carrier gas mixing unit 9. This bypass switch 56 is described in more detail below.

[0160] When the gas mixture switch 6 directs the gas mixture into the discharge line 35, the ventilator 90 no longer receives any gas mixture from the anesthetic dispenser 3. The ventilator 90 is still supplied with the required gas mixture from the rear buffer storage 7.2 for a certain time. Thanks to the rear buffer storage 7.2, it is not necessary in many cases to disconnect the patient P from the anesthesia system 1 even if the gas mixture switch 6 directs the gas mixture into the discharge line 35. Such disconnection would in many cases interrupt the anesthetization of patient P and should therefore be avoided.

[0161] In an embodiment, the volume of the rear buffer storage 7.2 is variable, preferably in that at least one wall of the rear buffer storage 7.2 is elastic. In one embodiment, a hand-held respiratory bag is used as the rear buffer storage 7.2. The front buffer storage 7.1 can have a rigid housing.

[0162] In one embodiment, the respective storage capacity of the two buffer storages 7.1 and 7.2 can be configured depending on the following parameters of the supply arrangement 100: [0163] from the volume flow of the gas mixture from the anesthetic dispenser 3 to the ventilator 90 and [0164] of the time required for the control unit 2 to detect a concentration outside the target range depending on measured values of at least one anesthetic concentration sensor 5.1, 5.2 and for the gas mixture switch 6 to be switched over in order to divert the gas mixture into the discharge line 35.

[0165] Preferably, the control unit 2 generates an alarm when the gas mixture is directed from the line 32 to the discharge line 35 and from there to the gas receiver 22 and not to the gas mixture supply line 33 and from there to the ventilator 90. In this case, the control unit 2 and/or a user decide which of the following actions will be performed: [0166] The incorrect actual concentration of the anesthetic has been caused by an incorrect presetting of the target concentration or by only a brief malfunction of the anesthetic dispenser 3 or a supply connection 21. The actual concentration comes back into the target range in which it must be, for example by a corrected presetting or by an automatic self-correction of the anesthetic dispenser 3 or the supply connection 21. As soon as the actual concentration is back in the target range, the control unit 2 preferably automatically switches the gas mixture switch 6 back to the previous state so that the gas mixture reaches the regular outlet 41 and on to the ventilator 90. [0167] The anesthetic dispenser 3 must be switched off and restarted and then tested, in particular automatically calibrated. [0168] The carrier gas mixing unit 9 must be switched off and restarted and then tested, in particular automatically calibrated.

[0169] The period of time during which the ventilator 90 is supplied with the gas mixture from the rear buffer storage 7.2 is usually sufficient for the anesthetic dispenser 3 to correct itself. In many cases, the time span is also sufficient for the anesthetic dispenser 3 and/or the carrier gas mixing unit 9 to be switched off, restarted and tested.

[0170] If this time period is not sufficient, the control unit 2 causes the proportional valve 8 to be opened and the bypass switch 56 to be switched. Pure oxygen or even breathing air flows from the supply port 21 through the bypass line 34 into the gas mixture supply line 33 and from there to the ventilator 90. Such a function with a bypass line 34 is described, for example, in DE 20 2011 102 318 U1 (corresponding U.S. Pat. No. 9,283,347 is hereby incorporated by reference). Possible embodiments are described below with reference to FIG. 3 and FIG. 4.

[0171] In the embodiment just described, the gas mixture is directed from line 32 to discharge line 35 and from there to gas receiver 22 when the control unit 2 has detected a concentration of the anesthetic outside the target range. In one embodiment, the anesthetic dispenser 3 must perform a self-test from time to time, optionally with subsequent calibration, and even if no malfunction has been detected. The control unit 2 repeatedly switches the anesthetic dispenser 3 to a self-test mode after a predetermined period of use has elapsed and, in doing so, controls the gas mixture switch 6 so that the gas mixture switch 6 directs the gas mixture from the line 32 to the discharge line 35. Therefore, the self-test does not affect the concentration of an anesthetic in the gas mixture. The ventilator 90 is supplied with the required gas mixture from the rear buffer storage 7.2.

[0172] FIG. 3 and FIG. 4 show two possible embodiments of how a usable carrier gas can be produced despite a possible malfunction of a mixer 9.1, 9.2, . . . of the carrier gas mixing unit 9 or of a supply connection 21. In the example shown, the carrier gas is to be composed of the three gases oxygen, breathing air and nitrous oxide, whereby the three required proportions of the three gases in the carrier gas and a required volume flow of the carrier gas are specified. These specifications result in a required volume flow for each of the three gases breathing air, oxygen and nitrous oxide to the carrier gas mixing unit 9. One principle of the two embodiments shown is that, as far as possible, the carrier gas or the gas mixture of the carrier gas and the anesthetic is used, even if a carrier gas component is not supplied correctly.

[0173] FIG. 3 shows an embodiment in which the gas mixture is generated by supplying the three carrier gas components oxygen, breathing air and nitrous oxide (N2O) and then the anesthetic in series. Supply ports 21.1, 21.2, 21.3 feed oxygen and breathing air and nitrous oxide, respectively, into supply lines 28.1 and 28.2 and 28.3, respectively. A mixer 9.1 feeds the breathing air from supply line 28.2 into the stream of oxygen flowing through supply line 28.1. A mixture of oxygen and breathing air flows through line 28.4. A mixer 9.2 feeds nitrous oxide from supply line 28.3 into this mixture of oxygen and breathing air, producing the carrier gas. The carrier gas flows through the two carrier gas supply lines 47 and 27 to the mixing chamber 11. In the mixing chamber 11, the anesthetic is added to this carrier gas.

[0174] Three volume flow sensors 25.1, 25.2, and 25.3 each measure an indicator for the volume flow of oxygen, breathing air, and nitrous oxide, respectively, in the supply line 28.1, 28.2, and 28.3, respectively. A volume flow or concentration sensor 25.4 measures at a measurement point in the line 28.4 a measure of [0175] the volume flow of the mixture of oxygen and air and/or [0176] the concentration of breathing air and/or [0177] the concentration of oxygen in this mixture.

[0178] A volume flow or concentration sensor 25.5 measures, at a measurement point in the rear carrier gas supply line 27, a measure of [0179] the volume flow of the carrier gas and/or [0180] the concentration of breathing air in the carrier gas and/or [0181] the concentration of oxygen in the carrier gas and/or [0182] the concentration of nitrous oxide in the carrier gas.

[0183] In one embodiment, sensors 25.4, 25.5 are also connected to the central concentration measurement unit described above.

[0184] The aforementioned anesthetic concentration sensor 5.1 measures the concentration of anesthetic in the gas mixture flowing through the connection line 31.

[0185] It is possible that the volume flow of one of the three carrier gas components oxygen, breathing air and nitrous oxide for the carrier gas is outside a specified volume flow range. A special case is that a carrier gas component is not injected at all due to a fault. It is also possible that the concentration of one of these three components in the carrier gas is outside a specified concentration range. In either case, the carrier gas that reaches the mixing chamber 11 is composed of the other two components. Even then, the carrier gas still comprises oxygen. This is shown in FIG. 3 as an example for the carrier gas component nitrous oxide, which is provided by the supply port 21.3.

[0186] The volume flow sensor 25.3 measures the volume flow of nitrous oxide through the supply line 28.3. The volume flow or concentration sensor 25.5 measures the volume flow of carrier gas through the rear carrier gas supply line 27 and/or the concentration of nitrous oxide in the carrier gas. If the volume flow and concentration of oxygen, breathing air and nitrous oxide through the supply lines 28.1, 28.2 and 28.3 respectively are correct, the mixer 9.2 feeds the nitrous oxide into the already generated mixture of oxygen and air.

[0187] If the control unit 2 detects that the volume flow or concentration of nitrous oxide through the rear carrier gas supply line 27 is too large or too small, or that no nitrous oxide is being supplied at all, the following two steps are triggered: [0188] A carrier gas switch 6.3 directs the gas mixture with the incorrect volume flow or concentration of nitrous oxide from the rear carrier gas supply line 27 into a line 35.1. This line 35.1 opens into the discharge line 35, which in turn leads to the gas receiver 22. [0189] A mixer bypass switch 6.10 directs the mixture of oxygen and breathing air, which flows through line 28.4 and which has the correct volume flow, into a mixer bypass line 39. This mixer bypass line 39 opens downstream of mixer 9.2 and upstream of the carrier gas switch 6.3 into the rear carrier gas supply line 27, thus bypassing the mixer 9.2 and also the sensor 25.5. A mixture of oxygen and air then flows through the rear carrier gas supply line 27 into the mixing chamber 11.

[0190] This embodiment allows a usable carrier gas to be provided despite an incorrect volume flow or concentration of nitrous oxide, namely from the other two components of breathing air and oxygen. It is not necessary to interrupt the operation of the supply arrangement 100.

[0191] In one possible embodiment, the reaction to the detection that the volume flow or concentration of nitrous oxide is too high is as follows: The carrier gas switch 6.3 is repeatedly switched, and thereby the carrier gas switch 6.3 alternately diverts the gas mixture into the supply line 31 or into the discharge line 35. This embodiment reduces the concentration of nitrous oxide in the carrier gas, but ensures that the carrier gas contains nitrous oxide. According to this embodiment, the reaction to a too low volume flow or concentration is as follows: Carrier gas component switches 6.4 and 6.5 for oxygen and breathing air are repeatedly switched over so that the concentration of nitrous oxide is increased.

[0192] If the volume flow or concentration sensor 25.4 measures an incorrect volume flow or concentration of oxygen or breathing air in the line 28.4, the control unit 2 controls a carrier gas switch 6.9. The actuated carrier gas switch 6.9 directs the gas or gas mixture flowing through line 28.4 into a line 35.9. This line 35.9 leads into the discharge line 35. It is also possible that the control unit 2 actuates the gas mixture switch 6 in such a way that the actuated gas mixture switch 6 directs the supply gas mixture to the discharge outlet 42. Both configurations rule out with a high degree of certainty that the patient P receives a supply gas mixture with too low a proportion of oxygen.

[0193] FIG. 3 also shows a carrier gas component switch 6.5 in the supply line 28.2 for breathing air and a carrier gas component switch 6.6 in the supply line 28.3 for nitrous oxide. If the volume flow sensor 25.2 measures an incorrect or missing volume flow of breathing air through the supply line 28.2, the carrier gas component switch 6.5 diverts the flow of breathing air from the line 28.2 into a line 35.5. If the volume flow sensor 25.3 measures an incorrect or missing volume flow of nitrous oxide through the supply line 28.3, the carrier gas component switch 6.6 diverts the flow of nitrous oxide from the line 28.3 into a line 35.6. The lines 35.5 and 35.6 open into the discharge line 35.

[0194] It is possible to provide at least one bypass line for the mixer 9.1 in the same way as just described for nitrous oxide. Thanks to this bypass line for the mixer 9.1, it is possible for the carrier gas to contain breathing air but no oxygen or, conversely, oxygen but no breathing air. It is ensured that the carrier gas contains breathing air or oxygen or both. In general, it is possible to provide such a bypass line for each mixer of the supply arrangement 100.

[0195] FIG. 4 shows an example of a different configuration in which the three gases oxygen, breathing air and nitrous oxide as well as the anesthetic are supplied in cascade. Identical reference signs have the same meanings as in FIG. 3. A mixer 9.3 mixes the two components oxygen and air of the carrier gas to form an intermediate gas mixture which flows through the line 28.5. An intermediate gas mixture of nitrous oxide and gaseous anesthetic is generated in the mixing chamber 11. This intermediate gas mixture flows through line 28.6. Mixer 9.3 is arranged parallel to mixing chamber 11. Mixer 9.4 generates the desired gas mixture consisting of the carrier gas with oxygen, breathing air and nitrous oxide and the anesthetic from the two gas mixtures in the two lines 28.5 and 28.6.

[0196] In the embodiment shown in FIG. 4, six volume flow sensors are provided, namely the three volume flow sensors 25.1, 25.2, 25.3 as in the embodiment according to FIG. 3, as well as a further volume flow sensor 25.7, which measures the volume flow of liquid anesthetic in line 30. The two volume flow or concentration sensors 25.6, 25.8 measure the concentration of a component or the volume flow in the lines 28.5 and 28.6, respectively, and can also be connected to the central concentration measuring unit.

[0197] A carrier gas component switch 6.1 is able to direct oxygen, which flows through the supply line 28.1, optionally to the mixer 9.3 or into the discharge line 35. A carrier gas component switch 6.2 is capable of directing breathing air, which flows through the supply line 28.2, selectively to the mixer 9.3 or into the discharge line 35. A carrier gas component switch 6.6 is capable of directing nitrous oxide, which flows through the supply line 28.3, selectively to the mixing chamber 11 or into the discharge line 35. A carrier gas switch 6.7 is capable of directing the gas mixture of oxygen and breathing air, which flows from the mixer 9.3 through the line 28.5, selectively to the mixer 9.4 or into the discharge line 35. A switch valve 6.8 is capable of directing the gas mixture of nitrous oxide and anesthetic, which flows from the mixing chamber 11 through line 28.6, either to the mixer 9.4 or into the discharge line 35.

[0198] Again, the following advantage is achieved: If one of the three components oxygen, breathing air and nitrous oxide of the carrier gas is not sufficiently provided, a carrier gas can still be provided, said carrier gas comprising breathing air and/or oxygen.

[0199] If too high a volume flow and/or too high a concentration of nitrous oxide is detected, the carrier gas component switch 6.6 is preferably repeatedly switched over and directs nitrous oxide alternately to the mixing chamber 11 or into the discharge line 35. This reduces the volume flow of nitrous oxide into the mixing chamber 11, and yet the mixing chamber 11 continues to be used. In one embodiment, if the concentration of nitrous oxide is too low, the carrier gas switch 6.7 is repeatedly switched so that the concentration of the two components oxygen and breathing gas is reduced.

[0200] With reference to FIG. 2, a bypass line 34 was described above which directs a gas from the carrier gas mixing unit 9 directly to the gas mixture supply line 33 and thus into the ventilator 90. This bypass line 34 bypasses the anesthetic dispenser 3 and the two buffer storages 7.1 and 7.2. The bypass switch 56 of the carrier gas mixing unit 9 is capable of directing a component of the carrier gas into this bypass line 34.

[0201] FIG. 5 and FIG. 6 show two configurations of this bypass switch 56 in the carrier gas mixing unit 9. The configuration according to FIG. 5 corresponds to the serial mixing according to FIG. 3, the configuration according to FIG. 6 corresponds to the cascaded mixing according to FIG. 4. The same reference signs again have the same meanings. The embodiments of FIG. 3 and FIG. 5 can be combined with each other, and the embodiments of FIG. 4 and FIG. 6 can also be combined with each other.

[0202] In the embodiment shown in FIG. 5, a pneumatic carrier gas component bypass switch 56.1 is capable of selectively directing oxygen flowing through the supply line 28.1 to the mixer 9.1 or into a line 34.1, wherein the line 34.1 leads to the bypass line 34. A pneumatic carrier gas component bypass switch 56.2 is capable of selectively directing the gas mixture flowing through line 28.4 to mixer 9.2 or into a line 34.2, with line 34.2 also leading to bypass line 34. The bypass switch 56 also shown in FIG. 2 is capable of selectively directing the gas mixture flowing through the further carrier gas supply line 47 into the carrier gas supply line 27 and thus to the mixing chamber 11, or into a line 34.3, the line 34.3 also leading to the bypass line 34.

[0203] This embodiment allows oxygen, breathing air, nitrous oxide, or a combination of several of these gases to be selectively introduced into the bypass line 34 and supplied to the patient P, bypassing the anesthetic vaporizer 3. An exemplary possibility is explained for the following case: the volume flow or concentration sensor 25.5 has detected that the volume flow of carrier gas through the further carrier gas supply line 47 or the concentration of a component in the carrier gas is incorrect. In this case, oxygen or breathing air, or a mixture of oxygen and breathing air, is directed into the bypass line 34 from the carrier gas component bypass switches 56.1 and/or 56.2. The carrier gas in the front carrier gas feed line 47 is fed into the exhaust line 35, for example from the carrier gas switch 6.3 described with reference to FIG. 3.

[0204] In the embodiment shown in FIG. 6, the carrier gas component bypass switches 56.1 and 56.4 are capable of directing oxygen or breathing air selectively to the mixer 9.3 or to the bypass line 34. The carrier gas component bypass switch 56.5 is capable of selectively conducting nitrous oxide or liquid anesthetic to the mixing chamber 11 or to the bypass line 34. The carrier gas component bypass switches 56.6 and 56.7 are capable of directing the intermediate gas mixture in lines 28.5 and 28.6, respectively, selectively to the mixer 9.4 or to the bypass line 34.

[0205] In both embodiments, the control unit 2 preferably controls the switches 56.1 to 56.8 depending on measured values of the volume flow sensors 25.1 to 25.8.

[0206] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

TABLE-US-00001 List of reference characters 1 Anesthesia system, artificially ventilates and anesthetizes patient P, includes ventilator 90, supply arrangement 100, and gas mixture supply line 33 2 signal-processing control unit, receives measured values from the concentration sensors 5.1, 5.2, 5.2, 25.1, . . . , controls the carrier gas mixing unit 9, the switches 6, 6.2 to 6.10, 56, 56.1 to 56.7 and the valve 8 3 Anesthetic dispenser, receives a carrier gas from the carrier gas mixing unit 9 and liquid anesthetic from the anesthetic tank 4, generates the supply gas mixture from the carrier gas and the vaporized anesthetic in the mixing chamber 11, comprises the heater 10 and the mixing chamber 11 4 Anesthetic tank, contains liquid anesthetic, is pressurized with gas through the supply line 29 5.1 front anesthetic concentration sensor between the anesthetic dispenser 3 and the gas mixture switch 6, measures the concentration of the anesthetic in the gas mixture flowing through the connecting line 31 5.2 rear anesthetic concentration sensor between the gas mixture switch 6 and the ventilator 90, measures the concentration of anesthetic in the gas mixture flowing through the gas mixture supply line 33 5.3 patient-side concentration sensor, measures the concentration of the anesthetic in the supply gas mixture flowing through the line arrangement 37 to the patient-side coupling unit 50 5.4 Volume flow sensor, measures the volume flow of anesthetic into the mixing chamber 11 6 pneumatic gas mixture switch in the form of a switching valve, which directs the supply gas mixture from the line 32 selectively into the discharge line 34 or into the gas mixture supply line 33, comprises the inlet 40 and the outlets 41 and 42 6.1 Carrier gas component switch, which selectively directs oxygen from the supply line 28.1 to the mixer 9.3 or to the discharge line 35 6.2 Carrier gas component switch, which directs breathing air from the supply line 28.2 selectively to the mixer 9.3 or to the discharge line 35 6.3 Carrier gas switch, which selectively directs the carrier gas in the rear carrier gas supply line 27 to the mixing chamber 11 or to the discharge line 35 6.4 Carrier gas component switch, which selectively directs oxygen from the supply port 21.1 to the mixer 9.3 or to the discharge line 35 6.5 Carrier gas component switch, which directs breathing air from supply port 21.2 selectively to mixer 9.3 or to discharge line 35 6.6 Carrier gas component switch, which selectively directs nitrous oxide from the supply port 21.3 to the mixing chamber 11 or to the discharge line 35 6.7 Carrier gas switch, which directs a mixture of oxygen and breathing air either to the mixer 9.4 or to the discharge line 35 6.8 Carrier gas switch, which directs a mixture of nitrous oxide and gaseous anesthetic selectively into mixer 9.4 or to discharge line 35 6.9 Carrier gas switch, which selectively directs a mixture of breathing air and oxygen to line 28.4 or leads the mixture into line 35.9 6.10 Mixer bypass switch, which selectively directs a mixture of oxygen and breathing air into mixer 9.2 or into mixer bypass line 39, acts as the carrier gas component bypass switch 7.1 front buffer storage between the anesthetic dispenser 3 and the ventilator 90, located upstream of the gas mixture switch 6 and between the lines 31 and 32 7.2 rear buffer storage between the anesthetic dispenser 3 and the ventilator 90, located downstream of the gas mixture switch 6 and the ventilator 90, has a variable volume, is in fluid communication with the gas mixture supply line 33 8 Proportional valve in the bypass line 34 9 Carrier gas mixing unit, generates the carrier gas from the three gases air, N2O and O2, comprises mixers 9.1 to 9.4 9.1 Mixer that feeds into a stream of O2 breathing air 9.2 Mixer that injects nitrous oxide into a gas mixture of O2 and breathing air 9.3 Mixer that feeds into a stream of O2 breathing air 9.4 Mixer which generates the carrier gas from the gas mixture of the gas mixer 9.3 and from the gas mixture from the mixing tank 11 10 Heater for the mixing tank 11 11 Mixing tank of the anesthetic dispenser 3 20 Supply connection for compressed air 21 Supply connection for the three gases breathing air, N2O and O2 21.1 Supply connection for O2 21.2 Supply connection for breathing air 21.3 Supply connection for nitrous oxide (N2O)