WO2007035093A2

WO2007035093A2 - Administering and evacuation system

Info

Publication number: WO2007035093A2
Application number: PCT/NL2006/000478
Authority: WO
Inventors: Gerardus Wilhelmus Lugtigheid
Original assignee: Think! Global B.V.
Priority date: 2005-09-26
Filing date: 2006-09-26
Publication date: 2007-03-29
Also published as: WO2007035093A3; NL1030026C1

Abstract

An apparatus for administering a gas other than ambient air to a patient via the airways, comprising a face mask (202) provided with fitting means (202A) which can be fitted over the nose and mouth on the patient’s face, thereby forming a breathing space (203) closed off in a substantially leakproof manner, an air supply (204) for supplying ambient air which opens into the breathing space (203) via a check valve (204A) which closes upon exhalation, which air supply (204) is provided with manually operable blocking means (204C), an evacuation line (206) which opens into the breathing space (203) via a check valve (206A) which closes upon exhalation, for evacuating, from the breathing space (203), gas present therein, and a supply of gas (205) with gas other than ambient air which opens into the breathing space (203), which supply is provided with a demand valve (205).

Description

Administering and evacuation system

The invention relates to a method and apparatus for combined administering and evacuation of a gas other than ambient air, and more in particular to an apparatus which can be connected with a face mask which is provided and fitted on a patient in order to administer a gas other than ambient air and to evacuate the exhaled gas.

Examples of gases other than ambient air which can be administered to patients and which are preferably to be evacuated during exhalation are nitric oxide and nitrous oxide. Nitrous oxide is a narcotic gas, which is often used in hospitals and ambulances. Nitrous oxide is usually administered together with oxygen as one mixture (laughing gas) via the face mask of an administering and evacuation system specially intended for this purpose. The face mask and consequently the administering and evacuation system can be put on and taken off by the patient himself as desired. The administration is then regulated by a demand valve, which opens when the patient places the face mask connected thereto over his mouth and nose and inhales. The demand valve is also provided with a check valve and a coupling piece for connection to an evacuation system in order to evacuate all gases exhaled therein, including the largely exhaled nitrous oxide.

The administration of nitrous oxide causes a light sedation which makes the patient calm during the medical treatment. As long as the patient is conscious, he will be able to place the face piece over his own mouth and nose to administer a mixture of nitrous oxide and oxygen (laughing gas) to himself without intervention of the staff in attendance, while the exhaled gases are evacuated. With a deeper sedation, the patient will no longer be capable of this and the demand valve will automatically stop the supply of laughing gas so that overdosing is prevented. At the same time, nitrous oxide present in the patient's lungs and exhaled nitrous oxide is no longer evacuated, so that the staff present is exposed to this.

There are environments where the limit value for nitrous oxide is 50 pprα in an eight-hour working day. In spaces where nitrous oxide is administered, considerably higher concentrations can be found.

The effects of prolonged exposure to laughing gas described in the literature include: neurological disorders and reduced fertility.

Combined administering and evacuation systems for, for instance, laughing gas are known from practice. Sabre Safety supplies, for instance, a demand valve, which is provided with a gas supply line, a check valve and a patient connection which is connected to a face mask. A coupling piece intended for connection to an evacuation system is also provided.

The advantage of such a system is that the patient himself can regulate the administration of a mixture of, for instance, nitrous oxide and oxygen by placing the face piece over his mouth and nose and then exhaling. The disadvantage thereof is that the gases exhaled by the patient are exclusively evacuated in case the face mask is placed over his mouth and nose and not as soon as the patient lowers the face mask. Should the patient continuously place the face mask over his mouth and nose in order to avoid this effect, then this can lead to overdosing.

Separate evacuation systems are also known from practice. WO2004010892 describes an evacuation system for narcotic gas, which comprises a (ring-shaped) housing with one or more openings which can be provided near the mouth (for instance around the neck) of the patient, while the housing is connected with evacuation means for evacuating the exhaled narcotic gases.

The advantage of such a system is that the exhaled gases are permanently evacuated. The disadvantage thereof is that the patient cannot influence the administration himself and that not all exhaled narcotic gases are evacuated.

The invention contemplates an effective method and apparatus for combined administration and evacuation of a gas other than ambient air whereby above-mentioned disadvantages can be obviated while maintaining the advantages.

To this end, the invention provides an apparatus according to claim 1. The apparatus may, for instance, be provided with an ambient air supply, in particular an ambient air supply line or ambient air supply channel (a bypass) for admitting ambient air with a closing means therein which is forced into an opened position by a coil spring, which closing means can be closed off by means of a push button. By simultaneously closing off the ambient air and inhaling, it can be achieved that the supply of, for instance, laughing gas or a mixture of nitric oxide and oxygen is activated and the patient can inhale such a mixture. Preferably, the apparatus is provided with check valves which prevent exhaled gases from flowing through the air supply channel to the environment and prevent gases from the evacuation line from being inhaled. In this manner, in practice, an effective separation between inhalation and exhalation is obtained and the patient can choose to inhale either ambient air via the air supply channel or a gas other than ambient air, for instance laughing gas or a mixture of oxygen and nitric oxide, via the demand valve. An additional advantage of the use of this air supply channel is that the face mask can permanently be fitted over the patient's mouth and nose. It is thus achieved that the risk of leakage and consequently exposure of the staff present is minimized. The check valve in the evacuation opening takes over the function of the check valve in the above-mentioned demand valve, which therefore needs to be removed. Such an apparatus may be designed in various manners, so that it can simply be provided in an existing system for administering gas other than ambient air. Preferably, the air supply channel is dimensioned such that, in opened position of the closing means, the ambient air can flow in freely and without limitations.

The invention also relates to a method for combined administration and evacuation of gas other than ambient air.

The invention will now be explained in more detail with reference to exemplary embodiments shown in the drawing, in which: Fig. 1 shows a schematic representation of an apparatus according to the invention for combined administration and evacuation of gas other than ambient air in a condition of rest;

Fig. 2 shows a schematic representation of the apparatus of Fig. 1 with opened air supply; Fig. 3 shows a schematic representation of the apparatus of Fig. 2 with opened gas discharge;

Fig. 4 shows a schematic representation of the apparatus of Fig. 3 with opened gas supply;

Fig. 5 shows a schematic cross section of an apparatus known from practice for combined administration and evacuation of gas other than ambient air;

Fig. 6 shows a schematic cross section of the apparatus of Fig. 5 designed with a first embodiment of a supply and evacuation system according to the invention; Fig. 7 shows a schematic cross section of an air supply element according to the invention of Fig. 6 with opened air supply;

Fig. 8 shows a schematic cross section of an air supply element according to the invention of Fig. 6 with closed air supply; Fig. 9 shows a schematic cross section of a second embodiment of the apparatus of Fig. 6 of a supply and evacuation system according to the invention;

Fig. 10 shows a schematic cross section of a third embodiment of the apparatus of Fig. 6 of a supply and evacuation system according to the invention;

Fig. 11 shows a schematic cross section of a fourth embodiment of the apparatus of Fig. 6 of a supply and evacuation system according to the invention; Fig. 12 shows a schematic cross section of a fifth embodiment of the apparatus of Fig. 6 of a supply and evacuation system according to the invention;

Fig. 13 shows a schematic cross section of a sixth embodiment of the apparatus of Fig. 6 of a supply and evacuation system according to the invention;

Fig. 14 shows a perspective view of the apparatus of Fig. 6; and

Fig. 15 shows a perspective view of the apparatus of Fig. 10.

The drawings are only schematic, non-limiting representations of preferred embodiments of the invention. In the Figures, same and corresponding parts are designated by corresponding reference numerals.

Fig. 1 shows a schematic representation of an administering and evacuation system 1 according to the invention in a condition of rest. The administering and evacuation system 1 is an apparatus which provides administering a gas other than ambient air to a patient via the airways. To this end, the administering and evacuation system 1 comprises a face mask 2 provided with fitting means 2A which can be fitted over the nose and mouth on a patient's face, thereby forming a breathing space 3 closed off in a substantially leakproof manner. Via an air valve device 4, ambient air can be supplied to the breathing space 3. To this end, for supply of ambient air, the air valve device 4 is provided with an ambient air opening 4B towards the ambient air and a check valve 4A. The valve device 4 is further provided with manually operable blocking means 4C, so that the patient himself can influence whether he wishes to inhale ambient air or gas other than ambient air. The blocking 4C is preferably set such that the ambient air opening 4B is opened in a condition of rest. The administering and evacuation system 1 further comprises a gas valve device 5 for the demand-driven supply of gas other than ambient air, for instance a mixture of nitric oxide and oxygen or laughing gas (a mixture of nitrous oxide and oxygen), to the breathing space 3. The gas valve device 5 for the supply of gas other than ambient air comprises a gas demand valve 5A with a predetermined threshold value. The gas demand valve 5A will only open when the threshold value is exceeded. Gas other than ambient air is then supplied via a gas connecting opening 5B, to which a supply line for such a gas can be connected. Evacuation of gases from the breathing space 3 takes place via an evacuation valve device 6, comprising an evacuation check valve 6A and an evacuation opening 6B to which an evacuation system can be connected.

Fig. 2 shows the administering and evacuation system 1 with an opened air supply element 4 during inhalation. The face mask 2 is on a patient's face. When the patient inhales, the check valve 4A will open — as shown in Fig. 2. The air supply is opened now and ambient air flows to the breathing space 3 via the ambient air openings 4B and the check valve 4A. Due to the inhalation, the evacuation check valve 6A is closed, so that the patient inhales the sucked-in ambient air via the breathing space 3. The gas demand valve 5A does not open until the pressure in breathing space 3 has reached a predetermined threshold value and since the pressure will not drop below such a threshold value when the blocking means 4C are in the opened position, the gas demand valve 5A remains closed.

When the patient then exhales, the exhaled air flows into the breathing space 3 and - as shown in Fig. 3 - the check valve 4A closes, and the evacuation check valve 6A opens. Due to the overpressure which is now created in the breathing space 3, the check valve 4A closes and the gas demand valve 5A remains closed. The exhaled air can be discharged via the evacuation opening 6B of the evacuation valve device 6 to an evacuation system (not shown). In a breathing pause between inhaling and exhaling, the check valve 4 closes and remains closed due to the overpressure in the breathing space 3 realized during de exhalation. During the breathing pause, the pressure in the breathing space 3 slowly drops. Due to the slightly sucking action of the evacuation system (not shown), the evacuation check valve opens slightly during the breathing pause after inhalation.

If the patient operates the blocking means 4C, as shown in Fig. 4, then he thereby closes off the ambient air openings 4B. Now when the patient inhales, an underpressure is created in the breathing space 3 which exceeds the threshold value of the gas demand valve 5A, so that the gas demand valve 5A opens. Due to the underpressure created, the evacuation check valve 6A is closed. Via the gas connecting opening 5B of the gas valve device 5, gas other than ambient air can now be supplied to the breathing space 3 so that the patient can inhale the gas.

In addition, it is the case that the gas supply line connected to opening 5B supplies gas under a certain overpressure in the direction of the gas demand valve 5A. If, in breathing space 3, the pressure reaches a predetermined threshold value (underpressure value), this gas demand valve 5A opens. This is because, by inhaling, the pressure difference between breathing space 3 and the demand valve 5A increases — the pressure in the breathing space 3 itself drops below a predetermined underpressure value — so that the gas demand valve opens. By stopping inhaling, the pressure difference between breathing space 3 and the demand valve 5A decreases again, so that the gas demand valve closes. The level of pressure difference required to open the gas demand valve is higher than the level of pressure difference to close this valve. Now if the patient exhaled with pressed blocking means 4C, the evacuation check valve 6A would open in the same manner as in Fig. 3 so that the exhaled gas can be discharged via the evacuation opening 6B. When the patient stops inhaling, the pressure difference with breathing space 3 exceeds the threshold value, so that the gas demand valve 5A closes.

In an advantageous manner, the check valve 4A closing off the air supply which opens into the breathing space upon exhalation forms a second demand valve for supplying ambient air. In the administering and evacuation system 1, the gas demand valve 5A forms a first demand valve. The second demand valve 4A opens at a predetermined underpressure value in the breathing space 3, while this predetermined underpressure value is chosen so as to be smaller in an absolute sense than the predetermined underpressure value at which the first gas demand valve 5A opens.

Fig. 5 shows a schematic cross section of an apparatus 101 known from practice for combined administration and evacuation of gas other than ambient air. In this example, the administering and evacuation system 101 is provided with a face mask 102 for placement over the mouth and nose on a patient's face which is placed on the patient connection 102C. The administering and evacuation system 101 known from practice is usually supplied without face mask 102, for instance the system 101 is supplied by Sabre Safety. The nursing staff, for instance in a hospital, connects a face mask 102 from another supplier to the patient connection 102A. Typically, this face mask 102 cannot be locked and there are no fitting means for fitting the face mask 102 on the face, because then overdosing would occur due to inhaling gas other than ambient air without a break. The valve device 105 of Sabre Safety comprises a demand valve 105A and a gas connecting opening 105B for connection to a supply line for gas other than ambient air. The operation of the demand valve device 105 is based on a pressure-sensitive membrane which operates a needle valve as a lever, which needle valve regulates the gas supply. GB 2274595 contains a description of the operation of such a system. For discharge of gases from the breathing space 103, evacuation check valves 106A are provided. In this embodiment of the Sabre Safety system, a separately supplied coupling piece 107 is provided which is placed on the valve device 105 for connection to an evacuation system.

Fig. 6 shows an administering and evacuation system 201 where the air valve device 204 is included in an air supply element. The air supply element (bypass element) according to the invention is connected to the adjusted administering and evacuation system 101 of Fig. 5. Here, the check valve 106A is replaced by check valve 206A, so that breathing space 203 is in open communication with coupling piece 207 via the outflow openings 205C. In addition, the face mask 202 is coupled to the demand valve device 205 via a lock 202B. This lock 202B may be a detachable coupling with the housing of the demand valve device 205. The threshold value of the demand valve 205A at which it opens for the supply of gas other than ambient air is preset at a lower pressure value than the threshold value at which the check valve 204A opens upon inhalation.

Fig. 7 shows the air supply element (bypass element) according to the invention, comprising a housing 208 with a channel 215 extending between a first opening 216 for connection to a face mask and a second opening 206B for connection to an evacuation system. The connection to a face mask can take place directly or indirectly to the first opening 216, and in this exemplary embodiment as used in Fig. 6, the connection takes place indirectly. The air supply element further comprises an air supply channel 214 surrounded by a valve housing 204, which air supply channel 214 extends from at least one suction opening 204B to the channel 215, while manually operable blocking means 204C are included in the air supply channel 214. The valve housing 209 comprises a closing means housing 209 with ring-shaped edge 209A, a button 210 connected with a closing means 210A, which is pressed against edge 209A by coil spring 211. In this exemplary embodiment, the manually operable blocking means 204C thus comprise a push button 210 under spring action with a closing means 210A. Optionally, the blocking means 204C comprise a push button under spring action with a valve body blocking the air supply channel 214 when operated. Closing means housing 209 further comprises a ring-shaped closing means seating 209B, gates 204B, ring-shaped channel 213 and check valve 204A being supported by valve seating 213A. The channel 213 communicates with channels 214 and 215 as soon as the check valve 204A opens. In an advantageous embodiment, the air supply channel 214 and optionally the channel 215 in the housing 208 are each provided with a check valve, as shown here in Fig. 7. A check valve 204A is provided for air supply channel 214 and an evacuation check valve 206A is provided for channel 215. The housing 208 further comprises the channel 215 which communicates with channel 214 and a check valve 206A with valve seating 206C and openings 206B and 216. In this exemplary embodiment as used in Fig. 6, check valve 206A replaces the check valve 106A of Fig. 5. Opening 206B can be connected to an evacuation system (not shown) and, in the embodiment as shown in Fig. 6, opening 216 is connected to the coupling piece 207 shown there intended for connection of an evacuation system. The gas connection for, for instance, nitrous oxide is preferably designed with a restriction which maximizes the flow at 16 L/min. The evacuation system preferably has a capacity of at least 35 L/min, so that no leakage of, for instance, laughing gas is possible. For that same reason, the face mask is preferably fitted to the patient's face with bands. In order to be able to fit the face mask to the patient's face in a leakproof manner, the face mask may, for instance, be provided with a conventional inflatable rim or soft collar. When the patient inhales, check valve 206A closes on valve seating 206C and check valve 204A opens, so that ambient air flows through gates 204B via channels 213, 214 and 215 to the face mask and is inhaled by the patient. When the patient exhales, check valve 204A close on valve seating 213A and check valve 206A opens, so that the exhaled air is evacuated via opening 206B.

Fig. 8 shows the situation that the button 210 is pressed, so that the closing means 210A, supported by seating 209B, closes off the gates 204B and no ambient air can flow in. Now when the patient inhales, an underpressure is created in channel 214 and channel 215 so that check valve 206A closes and the gas supply is activated by the demand valve system (not shown). The gas other than ambient air flows to the face mask and is inhaled by the patient. When the patient no longer inhales, the demand valve system closes off the supply of the gas other than ambient air. As soon as the patient exhales, check valve 206A opens, so that the exhaled air with, for instance, nitrous oxide therein is evacuated. Further, the air supply channel is rinsed with ambient air, so that no harmful gases can escape. Above-mentioned parts may, for instance, be manufactured from synthetic material. When metal is chosen, for instance for the spring, then, for instance, phosphor bronze may be used to prevent magnetic influences. This allows use of the air supply element in and on the MRI.

The invention is also suitable to administer an aerosol as the gas other than ambient air to a patient and to evacuate the exhaled aerosol. Here, a demand-driven aerosol generator such as a vaporizer may be provided.

Fig. 9 shows a second embodiment of the administering and evacuation system 301 according to the invention. The valve device 305 of Sabre Safety known from practice is used for the supply of gas other than ambient air and the coupling piece 307 (also supplied by Sabre Safety) for the discharge of gases to the evacuation system is also used here. However, the threshold value of the demand valve 305A in the valve device 305 is adjusted so that, upon inhalation, while the blocking means 304C are in the opened position, the check valve 304A standardly opens. Due to the increased threshold value, the demand valve 305A only opens when the ambient air openings 304B are closed off by pressing the closing means 304C.

In the embodiment of Fig. 9, the air valve device 304 is placed between the face mask 302 ands the demand valve device 305 in a coupling piece 308. Since the demand valve device 305 developed by Sabre Safety already has a check valve 306A and an opening 306B for connection to the evacuation system, in this embodiment, in contrast with the embodiment as designed and shown in Fig. 6, an independent evacuation valve device for the discharge of gases from breathing space 303 is omitted.

Fig. 10 shows a third embodiment of the apparatus of Fig. 6 of an administering and evacuation system 401 according to the invention. In this embodiment, the air valve device 404 is placed on the face mask 402. The face mask 402 is optionally locked to the patient connection 402C with locking means 402B. Due to the locking, the system 401 becomes safer to use. Further, here, the face mask 402 is provided with fitting means 402A to fit the face mask 402 on the patient's face. After use, the face mask 402 with the air valve device 404 fitted thereon is sterilized for reuse or thrown away, depending on its design. Optionally, a reusable air valve device 404 can be coupled with the back part of a disposable face mask 402 via a detachable coupling. Also, a disposable air valve device 404 can be fitted to the disposable face mask 402 before use, while they both can be thrown away after use.

Fig. 11 shows a schematic cross section of a fourth embodiment of the apparatus of Fig. 6 of an administering and evacuation system 501 according to the invention. In the demand valve device 505 known from practice, the evacuation check valve is removed, and now it is located in the evacuation valve device 506 of the air supply system according to the. invention. At the location of 505D, the existing openings are closed. This adjusted demand valve device 505 is directly connected to the face mask 502 via the patient connection 502C. The back part of the face mask 502 which is provided with an opening 502D for connection to the patient connection 502C, is, in this example, provided with two extra connecting openings; in one opening, the air valve device 504 for the supply of ambient air is supported and in one opening, the evacuation valve device 506 for the discharge of gases from breathing space 503 is supported. The two devices are placed separately from each other at two different locations on a back part of the face mask 502 operatively facing away from the user's face. Optionally, the air valve device 504 and/or the evacuation valve device 506 may be detachably coupled to the back part of the face mask 502. Further, the face mask 502 may be detachably coupled with the demand valve device 505.

A fifth embodiment of an administering and evaluation system 601 according to the invention is shown in Fig. 12. This is a variant of the embodiment which is shown in Fig. 11. The air valve device 604 for the supply of ambient air and the evacuation valve device 606 for the discharge of gases are directly intercoupled by coupling piece 608 and placed on the face mask 602 with one connection.

A sixth embodiment is shown in Fig. 13 and is also more or less in line with Fig. 11. Now air valve device 704 for the supply of ambient air is taken off the mask again and placed between the demand valve device 705 and the face mask 702 via a coupling piece 708. In this example, the evacuation valve device 706 for discharging gases is still on the mask. Optionally, the air valve device 704 may also be integrated in the demand valve device 705, so that a coupling piece 708 would become redundant. Also, the face mask 702 can be coupled to the housing of the demand valve device 705 via a detachable coupling.

Fig. 14 shows a perspective view of the apparatus of Fig. 6. It can clearly be seen how the face mask 202 can be fitted on the patient's face via the fitting means 202A. The blocking means 204C of the air valve device 204 are located between the demand valve device 205 and the evacuation valve device 206, where they are well operable for the patient. Fig. 15 shows a perspective view of the apparatus of Fig. 10, where the air valve device 404 is supported on a back part of the face mask 402 operatively facing away from the patient's face. Here, the blocking means 404 are also well accessible to and can simply be operated by the patient himself, so that he himself can influence when he wishes to inhale ambient air or gas other than ambient air.

The apparatus, the face mask and the air supply element are preferably built up from separate parts which are preferably detachable.

With such a construction, certain parts can be reused and exchanged, and other parts can be designed as disposable parts. In particular, it is advantageous to design the face mask, whether or not provided with the air supply element, as a disposable unit. The invention is not limited to the above-described exemplary embodiments. Many variations are possible within the range of the invention as set forth in the following claims.

Claims

1. An apparatus for administering a gas other than ambient air to a patient via the airways, comprising a face mask provided with fitting means which can be fitted over the nose and mouth on a patient's face, thereby forming a breathing space closed off in a substantially leakproof manner, an air supply for supplying ambient air which opens into the breathing space via a check valve which closes upon exhalation, which air supply is provided with manually operable blocking means, an evacuation line which opens into the breathing space via a check valve which closes upon exhalation, for evacuating, from the breathing space, gas present therein, and a supply of gas with gas other than ambient air which opens into the breathing space, which supply is provided with a demand valve which opens at a predetermined underpressure in the breathing space which is caused by inhalation with blocked air supply line.

2. An apparatus according to claim 1, wherein the air supply which opens into the breathing space via a check valve which closes upon exhalation forms a second demand valve for supplying ambient air to the breathing space, and wherein the predetermined underpressure value at which this second demand valve opens is chosen so as to be smaller in an absolute sense than the predetermined underpressure value at which the first demand valve opens for supplying the gas other than ambient air.

3. An apparatus according to claim 1 or 2, wherein the blocking means are arranged so as to be open in unoperated condition.

4. An apparatus according to claim 3, wherein the blocking means comprise a push button under spring action with closing means.

5. An apparatus according to any one of the preceding claims, wherein the air supply which opens into the breathing space via a check valve which closes upon exhalation is supported on a coupling piece between the face mask and a housing for the first demand valve.

6. An apparatus according to any one of the preceding claims, wherein the air supply which opens into the breathing space via a check valve which closes upon exhalation is supported on a back part of the face mask operatively facing away from the user's face.

7. An apparatus according to any one of the preceding claims, wherein the check valve for the evacuation line is supported on a back part of the face mask operatively facing away from the user's face.

8. An apparatus according to claim 6 or 7, wherein the air supply which opens into the breathing space via a check valve which closes upon exhalation and/or the check valve for the evacuation line are detachably coupled with the back part of the face mask with the aid of a detachable coupling.

9. An apparatus according to any one of the preceding claims, wherein the face mask is detachably coupled with the housing for the first demand valve or the coupling piece with the aid of a detachable coupling.

10. An apparatus according to any one of the preceding claims, wherein the air supply which opens into the breathing space via a check valve which closes upon exhalation is included in an air supply element, an air supply channel surrounded by a valve housing for connection to a face mask or to a coupling piece connected with a face mask, wherein the supply channel extends from at least one suction opening, and wherein manually operable blocking means are included in the air supply channel.

11. An apparatus according to any one of the preceding claims, wherein the second demand valve for supplying ambient air to the breathing space is integrated with the first demand valve for supply of gas other than ambient air and wherein the predetermined underpressure value of the second demand valve is chosen so as to be smaller in an absolute sense than the predetermined underpressure value at which the first demand valve for supplying gas other than ambient air opens.

12. A face mask for an apparatus according to any one of the preceding claims, comprising a back part provided with fitting means, which back part can operatively be fitted over the nose and mouth on the patient's face with the fitting means, thereby forming a breathing space closed off in a substantially leakproof manner, which back part is at least provided with two separate connecting openings.

13. A face mask according to claim 12, wherein, in one of the connecting openings, a demand valve is supported for supplying ambient air to the breathing space.

14. A face mask according to claim 12 or 13, wherein, in one of the connecting openings, an evacuation line provided with a check valve is supported for evacuating, from the breathing space, gas present therein.

15. A face mask according to any one of claims 12-14, wherein one of the connecting openings is provided with a detachable coupling for detachably coupling with a demand valve for supplying ambient air to the breathing space and/or an evacuation line provided with a check valve for evacuating, from the breathing space, gas present therein.

16. A face mask according to any one of claims 12-15, wherein at least one connecting opening is provided with a detachable coupling for detachably coupling with the housing for a first demand valve or coupling piece.

17. An air supply element for an apparatus for administering a gas other than ambient air to a patient via the airways, comprising a housing with a channel extending between a first opening for direct or indirect connection to a face mask and a second opening for connection to an evacuation system, further comprising an air supply channel surrounded by a valve housing, which extends from at least one suction opening to the channel, wherein manually operable blocking means are included in the air supply channel.

18. An air supply element according to claim 17, wherein the manually operable blocking means comprise a push button under spring action with a valve body which blocks the air supply channel when operated.

19. An air supply element according to claim 17 or 18, wherein the air supply channel and optionally the channel in the housing are each provided with a check valve.

20. A method for administering a gas other than ambient air to a patient via the airways, wherein a face mask is fitted over the nose and mouth on the patient's face, thereby forming a breathing space closed off in a substantially leakproof manner, and wherein the patient can inhale ambient air from the breathing space supplied via an air supply line, and wherein the gases exhaled by the patient in the breathing space and any other gases present therein are evacuated when the patient does not inhale, wherein the patient can temporarily activate a supply of gas other than ambient air to the breathing space by temporary, manual blocking of the air supply line during inhalation.

21. A method according to claim 20, wherein the gas other than ambient air comprises a medicinal concentration of nitric oxide.

22. A method according to claim 20, wherein the gas other than ambient air comprises a medicinal concentration of nitrous oxide.

23. A method according to claim 20, 21 or 22, wherein the air supply line automatically opens upon inhalation when the manual blocking is unoperated.