MXPA01012780A

MXPA01012780A - Single breath induction anesthesia apparatus.

Info

Publication number: MXPA01012780A
Application number: MXPA01012780A
Authority: MX
Inventors: Marie-Jose Colas
Original assignee: Colas Mariejose
Priority date: 1999-06-11
Filing date: 1999-11-04
Publication date: 2003-06-24
Also published as: JP2003530898A; CA2274398A1; CA2274398C; AU766922B2; AU1023100A

Abstract

A single breath induction anesthesia apparatus (10) for anesthetising a patient, comprises a gas delivery system (12) for delivering at least one gas to the patient, an oxygen supply system (14) for providing oxygen, and an oxygen/anesthesia gas supply system (16) for mixing oxygen and at least one anesthesia gas at a preset optimum ratio sufficient to cause anesthesia of the patient with a single breath, thereby providing an oxygen/anesthesia gas mixture. The apparatus (10) of the invention further includes a valve (18) for providing selective gas flow communication between the oxygen supply system (14) and the gas delivery system (12) or between the oxygen/anesthesia gas supply system (16) and the gas delivery system (12). The valve (18) is operable for first establishing gas flow communication between the oxygen supply system (14) and the gas delivery system (12) to deliver oxygen to the patient and permit pre-oxygenation thereof, while inhibiting gas flow communication between the oxygen/anesthesia gas supply system (16) and the gas delivery system (12) to allow the oxygen/anesthesia gas mixture to reach the preset optimum ratio, and thereafter establishing gas flow communication between the oxygen/anesthesia gas supply system (16) and the gas delivery system (12) to deliver the oxygen/anesthesia gas mixture to the patient and permit single breath induction anesthesia thereof, while inhibiting gas flow communication between the oxygen supply system (14) and the gas delivery system (12).

Description

SINGLE BREATH INDUCTION ANESTHESIA APPARATUS Technical Field The present invention relates to improvements in the field of anesthesia. More particularly, the invention relates to a single breath induction anesthesia apparatus. Single breath induction anesthesia is also frequently referred to in the literature as vital capacity induction anesthesia.

BACKGROUND OF THE INVENTION When it is necessary to anesthetize a patient, it is highly desirable to pre-oxygenate the patient before inducing anesthesia in order to increase the alveolar pulmonary oxygen partial pressure to increase the safety of the induction anesthesia as well as for endotracheal intubation and subsequent ventilation. The pre-oxygenation of the patient is carried out by using a breathing system and parallel oxygen supply connected by means of a conduit to a mask fixed to the patient. Due to the complexity of such a technique, pre-oxygenation is often skipped. In the case where the pre-oxygenation is carried out, while the patient who is pre-oxygenated, the doctor usually closes with his hand the distal end of the conduit connected to an anesthesia machine and adapted to supply a mixture of oxygen and / or anesthesia gas to the patient, during the operation of the anesthesia machine, to allow the anesthetic gas in the mixture to reach a preset concentration sufficient to induce anesthesia of the patient with a single breath. Since it is often impossible to close the anesthesia gas line in a gas-tight manner with one's hand, anesthesia gas leaks may occur, contaminating the operating room. Also, since the student has only one free hand, he is limited in his movements to perform other tasks. When the desired concentration of gas anesthesia has been reached, the oxygen conduit is disconnected from the mask and the anesthesia gas conduit is connected to it. Alternatively, the mask that is connected to the oxygen supply and breathing system is removed and another mask to which the anesthesia gas line has been connected is fixed to the patient. After the induction of anesthesia, the mask is then removed from the patient's face to allow the installation of a ventilation device such as an oropharyngeal ventilation duct, an endotracheal tube or a laryngeal mask. During this disconnection and connection of ducts and removal of the mask, significant leaks of anesthesia gas occur, which significantly contaminate the operating room.

BRIEF DESCRIPTION OF THE INVENTION It is therefore an object of the present invention to overcome the above disadvantages and to provide a single breath induction anesthesia apparatus that readily allows the pre-oxygenation of the patient and the unique breath induction anesthesia thereof, without causing contamination of an operating room with anesthetic gas.

According to the invention, a single breath induction anesthesia apparatus for anaesthetising a patient is provided, comprising a gas supply means for delivering at least one gas to the patient, and an oxygen delivery system for the patient. providing oxygen and an anesthesia oxygen / gas supply system for mixing oxygen and at least one anesthesia gas at an optimum pre-set rate to induce anesthesia of the patient with a single breath, thus providing a mixture of oxygen and anesthetic gas. The apparatus of the invention further includes a valve for providing selective gas flow communication between the oxygen supply system and the gas supply means between the anesthetic oxygen / gas supply system and the gas supply means. The valve is operable to first establish gas flow communication between the oxygen supply system and the gas supply means to supply oxygen to the patient and allow pre-oxygenation thereof., while inhibiting the gas flow communication between the anesthetic oxygen / gas supply system and the gas supply medium to allow the oxygen and gas anesthesia mixture to reach the pre-established optimal ratio, and therefore establish the communication of gas flow between the anesthetic oxygen / gas supply system and the gas supply means to supply the anesthetic oxygen / gas mixture to the patient and allow anesthesia to induce unique breath breath, while inhibiting the communication of gas flow between the oxygen supply system and the gas supply medium.

According to a preferred embodiment, the valve comprises a valve body having a first orifice in gas flow communication with the delivery system. of oxygen, a second orifice in gas flow communication with the anesthesia oxygen / gas supply system and a third orifice in gas flow communication with the gas supply means, and a valve member within the body of valve. The valve member is movable between a first position in which the first hole is in gas flow communication with the third hole and the second hole is closed, and a second position in which the first hole is closed and the second Orifice is in gas flow communication with the third hole. Preferably, the valve body has tubular branches, first, second and third, the holes, first, second and third, being defined at the respective proximal ends of the tubular branches, first, second and third, respectively. According to another preferred embodiment, the holes, second and third, are generally placed along a first axis and the first hole is generally positioned along a second axis extending transversely of the first axis. The tubular branches, second and third, extend along the first axis and the first tubular branch extends along the second axis. In such an embodiment, the valve member preferably has a T-shaped gas passage formed therein. According to a further preferred embodiment, the holes, first and second, are generally placed along a first axis and the third hole is generally positioned along a second axis extending transversely of the first axis. The tubular branches, first and second, extend along the first axis and the third tubular branch extends along the second axis. In such an embodiment, the valve member is preferably rotatably mounted on the valve body for movement about an axis of rotation that is co-axial with the second axis. According to still another preferred embodiment, the valve includes a stopping means for stopping the movement of the valve member in each of the first and second positions. Preferably, the stopping means comprises cooperative contact means placed on the valve member and the valve body. According to yet another preferred embodiment, the first tubular branch is provided with a gas venting means for venting excess oxygen, or venting exhaled gases by the patient during pre-oxygenation when the valve member is in the first position. The first tubular branch preferably comprises a first tubular section and a second tubular section which is removably connected to the first tubular section by means of a bayonet-type closing mechanism. Preferably, the second tubular section is provided with a gas outlet having a gas vent hole defining the gas venting means. In this way, when the pre-oxygenation of the patient has been contemplated, the second tubular section to which the oxygen supply system is connected can be disconnected from the first tubular section and removed. Due to the condition of the aforementioned valve allowing the communication of selective gas flow between the oxygen supply system and the gas supply means or between the oxygen / gas supply system of anesthesia and the delivery means of gas, the apparatus according to the invention allows the pre-oxygenation of a patient and the single-breath induction anesthesia thereof, without causing contamination of the operating room with the anesthetic gas. Therefore, the present invention provides, in another aspect thereof, a single breath induction anesthesia valve adapted to be used with the gas supply means to supply at least one gas to the patient, with an oxygen supply system to provide oxygen and with an oxygen / gas supply system of anesthesia to provide a mixture of oxygen-containing gas and at least one anesthesia gas in an optimum proportion preset enough to induce anesthesia of the patient with a single breath. The valve according to the invention comprises a valve body having a first orifice adapted to be in gas flow communication with the oxygen supply system, a second orifice adapted to be in gas flow communication with the oxygen system. oxygen supply / anesthetic gas and a third orifice adapted to be in gas flow communication with the gas supply means, and a valve member within the valve body. The valve member is movable between a first position in which the first hole is in gas flow communication with the third? >; and the second orifice is closed, whereby the oxygen supply to the patient and the pre-oxygenation thereof is allowed, and a second position in which the first orifice is closed and the second orifice is in gas flow communication with the third hole, whereby the supply of the oxygen / anesthetic gas mixture to the patient and the unique breath induction anesthesia thereof is allowed.

BRIEF DESCRIPTION OF THE DRAWINGS The features and advantages of the invention will be more readily apparent from the following description of the preferred embodiments thereof as illustrated by way of example in the accompanying drawings, in which: Figure 1 illustrates schematically a single breath induction anesthesia apparatus according to a preferred embodiment of the invention; Figure 2 is a partial top view of the apparatus illustrated in Figure 1, showing the valve with the valve member thereof in a first position; Figure 3 is another partial top view of the apparatus illustrated in Figure 1, showing the valve with the valve member thereof in a second position; Figure 4 is a partial side view of a single breath induction anesthesia apparatus according to another preferred embodiment of the invention, showing the valve with the valve member thereof in a first position; Figure 5 is a view similar to Figure 3, but showing the valve with the valve member thereof in a second position; Figure 6 is an exploded perspective view of the valve illustrated in Figure 4; Figure 7 is an exploded perspective view of the valve illustrated in Figure 5 and shown with a safety cap; and Figure 8 is a perspective view of the valve illustrated in Figure 7, showing the safety cap installed on the valve member.

MODES FOR CARRYING OUT THE INVENTION Referring first to Figure 1, a single-breath induction anesthesia apparatus is illustrated which is generally designed by reference number 10 and is seen to comprise a gas supply system 12 for delivering at least one gas to a patient (not shown), an oxygen delivery system 14, an anesthesia gas / oxygen delivery system 16 and a valve 18 to provide selective gas flow communication between the oxygen delivery system 14 and the gas supply system 12 or between the anesthesia oxygen / gas supply system 16 and the gas supply system 12. The gas supply system 12 comprises a connector tube 20 defining a bent tube and a mask 22 connected the same. The oxygen supply system 14 comprises an oxygen source 24 and an oxygen bag 26 which defines an oxygen container. The anesthesia oxygen / gas supply system 16, on the other hand, includes an oxygen / anesthesia gas source circuit 28 and a breathing circuit 30 in gas flow communication with each other. The anesthesia gas / oxygen source circuit 28 comprises an oxygen source 32 for supplying oxygen flowing through line 34 provided with a valve 36 and a flow meter (not shown), a source of nitrous oxide 38 for supplying nitrous oxide flowing through line 40 provided with a valve 42 and a flow meter (not shown), lines 34 and 40 emerging on line 44, and a vaporizer 46 which is connected to track 44 and mixing the oxygen and nitrous oxide with an anesthetic gas such as a sevoflurane at an optimum preset ratio sufficient to induce the patient's anesthesia with a single breath. Nitrous oxide is another anesthetic gas that increases the anesthetic effect of sevoflurane. The vaporizer is controlled to provide a mixture containing oxygen, nitrous oxide and sevoflurane in which sevoflurane is present at a concentration of about 8 vol.%. The breathing circuit 30 which is in gas flow communication with the oxygen source / anesthesia gas circuit 28 through the line 48 comprises a Y-shaped conduit 50 and a carbon dioxide absorber 52 connected to the same, the Y-shaped conduit 50 comprising three conduit sections 54, 56 and 58. The conduit sections 56 and 58 are provided with one-way valves (not shown) to direct the flow of gases exhaled by the patient to through an expiration duct section 56 along the direction indicated by the arrow 60 and through the suction duct section 58 along the direction indicated by the arrow 62. In this wayWhen the valve 18 is operated to establish the gas flow communication between the anesthesia oxygen / gas supply system 16 and the gas supply system 12, the gases inhaled and exhaled by the patient pass through the system. gas supply 12 and valve 18 and circulate through the breathing circuit 30. The carbon dioxide absorber 52 absorbs carbon dioxide from the gases exhaled by the patient, thus allowing the oxygen / anesthetic gas mixture to be absorbed. return to the patient with less carbon dioxide. As shown in Figures 2 and 3, valve 18 is a manually operated two-way valve comprising a generally T-shaped valve body 64 having three tubular branches 66, 68 and 70 with holes 72, 74 and 76 defined at the respective proximal ends of the tubular branches 66, 68 and 70, respectively, and a valve member 78 installed within the valve body 64 at the intersection of the tubular branches 66, 68 and 70. The valve member 78 has a T-shaped gas passage 80 formed therein and movable between a first portion shown in Figure 2, in which the orifice 72 is in gas flow communication with the hole 76 and the orifice 74 is closed , and a second position shown in Figure 3, in which the orifice 74 is closed and the orifice 74 is in gas flow communication with the orifice 76. A handle 84 is provided to manually move the valve member. the 78 between these two positions. The valve body 64 has a cylindrical portion 84 provided with a curved cut 86 defining at the longitudinal ends thereof two contact surfaces 88 (shown in Figure 3) and 90 (shown in Figure 2). The valve member 78, on the other side, is provided with a curved stopping member 92 extending in the cut 86 and having two contact surfaces 94 (shown in Figure 3) and 96 (shown in Figure 2). ). The contact surfaces 88 and 94 cooperate with each other to stop movement of the valve member 78 in the first position, while the contact surfaces 90 and 96 cooperate with each other to stop movement of the valve member 78 in the second position. The tubular branch 66 has a gas inlet 98 connected by means of a conduit 100 to the oxygen source shown in Figure 1, to provide gas flow communication between the orifice 72 and the oxygen source 24. The tubular branch 66 it is also connected at its distal end to the oxygen receiving bag 26 to provide gas flow communication between the orifice 72 and the oxygen receiving bag 26. The tubular branch 66 is also provided with a gas outlet 102 having an orifice of gas venting 104 to vent excess oxygen, or venting gases exhaled by the patient when valve member 78 is in the first position. The tubular branch 68 is connected to the duct section 54 of the Y-shaped conduit 50 to provide gas flow communication between the orifice 74 and the anesthetic oxygen / gas supply system 16. Such a tubular branch is provided with a gas outlet 106 having a gas discharge orifice 108 in gas flow communication with the orifice 74. The gas outlet 106 is connected via a conduit 1 10 to a gas analyzer 12 (shown in the Figure) 1) to provide gas flow communication between the orifice 74 and the gas analyzer 112 to allow gas analysis of the anesthetic oxygen / gas mixture. The tubular branch 70 is connected to the tube 20 to provide gas flow communication between the orifice 76 and the gas supply system 12. The tubular branches 66, 68 and 70 each have a circular cross section with diameters, inside and outside , selected so that the tubular branch 66 can be adjusted to any oxygen receiving bag 26, the tubular branch 68 to any standard breathing circuit 30 and the tubular branch 70 to any standard gas supply system 12. In operation, the mask 22 is fixed to the patient with the valve member 78 of the valve 18 meeting at the position shown in Figure 2. In this position of the valve member 78, the orifice 72 is in gas flow communication with the hole 76 and the orifice 74 closes. The oxygen source 24 is opened to allow oxygen to flow through the conduit 100, the gas inlet 98, the valve 18 along the direction indicated by the arrow 1 14 and the gas supply system 12, the oxygen also fills the receiving bag 26.

This allows a pre-oxygenation of the patient. The oxygen receiving bag 26 allows the patient to inhale a large volume of oxygen. At the same time, valves 36 and 42 are opened to allow oxygen and nitrous oxide to flow through lines 34, 40, 44 from oxygen and nitrous oxide sources 32, 38 to vaporizer 46 where oxygen and oxygen are present. Nitrous oxide is mixed with the sevoflurane contained in the vaporizer 46, the resulting gas mixture flowing from the vaporizer 46 to the breathing circuit 30 through the line 48. When the sevoflurane has reached the desired concentration indicated by the gas analyzer 1 12, the valve member 78 of the valve 18 is moved to the position shown in Figure 3. In this position of the valve member 78, the orifice 72 is closed and the orifice 74 is in gas flow communication with the valve. orifice 76. The anesthetic oxygen / gas mixture thus flows from the anesthesia oxygen / gas supply system 16 through the valve 18 along the direction indicated by arrow 1 16 and the delivery system. 12. This allows anesthesia to induce the patient's unique breath. The excess oxygen is vented through the gas vent hole 104. The valves 36 and 42 can then be partially closed to reduce the flow of oxygen and nitrous oxide. Instead of using sevoflurane, it is possible to use any other type of anesthetic gas available in the market. The optimal concentration of anesthesia sufficient to cause the anesthesia of a patient with a single breath can of course vary depending on the patient and the type of anesthetic gas used. The use of nitrous oxide is also optional.

Although a recirculatory type breathing circuit 30 has been illustrated, it is possible to use other types of breathing circuits or systems, such as Mapleson systems, including Bain and Ayers T systems. The apparatus illustrated in Figures 4 and 5 is similar to the apparatus shown in Figures 1-3, with the exception that the apparatus of Figures 4 and 5 comprise a valve 118 of different construction. As best shown in Figures 6 and 7, valve 118 is a manually operated two-way valve comprising a generally T-shaped valve body having a hollow cylindrical portion 122 and three tubular branches 124, 126 and 128 with holes 130, 132 and 134 defined at the respective proximal ends of the tubular branches 124, 126 and 128, and a valve member 136 installed in the cylindrical portion 122 of the valve body 120. The tubular branches 124 and 126 extend as far as possible. along a common axis 138, while the tubular branch 128 extends along a longitudinal axis 140 which is positioned at the right angle relative to the axis 138. The valve member 136 has a tubular portion 142 of cylindrical cross-section which defines an interior gas chamber 144 in gas flow communication with the orifice 134, and an upper portion 164 placed on the tubular portion 142, the upper portion 1 46 being provided with a handle 148. The tubular portion 142 has an opening 150 formed therein. The cylindrical portion 122 of the valve body 120 receives the tubular portion 142 of the valve member 136. The valve member 136 is removably mounted to the cylindrical portion 122 of the valve body 120 by means of a projection 152 extending around it. of the outer periphery of the tubular portion 142 of the valve member 136 and engaging a circumferential groove 154 formed in the inner surface of the cylindrical portion 122. The valve member 136 is also rotatably mounted in the latter for movement about of a rotation axis coaxial with the shaft 140, between a first position shown in Figures 4 and 6, in which the gas chamber 144 is in gas flow communication through the opening 150 with the hole 130 and the hole 132 closes, and a second position shown in Figures 5 and 7, in which the gas chamber 144 is in gas flow communication through the opening 150 with the hole 132 and the hole 130 is closed. In this way, when the valve member 136 is in the first position, the hole 130 is in gas flow communication with the hole 134 and, when the valve member 136 is in the second position, the orifice 132 it is in gas flow communication with the orifice 134. The handle 148 allows one to manually move the valve member 136 between these two positions. In order to stop the movement of the valve member 136 in each of the two previous positions, the cylindrical portion 122 of the valve body 120 has at one end thereof a radially elongated section 156 defining a curved channel 158 with two surfaces contact 160 and 162 (shown in Figure 7) at longitudinal ends of channel 158. Tubular portion 142 of valve member 136, on the other side, is provided with a stop member -164 extending into the channel 158 and having two contact surfaces 166 and 168. The contact surfaces 160 and 166 cooperate with each other to stop movement of the valve member 136 in the first position, while the contact surfaces 162 and 168 cooperate with each other to stop the movement of the valve member 136 in the second position. The section 156 is provided with two inwardly extending projections, small 170 and 172 on which the stop member 164 passes when the valve member 136 moves toward the first or second position so that the contact surface 166 or 168 engages the contact surface 160 or 172 in an interrupting action. The tubular branch 124 comprises a tubular section 124A which is fixed to the cylindrical portion 122 of the valve body 120 and a tubular section 124B which is removably connected to the tubular section 124A by means of a bayonet-type closing mechanism. Such a mechanism comprises a locking pin 174 extending outward from the tubular section 124A at the distal end thereof and an L-shaped groove 176 formed in the tubular section 124B at one end thereof and receiving the pin. of closure 174 in releasable closing clutch. The L-shaped groove 176 has a longitudinally extending groove portion 178 of the tubular section 124B and the groove portion 180 extending in the right angle relative to the groove portion 178. When the tubular sections 124A and 124B are connected together, the locking bolt 174 is placed in the slot portion 180 in the closed position shown in Figure 8. The tubular section 124B is provided at the ends thereof with two collars 182 and 184 integrally formed with it, the collar 182 partially covering the slot portion 178. The tubular section 124B has a gas inlet 186 connected via conduit 100 to the oxygen source 24 shown in Figure 1, to provide gas flow communication between the hole 130 and the oxygen source 24. Since the slot portion 180 of the L-shaped slot 176 extends in a direction opposite to the direction in which the gas inlet 186 s e extends, the weight of the gas inlet 186 and the duct 100 deflects the closure pin 174 in the slot portion 180 to the closed position shown in Figure 8. The tubular section 124B also connects at its distal end to an oxygen receiving bag 26 'for providing gas flow communication between the orifice 130 and the oxygen receiving bag 26'. The bag 26 'which also serves as an oxygen breathing bag has a tubular portion 188 provided with sleeves, inner and outer, 190 and 192 made of a resilient material such as rubber. The sleeve 190 is placed around the collar 184 in a gas-tight clutch therewith. The tubular section 124B is provided with a gas outlet 194 having a gas vent 196 (shown in Figures 6-8) to vent excess oxygen, or venting the gases exhaled by the patient when the valve member 136 is in the first position. The tubular branch 126 is connected to the duct section 54 'of a Y-shaped duct 50' which is similar to that of the Y-shaped duct 50 shown in Figure 1, to provide gas flow communication between the port 132 and the anesthesia gas / oxygen gas supply system 16 (shown in Figure 1). The conduit sections 56 'and' 58 'of the Y-shaped conduit 50' are connected to the carbon dioxide absorber 52. As in the case of conduit sections 56 and 58, conduit sections 56 'and 58' is provided with one-way valves (not shown) to direct the flow of gases exhaled by the patient through the expiratory conduit section 56 'along the direction indicated by the arrow 60 (shown in Figure 1) and through the suction duct section 58 'along the direction indicated by the arrow 62 (also shown in Figure 1). The tubular branch 126 is provided with a gas outlet 194 having a gas discharge orifice 196 in gas flow communication with the orifice 132. The gas outlet 194 is connected by means of a conduit 110 'which is similar to the conduit 110 shown in Figure 1 to gas analyzer 112 (shown in Figure 1), to provide gas flow communication between orifice 132 and gas analyzer 1 12 to allow gas analysis of the oxygen mixture / anesthesia gas. The duct 110 'extends through a cover 198 which is removably connected to the gas outlet 194 by means of a Luer lock type coupling system. The tubular branch 128 is directly connected to a mask 22 'to provide gas flow communication between the orifice 134 and the mask 22'. The mask 22 'has a frusto-conical portion 202 provided with a padded projection 204.

The apparatus shown in Figures 4 and 5 is operated in essentially the same manner as the apparatus shown in Figure 1.

During pre-oxygenation of the patient, valve member 136 of valve 118 is in the position shown in Figures 4 and 6. In this position of valve member 136, port 130 is in gas flow communication with the hole 134 and the hole 132 is closed. In this manner, oxygen flows from the oxygen source (shown in Figure 1) through line 100, gas inlet 186, valve 1 18 along the direction indicated by arrow 206 and mask 22 ', the oxygen also filling the receiving bag 26'. After the pre-oxygenation has been effected, the valve member 136 of the valve 118 is moved to the position shown in Figures 5 and 6, and the tubular section 124B is disconnected from the tubular section 124A and removed. In this position of the valve member 136, the orifice 130 closes and the orifice 132 is in gas flow communication with the orifice 134. In this manner, the oxygen / anesthetic gas mixture flows from the gas supply system. oxygen / anesthesia gas 16 (shown in Figure 1) through valve 118 along the direction indicated by arrow 208 and mask 22 ', causing the patient's unique breath induction anesthesia. Handle 148 is in the shape of an arrow indicating the direction of gas flow. As during the movement of the valve member 136 from the position shown in Figures 4 and 6 to the position shown in Figures 5 and 7, the valve member 136 moves about an axis of rotation that is coaxial with the shaft longitudinal 140 of the tubular branch 128, the pressure exerted on the valve member 136 for rotations thereof contributes to providing a gas-tight seal between the cushioned projection 204 of the mask 22 'and the patient's face. In order to releasably close the valve member 136 in the position shown in Figures 5 and 7, after a ventilation and endotracheal intubation has been performed, use is made of a safety cap 210 shown in Figures 7 and 8. The safety cap 210 comprises a dome-shaped rim 212, a hollow handle 214 extending outward from the rim 212 and a curved rim flange 216 depending on the rim 212. The safety cap 210 is adapted to fit removably on top portion 146 and handle 148 of valve member 136 with closure flange 216 extending into channel 158 to prevent displacement of stop member 164 when valve member 136 is in the position shown in FIG. Figures 5 and 7. Figure 8 shows the safety cover 210 installed on the valve member 136 and releasably closing it. In order to prevent the closure flange 216 from accessing the channel 158 when the valve member is in the position shown in Figures 4 and 6, the valve member 136 is provided with a curved projection 218 extending radially toward out from the tubular portion 142 of the valve member 136 and positioned adjacent the upper portion 146 thereof. The projection 218 extends over the channel 158 when the valve member is in the position shown in Figures 4 and 6 and thus acts as a shield preventing the closure flange 216 from being inserted into the channel 158.

Claims

CLAIMS 1. A single breath induction anesthesia apparatus for anesthetizing a patient, comprising: - a gas supply means adapted to be fixed to the patient to deliver at least one gas to the patient; - an oxygen supply system to provide oxygen; - an anesthesia oxygen / gas supply system for mixing oxygen and at least one anesthesia gas at an optimum pre-set rate to induce anesthesia of the patient with a single breath, thus providing a mixture of oxygen and anesthetic gas; and - a valve directly connected to said gas supply means for providing selective gas flow communication between said oxygen supply system and said gas supply means or between said oxygen supply / anesthesia gas system and said means of gas supply, said valve including a valve member movable between a first position in which said oxygen supply system and said gas supply means are in gas flow communication to supply oxygen to the patient and allow the -oxygenating the same, while simultaneously inhibiting gas flow communication between said anesthetic oxygen / gas supply system and said gas supply means to allow the oxygen / anesthetic gas mixture to reach said optimum proportion pre-established in said gas supply means, and a second position, in which said oxygen supply system / anesthesia gas and said gas supply means are in gas flow communication to supply said oxygen / anesthetic gas mixture in said optimum provides preset to the patient and allow anesthesia to induce unique breath thereof while inhibiting the communication of gas flow between said oxygen supply system and said gas supply means. An apparatus according to claim 1, characterized in that said valve comprises a valve body having a first orifice in gas flow communication with said oxygen supply system, a second orifice in gas flow communication with said system of oxygen supply / anesthesia gas and a third orifice in gas flow communication with said gas supply means, said valve member being received within said valve body, and wherein said valve member adds said first position, said first orifice is in gas flow communication with said third orifice and said second orifice is closed, while when said valve member assumes said second position, said first orifice is closed and said second orifice is in gas flow communication with said third hole. An apparatus according to claim 2, characterized in that said valve includes stop means for stopping the movement of said valve member in each of said first and second positions. An apparatus according to claim 3, characterized in that said stopping means each comprise cooperative contact means placed on said valve member and said valve body. An apparatus according to claim 3, characterized in that said valve member is provided with a handle for manually moving said valve member between said first and second positions. An apparatus according to claim 2, characterized in that said anesthesia gas / oxygen supply system includes a breathing circuit for collecting and recirculating the gases exhaled by the patient, whereas when said valve member is in said second position the gases inhaled and exhaled by said patient pass through said gas supply and shower valve system and circulate through said breathing circuit. 7. An apparatus according to claim 6, characterized in that said breathing circuit is provided with a carbon dioxide absorber for absorbing the carbon dioxide from the gases exhaled by the patient, thus allowing said oxygen / anesthetic gas mixture to be returned to said patient with less oxygen. carbon. An apparatus according to claim 2, characterized in that said valve body has first, second and third tubular branches and wherein said first, second and third orifices are defined at respective proximal ends of said first, second and third branches, respectively. An apparatus according to claim 8, characterized in that said holes, second and third, are placed along a first axis and said first hole is positioned along said second axis extending transversely of said first axis, and wherein said tubular branches, second and third, extend along said first axis and said first tubular branch extends along said second axis. An apparatus according to claim 9, characterized in that said valve member has a generally T-shaped gas passage formed therein. An apparatus according to claim 8, characterized in that said oxygen supply system includes an oxygen source and wherein said first tubular branch has a gas inlet connected to said gas source to provide gas flow communication between said first hole and said oxygen source. An apparatus according to claim 1, characterized in that said oxygen supply system further includes an oxygen container and wherein said first tubular branch is connected to said oxygen container to provide gas flow communication between said first orifice and said oxygen container. An apparatus according to claim 12, characterized in that said gas inlet is positioned between the proximal end of said first tubular branch and a distal end thereof, and wherein said oxygen container is connected to the distal end of said first branch. tubular. An apparatus according to claim 8, characterized in that said first tubular branch is provided with a gas venting means for venting the excess oxygen, or venting the gases exhaled by the patient when said valve member is in said first position . 15. An apparatus according to claim 14, characterized in that said first tubular branch is provided with a gas outlet having a gas vent hole defining said gas venting means. 16. An apparatus according to claim 8, characterized in that said second tubular branch has a gas outlet connected to a gas analyzer to provide gas flow communication between said second orifice and said gas analyzer to allow gas analysis of said gas analyzer. oxygen / anesthesia gas mixture. An apparatus according to claim 8, characterized in that said first and second holes are positioned along a first axis and said third hole is positioned along a second axis extending transversely of said first axis, and wherein said branches, first and second, extend along said first axis and said third tubular branch extends along said second axis. An apparatus according to claim 17, characterized in that said oxygen supply system includes an oxygen source and wherein said first tubular branch has a gas inlet connected to said oxygen source to provide gas flow communication between said first hole and said oxygen source. 19. An apparatus according to claim 1, characterized in that said oxygen delivery system further includes an oxygen container and wherein said first tubular branch is connected to said oxygen container to provide gas flow communication between said first orifice and said oxygen container. oxygen. 20. An apparatus according to claim 19, characterized in that said gas inlet is positioned between the proximal end of said first tubular branch and a distal end thereof; and wherein said oxygen container is connected to the distal end of said first tubular branch. An apparatus according to claim 20, characterized in that said first tubular branch comprises a first tubular section and a second tubular section removably connected at one end thereof to said first tubular section, and wherein said second tubular section is provided with said gas inlet and having an end opposite said end defining said distal end of said first tubular branch. 22. An apparatus according to claim 21, characterized in that said second tubular section is removably connected to said first tubular section by means of a bayonet-type closing mechanism. 23. An apparatus according to claim 22, characterized in that said bayonet closing mechanism comprises a locking bolt extending outward from said first tubular section at a distal end thereof and an L-shaped groove formed therein. second tubular section at said end thereof and receiving said locking bolt in releasable closing clutch. An apparatus according to claim 23, characterized in that said gas inlet extends outwardly from said second tubular section in a first direction, and wherein said L-shaped slot has a first longitudinally extending slot portion of said second tubular section and a second slot portion extending transversely of said first slot portion in the second direction opposite said first direction, whereby said closing bolt is biased to a closing position in said second slot portion. An apparatus according to claim 21, characterized in that said second tubular section is provided with a gas venting means for venting excess oxygen, or venting exhaled gases by the patient when said valve member is in said first position . 26. An apparatus according to claim 25, characterized in that said second tubular section is provided with a gas outlet having a vent hole defining said gas venting means. 27. An apparatus according to claim 17, characterized in that said second tubular branch has a gas outlet connected to a gas analyzer to provide the gas flow communication between said second orifice and said gas analyzer to allow gas analysis of the gas. said oxygen / anesthesia gas mixture. 28. An apparatus according to claim 17, characterized in that said valve member is mounted rotatably on said valve body for movement about an axis of rotation coaxial with said second axis. 29. An apparatus according to claim 28, characterized in that said valve member is removably mounted in said valve body. 30. An apparatus according to claim 28, characterized in that said valve member has a tubular portion of cylindrical cross-section defining an interior gas chamber in gas flow communication with said third orifice, said tubular portion having an opening formed in the same and providing communication of gas flow between said gas chamber and said first orifice when said valve member is in said first position, and communication of gas flow between said gas chamber and said second orifice when said valve member is Encentra in said second position, and wherein said valve body has a cylindrical portion that receives the tubular portion of said valve member. 31. An apparatus according to claim 30, characterized in that said valve includes stop means for stopping the movement of said valve member in each of said first and second positions. 32. An apparatus according to claim 31, characterized in that said valve member is provided with a handle for manually moving said valve member between said first and second positions. 33. An apparatus according to claim 31, characterized in that said stopping means each comprise cooperative contact means placed in the tubular portion of said valve member and in the cylindrical portion of said valve body. 34. An apparatus according to claim 33, characterized in that the cylindrical portion of said valve body has at one end thereof a radially elongated section defining a curved channel with contact surfaces, first and second, at longitudinal ends of said channel. , and wherein the tubular portion of said valve member is provided with a stop member extending in said channel and moving therein while moving the valve member, said stop member having contact surfaces, third and fourth cooperating respectively with said contact surfaces, first and second, to stop the movement of said valve member in each of said positions, first and second, said first, second, third and fourth contact surfaces defining said contact means . 35. An apparatus according to claim 34, characterized in that said valve includes safety means for releasably closing said valve member in said second position. 36. An apparatus according to claim 35, characterized in that said valve member has a top portion positioned on said tubular portion, and wherein said safety means comprises a safety cap having a curved closure flange and adapted to conform to removibie manner on the upper portion of said valve member with said closing flange extending in said channel to prevent the displacement of said stop member when said valve member is in said second position. 37. An apparatus according to claim 36, characterized in that said valve member is provided with protection means to prevent said closing flange having access to said channel when said valve member is in said first position. 38. An apparatus according to claim 37, characterized in that said protection means comprises a curved projection extending radially outwardly from the tubular portion of said valve member and positioned adjacent to the upper portion thereof, said projection extending over said portion. channel when said valve member is in said first position. 39. An apparatus according to claim 1, characterized in that said anesthetic gas is sevoflurane. 40. An apparatus according to claim 39, characterized in that said oxygen / anesthesia gas mixture in said preset optimum ratio contains sevoflurane in a concentration of about 8 vol%. 41. An apparatus according to claim 1, characterized in that said anesthetic oxygen / gas supply system comprises an oxygen source, a sevoflurane source and a nitrous oxide source, and is adapted to provide an oxygen containing mixture, sevoflurane and nitrous oxide in which sevoflurane is present in a concentration of about 8 vol.%. 42. A single breath induction anesthesia valve to be used with gas supply means to deliver at least one gas to a patient, with an oxygen delivery system to provide a gas mixture containing oxygen and at least one gas of anesthesia in an optimum proportion pre-established enough to induce the anesthesia of the patient with a unique breathsaid valve comprising a valve body having a first orifice adapted to be in gas flow communication with said oxygen supply system, a second orifice adapted to be in gas flow communication with said oxygen supply system / anesthesia gas and a third orifice adapted to be in gas flow communication with said gas supply means, and a valve member within said valve body, said valve member movable between a first position in which said first orifice is in gas flow communication with said third hole and said second orifice is closed, to allow thereby the supply of oxygen to the patient and the pre-oxygenation thereof, and a second position in which said first orifice is closes and said second orifice is in gas flow communication with said third orifice, to allow through which the supply or of the anesthetic oxygen / gas mixture to the patient and the single breath induction anesthesia thereof, wherein said first orifice is defined in a first tubular branch of said valve body, said first tubular branch comprising tubular sections, first and second, said tubular section connecting removably to said first tubular branch to allow the oxygen supply to disconnect from the valve body once the patient has been pre-oxygenated. 43. A valve according to claim 42, characterized in that it further includes stop means for stopping the movement of said valve member in each of said first and second positions. 44. A valve according to claim 43, characterized in that said stop means each comprise cooperative contact means placed in said valve member and said valve body. 45. A valve according to claim 43, characterized in that said valve member is provided with a handle for manually moving said valve member between said first and second positions. 46. A valve according to claim 42, characterized in that said valve body further includes tubular branches, second and third, and wherein said first, second and third holes are defined at respective proximal ends of said first, second and third tubular branches, respectively. 47. A valve according to claim 46, characterized in that said holes, second and third, are placed along a first axis and said first hole is placed along a second axis extending transversely of said first axis, and wherein said tubular branches, first and second, extend along said first axis and said first tubular branch extends along said second axis. 48. A valve according to claim 47, characterized in that said valve member has a generally T-shaped gas passage formed therein. 49. A valve according to claim 46, characterized in that said first tubular branch has a gas inlet adapted to be connected to an oxygen source of said oxygen supply system to provide the gas flow communication between said first orifice and said source. of oxygen. 50. A valve according to claim 49, characterized in that said first tubular branch is adapted to be connected to an oxygen container of the oxygen supply system to provide gas flow communication between said first orifice and said oxygen container. 51. A valve according to claim 49, characterized in that said gas inlet is positioned between the proximal end of said first tubular branch and a distal end thereof.; and wherein said first tubular branch is adapted to be connected at the distal end thereof to an oxygen container of the oxygen supply system to provide gas flow communication between said first orifice and the oxygen container. 52. A valve according to claim 46, characterized in that said first tubular branch is provided with gas venting means for venting excess oxygen, or venting exhaled gases by the patient when said valve member is in said first position. 53. A valve according to claim 52, characterized in that said first tubular branch is provided with a gas outlet having a gas vent hole defining said gas vent means. 54. A valve according to claim 46, characterized in that said second tubular branch has a gas outlet adapted to be connected to a gas analyzer to provide gas flow communication between said second orifice and said gas analyzer to w gas analysis of said oxygen / anesthesia gas mixture. 55. A valve according to claim 46, characterized in that said holes, first and second, are placed along a first axis and said third hole is placed along a second axis extending transversely of said first axis, and wherein said tubular branches, first and second, extend along said first axis and said third tubular branch extends along said second axis. 56. A valve according to claim 55, characterized in that said first tubular branch has a gas inlet adapted to be connected to an oxygen source of said oxygen supply system to provide gas flow communication between said first orifice and said source. of oxygen. 57. A valve according to claim 56, characterized in that said first tubular branch is adapted to be connected to an oxygen vessel of the oxygen supply system to provide gas flow communication between said first orifice and said oxygen vessel. 58. A valve according to claim 56, characterized in that said gas inlet is positioned between the proximal end of said first tubular branch and a distal end thereof, and wherein said first tubular branch is adapted to be connected to the distal end of the vessel. same to an oxygen container of the oxygen supply system to provide gas flow communication between said first hole and the oxygen container. 59. A valve according to claim 58, characterized in that said second tubular section is provided with said gas inlet and has an end opposite said end defining said distal end; of said first tubular branch. 60. A valve according to claim 59, characterized in that said second tubular section is removably connected to said first tubular section by means of a bayonet-type closing mechanism. 61. A valve according to claim 60, characterized in that said bayonet closing mechanism comprises a locking bolt extending outwardly from said first tubular section at a distal end thereof and an L-shaped groove formed therein. second tubular section at said end thereof and receiving said locking bolt in releasable closing clutch. 62. A valve according to claim 61, characterized in that said gas inlet extends outwardly from said second tubular section in a first direction, and wherein said L-shaped slot has a first longitudin extending slot portion of said second tubular section and a second slot portion extending transversely of said first slot portion in the second direction opposite said first direction, whereby said closing bolt is biased to a closing position in said second slot portion. 63. A valve according to claim 59, characterized in that said second tubular section is provided with gas venting means for venting excess oxygen, or venting gases exhaled by the patient when said valve member is in said first position. 64. A valve according to claim 63, characterized in that said second tubular section is provided with a gas outlet having a gas vent hole defining said gas venting means. 65. A valve according to claim 55, characterized in that said second tubular branch has a gas outlet connected to a gas analyzer to provide gas flow communication between said second orifice and said gas analyzer to allow gas analysis of said gas analyzer. oxygen / anesthesia gas mixture. 66. A valve according to claim 55, characterized in that said valve member is mounted rotatably on said valve body for movement about an axis of rotation coaxial with said second axis. 67. A valve according to claim 66, characterized in that said valve member is removably mounted in said valve body. 68. A valve according to claim 66, characterized in that said valve member has a tubular portion of cylindrical cross-section defining an interior gas chamber in gas flow communication with said third hole, said tubular portion having an opening formed in the same and that provides communication of gas flow between said gas chamber and said first orifice when said valve member is in said first position, and communication of gas flow between said gas chamber and said second orifice when said valve member it is in said second position, and wherein said valve body has a cylindrical portion that receives the tubular portion of said valve member. 69. A valve according to claim 68, characterized in that it further includes stop means for stopping the movement of said valve member in each of said first and second positions. 70. A valve according to claim 69, characterized in that said valve member is provided with a handle for manually moving said valve member between said first and second positions. 71. A valve according to claim 69, characterized in that said stopping means each comprise cooperative contact means placed in the tubular portion of said valve member and in the cylindrical portion of said valve body, 72. A valve according to claim 71, characterized in that the cylindrical portion of said valve body has at one end thereof a radially elongated section defining a curved channel with contact surfaces, first and second, at the longitudinal ends of said channel, and wherein the portion The tubular member of said valve member is proportioned with a stop member extending in said channel and moving therein when moving the valve member, said stop member having contact surfaces, third and fourth, cooperating respectively with said contact surfaces, first and second, to stop the movement of said valve member in each one of said positions, first and second, said first, second, third and fourth contact surfaces defining said contact means. 73. A valve according to claim 72, characterized in that said valve includes safety means for releasably closing said valve member in said second position. 74. A valve according to claim 73, characterized in that said valve member has an upper portion positioned on said tubular portion, and wherein said safety means comprises a safety cap having a curved closure flange and adapted to be adjusted removable on the upper portion of said valve member with said closing flange extending into said channel to prevent displacement of said stop member when said valve member is in said second position. 75. A valve according to claim 74, characterized in that said valve member is provided with protection means to prevent said closure flange having access to said channel when said valve member is in said first position. 76. A valve according to claim 75, characterized in that said protection means comprises a curved projection extending radially outwardly from the tubular portion of said valve member and positioned adjacent to the upper portion thereof, said projection extending over said channel when said valve member is in said first position. SUMMARY A single breath induction anesthesia apparatus (10) for anesthetizing a patient, comprises a gas delivery system (12) to deliver at least one gas to the patient, an oxygen delivery system (14) to provide oxygen , and an anesthesia oxygen / gas supply system (16) for mixing oxygen and at least one anesthesia gas at an optimum pre-set rate sufficient to cause anesthesia of the patient with a single breath, thus providing an oxygen / gas mixture of anesthesia. The apparatus (10) of the invention further includes a valve (18) for providing selective gas flow communication between the oxygen supply system (14) and the gas supply system (12) or between the gas supply system (12). oxygen / anesthetic gas (16) and the gas supply system (12). The valve (18) is operable to first establish gas flow communication between the oxygen supply system (14) and the gas supply system (12) to supply oxygen to the patient and allow pre-oxygenation thereof, while inhibits gas flow communication between the anesthetic oxygen / gas supply system (16) and the gas supply system (12) to allow the anesthetic oxygen / gas mixture to reach the preset optimal ratio, and establish thus communication of gas flow between the oxygen supply system / anesthesia gas (16) and the gas supply system (12) to supply the oxygen / anesthetic gas mixture to the patient and allow anesthesia of breath induction unique thereto, while inhibiting communication of gas flow between the oxygen supply system (14) and the gas supply system (12).