Abstract:
A gas supply apparatus is provided and has first and second fittings and first and second tubes. The first fitting is provided to discharge a gas of a first pressure therethrough, while the second fitting is provided to discharge a gas of a second pressure therethrough. The first tube has one end to which a first connector connectable to the first fitting is attached and supplies the first-pressure gas to a first body cavity of a subject. The second tube has one end to which a second connector connectable to the second fitting is attached and supplies the second-pressure gas to a second body cavity of the subject. The apparatus may comprise an erroneous-connection preventing device preventing an erroneous connection including at least one of a connection of the first connector to the second fitting and a further connection of the second connector to the first fitting.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   The present application relates to and incorporates by reference Japanese Patent applications No. 2004-97126 filed on Mar. 29, 2004 and No. 2005-82545 filed on Mar. 22, 2005. 
   BACKGROUND OF THE INVENTION 
   1. Technical Field of the Invention 
   The present invention relates to a gas supply apparatus for supplying a predetermined kind of gas (e.g., carbon dioxide gas) to body cavities of a subject to be medically treated, and more particularly, to a gas supply apparatus which supplies gas to different body cavities, such as an abdominal cavity and a luminal cavity, at different pressures, respectively. 
   2. Related Art 
   In recent years, laparoscopic surgeries are performed for curative treatment without opening an abdominal cavity, for the purpose of mitigating invasion on a subject to be examined. In a laparoscopic surgery, a first trocar for guiding an endoscope for observation and a second trocar for guiding a treatment tool to a site to be treated, for example, are punctured into an abdomen of a subject. Also, in a laparoscopic surgery, treatment or the like is performed observing both a site to be treated and a treatment tool that has been inserted through an insertion hole of the second trocar, by using an endoscope inserted into an abdominal cavity through an insertion hole of the first trocar. 
   In such a laparoscopic surgery, an abdominal insufflation apparatus is used for injecting carbon dioxide gas, for example, as an abdominal insufflation gas into an abdominal cavity for purposes of retaining a visual field for the endoscope and a space for manipulating the treatment tool. 
   For luminal cavities, such as a stomach and a large intestine, an endoscope and a treatment tool as mentioned above are also used for diagnosis and treatment. In effecting medical treatment, including diagnosis and treatment, in luminal cavities, such as a stomach and a large intestine by an endoscopic observation, a gas, such as air as a luminal cavity gas is injected into the luminal cavity for purposes of retaining a visual field for the endoscope and a space for manipulating the treatment tool. Air, which is generally supplied into a luminal cavity by a gas supply pump, may be replaced by carbon dioxide gas. 
   Recently, a new approach may be taken in a laparoscopic surgery by inserting an endoscope into a luminal cavity to internally and externally specify a site to be treated for effecting treatment. In this case as well, air, for example, may be supplied from an endoscope inserted into a luminal cavity to inflate the luminal cavity. 
   However, when air is supplied into a luminal cavity as described above, as air is less likely to be absorbed by a living organism, the luminal cavity may possibly remain being inflated and may make it difficult to retain a necessary space for laparoscopic surgery. Accordingly, there has been a need for use of an endoscope CO 2  regulator (hereinafter referred to as an ECR), a device for sending a gas such as carbon dioxide gas which is easily absorbed by living organisms, such as a large intestine. 
   However, arranging conventional surgical equipment for endoscopic surgery by providing an ECR, results in placing a set of the abdominal insufflation apparatus and a CO 2  container, separately from a set of the ECR and a CO 2  container. This results in increasing variety of pieces of peripheral medical equipment, which are to be accommodated in a plurality of carts, making movement a bothersome labor. 
   In the prior art equipment described above, two pieces of equipment, i.e. an abdominal insufflation apparatus and an ECR, have to be separately provided, which arises problems of cumbersome and complicated preparation and of spatial inefficiency. Further, when pieces of equipment are separately set up, erroneous connections tend to occur, e.g., connecting a luminal cavity tube to a supply fitting of an abdominal insufflation apparatus, or connecting an abdominal cavity tube to a supply fitting of an ECR. 
   SUMMARY OF THE INVENTION 
   The present invention has been made in light of the circumstances described above, and has as its object to provide a gas supply apparatus which enables correct and prompt connection of tubes to a fitting for supplying an abdominal cavity gas and a fitting for supplying a luminal cavity gas, whereby the gas can be correctly supplied. 
   One aspect of the present invention provides a gas supply apparatus comprising a first fitting through which a gas of a first pressure is discharged; a second fitting through which a gas of a second pressure is discharged; a first tube having one end to which a first connector connectable to the first fitting is attached and supplying the gas of the first pressure to a first body cavity of a subject to be medically treated; and a second tube having one end to which a second connector connectable to the second fitting is attached and supplying the gas of the second pressure to a second body cavity of the subject. 
   Favorably, there may be provided an erroneous-connection preventing device for preventing erroneous connection, i.e. connecting the first connector to the second fitting, and connecting the second connector to the first fitting. 
   More favorably, there may be provided: a single gas source for supplying a gas having the first and the second pressures; and a gas supply unit that controls pressure of the gas supplied from the gas source so as to supply the first pressure gas and the second pressure gas to the first and the second fittings, respectively. 
   In this connection, there may be further provided: for example, a sensor for detecting information on connecting state between the first connector and the first fitting, and between the second connector and the second fitting; a device for judging whether or not connection has been correctly made between the first connector and the first fitting, and between the second connector and the second fitting, based on the information from the sensor; and a gas supply control unit for controlling supply of the first pressure gas and the second pressure gas from the gas supply unit to the first and the second fittings, respectively, based on the results of judgment made by the judging device. 
   Another aspect of the present invention provides a method for managing connection of conduits in a gas supply apparatus comprising steps of: detecting a state of connection of a first conduit which is connected to a first fitting for discharging a gas having a first pressure, and a state of connection of a second conduit which is connected to a second fitting for discharging a gas having a second pressure; judging whether or not the first connector has been correctly connected to the first fitting, and whether or not the second connector has been correctly connected to the second fitting; giving a command to supply the first pressure gas to the first fitting upon judgment of correct connection as having made between the first connector and the first fitting and giving a command to stop supply of the first pressure gas to the first fitting upon judgment of erroneous connection as having made between the first connector and the first fitting; and giving a command to supply the second pressure gas to the second fitting upon judgment of correct connection as having made between the second connector and the second fitting and giving a command to stop supply of the second pressure gas to the second fitting upon judgment of erroneous connection as having made between the second connector and the second fitting. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the appended drawings: 
       FIG. 1  is a schematic diagram illustrating an endoscopic system including a first embodiment of a gas supply apparatus of the present invention; 
       FIG. 2  is a block diagram illustrating a configuration of a gas supply apparatus of the first embodiment; 
       FIG. 3  is an explanatory diagram illustrating an operation panel of a gas supply apparatus; 
       FIG. 4  is an explanatory diagram illustrating a display panel of a gas supply apparatus; 
       FIG. 5  is an explanatory diagram illustrating a front panel including a preset operation part and a display part; 
       FIG. 6A  is a perspective view of a front panel of a gas supply apparatus mounting gas supply fittings, and an abdominal cavity tube and a luminal cavity tube to be connected to the gas supply fittings, respectively; 
       FIG. 6B  is a sectional view showing a structure along a direction orthogonal to a longitudinal direction to illustrate a state of connection between an abdominal cavity fitting and a connector for an abdominal cavity tube; 
       FIG. 6C  is a sectional view showing a structure along a direction orthogonal to a longitudinal direction to illustrate a state of connection between a luminal cavity fitting and a connector for a luminal cavity tube; 
       FIG. 7A  is a perspective view of a front panel of a gas supply device mounting gas supply fittings, and an abdominal cavity tube and a luminal cavity tube to be connected to the gas supply fittings, respectively, according to a second embodiment of the gas supply apparatus of the present invention; 
       FIG. 7B  is a sectional view showing a structure along a direction orthogonal to a longitudinal direction of a connector for an abdominal cavity tube; 
       FIG. 7C  is a sectional view showing a structure along a direction orthogonal to a longitudinal direction of a connector for a luminal cavity tube; 
       FIG. 7D  is a sectional view showing a structure along a direction orthogonal to a longitudinal direction of a supply fitting for an abdominal cavity; 
       FIG. 7E  is a sectional view showing a structure along a direction orthogonal to a longitudinal direction of a supply fitting for a luminal cavity; 
       FIG. 8  is a block diagram illustrating a configuration of a second embodiment of a gas supply apparatus of the present invention; 
       FIG. 9  is a flowchart generally illustrating processes for making judgment of erroneous connection of a tube and for controlling gas supply based on the judgment, which are executed by a controller, according to the second embodiment; 
       FIG. 10A  is a perspective view of a front panel of a gas supply apparatus mounting gas supply fittings, and an abdominal cavity tube and a luminal cavity tube to be connected to the gas supply fittings, respectively, according to a third embodiment of the gas supply apparatus of the present invention; 
       FIG. 10B  is a sectional view showing a structure along a direction orthogonal to a longitudinal direction of a connector for of an abdominal cavity tube; 
       FIG. 10C  is a sectional view showing a structure along a direction orthogonal to a longitudinal direction of a connector for a luminal cavity tube; 
       FIG. 10D  is a sectional view showing a structure along a direction orthogonal to a longitudinal direction of a supply fitting for an abdominal cavity or a supply fitting for a luminal cavity; 
       FIG. 11  is a flowchart generally illustrating processes for making judgment of erroneous connection of a tube and for controlling gas supply based on the judgment, which are executed by a controller, according to the third embodiment; and 
       FIG. 12  is a flowchart generally illustrating processes for making judgment of erroneous connection of a tube and for controlling gas supply based on the judgment, which are executed by a controller, according to a fourth embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Embodiments of the present invention will now be described below with reference to the appended drawings. 
   First Embodiment 
   Referring to  FIGS. 1 to 6 , a first embodiment of a gas supply apparatus according to the present invention is described. 
     FIG. 1  shows an endoscopic system  1  to which the present embodiment of the gas supply apparatus according to the present invention is applied. As shown, the endoscopic system  1  has an endoscope  5  for performing endoscopy in an abdominal cavity of a subject  3  lying on an operating table  2 , with the endoscope  5  mounting a TV camera head  4  incorporating an imaging device. 
   As shown, a guide tube (trocar)  6  for performing abdominal insufflation by supplying carbon dioxide gas for retaining a visual field for the endoscope  5 , and a guide tube (trocar)  7  for inserting an electric cautery probe (not shown) for electrically performing cautery, are punctured into the abdominal cavity of the subject  3 . 
   A signal cable  8  is connected to the TV camera head  4 , and a light guide cable  9  is connected to the endoscope  5 . An abdominal insufflation tube (hereinafter referred to as an abdominal cavity tube)  10  is connected to the abdominal insufflation guide tube  6 , and a signal cable  11  is connected to the electric cautery probe (not shown) which is inserted into the electric cautery guide tube  7 . 
   The signal cable  8  and the light guide cable  9  are, respectively, connected to a camera control unit (hereinafter referred to as a CCU)  19  and a first light source device  20  which are both loaded on a trolley  18 . The abdominal cavity tube  10  is connected to a gas supply apparatus  21  serving as an abdominal insufflation apparatus, which is loaded on the trolley  18 . Further, the signal cable  11  is connected to an electric cautery device  23  loaded on the trolley  18 . 
   The endoscopic system  1  incorporating the present embodiment comprises an endoscope  12  for performing endoscopy in a luminal cavity, such as a large intestine of the subject  3 . The endoscope  12  is arranged such that a gas, such as carbon dioxide gas supplied through a gas supply conduit (not shown) in a universal code  17  can be supplied from a tip of an insert  16 , by pressing down a gas supply button  13   a  provided at an operating part  13  which is located at a rear end side of a handle  14 . 
   The universal code  17  comprises therein, although not shown, a signal cable, a light guide and the gas supply conduit, and is connected to a second light source device  24  loaded on the trolley  18  through a connector part  17 A. It is arranges such that the connector part  17 A has a carbon dioxide gas supply port  17   a  to which a luminal cavity tube  22  from the gas supply apparatus is connected and that carbon dioxide gas is supplied by the gas supply apparatus  21  through the carbonic gas supply port  17   a.    
   Loaded on the trolley  18  are the CCU  19  for processing signals for the imaging device, the first light source device  20  for providing illumination to the endoscope  5 , the gas supply apparatus  21  for supplying a gas (carbon dioxide gas) for use in an abdominal cavity and a luminal cavity, the electric cautery device  23  for feeding high-frequency power for enabling cautery, and the second light source device  24  for providing illumination to the endoscope  12 . The trolley  18  also carries thereon, a system controller  25  for performing general control, a CCU (camera control unit)  19 A which is connected to the second light source device  24  and used for the endoscope  12 , a VTR (not shown) for recording video signals from the CCUs  19  and  19 A, a monitor  26  for displaying the video signals, which are obtained from the CCUs  19  and  19 A via the system controller  25 , in the form of images, a carbon dioxide gas container (CO 2  container)  29  for supplying carbon dioxide gas to the gas supply apparatus  21  through a high pressure gas tube  29 A. 
   Further, a display panel  27  for performing display and a panel  28  for performing operation are attached to the trolley  18 . 
   The individual pieces of the medical equipment, such as the CCUs  19  and  19 A are connected to the system controller  25  through communication cables, not shown. The system controller  25  may be operated through the operation panel  28  of touch panel type or a remote controller, not shown. Further, indication for the system controller  25  is performed through the operation panel  28  or the display panel  27 . 
   The CCU  19  effects signal processing to the image signals from the endoscope  5  and supplies video signals based on the image signals to the system controller  25 , the monitor  26  and the VTR (not shown). 
   The CCU  19 A effects signal processing to the image signals from the endoscope  12  and supplies video signals based on the image signals to the system controller  25  and the VTR (not shown). 
   The first light source device  20  serves as a light source device for providing illumination through a light guide in the light guide cable  9  to an illumination optical system provided at the endoscope  5 . The second light source device  24  serves as a light source device for providing illumination through a light guide in the universal code  17  to an illumination optical system provided at the endoscope  12 . 
   The gas supply apparatus  21 , whose internal configuration is described later, is used for retaining a visual field for the endoscope  5  by supplying carbon dioxide gas into an abdominal cavity, for example, of a subject through the abdominal insufflation guide tube  6  connected thereto, and for retaining a visual field for the endoscope  12  by supplying carbon dioxide gas into a luminal cavity, for example, of a subject through the tip of the insert  16  of the endoscope  12  connected thereto. 
   A supply fitting  21 A for abdominal cavity to which the abdominal cavity tube  10  is connected, and a supply fitting  21 B for luminal cavity to which the luminal cavity tube  22  from the carbon dioxide gas supply port  17   a  is connected, are provided at a front panel FP of the gas supply apparatus  21  (see  FIG. 5 ). 
   The electric cautery device  23  serves as a surgical treatment tool for use in electro-thermal cutting process, for example, at an abnormal site within an abdominal area of a subject, and as a high-frequency output device for outputting a high-frequency current to the surgical treatment tool. 
   In the system controller  25  are provided an operation signal receiver for receiving a signal from the operation panel  28  and a preset operation part  41  (see  FIG. 2 ), as will be described hereinafter, for the gas supply apparatus  21 , an operation driver for transmitting information necessary for the operation panel  28  and for indication at a display  42  (see  FIG. 2 ) for the gas supply apparatus  21 . 
   The system controller  25  is electrically connected to a communication part, not shown, for performing communication with the pieces of medical equipment loaded on the trolley  18 . The communication part is so arranged as to be connected to the CCUs  19  and  19 A, the first light source device  20 , the gas supply apparatus  21 , the electric cautery device  23 , the second light source device  24 , and the VTR, not shown, through communication cables to enable two-way communication with these pieces of medical equipment. It should be noted that  FIG. 1  shows an arrangement wherein the gas supply apparatus  21  is connected to the system controller  25  through a connector cable  25 A. 
   In addition, the system controller  25  comprises therein a video signal processor (not shown), which is configured such that image signals from the CCUs  19  and  19 A may be processed to produce video signals for transmission to the monitor  26 . 
   The monitor  26  displays the video information, i.e. endoscopic images supplied from the system controller  25 . 
   A configuration of the gas supply apparatus  21  is described below with reference  FIG. 2 . 
   As shown in  FIG. 2 , the gas supply apparatus  21  comprises a high-pressure fitting  30 , a supply pressure sensor  31 , a pressure reducing device  32 , a first and second electropneumatic proportional valves  33  and  34 , a first and a second electromagnetic valves  35  and  36 , a pressure sensor  37 , a first and a second flow sensors  38  and  39 , a controller  40 , the preset operation part  41 , the display  42 , the abdominal cavity supply fitting  21 A having a first detector  21 A 1 , and a luminal cavity supply fitting  21 B having a second detector  21 B 1 . 
   The carbon dioxide gas container  29  and the gas supply apparatus  21  are linked through the high-pressure tube  29 A with one end of which being connected to the high-pressure fitting  30  provided at the gas supply apparatus  21 . 
   The signal cable  25 A extending from the system controller  25  is adapted to be detachably attached to an electric connector, not shown, of the gas supply apparatus  21  so as to be electrically connected to the controller  40  therein. 
   The other end (connector part) of the abdominal cavity tube  10  is adapted to be detachably attached to the abdominal cavity supply fitting  21 A which is provided at the gas supply apparatus  21 . Also, the other end (connector part) of the luminal cavity tube  22  is adapted to be detachably attached to the luminal cavity supply fitting  21 B which is provided at the gas supply apparatus  21 . 
   Liquid carbon dioxide stored in the carbon dioxide gas container  29  is gasified and led to the pressure reducing device  32  through an internal conduit inside the gas supply apparatus  21 . The carbon dioxide gas, after its pressure being reduced to a predetermined level by the pressure reducing device  32 , is led to the internal conduit which is formed into two systems, so that the pressure is adjusted by the first and the second electropneumatic proportional valves  33  and  34  in the systems to the levels suitable for use in the abdominal cavity and the luminal cavity, respectively. 
   The carbon dioxide gas for abdominal cavity which has been adjusted by the first electropneumatic proportional valve  33  is so arranged to be led into an abdominal cavity through the first electromagnetic valve  35 , the first flow sensor  38 , the abdominal cavity supply fitting  21 A, the abdominal cavity tube  10 , and a channel (gas supply conduit, not shown) provided in the abdominal insufflation guide tube  6 . 
   The carbon dioxide gas for the luminal cavity which has been adjusted by the second electropneumatic proportional valve  34  is so arranged to be led into a luminal cavity through the second electromagnetic valve  36 , the second flow sensor  39 , the luminal cavity supply fitting  21 B, the luminal cavity tube  22 , the connector part  17 A, the universal code  17 , and a channel (gas supply conduit, not shown) provided in the endoscope  12 . 
   The supply pressure sensor  31  measures the pressure of the carbon dioxide gas supplied from the carbon dioxide gas container  29  to output the measurement results to the controller  40 . The pressure reducing device  32  reduces the pressure of the carbon dioxide gas supplied from the carbon dioxide gas container  29  to a predetermined level for supply to the first electropneumatic proportional valve  33  and the second electropneumatic proportional valve  34 . 
   Pressure control by the first and the second electropneumatic proportional valves  33  and  34  is enabled by the controller  40 . Specifically, these valves adjust the pressure, which has been reduced by the pressure reducing device  32 , based on a control signal from the controller  40  so as to fall within a predetermined range. 
   For example, the first and the second electropneumatic proportional valves  33  and  34  can reduce the pressure of the carbon dioxide gas, which has been reduced by the pressure reducing device  32 , based on a control signal from the controller  40 , so as to fall within a range of 0-500 mmHg. 
   It should be noted that a range of a gas supply pressure suitable for an abdominal cavity may desirably be about 0-80 mmHg, and that a suitable range of a gas supply flow rate may desirably be about 0.1-35 L/min. Also, a range of a gas supply pressure suitable for a luminal cavity may desirably be about 0-500 mmHg, and that a suitable range of a gas supply flow rate may desirably be about 1-3 L/min. 
   The first and the second electromagnetic valves  35  and  36  are the valves whose opening and closing can be controlled by the controller  40 . Specifically, these valves are switched from an open state to a closed state, or vice versa, in response to a control signal from the controller  40 . 
   The pressure sensor  37  measures the pressure in an abdominal cavity when the first electromagnetic valve  35  is closed, and outputs the results of the measurement to the controller  40 . 
   The first flow sensor  38  measures the flow rate of carbon dioxide gas that flows in the internal conduit passing through the first electromagnetic valve  35 , and outputs the results of the measurement to the controller  40 . The second flow sensor  39  measures the flow rate of carbon dioxide gas that flows in the internal conduit passing through the second electromagnetic valve  36 , and outputs the results of the measurement to the controller  40 . 
   Although not shown, an exhaust valve may be provided between the first electromagnetic valve  35  and the first flow sensor  38 . When a measured value of the pressure sensor  37  exceeds a set pressure value of an abdominal cavity, the exhaust valve is adapted to be open in response to a signal from the controller  40  so that the pressure in the abdominal cavity is decreased, thereby allowing the carbon dioxide gas in the abdominal cavity to be discharged in the atmosphere. A similar pressure sensor and an exhaust valve may be provided on the side of an internal conduit for luminal cavity (i.e. between the second electromagnetic valve  36  and the second flow sensor  39 ). 
   The preset operation part  41 , which is described hereinafter, is connected to the controller  40 , so that the controller  40  can execute various controls in response to operation signals from the preset operation part  41 . The configuration of the front panel FP comprising the preset operation part  41  and the display  42  will be described later. 
     FIG. 3  shows an exemplary configuration of the operation panel  28  shown in  FIG. 1 . 
   As shown in  FIG. 3 , the operation panel  28  is provided with a preset operation button  28   a  for adjusting abdominal insufflation flow for an abdominal or luminal cavity caused by the gas supply apparatus (abdominal insufflation apparatus)  21 , an operation button  28   b  for adjusting an output of the electric cautery device (high-frequency combustion device)  23 , an operation button  28   c  for adjusting color tone of the CCUs  19  and  19 A, an operation button  28   d  for instructing change of display of video information to be displayed on the monitor  26 , an operation button  28   e  for instructing to stop recording of the VTR, and an operation button  28   f  for adjusting quantity of light of the first light source device  20  and the second light source device  24 . 
     FIG. 4  shows an example of the display panel  27  shown in  FIG. 1 . 
   As shown in  FIG. 4 , the display panel  27  is adapted to display, on display areas  27 A ( 27   a ,  27   b ),  27   c ,  27   d  and  27   e  of its display screen, setting and operational conditions with respect to the functions of the gas supply apparatus  21 , the electric cautery device  23 , a water supply/suction pump (not shown), the VTR (not shown), respectively, for example, whose communication is controlled by the system controller  25 . Note that the display area  27 A indicates the setting/operational conditions for the gas supply apparatus  21 , and includes the display area  27   a  for internal pressure of a luminal cavity and the display area  27   b  for internal pressure of an abdominal cavity, as well as a display area for residual quantity of carbon dioxide gas, and a display area for flow rate. 
   Next, an exemplary configuration of the preset operation part  41  and the display  42  provided at the front panel FP of the gas supply apparatus  21  is described below with reference to  FIG. 5 . 
   As shown in  FIG. 5 , the preset operation part  41  and the display  42  are provided at the front panel FP of the gas supply apparatus  21 . 
   The preset operation part  41  and the display  42  are partitioned into a preset display  21 C for preset, operation and display for the carbon dioxide container  29 , a preset display  21 D for preset, operation and display for an abdominal cavity, and a preset display  21 E for preset, operation and display for a luminal cavity. The abdominal cavity supply fitting  21 A is provided at a lower side of the preset display  21 D, and the luminal cavity supply fitting  21 B is provided at a lower side of the preset display  21 E. With such disposition and configuration, an operator can easily operate and easily view the gas supply apparatus  21 . 
   In the preset display  21 C, there are provided a residual gas quantity display  21   a  which is included in the display  42 , a gas supply start button  21   b , a gas supply stop button  21   c  and a power switch  21   d  which are included in the preset operation part  41 . 
   In the preset display  21 D, there are provided a display  21   e  for internal pressure of an abdominal cavity, a flow rate display  21   f , a total gas supply display  21   g  and a pressure warning lamp  2   h  which are included in the display  42 , and a preset button  21   i  for internal pressure of an abdominal cavity, a preset button  21   j  for gas supply flow rate and an instruction button  21   k  for an abdominal cavity which are included in the preset operation part  41 . 
   In the preset display  21 E, there are provided a display  21   l  for luminal cavity flow rate which is included in the display  42 , and an instruction button  21   m  for a luminal cavity and a preset button  21   n  for gas supply flow rate which are included in the preset operation part  41 . 
   The power switch  21   d  switches on and off a power source of the gas supply apparatus  21 . The gas supply start button  21   b  is a button for instructing to start gas supply. The gas supply stop button  21   c  serves as a switch for switching from a gas supplying state to a gas supply stopped state. 
   Each of the preset button  21   i  for internal pressure of an abdominal cavity and the preset button  21   j  for supply gas flow rate has two operational buttons. It is configured such that proper operation of these buttons allows variation in a preset value in a gradually increasing manner or a gradually decreasing manner. 
   The residual gas quantity display  21   a  indicates a residual quantity of carbon dioxide gas in the carbon dioxide gas container  29 . The display  21   e  for internal pressure of an abdominal cavity has two displays, right and left, with the right display indicating a value based on the measurement by the pressure sensor  37 , and with the left display indicating, for example, a preset pressure which has been input through the preset button  21   i  for internal pressure of an abdominal cavity. 
   The flow rate display  21   f  has two displays, right and left, with the right display indicating, for example, a value based on the measurement by the first flow sensor  38 , and with the left display indicating a preset flow rate which has been input through the preset button  21   j  for gas supply flow rate. 
   The total gas supply display  21   g  indicates a total gas quantity which has been obtained through an arithmetic operation by the controller  40  based on the measurement of the first flow sensor  38 . When a value measured by the pressure sensor  37  becomes higher, by a predetermined pressure, than a preset value of an abdominal cavity internal pressure, the pressure warning lamp  2   h  gives warning accordingly by varying the state of the lamp from, for example, an off-state to a flickering state or to a red light emitting state in response to a control signal from the controller  40 . 
   The abdominal cavity instruction button  21   k  serves as an instruction button for selecting a mode for the gas supply apparatus  21  to supply carbon dioxide gas into an abdominal cavity. A gas supply mode for an abdominal cavity is adapted to be selected by operating the button. 
   The luminal cavity flow rate display  21   l  has two displays, right and left, with the right display indicating a value based on the measurement by the flow sensor  39 , and with the left display indicating a preset flow rate which has been input through an operation of the supply gas flow rate preset button  21   n.    
   The luminal cavity instruction button  21   m  serves as an instruction button for selecting a mode for the gas supply apparatus  21  to supply carbon dioxide gas into a luminal cavity. A gas supply mode for a luminal cavity is adapted to be selected by operating the button. 
   The supply gas flow rate preset button  21   n  has two operational buttons for presetting a flow rate of carbon dioxide gas when it is supplied into a luminal cavity by the gas supply apparatus  21 . Proper operation of these buttons allows variation of a preset value in a gradually increasing manner or in a gradually decreasing manner. 
   Note that a pressure warning lamp for a luminal cavity, similar to the pressure warning lamp  2   h  may be provided at the preset display  21 E for a luminal cavity. 
   Further, the present embodiment is configured such that when both of the abdominal cavity instruction button  21   k  and the luminal cavity instruction button  21   m  are operated together, a gas supply mode for an abdominal cavity and a gas supply mode for a luminal cavity may be simultaneously performed. 
   The gas supply apparatus  21  of the present embodiment has two gas supply fittings, i.e. the abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B, with the configuration wherein a abdominal insufflation apparatus and an ECR are integrated as described hereinbefore. Accordingly, in case of providing such two gas supply fittings  21 A and  21 B for an abdominal cavity and a luminal cavity, respectively, it is necessary to prevent erroneous connection so that carbon dioxide gas is supplied to each of the gas supply fittings with a right gas supply pressure. 
   Therefore, the gas supply apparatus  21  of the present embodiment undergoes improvements in the abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B in order to prevent erroneous connection. An example of such a configuration is described with reference to  FIGS. 6A ,  6 B and  6 C. 
   In the gas supply apparatus  21  of the present embodiment, carbon dioxide gas having a pressure suitable for an abdominal cavity should be supplied to the abdominal cavity supply fitting  21 A under the control of the controller  40  over the first electropneumatic proportional valve  33 , and carbon dioxide having a pressure suitable for a luminal cavity should be supplied to the luminal cavity supply fitting  21 B under the control of the controller  40  over the second electropneumatic proportional valve  34 . 
   As shown in  FIG. 6A , the gas supply apparatus  21  of the present embodiment is provided with the abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B having pieces of means for preventing erroneous connection, respectively, which prevent erroneous connection (i.e. inversely connected state) between the abdominal cavity tube  10  and the luminal cavity tube  22 . 
   The abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B are adapted, for example, to differentiate the outer diameters of the fittings from each other as well as to differentiate the number of projections from each other provided on the outer peripheries of the fittings so as to enable identification of one fitting from the other, thereby preventing erroneous connection. 
   A connector (hereinafter referred to an abdominal cavity connector)  43  for the abdominal cavity tube  10 , which is to be connected to the abdominal cavity supply fitting  21 A, and a connector (hereinafter referred to a luminal cavity connector)  44  for the luminal cavity tube  22 , which is to be connected to the luminal cavity supply fitting  21 B, are configured, respectively, although not shown, to have shapes matched to those of the gas supply fittings. 
   As shown in  FIG. 6B , the abdominal cavity supply fitting  21 A, for example, has a larger outer diameter than the luminal cavity supply fitting  21 B, and is formed to have a single projection  45  at a predetermined position on its outer periphery. Further, the abdominal cavity connector  43  is formed to have an inner diameter, not shown, that matches the outer diameter of the abdominal cavity supply fitting  21 A, with a notch (not shown) being provide in its inner peripheral surface to fit with the projection  45 . In this way, the abdominal cavity connector  43  is adapted to fit into and connected to the abdominal cavity supply fitting  21 A. 
   As shown in  FIG. 6C , the luminal cavity supply fitting  21 B, for example, has a smaller outer diameter than the abdominal cavity supply fitting  21 A, and is formed to have two projections  45  at predetermined positions on its outer periphery. Further, the abdominal cavity connector  44  is formed to have an inner diameter, not shown, that matches the outer diameter of the luminal cavity supply fitting  21 B, with two notches (not shown) being provide in its inner peripheral surface to fit with the two projections  45 , respectively. In this way, the luminal cavity connector  44  is adapted to fit into and connected to the luminal cavity supply fitting  21 B. 
   It should be noted that, in the present embodiment, the abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B are so configured to have varied diameter, number of projections or the like for distinction from each other, however, there is no intention of limiting to these variations. For example, as to outer diameters, those of the pair of the supply fitting  21 B and the connector  44  for luminal cavity may be configured to be larger than those of the pair of the supply fitting  21 A and the connector  43  for abdominal cavity. In addition, the number of projections  45  formed in the outer peripheral surfaces of the abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B, i.e. the number of recesses RS formed in the inner peripheral surfaces of the abdominal cavity connector  43  and the luminal cavity connector  44 , respectively, may not be limited to the number shown in  FIGS. 6B and 6C , and thus, for example, three or more projections and recesses may be provided to the luminal cavity supply fitting  21 B and the luminal cavity connector  44 , respectively. 
   Further, only the outer diameters of the fittings  21 A and  21 B, i.e. only the inner diameters of the connectors  44  and  45  may be differentiated from each other between the uses for an abdominal cavity and a luminal cavity, without forming projections or recesses. Alternatively, Sizes and shapes of the fittings and the connectors may be configured to have completely the same between the uses for an abdominal cavity and a luminal cavity, but to have different numbers or shapes of the projections and recesses for distinction from each other. 
   Furthermore, the fittings and the connectors may be configured to have colored members or the like at the outer peripheries thereof to enable identification from each other. 
   The effects of the gas supply apparatus  21  of the present embodiment are described below. 
   In a laparoscopic surgery, an operator is to connect both of the abdominal cavity tube  10  and the luminal cavity tube  22  to the gas supply apparatus  21  in order to give treatment by internally and externally specifying a site to be treated with the insertion of the endoscope  12  into a luminal cavity, such as a large intestine. 
   On this occasion, as the abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B, as shown in  FIG. 6A , are configured such that the respective diameters are different from each other and that the number of projections provided on the respective peripheries are different from each other, the operator can make a distinction between the abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B only through visual observation. 
   In addition, as the abdominal cavity connector  43  and the luminal cavity connector  44  are configured to have shapes that match those of the two supply fittings  21 A and  21 B, respectively, when the operator erroneously attempt to connect the luminal cavity connector  44  to the abdominal cavity supply fitting  21 A, no fitting or connection is obtained. Of course, contrarily, however an operator may attempt to connect the luminal cavity supply fitting  21 B to the abdominal cavity connector  43 , no fitting or connection is obtained. Thus, erroneous connection can be prevented. 
   In the gas supply apparatus  21  of the present embodiment, when an operator operates the abdominal cavity instruction button  21   k , the luminal cavity instruction button  21   m  and the gas supply start button  21   b , carbon dioxide gas having a pressure suitable for an abdominal cavity is supplied, as described above, to the abdominal cavity supply fitting  21 A under the control of the controller  40  over the first electropneumatic proportional valve  33 , and similarly, carbon dioxide gas having a pressure suitable for a luminal cavity is supplied to the luminal cavity supply fitting  21 B under the control of the controller  40  over the second electropneumatic proportional valve  34 . In short, gas supply with right pressure is effected to the abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B. 
   Thus, according to the present embodiment, effective utilization of a space can be achieved by allowing the gas supply apparatus  21  to have a function of a conventional abdominal insufflation apparatus and a function of an ECR. 
   In addition, as the abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B are provided in juxtaposition in the integrated front panel FP of the gas supply apparatus  21 , connecting operation can be performed in shorter time and in a smoother manner than a conventional system wherein connectors have to be connected to gas supply fittings that are provided in separate devices, respectively, and thus less erroneous connections come to occur. This correct tube connection for inflating both an abdominal cavity and a luminal cavity by simultaneously supplying carbon dioxide gas therein may ensure sufficient visual fields for the endoscopes  5  and  12 , and treatment tools (not shown), respectively. 
   Further, in the gas supply apparatus  21  of the present embodiment, means for preventing erroneous connection in connecting the abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B to the abdominal cavity connector  43  and the luminal cavity connector  44 , respectively, are positively established. Therefore, erroneous connection of the connectors can be prevented, and hence carbon dioxide gas may be supplied at right gas supply pressures through these two abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B, respectively. 
   Second Embodiment 
   An endoscopic system in which a second embodiment of a gas supply apparatus of the present invention is implemented, is described with reference to  FIGS. 7 to 9 . Note that in this embodiment, the same or like functional effects are referred to by the same reference numbers to omit or simplify the description. The manner of omission and simplification is applied to a third and the subsequent embodiments. 
   The gas supply apparatus  21  of the present embodiment provides the abdominal cavity supply fitting  21 A and the luminal cavity supply fitting  21 B both having entirely the same size, but is different from the first embodiment in that a connecting state is electrically detected and that a gas supply to the two supply fittings  21 A and  21 B is controlled depending on the results of the detection. 
   As shown in  FIG. 7A , the front panel FP of the gas supply apparatus  21  of the present embodiment is provided with an abdominal cavity supply fitting  46 A and a luminal cavity supply fitting  46 B of approximately the same shape (the same diameter), each having three electrical contacts  46   b  which are formed on a respective outer peripheral surface. 
   Each of these electrical contacts  46   b  consists of a pair of conductive electrical pieces. For the present embodiment, as shown in  FIGS. 7C and 7E , three electrical contacts  46   b  are formed, by way of example, at each of the abdominal cavity supply fitting  46 A and the luminal cavity supply fitting  46 B. In addition, a positioning groove  46   a  is provided at a portion on an outer peripheral surface of each of the abdominal cavity fitting  46 A and the luminal cavity supply fitting  46 B. 
   An abdominal cavity connector  43 A and a luminal cavity connector  44 A are configured to have a shape that fits into the two supply fittings  46 A and  46 B, respectively. The abdominal cavity connector  43 A and the luminal cavity connector  44 A are configured to have electrical contacts  43   b , on inner peripheries thereof, which are to be electrically in contact with the electrical contacts  46   b , respectively. The electrical contacts  43   b  are comprised, for example, of a conductive material. For the present embodiment, as shown in  FIG. 7B , two electrical contacts  43   b  are formed, by way of example, at the abdominal cavity connector  43 A. In addition, as shown in  FIG. 7D , three electrical contacts  43   b  are formed, by way of example, at the luminal cavity connector  44 A. Further, the abdominal cavity connector  43 A and the luminal cavity connector  44 A are configured to have positioning projections  43   a  and  44   a , at a predetermined position in inner peripheral surfaces thereof, respectively, to fit into the positioning grooves  46   a , respectively, and to be in position. 
   Specifically, as shown in  FIG. 7B , two electrical contacts  43   b  are disposed at predetermined positions at a lower inner peripheral surface of the abdominal cavity connector  43 A. The abdominal cavity supply fitting  46 A, as shown in  FIG. 7C , to which the abdominal cavity connector  43 A is fitted is provided with three electrical contacts  46   b.    
   It is configured such that, in fitting the abdominal cavity connector  43 A into the abdominal cavity supply fitting  46 A for connection, the positioning projection  43   a  is engaged with the positioning groove  46   a  to ensure electrical contact between the two electrical contacts  43   b  and the two electrical contacts  46   b , respectively. 
   Further, the electrical contacts  46   b  of the abdominal cavity supply fitting  46 A and the electrical contacts  43   b  of the abdominal cavity connector  43 A form a first detector  21 A 1  as a sensor (see  FIG. 8 ). 
   The respective electrical contacts  46   b  of the fitting  46 A are connected to the controller  40  and are applied current from the controller  40  at the time connection is judged. Therefore, when the contacts  46   b  and  43   b  are, respectively, in contact with each other, the controller  40  may obtain an electrical signal indicative of normality of connection in response to such a current application. Specifically, for the present embodiment, the controller  40  judges as to whether or not the connection is in normality wherein electrical signals indicative of connection are obtained from the two of the three electrical contacts  46   b , which are in predetermined positions, provided at the abdominal cavity supply fitting  46 A. This may allow the first detector  21 A 1  to function as a sensor for detecting a state of connection between the abdominal cavity supply fitting  46 A and the abdominal cavity connector  43 A. Briefly, the controller  40  can obtain information as to whether or not the fitting and the connector are appropriately in electrical connection with each other. 
   Contrarily, where connection is out of the above described normality (i.e. when signals indicative of contact is obtained from one or three of the three electrical contacts  46   b  of the abdominal cavity supply fitting  46 A, or when no signal indicative of contact is obtained from any of the contacts  46   b ), the controller  40  can obtain electrical signals indicative of abnormality of connection (erroneous connection). 
   In short, as shown in  FIG. 8 , the first detector  21 A 1  may function as a sensor for detecting a state of connection between the connector and the fitting, and may give information to the controller  40  as to whether or not the two of the electrical contacts  43   b  and two electrical contacts  46   b , respectively, are appropriately in electrical contact with each other. 
   As shown in  FIG. 7D , three electrical contacts  43   b  are disposed at predetermined positions at a lower inner peripheral surface of the luminal cavity connector  44 A. 
   The luminal cavity supply fitting  46 B to fit into the luminal cavity connector  44 A is provided, as shown in  FIG. 7E , with three electrical contacts  46   b  at predetermined positions on an outer peripheral surface so as to be electrically connected to the three electrical contacts  43   b , respectively, of the luminal cavity connector  44 A. 
   It is configured such that, in fitting the luminal cavity connector  44 A to the luminal cavity supply fitting  46 B for connection, the positioning projection  44   a  is engaged with the positioning groove  46   a  to ensure electrical connection between the three electrical contacts  43   b  and the three electrical contacts  46   b , respectively, as described hereinbefore. 
   The electrical contacts  46   b  of the luminal cavity supply fitting  46 B and the electrical contacts  43   b  of the luminal cavity connector  44 A form a second detector  21 A 2  as a sensor (see  FIG. 8 ). The respective electrical contacts  46   b  of the fitting  46 B are connected to the controller  40  and are applied current at the time connection is judged. 
   Therefore, when both of the contacts  46   b  and  43   b  are, respectively, in contact with each other, the controller  40  can obtain an electrical signal indicative of normality of connection in response to such a current application. Specifically, for the present embodiment, the controller  40  judges as to whether or not the connection is in normality wherein electrical signals indicative of connection are obtained from all of the three of the three electrical contacts  46   b  provided at the luminal cavity supply fitting  46 B. This may allow the second detector  21 A 2  to function as a sensor for detecting a state of connection between the luminal cavity supply fitting  46 B and the luminal cavity connector  44 A. Briefly, the controller  40  can obtain information as to whether or not the fitting and the connector are in appropriately in electrical connection with each other. 
   Contrarily, when only portions of both of the contacts  46   b  and  43   b , respectively, are apart from each other, the controller  40  can obtain electrical signals indicative of abnormality of connection (erroneous connection). 
   In short, as shown in  FIG. 8 , the second detector  21 A 2  may function as a sensor for detecting a state of connection between the connector and the fitting, and may give information to the controller  40  as to whether or not the three of the electrical contacts  43   b  and  46   b , respectively, are appropriately electrically connected with each other. 
   Other portions of the configuration are the same as or equivalent to those of the first embodiment. 
   Next, effects of the gas supply apparatus  21  of the present embodiment are described. 
   An operator is supposed to fit the abdominal cavity connector  43 A into the abdominal cavity supply fitting  46 A for connection. In this instance, the two electrical contacts  43   b  are reliably connected to the two electrical contacts  46   b , respectively, by allowing the positioning projection  43   a  to engage with the positioning groove  46   a.    
   Also, an operator is supposed to fit the luminal cavity connector  44 A into the luminal cavity supply fitting  46 B for connection. In this instance, the three electrical contacts  43   b  are reliably connected to the three electrical contacts  46   b , respectively, by allowing the positioning projection  44   a  to engage with the positioning groove  46   a.    
   The controller  40  applies current to the first detector  21 A 1  and the second detector  21 A 2  to read out the results of the current application (step S 21  of  FIG. 9 ). As a result of this current application, when the connector  43 A ( 44 A) is correctly connected to the fitting  46 A ( 46 B), a signal having a “0” potential, for example, may be obtained as the electrical contacts  43   b  and  46   b  are brought into electrical conduction with each other. In contrast, when connection is in error, a signal of potential “1”, for example, may be obtained as the electrical contacts  43   b  and  46   b  are partially not in conduction with each other. 
   Then, the controller  40  makes a judgment on whether or not the abdominal cavity connector  43 A is appropriately connected to the abdominal cavity supply fitting  46 A (step S 22 ). Further, a judgment is also made as to whether or not the luminal cavity connector  44 A is appropriately connected to the luminal cavity supply fitting  46 B (step S 23 ). It should be noted that the term “appropriately” in these judgment does not include a case where a state of connection is correct, i.e. not inverted, but “inappropriate (incomplete)”, such as a case where insertion is insufficient. 
   When both of the judgments at the steps S 22  and S 23  are to proceed to YES, i.e. when both of the connectors  43 A and  44 A are judged to be appropriately connected to both of the fittings  46 A and  46 B, respectively, the controller  40  permits the first electropneumatic proportional valve  33  and the second electropneumatic proportional valve  34  to effect pressure control (step S 24 ). Thus, the first electropneumatic proportional valve  33  effects valve control so that its discharge pressure will be a pressure suitable for an abdominal cavity. Also, the second electropneumatic proportional valve  34  effects valve control so that its discharge pressure will be a pressure suitable for a luminal cavity. 
   When an operator has erroneously fit the luminal cavity connector  44 A to the abdominal cavity supply fitting  46 A, as the three electrical contacts  46   b  should then all be in a contacted state, the controller  40  may obtains the results of detection as not having been electrically connected from the first detector  21 A 1  (NO at step S 22 ). Thus, the controller  40 , judging that erroneous connection has occurred, controls the first electropneumatic proportional valve  33  and the first electromagnetic valve  35  so as not to effect a gas supply output, and at the same time allows such a gas-supply-stop indication on the front panel FP, such as by flickering a lamp thereon, not shown, for example (step S 25 ). 
   Further, when an operator has erroneously fit the abdominal cavity connector  43 A to the luminal cavity supply fitting  46 B, as no complete electrical contact is attained with the three electrical contacts  43   b , the controller  40  may also obtain the results of detection as not having been electrically connected from the second detector  21 A 1  (No at step S 23 ). Thus, the controller  40  makes a judgment of erroneous connection as having been made, and controls the second electropneumatic proportional valve  34  and the second electromagnetic valve  36  so as not to effect a gas supply output. 
   Thus, according to the present embodiment, similar effects as in the first embodiment can be obtained. Specifically, when the abdominal cavity tube  10  and/or the luminal cavity tube  22  are erroneously connected to the supply fitting  46 B and/or  46 A, the fact of erroneous connection is automatically and reliably detected to automatically stop a supply of carbon dioxide gas at an inappropriate pressure to the supply fitting  46 A and/or  46 B. 
   Therefore, an operator is obliged to reconnect the tube  10  ( 22 ) to the right fitting  46 A ( 46 B), and when such a reconnection is suitably done, an allowance is made to supply carbon dioxide gas to the supply fitting  46 A and/or  46 B at an appropriate pressure. 
   In this way, according to the present embodiment, a configuration, in which the abdominal cavity supply fitting  46 A and the luminal cavity supply fitting  46 B have a similar shape, cannot result in erroneous connection but enables a supply of carbon dioxide gas at a right pressure to the respective two supply fittings  46 A and  46 B. The common diameter and the shape between the fittings  46 A and  46 B are advantageous from a viewpoint of manufacturing cost. 
   Third Embodiment 
   An endoscopic system in which a third embodiment of the gas supply apparatus of the present invention is implemented is described with reference to  FIGS. 10A to 10D  and  11 . 
   The present embodiment is an improvement of the gas supply apparatus  21  of the second embodiment, which is different from the second embodiment in that the present embodiment is configured such that distinction between an abdominal and luminal cavity connectors is made not based on contact/noncontact between the electrical contacts, but based on the results of detection of an internal resistance at the electrical contacts. 
   As shown in  FIGS. 10A and 10D , the gas supply apparatus  21  of the present embodiment is provided with an abdominal cavity supply fitting  47 A and a luminal cavity supply fitting  47 B having the same shape (the same diameter), which is approximately the same as the second embodiment. Each of the abdominal cavity supply fitting  47 A and the luminal cavity supply fitting  47 B has two electrical contacts  47   b  on an outer peripheral surface thereof. 
   An abdominal cavity connector  43 B and a luminal cavity connector  44 B are configured so as to have shapes that fit into the two supply fittings  46 A and  46 B, respectively, which is approximately the same as the second embodiment. The abdominal cavity connector  43 B and the luminal cavity connector  44 B are configured so as to have two electrical contacts  43   b  and two electrical contacts  46   b , respectively, at positions on respective inner peripheral surfaces thereof, which match the positions of the electrical contacts  47   b  for electrical connection therebetween. 
   As shown in  FIG. 10B , the abdominal cavity connector  43 B has, at the two electrical contacts  43   b , a resistance which is equivalent to a resistor R 1 . The resistance of the resistor R 1  is an internal resistance of the electrical contacts  43   b.    
   As shown in  FIG. 10C , the luminal cavity connector  44 B has, at the two electrical contacts  46   b , a resistance which is equivalent to a resistor R 2 . The resistance of the resistor R 2  is an internal resistance of the electrical contacts  46   b . In the present embodiment, the resistances of the resistor R 1  and the resistor R 2  are not the same but are predetermined different resistances which are adapted to be recorded on a memory, not shown, in the controller  40 . 
   In the present embodiment, it is configured that, when the abdominal cavity connector  43 B is fit into the abdominal cavity supply fitting  47 A for connection, a positioning projection  43   a  is brought into engagement with a positioning groove  47   a , by which the two electrical contacts  43   b  are reliably electrically connected to the two electrical contacts  47   b , respectively. 
   Also, it is configured that, when the luminal cavity connector  44 B is fit into the luminal cavity supply fitting  47 B for connection, a positioning projection  44   a  is brought into engagement with the positioning groove  47   a , in the like manner as described above, by which the two electrical contacts  46   b  are reliably electrically connected to the two electrical contacts  47   b , respectively. 
   Further, the electrical contacts  47   b  of the abdominal cavity supply fitting  47 A and the electrical contacts  47   b  of the luminal cavity supply fitting  47 B are configured to be connected to the controller  40 , as in the second embodiment, so as to be charged with electricity from the controller  40  at the time of judging connection. 
   Thus, the two electrical contacts  47   b  of the abdominal cavity supply fitting  47 A and the two electrical contacts  43   b  (resistor R 1 ) of the abdominal cavity connector  43 B constitute a first detector  21 A 1  as a sensor. Also, the two electrical contacts  47   b  of the luminal cavity supply fitting  47 B and the two electrical contacts  46   b  (resistor R 2 ) of the luminal cavity connector  44 B constitute a second detector  21 A 2  as a sensor (see  FIG. 8  as described hereinbefore). 
   Other portions of the configuration are similar to those of the second embodiment. 
   In the present embodiment, a description has been given of a configuration in which are provided two electrical contacts  43   b  and two electrical contacts  47   b  for an abdominal cavity side, and two electrical contacts  46   b  and two electrical contacts  47   b  for a luminal cavity side. However, without limitation to this, other configuration may be provided in which at least one electrical contact is provided each at an abdominal cavity side and a luminal cavity side, and resistors R 1  and R 2  of different resistances are provided at the connector side electrical contacts, respectively. 
   Next, effects of the gas supply apparatus  21  of the present embodiment are described with reference to  FIG. 11 . 
   In a laparoscopic surgery, an operator is to connect the abdominal cavity tube  10  and the luminal cavity tube  22  to the gas supply apparatus  21  in order to give treatment by inserting the endoscope  12  into a luminal cavity, such as a large intestine for internal and external specification of a site to be treated. 
   At this time, assuming that the gas supply apparatus  21  is switched on, the controller  40  starts a program shown in  FIG. 11 . 
   The controller  40  charges electricity to the first detector  21 A 1  and the second detector  21 B 1  through a process at step S 1 , by which each of the resistances of the resistors R 1  and R 2  of the connected connectors (the abdominal cavity connector  43 B and the luminal cavity connector  44 B) is detected (measured). 
   Thereafter, the controller  40  makes a judgment, through a judgment process at step S 2 , as to whether or not the resistance detected by the first detector  21 A 1  is the same as a resistance of the resistor R 1  of the abdominal cavity connector  43 B. 
   In case the detected resistance is judged to be the same as the resistance of the resistor R 1  of the abdominal cavity connector  43 B, the controller  40  allows processes to proceed to step S 3 . Contrarily, in case a judgment is made as being different, erroneous connection is regarded to have occurred at step S 5 , which is then informed to an operator by lighting up an erroneous connection indicator, not shown, of the display  42 . At the same time, the first electropneumatic proportional valve  33  and the first electromagnetic valve  35  are controlled so as to stop supply of carbon dioxide gas, and then processes are allowed to return to step S 1 . 
   In the judgment process at step S 3 , the controller  40  judges on whether or not the resistance detected by the second detector  21 B 1  is the same as the resistance of the resistor R 2  of the luminal cavity connector  44 B. 
   In case the detected resistance is judged to be the same as the resistance of the resistor R 2  of the abdominal cavity connector  44 B, the controller  40  allows processes to proceed to step S 4 . Contrarily, in case a judgment is made as being different, processes are allowed to proceed to step S 5  to carry out processing of indication in this regard and of stopping gas supply output, as described above, and then processes are allowed to return to step S 1 . 
   The controller  40  then controls, in the process at step S 4 , the first electropneumatic proportional valve  33  so that carbon dioxide gas having a pressure suitable for an abdominal cavity is supplied to the abdominal cavity supply fitting  47 A, and at the same time, controls the second electropneumatic proportional valve  34  so that carbon dioxide gas having a pressure suitable for a luminal cavity is supplied to the luminal cavity supply fitting  47 B. Then, the controller  40  allows processes to return to step S 1  being ready for next connection of connectors. 
   Thus, according to the present embodiment, when the abdominal cavity supply fitting  47 A and the luminal cavity supply fitting  47 B are configured to have the same shape, erroneous connection is ultimately prevented as in the second embodiment, and carbon dioxide gas is allowed to be supplied to the respective two supply fittings  47 A and  47 B with right pressures. 
   Fourth Embodiment 
   An endoscopic system in which a fourth embodiment of the gas supply apparatus of the present invention is implemented is described with reference to  FIG. 12 . It should be noted that in  FIG. 12 , like processing contents as the ones shown in  FIG. 11  of the third embodiment are referenced by the same step number. 
   In the present embodiment, the gas supply apparatus  21  is approximately the same as the one in the third embodiment except that the present embodiment is configured such that the controller  40  performs automatic control by detecting internal resistances at electrical contacts, judging on connections of luminal cavity and abdominal cavity connectors based on the results of the detection, and supplying gas at optimal predetermined pressures depending on the type of connected connectors based on the results of the judgment. 
   Other portions of the configuration of the gas supply apparatus  21  are similar to those of the second embodiment. 
   Effects of the gas supply apparatus  21  of the present embodiment are described with reference to  FIG. 12 . 
   In a laparoscopic surgery, an operator is to connect the abdominal cavity tube  10  and the luminal cavity tube  22  to the gas supply apparatus  21  in order to give treatment by inserting the endoscope  12  to a luminal cavity, such as a large intestine for internal and external specification of a site to be treated. 
   At this time, assuming that the gas supply apparatus  21  is switched on, the controller  40  starts the program shown in  FIG. 12 . 
   Then, in the process at step S 1 , the controller  40  detects (measures), via the first detector  21 A 1  and the second detector  21 B 1 , respective resistances of the resistors R 1  and R 2  of the connectors (the abdominal cavity connector  43 B and the luminal cavity connector  44 B) connected to the fittings  47 A and  47 B, respectively. 
   Thereafter, the controller  40  makes a judgment, in the process at step S 2 , on whether or not the resistance detected by the first detector  21 A 1  is the same as the resistance of the resistor R 1  of the abdominal cavity connector  43 B. 
   In case the detected resistance is judged to be the same as the resistance of the resistor R 1  of the abdominal cavity connector  43 B, the controller  40  allows processes to proceed to step S 10 . Contrarily, in case a judgment is made as being different, processes are allowed to proceed to step S 11 . 
   At step S 10 , the controller  40  sets a pressure value for abdominal cavity to be used for supplying carbon dioxide gas of a pressure suitable for an abdominal cavity to the abdominal cavity supply fitting  47 A, and at the same time, controls the first electropneumatic proportional valve  33  based on the set pressure value for abdominal cavity, and then processes are allowed to proceed to step S 3 . 
   In a judgment process at step S 11 , the controller  40  judges as to whether or not the resistance detected by the first detector  21 A 1  is the same as the resistance of the resistor R 2  of the luminal cavity connector  44 B. In case the detected resistance is judged to be the same as the resistance of the resistor R 2  of the luminal cavity connector  44 B, the controller  40  judges the luminal cavity connector  44 B as having been connected to the abdominal cavity supply fitting  47 A. Then, in a process at step S 12 , a pressure value for a luminal cavity is set to supply carbon dioxide gas of a pressure suitable for the luminal cavity from the abdominal cavity supply fitting  47 A, and based on the set pressure for a luminal cavity, the first electropneumatic proportional valve  33  is controlled. After that, processes are allowed to proceed to step S 3 . If the resistance is judged not to be the same in a judgment process at step S 11 , processes are, as well, allowed to return to step S 3 . 
   In the judgment process at step S 3 , the controller  40  makes a judgment as to whether or not the resistance detected by the second detector  21 B 1  is the same as the resistance of the resistor R 2  of the luminal cavity connector  44 B. 
   When the detected resistance is judged to be the same as the resistance of the resistor R 2  of the luminal cavity connector  44 B, the controller  40  allows processes to proceed to step S 13 , and when the resistance is judged as not being the same, processes are allowed to proceed to step S 14 . 
   At step S 13 , the controller  40  sets a pressure value for a luminal cavity to supply carbon dioxide gas of a pressure suitable for a luminal cavity to the luminal cavity supply fitting  47 B, and at the same time, controls the second electropneumatic proportional valve  34  based on the set pressure value for a luminal cavity, and then processes are allowed to return to steps S 1 . 
   In a judgment process at step S 14 , the controller  40  judges on whether or not the resistance detected by the second detector  21 B  1  is the same as the resistance of the resistor R 1  of the abdominal cavity connector  43 B. In case the detected resistance is judged to be the same as the resistance of the resistor R 1  of the abdominal cavity connector  43 B, the controller  40  judges the abdominal cavity connector  43 B as having been connected to the luminal cavity supply fitting  47 B. Then, in a process at step S 15 , the controller  40  sets a pressure value for an abdominal cavity to supply carbon dioxide gas of a pressure suitable for an abdominal cavity from the luminal cavity supply fitting  47 B, and controls the second electropneumatic proportional valve  34  based on the set pressure value for an abdominal cavity. Thereafter, processes are allowed to return to step S 1 . Meanwhile, in case a judgment is made as not being the same, processes are, as well, allowed to return to step S 1 . 
   Thus, even when a wrong connector has been erroneously connected to the abdominal cavity supply fitting  47 A and the luminal cavity supply fitting  47 B, gas supply can be performed with a right pressure via the abdominal cavity supply fitting  47 A and the luminal cavity supply fitting  47 B, depending on the abdominal cavity connector  43 B or the luminal cavity connector  44 B that has been connected. 
   Thus, according to the present embodiment, irrespective of the occurrences of erroneous connection, the abdominal cavity connector  43 B and the luminal cavity connector  44 B are automatically identified, and based on the results of the identification, gas supply can be carried out with a right pressure. Such an automatic control enables automatic gas supply, even when an abdominal cavity side gas supply conduit or a luminal cavity side gas supply conduit breaks down, at an optimum pressure for an abdominal cavity or a luminal cavity through a supply fitting which is in order, thereby allowing an operation to proceed without interruption. 
   The gas supply apparatus of each of the embodiments described above is configured such that an abdominal cavity supply fitting and a luminal cavity supply fitting are integrally provided and that carbon dioxide gas can be supplied at a right pressure through respective supply fittings, and accordingly that the space of an operating room can be effectively utilized. The gas supply apparatus of each of the embodiments is especially effective in a laparoscopic surgery wherein treatment is given by inserting an endoscope into a luminal cavity for internal and external specification of a site to be treated. 
   The present invention is not limited to the first to fourth embodiments described above, but may be embodied in many other ways with various modulations without departing from the scope of the invention. Additionally, the embodiments described above include inventions at various stages, and thus suitable combinations of the disclosed plurality of components may extract various inventions.