Abstract:
An electronic anesthesia delivery apparatus for mixing a carrier gas and first and second anesthetic agents comprises a chassis having an electronic vaporizer, the vaporizer having a first anesthetic chamber and a second anesthetic chamber retaining the first anesthetic agent and the second anesthetic agent, a carrier gas input port in flow communication with the first anesthetic chamber and the second anesthetic chamber, a precision orifice and an electronic control valve corresponding to each of the chambers being downstream of the gas input port, each of the chambers having a conduit in flow communication with the carrier gas input port, each of the conduits extending into each of the chambers below an upper level of anesthetic agent, wherein the carrier gas passes through a porous diffuser near an end of the conduit and bubbles through the anesthetic agent, the chamber further comprising an anesthetic gas outlet port, an electronic touchscreen display for controlling carrier gas flow rate to the first anesthetic chamber and the second anesthetic chamber, the electronic touchscreen display further allowing control of concentrations of the anesthetic agent in an anesthesia to a patient by intermittently opening and closing of the electronic control valve, a circuit board having an input/output portion, the circuit board in electronic communication with the electronic touchscreen display, the input/output portion receiving temperature of the anesthetic agent, the electronic anesthesia delivery apparatus allowing use of a first anesthetic agent while a second anesthetic agent is one of either replaced or substituted in the second chamber.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application is a Continuation-In-Part application claiming priority to and benefit from, currently pending, U.S. patent application Ser. No. 11/031,661, filed on Jan. 7, 2005. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    None. 
       REFERENCE TO SEQUENTIAL LISTINGS, ETC. 
       [0003]    None. 
       BACKGROUND 
       [0004]    1. Field of the Invention 
         [0005]    The present invention provides an anesthesia delivery apparatus. More specifically, the present invention comprises an electronic anesthesia delivery apparatus for controlling delivery of at least two anesthetic agents from at least two respective diffusers to a patient. 
         [0006]    2. Description of the Related Art 
         [0007]    Standard anesthesia delivery machines utilize a plurality of mechanical components to deliver a measured amount of anesthesia to a patient, for example, an animal. Many of these standard devices include an oxygen flow meter, a pressure gauge, and a vaporizer. Such vaporizers typically include a canister housing an anesthetic agent and a wicking material. As the wicking material absorbs the anesthetic agent, oxygen flows by the wicking material and vaporizes the anesthetic agent molecules for delivery to the patient. In order to vary the delivery percentage of drug to the user, an oxygen control valve is opened or closed in order to vary the amount of oxygen flowing past the wicking material, thus varying the percentage of drug delivered to the patient. A mechanical thermostat regulates the division of oxygen flow within the vaporizer in order to compensate for changes in temperature of the anesthetic agent due to the vaporizing process, or due to change in room temperature 
         [0008]    One problem associated with the above mentioned traditional vaporizers is that being mechanical, the vaporizer loses accuracy due to wear of the internal mechanical thermostats and loss of efficiency of the wicking material. Therefore the vaporizer must be periodically removed and sent to a repair facility for overall. Another problem is the specifications for vaporizers on the market today. Most have accuracy of +/−15% of the percentage flow rate indicated and others have accuracy specification of +/−20% of the indicated percentage flow rate of anesthesia. Yet another problem is their up-front expense and the inability to be easily converted to new drug types. In order to convert to a new drug type, the wicking material must be replaced requiring removal of the canister from the machine. Such design is not cost effective. It would be preferable to design a device wherein anesthetic agent may be replaced rather than requiring replacement of the entire canister and the wicking material. 
         [0009]    Another weakness of the traditional vaporizers is their percentage of anesthesia output with respect to flow over a time period. Initially the output percentage is low at start up flows and increases to the output dial setting then holds steady at about +/−15 to 20% (percent) of a dial setting through oxygen flows of up to about 7 to 10 liters of flow. After that point the output percentage decreases due to the higher flowrates of oxygen flowing through the vaporizer. 
         [0010]    Another problem is that physicians must manually operate mechanical valves and dials on anesthesia machines. Typically, these valves must be operated at different locations of the anesthesia machine. This is difficult and requires the physician or assistant to look to different locations of the delivery apparatus to make adjustments. Further, the physician or assistant must try to compensate for temperature and flows based on information provided by the gauges. It would be preferable to design a device which may be controlled by a single interface and which compensates for operating conditions electronically. 
         [0011]    Given the foregoing, it will be appreciated that an apparatus is required which overcomes the aforementioned difficulties and deficiencies. 
       SUMMARY OF THE INVENTION 
       [0012]    According to one embodiment, an electronic anesthesia delivery apparatus, comprises a chassis having at least one anesthetic vaporizer, an oxygen input port in flow communication with the at least one anesthetic vaporizer, and a touchscreen display mounted to the chassis comprising an electronic touchscreen display for controlling an oxygen flow rate to the at least one anesthetic vaporizer and concentration of anesthetic gas delivered to a patient. 
         [0013]    A breathing circuit is defined between a patient and the anesthesia delivery apparatus. The electronic anesthesia delivery apparatus further comprises an oxygen source in fluid communication with the oxygen input port of the anesthesia delivery apparatus. Electronically controlled valves selectively control flow of oxygen from the source to the first and second chambers. A first port is in fluid communication with a first chamber and a second port in fluid communication with a second chamber. An absorber is in fluid communication with a breathing circuit, the absorber scrubbing carbon dioxide from the gas directed therein. 
         [0014]    The electronic anesthesia delivery apparatus further comprises an input/output portion having at least one processor in electronic communication with said electronic touchscreen display. The first and second chambers each having a level sensor and a temperature sensor in electronic communication with an input/output portion. The electronically controlled valves are in electronic communication with the input/output portion. 
         [0015]    According to a second exemplary embodiment, an electronic anesthesia delivery apparatus comprises a chassis including a first anesthetic agent chamber and a second anesthetic agent chamber, each of the first and second chambers including an anesthetic agent therein. At least one electronically controlled valve is in fluid communication with each of the first agent chamber and the second agent chamber and an oxygen source. The oxygen source is in fluid communication with each of the at least one electronically controlled valves. A touchscreen graphic display having controls corresponding to each of the at least one electronically controlled valves for controlling flow rate and concentration of anesthesia. 
         [0016]    The electronic anesthesia delivery apparatus includes at least one electronically controlled valve in electrical communication with an input/output portion and the touchscreen graphic display. The touchscreen graphic display is utilized to start and stop said anesthesia delivery apparatus. The touchscreen graphic display indicates a concentration setting for each of the first anesthetic agent and the second anesthetic agent, as well as an oxygen flow rate through the anesthesia delivery apparatus. The touchscreen graphic display further comprises an agent level indicator for each of the first and second chambers and a plurality of controls and gauges for the electronic anesthesia delivery apparatus. The first and second agent chambers are bubbling diffusers. 
         [0017]    According to a third embodiment, an electronic anesthesia delivery apparatus, comprises a chassis comprising first and second anesthetic agent chambers. The first and second agent chambers are in fluid communication with a plurality of electronically controlled valves. A touchscreen graphics display is in electronic communication with the electronically controlled valves. The touchscreen display comprises a plurality of controls for controlling the electronically controlled valves, the touchscreen display further indicating a oxygen flow rate and concentrations of anesthesia. The electronic anesthesia delivery apparatus further comprises an input/output portion in electronic communication with the touchscreen graphic display. The touchscreen graphics display and the electronically controlled valves control concentration and flowrate of at least one anesthesia. The first and second agent chambers comprise bubbling diffusers for mixing oxygen and anesthetic agent. It is also preferable that when a different anesthetic agent is utilized, a chamber which was previously used may be filled with a different anesthetic agent and a processor may be programmed with code containing an algorithm for controlling a concentration. 
         [0018]    An electronic anesthesia delivery apparatus for mixing a carrier gas and first and second anesthetic agents comprises a chassis having an electronic vaporizer, the vaporizer having a first anesthetic chamber and a second anesthetic chamber retaining the first anesthetic agent and the second anesthetic agent, a carrier gas input port in flow communication with the first anesthetic chamber and the second anesthetic chamber, a precision orifice and an electronic control valve corresponding to each of the chambers being downstream of the gas input port, each of the chambers having a conduit in flow communication with the carrier gas input port, each of the conduits extending into each of the chambers below an upper level of anesthetic agent, wherein the carrier gas passes through a porous diffuser near an end of the conduit and bubbles through the anesthetic agent, the chamber further comprising an anesthetic gas outlet port, an electronic touchscreen display for controlling carrier gas flow rate to the first anesthetic chamber and the second anesthetic chamber, the electronic touchscreen display further allowing control of concentrations of the anesthetic agent in an anesthesia to a patient by intermittently opening and closing of the electronic control valve, a circuit board having an input/output portion, the circuit board in electronic communication with the electronic touchscreen display, the input/output portion receiving temperature of the anesthetic agent, the electronic anesthesia delivery apparatus allowing use of a first anesthetic agent while a second anesthetic agent is one of either replaced or substituted in the second chamber. The electronic anesthesia delivery apparatus further comprises a carrier gas line which bypasses the first and second anesthetic chambers. The electronic anesthesia delivery apparatus wherein the carrier gas line is in flow communication with the electronic vaporizer downstream of the first and second chambers. The electronic anesthesia delivery apparatus wherein the apparatus allows mixing of two anesthetic agents to be delivered to a patient. The electronic anesthesia delivery apparatus wherein the delivery of the agents occurs independently. The electronic anesthesia delivery apparatus wherein the delivery of the agents occurs simultaneously. The electronic anesthesia delivery apparatus further comprises a flow sensor in flow communication with the carrier gas input port. The electronic anesthesia delivery apparatus wherein the flow sensor senses pressure differentials. 
         [0019]    An electronic anesthesia delivery apparatus comprises a chassis having an anesthetic vaporizer including first and second anesthetic chambers and a touchscreen graphics display comprising controls for said anesthetic vaporizer, a circuit board including an input/output portion, the touchscreen graphics display in electronic communications with the circuit board, the circuit board controlling rate of vaporization and concentration of a first and second anesthetic agent disposed in the first and second anesthetic chambers, respectively, at least one electronically controlled valve in fluid communication with each of the first and second anesthetic chambers, the electronically controlled valve in electronic communication with the input/output portion of the circuit board, each of the first anesthetic chamber and the second anesthetic chamber in flow communication with a carrier gas input port, each of the first anesthetic chamber and the second anesthetic chamber having an outlet port, the carrier gas input port in fluid communication with an orifice and the electronically controlled valve, at least one inlet tube in flow communication with the carrier gas input port, each of the at least one inlet tube extending into each of the first and second chambers, wherein either of the first and second anesthetic chambers is refillable while the other of the first and second anesthetic chambers is in use. The electronic anesthesia delivery apparatus further comprises a pulse oximetry sensor in electronic communication with the circuit board. The electronic anesthesia delivery apparatus further comprises an electrocardiography heart wave form. The electronic anesthesia delivery apparatus further comprises a remote control for making operating adjustments. The electronic anesthesia delivery apparatus further comprises an input for a flash memory card. The electronic anesthesia delivery apparatus further comprising a USB port. 
         [0020]    An electronic anesthesia delivery apparatus, comprises a chassis having a carrier gas input port, a first anesthetic chamber and a second anesthetic chamber in fluid communication with the carrier gas input port, the first and second anesthetic chambers including an outlet port, a precision orifice and an electronic control valve in fluid communication with the carrier gas input port and the first and second anesthetic chambers, a circuit board including an input/output portion, the electronic control valve in electronic communication with the circuit board, the circuit board controlling the electronic control valve to vary rate of vaporization and concentration of a first anesthetic agent and a second anesthetic agent, a temperature sensor signal in electronic communication with the circuit board, the temperature sensor signal indicating a temperature of the first and second anesthetic agents, a touchscreen graphics display in electronic communication with the circuit board, each anesthetic chamber having a conduit therein and extending to an elevation beneath the anesthetic agent and having at least one diffuser for bubbling carrier gas through the anesthetic agent. The electronic anesthesia delivery apparatus further comprising a carbon dioxide monitor. The electronic anesthesia delivery apparatus further comprising a network connector. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a front perspective view of a chassis and stand of an exemplary electronic anesthesia delivery apparatus of the present invention; 
           [0022]      FIG. 2  is a front perspective view of the electronic anesthesia delivery apparatus of  FIG. 1  with various operating components attached; 
           [0023]      FIG. 3  is a rear perspective view of the electronic anesthesia delivery apparatus of  FIG. 2  with the rear cover removed; 
           [0024]      FIG. 4  is a schematic diagram of the electronic anesthesia delivery apparatus of  FIG. 2 ; 
           [0025]      FIG. 5  is a schematic diagram of the vaporizer utilized with the electronic anesthesia delivery apparatus of  FIG. 2 ; 
           [0026]      FIG. 6  is an electrical block diagram of the electronic anesthesia delivery apparatus of  FIG. 2 ; 
           [0027]      FIG. 7  is a front view of an exemplary touchscreen graphic display utilized with the present invention; and, 
           [0028]      FIG. 8  is a side sectional view of an exemplary anesthetic agent chamber depicting the diffusion process. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    Referring now in detail to the drawings, wherein like numerals indicate like elements throughout the several views, there are shown in  FIGS. 1-8  various aspects of an electronic anesthesia delivery apparatus which provides several advantages over the prior art. First, the novel electronic anesthesia delivery apparatus utilizes a touchscreen graphics display to electronically control the delivery of anesthesia, or oxygen or other carrier gas alone, to a patient. Second, the device comprises a vaporizer which does not require a wicking material in order to vaporize an anesthetic agent and therefore allows easy conversion from one anesthetic agent to another. Third, the anesthesia delivery apparatus provides improved accuracy in controlling anesthesia output over a range of oxygen flows. For purpose of the following description, anesthesia is meant to comprise an anesthetic agent and a carrier gas such as oxygen, air, nitrous oxide or other suitable carrier. For reasons of clarity of the present description, the carrier gas is stated to be oxygen. 
         [0030]    Referring initially to  FIG. 1 , a front perspective view of a chassis for the electronic anesthesia delivery system  10  is depicted. Specifically, the electronic anesthetic delivery apparatus  10  comprises a chassis  12  mounted on a stand  14 . As depicted, the stand  14  may comprise a vertical leg and a plurality of rollers mounted at a bottom portion of the vertical leg making the electronic anesthetic delivery apparatus  10  movable between, for example, operating rooms. Alternatively, the stand  14  may comprise a plurality of feet, without wheels, extending from the vertical leg or the chassis  12  may be mounted on a wall in an operating room. The chassis  12  comprises an upper housing  16  and a lower housing  18 . The upper housing  16  is substantially rectangular in shape and may further comprise a box-shaped rear cover (not shown). On the front of the upper housing  16  is a window  20  centrally located relative to a vertical axis of the upper housing  16 . The window  20  receives a touchscreen graphics display  22  discussed further herein. 
         [0031]    Still referring to  FIG. 1 , extending from the upper housing  16  is at least one anesthetic agent port. The at least one anesthetic agent port is depicted as a first anesthetic agent port  24  and a second anesthetic agent port  26 . The first anesthetic agent port  24  is utilized to fill a corresponding first chamber  25  ( FIG. 3 ) with a first type of anesthetic agent for use during the surgical procedure. The first anesthesia port  24  may be color coded or include a sticker of a color corresponding to a first type of anesthetic agent. The second anesthetic agent port  26  is also utilized to fill a corresponding second chamber  27  ( FIG. 3 ) with a corresponding second anesthetic agent which may also be utilized during a surgical procedure. The second anesthetic port  26  may also be color coded or have a color coded sticker which corresponds to the second anesthetic agent utilized for a surgery and to further inhibit use of the wrong anesthetic agent. Each of the first and second ports  24 , 26  include a cap to open for filling the chambers and to close once the anesthetic chambers  25 , 27  are filled. In addition, or alternatively, the ports may be keyed mechanically to a specific size or shape, so as to only receive anesthetic agent of a particular type. In such a way, a doctor, nurse or technician cannot fill a port of a particular type with an incorrect agent. 
         [0032]    Referring now to  FIGS. 1 and 2 , the lower housing  18  is substantially rectangular in shape but may comprise alternate shapes. The lower housing  18  also comprises a thickness defining an interior volume wherein a plurality of pipes, tubing, fittings or the like are located in order to partially define a breathing circuit. Alternatively, the lower housing  18  may be formed of a solid block of material wherein ducts defining fluid communication paths may be formed. The lower housing also comprises taps for a pop-off valve  30 , an inhalation valve  32  and an exhalation valve  34 , each depicted in  FIG. 2 . The pop-off valve  30  provides a relief or bleed valve bleeding off excess gas and carbon dioxide from the breathing circuit. In fluid communication with the pop-off valve  30  may be a scavenger system (not shown) defined by, for example, either a charcoal filter or a blower and tubing combination. The charcoal filter (not shown) may be utilized to remove anesthetic agent from gas bleeding from the pop-off valve  30  into an interior room of a structure where a surgical procedure is occurring. Alternatively, a blower and tubing combination (not shown) may be connected to the pop-off valve  30 . The upstream side of the blower may be in fluid communication with the pop-off valve to receive bleed gas comprising anesthesia and carbon dioxide. Further, the blower may force the anesthesia and carbon dioxide through an exterior wall of the structure wherein the procedure is occurring to atmosphere where the anesthesia diffuses. 
         [0033]    As previously indicated an inhalation valve  32  and an exhalation valve  34  are also disposed on the lower housing  18 . The inhalation valve  32  may be a check valve which allows flow of anesthesia from the anesthesia delivery apparatus  10  to the patient in only a single direction. The exhalation valve  34  may also be a check valve which allows flow of carbon dioxide and unconsumed anesthesia back to the lower housing  18  for removal of the carbon dioxide, described hereinafter. Also shown on the lower housing  18  is an inhalation port  33  and an exhalation port  35  which connect tubes to the patient. The tubes and ports  33 , 35  provide fluid communication between the patient and the electronic anesthesia delivery apparatus  10 . 
         [0034]    The lower housing  18  further comprises a flush valve  40  which provides a high flow rate of oxygen through the anesthesia delivery apparatus  10  and the components therein in order to clear any residual anesthesia in the system from a previous surgical procedure. Further the flush valve  40  may be used to charge a re-breathing bag  41  which is used to manually provide oxygen to a patient. The flush valve  40  is defined by a poppet valve (not shown) within the lower housing  18  which is normally closed but opens when a button  43  on the lower housing  18  is depressed. The exemplary flush valve  40  provides a flow rate of up to about 50 liters per minute depending on the patient, whereas the normal flow rate of oxygen through the anesthesia delivery apparatus  10  may be up to about 4 liters per minute. 
         [0035]    Referring now to  FIG. 3 , a rear perspective view of the anesthesia delivery apparatus  10  is depicted with the rear cover removed. A circuit board  50  is depicted behind the touchscreen graphics display  22 . The circuit board  50  comprises an input/output portion  87  ( FIG. 6 ) for communication with controlling and measuring components, memory and at least one processor for running algorithms or programs to regulate concentration of anesthesia. For example the processor may be receiving flow rate and temperature information from the chambers  25 , 27  and compensating to maintain constant percentage output of anesthesia, thus providing improved control in an electronic manner rather than requiring manual determinations as in the prior art. One advantage of the present device is that the system is upgradeable for new anesthetic agents by upgrading the processor with algorithms corresponding to vaporization of the new drug. Also located on the rear surface of the upper housing  16  are first and second chambers  25 ,  27  corresponding to the first anesthesia port  24  and second anesthesia port  26 , respectively. A fill pipe  29  provides fluid communication between the first anesthesia port  24  and the first chamber  25 . A second fill pipe (not shown) also extends between the second anesthesia port  26  and the second chamber  27 . The first and second chambers  25 , 27  are sealed pressure vessels substantially cylindrical in shape with a hollow interior defining a storage area for anesthetic agent and vaporization of the anesthetic agent. The chambers  25 , 27  further comprise ports which receive oxygen input from a pressurized source. The ports may be located at the bottoms of the chambers  25 , 27  in order to best diffuse the anesthetic agent therein. During operation the oxygen diffuses through the chambers  25 , 27  vaporizing the anesthetic agent and forming a vaporized anesthetic agent which is combined with an oxygen flow to define an anesthesia of a preselected concentration. According to the present invention the concentrations may be adjusted electronically with the touchscreen graphics display  22 . Moreover, the circuit board  50  may comprise on-board memory which stores algorithms corresponding to various anesthetic agents. If a new agent is used, a corresponding algorithm should be programmed for accurate vaporization of the new anesthetic agent. 
         [0036]    Also depicted in  FIGS. 1-3 , is an absorber  38 . The absorber  38  is in fluid communication with the exhaled gas of the patient which contains both carbon dioxide and unconsumed anesthesia. The carbon dioxide is absorbed by a plurality of pellets  39  contained within the absorber canister  38 . The pellets  39  may be formed of sodalime material, which is commercially known as Sodasorb and comprises hydrated lime and sodium hydroxide. After the carbon dioxide is removed or scrubbed, the unconsumed anesthesia is directed to the inhalation breathing circuit for delivery to the patient. 
         [0037]    Referring now to  FIG. 4 , a schematic diagram of the anesthesia delivery apparatus  10  is depicted which generally indicates the flow paths of the electronic anesthesia delivery apparatus  10 . The schematic diagram depicts an oxygen source  52  in fluid communication with a flow sensor  56  and an electronic vaporizer  54 . The flow sensor  56  detects flow of oxygen to the apparatus  10  by comprising a thermistor which detects temperature changes. For example, when pressurized oxygen flows over the thermistor, the thermistor senses a temperature drop due to the cooler temperature of the pressurized oxygen. However, when the flow stops, the thermistor provides a normal temperature signal which indicates that the pressurized oxygen has stopped flowing. By way of example, the flow sensor  56  may alternatively be a pressure sensor to detect flow of oxygen to the apparatus  10  by comprising a transducer which detects pressure changes. For example, the flow of pressurized oxygen causes a differential pressure to arise. However, when the flow stops, the transducer provides a zero-pressure differential signal. As described further herein, various electronically controlled valves are utilized to control the flow of oxygen between preselected ranges, for example between 0 and 4 liters per minute for delivery to the electronic vaporizer  54 . As described further herein, the electronic vaporizer  54  comprises the first chamber  25  and the second chamber  27  which allow vaporization of anesthetic agent by the oxygen supplied by the oxygen source  52  creating a vaporized anesthetic agent which, in turn, is mixed with oxygen to form anesthesia. Adjacent the vaporizer  54  and flow sensor  56  is the flush valve  40  which is arranged in a bypass configuration so that the oxygen from the oxygen source  52  does not pass through the vaporizer  54  and the flow sensor  56  before charging the remaining portions of the anesthesia delivery apparatus  10 . As previously indicated the flush valve  40  is used to charge and clear residual anesthesia or diffused anesthetic agent remaining within the anesthesia delivery apparatus  10 . 
         [0038]    Referring still to  FIG. 4 , once the oxygen passes through the electronic vaporizer  54  and flow sensor  56  the resultant anesthesia enters the lower housing  18 , shown in broken lines, which comprises a plurality of tubing, piping, fittings or the like for delivery to and from the patient as well as ducting between a lower housing and the absorber  38  and pop-off valve  30 . This movement of anesthesia to and from the patient defines a breathing circuit between the anesthetic delivery apparatus  10  and the patient. Specifically, the anesthesia enters the lower housing  18  and moves through a duct to the patient which the patient inhales through the inhalation check valve  32  ( FIG. 3 ). When the patient exhales, the exhaled gas comprising carbon dioxide and unconsumed anesthesia passes through the exhalation valve  34 . As indicated in the schematic, the exhaled gas moves in the direction indicated by arrows “A” through ducting in the lower housing  18  to a re-breathing bag  41  ( FIG. 2 ) which depends from a stem beneath the pop-off valve  30   FIG. 2 . The re-breathing bag  41  captures exhaled gas and further may be manually depressed by a doctor during the surgical procedure on the patient in order to provide a breath to the patient. During exhalation, the re-breathing bag  41  becomes filled at which time remaining exhaled gas or air is directed to the pop-off valve  30  and on to the scavenging system  35 . During a subsequent inhalation by the patient, the gas within the re-breathing bag  41  is pulled to the absorber  38  indicated by arrow B where remaining carbon dioxide is scrubbed. The figure depicts two lines extending between the absorber  38  and the re-breathing bag  41  for ease of description and understanding. However, it is well within the scope of the present invention that a single line may be utilized with two-way flow therein between the absorber  38  and the re-breathing bag  41 . Further, it should be understood by one of ordinary skill in the art that piping may be positioned outside the lower housing  18  and still extend between the indicated components. 
         [0039]    Once inside the absorber  38 , the carbon dioxide is scrubbed utilizing the plurality of pellets  39  to remove carbon dioxide from the exhaled gas. The remaining anesthesia is directed from the absorber  38  into the lower housing  18  to the patient for inhalation with the incoming anesthesia from the vaporizer  54 . Such a system is commonly referred to as a rebreathing system which decreases the amount of wasted anesthesia and is therefore a more efficient system for use in administering anesthesia during a surgical procedure. However, it is well within the scope of the present invention that the dual anesthetic chamber and touchscreen design may be utilized without the rebreathing circuit. For instance, in anesthetizing small animals like guinea pigs or mice a physician may choose not to utilize the rebreathing system because of the large volumes of gas stored in the system as compared to the small respiratory volume of the animal. Such large volumes vary the response time of changes to anesthesia flow which should be precise with such small patients. Thus it should be understood that the anesthesia delivery apparatus may allow for bypass of the rebreathing circuit. 
         [0040]    Also in fluid communication with the lower housing is the pop-off or bleed valve  30  which continually bleeds off exhaled anesthesia. During a surgical procedure gas is continually being added to the breathing circuit. In order to inhibit pressure build-up, some gas must be bled from the system. Thus, the bleed valve  30  is utilized. Since the re-breathing bag  41  fills before gas is directed to the bleed valve  30 , the bleed valve  30  receives the last portions of exhaled gases from the patient&#39;s lungs. Accordingly, this gas comprises higher concentrations of carbon dioxide since it is usually the last of the exhaled gases from the lungs. This also makes the system more efficient because the absorber  38  is scrubbing less carbon dioxide and therefore the scrubbing pellets  39  last longer. As previously indicated the pop-off or bleed valve  30  may be connected to a scavenger system  35  which includes either or both of a charcoal filter to scrub anesthesia from the gas being relieved at the pop-off valve  30  or a blower and tubing assembly in order to direct anesthesia from within the interior structure of a building to outside the structure for diffusion to atmosphere. 
         [0041]    Referring now to  FIG. 5 , a block diagram is shown indicating flow of oxygen through the electronic vaporizer  54  indicated by the broken line. Initially oxygen from the oxygen source  52  may pass through a filter  53  to remove any impurities over a preselected size, for example, fifty microns, before moving to the flow sensor  56 . Upon leaving the flow sensor  56  the oxygen enters the electronic vaporizer  54  which comprises three possible paths for the oxygen. According to the first path wherein the oxygen diffuses and vaporizes the first anesthetic agent in the first chamber  25 , the oxygen first flows through a precision orifice  62  and then through an electronically controlled valve  60  which is in electronic communication with the circuit board  50 . The orifice  62  is sized according to vaporization requirements of the first anesthetic agent. Vaporization depends on the type of agent, the temperature of the agent, and the volume of flow into the agent. The precision orifice  62  allows regulation of the volume of flow by providing a baseline for making adjustments and controlling concentrations. As indicated the touchscreen graphics display  22  may be utilized to open or close the valve  60  through a selected amount of time as indicated and selected on the display  22  in order to control the concentration of anesthetic agent. Accordingly, a solenoid or the like may provide for movement of the valve  60 . After passing through the precision orifice  62  the oxygen flows through a first check valve  64  which allows one directional flow to the first agent chamber  25 . Alternatively stated, the first check valve  64  prevents anesthetic agent from moving upstream from the electronic vaporizer  54 . As depicted in  FIG. 8 , once in the first chamber  25 , the oxygen moves through a tube to a porous diffusing portion which allows the oxygen to diffuse through the anesthetic agent in a bubble form causing vaporization. As the bubbles diffuse in the first anesthetic agent, for example isoflurane, and exit the chamber  25  carrying molecules of anesthetic agent, a vaporized anesthetic agent is produced. The vaporized anesthetic agent is then directed through a check valve  66  to mix with oxygen and form the anesthesia at the selected concentration. The check valve  66  inhibits anesthesia to flow backward to the chamber  25 . By utilizing the touchscreen graphics display  22 , the first chamber electronic valve  60  selectively controls oxygen flow causing either intermittent or continual flow to the chamber  25  depending on the settings input on the graphics display  22 . During this time, oxygen also flows through an electronic valve  80 , a precision orifice  82 , and a check valve  84 . The pipe in fluid communication with the valve  80 , orifice  82 , and check valve  84  is also in fluid communication with the pipes comprising the first chamber  25  and the second chamber  27  and therefore defines an output for the vaporizer  54 . The electronic valve  80  is in electrical communication with the graphics display  22  in order to open and close the valve  80  and provide a desired flow rate of oxygen. The valve  80  may include a solenoid to provide opening and closing of valve  80 . The diffused anesthetic agent from the first chamber  25  and the oxygen mix before exiting the electronic vaporizer  54  and define an anesthesia of a preselected concentration measured as percent anesthetic agent by volume of total oxygen flow. 
         [0042]    According to a second flow path, the oxygen may flow through a second electronically controlled valve  70  in order to pass through the second chamber  27 . Like the first electronic valve  60 , the second electronically controlled valve  70  is in electrical communication with the circuit board  50  and therefore may be controlled by the touchscreen graphics display  22 . Such control also allows the valve  70  to be opened or closed according to the concentration of anesthesia required during the surgical procedure. Once the electronically controlled valve  70  is opened the oxygen passes through the precision orifice  72  and to the valve  70 . As previously indicated, the precision orifice  72  is sized according to the dimensions required for vaporization of the anesthetic agent. After passing through the valve  70  the oxygen then passes to the second chamber  27 . The second chamber  27  may include, for instance, sevoflurane which may commonly be utilized with isoflurane during a surgical procedure. After the oxygen bubbles through the second chamber  27  and is diffused in order to produce a diffused anesthetic agent, the diffused agent passes through a check valve  76  and mixes with oxygen passing through valve  80  to form an anesthesia. The check valve  76  also inhibits back flow to the second chamber  27 . The anesthesia passes from the electronic vaporizer  54  at a preselected concentration measured as percent by volume and indicated on the graphics display  22 . Alternatively, both the first valve  60  and the second valve  70  are opened in order to allow diffused anesthetic agent to be produced from both the first chamber  25  and the second chamber  27 . Such configuration is desirable when both chambers comprise the same anesthetic agent or if two agents need to be mixed for use during a surgical procedure. 
         [0043]    According to a third possible flow path, pure oxygen may be administered to a patient prior to a surgical procedure to saturate the patient&#39;s body with oxygen. According to an alternate scenario, the pure oxygen may be administered following the surgical procedure in order to bring the patient out from the anesthetic effects. In order to provide pure oxygen to a patient, the electronically controlled valves  60 , 70  are closed and the electronically controlled valve  80  is opened to a selected flow rate, as indicated on the graphics display  22 . In fluid communication with the electronically controlled valve  80  is an orifice  82  and a check valve  84  which all direct flow from the oxygen source to the lower housing  18  and on to the patient. As shown in  FIG. 5 , by closing valves  60 ,  70  and opening valve  80 , only oxygen is output from the vaporizer  54 . It should be understood that the various signals sent to the electronically controlled valves  60 , 70 ,  80  may be part of feedback control loops in order to control the dynamic behavior of the system. In addition, such a feedback control loop allows better accuracy in maintaining constant output percentage of anesthesia. 
         [0044]    Referring now to  FIG. 6 , an electrical block diagram generally indicates the various electrical connections utilized in the electronic anesthesia delivery apparatus  10 . The circuit board  50  ( FIG. 3 ) comprises an input/output (I/O) portion  87  comprising a plurality of inputs and outputs with various components of the electronic anesthesia delivery apparatus  10 . The I/O portion  87  of the circuit board  50  provides a signal to an inverter  22   a  which operates a back light (not shown) for the touchscreen graphics display  22 . Specifically the inverter  22   a  steps up the 5 volt DC signal to a several hundred volts in order to illuminate a backlight for the graphics display  22 . The I/O portion  87  also provides a signal to a display controller board  23  based on signals input from various other measuring and signal components in communication with the I/O portion  87 . The display controller board  23  comprises a video card and flash memory to produce the graphical user-interface which indicates the operating conditions and parameters, however various components may be utilized to produce graphical user-interface on the graphics display  22 . The signal received from the I/O portion  87  is graphically produced on the display  22  by the display controller board  23 . 
         [0045]    The first and second chambers  25 , 27  comprise sensors which are in electrical communication with the I/O portion  87 . The first chamber  25  and the second chamber  27  each comprise a temperature sensor (not shown) which sends a temperature signal  63  to the I/O portion  87 . The temperature sensor measures the agent temperature and is important because the anesthetic agent changes temperature during vaporization. This temperature change affects further vaporization and must be compensated for. Such compensation is made by algorithms on the circuit board  50  for instance by a processor or microprocessor. Accordingly, a temperature measurement must be made. 
         [0046]    In addition to the temperature signals delivered to the I/O portion  87 , an agent level signal  65  is also delivered from the first and second chambers  25 , 27 . As described further, the touchscreen graphics display  22  indicates the amount of anesthetic agent in each of the first and second chambers  25 , 27 . According to one embodiment a capacitance sensor may be utilized to provide a signal to the I/O portion  87 . With the agent level signal  65  received from the capacitance sensors the levels of the chambers  25 , 27  are visually indicated on the display  22 . This prevents running out of anesthetic agent during a surgical procedure. 
         [0047]    The I/O portion  87  also receives a signal from an apnea adapter  89  which comprises a thermistor positioned in the breathing passageway of the patient. The adapter  89  sends a signal based on temperature differences measured when the patient breathes. For example, the temperature will raise during exhalation and will drop during inhalation. If the I/O portion  87  fails to receive a signal from the apnea adapter  89  within a preselected time period, the processor concludes that the patient is not breathing properly and an alarm may sound from a speaker  90 . 
         [0048]    The I/O portion  87  may also receive a signal from a remote infrared receiver  91 . The electronic anesthesia delivery apparatus  10  may also comprise a remote control or transmitter  93  which sends an infrared signal to the remote infrared receiver  91  which in turn communicates with the I/O portion  87 . The remote control  93  may communicate with the receiver  91  to increase or decrease oxygen flow rates by controlling valve  80  or increase or decrease flow rates of oxygen through the first and second chambers  25 , 27  thereby controlling rates of vaporization and therefore concentrations of anesthetic agent in anesthesia. 
         [0049]    The I/O portion  87  also receives a signal from a breathing circuit pressure sensor  92 . The breathing circuit pressure sensor  92  is also measured at the breathing passageway of the patient and is utilized to measure the breathing pressure of the circuit so as not to harm the patient and further to insure enough pressure is present to deliver anesthesia to the patient. If the breathing circuit pressure falls outside a preselected range the signal may cause an alarm which notifies a physician through the speaker  90 . 
         [0050]    The I/O portion  87  also receives a signal from the flow sensor  56  indicating flow of oxygen into the electronic vaporizer  52 . If the flow sensor  56  sends a signal that flow is not available, an alarm may sound through the speaker  90  indicating to a user that the condition should be corrected. 
         [0051]    The apparatus also comprises AC or DC power capability. The device may receive AC power from 110 or 230 volt source. Alternatively, the device may be operated from a DC battery power supply. In addition to these power sources, the device  10  may further comprise a battery backup in an AC power supply is lost during a surgical procedure. 
         [0052]    Referring now to  FIG. 7 , a front view of the touchscreen graphics display  22  is shown which comprises the graphical users interface. The interface depicted on the display  22  allows the user to control various components of the electronic anesthesia delivery apparatus  10 . At the upper left hand corner of the display  22  is a real time clock  100  which may display 12-hour time or 24-hour time as depicted. Adjacent the real time clock  100  is an agent identification (ID) window  102  which indicates “None”. By pressing the agent ID window  102  and the up/down toggles  106 ,  108 , the agent ID toggles through the selections “None”, the first anesthetic agent, for example “Isoflurane”, and the second anesthetic agent, for example “Sevoflurane”. The window  102  may also change color according to the corresponding color code for the drug indicated. When the first anesthetic agent is displayed in the agent ID window  102 , the toggles  106 , 108  are utilized to control concentrations of that anesthetic agent. Alternatively, when the second anesthetic agent is highlighted in the agent ID window  102  the toggles  106 , 108  are utilized control changes to the second anesthetic agent. Thus, the toggles  106 ,  108  control movement of the electronic control valves  60 , 70  thus varying the concentration of the diffused anesthetic agent. By pressing the agent ID button  102  again, the ID returns to “None” as depicted. Thus the user presses the agent ID window  102  and toggles through the selections until the desired agent may be controlled. 
         [0053]    Beneath the clock  100  and the agent ID  102  is a virtual concentration setting  104  which depicts a percent by volume of an agent which is highlighted in the agent ID window  102 . For example, when the first anesthetic agent is highlighted in the agent ID window  102 , the concentration of the first anesthetic agent is shown in the concentration setting  104 . The same condition occurs when the second anesthetic agent is highlighted in the agent ID window  102 . When a desired agent is selected, the corresponding concentration setting  104  may be adjusted for that anesthetic agent. The concentration being output for each anesthetic agent  104  is measured in percent of anesthetic agent by volume and may range, for example, up to about 10 percent. 
         [0054]    Beneath the concentration setting  104  is a digital pressure gauge  110  which records pressure within the breathing system. For example, the digital gauge may be a virtual analog gauge and as depicted, the digital gauge  110  is circular in shape with a digital needle indicating the pressure within the breathing system. The digital pressure gauge  110  receives a signal via the I/O portion  87  from the breathing circuit pressure sensor  92  ( FIG. 6 ). As previously indicated, the breathing circuit pressure sensor  92  ( FIG. 4 ) is located as close to the patient as possible to obtain accurate readings of pressure at the patient. The gauge  110  is shown indicating pressure in centimeters of water. 
         [0055]    Along the left hand side of the touchscreen graphics display  22  is a virtual first level indicator  114  for the first anesthetic agent in the first chamber  25 . The first level indicator  114  receives a signal via the I/O portion  87  from the agent level signal  65  ( FIG. 6 ). By indicating the level of agent in the first chamber  25 , the user knows when a refill of anesthetic agent is necessary prior to starting a procedure. This is particularly useful so that a chamber does not empty during a procedure which would require refilling and could harm the patient. On the right hand side of the touchscreen display  22  is a virtual second level indicator  116  which indicates the level of second anesthetic agent in the second chamber  27 . The first and second level indicators  114 , 116  may both include bars indicating agent levels or may include virtual moving indicators which move along a level bar as depicted. 
         [0056]    Beneath the pressure gauge  110  is an octagonal shape which indicates a stop button  112  for the anesthesia delivery apparatus  10 . The stop button  112  is pressed when a procedure is finished and the anesthesia delivery is no longer needed. The stop button  112  may be colored red on the display  22  which is commonly recognized as a stop signal. Also beneath the breathing pressure gauge  110  is a case clock  118  which may be used by a physician to bill for time on a particular surgical procedure or to bill for amount of anesthesia utilized. The case clock  118  may be stopped by pressing the stop button  112 , thus marking the time of the surgical procedure. 
         [0057]    In the middle of the touchscreen display  22  is a virtual oxygen flow meter which receives a signal from a flowmeter and indicates the total flow of oxygen being delivered from the electronic vaporizer  54 . Alternatively, the electronic control valve  80  may cycle on and off and utilizing known cycle rates with an algorithm, the oxygen flow rate may be ascertained and displayed. Although various flow rates may be utilized, the present exemplary embodiment comprises a design which delivers up to 4 liters of oxygen per minute. At a lowermost position of the oxygen flowmeter  120  is a start button  122  which starts oxygen flow to the patient to begin a procedure. The start button  122  may be colored green to indicate a start function to a user. Once the button  122  is depressed, the oxygen flow may be increased using toggle button  108  or decreased using toggle button  106  as will be indicated on the flowmeter  120 . The toggle buttons  106 , 108  are therefore controlling the electronic control valve  80  in order to vary the oxygen flow through the system. 
         [0058]    Also shown on the touchscreen graphics display  22  is an alarm or warning screen  124 . The alarm screen  124  provides a visual indication to a user that an alarm condition has been triggered. For instance, the apnea adapter or sensor  89  may be triggered by a lack of breath from the patient after a preselected amount of time, or the flow sensor  56  may cause an alarm if oxygen from the source  52  is not flowing. Thus, in addition to the audible alarm signal provided by the speaker  90 , the alarm screen  124  may provide a visual indication of an alarm condition which should be corrected. 
         [0059]    Beneath the alarm screen  124  is a configuration button  126  which allows a user to configure various settings, alarm conditions and the like. Adjacent the configuration button  126  is an mute or override button  128  which silences the audible alarm for a preselected period of time. For example, if an alarm sounds a user may press the override button  128  which cancels the audible alarm from speaker  90  for an adjustable time period of, for example, 2 minutes. This muted time period is also a period which may be set utilizing the configuration button  126 . After, the two minute period, if the alarm condition is not corrected, the alarm will sound again. 
         [0060]    Alternatively to the touchscreen graphical display  22 , a plurality of devices may be utilized. For instance, a graphics screen such as an LCD or CRT monitor may be used in combination with a separate touchpad or keypad programmed for use with the anesthesia device. Further, a trackball or mouse-type pointing device may be utilized with the display to make selections and adjustments to the system. Accordingly, such embodiments should be understood to be within the scope of the present disclosure. 
         [0061]    As further alternatives, the anesthesia delivery apparatus  10  may include a carbon dioxide (CO 2 ) sensor or monitor  94  to measure CO 2  levels and so that the apnea sensor will not be needed or may be replaced. Additionally, a pulse oximetry sensor  95  may be utilized for measuring oxygen levels in the patient. Such sensor  95  is in electronic communication with the circuit board and may be output on the graphic display screen. Further, electrocardiogram (ECG) sensor  96  may be added to the apparatus  10  so that heart wave forms may be provided from the apparatus. The ECG measuring device  96  is also in electronic communication with the circuit board, and further comprises electrodes in electronic communication with the circuit board which are used to receive data and produce the electrocardiogram. Even further, a remote control  93  functionality may be utilized with the touchscreen or display which allows for movement of a cursor or selector about the screen and may include at least one button to make selections shown in the screen. As a further alternative, an input  97  for a flashcard may be provided to allow for flash re-programming or additional programming for new or different anesthetic agents. The flashcard and input would be in communication with the circuit board and input/output portion of the apparatus  10 . As a further option or alternative to this input, a USB port  98  may be utilized instead of or in addition to the flashcard input so as to allow connection to a computer or other device and allow for the previously described additional programming or re-programming of code related to algorithms for the various anesthetic agents which are available now or may be available in the future. Such USB port would also be in communication with the input/output portion  87  and the circuit board to allow for remote-troubleshooting or also allow downloading of surgical related data from use of the apparatus  10 . Additionally a network connector  99 , wired or wireless, may also be used to connect the apparatus  10  for troubleshooting or updates. Standards for connectivity will be known to one skilled in the art. 
         [0062]    In operation a carrier gas source, for example a 50 psi oxygen source, is connected to an inlet port. The anesthesia delivery apparatus  10  is connected to an A/C power source and powered on. Initially, various electronics and components of the apparatus  10  will go through a self-test to verify proper function. The alarm screen  124  will display the progress of this test and pass/fail information will be posted. If any component fails the unit will be put in permanent failsafe mode or for some non-critical test the user can continue by pressing an override mode key (not shown) or key combination. Alternatively, when the self-test is successfully completed the apparatus  10  will go into ready status waiting on user input. 
         [0063]    Next the physician or an assistant can connect their external disposable breathing hoses to the patient and the ports  33 , 35 . The physician next touches the virtual oxygen flow control start button  122  at which time the virtual flowmeter  120  will become highlighted or illuminated indicating the microprocessor is ready for increments or decrements to set the flowrate. The physician increases the flow to a desired setting by pressing the up toggle  108 . Next the apparatus begins immediately delivering oxygen upon selection of an oxygen flow greater than 0. The case clock  118  begins timing when the oxygen flow begins. 
         [0064]    Once the correct oxygen flow is achieved the user then touches the anesthetic agent selection box  102 . This will highlight. The physician would then press the up or down arrows to cycle through the selections of the first anesthetic agent, for example isoflurane, the second anesthetic agent, for example sevoflurane, and the none selection. Other drugs or drugs developed in the future may be programmed into the system. Once the desired anesthetic agent is displayed, the physician touches the concentration setting window  104  to select the output concentration of agent desired. The window  104  will highlight and the physician uses the toggles  106 , 108  to select the percentage of agent. Next the anesthesia begins delivery upon choosing a percentage greater than 0. 
         [0065]    During operation the virtual pressure gauge  110  displays the patient lung pressures being realized. Sensors monitor these pressures as well as breath detections, agent percentage settings and many other safety related parameters. If any of the sensors detect an unsafe condition, an alarm may sound. At any time the physician can adjust the carrier gas flow settings or by pressing the stop button  112  on the display  22  can cease all flows and stop the case clock. By pressing the stop button  112  the delivery apparatus  10  “ends the case” and is put into standby mode. By pressing anywhere on the display  22  the unit can be re-activated and ready for input. The override or mute virtual button  128  may be pressed to silence the alarms for 2 minutes. Further, alarm conditions are displayed on the alarm screen  124 . The unit is intended to be left on and go into a sleep mode however, the physician or an assistant may turn off and on each day if they desire. 
         [0066]    The foregoing description of several methods and an embodiment of the invention have been presented for purposes of illustration. It is not intended to be exhaustive or to limit the invention to the precise steps and/or forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be defined by the claims appended hereto.