Electronic vaporizer system and method of controlling the same

Abstract

This invention provides an electronic vaporizer system comprising: an anesthetic reservoir containing an anesthetic; a vaporizer unit that vaporizes the anesthetic from the reservoir and delivers the vaporized reagent to a patient's breathing circuit; and a gas sensor configured to measure the end-tidal concentration of the anesthetic in the patient's exhaled breath. A control system is configured to receive the measured end-tidal concentration of the anesthetic and compare it with a desired end-tidal concentration that the patient wishes to maintain. Then, based on the comparison, the vaporizer unit is automatically controlled to deliver a predetermined amount of vaporized reagent to the patient.

Description

Background Technology

[0001] This disclosure relates generally to anesthetic delivery systems, and more specifically to vaporizer systems for delivering vaporized anesthetics to a patient’s breathing circuit.

[0002] Anesthetics induce a hypnotic state in patients through the administration of such drugs, such as by inhalation via the patient's breathing circuit. Typical inhaled anesthetics include sevoflurane, isoflurane, desflurane, and enflurane. These inhaled anesthetics are generally stored in liquid form and then vaporized in a vaporizer system. The vaporized anesthetic is mixed with fresh gas and other ventilation gases delivered to the patient. Various types of anesthetic vaporizers are well known in the field, including pressurized vaporizers, distilled vaporizers, and dual-circuit gas-vapor mixers.

[0003] Anesthetics act on the brain, causing a decrease or loss of consciousness in the patient. The degree to which a patient is anesthetized is commonly referred to as "depth of anesthesia" or "hypnotic level." Various patient monitoring devices can be used to measure the depth of anesthesia, such as a bispectral index (BIS) monitor, which analyzes the complexity of electroencephalogram (EEG) data obtained from the patient as an indicator of the sensed hypnotic level. Other methods and systems for monitoring the depth of anesthesia are also known, including four-stack stimuli monitors, facial twitching monitors, etc. Summary of the Invention

[0004] This summary is provided to introduce a series of concepts that will be further described in the detailed embodiments below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help limit the scope of the claimed subject matter.

[0005] In one embodiment, an electronic vaporizer system includes: an anesthetic reservoir containing an anesthetic; a vaporizer unit that vaporizes the anesthetic from the reservoir and delivers the vaporized reagent to a patient's breathing circuit; and a gas sensor configured to measure the end-tidal concentration of the anesthetic in the patient's exhaled breath. A control system is configured to receive the measured end-tidal concentration of the anesthetic and compare it with a desired end-tidal concentration that the patient wishes to maintain. The vaporizer unit then automatically controls the delivery of a controlled amount of vaporized reagent to the patient based on the comparison.

[0006] In one embodiment, a method of controlling a vaporizer system configured to vaporize an anesthetic agent and deliver the vaporized agent to a patient's breathing circuit includes: measuring an end-expiratory concentration of the anesthetic agent in the patient's exhaled breath; and comparing the measured end-expiratory concentration with a desired end-expiratory concentration to be maintained by the patient. The vaporizer unit is then automatically controlled based on the comparison to deliver a predetermined amount of the vaporized agent to the patient's breathing circuit to maintain the measured end-expiratory concentration within a predetermined range of the desired end-expiratory concentration.

[0007] Various other features, objects, and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings. Attached Figure Description

[0008] This disclosure is described with reference to the following figures.

[0009] Figure 1 An implementation of an electronic vaporizer system connected to a ventilator system to deliver anesthetic to a patient is described.

[0010] Figure 2 Another embodiment of an electronic vaporizer system connected to a ventilator system to deliver anesthetic to a patient is described.

[0011] Figure 3 An exemplary table is depicted for calculating the recommended end-tidal concentration of the exemplary anesthetic sevoflurane based on patient demographics and other information.

[0012] Figures 4 to 6 A method or part thereof for controlling an electronic vaporizer system for delivering anesthetic to a patient is described. Detailed Implementation

[0013] As described above, the vaporizer inhales a liquid anesthetic (such as sevoflurane or desflurane) and converts it into vapor, which is then titrated to the patient. The patient inhales the anesthetic vapor via breathing gas delivered by a ventilator. Mechanically controlled vaporizer systems are a very common type of vaporizer system worldwide. Mechanical vaporizers are open-loop control systems, where clinicians set the delivery volume of the vaporizer, for example, by controlling a dial on the vaporizer system's housing. Depending on the patient's needs and the desired depth of anesthesia or hypnotic level, and based on the medical care provided to the patient, the clinician manually adjusts the delivery volume of the agent delivered by the manual vaporizer.

[0014] The inventors have recognized the problems with manual vaporizers, which require a great deal of attention and resources from clinicians to operate them correctly and deliver the optimal dose of anesthesia to patients. Furthermore, open-loop control systems are susceptible to human error; in such cases, busy clinicians may be distracted and unable to provide optimal ventilator control settings and timing, resulting in patients receiving too little or too much anesthesia at any given point in the medical protocol. However, the inventors also recognize that many nursing facilities may not be able to purchase new anesthesia delivery and ventilation systems that offer closed-loop control.

[0015] Furthermore, the inventors have recognized that controlling anesthesia delivery based on the end-tidal concentration of the anesthetic in the patient's exhaled breath would provide an effective closed-loop control mechanism, and such closed-loop control is desirable and overcomes problems related to human capital and clinician error.

[0016] In view of the aforementioned challenges in the relevant field recognized by the inventors, the inventors have developed the disclosed electronic vaporizer system, which can be retrofitted into existing ventilator systems, such as ventilator systems with circulatory breathing systems, to provide anesthesia delivery capabilities. The disclosed electronic vaporizer system replaces the mechanical vaporizer in existing anesthesia systems and is therefore configured to connect to the patient's breathing circuit in the same manner as existing mechanical vaporizers. That is, the mechanical vaporizer can be removed and replaced with the disclosed closed-loop control electronics system. In some embodiments, the shape and size of the electronic vaporizer system can be set similarly to the mechanical system, such that it can be mounted onto the housing of the anesthesia system, with the mounting location and / or connection means being the same as in the manner in which the mechanical ventilator is replaced.

[0017] An electronic vaporizer system is configured to receive a measured end-expiratory concentration (EEDC) of an anesthetic agent delivered by the vaporizer and compare the measured EEDC with a desired EEDC that the patient wishes to maintain. For example, the desired EEDC may be, for instance, a minimum alveolar concentration (MAC) value and may also include end-expiratory CO2 and / or O2. The desired EEDC may be set by a clinician or may be automatically set and controlled by the electronic vaporizer system, such as according to predetermined routine values. Based on the comparison between the measured EEDC and the desired EEDC, the electronic vaporizer system automatically delivers a specific amount of vaporized reagent to the patient. For example, the electronic vaporizer system may determine a variation in the amount of vaporized reagent to be delivered to the patient's breathing circuit based on the difference between the measured EEDC and the desired EEDC, and control the vaporizer to achieve this variation in order to maintain the measured EEDC within a predetermined range of the desired EEDC.

[0018] In some implementations, the electronic vaporizer system may include and / or be communicatively connected to an anesthesia depth monitor (such as a BIS monitor or four cascade stimulation monitors) configured to measure the patient's anesthesia depth. The electronic vaporizer system may be configured to utilize the anesthesia depth information to provide further closed-loop control to maintain the patient at a desired anesthesia depth. For example, the electronic vaporizer system may be configured to set a desired end-expiratory concentration (EEDC) or determine changes in the desired EEDC to achieve or maintain the desired anesthesia depth. The system then uses the measured EEDC as feedback to control the delivery of the vaporizing agent based on the set desired EEDC.

[0019] The system can be further configured to receive and / or follow one or more conventional concentration values ​​that provide end-expiratory concentration values ​​over time, and automatically adjust the desired end-expiratory concentration over time based on these conventional values. For example, the system can be further configured to calculate a recommended anesthetic concentration based on patient demographics, inform the clinician of this recommendation, and / or automatically adjust the desired end-expiratory concentration based on this recommended concentration. This allows for automatic control of the transition periods of anesthetic delivery (such as induction and recovery) to maintain the patient's end-expiratory concentration at a predetermined desired level over time. This provides safe and precise anesthetic control during critical periods and allows clinicians to focus on other areas of patient care.

[0020] Figure 1 and Figure 2 An embodiment of an electronic vaporizer system 10, operatively connected to a ventilator system 2 and configured to deliver vaporized anesthetic to a patient's breathing circuit 4, is described. The electronic vaporizer system 10 includes an electronic vaporizer 12 and one or more sensors communicatively connected to the electronic vaporizer, the sensors including: a gas sensor 50 configured to measure the end-tidal concentration of the anesthetic in the patient's exhaled gas; and one or more physiological sensors 44 configured to measure physiological signals relating to or indicating the depth of anesthesia in the patient. The electronic vaporizer 12 is configured to receive the measured end-tidal concentration of the anesthetic and / or the depth of anesthesia in the patient determined based on the physiological signals, and accordingly fundamentally control the delivery of the vaporized agent to the patient.

[0021] The electronic vaporizer 12 includes a reservoir 16 containing an anesthetic agent, such as sevoflurane, desflurane, enflurane, etc., to be delivered to a patient. The reservoir 16 is configured to be refillable, such as from a refill bottle, which is standard practice in the relevant field. Therefore, the reservoir 16 has sufficient volumetric capacity to receive at least the full volume of a standard refill container. In one embodiment, the reservoir can hold up to about 300 mL of liquid reagent. The electronic vaporizer 12 includes a vaporizer unit 14 that vaporizes the liquid anesthetic agent contained in the reservoir 16 and delivers the vaporized reagent to the patient's breathing circuit 4. For example, the breathing circuit 4 may include a recirculatory system 3, and the vaporizer unit 14 may be configured to deliver the vaporized reagent such that an inhaled gas containing the anesthetic agent is injected into the recirculatory system 3 and delivered to the patient by a ventilator system 2.

[0022] The electronic vaporizer 12 also includes a controller 18 configured to control the vaporizer unit to deliver a predetermined amount of vaporized reagent, thereby maintaining a desired end-tidal concentration for the patient 1. The control system of the electronic vaporizer system includes the controller 18 for the vaporizer unit 14 and may also include other control devices communicatively connected to the controller 18. For example, the controller 18 may cooperate with an anesthesia calculation module 66 communicatively connected to a network 60 of the electronic vaporizer 12 and / or a controller (such as a BIS monitor 40a) associated with an anesthesia depth monitor 40 and / or a controller 8 for the ventilator system 2.

[0023] Gas sensors (which may be a set of sensors) are positioned to measure the end-tidal concentration of anesthetic and other gases in the exhaled gas within the patient breathing circuit 4. The patient breathing circuit 4 includes an inspiratory section 4a that delivers inhaled gas from the ventilator system to the patient interface 6. An expiratory section is configured to deliver exhaled gas back from the patient to the ventilator 2. For example, the patient interface is typically an endotracheal tube, such as... Figure 2 As shown. In other embodiments, the patient interface 6 may be a mask or some other device configured to form a sealed interface between the patient's airway and the breathing circuit 4. In the depicted example, the gas sensor 50 is positioned between the patient interface 6 and the inspiratory and expiratory arms of the patient's breathing circuit 4. A humidity and moisture exchange filter 59 may be positioned between the patient interface 6 and the gas sensor 50 to remove moisture from the exhaled air prior to measurement.

[0024] The gas sensor is configured to measure the concentration of an anesthetic in the patient's exhaled gas, and may also be configured to measure the concentrations of nitrous oxide (N₂O), carbon dioxide (CO₂), and oxygen (O₂). Such concentration measurements are performed during the expiratory cycle, wherein exhaled gas is expelled from the patient's lungs through the patient interface 6, passes through a filter 59, reaches a first connector end 57 of the unit containing the gas sensor 50, and flows out from a second connector end 56, which connects to a connector end 4c of the patient's breathing circuit tubing. The gas sensor 50 may be further configured to measure flow rates, including inspiratory and expiratory flow rates, as well as other gas concentration measurements, which may be inspiratory or expiratory measurements.

[0025] Concentration and other measurements from gas sensor 50 can be transmitted to electronic vaporizer 12, which can be done via physical data connection and / or wirelessly. Figure 2 In this example, gas sensor 50 is connected via cable 52 to receiver port 53 on electronic vaporizer 12. Gas sensor 50 also includes a wireless transmitter 54 that can communicate with wireless transceiver 42a, configured to wirelessly broadcast concentration measurements and other measurements taken by gas sensor 50. Such wireless communication can be received by network 60 (such as a computer network system for operating rooms) and / or by a hospital or healthcare facility network. In some embodiments, concentration and / or other gas measurements may also be received at an anesthesia depth monitor 40. In some embodiments, the physical connection between gas sensor 50 and electronic vaporizer 12 may be eliminated, and electronic vaporizer 12 may be configured to receive wireless transmissions of measurement results from gas sensor 50.

[0026] An additional gas sensor 9 may be configured to measure the input gas from the ventilator to the patient's breathing circuit and to measure the ventilation gas mixture provided by the ventilator 2. This gas sensor 9 may be located upstream of the vaporizing agent delivery point and may be configured to measure the flow rate and gas concentration of the ventilator gas mixture, such as oxygen (O2) and N2O in the ventilator gas mixture. This provides information about the input gas and flow rate provided by the ventilator system. In some embodiments, the gas sensor 9 may be integrated into the ventilator system 2, and the gas measurement results may be transmitted from the ventilator system 2 to the electronic vaporizer 12. In other embodiments, the gas sensor 9 may be a standalone sensor connected at a point in the breathing circuit and configured to communicate directly with the electronic vaporizer 12, which may communicate via wired or wireless means as described above. Input gas concentration information may also be supplied by an electronic gas mixer built into the anesthesia machine, if such a configuration is used. For example, an additional gas sensor 9 may be integrated into an electronic gas mixer that automatically mixes and delivers the gas mixture to the patient's breathing circuit (N2O / O2, air / O2, O2, or air). In such embodiments, the gas composition is obtained from the electronic gas mixer via communication with it, which may be wired or wireless communication as described herein.

[0027] System 10 may also include an anesthesia depth monitor 40, which is configured to measure the patient's depth of anesthesia. Various anesthesia depth monitors are well known in the relevant field, including bispectral index (BIS) monitors, four-stack stimulus monitors, facial twitching monitors, etc. Figure 2 In this example, the anesthesia depth monitor 40 is a BIS monitor 40a. The BIS monitor includes a physiological sensor 44, which is in the form of an EEG electrode 44a strip, configured to be placed on the forehead of patient 1 and to measure the patient's EEG activity. The BIS monitor 40a is configured to determine the patient's anesthesia depth or hypnotic level.

[0028] exist Figure 2 In the example shown, the BIS monitor 40a is a standalone device with a housing 41, and EEG electrode patches 44a are connected to a receiver port 47 on the housing 41 via a cable 45a. The BIS monitor includes a user interface display 42 configured to display and collect anesthesia depth EEG information. The system 10 is configured such that the anesthesia depth information collected by the BIS monitor 40a is transmitted to the electronic vaporizer 12. In some embodiments, the BIS monitor 40a includes a wireless transmitter or transceiver 48 configured to wirelessly transmit anesthesia depth and / or EEG information. The wireless transmission can be received at the electronic vaporizer 12.

[0029] For example, a wireless communication link 49 can be established between the electronic vaporizer 12 and the BIS monitor 40a, i.e., between the I / O communication transceiver 19 and transceiver 48, for transmitting anesthesia depth information. Such communication can be performed via any wireless communication protocol, such as Bluetooth, Bluetooth Low Energy (BLER), ANT, and ZigBee. Alternatively, the wireless transceivers of the BIS 40a and the electronic vaporizer 12 can communicate with each other via a remote wireless system, such as a network operating on the Wireless Medical Telemetry Service (WMTS) spectrum or on a WiFi-compatible wireless local area network (WLAN). In other embodiments, the BIS 40a and the electronic vaporizer 12 can be body area network (BAN) devices operating as wireless networks for wearable or portable computing devices, such as medical body area network (MBAN) devices.

[0030] Alternatively or otherwise, the electronic vaporizer system 10 may be configured to communicate with and receive communications from a hospital computer network, which may be a wireless or wired communication device. Network 60 may include an anesthesia calculation module 66, which can be executed to communicate with the electronic vaporizer 12 and monitor the anesthesia delivery routine values ​​and instructions being executed by the system. System 10 may be configured to also receive anesthesia depth information at the hospital network 60 and to transmit this anesthesia depth information from network 60 to the electronic vaporizer 12. Figure 2 In the example, the electronic vaporizer 12 communicates with network 60 via wireless link 64, and the BIS monitor communicates with network 60 via wireless link 62. For example, network 60 may be a local area network of the operating area of ​​a hospital or other medical facility.

[0031] In one arrangement, the electronic vaporizer 12 and / or BIS 40a may be configured as edge devices operating in an edge computing system, where, for example, a central computer system in a surgical department of a healthcare facility collects and analyzes patient and ventilation data to monitor and guide the end-expiratory delivery of anesthetics to the patient. For example, the electronic vaporizer 12, the anesthesia depth monitor 40, and the gas sensor 50 may all be edge devices that transmit and receive information from one or more edge servers forming part of network 60.

[0032] In other embodiments, the BIS monitor 40a or other anesthesia depth monitor 40 may be integrated within the housing 20 of the electronic vaporizer 12. For example... Figure 1As shown, the anesthesia depth monitor 40 may be integrated with the controller 18 or housed within the vaporizer unit 14, reservoir 16, and other components of the electronic vaporizer 12. In such embodiments, physiological sensors 44 (such as EEG patches 44a or four serial stimulation sensors) are connected to the housing 20 of the electronic vaporizer 12 via a communication link 45. The communication link 45 may be wired or wireless, examples of which are described above. In such embodiments, the anesthesia depth monitor 40 may include a dedicated controller for calculating anesthesia depth values. In other embodiments, the controller 18 may be configured to calculate anesthesia depth values ​​based on physiological data collected and filtered by the anesthesia depth monitoring electronics.

[0033] The housing 20 of the vaporizer system 12 can be configured to be removably attached to the ventilation system 2. For example, the housing 20 can be configured to connect to an existing ventilation system 2, replacing an existing manual vaporizer. Thus, the housing 20 can be shaped similarly to the manual vaporizer system being replaced, or at least a portion of the housing connected to the ventilation system 2 can be shaped and configured similarly or identically to an existing manual vaporizer housing. Consequently, the disclosed electronic vaporizer system 10 can replace an existing manual vaporizer in various installed ventilation systems 2.

[0034] The housing 20 may include a refill port 22 configured to receive a refill container for anesthetic to refill the reservoir 16. A dial 24 may also be provided on the housing 20. The dial 24 may be configured to control modes of the vaporizer system, wherein the dial 24 is movable between a position associated with a manual mode and a position associated with an automatic mode, in which the clinician manually controls the amount of vaporizer delivered to the patient's breathing circuit, and in which the control system automatically controls the vaporizer unit to deliver a predetermined amount of vaporizer to maintain a certain end-tidal concentration of anesthetic for the patient. Figure 2 In the depicted example, the automatic mode position 25 is located at the far end of the rotation range of the dial 24. When the dial 24 is at this maximum rotation position, the automatic mode mark 25 is aligned with the selection mark 28 on the housing 20. When the dial rotates away from the automatic mode position 25, a manual mode is activated, in which the clinician can operate the dial to select the end-expiratory concentration. Various position indicators 26 are associated with corresponding concentration outputs, and the vaporizer unit 14 is controlled accordingly, similar to existing manual vaporizer controls on manual vaporizer systems. Therefore, the depicted electronic vaporizer 10 is also configured to operate as a manual vaporizer when neither the automatic mode nor the end-expiratory concentration control mode is selected.

[0035] In other embodiments, the dial 24 may alternatively be replaced by another user interface device for enabling and disabling the automatic mode, such as a switch or button configured to turn the automatic mode on and off, in which the control system automatically controls the vaporizer unit to maintain the patient's end-expiratory concentration. In still other embodiments, the automatic mode may be enabled via a user interface 30 associated with the electronic vaporizer 12. The user interface 30 may be a stand-alone device, such as a touchscreen housed separately from the housing 20 of the electronic vaporizer. Figure 1 As shown. In other implementations, such as Figure 2 As shown, the user interface 30a can be integrated into the housing 20 of the electronic vaporizer 12. The integrated interface 30a can be a touchscreen, such as an LCD touchscreen, on the clinician-facing side of the housing 20.

[0036] User interfaces 30, 30a are configured to display information related to anesthesia delivery and control, including: a reagent indicator 31 indicating delivery of anesthetic by the electronic vaporizer 12; a desired concentration indicator 33 displaying a desired end-expiratory concentration setting to be automatically maintained by the system 10; and a measured concentration indicator 34 indicating the currently measured end-expiratory concentration of the anesthetic for patient 1. In the depicted embodiments, the desired concentration indicator 33 presents the desired concentration setting as a minimum alveolar concentration (MAC) value, and the measured concentration indicator 34 presents the measured concentration as a volume percentage of the reagent in the patient's exhaled gas. In other embodiments, the measured concentration indicator 34 may present a MAC value and / or the desired concentration indicator may present a volume percentage value. The user interface may also display an N2O indicator indicating the end-expiratory concentration of N2O. Alternatively or additionally, the user interface may also display the inspiratory N2O concentration, such as that measured by the gas sensor 9 or the ventilator electronic gas mixer in the ventilator gas blend. The user interface may also include one or more patient demographic indicators 36, which provide demographic information about the patient 1, such as age, weight, gender, etc.

[0037] User interfaces 30, 30a can also be configured to display information, suggestions, and instructions to clinicians. For example, the display can be configured to provide clinicians with suggested concentrations based on patient demographics and / or to provide suggestions or instructions based on suggested concentrations to adjust the desired end-expiratory concentration. Alternatively or additionally, user interfaces 30, 30a can be configured to prompt clinicians to input and / or receive clinician input indicating desired end-expiratory concentrations and / or to input one or more concentration norms to be executed by the vaporizer system 12 over time. For example, a clinician can instruct the execution of a series of desired end-expiratory concentrations over a period of time at a specific stage of the procedure, such as induction norms for inducing a desired depth of anesthesia or hypnotic state in the patient and / or emergency norms for reducing the depth of anesthesia at a desired rate.

[0038] In some embodiments, the anesthesia calculation module 66 may be further configured to calculate recommended concentration values ​​and / or recommended conventional concentration values ​​for controlling the electronic vaporizer 12 based on patient demographic data and / or patient historical data, and to provide such recommended concentration values ​​or recommended conventional concentration values ​​to the electronic vaporizer 12. The anesthesia calculation module 66 may be configured to utilize the latest anesthesia calculation algorithms and information (including published MAC charts) as well as patient demographic information, medical history, etc., obtained from the patient's medical records to calculate and propose appropriate end-expiratory concentration settings and / or conventional values ​​to provide optimal anesthesia delivery to the patient. Figure 3 The image illustrates an exemplary MAC chart that provides a desired MAC setting based on exhaled oxygen, exhaled N2O, and patient age. In edge computing systems, such MAC charts and other information used to calculate recommended concentrations for desired end-expiratory settings can be easily updated at the network level, leveraging advancements in artificial intelligence (AI).

[0039] Figures 4 to 6 An exemplary method, or a portion thereof, for controlling an electronic vaporizer system is described. Figure 4 In the flowchart, the method 100 for controlling the electronic vaporizer system includes receiving a desired end-expiratory concentration at step 102. For example, the desired end-expiratory concentration may be input by a clinician, such as via a user interface 30, or may be automatically determined by the system, such as at a hospital LAN network, and indicated by the anesthesia calculation module 66. At step 104, the end-expiratory concentration of the anesthetic in the patient's exhaled gas is measured, for example, by a gas sensor 50. At step 106, the measured concentration is compared with the desired concentration. Then, at step 108, based on the difference between the measured end-expiratory concentration and the desired end-expiratory concentration, the vaporizer unit 14 is controlled to deliver the vaporized reagent.

[0040] Figure 5This describes a part of a control method for a vaporizer system relating to the calculation and implementation of recommended concentration values ​​or recommended concentration norms. As described above, the recommendation calculation can be performed at the network level, or the controller 18 of the electronic vaporizer 12 can be configured to perform the recommendation calculation. Information about the inhaled gas delivered to the patient and the current settings of the electronic vaporizer is provided, and this information is used to calculate the recommended concentration or norm, which is then provided as a recommendation to the clinician, who can accept or reject these recommendations. Alternatively, such recommendations can be implemented automatically by the electronic vaporizer 12.

[0041] exist Figure 5 In the example shown, the N2O concentration is received at step 110, which may include the inspiratory N2O concentration (ventilator gas blend) provided by the ventilator 2 and / or may include the end-expiratory N2O concentration measured by gas sensor 50. At step 112, the currently desired end-expiratory concentration and / or the current standard concentration value for the vaporizer setting is received. At step 114, a recommended or standard recommended concentration value for the end-expiratory concentration is calculated based on the measured N2O value and patient demographic data (such as patient age and weight). Then, at step 116, the current setting (including the end-expiratory concentration and / or standard concentration value) is compared with the recommended concentration or standard recommended concentration value to determine if there is a difference between the current vaporizer setting and the recommended value. If the difference exceeds a threshold difference, a suggested alert is displayed at step 118 to ensure that the vaporizer setting changes to improve anesthesia administration to the patient. For example, the suggested alert may be presented on the user interface 30, 30a of the electronic vaporizer 12.

[0042] Then, at step 120, user input is received, such as via user interface 30, 30a, to accept or reject the suggested concentration or a suggested concentration standard value. The vaporizer settings are then maintained or adjusted based on the user input to control the desired end-expiratory concentration of the anesthetic over time for the patient based on the user's acceptance or rejection of the suggestion.

[0043] Figure 6 Another embodiment of a method 100 for controlling an electronic vaporizer system 10 is described. At step 130, the patient's depth of anesthesia is measured, for example, by an anesthesia depth monitor 40, 40a. At step 132, the measured depth of anesthesia is compared with the patient's desired depth of anesthesia. At step 134, the control system determines whether the difference between the desired depth of anesthesia and the measured depth of anesthesia exceeds a threshold.

[0044] At step 131, the end-expiratory concentration of the anesthetic is measured, and at step 133, the measured end-expiratory concentration is compared with the desired end-expiratory concentration. If the difference between the end-expiratory concentration measured at step 135 and the desired end-expiratory concentration exceeds a threshold, then at step 139, a change in the amount of vaporizing agent delivered to the patient is determined based on this difference.

[0045] However, if the measured depth of anesthesia and the desired depth of anesthesia are both within a predefined threshold, and the measured end-tidal concentration and the desired end-tidal concentration are both within a predefined threshold, the current delivery rate of the vaporizing agent is maintained, as indicated in step 136. In other words, if both the patient's depth of anesthesia and the patient's end-tidal concentration are within a predetermined range of the desired values ​​set for the vaporizer, the current delivery rate is maintained. Otherwise, the electronic vaporizer 12 implements a change in anesthetic agent delivery.

[0046] The change in anesthetic delivery volume can be calculated in different ways based on the differences between the measured and expected depth of anesthesia levels, and between the measured and expected end-expiratory concentration (EEC) values. In the depicted example, if the measured EEC is not within the threshold range of the expected EEC, the difference between the measured and expected depth of anesthesia measurements may be due to differences in EEC, especially if the differences in depth of anesthesia values ​​and EEC values ​​are consistent. This example assumes such consistency. If the difference between the measured and expected EEC is greater than the threshold, the system adjusts the vaporization agent delivered to the patient at step 139 based on the difference to make the measured EEC consistent with the expected EEC. In another embodiment, if the system fails to achieve the set target EEC, i.e., the measured EEC is lower than the expected EEC, the system can generate an alarm indicating that the system has failed to achieve its programmed target, possibly signaling a system malfunction, leakage in the respiratory system, etc.

[0047] This may also reduce the difference between the measured depth of anesthesia and the desired depth of anesthesia. However, if at step 138 the difference between the measured end-expiratory concentration and the desired end-expiratory concentration is less than a threshold, meaning that the measured end-expiratory concentration and the desired end-expiratory concentration are within a predefined threshold range, steps can be taken to adjust or recalculate the desired end-expiratory concentration so that the patient's depth of anesthesia reaches the desired depth.

[0048] At step 140, a new desired end-tidal concentration is determined based on the difference between the measured depth of anesthesia and the desired depth of anesthesia. Then, at step 142, a change in the amount of vaporizing reagent is determined based on the new desired end-tidal concentration. The vaporizer unit 14 is then controlled accordingly to deliver a specific amount of vaporizing reagent.

[0049] As used herein, the term controller or module may refer to, be part of, or include: application-specific integrated circuits (ASICs); electronic circuits; combinational logic circuits; field-programmable gate arrays (FPGAs); processors (shared processors, dedicated processors, or group processors) that execute code; or other suitable components that provide the aforementioned functionality; or combinations of some or all of the foregoing, such as in a system-on-a-chip. The term controller or module may include memory (shared memory, dedicated memory, or group memory) storing code executed by a processor. As used herein, the term code may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, and / or objects. The term shared, as used above, means that some or all of the code from multiple modules can be executed using a single (shared) processor. Additionally, some or all of the code executed by multiple different processors may be stored in a single (shared) memory. The term group, as used above, means that a group of processors can be used to execute some or all of the code comprising a portion of a single controller or module. Similarly, a group of memories can be used to store some or all of the code comprising a single controller or module.

[0050] This written description uses examples to disclose the invention, including the best mode, and also enables those skilled in the art to perform and use the invention. Certain terms are used for the purpose of brevity, clarity, and ease of understanding. Unnecessary limitations should not be inferred from this description beyond the requirements of the prior art, as such terms are used for descriptive purposes only and are intended to be understood broadly. The patent scope of this invention is defined by the claims and may include other examples that would occur to those skilled in the art. These other examples are intended to be within the scope of the claims if they have features or structural elements that are not different from the literal language of the claims, or if they include equivalent features or structural elements that are not substantially different from the literal language of the claims.

Claims

1. An electronic vaporizer system, the electronic vaporizer system comprising: An anesthetic storage tank, wherein the anesthetic storage tank contains anesthetic; A vaporizer unit that vaporizes the anesthetic agent from the reservoir and delivers the anesthetic agent into the patient's breathing circuit; A gas sensor configured to measure the end-tidal concentration of the anesthetic in the patient's exhaled breath; The control system is configured to: The measured end-tidal concentration of the anesthetic agent received; The measured end-expiratory concentration is compared with the desired end-expiratory concentration that the patient wants to maintain; and Based on the comparison, the vaporizer unit is automatically controlled to deliver a specific amount of anesthetic into the patient's breathing circuit. The control system is further configured to: Receive one or more standard concentration values; and The desired end-tidal concentration is automatically adjusted based on the stated concentration norm.

2. The system of claim 1, further comprising at least one ventilation gas sensor configured to sense the flow rate of inhaled gas in the breathing circuit; The control system is further configured to control the vaporizer unit based on the flow rate of the inhaled gas to deliver the amount of anesthetic into the patient's breathing circuit.

3. The system of claim 1, wherein the control system is configured to determine a change in the amount of the anesthetic to be delivered to the patient's breathing circuit based on the difference between the measured end-expiratory concentration and the desired end-expiratory concentration, and to control the vaporizer unit to achieve the change.

4. The system of claim 1, further comprising an anesthesia depth monitor configured to measure the anesthesia depth of the patient; The control system is further configured to: Determine that the difference between the measured depth of anesthesia and the desired depth of anesthesia exceeds a threshold; and The new desired end-tidal concentration is determined based on the difference between the measured depth of anesthesia and the desired depth of anesthesia.

5. The system of claim 1, wherein the desired end-tidal concentration is received from a clinician via a user interface on the vaporizer system.

6. The system of claim 1, wherein the storage tank and the vaporizer unit are housed together in a housing.

7. The system of claim 6, further comprising a touchscreen on the housing, the touchscreen being configured to receive control input for the vaporizer system and display at least one of the measured end-expiratory concentration, the desired end-expiratory concentration, and the difference between the measured end-expiratory concentration and the desired end-expiratory concentration.

8. The system of claim 6, wherein the housing is configured to be removably attached to a ventilator system configured to ventilate the patient.

9. The system of claim 6, further comprising an anesthesia depth monitor configured to connect to a sensor and measure the anesthesia depth of the patient, wherein the anesthesia depth monitor is housed within the housing.

10. The system of claim 6, further comprising a dial on the housing movable to control the mode of the vaporizer system between a manual mode and an automatic mode, wherein in the manual mode a clinician manually controls the amount of anesthetic delivered to the patient's breathing circuit, and in the automatic mode the control system automatically controls the vaporizer unit to deliver the amount of anesthetic to the patient's breathing circuit.

11. The system of claim 1, wherein the control system is further configured to: The recommended concentration is calculated based on patient demographic data, and the desired end-tidal concentration is adjusted based on the recommended concentration.

12. An apparatus for controlling a vaporizer system, the vaporizer system being configured to vaporize an anesthetic agent and deliver the anesthetic agent to a patient's breathing circuit, the apparatus comprising: monitor; as well as A processor configured with instructions in non-transitory memory, which, when executed, cause the processor to: Measure the end-tidal concentration of the anesthetic in the patient's exhaled breath; Compare the measured end-tidal concentration with the end-tidal concentration that the patient wants to maintain; as well as The comparative automatic control vaporizer unit delivers a specific amount of anesthetic into the patient's breathing circuit to maintain the measured end-expiratory concentration within a predetermined range of desired end-expiratory concentration. The instructions, when executed, further cause the processor to: Receive one or more standard concentration values ​​selected by the clinician; and The desired end-tidal concentration is automatically adjusted based on the selected concentration norm value.

13. The apparatus of claim 12, wherein the instructions, when executed, further cause the processor to: Sensing the flow rate of inhaled gas in the breathing circuit; and The vaporizer unit is further controlled based on the flow rate of the inhaled gas to deliver the amount of anesthetic into the patient's breathing circuit.

14. The apparatus of claim 12, wherein the instructions, when executed, further cause the processor to: The amount of anesthetic to be delivered to the patient's breathing circuit is determined based on the difference between the measured end-expiratory concentration and the desired end-expiratory concentration, and the vaporizer unit is controlled to achieve the change.

15. The apparatus of claim 12, wherein the instructions, when executed, further cause the processor to: Measure the depth of anesthesia in the patient; Determine that the difference between the measured depth of anesthesia and the desired depth of anesthesia exceeds a threshold; and The new desired end-tidal concentration is determined based on the difference between the measured depth of anesthesia and the desired depth of anesthesia.

16. The apparatus of claim 12, wherein the instructions, when executed, further cause the processor to: Before the vaporizer unit automatically delivers the amount of anesthetic into the patient's breathing circuit, the dial position of the dial on the vaporizer system associated with the automatic mode is sensed.

17. The apparatus of claim 12, wherein the instructions, when executed, further cause the processor to: Sensing the N2O concentration of the inhaled gas in the breathing circuit; and The desired end-tidal concentration is determined based on the N2O concentration.

18. The apparatus of claim 12, wherein the instructions, when executed, further cause the processor to: Receive the recommended concentration calculated based on the patient's patient demographic data from the network computer; Compare the desired end-tidal concentration with the recommended concentration; Based on the comparison, recommendations for concentration changes are determined; as well as The concentration change recommendation is displayed on the display of the vaporizer system.

19. The apparatus of claim 18, wherein the instructions, when executed, further cause the processor to: The desired end-tidal concentration is automatically adjusted based on the suggested concentration.

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