JP2007097931A - Inhalation anesthetic apparatus, method for changing flow rate of inhaled gas, and method for changing concentration of anesthetic in inhaled gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inhalation anesthetic apparatus capable of feeding a large amount of inhaled gas such as an anesthetic gas containing an anesthetic or the air if necessary, quickly causing the induction of or awakening from the anesthesia, and modifying the flow rate of the inhaled gas or the concentration of the anesthetic smoothly. <P>SOLUTION: This inhalation anesthetic apparatus has an inhalation pathway 3 and an exhalation pathway 4 at its trachea joint 2. The inhalation pathway 3 is provided with a pump 5 for feeding gas, a mass flow controller 6 for adjusting the gas flow rate, and an anesthetic supply means 7 for feeding an anesthetic to the gas, while the exhalation pathway 4 is provided with an respiratory gas valve 10 for switching the inhalation action with the exhalation action, or vice versa, at the trachea joint 2. The inhalation pathway 3 is provided with a bypass circuit 13 capable of feeding the gas without passing it through the mass flow controller 6, and a diverging path 16 on the downstream side from the anesthetic supply means 7 via a switching valve 9. The diverging path 16 is provided with a large-amount gas feed means 17 which can feed the gas in large quantity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inhalation anesthesia apparatus for inhaling an inhalation gas containing an anesthetic into a person or an animal, a method for changing the flow rate of the inhalation gas when the inhalation anesthesia apparatus is used, and an anesthetic for the inhalation gas The present invention relates to a density changing method.

  Conventionally, as an inhalation anesthesia device mainly used when performing anesthesia for humans, an anesthesia machine that supplies anesthetic gas by mixing volatile anesthetics into carrier gas such as oxygen gas, laughing gas and air It is known that an anesthesia gas supplied from the anesthesia machine body is mixed with the circulation air after absorbing and removing carbon dioxide gas from the exhalation of the patient and sent to the patient as an inhalation gas. Yes.

  On the other hand, when anesthesia is performed on small animals such as mice, the above-mentioned inhalation anesthesia apparatus for humans is applied as it is because the amount of gas to be inhaled during breathing is small and the number of breaths is large compared to humans. It was difficult. For this reason, conventionally, a mouse or the like is housed in a sealed box, and anesthesia gas is supplied into the box to introduce anesthesia. Then, the mouse is taken out of the box to perform a procedure such as surgery. When anesthesia is awakened, the anesthetic is immersed in gauze and applied near the nose, or anesthetic gas is supplied near the nose by a mask to maintain anesthesia. In addition, when artificial respiration is necessary, it has been connected to a respirator adapted to the amount of inhaled gas such as a mouse.

As a ventilator for small animals such as mice, a pressure regulating type that delivers a certain volume of inspiratory gas and the pressure in the trachea were measured, and this pressure was maintained at a preset pressure. Although there are pressure regulation types, these conventional ventilators cannot be used while performing inhalation anesthesia.
Therefore, in Patent Document 1, it is assumed that artificial respiration can be performed while performing inhalation anesthesia, a trachea connection part connected to a trachea of a small animal, an intake path for supplying intake gas to the trachea connection part, and a trachea There has been proposed a ventilator for a volatile anesthetic solution provided on a ventilator for small animals provided with an exhalation path through which exhalation gas discharged from a connecting portion passes.
JP 2005-230509 A

By the way, in the artificial respiration apparatus described in Patent Document 1, a mass flow controller for accurately adjusting the gas flow rate in accordance with the breathing of an animal or the like connected to the trachea connection portion is disposed in the inspiratory path. In order to ensure the accuracy in the flow rate, a large amount of anesthetic gas could not be circulated through the intake passage, and it took a lot of time to introduce anesthesia.
In addition, when awakening from the state of anesthesia, there is a problem that even if the supply of anesthetic is stopped, the concentration of the anesthetic in the inspiratory gas does not decrease immediately, and it takes time to wake up. .

  In addition, when changing the flow rate of the inspiratory gas, it is necessary to change the supply amount of the anesthetic, but usually it takes longer to adjust the supply amount of the anesthetic compared to the flow rate adjustment. Even if the amount of supply is adjusted, the concentration of the anesthetic in the inhalation gas cannot be changed immediately. For this reason, when the flow rate of the intake gas is decreased, the anesthetic concentration in the intake gas temporarily becomes excessively high. Conversely, when the flow rate of the intake gas is increased, the flow rate is temporarily increased. In addition, there is a problem that the anesthetic concentration in the inhalation gas becomes excessively low.

  In addition, when changing the concentration of the anesthetic in the inspiratory gas, even if the supply amount of the anesthetic is adjusted, the inspiratory gas that is the concentration of the anesthetic before the change is stored inside the intake passage, etc. There is a problem that the anesthetic concentration does not change immediately, and it takes a considerable time to reach the changed anesthetic concentration.

  The present invention has been made in view of the above circumstances, and an anesthetic gas containing an anesthetic or an inhalation gas such as air is supplied in large quantities as necessary to introduce anesthesia or awaken from anesthesia. An inhalation anesthesia device that can change the inspiratory gas flow rate and anesthetic concentration smoothly, a method for changing the inspiratory gas flow rate using the inhalation anesthesia device, and the anesthetic concentration of the inspiratory gas The purpose is to provide a change method.

  In order to achieve the above object, an inhalation anesthesia apparatus according to the present invention has a trachea connection part connected to a trachea, an intake path for supplying intake gas to the trachea connection part, and exhausted from the trachea connection part An exhalation path through which exhaled gas is circulated, and in the inhalation path, a pump for supplying gas, a mass flow controller for adjusting the flow rate of the gas, and an anesthetic supply means for supplying an anesthetic to the gas The exhalation path is provided with an artificial respiration function provided with an exhalation valve for switching between an inhalation operation and an exhalation operation at the trachea connection portion, and the mass flow controller is allowed to pass through the inhalation path. A bypass circuit capable of supplying the gas without being provided, and a branch path is formed on the downstream side of the anesthetic supply means via a switching valve, so that a large amount of gas can be supplied to the branch path Is characterized in that scan supply means is provided.

  In the inhalation anesthesia apparatus having this configuration, since a bypass circuit that can supply gas without passing through the mass flow controller is provided, a large flow rate gas exceeding the maximum flow rate of the mass flow controller can be supplied. In addition, since a large flow of gas does not pass through the mass flow controller, the mass flow controller can be used in a range that matches the amount of gas that is inhaled when the animal connected to the trachea connection breathes. It can be adjusted with high accuracy.

In addition, a branch passage is formed on the downstream side of the anesthetic supply means via a switching valve, and the branch passage is provided with a large amount gas supply means capable of supplying a large amount of gas. It can supply to an animal etc. from this mass gas supply means. For example, when an anesthesia room is provided as the mass gas supply means, anesthesia can be quickly introduced by accommodating a small animal such as a mouse in the anesthesia room and supplying a large amount of anesthesia gas.
On the other hand, when awakening an animal or the like placed in the trachea connection portion from anesthesia, a large amount of air or the like is circulated in the intake passage using the bypass circuit, so that it remains inside the intake passage or the like. Since the gas mixed with the anesthetic agent can be quickly replaced with air or the like, and the air or the like can be supplied to the anesthesia room, the animal or the like housed in the anesthesia room can be awakened again from anesthesia in a short time.

  Further, the anesthetic supply means is composed of a vaporizing chamber for vaporizing the volatile anesthetic liquid, a drug delivery tube connected to the vaporizing chamber, and an infusion pump for supplying the volatile anesthetic liquid. The anesthetic concentration in the inspiratory gas can be adjusted by adjusting the injection amount of the anesthetic liquid into the vaporizing chamber with an infusion pump.

  Here, it is preferable to employ a syringe pump as the infusion pump. Some volatile anesthetic liquids are corrosive, and the durability of the parts that come in direct contact with the anesthetic liquid becomes a problem, but if it is a syringe pump, the syringe part in which the anesthetic liquid is stored can be disposable. Therefore, it is not necessary to consider long-term durability. Moreover, since the quality controlled syringe pump can be used, the anesthetic solution can be injected with high accuracy.

  In addition, an anesthetic liquid is detected by the liquid detection means before the anesthetic supply means is operated by disposing a liquid detection means for confirming the presence or absence of liquid in the medicine delivery tube connected to the vaporization chamber. The drug solution can be sent to the vaporizing chamber side in a short time until the drug delivery tube is filled with the anesthetic solution. Therefore, when the anesthetic supply means is operated, the anesthetic liquid is immediately supplied into the vaporizing chamber, and the anesthetic can be supplied quickly into the inspiratory gas.

  Further, an introduction path for introducing the exhaled gas discharged from the exhalation valve into the branch path is formed, and an anesthetic concentration in the gas is provided downstream of a connection portion between the introduction path and the branch path. When a large amount of gas is supplied from a large amount of gas supply means via a branch path by arranging a gas concentration sensor for measuring the concentration of anesthetic in the gas, this gas concentration sensor can measure When anesthesia is performed while performing artificial respiration through the trachea connection part, the anesthetic concentration in the exhalation gas from the trachea connection part can be measured by this gas concentration sensor.

  By measuring the concentration of the anesthetic agent of the breath gas in this way, the state of the animal or the like connected to the trachea connection portion can be confirmed, and information necessary for confirming the state of anesthesia can be obtained. Furthermore, when an infrared absorption type gas concentration sensor is used, the carbon dioxide concentration can be measured, so the carbon dioxide concentration in the exhaled gas is monitored to check the ventilation status by the ventilator can do.

  When reducing the set flow rate of the inhalation gas using the inhalation anesthesia apparatus having the above-described configuration, the bypass use time prepared in advance is selected according to the flow rate difference between the pre-change flow rate and the post-change flow rate, and the bypass It is preferable to change the anesthetic supply amount according to the changed flow rate after a gas having an anesthetic concentration lower than the set concentration is circulated through the bypass use time using a circuit. By reducing the set flow rate in this manner, it is possible to prevent the anesthetic concentration from becoming temporarily higher than the set concentration when the gas flow rate is reduced.

  On the other hand, when the set flow rate of the inhalation gas is increased using the inhalation anesthesia apparatus, a bypass use time prepared in advance is selected according to the flow rate difference between the pre-change flow rate and the post-change flow rate, and the bypass It is preferable to change the anesthetic supply amount according to the changed flow rate after circulating a gas having an anesthetic concentration higher than the set concentration using the circuit after the bypass usage time. By increasing the set flow rate in this way, it is possible to prevent the anesthetic concentration from becoming temporarily lower than the set concentration when the gas flow rate is increased.

  Moreover, when reducing the anesthetic concentration in the inspiratory gas using the above inhalation anesthesia apparatus, according to the concentration difference between the concentration before change and the concentration after change, select a bypass use time prepared in advance, It is preferable to change the anesthetic supply amount according to the changed concentration after the gas having an anesthetic concentration lower than the changed concentration is circulated for the bypass use time using the bypass circuit. By changing the concentration of the anesthetic agent in this way, the concentration of the anesthetic agent in the gas can be adjusted after replacing the gas stored inside the intake passage, etc., so the anesthetic concentration can be reduced in a short time Can do.

  On the other hand, when increasing the anesthetic concentration in the inspiratory gas using the above inhalation anesthesia device, according to the concentration difference between the concentration before change and the concentration after change, select a bypass use time prepared in advance, It is preferable that the anesthetic concentration gas higher than the changed concentration is distributed to the anesthetic supply amount according to the changed concentration after the bypass usage time is circulated using the bypass circuit. By changing the concentration of the anesthetic agent in this way, the concentration of the anesthetic agent in the gas can be adjusted after replacing the gas stored inside the intake passage, etc., so that the anesthetic concentration can be increased in a short time Can do.

  According to the present invention, an anesthetic gas containing an anesthetic or an inhalation gas such as air can be supplied in a large amount as needed to quickly introduce anesthesia or awaken from anesthesia, It is possible to provide an inhalation anesthesia apparatus capable of smoothly changing a flow rate and an anesthetic concentration, a method for changing an inhalation gas flow rate and an inhalation gas anesthetic concentration changing method using the inhalation anesthesia apparatus.

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a circuit configuration diagram of an inhalation anesthesia apparatus according to an embodiment of the present invention.
The inhalation anesthesia apparatus 1 is optimal for performing anesthesia on a small animal such as a mouse, and includes a trachea connection portion 2 connected to the trachea of the small animal, and an intake path for supplying intake gas to the trachea connection portion 2 3 and an exhalation path 4 through which the exhaled gas discharged from the trachea connecting portion 2 flows.

At one end of the intake path 3, a pump unit 5 that supplies air into the intake path 3 is arranged, and the pump unit 5 supplies air to the trachea connection unit 2 side (downstream side) from the pump unit 5. A thermal mass flow controller 6 that adjusts the flow rate of air is disposed, and is configured so that a constant flow rate of air can be supplied into the intake passage 3.
To the trachea connection part 2 side (downstream side) from the thermal mass flow controller 6, an anesthetic supply means 7 for mixing an anesthetic into the supplied air and an excess pressure in the intake passage 3 are released. A relief valve 8 and a switching valve 9 are sequentially arranged, and the other end side of the intake passage 3 is connected to the trachea connection portion 2.

  On the other hand, one end of the expiratory path 4 is connected to the trachea connecting portion 2, and an expiratory valve 10 is provided on the other end side. In addition, a pressure gauge 11 for measuring the pressure in the expiration path 4 is disposed in the expiration path 4, and the pressure gauge 11 is closed for use when performing zero calibration of the pressure gauge 11. A valve 12 is provided.

  The intake passage 3 is provided with a bypass circuit 13 for circulating air without passing through the thermal mass flow controller 6. The bypass circuit 13 includes a flow path switching valve 14 disposed between the pump unit 5 and the thermal mass flow controller 6, one end connected to the flow path switching valve 14, and the other end connected to the thermal mass flow controller 6 and the anesthetic. The bypass means 15 is connected to the supply means 7.

  The switching valve 9 disposed on the trachea connection part 2 side (downstream side) with respect to the anesthetic supply means 7 is provided with an anesthesia chamber 17 capable of accommodating a small animal such as a mouse via a branch path 16. An adsorption column 18 equipped with activated carbon for adsorbing the exhausted anesthetic gas is disposed in the exhaust part of the anesthesia chamber 17. In addition, it is preferable that this anesthesia room 17 is comprised with transparent resin so that the appearances of the mouse | mouth etc. which were accommodated in the inside can be visually observed.

  Further, an introduction path 19 is connected to the exhaust side of the exhalation valve 10, and one end of the introduction path 19 is connected to the branch path 16. A gas concentration sensor 20 for measuring the anesthetic concentration in the gas is disposed between the connecting portion of the introduction path 19 and the branch path 16 and the anesthetic chamber 17. This gas concentration sensor 20 is of an infrared absorption type, and can measure carbon dioxide concentration in addition to anesthetic gas.

  Next, the anesthetic supply means 7 will be described. The anesthetic supply means 7 in the present embodiment vaporizes a volatile anesthetic solution such as sevoflurane and mixes it in the air. The vaporizing chamber 21 in which the air supplied from the pump unit 5 is circulated, and this vaporization are provided. It consists of a drug delivery tube 22 for supplying an anesthetic solution to the chamber 21 and an injection pump 23 for injecting the anesthetic solution. Here, in this embodiment, a syringe pump is employed as the infusion pump 23, and the anesthetic liquid stored in the syringe is injected and stored by converting the rotational motion of the pulse motor into a linear motion and pushing it. When the anesthetic solution was exhausted, the syringe was changed to another syringe. Further, an ultrasonic sensor 24 is disposed in the medicine delivery tube 22 in order to detect the presence or absence of liquid.

  An example of the vaporization chamber 21 is shown in FIGS. The vaporizing chamber 21 is a container having a substantially cylindrical shape, and a lid portion 21a is formed on the upper portion. An air intake port 21b, an exhaust port 21c, and an anesthetic liquid supply port 21d are formed in the lid portion 21a. Yes. The anesthetic liquid supply port 21 d is provided with a needle-like discharge part 21 e, and the tip of the discharge part 21 e is disposed so as to substantially contact the bottom surface of the vaporizing chamber 21.

  Next, the operation of the inhalation anesthesia apparatus 1 having this configuration will be described. Air is sent into the intake path 3 by the pump unit 5. Here, air is introduced into the bypass path 15 by the flow path switching valve 14, and air is taken into the vaporizing chamber 21 of the anesthetic supply means 7 without passing through the thermal mass flow controller 6. Sevoflurane as a volatile anesthetic solution is injected into the vaporizing chamber 21 from a syringe pump, vaporized, and an anesthetic gas in which an anesthetic is mixed with air is sent downstream. This anesthetic gas is introduced into the branch path 16 by the switching valve 9 and supplied into the anesthesia chamber 17. The mouse is housed in the anesthesia room 17 and anesthesia is introduced into the mouse.

  After anesthesia is introduced in the anesthesia room 17 in this way, the anesthesia gas is supplied out of the anesthesia room 17 by using a mask to maintain the anesthesia, or the trachea connection part 2 is connected to the trachea of the mouse. Connected to perform artificial respiration and continuously inhale anesthetic gas. In this case, the air sent from the pump unit 5 is introduced to the thermal mass flow controller 6 side by the flow path switching valve 14, and the flow rate of the air is changed to the inhaled gas amount at the time of breathing of the mouse by the thermal mass flow controller 6. After adjustment, the air is supplied to the vaporizing chamber 21 of the anesthetic supply means 7. The anesthetic gas mixed with the anesthetic in the vaporizing chamber 21 is sent to the trachea connection portion 2 side and the expiration route 4 side by the switching valve 9.

  Here, by closing the exhalation valve 10 provided on the other end side of the exhalation path 4, the pressure in the exhalation path 4, the inhalation path 3, and the trachea connection part 2 is increased, and the mouse is passed through the trachea connection part 2. Anesthesia gas will be sent to. On the other hand, when the exhalation valve 10 is opened, the lungs of the mouse are elastically restored, and the exhalation is exhausted through the trachea connection portion 2. Thus, the artificial respiration of the mouse can be performed by opening and closing the exhalation valve 10.

  The opening / closing operation of the expiratory valve 10 is performed based on the set number of breaths and the ratio of inspiratory time to expiratory time, and the inspiratory amount is regulated by the flow rate by the thermal mass flow controller 6 (capacity regulating method), or the pressure gauge 11 The pressure is regulated by the pressure in the exhalation path 4 (pressure regulation method). In the capacity regulation method, the tidal volume is guaranteed, but uneven ventilation is likely to occur. On the other hand, in the pressure regulation type, although the uneven ventilation is small, the tidal volume is not stable. In this embodiment, since the thermal mass flow controller 6 and the pressure gauge 11 are provided, it is configured to be able to cope with either the capacity defining formula or the pressure defining formula, and can be appropriately selected according to the purpose of use.

  When the mouse is awakened from anesthesia, fresh air that is not mixed with an anesthetic may be supplied to the mouse. First, the injection pump 23 is stopped, and the injection of the anesthetic liquid into the vaporizing chamber 21 is stopped. Then, air is introduced into the bypass path 15 by the flow path switching valve 14, and a large amount of air is sent to the intake path 3 without passing through the thermal mass flow controller 6 to enter the vaporization chamber 21, the intake path 3, and the like. The remaining anesthetic gas is replaced with air at once. Since air can be supplied to the anesthesia room 17 after replacement with air in this manner, the mouse housed in the anesthesia room 17 can be awakened from anesthesia in a short time.

Next, a method for changing the flow rate of the anesthetic gas supplied to the intake passage 3 and the method for changing the anesthetic concentration in the inhalation anesthesia apparatus 1 of the present embodiment will be described.
First, when the flow rate of the anesthetic gas supplied to the intake path 3 is decreased, a bypass use time prepared in advance is selected according to the flow rate difference between the pre-change flow rate and the post-change flow rate. Here, the bypass use time is calculated so that the anesthetic concentration of the gas in the vaporizing chamber 21 and the intake passage 3 becomes the set concentration at the changed flow rate. A large amount of air is taken into the vaporization chamber 21 via the bypass circuit 13, and an anesthetic gas having an anesthetic concentration lower than the set concentration is circulated to the intake passage 3 to replace the gas stored in the intake passage 3. After the flow, the flow path switching valve 14 is switched to the thermal mass flow controller 6 side to reduce the air flow rate and adjust the injection amount of the anesthetic from the injection pump 23.

  On the other hand, when increasing the flow rate of the anesthetic gas supplied to the intake path 3, a bypass use time prepared in advance is selected according to the flow rate difference between the pre-change flow rate and the post-change flow rate, via the bypass circuit 13. A large amount of air is taken into the vaporizing chamber 21, an anesthetic gas with an anesthetic concentration higher than the set concentration is circulated to the intake passage 3, and the gas stored in the intake passage 3 is replaced. The path switching valve 14 is switched to the thermal mass flow controller 6 side to increase the air flow rate and adjust the amount of anesthetic injected from the infusion pump 23.

  Further, when the anesthetic concentration of the anesthetic gas supplied to the intake path 3 is decreased, a bypass use time prepared in advance is selected according to the concentration difference between the concentration before change and the concentration after change. Here, the bypass use time is calculated so that the anesthetic concentration of the gas in the vaporization chamber 21 and the intake passage 3 becomes the changed concentration. A large amount of air is taken into the vaporization chamber 21 via the bypass circuit 13 and an anesthetic gas having an anesthetic concentration lower than the changed concentration is circulated to the inspiratory path 3, and then an anesthetic liquid injection amount that matches the changed concentration The infusion pump 23 is adjusted so that

  On the other hand, when the anesthetic concentration of the anesthetic gas supplied to the intake path 3 is increased, a bypass use time prepared in advance is selected according to the concentration difference between the concentration before change and the concentration after change, and the bypass circuit After a large amount of air is taken into the vaporization chamber 21 via 13 and an anesthetic gas having an anesthetic concentration higher than the changed concentration is circulated to the inspiratory passage 3, the anesthetic liquid is injected in accordance with the changed concentration. Thus, the infusion pump 23 is adjusted.

  In the inhalation anesthesia apparatus 1 according to the present embodiment, the bypass circuit 13 that can supply air without passing through the thermal mass flow controller 6 is provided, so that a large flow rate air exceeding the maximum flow rate of the thermal mass flow controller 6 is vaporized. It can be taken into the chamber 21. Further, a branch path 16 is formed on the downstream side of the anesthetic supply means 7 via the switching valve 9, and an anesthesia room 17 that can accommodate a mouse is provided in the branch path 16. Anesthesia can be quickly introduced to the mouse by supplying a large amount of anesthetic gas in which an anesthetic is mixed into the supplied air to the anesthesia room 17.

  When the mouse is awakened from anesthesia, a large amount of air is introduced into the intake passage 3 through the bypass circuit 13 so that the anesthetic gas remaining in the intake passage 3 and the vaporizing chamber 21 can be replaced with air at once. Therefore, fresh air can be sent to the anesthesia room 17 in a short time, and the mouse accommodated in the anesthesia room 17 can be awakened from anesthesia in a short time.

The anesthetic supply means 7 includes a vaporizing chamber 21 for vaporizing a volatile anesthetic liquid, a medicine feeding tube 22 connected to the vaporizing chamber 21, and an infusion pump 23 for supplying a volatile anesthetic liquid. And since the syringe pump is employ | adopted as this infusion pump 23, the injection amount of an anesthetic liquid can be adjusted by adjusting the moving speed of the piston of a syringe pump. In addition, since the syringe pump can be disposable after using the anesthetic solution stored in the syringe, it is not necessary to consider long-term durability against the anesthetic solution. Moreover, since the quality-controlled syringe pump is used as a product, the anesthetic solution can be injected with high accuracy.
The vaporizing chamber 21 is preferably provided with a heater in order to prevent a temperature drop due to the heat of vaporization of the anesthetic solution.

  In addition, since the ultrasonic sensor 24 is arranged as a liquid detection means for confirming the presence or absence of liquid in the medicine delivery tube 22 connected to the vaporizing chamber 21, before the anesthetic supply means 7 is operated, the infusion pump 23 can be used to inject the anesthetic solution in a short time until the ultrasonic sensor 24 detects the anesthetic solution. Therefore, when the anesthetic supply means 7 is operated, the anesthetic solution is immediately supplied into the vaporizing chamber 21, and the anesthetic can be supplied quickly into the air.

  In addition, an introduction path 19 for introducing the exhaled gas discharged from the exhalation valve 10 into the branch path 16 is formed, and an infrared absorption type gas concentration sensor 20 is disposed downstream of the connection portion between the introduction path 19 and the branch path 16. Therefore, when a large amount of anesthetic gas is supplied into the anesthesia room 17 via the branch path 16, the gas concentration sensor 20 can measure the anesthetic concentration in the gas and connect the trachea. When anesthesia is performed while performing artificial respiration through the unit 2, the concentration of the anesthetic in the exhalation gas from the trachea connection unit 2 can be measured by the gas concentration sensor 20.

  Thus, by measuring the concentration of the anesthetic agent of exhaled gas, the internal state of the mouse connected to the trachea connection unit 2 can be confirmed, and information necessary for confirming the state of anesthesia can be obtained. Further, since an infrared absorption type gas concentration sensor 20 is used, the carbon dioxide concentration can be measured, and the state of ventilation by the ventilator is confirmed by monitoring the concentration of carbon dioxide in the expiration gas. You can also.

  Further, when the inhalation anesthesia apparatus 1 is used to reduce the set flow rate of the anesthetic gas, after the inside of the intake passage 3 is replaced with an anesthetic gas having an anesthetic concentration lower than the set concentration, the flow path switching valve 14 is set to thermal. By switching to the mass flow controller 6 side and reducing the air flow rate and adjusting the injection amount of the anesthetic from the infusion pump 23, the anesthetic concentration in the anesthetic gas is temporarily excessively higher than the set concentration. Can be prevented.

  Similarly, when the set flow rate of the anesthetic gas is increased, after the inside of the intake passage 3 is replaced with an anesthetic gas having an anesthetic concentration higher than the set concentration, the flow path switching valve 14 is switched to the thermal mass flow controller 6 side. Since the air flow rate is increased and the amount of the anesthetic injected from the infusion pump 23 is adjusted, the concentration of the anesthetic in the anesthetic gas can be prevented from temporarily becoming lower than the set concentration temporarily.

Further, when the anesthetic concentration in the anesthetic gas is reduced using the inhalation anesthesia apparatus 1, the inhalation path 3 and the inside of the vaporizing chamber 21 are replaced with the changed concentration of the anesthetic gas, and then the anesthetic injection amount is changed. Since it can be adjusted, the anesthetic concentration can be reduced in a short time.
Similarly, when increasing the anesthetic concentration in the anesthetic gas, the anesthetic injection amount can be adjusted after replacing the inside of the intake passage 3 and the vaporizing chamber 21 with the changed concentration of the anesthetic gas. Can be increased in a short time.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
For example, although an inhalation anesthesia apparatus for a mouse has been described, the present invention is not limited to this and may be for other animals and humans. When targeting humans or large animals, it is preferable that a mask be provided instead of the anesthesia room as a mass gas supply means so that a large amount of anesthetic gas can be supplied from the mask.

In addition, although a syringe pump is used as an infusion pump for injecting an anesthetic liquid, the present invention is not limited to this, and a pump having another configuration such as a roller pump or a plunger pump may be used.
Further, although the infrared absorption type gas concentration sensor has been described as being provided, the present invention is not limited to this, and other types of gas concentration sensors such as a crystal oscillation type may be used. There is no need to provide a sensor.

Moreover, although the thermal mass flow controller was used as what adjusts the flow volume of intake gas, it was not limited to this and another mass flow controller may be used.
Furthermore, although the ultrasonic sensor is used as the liquid detection unit, other sensors such as an optical type and a capacitance type may be used, and the liquid detection unit is not necessarily provided.

It is a circuit block diagram of the inhalation anesthesia apparatus which is embodiment of this invention. FIG. 2 is a top view of a vaporization chamber provided in FIG. 1. FIG. 3 is a side view of FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inhalation anesthesia apparatus 2 Trachea connection part 3 Inhalation route 4 Expiration route 5 Pump part (pump)
6 Thermal mass flow controller (mass flow controller)
7 Anesthetic supply means 9 Switching valve 10 Expiratory valve 11 Pressure gauge 13 Bypass circuit 16 Branch 17 Anesthetic room (mass gas supply means)
19 Introducing route 20 Gas concentration sensor 21 Vaporization chamber 22 Drug delivery tube 23 Injection pump 24 Ultrasonic sensor (liquid detection means)

Claims (9)

A trachea connection part connected to the trachea, an inspiratory path for supplying inspiratory gas to the trachea connection part, and an exhalation path through which the exhaled gas discharged from the trachea connection part is provided,
The inhalation path is provided with a pump for supplying gas, a mass flow controller for adjusting the flow rate of the gas, and an anesthetic supply means for supplying an anesthetic to the gas. It has an artificial respiration function with an exhalation valve that switches between inhalation and exhalation in
The intake path is provided with a bypass circuit that can supply the gas without passing through the mass flow controller, and a branch path is formed on the downstream side of the anesthetic supply means via a switching valve. An inhalation anesthesia apparatus comprising a mass gas supply means capable of supplying a large amount of gas.   The anesthetic supply means comprises a vaporizing chamber for vaporizing a volatile anesthetic liquid, a drug delivery tube connected to the vaporizing chamber, and an infusion pump for supplying the volatile anesthetic liquid. The inhalation anesthesia apparatus according to claim 1.   The inhalation anesthesia apparatus according to claim 2, wherein the infusion pump is a syringe pump.   The inhalation anesthesia apparatus according to claim 2 or 3, wherein liquid detection means for confirming the presence or absence of liquid is disposed in the medicine delivery tube connected to the vaporization chamber.   An introduction path for introducing the exhaled gas discharged from the exhalation valve into the branch path is formed, and a gas concentration for measuring an anesthetic concentration in the gas is provided downstream of a connection portion between the introduction path and the branch path. The inhalation anesthesia apparatus according to any one of claims 1 to 4, wherein a sensor is arranged. Using the inhalation anesthesia apparatus according to any one of claims 1 to 5, a method for changing a flow rate of intake gas to reduce a set flow rate of the intake gas,
Depending on the flow rate difference between the pre-change flow rate and the post-change flow rate, select the bypass use time prepared in advance,
A method of changing the flow rate of inhaled gas, wherein a gas having an anesthetic concentration lower than a set concentration using the bypass circuit is changed to an anesthetic supply amount corresponding to the changed flow rate after the bypass usage time has been distributed. . Using the inhalation anesthesia apparatus according to any one of claims 1 to 5, a method for changing a flow rate of intake gas to increase a set flow rate of the intake gas,
Depending on the flow rate difference between the pre-change flow rate and the post-change flow rate, select the bypass use time prepared in advance,
A method for changing the flow rate of intake gas, wherein a gas having an anesthetic concentration higher than a set concentration using the bypass circuit is changed to an anesthetic supply amount corresponding to the changed flow rate after the bypass usage time has been distributed. . An inhalation anesthetic concentration changing method for reducing an anesthetic concentration in the inhalation gas using the inhalation anesthesia apparatus according to any one of claims 1 to 5,
Select the bypass use time prepared in advance according to the concentration difference between the concentration before change and the concentration after change,
Inhalation gas anesthesia, characterized in that an anesthetic concentration lower than the changed concentration using the bypass circuit is changed to an anesthetic supply amount that matches the changed concentration after the bypass usage time has passed. How to change drug concentration An inhalation gas anesthetic concentration changing method for increasing the anesthetic concentration in the inhalation gas using the inhalation anesthesia apparatus according to any one of claims 1 to 5,
Select the bypass use time prepared in advance according to the concentration difference between the concentration before change and the concentration after change,
Inhalation gas anesthesia, characterized in that the anesthetic concentration gas higher than the changed concentration using the bypass circuit is changed to an anesthetic supply amount that matches the changed concentration after the bypass usage time has passed. How to change drug concentration.

Images