JP6567787B1 - Anesthesia machine - Google Patents

Abstract

An anesthesia apparatus capable of accurately delivering a predetermined amount of an anesthetic to a vaporization chamber even if the anesthetic is low in boiling point.
A liquid anesthetic stored in anesthetic tanks 21 and 22 is sent to a vaporizing chamber 5 by a metering pump 4 to vaporize the anesthetic and supply it to a patient. A cooler 3 is provided to cool the anesthetic on the upstream side to the outlet 42 and maintain the anesthetic in the metering pump 4 in a liquid state.
[Selection] Figure 1

Description

  The present invention relates to an anesthetic device for vaporizing a liquid anesthetic and supplying and administering it to a patient.

  In order to control the dose of an anesthetic more appropriately, an anesthesia apparatus that vaporizes a liquid anesthetic and supplies it to a patient has been conventionally used (see Patent Document 1 and Non-Patent Document 1). In this anesthesia apparatus, an anesthetic (anesthetic solution) such as sevoflurane or isoflurane stored in an anesthetic tank is transported and sent to a vaporization chamber by a metering pump. On the other hand, fresh gas in which oxygen, nitrous oxide and air are mixed is supplied to the vaporizing chamber, and the anesthetic and vaporized in the vaporizing chamber are mixed and supplied to the patient.

  Further, in such an anesthesia apparatus, it is necessary to send a small amount of anesthetic (anesthetic solution) to the vaporizing chamber by a predetermined amount with high accuracy. For this reason, the metering pump is driven by a stepping motor, and the rotary motion of the stepping motor is changed to the reciprocating motion and the rotational motion of the plunger of the metering pump, thereby feeding the liquid. That is, a notch is provided at the end of the plunger, and a suction port and a discharge port are provided on the side wall of the cylinder of the metering pump. Then, the plunger moves forward and backward (reciprocating) while rotating, so that the anesthetic is sucked into the cylinder when the notch is opposed to the suction port, and the inside of the cylinder when the notch is opposed to the discharge port. It exhales anesthetics.

Japanese Patent Laid-Open No. 2006-166559

Kazunari Okita; “Easy to use anesthesia machine equipped with electronic anesthetic gas delivery device”, Medical Instrument Vol.69, No.8 (1999)

  By the way, conventionally, anesthetics having a high boiling point (for example, about 50 ° C. or more) such as sevoflurane and isoflurane have been used. For this reason, the anesthetic (anesthetic solution) from the anesthetic tank was not vaporized before being discharged from the metering pump. However, in recent years, anesthetics having a low boiling point such as desflurane (for example, slightly higher than about 20 ° C.) have begun to be used. It will vaporize in the meantime. As a result, it becomes difficult to send a predetermined amount of anesthetic to the vaporization chamber with high accuracy using a metering pump.

  That is, when the anesthetic has a high boiling point and remains liquid, the anesthetic M2 in the notch (dead space) 101a of the plunger 101 shown in FIG. 7 remains in the notch 101a. The anesthetic M1 corresponding to the volume change due to the forward and backward movement of 101 is discharged. However, in the case of an anesthetic having a low boiling point, when the notch 101a faces the discharge port 102a of the cylinder 102, the anesthetic M2 in the notch 101a evaporates and vaporizes, and the volume expands. In some cases, not only the medicine M1 but also part or all of the anesthetic M2 is discharged. That is, there arises a problem that a predetermined amount of anesthetic cannot be accurately delivered to the vaporizing chamber.

  Accordingly, an object of the present invention is to provide an anesthesia apparatus capable of feeding a predetermined amount of anesthetic with high accuracy to a vaporizing chamber even if the anesthetic has a low boiling point.

In order to solve the above-mentioned problem, the invention according to claim 1 is directed to an anesthesia apparatus that sends a liquid anesthetic stored in an anesthetic tank to a vaporizing chamber with a metering pump, vaporizes the anesthetic and supplies it to a patient. a is the said anesthetic cooled upstream to the discharge port of the metering pump, e Bei cooling means for maintaining the anesthetic within the metering pump in the liquid, the metering pump, the suction port and discharge failure A cylinder provided with an outlet, and a plunger provided with a notch portion that moves forward and backward in the axial direction in the cylinder, and the plunger moves forward and backward while rotating around the axis, The pump is configured to suck the anesthetic into the cylinder when the notch faces the suction port, and to discharge the anesthetic within the cylinder when the notch faces the discharge port. Part is said vomiting Rotational speed when passing through the mouth, is set faster than the speed at other rotating, it is characterized.

According to a second aspect of the present invention, in the anesthesia apparatus according to the first aspect , the suction port of the metering pump is connected to the anesthetic agent side via a suction pipe, and the discharge port of the metering pump is connected to the discharge pipe. The internal resistance of the discharge pipe is set larger than the internal resistance of the suction pipe.

According to a third aspect of the present invention, in the anesthesia apparatus according to the first or second aspect, when the anesthetic tank that includes a plurality of the anesthetic tanks and stores a predetermined anesthetic is selected, the cooling is performed. Actuating means.

According to a fourth aspect of the present invention, in the anesthesia apparatus according to the first to third aspects, a heat radiation surface of the cooling means is disposed adjacent to the vaporizing chamber.

  According to invention of Claim 1, even if it is an anesthetic with a low boiling point, the anesthetic in a metering pump is maintained in a liquid state by a cooling means. For this reason, the anesthetic is not vaporized in the metering pump, and a predetermined amount of the anesthetic can be accurately fed to the vaporizing chamber by the metering pump.

Furthermore, since the rotation speed when the notch portion of the plunger passes through the discharge port is set faster than the others, the time during which the notch portion faces the discharge port is shortened. For this reason, it is possible to prevent and suppress the vaporization of the anesthetic agent in the cutout portion while the cutout portion is opposed to the discharge port. It becomes possible to send liquid to the vaporization chamber.

According to the invention of claim 2 , since the in-pipe resistance of the discharge pipe is set larger than the in-pipe resistance of the suction pipe, the resistance and pressure when the anesthetic passes through the discharge pipe is increased, and the anesthetic is excessive. It is possible to prevent or suppress the flow from the discharge pipe to the vaporizing chamber side. As a result, it becomes possible to deliver a predetermined amount of anesthetic to the vaporizing chamber with higher accuracy using a metering pump.

According to the invention of claim 3 , when a predetermined anesthetic, for example, an anesthetic tank in which an anesthetic having a low boiling point is stored, the cooling means is activated. In other words, when an anesthetic other than an anesthetic having a low boiling point, for example, an anesthetic tank storing an anesthetic having a high boiling point, is selected, the cooling means is not activated, and thus the cooling means is wasted. Can be prevented and labor saving can be achieved.

According to the invention of claim 4 , since the heat radiating surface of the cooling means is disposed adjacent to the vaporizing chamber, the heat radiated from the cooling means can be used as a heat source of the vaporizing chamber, thereby saving labor. Is possible.

It is a schematic block diagram which shows the anesthesia apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the state in which the notch part of the plunger of the metering pump of the anesthesia apparatus of FIG. 1 was opposed to the suction inlet. It is sectional drawing which shows the state which the notch part of the plunger of the metering pump of the anesthesia apparatus of FIG. 1 passed the suction inlet. It is sectional drawing which shows the state in which the notch part of the plunger of the metering pump of the anesthesia apparatus of FIG. 1 was opposed to the discharge outlet. It is the figure (a)-(d) which shows the plunger state of the metering pump of the anesthesia device of FIG. 1, the figure (e) which shows the inhalation state of a metering pump, and the time chart (f) of the drive pulse of a stepping motor. . It is a schematic block diagram which shows the control part periphery of the anesthesia apparatus of FIG. It is sectional drawing which shows the state in which the notch part of the plunger of the conventional metering pump was opposed to the discharge outlet.

  The present invention will be described below based on the illustrated embodiments.

  FIGS. 1-6 shows embodiment of this invention, FIG. 1 is a schematic block diagram which shows the anesthesia apparatus 1 which concerns on this embodiment. This anesthesia apparatus 1 is an apparatus which sends the liquid anesthetic stored in the anesthetic tanks 21 and 22 to the vaporizing chamber 5 by the metering pump 4, vaporizes the anesthetic, and supplies it to the patient. The configuration differs from the conventional anesthesia apparatus in that it includes the cooling means 3, and the description of the configuration equivalent to the conventional anesthesia apparatus is omitted and outlined.

  The anesthetic agent tanks 21 and 22 are tanks for storing a liquid anesthetic agent. The first anesthetic agent tank 21 stores an anesthetic agent having a high boiling point such as sevoflurane (for example, about 50 ° C. or more). The second anesthetic tank 22 stores an anesthetic having a low boiling point (for example, about 20 ° C. or more) such as desflurane. These two anesthetic tanks 21 and 22 are connected to the metering pump 4 side via a switching valve (switching valve) 23. Then, as described later, the switching valve 23 is switched so that the anesthetic in the first anesthetic tank 21 or the anesthetic in the second anesthetic tank 22 is sucked by the metering pump 4. ing.

  The metering pump 4 is a valveless plunger pump that sends a predetermined amount of the liquid anesthetic in the anesthetic tanks 21 and 22 to the vaporizing chamber 5, and is inserted into the cylinder 40 and the cylinder 40 as shown in FIG. And a plunger 43. That is, the cylinder 40 has a bottomed cylindrical shape, and a suction port 41 and a discharge port 42 penetrating through the side wall of the cylinder 40 are provided on the bottom side facing each other. The plunger 43 has a cylindrical shape, and is provided with a notch portion 43a having a side surface notched in a D-cut shape on the free end side (the bottom surface side of the cylinder 40).

  Then, as will be described later, when the plunger 43 rotates around the axis and moves back and forth in the axial direction (reciprocating motion), the anesthetic is sucked and discharged repeatedly. That is, as shown in FIG. 2, when the notch 43 a faces the suction port 41 while the plunger 43 is raised, the anesthetic on the side of the anesthetic tanks 21 and 22 is sucked into the cylinder 40. As shown in FIG. 3, after the notch 43 a passes through the suction port 41, as shown in FIG. 4, when the notch 43 a faces the discharge port 42 while the plunger 43 is lowered, the cylinder The anesthetic in 40 is discharged to the vaporizing chamber 5 side. In this way, the plunger 43 having the notch 43a rotates and advances and retreats, so that the plunger 43 opens and closes the suction port 41 and the discharge port 42, so that a valve is unnecessary.

  Such a metering pump 4 is driven by a stepping motor 61 as shown in FIGS. That is, a cylindrical crank 62 is connected to the output shaft of the stepping motor 61, and an upper end portion of the plunger 43 of the metering pump 4 is connected to a bearing 62a provided on the crank 62 via a connecting pin 62b. Here, the shaft center of the output shaft of the stepping motor 61 and the shaft center of the plunger 43 are connected so as to be eccentric (not to be parallel but have a predetermined angle θ). Thus, when the output shaft of the stepping motor 61, that is, the crank 62 rotates in a certain direction, the position and orientation of the connecting pin 62b move, and the plunger 43 rotates and moves forward and backward in the cylinder 40 at the same time. With such an eccentric structure, the stroke length of the plunger 43 in the axial direction changes according to the angle θ formed by the axis of the output shaft of the stepping motor 61 and the axis of the plunger 43. Therefore, the discharge amount of the metering pump 4 can be changed and adjusted by changing the angle θ formed.

  The anesthetic discharged from the metering pump 4 is sent to the vaporizing chamber 5 equipped with a heater and mixed with fresh gas. That is, one end of the discharge pipe 51 is connected to the discharge port 42 of the metering pump 4, the other end of the discharge pipe 51 is connected to the upstream side of the mixing pipe 50 of the vaporizing chamber 5, and further, the upstream end of the mixing pipe 50 Is connected to one end of a fresh gas pipe 52. On the other hand, one end of an anesthetic gas pipe 53 is connected to the downstream end of the mixing pipe 50.

  Then, the anesthetic from the metering pump 4 is sent into the mixing tube 50 and heated by the heater to be vaporized, and fresh gas (for example, oxygen, nitrous oxide, and the like) sent from the other end of the fresh gas tube 52. Mixed with air) to form an anesthetic gas. This anesthetic gas is supplied from the other end of the anesthetic gas pipe 53 to the patient. The anesthetic gas pipe 53 is provided with a concentration measuring device 54 for measuring the anesthetic concentration of the anesthetic gas, and the discharge amount of the metering pump 4 is changed and adjusted based on the measurement result of the concentration measuring device 54. It has become.

  In such a configuration, the cooler 3 that cools the anesthetic at the upstream side LE from the anesthetic tanks 21 and 22 to the discharge port 42 of the metering pump 4 and maintains the anesthetic in the metering pump 4 in a liquid state is provided. Specifically, in this embodiment, the cooler 3 is provided between the switching valve 23 and the suction port 41 of the metering pump 4. In addition, the code | symbol GE of FIG.

  The cooler 3 includes a cooling pipe 30 and a cooling element such as a Peltier element (thermoelectric element). The upstream end of the cooling pipe 30 is connected to the output side of the switching valve 23 by the liquid feeding pipe 24, and the downstream end of the cooling pipe 30 is connected to the suction port 41 of the metering pump 4 by the suction pipe 31. In this way, the suction port 41 of the metering pump 4 is connected to the anesthetic tanks 21 and 22 via the suction pipe 31, the cooler 3 and the liquid feeding pipe 24.

  The anesthetic sent from the liquid feeding pipe 24 into the cooling pipe 30 is cooled by the cooling element and sucked into the metering pump 4 through the suction pipe 31. At this time, more specifically, the anesthetic in the notch 43a remains even if the notch 43a of the plunger 43 faces the discharge port 42 so that the anesthetic in the metering pump 4 is maintained in a liquid state. The cooling temperature and cooling capacity of the cooler 3 are set so as not to vaporize.

  Such a cooler 3 is disposed so that its heat radiation surface is adjacent to the vaporizing chamber 5. That is, the cooler 3 is arranged so that the heat radiating surface that radiates heat from the cooling element of the cooler 3 approaches and is in surface contact with the arrangement surface of the mixing tube 50 of the vaporization chamber 5. Thereby, the heat radiation from the cooler 3 is transferred to the mixing tube 50 so that the anesthetic in the mixing tube 50 is efficiently heated.

  Further, the inner diameter of the discharge pipe 51 is set smaller than the inner diameter of the suction pipe 31. Specifically, the inner diameter of the discharge pipe 51 is set as small as possible within a range in which a predetermined amount of anesthetic flows. For example, the inner diameter of the discharge pipe 51 is set to about 1/6 of the inner diameter of the suction pipe 31. Due to such an inner diameter, the in-pipe resistance of the discharge pipe 51 is set larger than the in-pipe resistance of the suction pipe 31. Here, instead of reducing the inner diameter of the discharge pipe 51, or in addition to reducing the inner diameter, the cross-sectional shape and inner surface roughness of the discharge pipe 51 are changed so that the in-pipe resistance of the discharge pipe 51 is increased. Also good.

  Further, as shown in FIG. 6, a control unit 71 and an operation panel 72 are provided, and the control unit 71 controls the switching valve 23, the cooler 3, the stepping motor 61, and the like based on an input command from the operation panel 72. It is like that. Here, only control different from the conventional one will be described below.

  First, when an anesthetic, that is, anesthetic tanks 21, 22 is selected on the operation panel 72, the switching valve 23 is switched so that the anesthetic tanks 21, 22 communicate with the liquid feeding pipe 24. Further, when a predetermined anesthetic, that is, predetermined anesthetic tanks 21 and 22 is selected, the cooler 3 is activated and activated. Specifically, when the second anesthetic agent tank 22 in which an anesthetic with a low boiling point is stored is selected, the cooler 3 is operated, and the first anesthetic agent tank in which an anesthetic with a high boiling point is stored. If 21 is selected, the cooler 3 is deactivated.

  When a predetermined anesthetic is selected on the operation panel 72, the rotation speed when the notch 43a of the plunger 43 passes through the discharge port 42 is set to be higher than the speed at the other rotation. The stepping motor 61 is controlled (second control is performed). That is, as shown in FIGS. 5 (e) and 5 (f), the notch 43 a is located at the discharge port 42 as compared with the time when the notch 43 a faces the suction port 41 and sucks the anesthetic into the cylinder 40. Oppositely, the drive pulse of the stepping motor 61 is controlled so that the time for discharging the anesthetic in the cylinder 40 is as short as possible. Specifically, the drive pulse width (pulse time interval) is increased during suction, and the drive pulse width is decreased during discharge. Thereby, the time when the notch 43a passes (opposites) the discharge port 42 due to the rotation and reciprocation of the plunger 43 is significantly shorter than the time when the notch 43a passes (opposites) the suction port 41. Become.

  On the other hand, when an anesthetic other than the predetermined anesthetic is selected on the operation panel 72, normal control, that is, first control is performed. Here, the first control is one in which the drive pulse of the stepping motor 61 is always set at a constant interval, and the plunger 43 performs a rotational motion and a reciprocating motion at a constant speed.

  Next, the operation of the anesthesia apparatus 1 having such a configuration and an anesthetic supply method by the anesthesia apparatus 1 will be described. Here, sevoflurane having a boiling point higher than ambient temperature (room temperature) is stored in the first anesthetic tank 21, and desflurane (predetermined anesthetic) having a boiling point lower than room temperature is stored in the second anesthetic tank 22. The case will be mainly described.

  First, when sevoflurane, that is, the first anesthetic tank 21 is selected on the operation panel 72, the switching valve 23 is switched to the first anesthetic tank 21 by the controller 71, and the cooler 3 is deactivated. Subsequently, the stepping motor 61 is driven by the first control, and the plunger 43 of the metering pump 4 performs a rotational motion and a reciprocating motion at a constant speed. As a result, sevoflurane in the first anesthetic tank 21 is sent to the vaporizing chamber 5 and vaporized, and is mixed with fresh gas from the fresh gas pipe 52 to become anesthetic gas. To be supplied and administered to the patient. Here, since sevoflurane has a high boiling point, it remains liquid in the metering pump 4.

  On the other hand, when desflurane, that is, the second anesthetic tank 22 is selected on the operation panel 72, the switching valve 23 is switched to the second anesthetic tank 22 by the control unit 71 and the cooler 3 is activated. Subsequently, the stepping motor 61 is driven by the second control, and the plunger 43 performs a rotational motion and a reciprocating motion so that the cutout portion 43a passes through the discharge port 42 quickly. Thereby, desflurane in the second anesthetic agent tank 22 is cooled by the cooler 3 and maintained in a liquid state in the metering pump 4. Then, desflurane is sent to the vaporizing chamber 5 to be vaporized, mixed with fresh gas from the fresh gas pipe 52 to become anesthetic gas, and this anesthetic gas is supplied to the patient via the anesthetic gas pipe 53.

  Thus, according to this anesthesia apparatus 1 and the anesthesia supply method, even if it is an anesthetic with a low boiling point, the anesthetic in the metering pump 4 is maintained in a liquid state by the cooler 3. For this reason, the anesthetic is not vaporized in the metering pump 4, and a predetermined amount of the anesthetic can be accurately fed to the vaporizing chamber 5 by the metering pump 4.

  Further, since the rotation speed when the notch 43a of the plunger 43 passes through the discharge port 42 is set faster than the others, the time during which the notch 43a faces the discharge port 42 is shortened. For this reason, it can prevent and suppress that the anesthetic in the notch part 43a evaporates while the notch part 43a opposes the discharge port 42, As a result, a predetermined amount of anesthesia with the metering pump 4 It becomes possible to send the medicine to the vaporizing chamber 5 with higher accuracy.

  In addition, since the in-pipe resistance of the discharge pipe 51 is set larger than the in-pipe resistance of the suction pipe 31, the resistance and pressure when the anesthetic passes through the discharge pipe 51 becomes high, and the anesthetic becomes excessive in the discharge pipe 51. It is possible to prevent and suppress the flow from the gas to the vaporizing chamber 5 side. As a result, a predetermined amount of anesthetic can be delivered to the vaporizing chamber 5 with higher accuracy by the metering pump 4.

  On the other hand, the cooler 3 is activated only when a predetermined anesthetic, that is, the second anesthetic tank 22 storing an anesthetic having a low boiling point is selected. In other words, when the first anesthetic tank 21 storing an anesthetic other than the anesthetic having a low boiling point, for example, an anesthetic having a high boiling point, is selected, the cooler 3 is not operated. Therefore, it is possible to save labor by preventing unnecessary operation.

  Furthermore, since the heat radiating surface of the cooler 3 is disposed adjacent to and in surface contact with the vaporizing chamber 5, the heat radiated from the cooler 3 is used as a heat source for the vaporizing chamber 5 (heats the mixing tube 50 by heat radiation). ) And the power consumption of the vaporizing chamber 5 can be saved.

  The embodiment of the present invention has been described in detail above, but the specific configuration is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention, Included in the invention. For example, in the above-described embodiment, a case where two types of anesthetics, that is, two anesthetic tanks 21 and 22 are provided has been described, but three or more anesthetics and anesthetic tanks may be provided.

  Moreover, although the cooler 3 is provided between the switching valve 23 and the suction inlet 41 of the metering pump 4, as long as it is upstream LE, it may be provided anywhere. For example, the cooler 3 may be disposed so as to contact the metering pump 4 and the metering pump 4 may be directly cooled. Further, only in the case of an anesthetic having a low boiling point, the cooler 3 is operated and the stepping motor 61 is driven by the second control. However, the cooler 3 is always operated or the stepping motor is controlled by the second control. 61 may be driven.

DESCRIPTION OF SYMBOLS 1 Anesthesia apparatus 21 1st anesthetic agent tank 22 2nd anesthetic agent tank 23 Switching valve (switching valve)
3 Cooler (cooling means)
30 Cooling Pipe 31 Suction Pipe 4 Metering Pump 40 Cylinder 41 Suction Port 42 Discharge Port 43 Plunger 43a Notch 5 Vaporization Chamber 50 Mixing Pipe 51 Discharge Pipe 54 Concentration Measuring Device 61 Stepping Motor 62 Crank 71 Control Unit 72 Operation Panel LE Upstream GE downstream

Claims (4)

An anesthesia apparatus that sends a liquid anesthetic stored in an anesthetic tank to a vaporizing chamber with a metering pump, vaporizes the anesthetic and supplies it to a patient,
E Bei cooling means wherein cooling the anesthetic upstream to the discharge port of the metering pump, to maintain the anesthetic in the metering pump a liquid,
The metering pump includes a cylinder having a suction port and a discharge port, and a plunger having a notch portion that moves forward and backward in the axial direction in the cylinder, and the plunger rotates around the shaft center. By moving forward and backward, the anesthetic is sucked into the cylinder when the notch faces the suction port, and the anesthetic within the cylinder when the notch faces the discharge port. Is a pump that exhales
The rotational speed when the notch passes through the discharge port is set faster than the speed at the other rotation,
An anesthesia apparatus characterized by that. A suction port of the metering pump is connected to the anesthetic agent side through a suction pipe, and a discharge port of the metering pump is connected to the vaporization chamber side through a discharge pipe;
The internal resistance of the discharge pipe is set larger than the internal resistance of the suction pipe,
The anesthesia apparatus according to claim 1 . A plurality of the anesthetic tanks, and when the anesthetic tank in which a predetermined anesthetic is stored is selected, the cooling means is operated.
The anesthesia apparatus according to claim 1 or 2 . A heat dissipating surface of the cooling means is disposed adjacent to the vaporizing chamber,
The anesthesia apparatus of any one of Claim 1 to 3 characterized by the above-mentioned.

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