System for anesthetizing laboratory animals

• US 6,776,158 B1
• Filed: 07/23/2002
• Issued: 08/17/2004
• Est. Priority Date: 07/26/2001
• Status: Active Grant

• Current Assignee: Euthanex Corporation
• Original Assignee: Euthanex Corporation
• Inventors: Anderson, Leslie B., Agelan, Alexis, Eldon, James
• Primary Examiner(s): Bennett, Henry
• Assistant Examiner(s): PATEL, MITAL B
• Application Number:
  US10/201,848
• Time in Patent Office: 756 Days
• Field of Search: 128/203.12, 128/203.14, 128/203.17, 128/203.26, 128/202.16, 128/203.25, 128/205.26, 128/204.23, 600/21, 600/22, 119/416, 119/417, 119/418, 119/419, 119/420, 119/421
• US Class Current: 128/203.12
• CPC Class Codes: A01K 1/031 Cages for laboratory animals; Cages for measuring metabolism of animals
• CPC Class Codes: A61D 7/04 Devices for anaesthetising animals by gases or vapours; Inhaling devices
• CPC Class Codes: A61M 16/0093 by adsorption, absorption or filtration
• CPC Class Codes: A61M 16/1015 using a gas flush valve, e.g. oxygen flush valve
• CPC Class Codes: A61M 16/104 specially adapted for anaesthetics A61M16/18 takes precedence
• CPC Class Codes: A61M 16/18 Vaporising devices for anaesthetic preparations
• CPC Class Codes: A61M 2205/84 for treating several patients simultaneously

Abstract

A method and apparatus for anesthetizing one or more laboratory animals is provided. An anesthetic component is introduced into a pressurized gas stream for delivery to laboratory animals. In one embodiment of the invention, a solo apparatus is used to administer anesthetic component to a single animal. The apparatus may also contain a host cage providing a group apparatus connected to the pressurized gas stream that permits administration of anesthesia to one or a group of animals simultaneously. One or more solo and/or group apparatuses may be used to administer anesthetic components to different animals at various dosages. The apparatus may also include a thermoregulatory system that transfers heat to animals as they receive anesthesia to control the animals'"'"' body temperature. In addition, the apparatus may include an exhaust system to remove contaminants from exhaust gases and to withdraw exhaust gases from the apparatus or apparatuses.

Claims

1. An apparatus for anesthetizing a first laboratory animal having a breathing passage, the apparatus, comprising:

a source of a pressurized gas;

a vaporizer fluidly connected to said source and adapted to introduce an anesthetic component into the pressurized gas stream to create an anesthetic gas mixture;

a manifold connected to said vaporizer receiving said gas mixture and having multiple outlet ports operable to deliver the gas mixture through said ports simultaneously;

a first breathing device connected to a first of said outlet ports, said first breathing device comprising a shroud forming an air-exchange chamber for transferring gas to and from the first animal'"'"'s breathing passage, said shroud comprising an inlet port for permitting gas to flow into the chamber, and an exhaust port for permitting gas to evacuate the chamber; and

a check valve connected with the inlet port and extending within the shroud in operable communication with the animal'"'"'s breathing passage, said check valve being operable in an open position only when the first animal inhales to permit anesthetic gas mixture to flow into the chamber, and in a closed position when the first animal exhales to prevent the anesthetic gas mixture from entering the chamber,

wherein said exhaust port is operable to evacuate substantially all exhaust and accumulated gas from the chamber when the check valve is in the closed position to minimize the animal'"'"'s re-inhailing of carbon-dioxide and anesthetic gas mixture exhaled into the chamber.

2. The apparatus of claim 1 comprising a second breathing device connected to a second of said outlet ports and configured to deliver the gas mixture to a second animal.

3. The apparatus of claim 2 wherein the second breathing device comprises an imperforate container having a substantially sealed environment adapted to enclose one or more animals, said container having an inlet to introduce the gas mixture into the sealed environment for inhalation by the animal or animals.

4. The apparatus of claim 3 comprising an animal support base and a thermoregulatory system for transferring heat to the exterior of the support base, and wherein the container has a pocket configured to fit snugly over the support base to enable heat transfer from the base to the container.

5. The apparatus of claim 4 wherein the container has an opening adapted to permit passage of an animal to and from the container, and a lid configured for placement over the opening to maintain said sealed environment for receiving the gas mixture.

6. The apparatus of claim 4 wherein the container has a container exhaust port to discharge gases exhaled by the one or more animals, and including a filter cartridge connected to said container exhaust port to filter out contaminants contained in the exhaled gases.

7. The apparatus of claim 3 wherein the container inlet comprises a check valve that controls the flow of the gas mixture into said sealed environment.

8. The apparatus of claim 2 comprising a bypass line connected to said source of pressurized gas, said bypass line being configured to deliver pressurized gas to one of said first and second breathing devices as a replacement for said gas mixture, said replacement gas having constituents for enabling rapid recovery of the animal from the effects of the gas mixture upon the animal.

9. The apparatus of claim 1 comprising a thermoregulatory system adapted to maintain the body temperature of the first animal, said thermoregulatory system comprising a base configured to support the first animal in a position to receive the gas mixture delivered by the first breathing device, a supply of fluid heat exchange medium, a circulator, and an inlet and an outlet in said base to circulate said heat exchange medium through said base to transfer heat to the exterior of said base and to the animal supported by said support.

10. The apparatus of claim 9 wherein the circulator comprises a pump having a reservoir for the fluid heat exchange medium, and a heating element in said reservoir, said heating element being configured to heat the fluid media, and said pump being configured to circulate the heated fluid medium through said inlet and said outlet.

11. The apparatus of claim 10 wherein said inlet and outlet are connected in a closed loop to said pump reservoir whereby said fluid medium is recirculated in said closed loop from said pump, through said base and back to said pump.

12. The apparatus of claim 1 wherein the first breathing device comprises a plurality of masks, each mask having one end configured to conform to the anatomy of a different animal, and a second end adapted to connect to said chamber, such that when one of said masks is connected to said chamber, gas in said chamber is delivered to the nose of the animal;

said chamber having a filter cartridge connected to said exhaust port.

13. The apparatus of claim 12 wherein the second end of each of said plurality of masks is the same as the second end of the others of said plurality of masks to enable substitution of one mask for another.

14. The apparatus of claim 12 wherein the chamber is configured to receive gases exhaled by the animal through the mask, said check valve enabling the flow of the gas mixture into the chamber for delivery to the animal, and preventing reverse flow of the exhaled gases.

15. The apparatus of claim 14 including a filter cartridge connected to said exhaust port to filter out contaminants contained in the exhaled gases.

16. The apparatus of claim 15 wherein said filter cartridge includes a sensor to sense the condition of the gases passing through the cartridge, said sensor including an indicator to signal when the condition of the gases makes it desirable to service the filter.

17. The apparatus of claim 1 comprising an exhaust system configured to remove gas emissions generated in the first breathing device, said system comprising a filter cartridge having an inflow end connected to said first breathing device, a filter media within said cartridge adapted to remove contaminants in the gas emissions, an indicator that monitors the absorptive capacity of the filter media and generates a warning signal which corresponds to the condition of the filter media, said signal comprising at least one of an auditory signal and a visual signal.

18. The apparatus of claim 17 wherein said filter cartridge has an effluent end, said apparatus including a housing coupled to the effluent end of the cartridge, said housing supporting said indicator, said indicator including a sensor adapted to transmit an electronic warning signal when the sensor detects a concentration of contaminants in excess of a selected level, and a signaling device to generate said auditory or visual signal when said sensor transmits the electronic signal.

19. An apparatus for anesthetizing one or more laboratory animals having a respiratory system, the apparatus comprising:

a source of a pressurized gas;

a vaporizer fluidly connected to said source and adapted to introduce an anesthetic component into the pressurized gas stream to create an anesthetic gas mixture;

a manifold connected to said vaporizer receiving said gas mixture and having multiple outlet ports operable to deliver the gas mixture through said ports simultaneously;

a first animal support having a first breathing device connected to a first of said outlet ports and configured to deliver the gas mixture to an animal'"'"'s respiratory system;

a second animal support having a second breathing device connected to a second of said outlet ports and configured to deliver the gas mixture to an animal'"'"'s respiratory system;

a thermoregulatory system for each of said animal supports adapted to control the temperature of its associated support to maintain the body temperature of an animal supported by said support at a selected temperature; and

an exhaust system comprising a negative pressure recapture system, said recapture system including a perforated grid, a tray having a bottom surface and configured to support the grid in a substantially horizontal position above said surface to provide a plenum, one or more conduits connected to said plenum, and means for generating negative pressure in the plenum and conduits, at least one of said animal supports being disposed adjacent said perforated grid, whereby the negative pressure draws gas emissions into said plenum from around said adjacent animal support.

20. The apparatus of claim 19 wherein said grid has an opening conforming to the outline of said adjacent animal support, aid support being positioned within said opening whereby the grid surrounding said adjacent support creates a flow of ambient air into said plenum around the perimeter of said adjacent animal support, said ambient air entraining gas emissions from said adjacent animal support.

21. An apparatus for anesthetizing a laboratory test animal having a breathing passage, the apparatus, comprising:

a source of an anesthetic gas mixture;

a breathing device having a fluid connection to said source to deliver the gas mixture to the breathing passage, said breathing device comprising a base configured to support the test animal in a position to receive the gas mixture;

a thermoregulatory system adapted to control the temperature of said base to maintain the body temperature of the test animal supported by said base at a selected temperature, said thermoregulatory system including a supply of fluid heat exchange medium, a circulator, and an inlet and an outlet in said base to circulate said heat exchange medium through said base to transfer heat to the exterior of said base and to the test animal;

said breathing device comprising a shroud that forms an air exchange chamber and a plurality of masks, each mask having one end configured to conform to the anatomy of a different animal, and a second end adapted to connect to said chamber, such that when one of said masks is connected to said chamber gas in said chamber is delivered to the nose of the animal through said one mask, and exhaled gases of the test animal are discharged into said chamber, said chamber having a chamber inlet and a chamber outlet;

a check valve connected with the chamber inlet and extending within the shroud in operable communication with the test animal'"'"'s breathing passage, said check valve being operable in an open position only when the test animal inhales to permit anesthetic gas mixture to flow into the chamber, and in a closed position when the test animal exhales to prevent the anesthetic gas mixture from entering the chamber,

wherein said chamber outlet is configured to evacuate substantially all exhaust and accumulated gas from the chamber when the check valve is in the closed position to minimize the animal'"'"'s re-inhailing of carbon-dioxide and anesthetic gas mixture exhaled into the chamber.

22. The apparatus of claim 21 wherein the second end of each of said plurality of masks is the same as the second end of the others of said plurality of masks to enable substitution of another mask for said one mask.

23. The apparatus of claim 21 including a filter cartridge connected to said chamber outlet to filter out contaminants contained in the exhaled gases, said cartridge including a sensor to sense the condition of the gases passing through the cartridge, and an indicator to signal when the condition of the gases makes it desirable to service the filter.

24. An apparatus for anesthetizing a laboratory test animal having a respiratory system, the apparatus, comprising:

a source of an anesthetic gas mixture;

an animal support for the test animal having a breathing device having a fluid connection to said source to deliver the gas mixture to an animal'"'"'s respiratory system, said animal support comprising a base configured to support the test animal in a position to receive the gas mixture; and

a thermoregulatory system for said animal support adapted to control the temperature of said base to maintain the body temperature of the test animal supported by said base at a selected temperature, said thermoregulatory system including a supply of fluid heat exchange medium, a circulator, and an inlet and an outlet in said base to circulate said heat exchange medium through said base to transfer heat to the exterior of said base and to the test animal;

said breathing device comprising an air exchange chamber and a plurality of masks, each mask having one end configured to conform to the anatomy of a different animal, and a second end adapted to connect to said chamber, such that when one of said masks is connected to said chamber, gas in said chamber is delivered to the nose of the animal through said one mask, and exhaled gases of the test animal are discharged into said chamber, said chamber having a chamber outlet, said fluid connection including a check valve to allow unidirectional flow of the gas mixture into said chamber, said check valve enabling the flow of the gas mixture into the chamber for delivery to the test animal, and preventing reverse flow of exhaled gases through said connection, and causing said exhaled gases to flow through said chamber outlet, wherein said animal support base has a hollow interior connected to said thermoregulatory system, and a channeled first side and a flat second side, providing alternate areas for supporting the test animal.

25. An apparatus for anesthetizing one or more laboratory animals having a respiratory system, the apparatus, comprising:

a source of a pressurized gas;

a vaporizer fluidly connected to said source and adapted to introduce an anesthetic component into the pressurized gas stream to create an anesthetic gas mixture;

a manifold connected to said vaporizer receiving said gas mixture and having multiple outlet ports operable to deliver the gas mixture through said ports simultaneously;

a first animal support having a first breathing device connected to a first of said outlet ports and configured to deliver the gas mixture to an animal'"'"'s respiratory system, said first breathing device comprising an air exchange chamber and a mask having one end configured to conform to the anatomy of a test animal, and a second end adapted to connect to said chamber, such that gas in said chamber is delivered to the nose of the animal;

said chamber having a fluid connection to one of said outlet ports, said fluid connection including a check valve to allow unidirectional flow of the gas mixture into said chamber, said fluid connections throttling the unidirectional flow from said manifold to maintain the pressure of the gas mixture in said chamber below 1 mm.Hg; and

a second animal support having a second breathing device connected to a second of said outlet ports and configured to deliver the gas mixture to an animal'"'"'s respiratory system, said second breathing device comprising an imperforate container having a substantially sealed environment adapted to enclose one or more animals, said container having an inlet to introduce the gas mixture into the sealed environment for inhalation by the animal or animals, and fluid connections including a flow regulator connected to said manifold to afford flow of the gas mixture from said manifold into said container,

said manifold receiving the gas mixture at a pressure at least five times greater than the pressure of the gas mixture in said chamber of the first breathing device.

26. The apparatus of claim 25 wherein said first breathing device comprises a plurality of masks,

each mask having one end configured to conform to the anatomy of a different animal, and a second end adapted to connect to said chamber, the second end of each of said plurality of masks being the same as the second end of the others of said plurality of masks to enable substitution of one mask for another.

27. The apparatus of claim 25 wherein said chamber is configured to receive gases exhaled by the animal through the mask, said check valve enabling the flow of the gas mixture into the chamber for delivery to the animal, and preventing reverse flow of the exhaled gases, said chamber having an exhaust port to discharge gases exhaled by the animal, and including a filter cartridge connected to said exhaust port to filter out contaminants contained in the exhaled gases.

28. The apparatus of claim 27 wherein said filter cartridge includes a sensor to sense the condition of the gases passing through the cartridge, said sensor including an indicator to signal when the condition of the gases makes it desirable to service the filter.

29. A method of anesthetizing laboratory animals, comprising the steps of

providing an animal support having a hollow base with a channeled first side and a flat second side, and placing a live test animal having a functioning respiratory system on a given one of the first and second sides of the animal support,

providing a delivery system for delivering an anesthetic gas mixture to the animal'"'"'s respiratory system;

regulating the test animal'"'"'s body temperature condition during the delivery of the anesthetic compound by circulating heat exchange medium through said hollow base, and transferring heat from said heat exchange medium to the animal through said given side of the animal support; and

capturing gases exhaled by the animal'"'"'s respiratory system.

30. The method of claim 29 wherein the given side is the flat side of the base, and including the further steps of

performing a test procedure on the animal after it is anesthetized, and

following performance of the test procedure, transferring the animal to the channeled side of the base.

31. A method of anesthetizing a plurality of laboratory animals, comprising the steps of

providing a solo animal support apparatus having a hollow base and a mask, and placing a live test animal having a functioning respiratory system on the hollow base with its respiratory system open to the interior of the mask,

providing a laboratory enclosure having a bottom to constitute a group animal support apparatus, and placing one or more live test animals in said enclosure,

providing a delivery system for delivering an anesthetic gas mixture to the respiratory system of the animals through the mask in the solo apparatus and through said enclosure in the group apparatus;

maintaining the pressure of the gas mixture in the mask to less than 1 mm.Hg, and maintaining the pressure of the gas mixture in the enclosure in the range of 6 to 12 mm.Hg,

regulating the test animal'"'"'s body temperature condition during the delivery of the anesthetic compound by circulating heat exchange medium through the hollow base, and transferring heat from the heat exchange medium to the animal through the given side of the animal support; and

capturing gases exhaled by the animal'"'"'s respiratory system.

32. A method according to claim 31 including the steps of

providing a second hollow base adjoining the bottom of the enclosure, and

regulating the body temperature of the one or more test animals in the enclosure during the delivery of the anesthetic compound by circulating heat exchange medium through the second hollow base, and transferring heat from the heat exchange medium to the one or more animals through the bottom of the enclosure.