REBREATHING APPARATUS FOR ANESTHESIA

• US 3,612,048 A
• Filed: 02/19/1970
• Issued: 10/12/1971
• Est. Priority Date: 02/19/1970
• Status: Expired due to Term

• Current Assignee: Kentaro Takaoka
• Original Assignee: Kentaro Takaoka
• Inventors: Takaoka, Kentaro
• Primary Examiner(s): Gaudet, Richard A.
• Assistant Examiner(s): Howell, Kyle L.
• Application Number:
  US05/012,598
• Time in Patent Office: 600 Days
• Field of Search: 128/188,185,195,202,205,211,145.7,191,191A
• US Class Current: 128/204.25
• CPC Class Codes: A61M 16/104 specially adapted for anaesthetics A61M16/18 takes precedence

Abstract

A device for recirculating air to a patient combining the simplicity of the to and fro type of apparatus with the advantages of the circle type. Dead space is avoided by use of two venturis which enhance flow rate through a canister of carbonic gas-absorbing material. The absence of valves lowers resistance and increases efficiency.

Claims

1. A rebreathing apparatus for the recirculation to a patient of air or air plus an anesthetic combined with fresh gases from a source of gases, of the type in which carbonic gas is removed from the gases exhaled by a patient, comprising:

a canister adapted to contain carbonic gas-absorbing material for purifying gases passing through it;

two hollow end parts mounted on opposite ends of the canister, one end part being fitted with a gas reservoir means and the other end part including an offtake tube connected to means adapted for delivery of gases to a patient;

an inlet tube on said one end part for admitting fresh gases under pressure and an outlet tube on said one end part aligned with the inlet tube, the inlet tube having an inwardly tapering orifice forming a venturi within the one end member for drawing gas circulated through the canister into a stream flowing from the inlet tube to the outlet tube;

means in communication with said other end part permitting controlled escape of gases from said other end part; and

conduit means extending from the outlet tube to the other end part adjacent the offtake tube for supplying a patient with recirculated gases mixed with fresh gases.

2. Apparatus according to claim 1 wherein said conduit means is a flexible tube extending longitudinally alongside the canister connected to said outlet tube and to an intake tube on said other end part, the intake tube lying perpendicular to the offtake tube.

3. Apparatus according to claim 2 wherein said intake tube has a tube portion extending within said other hollow end part, the tube portion having an opening directed toward the canister thus providing a second venturi for enhancing circulation.

4. Apparatus according to claim 1 including a perforated element extending transversely across the inside of the canister and a spring means for biasing the perforated member toward said other end part for compacting carbonic gas-absorbing materials within the canister.

5. Apparatus according to claim 1 wherein the canister is cylindrical, and the hollow end parts include truncated conical extensions terminating in hollow cylindrical members.

6. Apparatus according to claim 5 wherein said offtake tube extends perpendicularly from the hollow cylindrical member of said other end part.

7. Apparatus according to claim 1, wherein an inner end of said inlet tube and an inner end of said outlet tube are interfitted within a space defined inside said one hollow end part, a small chamber being defined by said outlet tube adjacent the point at which said inlet and outlet tubes are interfitted, said small chamber being in communication with the space defined within said one end part whereby recirculated gases may flow into the chamber from said space.

8. Apparatus according to claim 1 wherein said means permitting controlled escape of gases includes and exit valve having a plurality of apertures, the valve being selectively adjustable to bring one of said apertures into registry with an exhaust passage from said other end part for selectively controlling gas pressure to a patient.

9. Apparatus according to claim 1 wherein said gas reservoir means is an inflatable breathing bag.

10. Apparatus according to claim 1 wherein said canister includes two transversely extending perforated plates for containing said absorbing material therebetween, each of said plates having a centrally disposed baffle for preventing channeling of gases through the absorbing material.