Anesthesia rebreathing apparatus

• US 4,051,847 A
• Filed: 10/24/1975
• Issued: 10/04/1977
• Est. Priority Date: 01/17/1972
• Status: Expired due to Term

• Current Assignee: Melvyn Lane Henkin
• Original Assignee: Melvyn Lane Henkin
• Inventors: Henkin, Melvyn Lane
• Primary Examiner(s): Michell, Robert W.
• Assistant Examiner(s): Recla, Henry J.
• Application Number:
  US05/622,382
• Time in Patent Office: 711 Days
• Field of Search: 128/188, 128/186, 128/193, 128/194, 128/195, 128/145.8, 128/145.6, 128/145.5, 128/147
• US Class Current: 128/202.22
• CPC Class Codes: A61M 16/0078 Breathing bags
• CPC Class Codes: A61M 16/08 Bellows; Connecting tubes having means for taking samples G01N1/22; Water traps; Patient circuits
• CPC Class Codes: A61M 16/0833 T- or Y-type connectors, e.g. Y-piece
• CPC Class Codes: A61M 16/104 specially adapted for anaesthetics A61M16/18 takes precedence
• CPC Class Codes: F16L 55/04 Devices damping pulsations or vibrations in fluids F16L55/02 takes precedence

Abstract

A general anesthesia rebreathing system comprised of a disposable portion adapted to be easily coupled to and decoupled from a permanent portion. The disposable portion includes conventional breathing tubing for coupling a source of fresh gas, as from an anesthesia machine, to a patient and in addition an overflow tube for coupling the patient end of the system to an overflow (pop-off) valve, preferably mounted on the machine and constituting part of the permanent portion. The overflow tube entrance is located close to the patient end of the system and in communication with the tubing which conveys expired gas to a reservoir, such as a conventional breathing bag, mounted at the machine end. The arrangement assures that the patient'"'"'s initially expired dead space gas is conveyed by the tubing to the reservoir with subsequently expired alveolar gas being exhausted through the overflow tube and pop-off valve. By preferentially exhausting alveolar gas in this manner, the need for using CO₂ absorber material within the system is minimized. For optimum performance, the pop-off valve is operable in two different modes, i.e. (1) as a manually controlled variable orifice and (2) as an automatically controlled valve responding to a positive control pressure. The source of control pressure is selectable by the attending anesthetist dependent on the type of ventilation being employed, i.e. spontaneous, manually assisted, or mechanically controlled.

Claims

1. In a general anesthesia rebreathing system including (1) patient airway communication means, (2) fresh gas supply means, (3) at least one elongated breathing tube coupling said patient airway communication means and said fresh gas supply means, and (4) overflow valve means coupled to said breathing tube for venting excess gas therefrom at a normally encountered predetermined pressure, the improvement comprising:

overpressure relief means including first and second valve surfaces for permitting gas flow therepast in response to a positive pressure differential thereacross greater than said predetermined pressure at which said overflow valve means vents excess gas from said breathing tube;

means exposing said first valve surface to the pressure within said patient airway communication means and said second valve surface to ambient pressure; and

means responsive to gas flow past said overpressure relief means for producing an audible alarm.

2. A general anesthesia rebreathing system including:

means for communicating with a patient'"'"'s airway;

fresh gas supply means;

at least one elongated breathing tube coupling said patient airway communication means and said fresh gas supply means;

overflow valve means coupled to said breathing tube for venting excess gas therefrom at a normally encountered predetermined pressure; and

means responsive to the pressure in said breathing tube exceeding a physiologically safe level, in excess of said predetermined pressure, for providing an audible alarm and for relieving pressure in said breathing tube.