Patent ID: 6874500

Claim:
A ventilation or anesthesia system, comprising a recirculation module, a rebreathing tube operatively connected at its proximal end opening to the recirculation module for providing expired gases to and receiving gases from the recirculation module, and a distal output for fresh gases, wherein said distal output is located in the distal portion of said rebreathing tube or in a distal fitting operatively connected to said distal end of said rebreathing tube, wherein said rebreathing tube has an adjustable volume proximal of said distal output, wherein the concentration of fresh gases administered to a patient or mammal connected to said system relative to gases that a patient may rebreath may be adjusted by adjustment of the volume of said rebreathing tube volume proximal of said distal output, wherein when the volume of said rebreathing tube is adjusted said rebreathing tube substantially retains the adjusted volume.