Non-Rebreathing System  Used for patients weighing < 7 kg  Attach the clear, plastic hose to the fresh gas inlet (this tube comes from the vaporizer outlet port)  Flow of gas differs from rebreathing circuit now!  Fresh gas goes directly to the patient  Exhaled gas comes directly out through a separate hose and goes into a reservoir bag or sent through another tube to be scavenged

Non-Rebreathing System  Benefit: Less parts = less resistance Smaller animals need this feature!  Negative: Higher amount of oxygen used due to patient not-rebreathing any gas Patient is only breathing cool, dry fresh gas Warm, moist exhaled gases don’t meet

Non-rebreathing Systems Jackson-Rees Norman Mask Elbow

Non-rebreathing Systems Bain coaxial Ayre’s T-Piece Does not have a reservoir bag

Oxygen Flow Rates  Non-rebreathing system: 250 ml/kg/min  High b/c removal of CO 2 is dependent on flow in the system  Can go up to 600 ml/kg/min! Note: An inadequate fresh gas supply will result in your patient re-breathing gases…remember, there is no CO 2 absorber!

Things to Consider  Which breathing system may help keep a patient from becoming hypothermic?  Which breathing system is more costly to use?  Which breathing system allows for the quickest change in anesthetic depth?