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Demystifying Circle Breathing Systems - mockup

Demystifying Circle Breathing Systems: A Practical Overview

Courtney Scales DipVN, NCert(Anaesth), RVN
Clinical Educator (Anaesthesia)

Keith Simpson BVSc, MRCVS, MIET(Electronics) – Clinical Director

A circle breathing system, or rebreathing system, allows the patient’s expiratory breath to be recycled and rebreathed after the carbon dioxide (CO2) has been removed. It is removed via CO2 absorbing granules that are held within a canister, which the expiratory breath must pass through before being inhaled again. The unidirectional flow of gases is achieved with one-way inspiratory and expiratory valves. 

  • This circle system has maintenance flows of only 0.5-1L/minute.
  • Circle systems can be used in patients <10kg.
  • A reservoir bag only needs to be 2-5x the tidal volume.