2016A02 Draw and label a circle breathing system. Explain its advantages and disadvantages.

 

List:

     Define

     Diagramme

     Pros

     Cons

 

Define:

Circle system is a semi-closed, re-breathing anaesthetic circuit.

 

Diagramme:

https://static.draeger.com/ventilation/Simulators/Primus/index.html#/en/page/D1100

(I strongly recommend you follow this link)

 

Pros:

Main features

  Volatile anaesthetic: accurate, minimal waste

  O2: accurate, can deliver 100%

  CO2: efficient removal by

o Scavenger (earlier in expiratory limb to spare CO2 absorber))

o CO2 absorber (later in expiratory limb)

Secondary features

  Minimal dead space: only tubing distal to Y piece and HME

  Low resistance

  Humidification and warming by CO2 absorber

Logistics

  Sodalime remote from airway hence minimal dust inhalation

  ↓Waste

  ↓O2 pollution

 

Cons:

Main features

  Change in vapour dial slow to equilibrate with circuit and patient

  FiO2 can fall below 0.21 if low fresh gas flow rate and low fresh gas pO2 (since semi-closed)

  Sodalime degradation products: CO, Compound A

Secondary features

  Higher resistance than Mapleson E and F due to valves and longer tubing

  Possibility of injury if dysfunctional valves, scavenging system

Logistics

  Expensive

  Complicated

  Bulky

  Atmospheric pollution from scavenging

 

 

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