Breathing systems Flashcards
FGF
= fresh gas flow
TV
= tidal volume
MV
= minute volume
SF
= system factor
IPPV
= intermittent positive pressure ventilation
APL Valve
= adjustable pressure limiting valve
What are the available non-rebreathing systems?
- T-piece
- Lack or mini lack
- bain
What is the available rebreathing system?
- circle
Which breathing systems can you use for IPPV?
- t-piece
- bain
- circle
Which breathing systems are not suitable for IPPV?
- lack or mini lack
T-piece: pt size
- <10kg
T-piece: SF
- 2.5
What does T-piece look like?
- reservoir bag on expiratory limb, 1 long tube and a short tube
Why is lack/mini lack more oxygen efficient that t-piece or Bain?
- lower SF
Standard lack: pt size
- > 10kg
Mini lack: pt size
- 2-10kg
Lack/mini lack: SF
- 1
What does a lack/mini-lack look like?
- 2 parallel tubes
What does a Bain look like?
- tube within a tube
– internal tube supplies gas
Bain: pt size
- 10-30kg
Bain: SF
- 2.5
What does a Bain rely on?
- high FGF
Formula for FGF for non-rebreathing systems
- MV x SF
Formula for MV
- TV x RR (20bpm)
TV
- 10ml/kg
Circle: pt size
- standard circle: 10-150kg
- paediatric tubing: 2-10kg
What has to be checked and changed regularly with a circle?
- the soda lime
– it absorbs the CO2
Calculations for rebreathing systems: first 10-15mins
- 100ml/kg/min
– flood the pt with anaesthetic agent to take over job of induction agent
– de-nitrogenation
Calculations for rebreathing systems: maintenance
- 10ml.kg.min
– only when have a low flow flowmeter
Calculations for rebreathing systems: reservoir bags
- TV x 4
Use of Humphrey ADE circle
- can be non-rebreathing for smaller pts (similar to lack)
- rebreathing for larger pts
- designed for out in field
- able to use for MRI
- low FGF rates
- rate
Use of induction chambers
- can reduce stress of handling
– but can be stressful if used incorrectly - can dry out eyes
- H&S concern when opening lid
