Cicuits Flashcards
(23 cards)
How do non-rebreathing circuits operate
Rely on high FGF to flush expired CO2 from system do it cannot be re-breathed
Ayre’s t-piece features (3)
Small animals <10kg
High FGFR
Suitable for IPPV
Ayre’s t-piece circuit factor
2.5-3
Bain features (4)
larger patients >10kg
Double tubing
High FGFR
Suitable for IPPV
Bain circuit factor
2.5-3
Check specific to Bain
Check that inner tube not detached from system
Magill features (3)
patients >10kg
Lower FGFR than t-piece and Bain
Not suitable for prolonged IPPV
Magill circuit factor
1-1.5
Parallel lack features (3)
For patients >10kg
More economical than Bain for large patients
- lower FGFR
Not suitable for prolonged IPPV
Mini-lack features (3)
For patients <10kg
Lower FGFR
Not suitable for prolonged IPPV
Parallel and mini-lack circuit factor
1-1.5
Advantages of non-rebreathing circuits (6)
Simple construction
Inexpensive
No soda lime
Lower resistance than RB
- some good for small patients
Inspired gas volume comparable to vaporiser setting
Volatile agent concentration can be altered rapidly
Disadvantages of NRB circuits (4)
High FGFR High volatile agent consumption Expired moisture and heat loss - cold inspired gas Different FGFR required for different circuits
Re-breathing circuit features (3)
Requires lower FGFR
Higher resistance
- unsuitable for small patients
Allows conservation of heat and moisture
Circle features (7)
High resistance Soda lime absorbs CO2 For patients <10kg - more economical than Bain/lack Preserves exhaled heat and moisture Less pollution Cost efficient re. O2 and VA
Circle FGFR
100ml/kg/min ~15mins
10ml/kg/min after ~15mins
Humphrey ADE features (6)
Adjustable lever and detachable SLC allows use as RB or NRB
Adjustable level allows IPPV
Can use SLC to act as circle
Suitable for wide range of patient weights
Economical
- can be run at low FGFR
Preserves expired heat and moisture
Soda lime checks and when should be changed and how
Checked regularly for - cracks - exhaustion Changed at 2/3 exhausted Gloves and mask worn to change
Advantages of RB circuits (4)
Lower FGFR Economical - lower O2 and VA consumption Expired heat and moisture conserved Less pollution than other systems
Disadvantages of RB circuits (5)
Expensive to buy
Higher resistance
Soda lime must be changed regularly
Changes in vaporiser level slow to alter depth
N2O cannot be used in low-flow closed systems
Circuit safety checks (6)
Correct assemble Kinks and damage Contamination of tubing or bag Leak test APL valve open Check soda lime
Reason for use of induction chamber
For small mammals where restrain difficult or overly stressful
Features of induction chamber (5)
Airtight Transparent to allow monitoring Durable material Inlet for VA / outlet for waste gas High risk of environmental pollution
