anaesthesia breathing circuits

Question 1

function breathing systems

Answer 1

removal of carbon dioxide exhaled by patient
supply oxygen to the patient
supply anaesthetic gases to patient
to allow for intermittent positive pressure ventilation (IPPV) if needed

Question 2

Re-breathing

Answer 2

Circle
to -and- fro
Humphrey ADE circle system

Question 3

Non- rebreathing

Answer 3

Ayers modified t-piece
Bain
Lack
Magill
Humphrey ADE

Question 4

re - breathing circuit advantages

Answer 4

reduced environmental contamination with waste gases

require low gas flow rates reducing cost

reduced heat loss from patient, gases require less warming.

Question 5

non - breathing circuit disadvantages

Answer 5

increased environment contamination

potential of re - breathing if the patient breathes too rapidly

high gas flow rate increasing costs

Question 6

re - breathing circuit disadvantages

Answer 6

can be expensive to purchase

CO2 absorbent and valves create a resistance

Requires and understanding on how the circuit works

Question 7

non- breathing advantages

Answer 7

easy

cheap to purchase

minimal circuit resistance

Question 8

Ayers t - piece

Answer 8

advantages
-compact
- non expensive

disadvantages
-heavy
-Bag may get twisted to cause loss in oxygen

circuit factor - 2.5-3
weight range - <10kg

Question 9

Magill

Answer 9

Advantages
-inexpensive
-reasonable economy of gas use

disadvantages
-difficult to perform IPPV effectively

circuit factor - 1-1.5
weight range - 8 - 35kg

Question 10

coaxial/parallel lack

Answer 10

advantages
-Expiratory valve is located at the end of the circuit
- no valves near the face
- can be used with reasonable diameter tubing

disadvantages
-requires a high fresh gas flow
-inefficient for spontaneously breathing patients

circuit factor - 1-1.5
weight range - 10 - 40kg

Question 11

Mini Lack

Answer 11

advantages
-low resistance
-efficient

disadvantages
-tubing diameter
-body weight range
- not suitable for sustained positive pressure ventilation

circuit factor - 1-1.5
weight range - <10kg

Question 12

Bain

Answer 12

advantages
-compact and inexpensive
-low dead space
-low resistance to breathing

disadvantages
-high fresh gas flow

circuit factor - 2.5-3
weight range -10-30kg

Question 13

Circle system advantages

Answer 13

• less environmental contamination
• ideal for IPPV
• Reduced heat loss from patient
• low fresh gas flow requirements

Question 14

Circle system disadvantages

Answer 14

• cannisters are difficult to clean
• cannisters are often a source of gas leaks
• maintenance takes time and skill
  -unsuitable for hyperthermic patients

Question 15

Soda Lime

Answer 15

• Different makes of soda lime have different
  colour changes from fresh soda lime to
  exhausted soda lime
• White to purple or pink to white, the
  manufacturer’s instructions will indicate the
  expected colour change