Anaesthesia 4 Flashcards
CLASSIFICATION OF ANAESTHETIC CIRCUITS (OPEN)
Lint/gauze placed on the nose
and volatile anaesthetic agent dropped onto the material
CLASSIFICATION OF ANAESTHETIC CIRCUITS (Semi-open)
gauze placed inside a mask attached to oxygen
CLASSIFICATION OF ANAESTHETIC CIRCUITS (Semi-closed)
Non rebreathing circuit
CLASSIFICATION OF ANAESTHETIC CIRCUITS (closed)
rebreathing circuit
Mapleson
Non-Rebreathing Systems
A, (B, C no longer
used), D E F
Howto remember Mapleson classification
A= APL near patient
D = Distant APL valve
E = Everything absent (APL & bag)
F= Free flow (APL valve absent)
semi-closed circuits require high gas flow to prevent?
Re-breathing the carbon dioxide rich expired gas
Adjustable Pressure Limiting Valve AKA
APL valve
Pop off
Heidbrink
How to choose the correct Reservoir Bag
3 - 6 x the tidal volume.
Non-rebreathing Circuits Advantages
Low resistance (ideal for
small animals)
Changes in the settings are
almost immediate
Can use- Nitrous Oxide & Carbon Dioxide
Non rebreathing circuits disadvantages
High gas flow rates required.
High volatile agent consumption rate.
Expired moisture and heat loss
Ayres T-piece (E) & Jackson Rees
Modification (F) circuit factor advantages
2.5-3
animals <10kg
Minimal resistance
Jackson Rees ideal for IPPV
Modified Bain
(structure, animal weight?, circuit factor, main benefits)
- Coaxial
- Fresh gas (inner tube)
Expired gas (outer tube) - animals 10 - 25 kg
Circuit factor 2.5-3
-Parallel bain
less drag
Bag nearest machine
Ideal for IPPV
Magill
(weight of animals?, Circuit factor, main disadvantage)
animals 10 - 35 kg
Circuit factor = 1 - 1.5
Not good for IPPV
Lack
Outer tube(fresh gas) inner tube (expired gases)
- Animals 8 - 40 kg
Long tubing =drag
Mini Lack - <10kg
Suitable for IPPV
Rebreathing Systems general advantages
Flow rates are very low
animals 10-80kg
Low pollution
Preserves moisture and heat
What is Soda Lime made up of?
- Calcium Hydroxide - 90% (lime)
- Sodium Hydroxide - 5% (soda)
- Potassium hydroxide with Silicates - 1%
- Water – 4%
- pH indicators
Soda lime colour changes
- Pink to white
- White to purple
is soda lime acidic or alkaline
Alkaline
Circle System
- Higher gas flow rate (10 - 15 min) then decrease the gas flow
- Circuit factor = 0.3 X minute volume
F Circuit
coaxial
Patient attached at coaxial end/ diverges-machine attached to outer tubing.
Less drag- one length tubing
thermally efficient
Humphrey ADE System
Combination of Mapleson A: (Magill and Lack), Mapleson D: (Bain) and Mapleson E: (T-Piece)
Exhaust Valve
central spindle of the
valve
Soda Lime Canister
Contains 500 grams of soda lime Last 8-12 hours
What parts requires annual maintenance on the Humphrey ADE?
- The brass cylinder inside the main body
- The exhaust valve
- The soda lime canister