w/c 27-Jan-14 Flashcards
(93 cards)
What are the three components of general anaesthesia?
1) unconsciousness -narcosis = lack of awareness
2) Analgesia (pain is a conscious perception) - antinocieption
3) Muscle relaxation
What is ‘balanced anaesthesia’
A movement away from using a single drug to do all three components we want from a GA.
It is a combination of drugs which reduces the side effects; allows ‘lightening up’
Which breed is said to be sensitive to acepromazine (ACP)?
Boxers are said to be susceptible to ACP
ACP is a sedative and an antiemetic
How many hours should be waited till GA in induced in dogs and cats?
Withhold food for 6 hours
According to statistics, which species is more likely to die under anaesthetic; cat or dog?
Healthy Cat: 1 in 895 die
Healthy Dog: 1 in 1849 die
Guinea Pig: 1 in 26 die
In the context of anaesthesia, what is the ASA score?
ASA score is a measure of the animals physical status
Dangers of nitrous oxide
More dangerous and can inhibit DNA synthesis and cause CNS damage.
What is the recommended maximum concentrations of anaesthetic gases?
Nitrous oxide:100ppm
Sevoflurane: 60ppm
Isoflurane: 50ppm
Halothane: 10ppm
A blue cylinder probably contains what gas?
What is important about this gas?
Nitrous oxide
Stored in a liquid phase with gas on the top. As long as some liquid is left, will always have a +ve pressure gauge. HAVE TO WEIGHT to determine amount left.
Significance of the Bodok seal
Must be placed between cylinder and anaesthetic machine to make a gas-tight join.
VERY LOAD NOISE if missing when cylinder turned on
Why does the vaporizer need to be kept upright?
Otherwise the bypass channel may flood with anaesthetic and dramatically increase output = DANGEROUS
Why do you need to be careful using emergency oxygen flush?
Oxygen is given at a pressure of 400kPa directly from the cylinder.(40 litres/minute)
Higher pressure= careful LUNG DAMAGE
What is a ‘low-resistant’ or ‘draw-over’ vaporizer?
Patients respiratory effort determines amount of anaesthetic agent breathed in.
Vaporiser is positioned WITHIN the anaesthetic circuit.
Anaesthesia too light = increased respiratory effort = sleep!
Advantage/Disadvantage of rebreathing system
ADVANTAGE: exothermic reaction when CO2 react.
Low volatile agent consumption
Most economical in large animal
DISADVANTAGE: Exact composition of gas is not known
Expensive
Slow to change depth of anaesthesia
Advantage/Disadvantage of non- rebreathing system
ADVANTAGE: Simple/cheap, inspired air composition is known, low resistance to breathing
DISADVANTAGE: High gas flow requirements
Expired heat loss
Breathing/Non-Rebreathing system can change depth of anaesthesia more quickly
Non rebreathing systems can change depth of anaesthesia more quickly
Which type of breathing system allows for heat to be retained?
Exothermic reaction between carbon dioxide and soda lime = REBREATHING SYSTEMS can RETAIN HEAT.
Most economic in large animals
Which set is best as IPPV?
IPPV: Intermittent Positive Pressure Ventilation
How are non-rebreathing sets classified?
Rebreathing of carbon dioxide is prevented by having enough fresh gas flow (FGF) into the circuit to wash away exhaled gas from previous exhalation.
Classified depending on FGF (Classification from A to F)
Which is the best sets for IPPV?
MAGILL and LACKS (not good for IPPV, as Mapleson classification A, need to increase FGF)
AYRE’ST PIECE/ BAIN (better for IPPV) as don’t need to increase FGF
IPPV: INTERMITTENT POSITIVE PRESSURE VENTILATION
Which set would be given for animals <10kg?
Ayre’ T-piece.
Good choice for IPPV (as already high FGF)
Low resistance to breathing.
When is the breathing set Humphrey ADE used?
Versatile system, by means of a lever switch system can be conversed from a Mapleson A to a Mapleson D or E.
i.e. A: good for spontaneous respiration
D/E good for controlled respiration
Why can circle rebreathing systems only be used in animals >10kg?
Gas can only move in one direction (i.e. a circle!)
Two way valves are present. Resistance to breathing is higher
What breathing set would you use for a 6kg Jack Russel?
Tpiece
minimal resistance