Induction Flashcards
Why should you use propofol within 24h of opening?
» Soyabean oil, glycerol, egg lecithin, no preservative, NaOH (changes pH)
» Supports bacteria and endotoxin
A multi-dose vial with preservative was available (‘Propoflo Plus’ – Zoetis) 28d shelf life
What are the induction properties of propofol?
» Rapid onset of action -rapid uptake by CNS
» Short period of unconsciousness (5-8 mins)
» Large volume of distribution (lipophilic)
» Rapid smooth emergence due to redistribution & efficient metabolism (hepatic and extra hepatic) metabolites inactive
Can you use propofol for TIVA?
Suitable for top ups or TIVA (total intravenous anaesthesia)
What is the effect of propofol on ICP?
↓ ICP (patients with raised and normal ICP (intra cranial pressure))
Can you use propofol in geriatric or renal problem animals?
» Decrease dose in old dogs & cats
» Fine for renal compromise & hepatopathy patients
What are some of the problems with propofol?
» Rigidity, twitching » Apnoea » Profound bradycardia » Care in hypoproteinaemia » Pain on injection
What steroid anaesthetic is available?
Alfaxalone
– Causes anaesthesia by activating the GABA (inhibitory) receptor
– Alfaxalone has a short plasma elimination half life and is cleared from the body relatively quickly
– Alfaxalone can be give as repeated boluses or as TIVA to maintain anaesthesia
What are some of the pros and cons of alfaxalone?
– Occasional apnoea is seen and IPPV may be necessary (less than propofol)
– The drug has good cardiovascular stability, causes no histamine release and produces good muscle relaxation
– Animals should not be disturbed during recovery as excitement can occur
What is IPPV?
IPPV = – intermittent positive pressure ventilation (giving a breath to the animal – by squeezing the reservoir bag on the circuit)
What is ketamine used for?
Weak organic base pH 3.5 that causes a Dissociative state
Invariably needs to be combined with something
What are the anaesthetic properties of ketamine?
– Rapid induction – Respiratory effects are mixed – bronchodilation and RR usually preserved but my stop! – GOOD ANALGESIA – CVS effects depend on dose – Muscle tone ↑ and jerky movements – Salivation and lacrimation ↑
How can you dilute ketamine?
– Ketamine can be diluted with sterile water or physiological saline
What are some of the problems with ketamine?
– Stormy recovery if disturbed or not adequately premedicated
– Depth assessment is different (eyes open)
– Corneal drying - use ‘Lacrilube’ or similar tears
– Vomiting common with alpha 2 combinations avoid in patients with GI obstruction
– Avoid in patients with ↑ ICP, ocular surgery, fever, hyperthyroids
What is Zoletil 100?
250 mg tiletamine and 250 mg zolazepam as powder per vial
Add 5 ml of sterile water to the powder the solution contains 100 mg / ml.
Indicated for dog/cat general anaesthesia
How are horses induced?
An intravenous agent is used – almost always
After an induction agent a horse becomes unconscious
The quality of induction is affected by the premedication
Anaesthesia is then maintained by incremental ‘top ups’ IV or by infusion (TIVA) or by inhalation agents
