premed, induction and safety check Flashcards
What is the aim of premedication?
To facilitate handling through sedation and/or tranquillization, provide analgesia, and MAC sparing effects.
What is the mode of action, time to onset and duration of ACP
- A1 antagonist, D, 5HT and H1 antagonist
- Onset is 5min IV and 30 - 60min IM.
- Duration of action 4-6 hours.
What are the contraindications for Acepromazine?
- Hypotension
- Hypovolemia
What are the side effects associated with Acepromazine?
- Vasodilation
- Tachycardia
What effects do alpha-2 agonists like medetomidine and dexmedetomidine have?
- Light to profound sedation depending on dose
- Bradycardia
- Hyperglycaemia
What are the characteristic of benzodiazepines when used for premedication
- Minimal cardiovascular effect
- Not good sedatives alone (may produce paradoxical excitement), combine with opioid, ketamine or alpha 2.
- Anxiolytic
- Can produce muscle relaxation
What is the propofol and its mechanism of action
Propofol is phenol derivative. It acts on the GABA receptor to increase chloride ion influx leading to hyperolarisation (less negative, less likely to fire)
What is the onset and duration of action for Propofol?
Onset 60 - 90 secs, Duration10-15 minutes
What are the side effects of Propofol?
- Respiratory depressant (+++)
- Apnoea
- Cardiovascular depressant (++)
- Hypotension (++)
What is the main contraindication for using Propofol?
Known hypersensitivity, care with hypotensive and brady cardic animals.
What technique should be used when administering Propofol?
Administer in small boluses to avoid severe hypotension and apnoea.
Also consider co-induction with midazolam to decrease dose and slow injection.
What is Alfaxalone and what is its mechanism of action
Alfaxalone id a progesterone derivative with a similar mechanism of action to propofol. Ie it sensitiises the GABA-A receptor to GABA causing increased chloride influx and depolarisation. At higher doses it can stimulate the receptor without presence of gaba
= hyperpolarisation (less negative, less likely to fire)
What are some advantages of Alfaxalone over Propofol?
Does not accumulate
Less cardiovascular depression/causes less brady cardia.
can still cause apnoea and respiratory depression.
What are the side effects of Alfaxalone?
- Respiratory depression (+)
- Apnoea (if fast bolus)
- Light cardiovascular depression (+)
What is the mechanism of actio of ketamine
NMDA receptor antagonist. Leads to a dissociative anaesthesia and analgesic effects.
Cant also stim sympathetic nervous system so tachycardia hypertension
What are some side effects of Ketamine?
- Tachycardia
- Hypertension
- Salivation
- Muscle rigidity
- Respiratory depression
- decreased seizure threshold
- mild myocardial depression
What are some contraindications for the use of ketamine
- Some cardiac diseases (HCM)
- Pheochromocytoma
- increased intracranial pressure
- increased intraocular pressure
Summarise the effects of Iso/Sevo on HR, BP, CO and SVT
What is important to note when monitoring the patient under anaesthesia indued with ketamine?
Muscle tone remains/enchanced, central eyes and reflexes (eg palpaebral, withdrawal are preserved)
Briefly summarise the areas in the anasthetic equipment checklist
There ate 11 to remember
- Machine connected and switched on.
- Piplines are correctly inserted into gas supply/reserve supply available.
- Check operation of flowmeters
- check vaporisor
- check breathing system, leaks, pipes bag etc.
- Ventilator configured correctly.
- Check scavenging
- all possibly required ancillary equipment is present and working.
- check that alternative means to ventilate patient are available.
- Check monitoring equipment working correctly and alarm limits
- Monitoring sheet and checklists prepared
