IV and inhalational anaesthetics Flashcards
What drug is used for induction and maintenance using IV drugs alone?
Propofol
Which drug has:
- anti-emetic properties?
- what is it used for?
Propofol
- anti-emetic properties
- used for maintaining sedation on ITU, total IV anaesthesia, day case surgery
Which agent has a rapid sequence of induction?
- what are the disadvantages?
Sodium thiopentone
- marked myocardial depression
- metabolites accumulate quickly
- little analgesic effect
- unsuitable for a maintenance
Ketamine
- what is it used for?
- what are its advantages?
- what is its disadvantage?
Ketamine
Use: may be used as induction
Advantages:
- has moderate - strong analgesic properties
- produces little myocardial depression (useful in haemodynamically unstable patients)
Disadvantage:
- may produce dissociative anaesthesia -> nightmares, hallucinations, agitation (as a drug wears off)
Etomidate
- advantage (1)
- disadvantages (3)
Etomidate
Advantage: has a good cardiac profile (very little haemodynamic instability)
Disadvantages:
- no analgesic properties
- may result in adrenal suppression (even short use) -> therefore not used for maintenance
- post-op vomiting is common
Components of checklist before introduction of anaesthesia (7)
Before the induction of anaesthesia, the following must have been checked:
- Patient has confirmed: Site, identity, procedure, consent
- Site is marked
- Anaesthesia safety check completed
- Pulse oximeter is on patient and functioning
- Does the patient have a known allergy?
- Is there a difficult airway/aspiration risk?
- Is there a risk of > 500ml blood loss (7ml/kg in children)?
Mechanism of action of propofol
Not yet fully understood, thought to act on GABAA receptors and sodium channels on the reticular formation
What allergies predispose the patient to anaphylactic reaction with propofol use?
Egg and soy -> as propofol is mixed with the substances containing these components (poor solubility in the water)
Propofol infusion syndrome
- cause
- clinical features
- management
Propofol infusion syndrome
Etiology: high doses and prolonged administration of propofol
Clinical features: severe metabolic acidosis, rhabdomyolysis, renal failure, and/or cardiac failure (often fatal)
Management: discontinue propofol immediately, symptomatic treatment (catecholamines, fluid resuscitation)
Mechanism of action of Etomidate
Etomidate
MoA: GABA receptors in reticular formation
What’s Etomidate good for? Why?
Etomidate
It has the least effect on CVS (it does not cause depression of the myocardium)
* therefore used in anaesthesia of the patients with myocardial instability
Mechanism of action of Ketamine
Ketamine
MoA: NMDA receptor antagonist (type of glutamate receptor)
What’s the advantage of Ketamine over other anaesthetics in an emergency setting?
- it can be administrated IM (apart from IV) -> so if IV access is difficult we still can give it
- good for polytrauma and hypotensive patients -> it does not induce CV depression
What type of procedure Ketamine is good for?
What is other use of Ketamine (aside from surgeries)?
Ketamine
- short and painful procedures e.g. fracture reduction
*Ketamine used in treatment of resistant asthma
Mechanism of action of barbiturates
Barbiturates
MoA: enhance GABA action -> via increased duration of Cl channels opening -> hyperpolarisation of post-sympathetic neurones -> reduced neural excitability