Anaesthetics Flashcards
Which anaesthetic agent is useful in patients who suffer from post-op nausea + vomiting?
propofol - is also an anti-emetic
What is thought to be the mechanism of action of volatile liquid anaesthetics (desflurane, isoflurane, sevoflurane)?
Exact mechanism of action unknown. May act via a combination of GABA, glycine and NDMA receptors
What are 3 adverse effects of volatile anaesthetic agents (desflurane etc.)?
- myocardial depression
- malignant hyperthermia
- halothane (not used comonly any more) hepatotoxic
What is thought to be the mechanism of action of nitrous oxide?
exact mechanism of action unknown. May act via a combination of NDMA, nACh, 5-HT3, GABA and glycine receptors
What is an adverse effect and therefore contraindication of nitrous oxide?
diffuses into gas filled compartments of the body therefore leading to an increase in pressure; should therefore be avoided in pneumothorax
What are 4 examples of intravenous antibiotics?
- propofol
- thiopental
- etomidate
- ketamine
What is the mechanism of action of propofol?
Potentiates GABA-A
What are 2 adverse effects of propofol?
- pain on injection - activation of pain receptor TRPA1
- hypotension
What are 2 situations when propofol is used?
- common induction agent
- used extensively in intensive care for ventilated patients
What is an additional effect, as well as being an anaesthetic agent, of propofol?
anti-emetic effects (useful in post-operative vomiting)
What is the mechanism of thiopental?
type of barbiturate - potentiates GABA-A
What is a side-effect of thiopental?
laryngospasm
Why does thiopental affect the brain quickly?
highly lipid-soluble
What is the mechanism of action of etomidate?
potentiates GABA-A
What are 2 adverse effects of etomidate?
- primary adrenal suppression (seoncdary to reversibly inhibiting 11β-hydroxylase)
- myoclonus
In which specific situation may etomidate be the induction agent of choice and why?
in cases of haemodynamic instability - causes less hypotension that propofol and thiopental during induction
What is the mechanism of action of ketamine?
blocks NMDA receptors
What are 2 adverse effects of ketamine?
disorientation
hallucinations
In what situation may ketamine be a useful anaesthetic / analgesic and why?
trauma - doesn’t cause a drop in blood pressure
What counts as clear fluids pre-op?
water, juice with no bits, coffee/tea without milk, ice lollies
What is the guidance for adjustments to metformin on for patients undergoing surgery?
- day prior to admission - take as normal
- day of surgery, morning op - if OD or BD take as normal, if TDS omit lunchtime dose
- day of surgery, afternoon op - if OD or BD take as normal, if TDS omit lunchtime dose
What is the guidance for adjustments to sulphonylureas on the day of surgery?
- day prior - take as normal
- day of surgery for morning op - if taken OD in morning, omit dose. if BD - omit morning dose
- dy of surgery for afternoon op - if OD in morning, omit dose. if BD omit both doses that day
What is adjustment to be made to DPP4 inhibitors (gliptins) in patients undergoing surgery?
- day before - take as normal
- day of (morning op) - take as normal
- day of (pm op) - take as normal
What is adjustment to be made to GLP1 analogues (e.g. exenatide) in patients undergoing surgery?
- day before - take as normal
- day of (morning op) - take as normal
- day of (pm op) - take as normal
