Anaesthetics Flashcards
What are fasting rules for surgery?
- Fast from non-clear liquids/food for at least 6 hours before surgery
- May drink clear fluids until 2 hours before their operation
Which patients will require a variable rate intravenous insulin infusion (VRIII) during surgery?
- If require a long fasting period of more than one missed meal
- Poorly controlled diabetics
Which anti-diabetic drugs need to be omitted on the day of surgery?
- SGLT-2 inhibitors (-flozins)
- Sulphnylureas (if taken BD and surgery in the morning - can take evening dose)
What are the rules for metformin around surgery?
- Day before as normal
- On the day of - if taken OD/BD take as normal, if taken TDS omit lunchtime dose
What are the rules for once daily insulins around surgery (e.g. Lantus, Levemir)?
- Reduce dose by 20% the day before surgery and the day of
What are the rules for twice daily Biphasic or ultra-long acting insulins (e.g. Novomix 30, Humulin M3) around surgery?
- Day before as normal
- On the day of - halve the usual morning dose, leave evening dose unchanged
What are the rules for warfarin around surgery?
The last dose of warfarin should be given 6 days before (unless minor procedure - can be continued)
What are the rules for HRT/OCP around surgery?
Stop 4 wks before
What is malignant hyperthermia?
A condition often seen following administration of anaesthetic agents
What happens in malignant hyperthermia?
Excessive release of Ca2+ from the sarcoplasmic reticulum of skeletal muscle
How does malignant hyperthermia present?
Hyperpyrexia and muscle rigidity
Why is it important to ask patients about a FHx of malignant hyperthermia?
Susceptibility to malignant hyperthermia is inherited in an autosomal dominant fashion
What are causes of malignant hyperthermia? What is the management?
- Halothane, suxamethonium, antipsychotics
- Dantrolene - prevents Ca2+ release from the sarcoplasmic reticulum
