Anaesthetics Flashcards
How long after MI should surgery normally be delayed?
3-6 months
What considerations should be made pre-op for someone with AF?
- rate should be controlled to <100bpm
- if on warfarin, may need to be transferred to heparin depending on surgery
Should aspirin be stopped for surgery?
no, risk of thrombosis outweighs risk of bleeding, EXCEPT for surgeries on:
- brain
- spinal cord
- prostate
- if stopping, stop at least 5 days pre-op
Should statins be stopped for surgery?
no
Should CCBs be stopped for surgery?
no
Should ACEi be stopped for surgery?
- increased risk of profound hypotensive episodes with regional anaesthesia
- many anaesthetists will stop in patients at risk of major haemorrhage, or planned for epidural anaesthesia
- often omit the morning dose prior to surgery
Should warfarin be stopped for surgery?
- if surgery can be performed with high INR, continue (e.g. most dental and eye surgeries, most endoscopies)
- if risk of bleeding outweighs risk of thrombosis, stop 5 days pre-op
- don’t normally need additional anti-thrombosis (e.g. if simple AF) but if risk higher (e.g. abnormal valves, previous cardiovascular events), replace with SC high dose fractionated heparin given at home before admission
Should oral diabetic drugs be stopped for surgery?
normally:
- long-acting drugs are stopped
- short-acting insulin is administered by infusion if needed
How long before surgery can patients have clear fluids?
2 hours
How long before surgery can infants have breast milk?
4 hours
How long before surgery can infants have infant formula?
6 hours
How long before surgery can patients have a light meal?
6 hours
How to measure fasting time in trauma
fasting time = time interval between last oral intake and the injury (because trauma delays gastric emptying)
How can oral medications be taken within fasting time?
with 30ml of water up to 30 mins prior to surgery
What pH and volume of gastric content confer increased risk in surgery?
pH <2.5
volume >0.4ml/kg
Which drugs are used to control gastric acidity and/or volume for surgery, and when can they be given?
- antacids (immediately before anaesthesia)
- PPIs (90 mins before)
- prokinetics (90 mins before) but not reliable
- H2 antagonists (90 mins before)
Examples of antacids
- magnesium trisillicate
- aluminium hydroxide
- sodium citrate
Examples of prokinetics
- metoclopramide
- erythromycin
Who should vena caval filters be considered in?
recent VTE (<1 month) and anticoagulation CI
Size and gauge order of cannulas
Biggest to smallest (lowest to highest gauge)
```
Orange (14G
Grey (16G)
White) (17G)
Green (18G)
Pink (20G)
Blue (22G)
Yellow (24G)
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How to check if patient is normovolaemic before giving epidural top-up?
- do not rely on BP!
- CRT
- core-peripheral temp gradient
- urine output
- record of blood loss and fluid administration
BP monitoring and support after epidural top-up
5 min intervals for at least 20 mins
treat hypotension with vasopressors
Groups of antiemetics used for PONV
- 5HT3 antagonists
- H1 antagonists
- D2 antagonists
- dexamethasone
Example of an 5HT3 antagonist and when it is used
ondansetron - as a rescue antiemetic (rapid onset)
