Anaesthesia & Surgery Flashcards
How do you manage local anaesthetic toxicity?
IV 20% lipid emulsion
Presents as CNS overactivity then depression and cardiac arrhythmias
When is bupivacaine used?
Longer DOA - used as topical wound infiltration at the end of surgical procedures
CARDIOTOXIC!! Contraindicated in regional blockage
Which local anaesthetic agent is used for regional anaesthesia eg. blocks?
Prilocaine
How is diabetes managed peri-operatively?
Metformin:
Day prior - take as normal
Day of - take as normal unless TDS (omit lunchtime dose)
Sulfonylureas:
Day prior - take as normal
Day of - omit morning dose (or both doses if afternoon surgery)
DDPIV/GLP-1 analgoues:
Take as normal throughout
SGLT2 inhibitors:
Day prior - take as normal
Day of - omit
Once daily insulins:
Reduce dose by 20% each day
Twice daily insulins:
Day prior - no dose change
Day of - halve the usual morning dose and leave evening dose unchanged
Those with major surgeries or poor control may need to go onto VRIII
What are some special preparations for certain surgical procedures?
- Thyroid surgery; vocal cord check.
- Parathyroid surgery; consider methylene blue to identify gland.
- Sentinel node biopsy; radioactive marker/ patent blue dye.
- Surgery involving the thoracic duct; consider administration of cream.
- Pheochromocytoma surgery; will need alpha and beta blockade.
- Surgery for carcinoid tumours; will need covering with octreotide.
- Colorectal cases; bowel preparation (especially left sided surgery)
- Thyrotoxicosis; lugols iodine/ medical therapy.
What are the different options for inhaled anaesthetics?
- Volatile liquid (isoflurane, desflurane) - used for induction and maintenance of anaesthesia, can cause myocardial depression and hyperthermia
- Nitrous oxide - used for maintenance of anaesthesia and analgesia
What are the different options for IV anaesthetics?
- Propofol
- Potentiates GABA
- Can cause hypotension
- Commonly used for induction and in ICU
- Some anti-emetic properties; good for pts who have previously had post op N&V - Thiopental
- Potentiates GABA
- Can cause larynogaspasm
- Quickly affects the brain - Etomidate
- Potentiates GABA
- Can cause primary adrenal suppression and mycolonus
- Causes less hypotension so can be used in cases of haemodynamic instability - Ketamine
- Blocks NMDA receptors
- Can cause disorientation and hallucinations
- No drop in BP, useful in trauma
What are the different options for airway management?
- Oropharyngeal airway (guedel)
- For very short procedures or as a bridge to more dfinitive airway - Laryngeal mask
- Used in day surgery, does not require paralysis - Trachoestomy
- Useful in slow weaning and ICU - Endotracheal tube
- Used in long and short term ventilation
- Errors in insertion may cause oesophageal intubation
- Requires paralysis
When should a COCP be stopped before surgery?
Stop 4 weeks pre-op
What LMWH is given post hip and knee replacements?
Elective hip:
- LMWH for 10 days followed by aspirin for 28 days
- LMWH for 28 days with TEDS until discharge
- Rivaroxaban
Elective knee:
- Aspirin for 14 days
- LMWH for 14 days with TEDS until discharge
- Rivaroxaban
Fragility fractures:
- Offer LMWH for a month
What is the Cushing’s reflex?
A physiological nervous system response to increased ICP.
Triad of:
1. Widening pulse pressure
2. Bradycardia
3. Irregular breathing
This is a sign of impending brain herniation
What is ECMO and when is it used?
Extracorporeal membrane oxygenation - technique of providing both cardiac and respiratory support oxygen to patients whose hearts and lungs are severely dysfunctional
eg. PPH, respiratory distress syndrome
