Chapter 15- Anaesthesia Flashcards
What’s general anaesthesia
Puts you into a sleep state
How general anaesthesia usually administered
IV or a volatile gas
Short acting opioid may be used
How is the affect of general anaesthetic reversed
AChE or specific antagonist can be given to quickly reverse the effects
How does local anaesthesia work
Blocking conduction of nerve fibres
How is local anaesthesia administered
Injections may be given or combined with adrenaline for local vasoconstriction
This limits systemic absorption and prolongs local activity
Why might benzo be administered in an anaesthetic setting
Has no analgesic properties but used due to sedation, amnesia and anxiolytic properties
What’s used to antagonise benzos effects
Flumazenil
What can corticosteroids combines with anaesthetics cause
A dangerous fall in blood pressure
What medications should be stopped before going under general anaesthesia
Combined oral contraceptives
Hormone replacement therapy
Antidepressants (MAOI and sometimes TCA)
Lithium (24hrs before)
Potassium sparing drugs
Antiplatelets/ oral anticoagulation (convert to heparin)
Diabetes meds (switch to insulin)
What should be cautioned with anaesthesia and driving
Responsible person to take them hime
Avoid alcohol
Risk extends to Atleast 24hours after
When should lithium be stopped before major surgery?
24 hours before
How are patients on potassium sparing diuretics managed for surgery?
Stop it the morning of surgery
How are patients on ACEi and ARBs managed for surgery?Why?
Discontinue 24 hours before surgery Severe hypotension can occur after induction of anaesthesia
Do local anaesthetics cause dilation or constriction of blood vessels?
Dilation
Why is adrenaline added to local anasethetic?What is the risk?
Diminishes local blood flow, slowing the rate of absorption and thereby prolonging the anaesthetic effect. The risk is ischaemic necrosis so should not be given in digits (toes and fingers) or appendages
