The Conduct of General Anaesthesia

Question 1

what areas of medicine are anaesthetists involved with?

Answer 1

• pre-operative assessment
• perioperative medicine
• pain medicine
• critical care/intensive care medicine
• anaesthesia

Question 2

describe the phases of anaesthesia

Question 3

discuss the care of the unconscious patient

Question 4

what are the stages and phases of general anaesthesia?

Answer 4

• pre-op assessment and planning
• preparation
• induction
• maintenance
• emergence
• recovery
• post-operative care

Question 5

what monitoring takes place when a patient is anaesthetised?

Answer 5

• ECG
• BP (non-invasive)
• oxygen sats
• end-tidal CO2 (ETCO2)
• airway pressure

Question 6

why do we give supplemental oxygen before anaesthetising a patient?

Answer 6

Pre-oxygenation:
- increases time to desaturation
- reduced functional residual capacity under anaesthesia

Question 7

which drugs are given during the induction stage of general anaesthesia?

Answer 7

Analgesic:
- fentanyl
- alfentanil

Hypnotic:
- propofol
- thiopentone
- ketamine

• muscle relaxant

Question 8

what are the different planes of anaesthesia?

Answer 8

1. analgesia and amnesia
2. delirium to unconsciousness
3. surgical anaesthesia
4. apnoea to death

Question 9

what are the reasons for intubate a patient during general anaesthesia?

Answer 9

• protection from aspiration
• need for muscle relaxation
• shared airway
• need for tight CO2 control
• minimal access to patient

Question 10

what risks are associated with general anaesthesia drugs?

Answer 10

• anaphylaxis
• regurgitation and aspiration
• airway obstruction and hypoxia
• laryngospasm
• cardiovascular instability
• rarely, cardiac arrest

Question 11

in what ways can we control circulation during anaesthesia?

Answer 11

• control of haemodynamics: BP at least every 5 minutes
• vasoactive drugs

Question 12

what are other, non-drug related risks of anaesthesia?

Answer 12

• awareness e.g. waking up
• eye injury (1:100-1:4)
• hypothermia (1:25-1:2)
• pressure injury (1:5)
• VTE (1:100-1:4)
• nerve injury (1:1000)

Question 13

what is the anaesthetist doing during surgery?

Answer 13

Maintenance of anaesthesia:
- continuous IV anaesthesia
- vapour (‘gas’)

• Being vigilant in case anything goes wrong > have to act quickly.
• constant adjustement of drugs.
• anticipation (blood loss/fluid shifts/major events)

Planning for end of surgery:
- analgesia
- anti-emesis
- documentation
- communication with team
- advocacy while patient is unconscious

Question 14

what documentation is being filled in by anaesthetist during patients surgery?

Answer 14

• prescription recor
• obs chart
• ventilation chart
• fluid balance

Question 15

what are the steps in the emergence phase of anaesthesia?

Answer 15

• theatre ‘sign out’
• reversal of neuromuscular blockade
• anaesthetic agent stopped
• return of spontaneous breathing
• return of airway reflexes
• suctioning and removal of airway device
• transfer to recovery room