General Anaesthesia

Question 1

Purpose of GA

Give examples

Answer 1

Accommodate for limited tolerance of extensive treatments
Brief painful procedures
Total lack of patient cooperation

Question 2

Purpose of sedation

Things to consider?

Answer 2

Reduce patient anxiety 
Increased tolerance of prolonged treatments 
Anxiolysis
Cooperation 
Street fitness 

Not always effective in long term

Question 3

Sedation drugs

Give examples

Answer 3

Alcohol - nausea, slow recovery
Tetrahydrocannabinol (THC)
Opiates - euphoria, depression
Major tranquillisers - anxiety and hypotension
Minor tranquillisers - benzodiazepines - drowsiness and prolonged effect

Question 4

Benzodiazepines

Two administrations
Features of both

Answer 4

Long interval, variable, small effect

IV

• competent cannulation
• limited duration of action
• need for monitoring SpO2
• written record of pulse and BP SpO2

Question 5

3 benzos
Mechanism
Characteristics

Answer 5

Change frequency of opening of chloride channels which leads to CNS depression
Diazepam - irritant, skin necrosis
Midazolam - slower onset, less predictable effect, rapid metabolism
Diazemuls - rapid onset, brief duration of action, psychoactive metabolites with long half life

Question 6

Sedation with propofol

Mechanism

Can be used in ….. doses

However?

Answer 6

works at least partly via GABA receptor. Short acting and fast recovery
Sub anaesthetic

No analgesia with it
continuous infusion via IV
Expensive delivery system

Question 7

Difference between sleep and unconsciousness

Answer 7

Unrousability

loss of protective reflexes

Question 8

Process of GA

Answer 8

Induction
Secure airway
Maintenance
Emergence

Question 9

Induction step

Route

What is the volatile agent

Answer 9

Propofol, ketamine, etomidate

Question 10

Characteristics oF IV

PROPOFOL

THIOPENTONE
- odd complications?

Ketamine

Etomidate - odd complications?

Answer 10

Rapid onset/non cumulative/hypotension = vasodilation, painful on injection

Rapid onset/offset due to redistribution/cumulative effect/ hypotension/slow metabolism/odd complications - porphyria, anaphylaxis, arterial spasm

Rapid onset/hypertension/powerful analgesic
Non-cumulative
Muscle rigidity
Unpleasant hallucinations

Cardio stability
Non-cumulative
Odd (major) complication - inhibits steroid synthesis, death from induced addisons

Question 11

Airway maintenance

Why is TI important

How are laryngeal reflexes overcome?

Answer 11

Optimum head position
Laryngeal mask
Tracheal intubation
- eliminates aspiration risk

Use muscle relaxant

Question 12

Side effects of muscle relaxants

Answer 12

Depolarising
Muscle pain 
Prolonged paralysis 
Histamine release
Hypotension 
Tachycardia

Question 13

Maintaining anaesthesia

Two methods and examples

Answer 13

Gaseous/volatile - nitrous oxide/isofluorane

IV - propofol

Question 14

Preoperative assessment

Reason?

Answer 14

Maximise patient safety

Toxic drugs with side effects

Question 15

Complications encountered during an op?

Answer 15

Patient

Anaesthesia
Surgeon

Question 16

Patient factors and examples

Answer 16

Pre-existing conditions

Cardio - AS, CAD

Resp - COPD, asthma

Diabetes - common//hypoglycaemic episodes

Question 17

Anaesthetic factors

Things to consider

Answer 17

Previous experiences

Past MH

• allergies
• medication
• renal impairment
• restrictive/obstructive lung diseases

Airway assessment

Question 18

Ways of reducing anaesthetic complications

Answer 18

Awareness
Anaphylaxis 
Hypoxia
Resp depression 
Aspiration 
Peripheral nerve damage

Question 19

Surgical considerations

Signs and tx of haemorrhage

Answer 19

Haemorrhage

• signs - falling BP//rising heart rate//suctioning blood
• tx - restore circulation with crystalloid