Anaesthetics

Question 1

Types of anaesthesia

Answer 1

General anaesthesia- total loss of sensation
Regional anaesthesia- loss of sensation to a region or part of the body
Local anaesthesia- Topical, infiltration

Question 2

Components of general anaesthesia

Answer 2

Amnesia- unconsciousness
Analgesia
Akinesis- immobilisation

Question 3

What happens during GA

Answer 3

Monitoring
IV access
Start the process- induction of anaesthesia, analgesia and muscle relaxation
Maintenance

Question 4

Monitoring in GA

Answer 4

ECG
SP02
NIPB
Airway gases- oxygen, CO2 and vapour
Airway pressure
Nerve stimulator- if a muscle relaxant is used
Temperature monitoring- temp should be 37 before surgery

Question 5

Next step after monitoring

Answer 5

IV access

Attached to fluids

Question 6

Start the process of GA

Answer 6

Drugs- amnesia- induction agents

Question 7

Induction agents

Answer 7

Propofol
Thiopentone
Ketamine
Etomidate

Question 8

Propofol

Answer 8

Most commonly used
Dose- 1.5-2.5 mg/kg
Lipid based
Excellent suppression of airway reflexes
Decreases incidence of PONV- post-op nausea and vomiting

Question 9

Unwanted effects of propofol

Answer 9

Marked drop in HR and BP
Pain on injection
Involuntary movements

Question 10

Thiopentone

Answer 10

Barbiturate
Dose- 4-5 mg/kg
Faster than propofol
Used mainly for rapid sequence induction- (when induction is required quickly to prevent aspiration)
Antiepileptic properties and cerebral protective

Question 11

Unwanted effects of thiopentone

Answer 11

Fall in bp but rise in hr
Rash/bronchospasm
Intra-arterial injection- thrombosis and gangrene
contraindicated in porphyria

Question 12

Ketamine

Answer 12

Dissociative anaesthesia- anterograde amnesia and profound analgesia
Used for sole anaesthetic for short procedures- pulling of wires, burn dressing change
Dose- 1-1.5 mg/kg
Slow onset (90 secs)
Rise in HR/BP, bronchodilation
In a patient with heart failure

Question 13

Unwanted side effects of ketamine

Answer 13

Nausea and vomiting

Emergence phenomenon

Question 14

Etomidate

Answer 14

rapid onset
Dose- 0.3 mg/kg
haemodynamic stability
lowest incidence of hypersensitivity reaction

Question 15

Unwanted side effects

Answer 15

Pain on injection
Spontaneous movements
Adreno-cortical suppression
High incidence PONV

Question 16

Routes of anaesthesia

Answer 16

Total IV anaesthesia

Inhalational anaesthesia

Question 17

MAC

Answer 17

Concentration of the vapour

That prevents the reaction to a standard surgical stimulus in 50% of subjects

Question 18

Inhalational agents

Answer 18

sevoflurane
Desflurane
Isoflurane

Question 19

sevoflurane

Answer 19

sweet smelling

inhalational induction

Question 20

sevoflurane

Answer 20

Sweet smelling
inhalational induction
USE- Chubby child

Question 21

Isoflurane

Answer 21

Least effect on organ blood flow

Question 22

Isoflurane

Answer 22

Least effect on organ blood flow

Use- organ retrieval from a donor

Question 23

Non depolarising muscle relaxants

Answer 23

Block the nicotinic receptors
Examples- mivacurium (15-30mins), vecuronium, pancuronium (60 minutes)
Reversal with neostigmine and glycopyrrolate

Question 24

Depolarising muscle relaxants

Answer 24

Prevent breakdown of acetlycholinesterase

Example- suxamethonium (dose 1-1.5 mg/kg)

Question 25

To treat hypotension- Inotropes

Answer 25

Ephedrine- increases BP and HR Phenylepherine- Increases BP and lowers HR Metaraminol- Increases BP and lowers HR

Question 26

Anti emetics for PONV

Answer 26

``` Ondansetron- most common- given half an hour before the end of operation Cyclizine Dexamethasone- given at induction Prochlorperazine Metoclopramide ```

Question 27

reversal

Answer 27

Stop anaesthetic vapours Give oxygen Perform throat suction Reverse muscle relaxation with neostigmine and glycopyrrate (blocks nicotinic receptors in the heart so acetylcholine can only work in the muscles)

Question 28

Post anaesthetic care

Answer 28

Administer o2 during transfer Handover the patient- brief history, any problems anticipated, intraoperative, analgesia and PONV prophylaxis Prescribe- rescue analgesia, rescue antiemetics, fluids

Question 29

Aims of pre-operative assessment

Answer 29

Allay fear and anxiety Identify potential anaesthetic difficulties and medical conditions Improve safety by assessing and quantifying risk Optimise and plan of the peri-operative care Provide an opportunity for explanation and discussion (consent)

Question 30

Mallampati score

Answer 30

``` To check for ease of intubation Class I-IV- class 1 being the easiest ```

Question 31

ASA Grading

Answer 31

Physical status examination for assessing fitness for surgery Grades 1-6 For emergency cases the suffix 'E' is used

Question 32

ASA Grades

Answer 32

Grade 1- Fit and healthy Grade 2- Mild systemic disease Grade 3- Severe systemic disease with substantial functional limitations Grade 4- severe systemic disease with a constant threat to life Grade 5- Moribund patient who is not expected to survive with or without operation Grade 6- Brain stem patient whose organs are being removed for donor purposes

Question 33

Grades of surgery

Answer 33

Minor- excision skin lesion Intermediate- inguinal hernia Major or complex- hysterectomy

Question 34

NCEPOD classification of surgery

Answer 34

Immediate- resus simultaneous with intervention within minutes Urgent-time available for resus within hours Expedited-patient requiring early treatment where the condition is not an immediate threat to life or limb within days Elective- 18 weeks initiative

Question 35

Intralipid

Answer 35

reduces concentration of free local anaesthetic by absorbing it up from the blood