Anaesthetics

Question 1

Describe the ASA scoring system?

Answer 1

An assessment skill used to stratify risk for patients undergoing surgery
ASA 1: Normal, healthy patient
ASA 2: A patient with mild systemic disease (examples include smoker, well controlled daibetes/hypertension, pregnancy)
ASA 3: A patient with severe systemic disease (examples include COPD, morbid obesity, end stage renal failure with dialysis)
ASA 4: Severe systemic disease that is a constant threat to life (recent MI, severe valve dysfunction, end stage renal failure without dialysis)
ASA 5: A patient who is not expected to survivethe operation (ruptired AAA, massive trauma, multiple organ failure)
ASA 6: A brain dead patient whose organs are being harvested

Question 2

What are the rules on fasting prior to operations?

Answer 2

No food for 6 hours and no fluids for 2 hours prior to operation

Question 3

When should the COCP be stopped prior to major surgery?

Answer 3

4 weeks prior to major surgery (any operation lasting more than 30 minutes) or where there wil be immobilisation of the lower limbs until at least 2 weeks after surgery. If this is not possible then thromboprophylaxis with LMWH and graduation hoisery should be used.

Question 4

When would you use an LMA in surgery rather than an ET tube?

Answer 4

• Used in day surgery where paralysis is not required and there is a low risk of reflxu of gastric contents

Question 5

When is an ET tube used in surgery rather than an LMA?

Answer 5

Longer surgery
Risk of aspiration
Paralysis required

Question 6

What is malignant hyperthermia?

Answer 6

Condition seen following administration of anaesthetic agents and characterised by hyperpyrexia and muscle rigidity.
It is caused by excessive release of calciumf rom the sarcoplasmic reticulum of skeletal muscle.

Question 7

Which amaesthetic agent has anti emetic properties?

Answer 7

Propafol

Question 8

What is pseudocholinesterase deficiency?

Answer 8

also known as suximethonium apnea. This is a rare abnormality in the production of plasma cholinesterases whoch leads to an increased duration of action of muscle relaxants used. This will cause respiratory arrest and the patient has to be mechanically ventilated whilst waiting for musacle relaxants to degrade

Question 9

What is included in the WHO surgical safety checklist before the induction of anaesthesia?

Answer 9

1. Patient has confirmed site, identity, procedure and consent.
2. Site is marked
3. Anaesthetic safety check is complete
4. Pulse oximiter is on and functioning
5. Allergies
6. Is there a difficult airway or risk of aspiration
7. Is there a risk of more than 500ml blood loss.

Question 10

What are the three times when a surgical pause is done?

Answer 10

1. before anaesthesia
2. Before skin incision
3. Before the patient leaves the operating room

Question 11

List cannulas in order of size from smallest to largest with flow rates

Answer 11

Blue 22g: 33ml/min
Pink 20g: 54ml/min
green 18g: 80ml/min
Grey 16g: 180ml/min
Orange 14g: 270ml/min

Question 12

Which anaesthetic agent produces little myocardial depression and is therefor suitable for patients who are haemodynamically unstable?

Answer 12

Ketamine

Question 13

Which anaesthetic agent may cause a dissociative amnesia

Answer 13

Ketamine

Question 14

Which agent has a faster onset of action propafol or sodium thiopentone?

Answer 14

Sodium thiopentone

Question 15

Why is etomidate unsuitable for maintaining prolonged sedation?

Answer 15

causes adrenal suppression

Question 16

How long before surgery is warfarin stopped?

Answer 16

5 days.
The operation can go ahead when they INR is less than 1.5. Warfarin is then resumed at the normal dose on the evening of the surgery or the next day.