Anaesthesia

Question 1

What are the inhaled anaesthetics used for induction and maintenance of anaesthesia?

Answer 1

Volatile liquid anaesthetics (isoflurane, desflurane, sevoflurane)

Question 2

ADRs of Volatile liquid anaesthetics (isoflurane, desflurane, sevoflurane)

Answer 2

• Myocardial depression
• Malignant hyperthermia
• Halothane (not commonly used now) is hepatotoxic

Question 3

What are the inhaled anaesthetics used for maintenance of anaesthesia and analgesia?

Answer 3

Nitrous oxide

Question 4

ADRs of nitrous oxide

Answer 4

May diffuse into gas-filled body compartments → increase in pressure.
Should therefore be avoided in certain conditions e.g.pneumothorax

Question 5

What intravenous anaesthetics potentiates GABAA?

Answer 5

• Propofol
• Thiopental
• Etomidate

Question 6

When is Propfol used?

Answer 6

Very common induction agent for general anaesthesia and also used extensively in intensive care for ventilated patients

Has some anti-emetic effects - useful for patients with a high risk of post-operative vomiting

Question 7

ADRs of propofol

Answer 7

• Pain on injection (due to activation of the pain receptor TRPA1)
• Hypotension

Question 8

ADRs of Thiopental

Answer 8

Laryngospasm

Question 9

When is Etomidate used?

Answer 9

Causes less hypotension than propofol and thiopental during induction and is therefore often used in cases of haemodynamic instability

Question 10

ADRs of Etomidate

Answer 10

• Primary adrenal suppression (secondary to reversibly inhibiting 11β-hydroxylase)
• Myoclonus

Question 11

When is ketamine used?

Answer 11

• Acts as a dissociative anaesthetic.
• Doesn’t cause a drop in blood pressure so useful in trauma

Question 12

ADRs of Ketamine

Answer 12

• Disorientation
• Hallucinations

Question 13

What are the rules for oral fluids before surgery

Answer 13

Oral fluids:
- patients having surgery may drink clear fluids until 2 hours before their operation
- drinking clear fluids before the operation can help reduce headaches, nausea and vomiting afterwards
- clear fluids are water, fruit juice without pulp, coffee or tea without milk and ice lollies

Patients are generally advised to fast from non-clear liquids/food for at least 6 hours before surgery.

Question 14

What are the symptoms of postoperative ileus?

Answer 14

Abdo pain
Bloating
Vomiting

Following bowel surgery

Question 15

Tx of postoperative ileus

Answer 15

nil-by-mouth initially, may progress to small sips of clear fluids

Nasogastric tube if vomiting

IV flud is to maintain normovolaemia- additives to correct any electrolyte disturbances

total parenteral nutrition- occasionally required for prolonged/severe cases

Question 16

What is the contraindication for Laryngeal mask?

Answer 16

Provides poor control against reflux of gastric contents therefore is unsuitable in non fasted patients

Question 17

When should women stop their COCP/HRT before surgery?

Answer 17

4 weeks before surgery

Question 18

What is required prior to surgery for patients taking prednisolone?

Answer 18

Hydrocortisone supplementation

Question 19

Tx of confirmed anastomotic leak

Answer 19

This is a surgical emergency and the patient must return to theatre as soon as possible

Question 20

How should Total parenteral nutrition be administered?

Answer 20

via a central vein as it is strongly phlebitic

Question 21

When might an ECG be done as part of their pre-operative assessment?

Answer 21

• Patients over the age of 65 may need an ECG before major surgery.
• Patients with renal disease may need a full blood count and an ECG depending on their ASA grade even before intermediate surgery.
• Patients with diabetes may need an ECG before intermediate surgery.

Question 22

Who will usually require a variable rate intravenous insulin infusion (VRIII)

Answer 22

patients on insulin who are either undergoing major procedures (surgery requiring a long fasting period of more than one missed meal) or whose diabetes is poorly controlled

Question 23

How should patients with oral anti-diabetic drugs be managed before surgery?

Answer 23

most patients taking only oral antidiabetic drugs may be managed by manipulating medication on the day of surgery, depending on the particular drug

Question 24

Early causes of post-op pyrexia (0-5 days)

Answer 24

• Blood transfusion
• Cellulitis
• Urinary tract infection
• Physiological systemic inflammatory reaction (usually within a day following the operation)
• Pulmonary atelectasis - this if often listed but the evidence base to support this link is limited

Question 25

Late causes of post-op pyrexia (>5 days)

Answer 25

• Venous thromboembolism
• Pneumonia
• Wound infection
• Anastomotic leak

Question 26

What should be done to once-daily insulin dose on the day before and the day of surgery?

Answer 26

once-daily insulin dose should generally be reduced by 20% on the day before and the day of surgery

Question 27

What to do with metformin on the day of the surgery?

Answer 27

Surgery / metformin on day of surgery:
OD or BD: take as normal
TDS: miss lunchtime dose
assumes only one meal will be missed during surgery, eGFR > 60 and no contrast during procedur

Question 28

Tx of Local anesthetic toxicity

Answer 28

IV 20% lipid emulsion

Question 29

Side effect of suxamethonium and tx

Answer 29

Malignant hyperthermia is a recognised serious side effect of suxamethonium among those who are susceptible and requires IV dantrolene therapy

Question 30

Maintenance fluids for adult

Answer 30

25-30 ml/kg/day of water