Anaesthesia

Question 1

What are the three stages of anaesthesia?

Answer 1

Induction, Maintenance, and Reversal.

Question 2

Why is balanced anaesthesia used?

Answer 2

Because no single drug provides all desired effects (analgesia, unconsciousness, muscle relaxation).

Question 3

What drugs are used for pain relief in anaesthesia?

Answer 3

Opioids and regional anaesthetics.

Question 4

What are neuromuscular blocking agents used for?

Answer 4

Muscle relaxation and to prevent patient movement.

Question 5

Name four IV induction agents.

Answer 5

Propofol, Thiopentone, Etomidate, Ketamine.

Question 6

What are the characteristics of an ideal IV induction agent?

Answer 6

Rapid onset and recovery, minimal side effects, no injection pain, non-toxic.

Question 7

What are the indications for using Propofol?

Answer 7

TIVA, conscious sedation, asthma, history of PONV or malignant hyperthermia.

Question 8

What are the adult and elderly induction doses for Propofol?

Answer 8

Adults: 2–2.5 mg/kg; Elderly: 1–1.5 mg/kg.

Question 9

What are precautions for Propofol use?

Answer 9

Use with caution in elderly, cardiac failure, hypovolaemia, fixed cardiac output.

Question 10

What is the pH of Thiopentone solution?

Answer 10

pH 10.5.

Question 11

What is an absolute contraindication to Thiopentone?

Answer 11

Porphyria.

Question 12

What is the induction dose for Etomidate?

Answer 12

0.2–0.3 mg/kg.

Question 13

Why is Etomidate not used for continuous infusions?

Answer 13

It causes adrenocortical suppression.

Question 14

What are the IV and IM induction doses for Ketamine?

Answer 14

IV: 1–2 mg/kg; IM: 5–10 mg/kg.

Question 15

Name three key contraindications to Ketamine.

Answer 15

IHD, ↑ ICP, psychiatric illness.

Question 16

What are the uses of Ketamine?

Answer 16

Sick patients, burns, short procedures, analgesia, status asthmaticus.

Question 17

Name four benzodiazepines used in anaesthesia.

Answer 17

Lorazepam, Temazepam, Diazepam, Midazolam.

Question 18

What is the dose range for oral premedication with Midazolam in adults?

Answer 18

7.5–15 mg orally.

Question 19

What drug reverses benzodiazepine effects?

Answer 19

Flumazenil.

Question 20

What are the three classes of volatile agents?

Answer 20

Halogenated hydrocarbons, halogenated ethers, and non-halogenated gases.

Question 21

What is MAC (Minimum Alveolar Concentration)?

Answer 21

The alveolar concentration needed to prevent movement in 50% of subjects in response to pain

Question 22

Name three factors that decrease MAC.

Answer 22

Increasing age, hypothermia, opioids.

Question 23

Name two non-halogenated volatile agents.

Answer 23

Nitrous oxide, xenon.

Question 24

What is the MAC of Sevoflurane?

Answer 24

1.80%.

Question 25

Why is Sevoflurane preferred for induction in children?

Answer 25

It is non-irritant and has a sweet smell.

Question 26

What toxic compound can Sevoflurane produce with CO₂ absorbents?

Answer 26

Compound A.

Question 27

What causes diffusion hypoxia after N₂O administration?

Answer 27

Rapid diffusion of N₂O into alveoli reduces oxygen levels.

Question 28

How is diffusion hypoxia prevented?

Answer 28

Administer 100% oxygen after stopping N₂O.

Question 29

What is the mechanism of action of opioids in anaesthesia?

Answer 29

They act on μ-opioid receptors to block pain transmission.

Question 30

What is a key property of Fentanyl?

Answer 30

Ultra-short acting, context-sensitive half-life ~4 min.

Question 31

Name a depolarizing muscle relaxant.

Answer 31

Succinylcholine.

Question 32

Name a short-acting non-depolarizing muscle relaxant.

Answer 32

Mivacurium.

Question 33

Where do non-depolarizing muscle relaxants act?

Answer 33

Nicotinic acetylcholine receptors at the neuromuscular junction.

Question 34

Give two examples of ester local anaesthetics.

Answer 34

Benzocaine, Procaine.

Question 35

Give two examples of amide local anaesthetics.

Answer 35

Bupivacaine, Lidocaine.

Question 36

What determines the potency of a local anaesthetic?

Answer 36

Lipid solubility.

Question 37

How are ester local anaesthetics cleared from the body?

Answer 37

Hydrolysis by cholinesterases.

Question 38

What are the main uses of local anaesthetics?

Answer 38

Nerve blocks, IV regional anaesthesia, epidurals, and spinal anaesthesia.