Anaesthetics

Question 1

anaesthetics are either delivered…

Answer 1

IV or inhalational

Question 2

what anaesthetics are the fastest in inducing anaesthesia?

Answer 2

propofol and etomidate ~ 30 secs

Question 3

what is unique about propofol as an induction anaesthetic?

Answer 3

Of the available induction agents, propofol has a unique ability to suppress airway reflexes and to produce apnea

Question 4

How might we clarify correct airway placement of the endotracheal tube?

Answer 4

• Effective manual ventilation.
  ●Symmetrical chest rise.
  ●Visible condensation in mask or tube of airway device.
  ●End-tidal CO2 waveform on gas analyzer.
  ●If endotracheal tube placed, right mainstem bronchus intubation and esophageal intubation must be ruled out with bilateral breath sounds and lack of sounds of air entry into stomach, and CO2 wave form detection. Especially in thin patients, air entry into the stomach may be heard in the chest and mistaken for breath sounds.
  ●If a SGA is used, air leak should occur at high enough peak pressure to allow adequate tidal volume, 18 to 20 cm H2O.

Question 5

another name for suxamethonium?

Answer 5

succinylcholine

Question 6

3 stages of anaesthesia

Answer 6

1. Induction
2. Maintenance
3. Reversal

Question 7

what are the 2 forms of GA?

Answer 7

1. Spontaneous ventilation (Laryngeal mask airway- supraglottis airway)
2. Assisted ventilation with NM blocking agent (endotracheal tube)

Question 8

what are the 3 types of anaesthesia?

Answer 8

1. General Anaesthesia
2. Regional anaesthesia
3. Local anaesthesia

Question 9

what are 2 forms of regional anaesthesia?

Answer 9

Epidural

Spinal

Question 10

when would we consider Assisted ventilation with NM blocking agent and ETT for GA?

Answer 10

Would use assisted ventilation for Neurosurgery, Major cavity surgery, Long surgery and for special anaesthetic indications such as:
	• Non fasting- trauma
	• GORD
	• Pregnancy > 20 weeks 
	• Obesity
	• OSA
etc

Question 11

complications of anaesthesia?

Answer 11

• Allergy/anaphylaxis
	• Malignant hypertension
	• Risk of respiratory depression
	• Aspiration risk
	• Damage to spinal nerve (regional)
	• BLEEDING
	• INFECTION
\+ PONV

Question 12

where is a spinal anaesthesia injected?

Answer 12

Injected into the Subarachnoid space below L1-L2

Question 13

what drugs can we use for induction of anaesthesia with spontaneous ventilation?

Answer 13

IV Midazolam
IV Fentanyl
IV Propofol ( the main one)

Or Etomidate

Question 14

what neuromuscular blocking drugs are there?

Answer 14

Recuronium
/Veccuronium
/atrecurium

Question 15

describe the procedure of induction of anaesthesia?

Answer 15

1. Place oxygen mask on patient
2. Ask the patient to take nice deep breaths to fill lungs with oxygen. = PRE-OXYGENATION
3. If spontaneous ventilation- laryngeal mask airway- insert and inflate. Attach mask to it.
   OR
4. NM blockers= AcH R competitive antagonists. Non depolarising. If used, must ventilate the patient with endotracheal tube!!
5. Intubate with laryngoscope and inflate ETT. Attach mask to it
6. Listen to the left hand side bc most likely go down R main bronchus.
7. Check CO2 levels

Question 16

what inhaled drug do we use during maintenance of anaesthesia?

Answer 16

sevoflurane

Question 17

what other adjunct drugs do we use during maintenance of anaesthesia?

Answer 17

oxygen

morphine IV

Question 18

what do we do when we reverse anaesthesia?

Answer 18

1. Turn off all anaesthetics running
2. Turn the oxygen up to 100%
3. Maintain analgesia
4. If used NM block need neostigmine, which is acetylcholinesterase inhibitor. + atropine (antimuscarinic)
5. SLUD effects and bradycardia

Extubate- deflate endotracheal tube

Question 19

Tell me about ketamine

Answer 19

Dissociative anaesthetic drug
Commony used in developing countries
Causes hypersalivation
Doesn’t ablate reflexes so hard to intubate

Question 20

what drugs do we use to reverse NM blocking drugs?

Answer 20

Neostigmine
Atropine
Glycopyrolate
Sugammadex

Question 21

what drugs in particular do sugammadex reverse?

Answer 21

rocuronium and vercuronium

Question 22

define MAC for inhaled anaesthetics

Answer 22

Each agent has a specific minimum alveolar concentration (MAC), defined as the amount of vapour (%) needed to render 50% of spontaneously breathing patients unresponsive to a standard painful surgical stimulus. MAC is inversely proportional to potency.

Question 23

Why dont we use desflurane for induction anaesthesia?

Answer 23

causes respiratory and salivary secretions

Question 24

what type of allergy do we need to worry about with propofol anaesthetic?

Answer 24

egg allergy as propofol emulsion contains egg

Question 25

is thiopental suitable for maintenance anaesthesia?

Answer 25

no. it has zero order kinetics and rather slow metabolism

Question 26

what kind of drug is thiopental?

Answer 26

thiobarbituate anaesthetic drug

Question 27

adverse effects and contraindications for thiopental?

Answer 27

hangover effect, histamine release--> inflammation and contraindicated in porphyria

Question 28

what are the two groups of local anaesthetics?

Answer 28

amine and esters

Question 29

which form of local anaesthetic- charged or uncharged, can pass the cell membrane?

Answer 29

uncharged

Question 30

what is the molecular target for action of local anaesthetics?

Answer 30

blocks sodium channels

Question 31

tell me about suxamethonium?

Answer 31

suxamethonium is a depolarising neuromuscular blocking drug, that binds to AcH receptors on post synaptic membrane and prevents AcH from binding. Is metabolised by cholinesterase. Very fast acting.

Question 32

SE of suxamethonium?

Answer 32

``` Malignant hyperthermia apnea anaphylaxis hyperkalemia increased intraocular pressure myalgia bradycardia histamine release ```

Question 33

how do non depolarising neuromuscular blockers work?

Answer 33

they reversibly competitively antagonise Ach receptor

Question 34

what are the two types of non depolarising neuromuscular blockers?

Answer 34

aminosteroids and benzylisoquinoliniums

Question 35

where does neostigmine act?

Answer 35

acts on both muscarinic and nicotinic receptors hence SLUD effects

Question 36

what is neostigmine always administered with?

Answer 36

atropine or glycopyrolate to reduce SLUD effects

Question 37

how do we assess neuromuscular activity during general anaesthesia using muscle relaxant?

Answer 37

apply charge to ulnar nerve and look for T1 movement. TOF

Question 38

what kind of drug is metaraminol? why is it used in anaesthetics

Answer 38

metaraminol is an alpha 1 agonist that mediates peripheral vasoconstriction. used for hypotension