sedation - muscle relaxants

Question 1

Name 2 non depolarising agents?

Answer 1

1. atacurium 2. panacuronium

Question 2

Name 1 depolarising agent?

Answer 2

Suxamethonium

Question 3

When should Suxamethonium be avoided?

Answer 3

Head injuries as it increases ICP

Question 4

How are muscle relaxants reversed?

Answer 4

anticholinesterases - increase Ach available e.g. Neostigmine etc

Question 5

Symptoms of malignant hyperthermia?

Answer 5

1. tachycardia 2. tachypnea 3. acidosis

Question 6

Mx of malignant hyperthermia?

Answer 6

1. stop anaesthetic trigger 2. hyperventilate - 100% high flow O2 3. rapidly administer Dantrolene 2.5mg/kg 4. administer sodium bicarbonate for metabolic acidosis/hyperkalemia

Question 7

Explain the process of how an action potential is propogated?

Answer 7

1. Presynaptic motor nerve

( Acetyl CoA + Choline –> ACh)

via Cholineacetyl transferase

2. ACh in capsule
3. Ca 2+ released
4. ACh is released into the synaptic cleft
5. ACh bind to ACh receptor on post synaptic cleft
6. Opening of voltage Na+ - propogation of action potential
7. Acetlycholine esterase enzyme breaks up and recycles ACh

Question 8

What are the main categories of muscle relaxants?

Answer 8

1. Depolarizing
2. Non-depolarizing
   - Aminosteroidal
   - Benzyliso-quin

Question 9

what is the main depolarising muscle relaxant called?

Answer 9

Suxamethonium

Question 10

What is the mechanism of action of Suzamethonium?

Answer 10

1. intially acts as an agonist - binds to ACh receptor and depolarises the muscle membrane –> fasiculations
2. antagonises ACh at its receptor –> inactivating sodium voltage gated channels

Question 11

What is sux used for?

Answer 11

very fast onset of action 26 minutes - used in emergency settings

Question 12

What are the main effects of Suxamethonium?

Answer 12

(initial agonist of acetylecholine- thus parasympathetic effects)

1. Airway - loss of airway relexes
2. Breathing - Apnea
3. CVS - bradycardia
4. Disability - paralysis

E - muscle pain ( as a result of fasiciluations)

Fluid/renal - Hyperkalaemia

Question 13

What is the mechanism of action of acetylcholine esterase inhibitors?

Answer 13

1. class of drug - acetylecholine esterase inhibitors - act as reversal agents for muscle relaxants
2. moa - increases the molecules of acetyl coA thus muscle cells more likely to depolarise

Question 14

What is the most commonly used reversal agent called?

Answer 14

Neostigmine

Question 15

What are the main side effects of acetylcholinesterase inhibitors?

Answer 15

clinically the effect is excess acetylcholine

1. Airway - increased salivation
2. Breathing - increased secretion/bronchocontriction
3. CVS - bradycardia
4. Disability - pupil meiosis
5. E - increased gut motility /secretions

Question 16

Which muscle relaxant has immediate reversal agent and what is it called?

Answer 16

1. Muscle relaxant - Recuronium
2. Reversal agent - Sugammadex -

Question 17

suxamthonium

Answer 17

1. muscle relaxant for rapid sequence induction for intubation
2. causes hyperkalaemia
3. CI - suxamethonium is contraindicated for patients with penetrating eye injuries or acute narrow angle glaucoma