L06 Neuromuscular blocking agent

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  1. What is 'Balanced Anesthesia'?
    • Hypnosis (unconsciousness)
    • Analgesia (pain relief)
    • Paralysis (relaxation)
  2. Why do we need NMB?
    • no movement for delicate microscopic surgery
    • decrease muscle tone for easier retraction of body wall allowing room for surgery
  3. When NMB is used, what else should be provided for the patient?
    intra-tracheal intubation for mechanical ventilation as respiratory muscle is also paralysed
  4. Give one example of Depolarising NMB.
  5. Pharmacokinetics of Succinylcholine
    e.g. Onset time, Offset time, Metabolism
    • Onest time: 60 seconds (very rapid)
    • Offset time: 10-15 mins (rapid)
    • Metabolism: butyrylcholinesterase (plasma cholinesterase, pseudocholinesterase)
  6. What should be expected if the patient receiving succinylcholine does not retain motion power after 10-15 mins?
    Atypical pseudocholinesterase (very rare genetic trait)
  7. Name 4 adverse effects of succinylcholine.
    • Arrhythmias
    • Sinus Bradycardia
    • Hyperkalemia (binding to extra-junctional receptors in muscle -> transient K+ release -> possible death)
    • Phase II neuromuscular block
  8. Why there are severe adverse effects of succinylcholine?
    Succinylcholine binds to ACh receptors in teh ANS -> affecting both the sympathetic and asympathetic nervous output
  9. Name 5 non-depolarizing NMBs.
    • Mivacurium (Short-acting)
    • Atracurium (Intermediate-acting)
    • Cis- Atracurium (Intermediate-acting)
    • Rocuronium (Intermediate-acting)
    • Pancuronium (Long-acting)
  10. Pharmacokinetics of Mivacurium
    e.g. duration of action, onset, metabolism
    • Duration of Action: 5-10 mins (short-acting)
    • Onset: not rapid
    • Metabolism: esterase (which is abundant in body leading to rapid elimination and short duration of action)
  11. Pharmacokinetics of Atracurium
    e.g. duration of action, metabolism
    • Duration of Action: 20-30 mins (intermediate-acting)
    • Metabolism: Hofmann elimination (not enzymatic but depends on temperature and pH -> good for storage as in low temp and low pH there will be no metabolism) -> high confidence in retaining the motion power regardless of the liver function of the patient
    • most popular NMB
  12. Why long-acting NMB is not preferred?
    Giving Short-eacitng drugs continuously gives higher degree of flexibility
  13. 2 Mechanisms for terminating NMB effect
    • Metabolism and elimination of NMB
    • Acetylcholinesterase inhibition (anticholinesterase)
  14. 2 Types of drugs for terminating NMB actions
    • anticholinesterase
    • chelating agent (suck out the drugs physically -> still under research)
  15. Examples and Mechanism of Anticholinesterase
    • Examples: Neostigmine and pyridostigmine
    • Mechanism: decrease action of cholinesterase -> increase concentration of acetylcholine -> reverse competitive inhibition
  16. Why there is a high incidence of pre-operative anaphylaxis of NMB?
    • all NMB are quaternary ammonium compounds
    • nowadays most cosmetics include quaternary ammonium compounds -> exposure again -> anaphylaxis
  17. Which muscle is used for neuromuscular monitoring?
    Adductor Pollicis Muscle
Card Set:
L06 Neuromuscular blocking agent
2013-10-20 06:48:57

MSS Pharmacology
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