non-depolarizing NMB.txt

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non-depolarizing NMB.txt
2014-02-02 19:58:37
non depolarizing
non depolarizing
non depolarinz
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  1. MOA of non depolarizers
    • act competitively with Ach at the alpha sub units of the post junctional nAChRs without causing a change in the configuration of these receptors.
    • -may also block ion receptor channels
    • -act on pre and post junctional receptors but post junctional are more important
  2. neuromuscular transmission fails with ____-___% of the receptors are blocked
    • 80-90%
    • -occupation of as many as 70% of the nAChRs by a NMBD does not produce evidence of neuromuscular blockade as reflected by the twitch response
    • -wide safety margin on these drugs
  3. Do you have skeletal muscle fasiculations with non-depolarizing NMB
  4. characteristics of skeletal muscle response in presence of non depolarizing NMB
    • -decreased twitch response to a single stimulus
    • -unsustained response during continuous stimulation
    • -TOF ration of <0.7
    • enhance of other non dep NMD
    • antagonism by anticholinesterase drugs
  5. skeletal muscle contraction is a
    • all or none response
    • -so when twitch response is decreased some fibers are contracting normally and some are completely blocked
  6. autonomic safety margin
    the difference between the dose of NMBD that produces NM blockade and circulatory effects
  7. Which drug has a narrow margin of saftey
    ED95 of pancuronium produces NM blockade and circulatory effects
  8. pateints with asthma or acutely injured patients with multiple organ system failure that require skeletal muscle paralysis for mechanical ventilation for prolonged periods are prone to what
    • skeletal muscle weakness on recovery that may last for weeks to months.
    • -moderate-severe quadriparesis, but usually maintain normal sensory function
    • -more common in aminosteroid drugs such as pancuronium, vecuronium, Rocuronium
  9. What can enhance effects of nondep NMBDs
    • VA
    • aminoglycoside antibiotics
    • local anesthetics- small doses enhance, large can block
    • cardiac antidysrhythmic-lidocaine  
    • diuretics-Lasix small doses enhance, large antagonize
    • mag
    • lithium
    • gender
  10. patient on anticonvulsant drugs are
    • resistant to some but not all non-dep NMBD
    • -these patients will recover more quickly from NM blockade
  11. combo of corticosteroids and NMBDs as little as 96 hours can cause
    severe muscle weakness  that may last weeks or months.
  12. hypokalemia  ______ depolarizer and _____ non depolarizer

    hyperkalemia _______ depolarizer and ______ non depolarizer
    • decrease and increase
    • increase and decrease
  13. TRue or false
    females have a greater incidence of allergic reactions to NMBD than males
  14. Pancuronium
    most commonly administered long acting NMB b/c of low cost
  15. pancuronium supplied
    1-2 mg/ml
  16. induction of pancuronium
    0.04-0.1 mg/kg
  17. onset of pancuronium
    1-3 minutes
  18. duration of pancuronium
    40-60 minutes
  19. Pancuronium causes _____ heart rate
    • increased - typically 10-15 % increase in HR, MAP and CO
    • -no histamine release
  20. majority of pancuronium cleared
    • renally
    • aging decreases clearance b/c of renal function
    • -but patients with total biliary obstruction have increased VD decreased plasma clearance, and prolonged elimination of this drug
  21. What is a good alternative to SCh when rapid onset of blockade is needed
    • rocuronium
    • laryngeal muscles are more resistant to the effects of ROC than is the adductor pollicis, means that a larger dose of ROC will resemble SCh at the adductor pollicis but will be delayed when compared to that of SCh at the laryngeal muscles
  22. Intermediate acting non depolarizers and clearance
    these drugs produce efficient clearance mechanisms that minimize the likelihood of significant cumulative effects with repeated injections or continous infusion
  23. priming principle
    • based on the concept that onset of blockade is in 2 steps.
    • 1- initial binding of spare receptors with no clinical effect and subsequent deepening of the blockade
    • Tx first with small subparalyzing dose followed in about 4 minutes with larger dose
    • -initial subparalyzing dose decreases the safety margin
    • -works best when administration of SCh is best avoided but rapid onset of blockade is needed.
  24. atracurium supplied
    10 mg/ml
  25. atracurium induction
    0.3-0.5 mg/kg
  26. atracurium onset
    2 minutes
  27. atracurium duration
    20-35 minutes
  28. the way I remember histamine release is SAM
    • SCh
    • atracurium
    • mivacurium- short acting and we don't use
  29. atracurium does have moderate histamine release
    can cause facial and truncal flushing
  30. atracurium eliminated by
    • Hoffman elimination
    • -account for lack of cumulative effects with repeated doses or continuous infusion
  31. atracurium should not be used with drugs with
    alkaline ph- may prematurely break down drug
  32. what is major metabolite of atracurium
    • laudanosine
    • -not active at NMJ but may cause CNS stimulation in very high concentrations
    • -excretion of this metabolite is altered with biliary obstruction b/c accounts for 70% of excretion
  33. effective doses of atracurium are the same in young and old because of elimination the only consideration is in infants (0-6 mo) and they require only
    half the dose
  34. Vecuronium supplied
  35. vecuronium induction
    0.1 mg/kg
  36. vecuronium  onset
    3 minutes
  37. vecuronium duration
    • 30-60 minutes
    • -intermediate  acting
  38. vec is unstable in solution so it is supplied
    as a lyophilized powder that must be dissolved in sterile water before use
  39. clearance of vec
    • hepatic and renal
    • -elimination half time prolonged in patients with renal failure even though hepatic metabolism is the biggest factor
  40. pts with hepatic cirrhosis and vec
    prolonged elimination half time and prolonged duration of action
  41. hypercarbia will enhance vec so be careful in post op
    hypoventilation in post op could enhance NM blockade
  42. onset of action of vec is more ____ in infants than in adults and the duration of action is _____ in infants and ______ in children
    • rapid
    • longest-because of immature liver enzymes
    • shortest
  43. Rocuronium supplied
    10 mg/ml
  44. Rocuronium induction
    0.6-1.0 mg/kg
  45. Rocuronium onset
    60 seconds
  46. Rocuronium duration
    • 30-120 minutes
    • -intermediate acting
  47. laryngeal muscle is resistant to ROC so you have to use larger doses be careful if you are not sure if laryngeal muscle paralyzed because this could lead to
  48. ROC duration of action prolonged in patients that are
    morbidly obese
  49. ROC and clearance
    • renal and hepatic
    • -renal failure may produce increased duration of action
    • -liver disease increases the Vd  and could result in longer duration of the drug esp with repeated doses or cont infusion
  50. Cisatracurium supplied
    2 mg/ml
  51. Cisatracurium induction
    0.1-0.2 mg/kg
  52. Cisatracurium onset
    2 minutes
  53. Cisatracurium duration of action
    30-60 minutes
  54. Cisatracurium elimination
    • Hoffman elimination=77%
    • renal =16%
    • -can be administered to patients with renal and hepatic dysfunction without change in NM blocking profile
    • -absence of cumulative effect even with repeated doses or continuous  infusion