Special Techniques

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Special Techniques
2012-04-21 23:47:03
Clinical Practice

Clinical Practice
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  1. What is local analgesia?
    temporary loss of pain sensation and movement
  2. What does local analgesia affect?
    local neurons
  3. Does local analgesia affect the entire CNS?
  4. Does local analgesia have any of the same risks as general anesthesia?
  5. Local analgesia is _____ toxicity and _____ cost.
    • low
    • low
  6. What kind of recovery does local analgesia have?
  7. Why is local analgesia good for Caesarian sections?
    because it does not cross the placenta and affect the babies
  8. What are the disadvantages of local analgesia?
    • still need restraint
    • can OD small patients
    • does not work well on connective tissue
  9. What are the different types of local analgesia?
    • lidocaine
    • bupivacaine
    • procaine
    • tetracaine
    • mepivacaine
    • cocaine
  10. What is lidocaine?
  11. What is the onset of lidocaine?
    almost immediate
  12. What is the duration of lidocaine?
    1 - 2 hours
  13. What does lidocaine feel like to the patient when it is injected?
    it stings
  14. What is bupivacaine?
  15. What is the onset time for bupivacaine?
    20 minutes
  16. What is the duration of bupivacaine?
    6 hours
  17. Is epinephrine a local analgesia?
  18. what is epinephrine?
    a sympathetic neurotransmitter
  19. What does epinephrine do?
  20. What drug do we sometimes add epinephrine too and why?
    • lidocaine
    • the vasoconstriction keeps the drug from being picked up into circulation
  21. What are the advantages of using epinephrine?
    • prolongs numbing effect
    • reduces toxicity by lowering blood concentration
    • reduces bleeding at surgery site due to vasoconstriction
  22. What are the disadvantages to using epinephrine?
    may reduce healing rate at surgery site
  23. What are the systemic effects of epinephrine?
    increased HR, strength of contraction, more prone to arrhythmias
  24. When would we use lidocaine without epinephrine?
    treat certain cardiac arrhythmias
  25. Does local analgesia have little to no respiratory or cardiovascular side effects?
  26. Does local analgesia provide any sedation?
  27. What does local analegsia do?
    blocks transmission of nerve impulses (stops nerve depolarization)
  28. What is the order of loss of sensation?
    • pain
    • cold
    • warmth
    • touch
    • joint sensation
    • deep pressure
  29. What is sympathetic blockage?
    loss of autonomic impulses from brain to body
  30. What does sympathetic blockage mainly affect? Why?
    • sympathetic nervous system
    • due to location of nerve cell bodies in sympathetic ganglia
  31. Where are the sympathetic ganglia located?
    on either side of the thoracic and lumbar vertebrae
  32. What does sympathetic blockage cause?
    • bradycardia
    • vasodilation
    • hypotension
  33. What could happen during an epidural?
    agent may go too far cranial and affect the sympathetic ganglia
  34. What are the different routes of administering local analgesias?
    • topical
    • inflitration (injecting into the area)
    • regional
    • intravenous
  35. Do local analgesia's penetrate intact skin?
  36. What do local analgesia's penetrate?
    mucous membranes
  37. What are the different types of topical analgesias?
    • conjunctiva (eye drops)
    • oral (spray for vocal cords)
    • lubricating gels
  38. How do we avoid complications with infiltrating a local analgesia?
    • clip and prep to avoid infection
    • use small needle to avoid tissue damage
  39. What are the two different types of infiltration?
    • nerve blocks
    • line blocks
  40. When do we mainly use nerve blocks?
    in large animals
  41. How do we deposit local analgesia for nerve blocks?
    around the nerve - not in it
  42. Where do we put line blocks?
    infiltrate in line between spinal cord and surgery site
  43. What is the onet of a line block?
    3 - 5 minutes
  44. When are regional analgesia mainly used?
    human and large animal medicine
  45. What is the injection site for regional analgesia?
    into major nerve plexus or close to spinal cord
  46. What is intravenous infusion?
    • apply tourniquet to limb
    • inject local analgesic into superficial vein of limb
    • numbs limb distal to tourniquet
  47. How long can the tourniquet be left on for intravenous infusion?
    no more than an hour and a half
  48. How do we remove a tourniquet after intravenous infusion? Why?
    • slowly over 5 minutes
    • to prevent large amounds of local analgesic from reaching the brain quickly
  49. What are some complications of local analgesic?
    • anaphylactic reaction
    • local damage
    • systemic toxicity
    • epidural complications
  50. What can cause local damage?
    • injecting into a nerve
    • local irritation
  51. If local analgesics reach high blood levels what can it affect?
    the brain and heart
  52. What are the clinical signs of local anaglesic toxicity in the brain?
    • sedation
    • muscle twitching
    • hyper-excitability
    • seizures
    • respiratory depression
  53. What is the treatment for toxicity in the brain?
    • diazepam
    • supportive
  54. What are some epidural complications?
    • trauma to spinal cord
    • infection
    • fibrosis
    • too cranial
  55. What can happen if an epidural is injected too cranially?
    • paralyze repiratory
    • bradycardia
    • hypotension
  56. What are the two types of ventilation?
    • assisted ventilation
    • controlled ventilation
  57. What is assisted ventilation?
    patient initiates each breath and anesthetist bags during the breath to increase tidal volume
  58. Assisted ventilation can be _____ or _____.
    continuous or intermittent (every 5 minutes or so)
  59. Why do animals "sigh"?
    • re-inflate partially collapsed alveoli
    • remove excess CO2
  60. What is controlled ventilation?
    • anesthestist controls both rate and depth of breathing
    • patient makes no spontaneous efforts to breathe
  61. What are the two different types of controlled ventilation?
    • manual
    • mechanical
  62. What is manual controlled ventilation?
    anesthetist bags patient every 5 seconds or so
  63. What is mechanical controlled ventilation?
    continuous ventilation by machine
  64. What does PPV stand for?
    positive pressure ventilation
  65. What is PPV?
    gases are pused into the patient's lungs by manual bagging or mechanical compression of bellows
  66. What is negative pressure ventilation?
    normal breathing or iron lung (chest expands when muscles of inspiration contracts and pulls gases into lungs)
  67. What is the purpose of PPV?
    anesthetized patient is often unable to breathe well enough on his own
  68. What is ventilation?
    moving gases into and out of the lungs
  69. Is inhalation active or passive?
  70. Is exhalation active or passive?
  71. What is inhalation initiated by?
    increased blood CO2 levels
  72. What is tidal volume?
    amount of gas that passes in and out of lungs per breath
  73. What is respiratory rate?
    breaths per minute
  74. In anesthetized patient's the brain is _____ to blood CO2 levels. It takes _____ CO2 level to initiate next breath.
    • less sensitive
    • higher
  75. Because anesthetized patients have lower respiratory rates what does this mean to the patient?
    • blood CO2 builds up
    • blood O2 decreases unless on 100% O2
    • atelectasis can occur
  76. How can the anesthestist compensate for the effects of a lower respiratory rate?
    • give 100% oxygen
    • bag the patient
  77. What is the procedure for manual ventilation?
    • close pop-off valve
    • press reservoir bag up to 20cm H2O
    • open pop-off valve
  78. What is the difference for non-precision vaporizer and precision vaporizers for bagging?
    • non-precision: turn off non-precision vaporizer for bagging
    • precision: no need to turn off
  79. What do we need to do with the precision vaporizor if we are totally controlling ventilation?
    turn it down or it will deliver a large volume of gas and the patient will go too deep
  80. When is controlled, continuous ventilation necessary?
    • thoracic surgery
    • respiratory disease
    • obese
    • debilitated
  81. What is the purpose of controlled ventillation?
    lowers patient's blood CO2 levels - less stimulus to breathe, spontaneous breathing stops
  82. What is the breaths per minute for controlled ventilation?
    8 - 12 breaths/minute
  83. How do we wean a patient off of controlled ventilation?
    • turn off vaporizer and N2O
    • continue 100% O2
    • gradually reduce bagging rate to about 5 per minute
  84. When is mechanical ventilation used?
    for controlled ventilation
  85. What does mechanical ventilation do?
    compression of bellows pushes gases into patient's lungs
  86. Where does the mechanical ventilation attach?
    to anesthesai machine at bag opening
  87. Types of mechanical ventilators deliver according to...
    • pressure
    • volume of gas
    • timing
  88. When is mechanical ventilation most commonly used?
    in thoracic surgery
  89. What are the risks of controlled ventilation?
    • pressure can get too high an can rupture alveoli
    • decreased cardiac output
    • excessive anesthetic vapor may be delivered if using VIC system
  90. When the alveoi ruptures what can it cause?
    • pneumothorax
    • mediastinal emphysema
  91. What does decreased cardiac output cause?
    high pressure in thorax which compresses vena cava
  92. What do muscle paralyzing agents do?
    affect voluntary skeletal muscle - stops impulses from going there
  93. When do we use muscle paralyzing agents in small animal anesthesia?
    • mechanical ventilation
    • orthopedics
    • Caesarian section
  94. How do we administer muscle paralyzing agents?
    • given after patient is anesthetized and ventilation is controlled
    • given IV slowly
  95. How long does muscle paralyzing agents last? Can we give repeated doses?
    • 10 - 30 minutes
    • yes
  96. What do muscle paralyzing agents do?
    interrupt transmission of impulse from nerve ending to muscle
  97. What are the two types of neuromuscular blocking agents?
    • depolarizing
    • non-depolarizing
  98. What do depolarizing agents do?
    causes surge of activity at neuromuscular junction followed by refractory period - muscles cannot accept impulses
  99. What do depolarizing agents do?
    block muscle receptors - muscles are unable to accept impulses
  100. Do reverser agents exist for depolarizing agents and depolarizing agents?
    • depolarizing agents: no reverser
    • non-depolarizing agents: reversers
  101. What do reversers do?
    • have parasympathetic side effects - bradycardia, salivation
    • pretreat patient with atropine or glyco
  102. What are some risks of neuromuscular blocking agents (muscle paralyzing agents)?
    • hypothermia
    • hard to assess depth of anesthesia
    • cannot assess pain
    • avoid in kidney and liver disease and glaucoma
  103. What drugs affect potency of neuromuscular blocking agents?
    • aminoglycosides
    • furosemides
    • organophosphates
    • corticosteroids
    • isoflurane
    • halothane
    • anticancer drugs
    • barbiturates
    • epinephrine
    • tetracycline