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Anesthetic Emergence
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Anesthetic Emergence

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Anesthetic Emergence Anesthetic Emergence Presentation Transcript

  • ANESTHETIC EMERGENCE
    Alan Julius Sim, MD, Fellow
    Divison of Liver Transplantation
    Mount Sinai HELPS Center
    Department of Anesthesiology
    Mount Sinai School of Medicine
    New York, NY
  • Famous Quotes
    “Never say their name more than twice, otherwise you’ll look like you don’t know what you’re doing”
    Ian Sampson, MD
    “Dude, just cause you put the tube in dosen’t mean you gotta take it out”
    KhinMarlar, MD
    “Every textbook tells you how to put someone to sleep, no book will ever tell you how to wake someone up”
    Samuel DeMaria Jr., MD
    “As long as their breathing on their own, not in pain, and have a pulse, I don’t care what you gave”
    Corey Scher, MD
  • Objectives
    Plan and implement an appropriate emergence technique
    Assess depth of neuromuscular blockade
    Reverse neuromuscular blockade
    Remove or discontinue maintenance anesthetics (inhaled or intravenous)
    Verify reversal of neuromuscular blockade
    Ensure adequate post-operative analgesia
    Extubate patient safely
    Potential problems
  • Emergence Philosophy
    Most anesthesiologists, surgeons, and nurses will place a premium on a “smooth” emergence, free of coughing, straining, or arterial hypertension
    It should be acknowledged that there is a paucity of clinical data to give any perspective to the actual magnitude of risks associated with an emergence that is not “smooth”
  • Planning Emergence
    When do you start to prepare for emergence?
  • Planning Emergence
    When do you start to prepare for emergence?
    Prior to Induction of Anesthesia
    Shorter acting agents for shorter cases
    Avoid excessive premedications
    Prepare to switch techniques or agents at the end of a longer case
    Time your medications and doses
  • Assess Depth of NMB
    How can you assess depth of neuromuscular blockade?
  • Assess Depth of NMB
    How can you assess depth of neuromuscular blockade?
    Objectively
    Train of Four – Adductor Pollicis or OrbicularisOculi
    95% – 1 twitch
    90-95% - 2 twitches
    80-85% - 3 twitches
    75-80% - 4 twitches
    >100% ???? - 0 twitches
    Subjectively
    Timing and amount of last dose
    Spontaneous respiratory effort
  • Assess Depth of NMB
    When can I reverse?
  • Assess Depth of NMB
    When can I reverse?
    Objectively
    Post-tetanic stimulation and return of 1 twitch = 10 mins
    At least 1 twitch represents 95% blockade and no free drug
    Therefore, reliably reversible
    Subjectively
    Spontaneous respiratory effort
    Less than 100% blockade
    Therefore, reliably reversible
  • Reverse NMB
    How do I reverse NMB?
    What agents do we use?
    How do they work?
  • Reverse NMB
    How do I reverse NMB?
    Anticholinesterase Inhibitors
    Edrophonium 1-1.5mg/kg
    Neostigmine 0.04-0.08mg/kg
    Pyridostigmine 0.1-0.25mg/kg
    These agents increase Ach EVERYWHERE, ideally want to isolate only nicotinic receptors and avoid muscarinic action and cholinergic crisis
    Therefore, must administer concurrently anticholinergics
    Atropine 0.4-1mg
    Glycopyrolate 0.2-1mg
  • Reverse NMB
    How fast does reversal work?
  • Reverse NMB
    How fast does reversal work?
    Dependent on five factors
    Depth of block
    Greater blockade = more to reverse
    Type of anticholinesterase
    Edrophonium > Neostigmine > Pyridostigmine
    Dose of anticholinesterase
    Maximum dose
    Too much ACh can cause depolarizing blockade
    Spontaneous reversal and metabolism of NMB agent
    Intermediate vs. Long, patient factors
    Concentration of anesthetic gas
    Increased depth of inhaled augments blockade
  • Reverse NMB
    Any side effects of over-reversal?
  • Reverse NMB
    Any side effects of over-reversal?
    Cholinergic Crisis
    Wet
    Bronchospasm
    Paralysis
    Bradycardia
    Anti-Cholinergic Crisis
    Dry
    Hyperthermia
    Urinary Retention
    Tachycardia
    Delayed emergence
  • Reverse NMB
    Atropine or Glycopyrrolate?
  • Reverse NMB
    Atropine or Glycopyrrolate?
    Atropine
    Better timing with edrophonium
    Quicker onset of action
    7 to 10 µg/kg of atropine should be given with 0.5 to 1.0 mg/kg of edrophonium
    Crosses Blood-Brain barrier  Sedation/Hallucinations
    Glycopyrrolate
    Better timing with neostigmine
    Less profound tachycardia
    Better anti-sialigogue
    7 to 15 µg/kg of glycopyrrolate should be given with 40 to 70 µg/kg of neostigmine
    Quaternary structure
  • Anesthesia “Off”
    How do I go about doing this?
  • Anesthesia “Off”
    How do I go about doing this?
    Inhaled
    Dependent upon ventilation, FGF, and concentration gradient
    Low Flow and Hypoventilation = Slow
    High Flows and Hyperventilation = Fast
    Blood:Gas Solubility and Lipid Solubility
    Why does Desflurane take longer than N2O?
    Intravenous
    Dependent on beta half-life and length of infusion
    No end-tidal propofol
    Wake up will also depend on patient and level of stimulation!
    Most importantly COMMUNICATE!!
  • Verify NMB Reversal
    How do I know I’m fully reversed?
    Is spontaneous breathing OK with adequate tidal volumes?
  • Verify NMB Reversal
    How do I know I’m fully reversed?
    Objective
    TOF, seeing 4 twitches are subjective and indicate only 75% blockade
    Sustained tetanus 50-100Hz >5s without fade indicates only 50% blockade
    TOF ratio of >0.7-0.9 is the gold standard
    Subjective
    5 sec head lift
    Tongue protrusion
    Forced hand grip
    Spontaneous breathing with adequate TV is still unreliable as diaphragm much more resistant to NMB than airway muscles (i.e. tongue)
  • Post-Operative Analgesia
    How can I prevent my patient from waking up in pain?
  • Post-Operative Analgesia
    How can I prevent my patient from waking up in pain?
    Timing of narcotics (onset and duration)
    Use longer acting narcotics early
    Titrate shorter acting narcotics to respiratory rate
    Use doses appropriate for “awake” patients
    Use adjuncts
    Acetaminophen
    Gabapentin
    Ketorolac
    Regional
    Block
    Local infiltration
  • Post-Operative Nausea
    How can I prevent my patient from puking in my face?
  • Post-Operative Nausea
    How can I prevent my patient from puking in my face?
    Avoid nauseating anesthetics
    Opioids
    Nitrous Oxide
    Anticholinesterase Inhibitors
    Use antiemetics appropriately
    Dexamethasone 4mg pre-incision
    Ondansetron 4mg pre-induction or 30 mins prior to emergence
    Droperidol 0.625-1.25mg
    Propofol 20-30mg close to emergence
  • Extubation
    When do I pull the tube? Deep or Awake?
  • Extubation
    When do I pull the tube? Deep or Awake?
    Deep Extubation
    Patient Selection
    Recovery of NMB must be confirmed
    > 1 MAC
    RR < 15
    Clear secretions
    Always prepare for laryngospasm and reintubation
    Need PACU cooperation
    “Smooth”
    Often Risk > Benefit
  • Extubation
    When do I pull the tube? Deep or Awake?
    Awake Extubation
    Mental Status
    Follows commands
    Airway
    Can protect airway
    Appropriate cough or gag “Bucking”
    No edema
    Difficult intubation?
    Respiratory Mechanics
    Strong
    SpO2 > 93% on FiO2 < 0.5
    Hemodynamics
    Stable
    Unlikely coming back to OR
  • Style Points: Art or Science?
    When is the patient ready to wake up?
  • Style Points: Art or Science?
    When is the patient ready to wake up?
    Make sure surgery is done first
    Look for hemodynamic changes
    Increase HR
    Increase BP
    Return of reflexes
    Swallowing
    Lid reflex
    Glabellar Tap
    Can call first name if reflexes have returned
  • Style Points: Art or Science?
    How do I extubate awake but without bucking?
  • Style Points: Art or Science?
    How do I extubate awake but without bucking?
    Bucking is a reflexive response to a noxious stimulus
    Narcotics attenuate this response
    LTA or lidocaine will “numb” the cords
    Hyperventilation or hypocarbia will decrease drive to breathe against vent
    Turn vent off upon recognition of patient wakefulness
    Awake patients on narcotics can and will breathe
    You just may have to tell them to
  • Style Points: Art or Science?
    There are three commonly practiced emergence “techniques” at Mount Sinai, each with unique advantages and disadvantages
    Traditional
    The 15/15
    The Crash Wake-Up
  • Style Points: Art or Science?
    Traditional Wake-Up Method
    Reverse NMB
    “Lighten” anesthetic
    Increase EtCO2
    Return to spontaneous breathing
    Titrate narcotics to RR
    Extubate when patient is awake and following commands
    Advantages
    Smooth, adequate analgesia, comforting
    Disadvantages
    Requires breathing patient
    Slow, hypoventilation decreases elimination of anesthetic
    Increased side effects of narcotics
  • Style Points: Art or Science?
    The 15/15
    Reverse NMB
    Titrate down inhaled anesthetic
    Dose narcotics appropriately
    15L FGF 15 RR
    Hyperventilate inhaled gas off
    Extubate when patient is awake and following commands
    Advantages
    Fast emergence, smooth when timed correctly
    Disadvantages
    May not adequately ensure post-operative analgesia
    Overdose or underdose narcotics to RR
  • Style Points: Art or Science?
    The Crash Wake Up
    Full Reverse NMB
    15L FGF 15 RR
    Hyperventilate inhaled gas off
    Push Naloxone
    Pinch Nipples
    Jaw-Thrust
    Extubate when patient is awake and following commands
    Advantages
    Fast emergence when unprepared
    Disadvantages
    Never smooth
  • Potential Problems
    “Patient is too tight, need a little bit longer”
    “The medical student is going to close”
  • Potential Problems
    “Patient is too tight, need a little bit longer”
    Push something
    ED95 of muscle relaxants is usually 1/3 intubating dose
    Propofol
    Lidocaine 1-1.5mg/kg
    Push nothing
    Increase inhaled concentration
    N2O
    Communicate
  • Potential Problems
    “He’s waking up all crazy”
  • Potential Problems
    “He’s waking up all crazy”
    Emergence Delrium
    Can happen if wake up is too fast or inadequate pain control
    Rule out: Hypercarbia, Hypoxia, Hypotension
    Stage II anesthesia
    What to do
    Don’t pull out ETT if haven’t already
    Stop and hit rewind Propofol
    Fentanyl
    Droperidol
    Avoid benzos if possible
  • Potential Problems
    “I pulled the tube and uhhh…he stopped breathing”
  • Potential Problems
    “I pulled the tube and uhhh…he stopped breathing”
    Most anesthetic mishaps happen from extubation to PACU
    Rule out laryngospasm vs. apnea
    If apnea, attempt to ventilate off residual gas and stimulate
    Consider naloxone, residual NMB
    If laryngospasm, sustained PPV and prepare succynlcholine
    Both cases prepare to re-intubate
    Succynlcholine in successive doses?
    Do not leave OR until you are assured patient is OK
    Be prepared for long trips
  • Potential Problems
    “Why won’t he wake up?”
  • Potential Problems
    “Why won’t he wake up?”
    Delayed emergence
    Rule out: Hypercarbia, Hypoxia, Hypotension
    Intoxication
    Inadequate Reversal or Prolonged Paralysis
    Phase II block?
    Psudeocholinesterase deficiency
    Metabolic
    Hyper/Hyponatremia
    Hyper/Hypoglycemia
    Neurologic
    Stroke
    If residual paralysis, obligated to keep patient asleep
  • Summary
    Emergence is an art, there are many ways to do it
    There is a lot of science to it also
    Certain components must be performed
    Reversal is not benign
    But necessary if you paralyze
    Communication is key
    Involve yourself with the case at hand, and you will time everything perfectly
    Never compromise patient safety
    Anoxic brain injury infinitely much worse than “bucking”
  • Thank You
    “That was the best wake up I’ve ever seen, by the way, we’re number 12 for PACU”