S2E7 - Emergence

Airwayve

Nov 16 2020 • 24 mins

What is emergence? The time from discontinuation of an anesthetic to when the patient can make a non-reflex response to verbal command

Maneuvers to improve the elimination of inhaled anesthetics:

  • Increase FiO2
  • Increase gas flow rate
  • Increase PEEP to prevent atelectasis

Factors that affect emergence:

  • Patient factors (e.g. obesity, advanced age, hepatic or renal insufficiency)
  • Drug factors (e.g. dosage, time of administration, metabolism, excretion)
  • Surgical factors (e.g. length/type of surgery)

Reversal of neuromuscular blockade:

  • Acetylcholinesterase inhibitor (e.g. neostigmine): increases amount of acetylcholine at the neuromuscular junction to reverse paralysis; also increases acetylcholine in the parasympathetic nervous system
  • Muscarinic receptor antagonist (e.g. glycopyrrolate): inhibits the parasympathetic effects of neostigmine

Postoperative considerations:

  • Antiemetics: ondansetron, dexamethasone, aprepitant
  • Postoperative pain medications: long-acting narcotics, NSAIDs (e.g. ketorolac), acetaminophen

Extubation criteria:

  • Hemodynamically stable
  • Respiratory rate between 8-35
  • Adequate oxygenation (PaO2 at least 60 mmHg with FiO2 <50%, or PaCO2 < 50 mmHg)
  • Tidal volume > 5 ml/kg
  • Negative inspiratory force of at least 25 mmHg, and vital capacity of 15 mL/kg
  • Can also look for purposeful movements such as opening eyes or following commands

Respiratory complications are about 3 times more likely to occur during extubation than intubation

Steps to extubation:

  • Deflate the cuff
  • Gently remove tube
  • Have suction ready, clear secretions prior to extubation and afterwards
  • Have oxygenation equipment ready
  • Remove monitors from the patient when appropriate (typically remove the oxygen saturation probe last)

Extubation complications:

  • Airway obstruction
  • Early postoperative hypoxemia
  • Heightened cardiovascular response
  • Aspiration
  • Emergence delirium

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