S2E7 - Emergence

Airwayve

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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