Question: The obturator or catheter in a tracheostomy cannula serves to: 
 Options:  <1> Introduce the external cannula into the tracheal stoma in a non traumatic way. <2> Aspirate secretions if a vacuum source is directly connected. <3> Help maintain the permeability of the artificial airway. <4> Fix the cannula avoiding its accidental displacement. <5> Allow the patient to speak by allowing the air to pass through the vocal cords.
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