Standard Tracheal Extubation
Postoperative tracheal extubation is an elective procedure and should be carefully planned and controlled (19). Generally accepted tracheal extubation criteria are recovery of consciousness, spontaneous breathing, and neuromuscular blockade, cardiovascular stability, normothermia, and laryngeal patency (20). When planning routine tracheal extubation, a risk stratification should be performed in advance to identify patients with intermediate-risk extubations (11); special attention should be directed to patients with obstructive sleap apnea (OSA), morbid obesity (MO), and increased risk of pulmonary aspiration.
Preparations for Tracheal Extubation
The optimum patient positioning for tracheal extubation is controversial; some favor the left lateral, head-down position, particularly in patients with increased risk of pulmonary aspiration (25). Nevertheless, patients with MO should be extubated in the ramped, head-elevated position as recommended for induction of general anesthesia (GA) and tracheal intubation (17); this position may improve oxygenation and spontaneous breathing and may facilitate airway interventions and tracheal reintubation when necessary.
Preoxygenation before tracheal extubation is common clinical practice; this measure may provide a greater margin of safety by delaying severe arterial desaturation when airway problems arise. Unfortunably, high inspired oxygen concentrations promote atelectasis formation (6) which may contribute to postoperative pulmonary complications. Therefore, we recommend a more moderate use of oxygen in patients with low-risk tracheal extubations; high inspired oxygen concentrations should be limited to patients at risk for tracheal extubation failure.
Tracheal and oropharyngeal suctioning of secretions should be performed while the patient is still deeply anesthetized because any kind of stimulation and in particular irritation of the vocal cords at a light plane of GA may provoke laryngospasm. Tracheal extubation during application of positive airway pressure is an additional means of removing secretions around and below the laryngeal aperture.
Timing of Tracheal Extubation
Tracheal extubation may be performed before or after recovery of consciousness (20), termed as deep and awake extubation. The relative merits of deep extubation are avoidance of adverse pressure responses to extubation; however, the incidence of respiratory complications in adult patients after deep extubation may be higher than observed under awake extubation (4). The alternative method is substituting a laryngeal mask airway (LMA) for the tracheal tube while the patient is still anesthetized, with subsequent removal of the LMA when the patient resumes spontaneous breathing and consciousness.
Deep extubation should be performed only by experienced operators or under expert supervision. The principal disadvantages of deep extubation are the increased risk of upper airway obstruction and inadequate airway protection rendering the patient prone to pulmonary aspiration. Therefore, awake extubation should be performed particularly in patients with OSA, MO, and increased risk of pulmonary aspiration.
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