[Vocal cord paralysis associated with tracheal intubation: incidence, risk analysis, and classification of severity]

Vocal cord paralysis after tracheal intubation is rare. It causes severe hoarseness and aspiration, and delays recovery and discharge. Arytenoid cartilage dislocation and recurrent nerve paralysis are main causes of vocal cord paralysis. Physical stimulation of the tracheal tube as well as patient and surgical characteristics also contribute. Vocal cord paralysis occurs in 1 (0.07%) of 1,500 general surgery patients and on the left side in 70% of cases. It is associated with surgery/anesthesia time (two-fold, 3-6 hours; 15-fold, over 6 hours), age (three-fold, over 50 years), and diabetes mellitus or hypertension (two-fold). Symptoms resolve in 2-3 months. In adult cardiovascular surgery, vocal cord paralysis occurs in 1 (0.7-2%) of 50-100 cardiac surgery patients and 1 (8.6-32%) of 3-10 thoracic aortic surgery patients. In pediatric cardiac surgery, vocal cord paralysis occurs in 1 (0.1-0.5%) of 200-1,000 patients. We classified the severity of vocal cord paralysis as I, severe hoarseness; II, aspiration or dysphagia; and III, bilateral vocal cord paralysis, aspiration pneumonia, or the need for tracheal re-intubation or tracheotomy. We discuss the importance of informed consent for the patient and family.