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A second group of respiratory complications that may arise in the course of outpatient anesthesia includes reactive airway conditions such as laryngospasm, bronchospasm, and acute asthma. One analysis of complications in ambulatory anesthesia identified laryngospasm, stridor, and obstruction as the most frequently observed adverse events, accounting for 40% of complications [15]. Acute asthma attacks are more frequent preoperatively and may be associated with patient anxiety. Laryngospasm and bronchospasm typically result from the combination of airway irritation and anesthetic sedation.

Acute asthma and bronchospasm are manifested clinically by audible wheezing (more prominent during expiration), tachypnea, shortness of breath, and are usually accompanied by decreasing oxygen saturation. They represent a hyperreactive process of the large airways that results in bronchoconstriction and obstruction to airflow. A number of factors may precipitate an asthma attack or bronchospasm, but in an oral surgical setting anything that causes airway irritation may be the predominant etiological factor. Some examples include the production of aerosols during a procedure or decreased clearance of secretions that can irritate the airway and stimulate coughing. Laryngospasm, in contrast, is an acute upper airway obstruction that presents with stridor (incomplete laryngospasm) or failure of ventilation (complete laryngospasm with total closure of the glottis). Obstruction of the upper airway due to foreign body aspiration may also present with acute stridor and should be ruled out clinically. Laryngospasm results in reflexive closure of the glottis upon irritation and is a protective airway reflex. It does not occur in awake patients or in patients during general anesthesia, but can occur in a mild or moderate stage of sedation [16].

Acute asthma attacks may be managed with inhaled beta‐2‐agonist bronchodilator medications such as albuterol. These drugs are typically administered via a metered‐dose inhaler either with or without an additional spacer device. Patients who are awake and alert may be allowed to self‐administer the inhaled medication, while patients who are sedated may need assistance. In sedated patients, the use of a spacer may be particularly useful to assist delivery of the drug to the lungs and to prevent excess drug deposition in the oropharynx where it is has no therapeutic effect.

Inhaled bronchodilators are also the first‐choice treatment for bronchospasm and are administered similarly. In intubated patients, these inhaled medications may be administered via ET or LMA, though the dosage must be greatly increased (up to 10–20 puffs) to account for the large amount of drug that coats the airway tube and does not reach the lungs. Both acute asthma and bronchospasm benefit from supplemental oxygen. In severe cases that do not respond to inhaled beta‐agonists, IV or subcutaneous epinephrine may be considered as a rescue therapy. The adverse effects of epinephrine – particularly tachycardia and increased blood pressure – limit its use for reactive airway disease. It should be used with extreme caution, if at all, in patients with underlying cardiac disease.

The treatment of laryngospasm differs from that of asthma or bronchospasm. Because it occurs in patients who are at “lighter” levels of anesthesia, deepening the level of anesthesia will help to abolish the protective airway reflex and relax the vocal cords to allow the passage of air. Positive pressure ventilation, especially when instituted early in the course of the laryngospasm, is frequently successful at “breaking” the spasm. If it appears that secretions or bleeding in the oropharynx may be contributing factors, a brief period of suctioning with a tonsillar (Yankauer) suction may be helpful. Care should be taken that this does not delay positive pressure ventilation, however, and that the suction itself does not serve to further provoke the laryngospasm reflex. If neither deepening the anesthesia nor positive pressure ventilation proves successful, the treatment of choice for laryngospasm is the administration of the neuromuscular blocking agent succinylcholine. Succinylcholine for the treatment of laryngospasm is typically given at a dose of 20–40 mg initially, with an additional 20–30 mg given a minute or two later if the first dose proves insufficient [18]. This dose is less than the “standard intubating dose” of succinylcholine, but whenever a paralytic agent is given, it is safest to assume that complete paralysis may occur and the practitioner should be prepared to assist the patient's ventilation until the drug has adequately worn off and the patient is ventilating well without assistance.