OSA is far more common in adults than in children (
Figs. 51-1,
51-2,
51-3,
51-4,
51-5,
51-6,
51-7,
51-8,
51-9,
51-10 and
51-11). This disorder has an incidence in the adult population of approximately 1 in 4 men and 1 in 10 women.
6 Only a small percentage of these patients carry an official polysomnographic diagnosis of OSA. Most of the adults with OSA are undiagnosed. Therefore, the undiagnosed OSA patient will be the one most frequently encountered preoperatively. In the perioperative setting, these patients will present for all types of surgery, not solely airway surgery. In the elective situation, a high index of suspicion for OSA will serve the clinician well, as well as the judicious use of OSA-specific questionnaires. OSA is strongly associated with obesity, and the more obese the patient the more likely the incidence of OSA. Obesity results in fatty deposits in the tongue and upper airway,
which reduce lumen diameter and increase the likelihood of obstruction of the upper airway.
6 There are anatomical differences in the pharyngeal airway between OSA patients and controls. OSA patients have increased total fat volume surrounding the pharyngeal airway and greater airway collapsibility.
7 Additionally, nonobese OSA patients may have a shorter mandible, inferior hyoid, and retrognathic maxilla.
8 CT and MRI studies have shown OSA patients have a smaller airway lumen than controls. Neck circumference, male gender, and craniofacial anomalies also predispose the patient to OSA (
Table 51-3). Snoring is a very sensitive but nonspecific indicator of OSA.