Normal standard curve for acoustic pharyngometry.

Pharyngeal size, compliance, and the dynamic behavior of the upper airway are important factors in the production of obstructive sleep apnea. Assessment of the upper airway for possible site(s) of obstruction is one of the keys to a successful management of the condition. Acoustic pharyngometry has the potential for localizing such sites, however, standardizing the operating technique and producing a standard normal curve is a prerequisite before exploring the potential of this equipment. A total number of 350 normal volunteers (271 males and 79 females) were examined by acoustic pharyngometry and a coefficient of variance of 5% to 7% was obtained from each of them. Mean and standard deviation of pharyngeal area at each point of X-axis (distance) was obtained and analyzed statistically to produce a general standard curve. Using special techniques during examination, the oropharyngeal junction and glottis were located, and thus a mapped acoustic pharyngogram was produced. Mean pharyngeal area was 3.194 cm(2) in males (SD 0.311) and 2.814 cm(2) in females (SD 0.331). Mean glottic area was 1.06 cm(2) in males (SD 0.119) and 0.936 cm(2) in females (SD 0.108). A minimal pharyngeal area is probably needed as a "golden standard" to evaluate patients with obstructive sleep apnea.