[Upper airway finding on CT scan with and without nasal CPAP in obstructive sleep apnea patients]

The area of upper airway (from the nasopharynx to the hypopharynx) was measured by means of computed tomography (CT) scan in 15 confirmed cases of obstructive sleep apnea (OSA) and in 4 normal controls while they were awake. The minimum cross-sectional area (MA) of the upper airway was 14.7 +/- 20.0 mm2 in OSA patients and 80.0 +/- 33.1 mm2 in normal controls and the difference was statistically significant (p less than 0.01). In OSA patients, MA did not correlate with age, body weight, apnea index, desaturation index, mean nadir-SO2 and lowest SO2. MA was also measured with OSA patients while nasal continuous positive airway pressure (NCPAP) of 10 cmH2O was applied and it was found that MA was significantly widened when NCPAP therapy was performed. We conclude that upper airway narrowing is consistent finding in OSA patients but the degree of narrowing does not correlate with parameters of apnea and gas exchange during sleep, and NCPAP is effective to widen the area of upper airway in OSA patients.