Objective: Oxygen desaturation is common among patients with sleep apnea. This study was designed to evaluate the methods used to express the severity of oxygen desaturation in patients with obstructive sleep apnea hypopnea syndrome.
Methods: The oxygen saturation data of 215 patients [suspected of having obstructive sleep apnea (OSA)] studied at the Sleep Centre of Peking Union Medical College Hospital were evaluated. Apnea-hypopnea index (AHI) and the following conventional indices of oxygen desaturation were compared: average oxygen saturation (AO(2)), lowest oxygen saturation (LO(2)), oxygen desaturation index (ODI), average desaturation and the percent of the total time with oxygen saturation level lower than 90% (T < 90%).
Results: There was a significant correlation between the oxygen saturation values measured by any method (AO(2), LO(2), ODI, average desaturation, T < 90%) and the severity of sleep AHI (r = -0.610, 0.983, -0.789, 0.782, 0.821, respectively, P = 0.001).
Conclusions: The best method of expressing the severity of oxygen desaturation in patients with obstructive sleep apnea hypopnea syndrome needs the combination of several conventional indices of oxygen desaturation (lowest oxygen saturation, oxygen desaturation index, and the percent of the total time with oxygen saturation level lower than 90%).