OBJECTIVETo explore the relationship of continuous positive airway pressure and pulmonary function in patients with obstructive sleep apnea hypopnea syndrome (OSAHS), and formulate the prediction equation for the effective therapeutic pressure.

METHODSIn a retrospective cross-sectional study of 48 patients with established OSAHS, all the patients were carefully examined for their medical history, and overnight sleep monitoring was carried out to measure the sleep apnea-hypopnea index, mean oxygen saturation, minimum oxygen saturation, and oxygen drop index. The data of manual pressure titration (effective pressure) and pulmonary function tests (tidal volume, one second forced expiratory volume, central airway resistance, and peripheral airway resistance were collected for multiple linear regression analysis.

RESULTSThe effective therapeutic pressure was not correlated with the indices of the pulmonary functions in the patients, but showed correlations with the neck circumference, abdominal circumference, apnea-hypopnea index, mean oxygen saturation, least oxygen saturation, and oxygen desaturation index. Multiple linear regression (α=0.05 test level) identified only oxygen desaturation index (P=0.012) and mean oxygen saturation (P=0.036) as the dependent variables of the effective therapeutic pressure. Linear regression analysis showed that the effective therapeutic pressure had a linear relationship with the oxygen drop index and mean oxygen saturation, and was inversely correlated with the mean oxygen saturation.

CONCLUSIONSIn patients with OSAHS, the pulmonary function indices are not correlated with the effective therapeutic pressure. In the absence of manual pressure titration, the effective therapeutic pressure can be predicted using the prediction equation: effective therapy pressure = 24.262+0.044×oxygen desaturation index -0.19×average oxygen saturation.