Objective: To predict and optimal level of continuous positive airway pressure (CPAP) in the menagement of obstructive sleep apnea syndrome (OSAS) by relating certain parameters of respiratory disturbance and sleep hypoxemia.
Methods: 18 patients with OSAS (all male, aged 48 +/- 11 yrs) were enrolled in the study. Their actual levels of CPAP (Pm) were determined by a RHK-5500 mode polysomnographic system plus BiPAP (ST/D) system. The actuual Pm was related to the respiratory disturbance index (RDI) or total time of SaO2 < or = 90% (T S90). The correlation regression equations were calculated. 6 patients with OSAS (Group A) were treated with the predicted nasal CPAP (predicted Pm) which was derived from the regression equation, 8-10 hours per night, for 5-7 nights. 13 patients (Group B) receiving nasal CPAP treatment using the actually measured Pm served as control.
Results: There was a close positive linear correlation between RDI or T S90 and actual Pm. Symptoms and polysomnographic parameters improved significantly after one course of CPAP treatment in Group A. The efficacy showed no signifcant different as compared with that in Group B.
Conclusions: It was suggested that RDI or T S90 are of value and simple in predicting the pressuure level of CPAP in the management of OSAS with nasal CPAP.