Objective  To explore the effect of continuous positive airway pressure (CPAP) on the efficacy and sleep structure of patients with severe obstructive sleep apnea hypopnea syndrome (OSAHS) undergoing uvulopalatopharyngoplasty (UPPP).

  Methods  Totally 40 patients with severe OSAHS were randomly divided into control group and continuous positive airway pressure (CPAP) group. Patients in the control group were treated with modified UPPP, and CPAP group was treated with CPAP on the basis of the control group. Polysomnography (PSG) monitoring results were compared between the two groups before and 6 months after treatment, including apnea hypopnea index (AHI) per hour, minimum blood oxygen saturation (LSaO₂) and maximum apnea time (LAT). The sleep structure and sleep quality before and after treatment were compared between the two groups.

  Results  After treatment, AHI and LAT in both groups significantly decreased (P < 0.05), LSaO₂ significantly increased (P < 0.05), and the changes in CPAP group were significantly greater (P < 0.05). After treatment, the proportion of phase 1 to 2 and micro-arousal index in both groups decreased significantly (P < 0.05), the proportion of phase 3 to 4 and REM increased significantly (P < 0.05), and the changes in CPAP group were significantly greater (P < 0.05). After treatment, the PSQI scores of the control group and CPAP group were significantly lower than those before treatment (P < 0.05), and the changes of CPAP group were significantly greater (P < 0.05).

  Conclusion  CPAP can effectively improve the therapeutic effect of patients with severe OSAHS by modified UPPP and improve the sleep structure and sleep quality.