Relationship between Episodes of Sleep Apnea and Effects of UPPP in Patients with OSAS

Abstract

Uvulopalatopharyngoplasty (UPPP) a surgical treatment for obstructive sleep apnea syndrome (OSAS) fails to achieve satisfactory results in nearly half the patients. It would be desirable to predict the outcome preoperatively. We conducted all-night sleep tests of 23 patients (20 males and 3 females) before and after surgery to determine the indications for this procedure. All 23 patients had OSAS and were scheduled for UPPP. They were tested before and again 3 to 6 months after the operation. All 23 patients showed obstructive, central and mixed types of sleep apnea before UPPP. The effects of surgery were correlated with the distribution of the central and obstructive components during the total period of apnea (% of central component). To evaluate the test results, we calculated the Apnea Index, O₂ saturation C 90%, minimum O₂ saturation <90% and correlated the patients quantitative improvement following UPPP with the improvement in the % of central component. Patients with a % of central component below 15% had satisfactory improvement after UPPP. However, in patients whose % of central component exceeded 50% surgical results were not good. These results suggest that measurement of the % of central component with the all-night sleep test can help in the decision about the indications for UPPP. In conclusion, in all the patients with obstructive OSAS who were tested there were episodes of central apnea. The distribution of this central component was related to the outcome of UPPP. It is therefore important to investigate the episodes of apnea in detail before deciding on surgery.