The Effect of Body Posture on the Severity of Obstructive Sleep Apnea Syndrome: Comparison of RDI According to BMI and the Anatomic Characteristics of Upper Airway / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: It is reported that positional therapy, i.e. the avoidance of the supine posture during sleep, is a simple behavioral therapy effective for many OSA patients and that the efficacy of this positional therapy influences RDI and BMI. However, there are no available data on Asians related to positional therapy and little has been studied about the anatomic characteristics of the upper airway. So, we attempted to observe in Korean OSA patients to see how RDI is influenced according to sleep positions and estimate the efficacy of positional therapy according to the degree of tonsillar hypertrophy and the degree of obstruction of oropharynx and hypopharynx. SUBJECTS AND METHOD: We evaluated 112 patients whose RDI were over 5 and whose sleep time of supine position/non-supine position went over 30 minutes as a result of overnight polysomnography taken from December 2003 to July 2004 at the Asan Medical Center. RESULTS: RDI was reduced to the average of 68.7% on non-supine position. The prevalence of positional patients in Korean OSA patients was 76.8%. Positional RDI reduction rate of the obese class II (BMI>30), grade IV oropharyngeal obstruction group on Muller maneuver was significantly lower compared to the other groups. CONCLUSION: The positional therapy was more effective in the Korean OSA patients than in the western OSA patients. However, in the obese class II and the grade IV oropharyngeal obstruction, the efficacy of the positional therapy was lower compared to the other groups.