Analysis of age effect to determine optimal nasal pressure in Korean patients with obstructive sleep apnea

Abstract

Introduction Determining of the optimal CPAP pressure is the key procedure of applying adequate CPAP for patients with Obstructive Sleep Apnea (OSA). There are some studies for predictors of optimal CPAP pressure, most of them emphasized the apnea hypopnea index, importance of anthropometric factors, especially body mass index, neck circumference. As The purpose of this study is to analysis of aging factors affecting CPAP pressure as well as polysomnographic data in Korean patients with OSA Materials and methods We retrospectively reviewed the records of 169 Korean patients with OSA who had undergone CPAP titration at the Sleep Clinic of Kyung Hee university hospital at Gangdong. The patients were examined by otolaryngologist for grading the anatomy of nasopharyngeal, oropharyngeal, retropharyngeal area before diagnostic polysomnography. Anthropometric data was consisted of Friedman palate position, modified Friedman palate position, Tonsil hypertrophy grade, nasopharyngeal endoscopy, retropharyngeal grade, uvular size and body mass index (BMI). We divided them subgroups according to age ; below 40 (group 1, n = 38, male 37, female 1), 41 ∼ 60 (group 2, n = 98, male 91, female 7), above 60 years old (group 3, n = 32, male 29, female 3). Results The mean optimal CPAP pressure in 169 patients was 8.40 ± 2.73 cmH2O and the apnea hypopnea index (AHI), respiratory distress index (RDI), arousal index (AI) and BMI were correlated with optimal CPAP level. There were no difference optimal CPAP pressure and modified Friedman palate position, tonsil hypertrophy grade, nasopharyngeal endoscopy, uvular size between groups. But, the retropharyngeal grade was correlated with optimal CPAP pressure in young age group. Patient with low optimal pressure group had tendency of longer uvula and Patient with high optimal pressure group had more narrow retropharyngeal area than in patient with low optimal pressure. Conclusion Our study shows that anatomic problem of retropharyngeal area influence to high optimal pressure only in young OSA patient. Previous studies for affecting factor of optimal CPAP pressure focused anthropometric factors. Our study suggests that functional problem as well as retropharyngeal anatomy may affect to determine optimal CPAP pressure in old OSA patient.