Influence of Upper Airway Obstruction on Continuous Positive Airway Pressure

Min, Jin Young; Kim, Hyo Yeol; Chung, Seung Kyu; Dhong, Hun Jong; Chung, Young Jun; Bok, Kwon Hyo; Lee, Woo Young; Hong, Sang Duk

Abstract

BACKGROUND AND OBJECTIVES
: Nasal continuous positive airway pressure (CPAP) is a useful and efficient treatment modality, but the patient's compliance depends on several factors such as nasal CPAP level. The aim of this study was to evaluate the relationship between upper airway obstruction and nasal CPAP level in obstructive sleep apnea syndrome (OSAS).
SUBJECTS AND METHOD
: This retrospective study (from August 1995 through May 2005) included 50 patients suffering from OSAS with a mean apneahypopnea index of 43.78/hr, and those who underwent overnight polysomnography, laboratory nasal CPAP, and acoustic rhinometry(AR) for the measurement of minimal cross-sectional area (MCA) of the nasal cavity. We compared the nasal CPAP level with the degree of anatomic upper airway obstruction including tonsil and palate grade, MCA, subjective symptoms, or body mass index(BMI). A single linear regression analysis and one-way analysis of variance (ANOVA) were performed to compare variables.
RESULTS
: The mean nasal CPAP level was 6.32+/-2.17 cmH2O. We found a significant correlation between the nasal CPAP level and BMI (p<0.01) and the degree of palatine tonsil grade (p=0.01). Furthermore, AR measurements correlated with the nasal CPAP level (p=0.025) in patients with BMI<25. The other variables such as subjective symptoms, palate grade, and anatomic nasal obstruction in obese patients (BMI>25) revealed no correlation with the nasal CPAP level.
CONCLUSION
: Upper airway obstruction including nasal obstruction and tonsillar hypertrophy may increase the nasal CPAP level. Correction of nasal obstruction and tonsillectomy may reduce the nasal CPAP level in nonobese patients.