Comparison of Correlation of Subjective Symptoms Between Total Respiratory Disturbance Index and Supine Respiratory Disturbance Index

ABSTRACT

BACKGROUND AND OBJECTIVES: The aggravating effect of the supine body position on breathing abnormalities during sleep appears to be due to the effect of gravity on the upper airway. All patients have a higher supine RDI (respiratory disturbance index) than total RDI. The body position during sleep may be the cause of night-to-night variability in the results of the polysomnography (PSG). The aim of this study is to compare the correlation of subjective symptoms with supine RDI and total RDI. MATERIALS AND METHOD: One hundred and twenty nine patients who visited for snoring and/or apnea, excessive daytime sleepiness were included in the study. All patients underwent full night PSG and were administered 10 cm visual analogue scale (VAS) for 14 symtoms and Epworth sleepiness scale (ESS). Supine RDI, lateral RDI and total RDI were measured in PSG. Patients were divided to positional patients (PP) and non-positional patients (NPP). RESULTS: Fifty of 97 obstructive sleep apnea patients (51.5%) were divided into PP group and 47 patients (48.5%) were divided into NPP group. Several symptoms had correlation with supine RDI and total RDI. In correlated symptoms, total RDI had higher correlation coefficient than supine RDI in both PP group and NPP group. CONCLUSIONS: Our results suggest that total RDI may reflect patient's subjective symptoms.