-Abstract-
Background and Objectives : Although it is widely accepted that nasal obstruction leads to snoring and
sleep apnea, the relationship between these variable is not clear. Moreover, while nasal blockage in human
is known to produce sleep disordered breathing, it is controversial whether nasal obstruction itself
produces obstructive apnea and whether it causes changes in the sleep stages. The purpose of this study
is to measure changes in sleep physiology by nasal blockage alone and to evaluate whether the nasal
blockage itself can produce the sleep apnea syndrome or not. Material and Method : Normal thirty
subjects, 15 males and 15 females, who had sleep apnea episodes <2 by polysomnography during sleep,
were evaluated using Alice Ⅲ polysomnography after both nostrils opened, unilateral nostril blockage, and
bilateral nostril blockage, and bilateral nostril blockage. The parameters of measurement were hypopnea
and apnea episodes and apnea type, apnea index (AI), respiratory disturbance index (RDI),
SaO2, and sleep stages. A statistical analysis was performed suing a wilcoxon signed rank
test. Result : Bilateral nasal blockage induces significantly increased apnea and hypopnea episodes, AI, and
RDI but induces significantly decreased mean and lowest O2 saturation. Also, bilateral nasal
blockage significantly prolonged S2-NREM sleep and decreased REM sleep (p<0.05).
However, these changes did not correspond with the criteria of the sleep apnea syndrome. Conclusion :
Unilateral nasal obstruction does not cause any significant changes in the measured parameters compared
to the normal nose of unblocked state. Bilateral nasal obstruction does not induce the obstructive sleep
apnea syndrome by itself. However, it causes changes in the sleep stages and increases sleep apnea
episodes significantly.
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