Total and unilateral nasal resistance in 48 patients with sleep apnea syndrome (SAS) and 35 normal subjects were compared upright and supinely to determine the importance of nasal resistnce in supine SAS patients. Active anterior rhinomanometry was conducted with a Nippon Kohden MPR-3100 rhinomanometer to measure unilateral (inspiratory and expiratory) and total (inspiratory and expiratory) nasal resistance.
Total (both expiratory (Δ100Pa andΔ150Pa) and inspiratory (Δ100Pa) ) nasal resistance in normal subjects increase more significantly in supine than upright subjects. Total inspiratory (Δ100Pa) nasal resistance in SAS patients increases more significantly in supine than upright patients. No correlation was seen between BMI and increasing nasal resistance in changing from supine to upright in normal subjects and SAS patients.
In conclusion, when measuring nasal resistance in SAS patients, the supine position which is closer to sleeping condition, may be more suitable than upright.
