Usage of four-phase high-resolution rhinomanometry and measurement of nasal resistance in sleep-disordered breathing.
OBJECTIVE
To investigate the ease of use of four-phase high-resolution rhinomanometry (HRR), a new way of measuring nasal resistance, in measuring change in nasal resistance from supine to inclined position in a clinical sleep laboratory setting, and to correlate findings with continuous positive airway pressure (CPAP) tolerance.


METHODS
Retrospective review of clinical charts.


METHODS
Forty successively seen Caucasian subjects diagnosed with sleep-disordered breathing (SDB) with complete charts were analyzed. Using four-phase HRR and acoustic rhinometry, nasal resistance and minimal cross-sectional area of the nasal cavity were objectively measured with the patient in the supine position and repeated in the inclined position (30° from the horizontal plane), respectively.


RESULTS
From the supine to inclined position, reduction in total nasal resistance was observed in 87.5% (35 out of 40). There was a mean reduction of nasal resistance by 37.1 ± 21.6%. Five (12.5%) out of 40 subjects showed no change or mild increase in nasal resistance. Subjects with nasal resistance unresponsive to the inclined position change tended to have difficulty using nasal CPAP based on downloaded compliance card data.


CONCLUSIONS
Four-phase HRR and acoustic rhinometry are tests that can be easily performed by sleep specialists to characterize nasal resistance in SDB patients and determine changes in resistance with positional changes. In this study, we found that patients who did not demonstrate a decrease in nasal resistance with inclined position were more likely to be noncompliant with nasal CPAP. These measurements may help us objectively identify patients who might have trouble tolerating nasal CPAP.
Stanford University Sleep Medicine Division, Stanford University School of Medicine, Stanford, California 94063, USA.
Song-Tar
ST
Toh
Cheng-Hui
CH
Lin
Christian
C
Guilleminault
D000293:Adolescent; D000328:Adult; D000368:Aged; D000403:Airway Resistance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity / Q000473:pathology / Q000503:physiopathology; D015508:Nasal Obstruction / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D009668:Nose Diseases / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D012189:Retrospective Studies; D025363:Rhinomanometry / Q000379:methods*; D012891:Sleep Apnea Syndromes / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D055815:Young Adult