Outcome of nasal measurements in patients with OSA - Mounting evidence of a nasal endotype.

BACKGROUND

Increased nasal resistance as measured by 4-phase rhinomanometry is associated with a paucity of apneas relative to hypopneas in obstructive sleep apnea (OSA) patients. The ratio of hypopneas to apneas for a given apnea hypopnea index (AHI) may influence treatment choice. This study aimed to investigate if OSA patients with an elevated hypopnea apnea ratio are associated with differences in acoustic rhinometry measurements.

METHODS

One hundred and thirty-nine (n = 139) OSA patients (AHI >5) were enrolled in this prospective case-control study (all male). OSA Diagnosis was established through a type three sleep study. Both acoustic rhinometry and 4-phase rhinomanometry were performed on all patients at baseline and after decongestion. Possible associations between apnea-hypopnea index, oxygen desaturation index, nadir oxygen saturation, apnea index, hypopnea index, hypopnea to apnea ratio and body mass index and were analysed using multiple logistic and linear regression models.

RESULTS

The acoustic rhinometry measurements minimal cross-sectional area, total volume and minimal cross-sectional areas are significantly smaller in patients with increased nasal resistance as measured by 4-phase rhinomanometry (P < 0.01). No consistent statistically significant associations were found between the acoustic rhinometry variables, and the respiratory variables analysed in the sleep studies. OSA patients with an elevated hypopnea apnea ratio are more than 4 times more likely to present with increased nasal resistance measured by 4-phase rhinomanometry (OR = 4.4, 95% CI [1.5-13.2], P < 0.01).

CONCLUSIONS

Acoustic rhinometry is significantly associated with 4-phase rhinomanometry. However, acoustic rhinometry measurements are not associated with the respiratory indices routinely measured in OSA in a clinical setting. 4-phase rhinomanometry is a more suitable method for detecting clinically relevant nasal obstruction in obstructive sleep apnea patients.