Abstract
BACKGROUND. Positive posture reaction is a common concern in obstructive sleep apnea (OSA) patients, which affects both their sleep quality and overall health-related quality of life. Rhinomanometry has been used as a functional test to assess nasal airway resistance (NAR) and measure nasal airflow (NAF).
OBJECTIVE. We conducted this study using 4-phase positional rhinomanometry (4PPR) to investigate potential correlations between NAR and NAF when comparing the sitting and supine positions through the use of 4PPR.
MATERIAL AND METHODS. This cross-sectional study involved a consecutive group of adult patients (n=115) diagnosed with OSA, aged 18 to 60 years. 4PPR evaluation was conducted in accordance with consensus guidelines. The assessments were carried out in both the sitting position and after 10 minutes in the supine position. Correlation and comparative analyses were conducted using Pearson correlation, Spear-man rank correlation, paired t-tests, and the Kruskal-Wallis test.
RESULTS. A statistically significant increase in total NAR (mean difference: +0.09 Pa/cm³/sec, p=0.048) and a significant decrease in total NAF (mean difference: -52.1 mL/sec, p=0.001) were observed during the transition from sitting to supine. Subgroup analysis revealed a significant rise in NAR for the right nasal cavity (p=0.0001), while the left side showed a non-significant increase (p=0.114). Both nostrils showed significant reductions in NAF (right: p=0.001, left: p=0.000). Classification of nasal obstruction based on sitting NAR and NAF indicated that patients with higher baseline NAR showed greater sensitivity to positional changes (Spearman’s ρ = -0.42, p<0.001). Conversely, changes in NAF were less dependent on baseline airflow (ρ = -0.15, p=0.12), suggesting alternative influencing factors.
CONCLUSION. From our observations, it is clearly evident that the total nasal airway resistance increases, and the nasal airflow reduces on lying down, the primary source of variation being the posture changing. This finding is valuable in snorers and sleep apnea patients. 4-phase positional rhinomanometry should be performed to diagnose upper airway collapse in the supine position as part of the OSA evaluation.