Effects of Supine and Prone Positions on Nasal Patency in Healthy Individuals

Effects of sitting, supine, and prone postures on nasal patency in individuals with obstructive sleep apnea syndrome

BACKGROUND

Studies have found that in healthy individuals without nasal disease, changes in posture cause an increase in nasal resistance, especially in the prone posture. Many patients with obstructive sleep apnea syndrome (OSAS) sleep in a prone posture, but no studies have examined the effect of this change in posture on nasal resistance in patients with OSAS. Therefore, we conducted this study to investigate this posture-related physical phenomenon in individuals with OSAS.

METHODS

We evaluated the nasal patency of 29 patients diagnosed with OSAS using the visual analog scale (VAS), acoustic rhinometry, and video-endoscopy in the sitting, supine, and prone postures.

RESULTS

In the OSAS group, both supine and prone postures significantly influenced subjective nasal blockage and led to a notable reduction in the minimal cross-sectional area (mCSA) as determined by acoustic rhinometry, compared to the sitting posture. The prone posture exhibited a more pronounced effect than the supine posture. Endoscopic evaluations further revealed increased hypertrophy of the inferior turbinate in the supine posture for the right nasal passage and the prone posture for the left. However, no significant differences were observed between the prone and supine postures.

CONCLUSION

In OSAS patients, nasal resistance significantly increased in supine and prone postures compared to sitting, with the prone posture showing a greater effect. Clinicians should consider a patient's habitual sleep posture and the effects of postural changes when assessing OSAS severity and devising treatment plans.

LEVEL OF EVIDENCE: 4

Nasal Patency Measurement: State of the Art of Acoustic Rhinometry

Nasal obstruction is one of the main symptoms of different nasal pathologies. Many physiological and pathological conditions can produce nasal airflow impairment causing nasal obstruction and affecting patients' quality of life. There are different methods for the measurement of nasal obstruction, but in clinical practice the most common used are acoustic rhinometry, rhinomanometry, and peak nasal inspiratory flow. This review describes the fundamentals of acoustic rhinometry, its normal values, the different physiological and pathological conditions that can modify nasal patency, and the utility of this instrument for the measurement of nasal obstruction in clinical practice. Acoustic rhinometry is a simple test, so it is suitable for measurements in the pediatric population, i.e., for evaluating adenoid hypertrophy. Acoustic rhinometry normal values are available, unilaterally and bilaterally for pediatric and adult populations. Acoustic rhinometry has been demonstrated to be reproducible and even superior to rhinomanometry when measuring nasal modifications during challenges. It is possible to use acoustic rhinometry before and after nasal surgery. Measuring nasal cavities volume and cross-sectional area, acoustic rhinometry is particularly indicated in rhinosurgery, especially for the evaluation of spreader grafts. Brief considerations about the correlation between nasal symptoms, in particular the subjective sensation of nasal obstruction, and the acoustic rhinometry results as well as the correlation of acoustic rhinometry with other methods for the measurement of nasal obstruction are also reported. Objective and subjective evaluation of nasal obstruction gives different information that together optimizes the diagnosis and the treatment of rhinologic patients. Acoustic rhinometry alone or in combination of other instruments for the measurement of nasal obstruction or patency should be used regularly in every outpatient clinic that treats patients with nasal obstruction as there is an increasing need of evidence-based therapies.

Nasal Patency Across Seated, Supine, and Recumbent Postures in Individuals With and Without Allergic Rhinitis

Objectives: This study aimed to investigate the effects of seated, supine, and recumbent postures on nasal resistance in individuals with allergic rhinitis (AR) and healthy controls, which has not been investigated in the past. Methods: A visual analog scale (VAS) assessed subjective nasal obstruction, while acoustic rhinometry and video endoscopy provided objective measures. Sixty participants, comprising 30 AR patients and 30 healthy controls, were evaluated across 4 postures without decongestion: seated, supine, left recumbent, and right recumbent. Results: In patients with AR, we noted no significant changes in subjective nasal blockage under various postures (all P > .18). However, significant reductions of minimal cross-sectional area (mCSA) were found (seated vs supine, P = .014; seated vs left recumbent, P = .001; seated vs right recumbent, P < .001) and significant increases in the inferior turbinate hypertrophy were observed on the dependent side of the nose when in recumbent posture (right nose: seated vs right recumbent, P = .013; left nose: seated vs left recumbent, P = .003). On the contrary, healthy controls experienced increased subjective nasal obstruction (VAS scores: seated vs supine, P < .001; seated vs left recumbent, P = .003; seated vs right recumbent, P < .001), reductions in mCSA (seated vs supine, P = .002; seated vs right or left recumbent, both P = .001), and increased inferior turbinate hypertrophy on the dependent side of the nose (right nose: seated vs right recumbent, P = .003; left nose: seated vs left recumbent, P = .006). Conclusions: Healthy controls reported better nasal patency when shifting from supine or recumbent to more upright or less gravity-dependent seated postures, which was further supported by objective examinations. On the contrary, despite patients with AR not subjectively perceiving increased nasal patency while adopting more upright postures, objective evaluations demonstrated an improvement in their nasal airflow in these less gravity-dependent postures.Level of Evidence: 4.

Nasal Patency in Sitting, Supine, and Prone Positions in Individuals with and without Allergic Rhinitis

(1) Background: Physiological changes in nasal patency in response to posture contribute to sleep-related problems. Previously, we reported that the supine and prone positions cause a significant decrease in nasal patency in subjective and objective assessments of healthy individuals. Therefore, we conducted a study to evaluate the effect of posture on nasal patency in patients with allergic rhinitis (AR); (2) Methods: The present study comprised 30 patients diagnosed with AR and 30 healthy subjects without nasal disease (non-AR). Changes in nasal patency were evaluated in the sitting, supine, and prone positions. We used the visual analog scale to evaluate subjective nasal blockage. Acoustic rhinometry and endoscopy were used to objectively measure changes in nasal patency; (3) Results: In the non-AR group, the prone position had a significant effect on subjective nasal blockage compared with the sitting position, with significant decreases in the minimal cross-sectional area (mCSA) measured by acoustic rhinometry. Furthermore, endoscopy demonstrated a significantly increased inferior turbinate hypertrophy in the non-AR group. In the AR group, there was no statistical difference in subjective nasal blockage symptoms between the different positions. However, in objective examinations (acoustic rhinometry and endoscopy), the prone position showed significantly decreased nasal patency; (4) Conclusions: In patients with AR, subjective nasal blockage did not significantly increase in the supine or prone position. Endoscopy demonstrated increased inferior turbinate hypertrophy in supine and prone positions resulting in a significant reduction in nasal cavity mCSA, indicating an objective reduction in nasal patency.