The nose isn’t often at the forefront of sleep clinicians’ minds when they think about how to best treat obstructive sleep apnea (OSA) patients, but some patient’s nasal anatomy could harbor clues about how to best care for their sleep-disordered breathing.
A filter and humidification system sitting right on the patient’s face, the nose is often considered the healthiest breathing pathway. Prior research has shown that more nasal resistance is an independent predictor for an increase in drops in oxygen saturation in OSA patients. In another study, researchers found OSA patients have restricted nasal anatomy compared to healthy controls.
Despite several studies painting a picture of how nasal anatomy may influence the manifestation of sleep-disordered breathing, the nose is often overlooked in clinical sleep medicine. The nose, we may discover, is an untapped reservoir of data that can inform precision medicine.
“Unraveling this complexity allows for a personalized medicine approach, tailoring treatment to the individual for better treatment outcomes,” wrote medical faculty at the University of Lund, Hans Christian Hoel, and his colleagues in a recent paper.
In patients who don’t adapt well to continuous airway pressure (CPAP), assessing the nose could lead to nasal-specific interventions, including surgical remedies.
The Emerging Science of Nasal Endotypes
Now, Hoel and other sleep scientists are considering if nasal endotypes, subtypes of sleep apnea characterized by a distinct pathophysiological mechanism, could one day be a useful tool in precision medicine.
Working to understand the relationship between nasal measurements and night-time breathing disruptions, Hoel and a group of researchers at the University of Lund in Sweden and at Lovisenberg Diaconal Hospital in Norway teamed up to understand the relationship between nasal measurements and OSA.
For their research, published recently in the journal Sleep Medicine, they relied on the home sleep apnea test, the Nox T3 to look at respiratory variables recorded during sleep studies in relation to rhinometry measurements.
The researchers investigated associations between acoustic rhinometry measurements and variability in breathing patterns during sleep, namely the distribution of hypopneas and apneas in OSA patients with or without nasal obstruction.
Overall, the study demonstrated that the apnea-hypopnea index, the oxygen desaturation index, or the number of apneas and hypopneas are significantly different in patients with increased nasal resistance.
Other insights from the study include:
- Apneas happen less often in OSA patients with elevated nasal resistance.
- Hypopneas occur more often in obese OSA patients.
- OSA patients with increased nasal resistance have distinct patterns of respiratory disturbance.
- It is possible to discern patients more likely to have increased nasal resistance by analyzing standard variables in sleep studies.
- 4-Phase rhinomanometry is better than acoustic rhinometry for detecting clinically significant nasal obstruction that might lead to sleep-disordered breathing.
“The clinical value of distinguishing endotypes within OSA is to illuminate that OSA severity is often multifactorial,” wrote Hoel and his colleagues in the recent paper.
Overall, while the question of how and when the nose should be considered in evaluating sleep apnea patients is compelling, more research is needed to fully understand how and if sleep medicine professionals should turn to endotypes as a tool to drive precision medicine. Patients with nasal issues can benefit from surgical interventions to help them better tolerate CPAP, or as part of a multifaceted surgical approach to OSA treatment as an alternative to CPAP. Rarely is the nose the main factor that allows effective treatment of OSA when addressed alone.
Regardless of the outcome, Nox Medical looks forward to continuing to walk beside scientists by equipping them with the diagnostic tools and accurate algorithms they need to push scientific conversations forward.
References:
Ferris B. G., Jr., Mead J., Opie L. H. Partitioning of respiratory flow resistance in man. Journal of Applied Physiology. 1964;19:653–658.
Lan MC, Lan MY, Kuan EC, Huang YC, Huang TT, Hsu YB. Nasal Obstruction as a Potential Factor Contributing to Hypoxemia in Obstructive Sleep Apnea. Nature and science of sleep. 2021;13:55-62.
Moxness MH, Bugten V, Thorstensen WM, Nordgard S, Bruskeland G. A comparison of minimal cross sectional areas, nasal volumes and peak nasal inspiratory flow between patients with obstructive sleep apnea and healthy controls. Rhinology. 2016;54(4):342-7.
Michels Dde S, Rodrigues Ada M, Nakanishi M, Sampaio AL, Venosa AR. Nasal involvement in obstructive sleep apnea syndrome. Int J Otolaryngol.
Hoel HC, Kvinnesland K, Berg S. Outcome of nasal measurements in patients with OSA – Mounting evidence of a nasal endotype. Sleep Med. 2023;103:131-137.
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