Rhinologic Aspects in Management of Sleep-disordered Breathing (SDB)

鄭元凱

中國醫藥學院  附設醫院耳鼻喉部

The exact role of the nasal airway in the pathobiology of SDB, especially the obstructive sleep apnea (OSA), is not clear.

Since breathing through the nose appears to be the preferred route during sleep, nasal obstruction frequently leads to nocturnal mouth breathing, snoring, and ultimately to OSA.  Reduced nasal cross-sectional area causes increased nasal resistance and obstruction, which may significantly increase the negative pressure of the upper airway and predisposes the patient to inspiratory collapse of the oropharynx, hypopharynx, or both.  Patients with discrete abnormalities of the nasal passage, such as septal deformities, nasal polyps, and choanal atresia, require correction.  Nasal mucosal conditions, such as sinusitis and inferior turbinate hypertrophy, may also reduce the nasal cross-sectional area.  These sources of obstruction are usually addressed surgically in the management of OSA in order to decrease nasal resistance and increase nasal airflow.

An obstructed nasal airway is known to be a potential contributing factor in the development of OSA.  Correction of an obstructed nasal airway should, therefore, logically aid in the treatment of OSA.  However, review of experimental reports indicates that correction of an obstructed nasal airway might not improve objective data measuring the severity of OSA.  In fact, an improved airway sometimes results in worsening the OSA.  A similar phenomenon to this rhinologic controversy was also shown by the dichotomous physiological effects of nocturnal external nasal dilation in heavy snorers.

It is worthy of mention the effects of nasal surgery in comparing polysomnograms before and after surgery, and also of reviewing the effects of an improved nasal airway on continuous positive airway pressure (CPAP) levels and compliance of CPAP use.  Most patients convey an improvement in nasal and sleep symptoms after correction of a nasal airway obstruction; however, nasal surgery alone does not consistently improve OSA when measured objectively.  Depending upon the severity of OSA, nasal airway reconstruction may contribute to a decrease in CPAP level and improvement in oxygen saturation.  Correction of the obstructed nasal airway should be included in the overall management of OSA.

Both rhinologists and allergists could also play a vital role in assessing sleep problems in patients with allergic rhinitis and other upper respiratory disorders, in treating these problems more aggressively, and in some situations, in preventing them.