Role of ultrasonography in assessment of anatomic upper airway changes in patients with obstructive sleep apnea

Abstract

Instroduction: Obstructive sleep apnea is a common disorder, characterized by recurrent narrowing and closure of the upper airway accompanied by intermittent oxyhemoglobin desaturation and sympathetic activation. Ultrasound imaging of the airways has advantages of being safe, quick, repeatable, portable and widely available. Airway ultrasound can visualize and assess the mouth and tongue, oropharynx, hypopharynx, epiglottis, larynx, vocal cords, cricothyroid membrane, cricoid cartilage, trachea, and cervical esophagus.

Material and methods: This study assessed the role of ultrasonography in detecting the level and degree of obstruction of airway passages in patients with obstructive sleep apnea (OSA) and its relation to OSA severity. It included thirty-three patients diagnosed as OSA, and ten healthy subjects as a control group. All participants were ≥ 18 years and were subjected to full medical history, Epworth sleepiness score (ESS), thorough clinical examination, complete overnight polysomnography and neck ultrasonography.

Results: Ultrasonography findings showed a statistically significant increase in lateral parapharyngeal wall thickness (LPWT) (P < 0.001) and a significant increase in distance between lingual arteries (DLA) (P < 0.01) among OSA patients. Moreover, there was a significant statistical decrease in the retropalatal pharynx transverse diameter (RPD) (P < 0.05) in the OSA group compared to those without OSA. LPWT and DLA are parameters that can be used to predict the severity of OSA. Combination of LPWT and RPD can achieve a 100% sensitivity and specificity.

Conclusions: Ultrasound is more objective and convenient than the questionnaire because it doesn't require overnight time consumption. It is also more relevant than pulse oximetry for examining pharyngeal airspace. Also, this study demonstrated that submental ultrasonography is sufficiently sensitive for differentiating OSA severity.

Keywords: neck ultrasonography; obstructive sleep apnea; upper airway anatomy.