Ultrasound parameters linked with severe sleep apnea

Anatomical markers visualized on ultrasound could have clinical utility in classifying severity of sleep apnea, a new study shows. 

While other imaging modalities are capable of imaging the area of interest in sleep apnea patients, ultrasound has taken on an increasingly prevalent role in visualizing oropharynx soft structures due to its accessibility and non-invasive nature. A new study published in Clinical Radiology recently touted the efficacy of ultrasound in diagnostic processes for sleep apnea, highlighting several parameters that correlate with the severity of obstructive sleep apnea–hypopnea syndrome (OSAHS) [1]. 

“Ultrasonography may potentially provide additional information about the higher risk for OSAHS, helping to define the pathophysiology of OSAHS patients,” corresponding author S.Y. Zhu of Guangxi Medical University in China and colleagues suggested. 

Experts included 171 patients with suspected OSAHS in the study. Each patient underwent oropharyngeal ultrasound and overnight polysomnography exams, which were then compared to the patients’ apnea–hypopnea index (AHI), a commonly used method of classifying the severity of sleep apnea. For the ultrasound exams, measurements were taken at the end of expiration during normal breathing. 

Independent of age, sex and BMI, lingual height was found to have the most significant association with the patients’ AHI and was independently associated with higher risk of OSAHS. Other measures found to be relevant were maximal width of the tongue and distance from the symphysis of the mandible to the hyoid bone. Patients with the most severe OSAHS were observed to have larger oropharyngeal structures compared to those with milder degrees of severity and, in line with prior data, higher BMI was also linked with OSAHS severity.