Submental and neck ultrasonography measurements in patients with obstructive sleep apnea

Abstract Introduction: Obstructive sleep apnea syndrome (OSAS) is based on clinical symptoms and apnea-hypopnea events measured by cardiorespiratory polysomnography (PSG) that often has limited availability. Sub-mental (SM) and lateral parapharyngeal wall thickness (LPWT) ultrasound measures (UM) can discriminate the severity of OSA in Chinese patients (Shu C-C. Plos One 2013; 8(5):e62848), (Liu HK. Sleep 2007;30(11):1503-1508). Aim: The principal aim of this study was to correlate UM with OSAS severity and to assess the intra- and interobserver reproducibility of UM. Methods: Eleven caucasian patients with referred symptoms suggesting OSAS were enrolled. Two blinded pulmonologists performed UM in supine position awake patient using a convex probe: bi-LPWT on the lateral neck region, retroglossal (RG) and retropalatal (RP) transverse diameter, tongue thickness (TT) and upper airway length (UAL) on the SM region. After UM, subjects underwent to home PSG. Patients with indication to CPAP treatment performed a 7 days trial with auto-CPAP before a titration PSG. Results: OSAS was diagnosed in all patients: 3 (27%) mild, 3 (27%) moderate, 5 (45%) severe. Apnea-hypopnea index (AHI) was 30 ± 24 (mean ± s.d.). There was a low negative correlation between AHI and TT (r =-0.3), AHI and UAL (r=-0.2) (p<0.05). Mean coefficients of variance intraobserver and interobserver for UM were 0.02. In four patients treated with CPAP the selected pressure of CPAP correlated with TT (r=0.8), UAL (r=0.9), and LPWT (r=0.9) (p<0.01). Conclusion: These preliminary data suggest that UM are a reproducible, repeatable and easy accessible technique. UAL, TT and LPWT can be useful measurements useful to predict CPAP titration values.