Ultrasonographic measurement of the diaphragm thickness in patients with obstructive sleep apnea syndrome

Purpose The aim of this study was to evaluate the diaphragm thickness in patients with obstructive sleep apnea syndrome (OSAS). Methods This prospective study included patients who underwent polysomnography evaluation for the first time with a clinical suspicion of OSAS. All patients underwent polysomnographic evaluation with a 55-channel Alice 6 computerized system (Respironics; Philips, IL). Diaphragm thickness was measured as the distance between the peritoneum and the pleura using electronic calipers with a 7–12-MHz linear probe (PHILIPS EPIQ 5G). Results A total of 108 patients (67 males, 41 females) were enrolled in the current study. The mean age of the patients was 48.92 ± 11.47 years. The diaphragm thicknesses were significantly higher in OSAS patients both at end-inspirium and end-expirium compared with the normal group ( p 0.05). When the patients were allocated into OSAS subtypes; diaphragm thicknesses at the end of inspirium and expirium on both sides were significantly higher in the severe OSAS group and OSAS+OHS group compared with the other groups of normal, mild OSAS, and moderate OSAS subgroups ( p 0.05 for all). There was a positive correlation between the severity of OSAS and diaphragm thickness. Conclusion Diaphragm thickness seems to be increased in OSAS patients and the thickness correlates with the severity of OSAS. However, the thickness ratio of OSAS patients does not differ from that of normal subjects.