Fig. (2) (a-b) The diameter measurement and PSV recorded in CA (note: located at 3.98cm depth from surface) in one of the subject’s in group A with BMI=20.81kg/m², in supine position and during expiration phase [diameter =6.7mm and PSV=109.4cm/s]; and (c-d) The diameter measurement and PSV recorded in CA (note: located at 7.85cm depth from surface) in one of the subject’s in group B with BMI= 28.52 kg/m², in supine position and during expiration phase [diameter =8mm and PSV=88.9cm/s].