Ultrasonographic assessment of diaphragmatic contraction and relaxation properties: correlations of diaphragmatic displacement with oesophageal and transdiaphragmatic pressure oleh Dimitrios Matamis, Savvoula Savvidou, Entela Koco, Matthew Tsagourias, Eleni Soilemezi, Panagiota Sotiriou, Ioannis Pnevmatikos