Daniel Lichtenstein is medical intensivist, visiting Professor, working since 1989 at François Jardin’s medical I.C.U. He defined in 1991 critical ultrasound as a holistic approach to the critically ill. This definition includes the whole body, mainly centered around the lung. Lung ultrasound is used for diagnosing acute respiratory (BLUE-protocol) and circulatory failure (FALLS-protocol) and cardiac arrest (SESAME-protocol). It includes procedures (thoracentesis, venous line insertions, …). Six textbooks (last Edition, Lung Ultrasound in the Critically Ill, 2015, Springer-Verlag), two dozens of original articles (critical, venous and lung ultrasound). President of CEURF, an international training center with personnalized training at the bedside.