In anesthetized patients the airway needs to be secured due to lack of protective reflexes. Golden standard is the endotracheal intubation. In patients undergoing lung surgery single lung ventilation is essential. In these cases a double lume tube is commonly used. The double lume tube has a proximal tracheal and a distal bronchial end reaching into the left or the right side of the lung dependant of the model of the tube. Thus it is possible to operate on one collapsed side of the lung while ventilating the other side.