The statement is true. Atelectasis is the collapse or closure of a lung resulting in reduced or absent gas exchange. It may effect part or all of a lung. An airway blockage also can cause Atelectasis. A blockage may be due to a foreign object, a mucus plug, lung cancer, or a poorly placed breathing tube from a ventilator. When a blockage occurs, the air that's already in the air sacs is absorbed into the bloodstream.