Proning, or lying a patient face down on one’s chest and abdomen (prone) as compared with lying on one’s back (supine), improves the transfer of oxygen from the lungs into the bloodstream and eventually throughout the body’s organs. Alveoli are the tiny air sacs within the lungs that permit the exchange of oxygen, carbon dioxide and other gases. Prone positioning helps keep more alveoli open and more evenly distributed at the end of expiration, thus improving gas exchange and minimizing ventilator induced damage to the lungs.