All living cells in our body need oxygen to survive, as the oxidative metabolism converts oxygen into usable energy. In our circulatory system blood, in particular hemoglobin, is transmitting oxygen to all the tissues in our body. Some tissues can survive for a brief interruption of oxygen flow. Others, especially the brain and our nervous system, die rapidly without any continuous oxygen flow. This is also the reason why we should administer oxygen to any pressure related or barotrauma injury.