It’s because there’s still enough oxygen in the blood to keep the brain alive for quite a while, so long as you can keep moving different blood to the brain. The brain is what kills you and what needs the most oxygen, so just cycling the blood that’s there will keep it from dying for quite a while.
From what I understand, chest compressions move the lungs enough to equate to shallow breathing (as long as the airway is clear)
It’s because there’s still enough oxygen in the blood to keep the brain alive for quite a while, so long as you can keep moving different blood to the brain. The brain is what kills you and what needs the most oxygen, so just cycling the blood that’s there will keep it from dying for quite a while.