Think about this, hypocarbia takes place when we hyperventilate since the CO2 levels in our blood decreases and more O2 levels on the other hand. CO2 is not just merely a gaseous waste. It actually stimulates us to breathe. The moment that our body senses that this gas is below the normal, we compensate through breathing fast. You could be hyperventilated too upon receiving oxygenation therapy which is not closely monitored.