CO2 is an oderless colourless gas, these are animals that crush their prey's internal organs t kill them, pressing all the air out of their lungs, when the heart stops pumping and the muscles stop contracting to bring blood in the veins back to the heart, there will be no addition of CO2 in the lungs, the CO2 will build in the cells and quite possibly cause cell death as they form carbonic acid.

I'd love to see information supporting your statement, because it seems quite interesting, and I'll ask my Biology Professor about all this on Monday, but in all my reading and class time, I've not heard anything to support this.