911, cpr instructions and open wounds

Hi everyone,

maybe this topic has already been addressed somewhere but I can't find the definitive answer I'm looking for... and maybe my question is silly. I hope it's not !

Here it is..

When someone is badly injured, loosing a lot of blood with open wounds, does it really make sense to perform CPR on them ? Or does doing so could be harmful ?

I am under the impression that performing CPR in such situations could maybe contribute to a fatal loss of blood.

Maybe I am totally wrong here. ( ?)

But if I am not, why does 911 seem to ALWAYS give the instruction to perform CPR on every unconscious victim(s) while waiting for the cavalry to be there, regardless of their injuries ? (At least in every 911 calls I have ever listened to, this seems to be the case...)

Thanks in advance for your answer.