CXR is good to find a simple pneumo that is not causing overt signs or symptoms.
i once heard a doctor say, "if you use a CXR to find a tension pneumo, then you're a crappy doctor." point being, a tension pneumo is a life threatening event. needle them and ask questions later.
in a traumatic PEA arrest, you need to address any potential reversible causes in the famed H's and T's. that means needles/chest tubes. pericardiocentesis is even appropriate if you think tamponade could be an issue. ultrasound can help you with determining that. if no ultrasound in your department, i think doing it when all else has failed is good. i agree with those above...PEA isn't alive. you need to pull out any trick you've got to try and get them back to a perfusing rhythm.