Answers

Should you initiate CPR for a casualty with blast or penetrating trauma who has no pulse, respirations, or signs of life?

Resuscitation on the battlefield for victims of blast or penetrating trauma who have no pulse, no ventilations, and no other signs of life will not be successful and should not be attempted.

When should you perform a bilateral needle decompression of the chest?

Casualties with torso trauma or polytrauma who have no pulse or respirations during TFC should have bilateral needle decompression performed to ensure they do not have a tension pneumothorax.

In what circumstance might you consider CPR in the Tactical Field Care phase? 

In severe cases of hypothermia, near-drowning victims, electrocution, or other non-traumatic instances of cardiac arrest.