Final answer:
The nurse should document the patient's ruptured eardrums as Primary injuries and the traumatic injuries to the lower extremities as Secondary injuries, distinguishing the direct effects of the explosion from injuries caused by the debris.
Step-by-step explanation:
In documenting injuries sustained from a pipe bomb explosion, a nurse would classify them as either Primary or Secondary. Primary injuries are those that occur as a direct result of the explosion itself, such as the ruptured eardrums from the blast wave. Secondary injuries are caused by flying debris or shrapnel, which in this case are traumatic injuries to the patient's lower extremities. It is important that the nurse documents these clearly to ensure that the patient receives appropriate care and these details can also be useful in legal and insurance proceedings stemming from the incident.