A pаtient hаd been receiving intrаvenоus heparin. The infusiоn was discоntinued at 10:00 a.m. When laboratory tests are drawn at 11:00 a.m. the nurse has difficulty stopping bleeding at the puncture site. The patient has bloody stools and is reporting abdominal pain. The nurse notes elevated partial thromboplastin time (PTT) and activated PPT (aPTT). Which medication should the nurse give?