A 68-year-old client receiving a heparin infusion for deep vein thrombosis reports sudden onset of severe low back pain and has become increasingly restless over the last 30 minutes. The nurse notes the client's blood pressure is 88/52 mmHg, heart rate is 118 beats/minute, and the most recent aPTT result is 142 seconds (therapeutic range 60–100 seconds). Which action should the nurse take first?
- Recheck the aPTT in one hour and reduce the heparin infusion rate by 25%
- Notify the primary health care provider and stop the heparin infusion immediately
- Administer protamine sulfate as ordered and stop the heparin infusion
- Place the client in Trendelenburg position and increase the IV fluid rate