Pharmacology Anticoagulants #1

Question

Which laboratory values would the nurse monitor for a client receiving IV heparin?

Answers

  1. Prothrombin time (PT)
    • Rationale:

      This answer is not correct because prothrombin time (PT) is a blood test used to check the clotting time of blood for clients on warfarin therapy. This lab is monitored to assure the blood is thin enough that the client does not have clots related to their condition. The conditions treated with warfarin include atrial fibrillation and deep vein thrombosis.

  2. Activated partial thromboplastin time (aPTT)
    • Rationale:

      This answer is correct because the laboratory values for aPTT are obtained and assessed to monitor the time it takes to clot when a client is on heparin. When a client is on heparin, the time it takes to produce a clot is increased from 30-40 seconds to 60-80 seconds. A time greater than 80 seconds reflects the increased risk of bleeding or hemorrhage. If the time is <60, the client may produce a clot too quickly.

  3. International ration (INR)
    • Rationale:

      This answer is not correct because international ration (INR) is a blood test used to check the clotting time of blood for clients on warfarin therapy. This lab is monitored to assure the blood is thin enough that the client does not have clots related to their condition. The conditions treated with warfarin include atrial fibrillation and deep vein thrombosis.

  4. Potassium (K+)
    • Rationale:

      This answer is not correct because potassium (K+) levels will not need to be monitored related to heparin therapy. The normal K+ levels should be maintained to avoid electrolyte imbalance and potential cardiac arrhythmias but is not directly related with heparin therapy.

Overview

A client on heparin should be monitored carefully for bleeding. Monitoring the activated partial thromboplastin time (aPTT) is a lab that should be closely monitored and maintained at certain levels to avoid hemorrhage associated with too much heparin.

Explanation

Learning Outcomes

Heparin is an anticoagulant given intravenously or subcutaneously used to help a client not clot too much. It may be prescribed to avoid further clotting or keep a clot from becoming a deep vein thrombosis (DVT) or pulmonary embolism (PE). The blood lab of aPTT (activated partial thromboplastin time) reflects the client’s ability to clot. A typical aPTT is 30-40 seconds for a client not on heparin. When a client is on heparin, the desired level is 60-80 seconds.
The aPTT is monitored and the heparin dosage titrated to make sure the desired level is maintained. A level > 80 seconds is excessive and reflects the client has an increased risk of bleeding.

Test Taking Tip

When handwritten, the two lower case “ts” or “tt” can look like an uppercase H, to remind the student that aPTT is associated with “H”eparin therapy not PT (which does not have the two “tts” to make an H).

Video Rationale