A client is receiving IV heparin and oral warfarin after a pulmonary embolism (PE). The nurse determines the client’s activated partial prothromboplastin time (APTT) value is two times the control value; the prothrombin time (PT) level is the same as the control, and the international normalized ratio (INR) is 1. Which protocol prescription should the nurse implement?
Reference Range:
Activated Partial Prothromboplastin Time (APTT) [Anticoagulant therapy: 1.5 to 2 times the control value in seconds.] Prothromboplastin Time (PT) [Anticoagulant therapy: greater than 1.5 to 2 times the control value.] International Normalized Ratio (INR) [0.8 to 1.1]
A.
Increase the warfarin dose.
B.
Withhold the heparin and continue the same dose of warfarin.
C.
Decrease the heparin dose.
D.
D Increase the heparin dose and decrease the warfarin dose.
The correct answer and Explanation is :
In this scenario, the most appropriate action is:
C. Decrease the heparin dose.
Explanation:
- Activated Partial Prothromboplastin Time (APTT): This test measures the efficacy of the intrinsic and common coagulation pathways, particularly the effects of heparin. The reference range for APTT during anticoagulant therapy is 1.5 to 2 times the control value. In this case, the client’s APTT is two times the control value, which falls within the therapeutic range for heparin therapy.
- Prothrombin Time (PT) and International Normalized Ratio (INR): PT measures the extrinsic and common pathways of coagulation, and INR is a standardized measure of PT. For patients on warfarin therapy, the PT/INR should be elevated. The reference range for INR is 0.8 to 1.1, which is considered normal for patients not on anticoagulants. The INR of 1 in this client indicates that the warfarin is not effectively anticoagulating the patient.
Rationale for the Answer:
- The APTT is appropriate for the current heparin therapy, so there’s no need to increase or withhold heparin. Since the INR is within the normal range (1.0), the warfarin therapy is not sufficiently anticoagulating the client, suggesting that the dosage of warfarin may need adjustment. However, the immediate concern is the heparin therapy, where the APTT indicates that the heparin effect is sufficient but not excessive.
- Decreasing the heparin dose (Option C) is necessary to prevent potential bleeding complications due to excessive anticoagulation, as the APTT is at the upper limit of the therapeutic range. It’s crucial to balance the anticoagulation to avoid both under- and over-anticoagulation.
- Increasing the heparin dose (Option D) would further increase the risk of bleeding, while withholding heparin (Option B) may result in insufficient anticoagulation. Increasing the warfarin dose (Option A) might be necessary eventually but does not directly address the immediate need to adjust heparin therapy.
Therefore, in response to the current lab values and therapeutic ranges, decreasing the heparin dose is the most appropriate immediate action.