During hemodialysis, which of the following drugs is used to prevent blood clotting?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Pharmacology

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Explanation

Heparin is the standard anticoagulant used during hemodialysis to prevent blood from clotting in the extracorporeal circuit (tubing and dialyzer).
It works by binding to and activating antithrombin III, which in turn inactivates thrombin and Factor Xa, key components of the clotting cascade.
Heparin is preferred for this purpose due to its rapid onset, short half-life, and the existence of a specific antidote (protamine sulfate), allowing for controlled anticoagulation during the procedure.

Option A: Protamine is not an anticoagulant; it is the antidote for heparin. It binds to heparin to neutralize its anticoagulant effect.
Option C: Warfarin is an oral anticoagulant with a slow onset of action (taking several days to become therapeutic). It is unsuitable for the acute, immediate anticoagulation needed for a hemodialysis session.
Option D: Aspirin is an antiplatelet drug, not a primary anticoagulant. It inhibits platelet aggregation, which is a different part of hemostasis. While it affects clotting, it is not sufficient to prevent clotting in the dialysis circuit.

Clinical Relevance

Nursing practice connection: Knowing Pharmacology of Anticoagulation in Hemodialysis helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses must meticulously monitor the hemodialysis circuit for signs of clotting (dark streaks, high pressures) and the patient for signs of bleeding (oozing from access site, hypotension, tachycardia), as these are the primary complications of heparin therapy.
The heparin dose must be individualized and may require adjustment based on lab values (aPTT), patient weight, and previous dialysis responses to prevent complications.
What if? If a patient has a history of Heparin-Induced Thrombocytopenia (HIT), heparin is contraindicated. The nurse would anticipate using an alternative anticoagulant like argatroban or regional citrate anticoagulation.

How to Approach the Question

First, identify the core of the question: it asks for the drug used to prevent clotting during the specific procedure of hemodialysis.
Analyze the keywords: 'hemodialysis' and 'prevent blood clotting'. This points to the need for a rapid-acting, short-term anticoagulant.
Evaluate the options based on their primary mechanism and use case.
Recall that Heparin is the classic, fast-acting injectable anticoagulant used in hospital procedures.
Contrast this with Warfarin (slow, oral, long-term), Aspirin (antiplatelet), and Protamine (a reversal agent, not an anticoagulant).
This systematic elimination based on drug class and clinical application leads to Heparin as the only logical answer.

Concept Tested & Keywords

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E6 Pharmacology Nursing Lilley 11e Part 2 pp. 112-114, 127-129

E6 Physiology Essentials Sembulingam 10e Part 1 p. 140-142