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Thursday, 22 December 2011

Anticoagulation In Hemodialysis


Anticoagulation in Hemodialysis – MCQs


1. What is the primary purpose of anticoagulation during hemodialysis?
A. Prevent clotting in the extracorporeal circuit
B. Increase blood pressure
C. Reduce ultrafiltration rate
D. Improve dialysate flow
➡️ Answer: A. Prevent clotting in the extracorporeal circuit


2. Which anticoagulant is most commonly used during hemodialysis?
A. Heparin
B. Warfarin
C. Aspirin
D. Clopidogrel
➡️ Answer: A. Heparin


3. What is the main risk of anticoagulation during hemodialysis?
A. Bleeding complications
B. Hypotension
C. Infection
D. Electrolyte imbalance
➡️ Answer: A. Bleeding complications


4. Which type of heparin is commonly used in dialysis anticoagulation?
A. Unfractionated heparin
B. Low molecular weight heparin
C. Fondaparinux
D. Direct thrombin inhibitors
➡️ Answer: A. Unfractionated heparin


5. What is the recommended method to monitor anticoagulation during hemodialysis?
A. Activated clotting time (ACT) or clinical monitoring of bleeding and clotting
B. INR
C. Platelet count only
D. D-dimer
➡️ Answer: A. Activated clotting time (ACT) or clinical monitoring of bleeding and clotting


6. Which of the following is a contraindication to systemic heparin use in hemodialysis?
A. Active bleeding or high bleeding risk
B. Hypertension
C. Diabetes mellitus
D. Hyperkalemia
➡️ Answer: A. Active bleeding or high bleeding risk


7. What alternative anticoagulation strategy can be used in patients with high bleeding risk?
A. Regional anticoagulation with citrate or heparin-free dialysis
B. Increase heparin dose
C. Use warfarin instead
D. No dialysis
➡️ Answer: A. Regional anticoagulation with citrate or heparin-free dialysis


8. How is heparin usually administered during hemodialysis?
A. Initial bolus dose followed by continuous infusion or intermittent doses
B. Single oral dose before dialysis
C. Continuous oral administration
D. Subcutaneous injection only
➡️ Answer: A. Initial bolus dose followed by continuous infusion or intermittent doses


9. Which of the following complications can arise from inadequate anticoagulation during dialysis?
A. Clotting of the extracorporeal circuit or dialyzer
B. Hyperkalemia
C. Hypotension
D. Dialysis disequilibrium syndrome
➡️ Answer: A. Clotting of the extracorporeal circuit or dialyzer


10. What is the antidote for heparin overdose or bleeding?
A. Protamine sulfate
B. Vitamin K
C. Aspirin
D. Warfarin
➡️ Answer: A. Protamine sulfate


11. What is a common starting bolus dose of unfractionated heparin for hemodialysis?
A. 50 to 100 units/kg
B. 5000 units
C. 5 units/kg
D. 1000 units only
➡️ Answer: A. 50 to 100 units/kg


12. Which factor is a major consideration when adjusting heparin dosing during dialysis?
A. Patient’s bleeding risk and previous clotting events
B. Patient’s weight only
C. Dialysate composition
D. Dialysis machine brand
➡️ Answer: A. Patient’s bleeding risk and previous clotting events


13. What is the mechanism of action of unfractionated heparin?
A. Activates antithrombin III, which inhibits thrombin and factor Xa
B. Directly inhibits platelet aggregation
C. Blocks vitamin K-dependent clotting factors
D. Inhibits fibrinolysis
➡️ Answer: A. Activates antithrombin III, which inhibits thrombin and factor Xa


14. Which anticoagulant has a longer half-life and is sometimes used as an alternative to unfractionated heparin?
A. Low molecular weight heparin (LMWH)
B. Aspirin
C. Warfarin
D. Clopidogrel
➡️ Answer: A. Low molecular weight heparin (LMWH)


15. Why might low molecular weight heparin (LMWH) be preferred in some dialysis patients?
A. More predictable anticoagulant response and less frequent dosing
B. Cheaper than unfractionated heparin
C. No risk of bleeding
D. Oral administration possible
➡️ Answer: A. More predictable anticoagulant response and less frequent dosing


16. What is the main disadvantage of heparin-free dialysis?
A. Higher risk of clotting in the dialysis circuit
B. Increased risk of bleeding
C. Increased risk of infection
D. Lower dialysis adequacy
➡️ Answer: A. Higher risk of clotting in the dialysis circuit


17. Which of the following is NOT a common side effect of heparin?
A. Heparin-induced thrombocytopenia (HIT)
B. Bleeding
C. Hyperkalemia
D. Hypertension
➡️ Answer: D. Hypertension


18. How is heparin-induced thrombocytopenia (HIT) diagnosed?
A. Drop in platelet count >50% after heparin exposure, with or without thrombosis
B. Increased platelet count after heparin use
C. Elevated INR
D. Elevated D-dimer only
➡️ Answer: A. Drop in platelet count >50% after heparin exposure, with or without thrombosis


19. What is the management for a patient with suspected HIT?
A. Stop all heparin products and use alternative anticoagulants such as argatroban or danaparoid
B. Continue heparin and monitor platelet counts
C. Increase heparin dose
D. Start aspirin
➡️ Answer: A. Stop all heparin products and use alternative anticoagulants such as argatroban or danaparoid


20. Which of the following is a commonly used regional anticoagulation method in dialysis?
A. Citrate anticoagulation
B. Aspirin
C. Warfarin
D. Clopidogrel
➡️ Answer: A. Citrate anticoagulation


21. How does regional citrate anticoagulation work during dialysis?
A. Citrate chelates calcium, preventing clotting in the circuit, with calcium reinfused post-filter
B. Citrate inhibits vitamin K activity systemically
C. Citrate increases platelet aggregation
D. Citrate acts as a fibrinolytic agent
➡️ Answer: A. Citrate chelates calcium, preventing clotting in the circuit, with calcium reinfused post-filter


22. What laboratory parameter must be closely monitored during citrate anticoagulation?
A. Ionized calcium levels
B. Platelet count
C. INR
D. Hemoglobin
➡️ Answer: A. Ionized calcium levels


23. What is a potential complication of citrate anticoagulation?
A. Metabolic alkalosis
B. Hyperkalemia
C. Hypertension
D. Hyperglycemia
➡️ Answer: A. Metabolic alkalosis


24. In which patients is regional citrate anticoagulation particularly useful?
A. Patients with high bleeding risk
B. Patients with normal coagulation
C. Patients with hyperkalemia
D. Pediatric patients only
➡️ Answer: A. Patients with high bleeding risk


25. What is the usual route of administration for protamine sulfate in reversing heparin effects?
A. Intravenous
B. Oral
C. Subcutaneous
D. Intramuscular
➡️ Answer: A. Intravenous


26. Which statement about low molecular weight heparin (LMWH) in dialysis is TRUE?
A. It has a longer half-life and does not require continuous infusion
B. It is ineffective for dialysis anticoagulation
C. It requires routine coagulation monitoring
D. It causes more bleeding than unfractionated heparin
➡️ Answer: A. It has a longer half-life and does not require continuous infusion


27. What is the mechanism of heparin-induced thrombocytopenia (HIT)?
A. Immune-mediated platelet activation leading to thrombosis
B. Platelet destruction by the spleen
C. Excessive anticoagulation causing bleeding
D. Decreased production of platelets in bone marrow
➡️ Answer: A. Immune-mediated platelet activation leading to thrombosis


28. How soon after starting heparin therapy can HIT typically develop?
A. 5 to 10 days
B. Immediately
C. After 1 month
D. After 6 months
➡️ Answer: A. 5 to 10 days


29. Which anticoagulant is preferred for patients with a history of HIT requiring dialysis?
A. Direct thrombin inhibitors (e.g., argatroban) or danaparoid
B. Unfractionated heparin
C. Warfarin alone
D. Aspirin
➡️ Answer: A. Direct thrombin inhibitors (e.g., argatroban) or danaparoid


30. What is the main disadvantage of citrate anticoagulation?
A. Complex monitoring and risk of metabolic disturbances
B. Increased bleeding risk
C. Short half-life requiring continuous infusion
D. Ineffectiveness in preventing clotting
➡️ Answer: A. Complex monitoring and risk of metabolic disturbances

31. Which of the following is a contraindication to the use of citrate anticoagulation?
A. Severe liver failure
B. Hypertension
C. Diabetes mellitus
D. Hyperkalemia
➡️ Answer: A. Severe liver failure


32. What is the main monitoring parameter during heparin anticoagulation in hemodialysis?
A. Activated partial thromboplastin time (aPTT)
B. Prothrombin time (PT)
C. Platelet count only
D. Blood glucose
➡️ Answer: A. Activated partial thromboplastin time (aPTT)


33. What is the effect of heparin on potassium levels?
A. Can cause hyperkalemia by inhibiting aldosterone secretion
B. Causes hypokalemia
C. No effect on potassium
D. Causes hypocalcemia
➡️ Answer: A. Can cause hyperkalemia by inhibiting aldosterone secretion


34. Which of the following anticoagulants is NOT commonly used in hemodialysis?
A. Warfarin
B. Unfractionated heparin
C. Low molecular weight heparin
D. Citrate
➡️ Answer: A. Warfarin


35. What is the typical duration of action of unfractionated heparin after a bolus dose?
A. 4 hours
B. 1 hour
C. 12 hours
D. 24 hours
➡️ Answer: A. 4 hours


36. Why might heparin dosage need adjustment in patients with liver disease?
A. Reduced clearance leads to prolonged anticoagulant effect
B. Increased metabolism leads to decreased effect
C. No adjustment is needed
D. Liver disease increases platelet production
➡️ Answer: A. Reduced clearance leads to prolonged anticoagulant effect


37. Which clinical sign suggests excessive anticoagulation during hemodialysis?
A. Excessive bleeding from vascular access site
B. Hypertension
C. Muscle cramps
D. Hypokalemia
➡️ Answer: A. Excessive bleeding from vascular access site


38. What is a common cause of inadequate anticoagulation in hemodialysis?
A. Under-dosing of heparin or missed doses
B. Excessive ultrafiltration
C. Dialysate contamination
D. Patient dehydration
➡️ Answer: A. Under-dosing of heparin or missed doses


39. Which of the following is an advantage of regional anticoagulation over systemic anticoagulation?
A. Lower systemic bleeding risk
B. Easier to administer
C. No monitoring required
D. Less effective in preventing clotting
➡️ Answer: A. Lower systemic bleeding risk


40. What is the most important consideration when choosing an anticoagulation strategy for hemodialysis?
A. Balance between preventing circuit clotting and minimizing bleeding risk
B. Cost of anticoagulant
C. Patient age only
D. Duration of dialysis session only
➡️ Answer: A. Balance between preventing circuit clotting and minimizing bleeding risk


41. Which of the following is TRUE regarding heparin resistance?
A. It may require higher doses of heparin to achieve anticoagulation
B. It is caused by excessive antithrombin III activity
C. It leads to increased bleeding risk with normal heparin dose
D. It is common in patients with low platelet counts
➡️ Answer: A. It may require higher doses of heparin to achieve anticoagulation


42. What laboratory test can help diagnose heparin resistance?
A. Antithrombin III levels
B. Platelet count
C. Prothrombin time (PT)
D. Serum calcium
➡️ Answer: A. Antithrombin III levels


43. What is the mechanism by which low molecular weight heparin (LMWH) exerts its anticoagulant effect?
A. Inhibits factor Xa more selectively than thrombin
B. Inhibits vitamin K-dependent clotting factors
C. Activates plasminogen
D. Blocks platelet aggregation
➡️ Answer: A. Inhibits factor Xa more selectively than thrombin


44. Which of the following is NOT a recognized indication for heparin-free dialysis?
A. Active bleeding
B. Recent surgery
C. Severe thrombocytopenia
D. Routine maintenance dialysis without bleeding risk
➡️ Answer: D. Routine maintenance dialysis without bleeding risk


45. Which clinical monitoring parameter is most important during anticoagulation therapy in hemodialysis?
A. Signs of bleeding and clotting in the dialysis circuit
B. Blood pressure only
C. Heart rate only
D. Dialysate flow rate
➡️ Answer: A. Signs of bleeding and clotting in the dialysis circuit


46. What is the potential risk of using citrate anticoagulation in patients with impaired metabolism?
A. Citrate accumulation leading to metabolic alkalosis and hypocalcemia
B. Hyperkalemia
C. Hypertension
D. Hypoglycemia
➡️ Answer: A. Citrate accumulation leading to metabolic alkalosis and hypocalcemia


47. How is the anticoagulation effect reversed in case of heparin overdose?
A. Protamine sulfate neutralizes heparin
B. Vitamin K administration
C. Platelet transfusion
D. Aspirin administration
➡️ Answer: A. Protamine sulfate neutralizes heparin


48. Which patient factor increases the risk of bleeding during hemodialysis anticoagulation?
A. Concurrent use of antiplatelet or anticoagulant medications
B. Young age
C. High platelet count
D. Adequate nutritional status
➡️ Answer: A. Concurrent use of antiplatelet or anticoagulant medications


49. What is the typical protocol if clotting occurs in the dialysis circuit despite anticoagulation?
A. Increase anticoagulant dose and evaluate dialysis machine settings
B. Decrease anticoagulant dose
C. Stop dialysis permanently
D. Ignore and continue dialysis
➡️ Answer: A. Increase anticoagulant dose and evaluate dialysis machine settings


50. Which anticoagulant can be used in hemodialysis patients who have contraindications to heparin?
A. Direct thrombin inhibitors like argatroban
B. Warfarin only
C. Aspirin only
D. No anticoagulation options available
➡️ Answer: A. Direct thrombin inhibitors like argatroban



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