A 58-year-old man is hospitalized with an acute deep vein thrombosis in his right leg. He is promptly started on a continuous intravenous infusion of unfractionated heparin. The nursing staff is instructed to draw blood every six hours to adjust the infusion rate according to a standard hospital protocol. Which of the following laboratory parameters is the most appropriate to monitor and titrate this therapy?
- Activated partial thromboplastin timeCevap
- BInternational normalized ratio
- CD-dimer concentration
- DBleeding time
- EFactor VIII activity level
Cevap
Activated partial thromboplastin time is the standard parameter used to monitor and titrate continuous unfractionated heparin infusions.
The correct answer is activated partial thromboplastin time. Unfractionated heparin exerts its anticoagulant effect by binding to and potentiating antithrombin, which rapidly inactivates thrombin (factor IIa) and factor Xa, as well as other intrinsic pathway factors. Because its most pronounced effect is on the intrinsic coagulation pathway, the activated partial thromboplastin time is the standard, widely available laboratory parameter used to safely monitor its anticoagulant effect and dictate titration of the continuous infusion rate.
Adım Adım Çözüm
Anahtar Kavram
Monitoring continuous unfractionated heparin therapy requires serial measurement of the activated partial thromboplastin time to ensure therapeutic efficacy and minimize hemorrhage risk.
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