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CVC Fibrin Sheath — FRCA Final MCQ

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ModerateIntensive Care MedicineCVC Fibrin SheathFRCA Final

A 40-year-old man on ICU has a right internal jugular central line. The CXR confirms correct tip position. On day 5, the line develops a persistent blood return on aspiration but infusion is sluggish. Flushing meets resistance. What is the most likely cause?

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Correct answer: B — Catheter tip thrombus or fibrin sheath

Catheter-related thrombosis (tip thrombus or fibrin sheath) is the most common cause of sluggish infusion with preserved blood aspiration in a central line that was previously functioning normally. The fibrin sheath forms around the catheter and acts as a one-way valve, allowing blood return on aspiration but creating resistance to infusion. Management: attempt gentle flushing with saline, consider alteplase (TPA) lock protocol (1-2 mg in 2 mL instilled into the catheter for 30-120 minutes), and if unsuccessful, consider catheter exchange over a guidewire or new site insertion.

Reference: NICE – 2017 – CG139 CVC management; ICS – 2023 – Vascular access standards