A peripherally inserted central catheter (PICC line) is a thin, flexible tube inserted into a vein in the upper arm. It is threaded until its tip rests in the large central veins near the heart, typically the superior vena cava. This central venous access is used for long-term intravenous therapies, such as extended antibiotic courses, chemotherapy, or total parenteral nutrition. The ability to draw blood back from the catheter—known as “blood return”—is a standard measure of its reliability and proper functioning. When blood return is absent, it signals a potential problem with the line’s function or position, prompting an immediate safety concern before any medication is administered.
The Significance of Blood Return
The presence of a swift, easy blood return confirms that the PICC line’s tip is correctly situated in the central circulation, typically the superior vena cava. This placement allows for the rapid dilution of infused medications. Blood return also verifies that the catheter lumen is open, or patent, and not completely blocked by a clot or precipitate. A patent line flushes and aspirates freely without resistance.
Without confirmation of blood aspiration, healthcare providers cannot be certain of the catheter tip’s exact location or the absence of a blockage. A PICC line that flushes easily but does not yield a blood return indicates a partial obstruction, known as persistent withdrawal occlusion. This partial blockage allows fluid to be pushed out but prevents the aspiration of blood, raising the risk of complications.
When a PICC Line Lacks Blood Return: Safety Protocols
Whether a PICC line can be used when blood return is absent is generally answered with caution, especially for certain medications. Standard medical protocol dictates that all infusions, particularly those containing vesicant drugs like chemotherapy agents, should be immediately held. Vesicant medications can cause severe tissue damage if they leak outside the vein, a complication called extravasation. If the catheter tip has migrated or is lodged against the vessel wall, an infusion could lead to extravasation.
If a PICC line cannot produce a blood return, its position is unconfirmed, making the use of high-risk infusions unsafe. Immediate steps involve stopping the current infusion and notifying the healthcare team. The issue is then systematically troubleshot, starting with gentle aspiration attempts using a 10 mL or larger syringe to avoid excessive pressure.
Identifying the Reason for Absent Blood Return
Absent blood return can stem from several mechanical or physiological issues. The most common cause is a thrombus, or blood clot, which forms either within the catheter lumen or on the outside of the catheter tip. This clotting prevents the aspiration of blood, even if the line still accepts a flush.
Another frequent problem is catheter malposition or migration, where the tip has moved from its intended location in the superior vena cava. Movements like coughing or strenuous activity can cause the line to migrate, sometimes pulling the tip back into a smaller vein or pushing it against the vessel wall. This movement creates a one-way valve effect.
A fibrin sheath can also form around the exterior of the catheter tip, creating a sleeve of protein that acts like a one-way flap. This sheath allows fluid to flow out during an infusion but collapses inward when negative pressure is applied during aspiration. This specific partial blockage is a common reason a PICC line will flush easily but fail to produce a blood return.
Restoring Functionality: Interventions and Next Steps
Restoring function to a PICC line that lacks blood return begins with simple, mechanical adjustments to rule out positional issues. The patient may be asked to change position, such as raising the arm or coughing, as these actions can sometimes shift a catheter tip lying against a vessel wall. If these simple maneuvers restore blood return, the issue was likely positional.
If mechanical adjustments fail, the next step involves pharmacological intervention to treat a suspected clot. Specialized nurses or physicians may instill a thrombolytic agent, such as alteplase, directly into the affected lumen to dissolve the blood clot. This process, known as chemical declotting, requires the agent to “dwell” in the catheter for a set period before aspiration is attempted again.
If the line remains non-functional after these interventions, further imaging, like a chest X-ray, may be required to confirm the catheter’s tip position. If all attempts to restore patency fail, the line is deemed non-functional and may need to be removed and replaced.