A Peripherally Inserted Central Catheter (PICC line) is a thin, flexible tube inserted into a vein in the arm, with its tip resting in a large vein near the heart. This device provides safe, long-term access for administering medications, fluids, and drawing blood. Because the catheter remains in place for an extended period, careful maintenance is required to prevent complications. The primary maintenance method is flushing, which involves injecting a specific solution designed to keep the catheter clear and infection-free.
Why Routine Flushing Is Essential
Routine flushing maintains the catheter’s patency (unobstructed state). Without flushing, residue from medications, blood components, or fluids can accumulate on the inner walls, leading to an occlusion. This blockage can make the line unusable, often requiring replacement. The mechanical action of flushing clears this buildup, ensuring the line remains open. Flushing also prevents stagnant fluids within the catheter’s lumen from becoming a breeding ground for microorganisms. Regularly exchanging the fluid reduces the risk of bacteria accumulating and causing a dangerous bloodstream infection. This maintenance is essential because the PICC line tip sits directly in the central circulation, meaning any contaminants are immediately introduced into the body’s main blood flow.
Primary Flushing Agent: Sterile Saline
The universal, first-line agent for flushing a PICC line is 0.9% normal saline, a sterile solution of sodium chloride in water. This solution is biologically neutral, compatible with the human body, and does not interact with most medications or cause irritation to the vein. A volume of 10 milliliters is typically used for a single flush in adults. Saline is used immediately before and after the administration of any substance, such as medication or intravenous fluids, to clear the line. Flushing before administration ensures the medication does not interact with any residual substance. Flushing afterward removes the medication completely, preventing precipitation or residue buildup that could lead to occlusion. For maintenance flushes, saline alone is often sufficient to maintain patency.
Specialized Flushing Agent: Heparin
A secondary agent used in addition to saline is Heparin, a medication that acts as an anticoagulant, or blood thinner. Heparin is used to “lock” the line; it is left inside the catheter to prevent the formation of blood clots at the tip. This is relevant when a PICC line is dormant for more than 12 to 24 hours. The concentration of Heparin used for locking is very low, typically 10 units per milliliter (U/mL), far lower than what is used for therapeutic blood thinning. The decision to use a Heparin lock is determined by the specific type of catheter and the healthcare provider’s protocol, as some newer valved catheters are designed to be saline-only. Using Heparin requires careful adherence to dosage and concentration instructions to maximize its anti-clotting effect.
Flushing Schedule and Technique
The frequency of flushing is determined by the line’s usage, but a maintenance flush is generally required at least every 12 to 24 hours when the line is idle. The flushing technique involves a specific maneuver known as the “push-pause” method. This technique involves injecting the solution in short, brisk bursts, pausing briefly between each one, rather than a single, continuous flow. The push-pause action creates a turbulent flow within the catheter’s lumen, which is effective at dislodging adherent debris and residue from the catheter walls. The last step of the flush often involves maintaining a positive pressure lock, achieved by clamping the line or disconnecting the syringe while still injecting the final milliliter of fluid. This maneuver helps prevent blood from flowing backward into the catheter tip, a common cause of clot formation and subsequent occlusion. Pre-filled, single-use syringes are routinely used for flushing to ensure precise dosage and maintain sterility.