A peripherally inserted central catheter, commonly known as a PICC line, is a thin, flexible tube inserted into a vein in the upper arm and guided into a large central vein near the heart. This device provides long-term, reliable access to the bloodstream for treatments such as extended antibiotic therapy, chemotherapy, or intravenous nutrition. Flushing is a routine procedure to maintain the catheter’s patency, preventing the accumulation of blood components, medication residue, or fibrin deposits that could otherwise lead to a blockage.
The Primary Flushing Solutions
The primary agent used to flush a PICC line is 0.9% Sodium Chloride solution, also known as normal saline (NS). This sterile, isotonic solution is compatible with the body’s fluids and is the standard choice for clearing the catheter lumen both before and after use. Its purpose is to physically wash away any remaining medication or blood components that could lead to the formation of a clot inside the line.
The volume of normal saline used for a routine flush is 10 milliliters (mL), which is sufficient to completely clear the catheter. Following the administration of thicker substances like blood or total parenteral nutrition, a larger flush volume, often 20 mL, may be required to ensure all residue is removed. Consistent use of normal saline is the most effective way to prevent catheter malfunction.
A second type of solution, an anticoagulant lock, may be used in certain situations. These locks, most commonly containing a low concentration of heparin or a citrate solution, are left inside the catheter lumen when the line is not in use for an extended period. The goal of a locking solution is to chemically prevent blood from clotting within the catheter, acting as a preventative measure against thrombotic occlusion.
The need for a heparin or citrate lock depends on the specific type of PICC line and the patient’s risk factors for clotting. Many modern PICC lines are valved and designed to minimize blood reflux, allowing normal saline to be used exclusively for both flushing and locking. Heparin locks, typically at a concentration of 10 units per mL, are reserved for open-ended catheters or for patients with a documented history of catheter blockage.
Essential Flushing Techniques and Timing
Successful flushing relies on proper technique to maintain the catheter’s internal cleanliness. The recommended method is the “push-pause” technique, which involves injecting the flush solution in short, brisk bursts, pausing briefly between each one. This turbulent flow creates a washing machine-like effect inside the catheter that is more effective at dislodging debris than a single, slow, continuous push.
The choice of syringe size is a major consideration because a smaller syringe creates more pressure on the catheter wall. To prevent excessive pressure that could damage the catheter or the blood vessel, a 10 mL syringe is the minimum size that should be used for flushing any central line, including a PICC. The final step of the flush involves maintaining a positive pressure finish as the syringe is disconnected, which prevents blood from flowing backward into the catheter tip and forming a clot.
Flushing must be performed at specific times to maximize the PICC line’s patency and safety. The catheter must be flushed immediately both before and after every use, including the administration of medications, intravenous fluids, and blood draws. For maintenance when the PICC is not actively used, a routine flush with normal saline is required at least once every 24 hours, or as frequently as every 12 hours, depending on the catheter type and protocol.
Recognizing and Addressing Complications
A PICC line that is not functioning correctly often gives immediate warning signs during the flushing process. The most common complication is catheter occlusion, which presents as resistance when attempting to flush the line. A person should never forcibly push the flush solution against resistance, as this could rupture the catheter or expel a clot into the bloodstream.
If an occlusion is suspected, the first action is to stop flushing immediately and attempt to gently aspirate a small amount of blood. The inability to withdraw blood while still being able to infuse fluid is a sign of a partial occlusion, often caused by a fibrin sheath forming over the catheter tip. If both aspiration and infusion are impossible, a total blockage is present, which requires specialized treatment with a thrombolytic agent, such as alteplase, administered by a healthcare professional.
Signs of infection, which can be local or systemic, must be monitored closely. Local infection at the insertion site may present as redness, swelling, tenderness, warmth, or discharge. Systemic infection, which is more serious, may be indicated by fever, chills, or a general feeling of being unwell. Any of these signs require immediate cessation of line use and prompt contact with a healthcare provider to prevent a bloodstream infection.