A port flush is a maintenance procedure for an implanted vascular access device (VAD), specifically a port, designed to ensure the device remains clear and functional. This routine care involves injecting a specific solution into the port to prevent the buildup of materials that could cause a blockage. Performing a port flush is a necessary step to maintain the long-term usability of the implanted device for safely delivering medications or drawing blood samples. The process is a highly important component of care for people utilizing this type of medical technology.
Understanding Vascular Access Ports
A vascular access port is a medical device implanted entirely beneath the skin to provide long-term, easy access to a patient’s bloodstream. The device consists of two main parts: a reservoir, or port body, and a catheter. The reservoir is typically a small, quarter-sized chamber with a self-sealing silicone top, called a septum, which sits just under the skin of the chest.
The catheter is a thin, flexible tube attached to the reservoir that is surgically threaded into a large central vein, often the superior vena cava near the heart. Because the entire system is implanted, there is no external tubing when the port is not in use, lowering the risk of infection compared to external lines. When access is needed, a special non-coring needle is inserted through the skin and into the port’s septum, allowing for repeated use.
The Purpose of Port Flushing
The primary reason for performing a port flush is to maintain the patency of the catheter, meaning keeping it open and free from internal blockage, or occlusion. When the port is used for infusions or blood draws, trace amounts of blood or medication residue can remain inside the catheter and reservoir. If these materials are allowed to remain stagnant, they can begin to clot.
A concern is the formation of a fibrin sheath, a layer of blood protein that can wrap around the catheter tip and inner wall. This sheath can act like a valve, allowing fluids to be pushed into the vein but preventing blood from being withdrawn. Regular flushing cleans the internal surfaces of the device, effectively pushing out residual blood components or drugs before they can form a clot or biofilm.
The Port Flushing Procedure
The port flushing procedure must be performed using sterile technique to prevent introducing bacteria into the bloodstream. A healthcare professional first accesses the port by inserting a specialized, non-coring needle through the skin and into the self-sealing septum of the reservoir.
The technique involves first confirming the needle is correctly placed by gently drawing back to ensure there is blood return into the syringe. A syringe containing sterile normal saline (0.9% sodium chloride) is then used to flush the port. The recommended technique is often the “push-pause” method, which involves injecting the saline in short, quick bursts rather than a continuous stream. This turbulent flow creates a swirling action inside the catheter, which is more effective at dislodging material adhering to the catheter walls.
Following the saline flush, a locking solution is typically administered to maintain patency until the next use. Traditionally, this has been a diluted dose of heparin, an anticoagulant, used to “lock” the port and prevent clotting in the catheter tip. In some cases, a simple saline lock may be used instead of heparin. The final step, known as positive pressure technique, involves injecting the last portion of the locking solution while simultaneously removing the needle, which helps prevent blood from flowing back into the catheter tip as the pressure normalizes.
Maintaining the Port and Recognizing Issues
For ports that are not in active use, a routine maintenance flush is necessary to prevent clotting and keep the device ready for use. The generally accepted standard for an inactive port is to perform a flush every four weeks, although some studies suggest that extending this interval may be safe for certain patients. Adhering to the recommended schedule is important for preventing occlusions, which can lead to the need for clot-dissolving medications or, in severe cases, port replacement.
Despite regular maintenance, complications can still occur, and recognizing the signs of trouble is important for patients and caregivers. A common issue is the inability to withdraw blood, or difficulty flushing the line, which may indicate a clot or fibrin sheath formation. Signs of infection around the port site include:
- Redness.
- Swelling.
- Increased warmth.
- Tenderness.
- Pus formation.
If any of these symptoms appear, or if a fever develops, a healthcare provider should be contacted immediately, as prompt intervention is required to manage any potential infection or device malfunction.