Catheter flushing is a routine procedure involving the manual injection of a solution, typically sterile normal saline, through a catheter line. This action clears the internal passage of the device, ensuring it remains open and functional. Flushing is necessary for maintaining the integrity of all vascular access devices and preventing complications. It is a foundational component of catheter care that influences the safety and effectiveness of a patient’s treatment plan.
Why Catheter Flushing is Essential
Flushing is performed primarily to maintain catheter patency, meaning keeping the internal channel open and unobstructed. The flow of fluid prevents lumen occlusion caused by the buildup of blood clots, fibrin deposits, or medication precipitates. If the catheter lumen becomes blocked, it cannot be used for delivering therapy or drawing blood samples.
Flushing also prevents the mixing of incompatible substances within the catheter. Clearing residual medication or solution before, between, and after infusions reduces the risk of chemical reactions and precipitate formation. Positive pressure flushing is specifically used to prevent the backflow of blood into the catheter tip. This is achieved by clamping the line while injecting the final volume of flush solution, ensuring the catheter tip is filled with saline rather than coagulating blood.
Recommended Flushing Frequency by Device Type
The required frequency for flushing depends on the type of catheter and whether it is in continuous or intermittent use. Vascular Access Devices (VADs) require rigorous, scheduled protocols to prevent failure. For any VAD, flushing with normal saline must occur immediately before and after every use, including the administration of medications, fluids, or the withdrawal of blood samples.
Vascular Access Devices (VADs)
Central Venous Catheters (CVCs) and Peripherally Inserted Central Catheters (PICC Lines) used intermittently require a scheduled maintenance flush to ensure continued patency. When not actively used, these lines should be flushed with saline at least every 12 to 24 hours, depending on specific device and institutional guidelines. This routine clears any small amounts of blood or deposits that may have entered the lumen.
Implanted ports, a type of VAD placed completely under the skin, offer flexibility in their flushing schedule due to their design. When not in active use, implanted ports require a maintenance flush only every four weeks. After the standard saline flush, a locking solution (often low-concentration heparin or citrate) is injected into the catheter. This locking solution remains inside the lumen to prevent clots until the next use or maintenance flush.
Urinary Catheters (Foley)
The maintenance of indwelling urinary catheters, such as Foley catheters, involves an approach often termed irrigation rather than routine flushing. Unlike VADs, routine scheduled flushing or irrigation of a urinary catheter is not recommended as a standard preventative measure. Irrigation is performed only when a blockage is suspected or specifically ordered by a healthcare provider.
If a urinary catheter is not draining, manual irrigation with sterile saline may be performed to clear accumulated debris, mucus, or sediment. This is an intervention to resolve a problem, not a part of routine daily care. Frequent, unnecessary irrigation can disrupt the natural biofilm lining the catheter, potentially increasing the risk of infection.
Troubleshooting Catheter Occlusion
Despite adherence to a strict flushing schedule, a catheter may occasionally become occluded, signaled by a change in function. Common signs of a blockage include the inability to infuse fluids or medications, a high-pressure alarm on the infusion pump, or resistance when attempting to push the flush solution. For VADs, the inability to withdraw blood from the line (withdrawal occlusion) may also signal a developing clot.
If resistance is met when attempting to flush, the rule is to never force the solution. Applying excessive pressure can cause the catheter to rupture, potentially leading to serious complications like an embolism or extravasation. A healthcare professional should first check the external line for kinks or clamps obstructing the flow. Gently repositioning the patient or having them cough can sometimes dislodge a temporary obstruction.
If these steps fail to restore function, a healthcare provider must be contacted immediately. Professional intervention may involve using a specialized clot-dissolving agent, such as a thrombolytic medication like alteplase, instilled directly into the catheter lumen. This medication is left in the catheter for a prescribed period to dissolve the obstruction before attempting to flush the line again. Timely recognition and appropriate management of catheter occlusion are necessary to restoring the device’s function and ensuring safe patient care.