An implanted port (Port-a-Cath) is a small medical device placed under the skin, providing long-term access to a large vein for treatments like chemotherapy or intravenous fluids. The port is accessed using a Huber needle, a specialized, non-coring needle with a blunted tip. This design pushes aside the silicone septum rather than cutting it, allowing the septum to reseal after removal. The duration a Huber needle can safely remain in the port—known as the dwell time—is a safety consideration for patients receiving continuous or frequent treatments.
Standard Clinical Limits for Dwell Time
The maximum time a Huber needle can stay in an implanted port is guided by infection control and device integrity standards. Most institutional guidelines and current clinical standards, such as those from the Infusion Nurses Society (INS), recommend changing the needle and the accompanying dressing at least every seven days. This seven-day limit is widely adopted across healthcare settings to minimize the risk of complications, including infection and skin irritation.
The rationale for this time constraint centers on the physical interaction between the needle, the skin, and the port septum. Over several days, the presence of the steel needle creates friction against the skin at the puncture site, increasing the likelihood of local infection. Furthermore, prolonged dwell time can compromise the sterile dressing, which provides a protective barrier against external contaminants.
While some older clinical studies have explored extended dwell times, sometimes up to 28 days, these are not the current standard of care. The seven-day standard balances patient comfort with maintaining a sterile access site and preventing needle-related complications. Adherence to this institutional policy is paramount, even for continuous infusion protocols, as the needle itself is the limiting factor for dwell time.
Signs and Circumstances Requiring Immediate Removal
Although the standard dwell time is seven days, the Huber needle must be removed immediately if any adverse signs or complications arise. Localized signs of infection include new or increasing redness, swelling, unusual warmth, or purulent drainage around the needle. Experiencing pain, burning, or stinging at the site, especially during an infusion, can signal extravasation, where medication is leaking into the surrounding tissue instead of the vein.
Malfunction of the needle or port system is another cause for urgent removal. This includes the inability to flush the line freely or to withdraw blood, suggesting an occlusion or blockage within the port or catheter. If the needle has partially withdrawn, become dislodged from the septum, or if there is leakage of fluid around the site, the access is compromised and must be discontinued.
Systemic symptoms, such as unexplained fever or chills, suggest a potential bloodstream infection. This is a life-threatening complication requiring immediate investigation and removal of the access device. These signs of infection or mechanical failure take precedence over the planned dwell time and necessitate immediate medical attention to prevent further harm.
Maintaining the Access Site During Extended Dwell
For the Huber needle to remain safely in place for the maximum allowed dwell time, routine maintenance protocols must be followed. The transparent dressing covering the needle and access site must be changed at least every seven days as part of infection prevention. If the dressing becomes soiled, wet, or non-intact before the seven-day limit, it must be replaced immediately using sterile technique.
Proper flushing is necessary to maintain the patency of the port and prevent blood clots from forming in the catheter. When the port is accessed but not actively used for continuous infusion, it should be flushed with saline and often locked with a heparin or citrate solution, according to facility protocol. This flushing is typically performed daily to ensure the line remains open and functional.
Upon removal of the Huber needle, a positive pressure technique is employed to prevent the reflux of blood back into the catheter tip, which can lead to occlusion. This technique involves injecting the final portion of the flush solution while simultaneously withdrawing the needle from the port. This helps to seal the catheter end and maintain long-term patency. All site care, including flushing and dressing changes, requires strict sterile technique to minimize the introduction of pathogens to the accessed port.