A chemotherapy port, also known as an implanted port or port-a-cath, is a small, disc-shaped device placed beneath the skin, typically in the upper chest. It connects to a catheter that threads into a large central vein. This central venous access device provides a reliable, long-term way to deliver chemotherapy drugs, fluids, and blood products directly into the bloodstream. Using a port significantly reduces the need for repeated, painful needle sticks in peripheral veins. Because the device is foreign and provides a direct path to the circulatory system, it carries an inherent risk of infection, especially in patients whose immune systems are weakened by chemotherapy.
Identifying Symptoms of a Port Infection
Recognizing the signs of a port infection quickly is important because the infection can rapidly become systemic. Localized signs occur at the site where the device is implanted or accessed. These symptoms include tenderness, increased pain, warmth, and redness (erythema) around the port pocket or along the catheter tunnel.
The presence of pus or abnormal discharge from the skin overlying the port clearly indicates a localized pocket infection. These infections often involve skin bacteria like Staphylococcus aureus and manifest with noticeable inflammation. Even without visible local signs, a systemic infection can originate from bacteria colonizing the inside of the catheter itself.
The most common systemic symptom is the abrupt onset of fever, defined as a temperature above 100.4°F (38°C), frequently accompanied by shaking chills or rigors. These signs suggest a catheter-related bloodstream infection (CRBSI). Other indications include general malaise, unexplained fatigue, and signs of severe sepsis, such as a drop in blood pressure. Any patient with a port who develops a fever or unexplained chills should immediately contact their oncology care team.
Emergency Protocol and Diagnosis
If a port infection is suspected, the patient must contact the healthcare provider or oncology team without delay. The patient should not attempt to use the port for any infusions or blood draws before medical evaluation. The diagnostic process focuses on confirming the presence of a bloodstream infection and identifying the specific organism involved to guide treatment.
The diagnosis of a CRBSI primarily relies on obtaining paired blood cultures. This involves drawing one blood sample directly through the port and another sample from a peripheral vein at the same time. If the bacterial colony count in the port sample is significantly higher—typically five to ten times greater—than the peripheral sample, the port is identified as the source.
Another technique compares the time it takes for bacteria to grow in the cultures. A positive culture result appearing hours earlier in the port sample is also suggestive of a device-related infection. Imaging, such as an ultrasound, may be used to look for fluid collection or abscess formation around the port device if a localized pocket infection is suspected.
Treatment Strategies for Infected Ports
The medical response to a confirmed port infection involves two main strategies: catheter salvage or port removal. Catheter salvage is attempted for less complicated infections and involves aggressive antimicrobial treatment aimed at clearing the bacteria while leaving the device in place. This approach typically begins with empirical, broad-spectrum intravenous antibiotics, such as vancomycin, to cover common pathogens until culture results are available.
Once the specific organism is identified, the antibiotic is narrowed to a targeted agent. A key element of salvage therapy is antibiotic lock therapy (ALT), where a high concentration of the antibiotic is instilled directly into the port and allowed to dwell for several hours daily. This process attempts to sterilize the inner surface of the catheter and disrupt the bacterial biofilm. Salvage therapy is generally pursued for 10 to 14 days, often for infections caused by certain coagulase-negative staphylococci.
Certain conditions necessitate the immediate removal of the infected port. These criteria include severe systemic symptoms, such as septic shock or hemodynamic instability, or persistent bacteremia that does not clear within 72 hours of starting appropriate intravenous antibiotics. Infection with aggressive organisms, like Staphylococcus aureus or Candida species, frequently mandates removal due to the high risk of complications.
If the infection has caused a visible pocket abscess or purulence, the port must be removed, and the wound may be left open to heal by secondary intention. Following removal, the patient continues systemic antibiotics until the infection is completely cleared. If central venous access is still required, a new port is usually implanted on the opposite side after the infection has resolved.
Reducing the Risk of Infection
Preventative measures are the most effective way to manage the risk of port infection in immunocompromised patients. The primary action involves strict adherence to sterile technique whenever the port is accessed or the dressing is changed. This includes meticulous hand hygiene by the healthcare provider, wearing sterile gloves, and using a mask to prevent airborne contamination.
The access site must be thoroughly cleansed with an antiseptic agent, such as chlorhexidine, before a needle is inserted. Patients should ensure that medical personnel follow proper procedure:
- “Scrub the hub” vigorously with an alcohol swab before connecting any syringe or infusion line.
- Keep the transparent dressing placed over an accessed port dry and intact at all times.
- Report any sign of dressing lifting or compromise immediately.
Patients should avoid submerging the port site in water, meaning they should take showers rather than baths while the port is accessed. Regular flushing of the port with saline and an anticoagulant, typically every four to eight weeks, is necessary even when the port is not in use. This routine maintenance prevents clot formation, which can create a breeding ground for bacteria and increase the risk of infection.