Several different types of subcutaneous (under the skin) ports are available. The subcutaneous port differs from the external catheter in that it is completely under the skin. A small metal chamber (one and a half inches in diameter) with a rubber top is implanted under the skin of the chest. A catheter threads from the metal chamber (portal) under the skin to a large vein near the collarbone, then inside the vein to the right atrium of the heart (see Figures 8-2 and 8-3). Whenever the catheter is needed for a blood draw or infusion of drugs or fluid, a needle is inserted by a nurse through the skin and into the rubber top of the portal.
How it's put in
The subcutaneous port is implanted under general anesthesia in the operating room in a procedure that generally takes less than an hour. Sometimes local anesthesia is used for older children or teens. The surgeon makes two small incisions: one in the chest where the portal will be placed, and the other near the collarbone where the catheter will enter a vein in the lower part of the neck. First, one end of the catheter is placed in the large blood vessel of the neck and threaded into the right atrium of the heart. The other end of the catheter is tunneled under the skin where it is attached to the portal. Fluid is injected into the portal to ensure that the device works properly. The portal is then placed under the skin in the right chest, and stitched to the underlying muscle. Both incisions are then stitched closed. The only evidence that a catheter has been implanted are two small scars and a bump under the skin where the portal rests.
Figure 8-2. Parts of the subcutanoeus port
Figure 8-3. Subcutaneous port
Before my child's surgery to have a port implanted, I saw other children being wheeled into the operating room screaming and trying to climb off the gurney to return to the parents. It broke my heart. When it was Jennifer's turn, I asked them to give her enough premedication so that she was relaxed and happy to go. I also insisted that I be in the recovery room when she awoke.
Christine had her port surgery late at night. The resident gave her some premedication, then the chief resident ordered him to give her more. She felt so silly that she looked at me, giggled, and said "Mommy has a nose as long as an elephant's." I asked the surgeon if I could be in the recovery room before she awoke, and he said, "Sure." When I told the nurse that I had permission to go in recovery, she refused. When I persisted, she became angry. I told her that my child was expecting to wake up seeing my face, and I wanted to be there. I suggested that she should go in and ask the surgeon to resolve the impasse. When she came out, she let me in the recovery room.
Because the entire subcutaneous port is under the skin, the device must be accessed in order to be used. To access the catheter, the skin is thoroughly cleansed with antiseptic, then a special needle is inserted through the skin and the rubber top of the portal. The needle is attached to a short length of tubing that hangs down the front of the chest. EMLA cream (see Chapter 3, Coping with Procedures) can be applied one hour before the needle poke to anesthetize the skin, or ethyl chloride can be sprayed on right before the poke. Subcutaneous ports have a rubber top (septum) that is self-sealing after needle removal and are designed to withstand years of needle insertions. Use of a special (non-coring) needle is essential, because it allows the rubber septum to self-seal when it is removed. Failure to use this type of needle will result in leakage of fluid into the tissues.
If the child is in a part of treatment that requires the line to be used every day, the nurse will attach the tubing to IV fluids or will close the end off with a sterile cap after flushing with saline solution. A transparent dressing will be put over the site where the needle enters the port. The port can remain accessed in this way for up to seven days. After that time, to avoid the risk of infection, the needle should be removed and the port reaccessed when necessary. If the needle and tubing are to be left in place, it is important to tape them securely to the chest to avoid accidents.
At the end of delayed intensification while getting Cytoxan, Meagan (3 years old) got a line infection. Because she hated tape removal, we did not secure the IV tubing to her stomach or chest. On one of her many trips to the potty, we accidentally tugged on the tubing and caused a very small tear in the skin around the needle. It became infected. We did home antibiotics on the pump and felt very fortunate that we were able to clear the line with antibiotics. We were glad our doctor was not too quick to remove the line, but it did require two weeks off chemotherapy.
If the port is only needed infrequently, e.g., during the maintenance phase, this will be the sequence of events: clean the site, put in the needle, rinse the line with saline, give the drug or draw blood, rinse the line with saline, add heparin to the line, withdraw the needle, and place an adhesive bandage over the site.
The entire port and catheter are under the skin and therefore require no daily care. The skin over the port can be washed just like the rest of the body. Frequent visual inspections are needed to check for swelling, redness, or drainage.
The subcutaneous port must be accessed and flushed with saline and heparin at least once every 30 days, which usually coincides with the monthly clinic visit and blood checks. This procedure is done by a nurse or technician. The port system requires no maintenance by the parent or patient.
My son had a Port-a-cath for three years, from ages 14 to 17. During that time, he played basketball, football, softball, and threw the shot in track. His port was placed on his left side just below his armpit. For football, I worked with the trainer, and we developed a special pad that went into a "custom" pocket I sewed into some T-shirts. That way the port had a little extra padding. We also found shoulder pads that had a side piece that covered the area. He never had any problems or soreness from the port.
The risks for a subcutaneous port are similar to those for the external catheter: infection, clots, and rarely kinks or rupture. If the needle is not properly inserted through the rubber septum or if the wrong kind of needle is used, fluids can leak into the tissue around the portal.
Brent (8 years old) has had a Port-a-cath for 33 months with absolutely no problems. He uses EMLA to anesthetize it prior to accessing. He hates finger pokes so much that he has his port accessed every time he needs blood drawn.
We had a few unusual problems in the beginning with the catheter. It was a bit kinked where the catheter went under the clavicle (collarbone) and would not easily draw. This caused more stress than anything in the hospital, because their middle-of-the-night blood draws were always an ordeal for our daughter. They needed to wake her up and try multiple manipulations. Once we were familiar with its idiosyncrasies and were outpatient, we worked it out much better. Then about halfway through maintenance, her catheter broke at the kink and traveled into her heart. To make a long story short, it was retrieved by a cardiologist without major surgery, and she got a new one placed, this time with the catheter going down from her neck. It works like a dream.
Most studies show that the infection rate of subcutaneous ports is lower than that of external catheters. If the subcutaneous port does become infected, it is treated the same as an external catheter port is treated.
Katy had two infections in her Port-a-cath during the 27 months of her leukemia treatment. One occurred during reinduction when the tape loosened during a blood transfusion. She developed a fever the next day and required fourteen days of vancomycin. Eighteen months later, we went in for her monthly vincristine, and she became ill in the car on the way home. Her skin became white and clammy, and she felt faint and nauseated. She spiked a 102° temperature which only lasted for two hours. The blood culture both times grew staphylococcus epi.
Kinks, clots, ruptures
These events rarely occur with the subcutaneous port. If they do occur, they are treated as described in the external catheter section.
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