In some pregnancies affected by hemolytic disease of the fetus and newborn (HDFN), a catheter known as a permacath may be placed to provide easy access to the bloodstream.
This is often in cases of very high or aggressive antibody titers or if there is a history of HDFN in previous pregnancies. It is more convenient and reduces the discomfort of having needles inserted repeatedly.
What is HDFN?
Hemolytic disease of the fetus and newborn (HDFN) is an immune-mediated red blood cell (RBC) disorder that occurs when a baby’s RBCs break down quickly, which is called hemolysis. HDFN is caused by a mismatch between a mother’s and her baby’s blood type (A, B, AB, or O) or Rhesus (RhRh factor A protein or antigen found on red blood cells. When an Rh-negative mother carries an Rh-positive fetus, her immune system may make antibodies that attack the fetus' red blood cells.) factor (Rh-positiveRh-Positive A blood type trait that means your red blood cells have the Rh(D) antigen. or Rh-negativeRh-Negative A blood type trait that means your red blood cells lack the Rh(D) antigen.) during pregnancy. Numerous antibodiesAntibody A protein made by the immune system that recognizes and attacks foreign substances, such as bacteria, or in HDFN, fetal red blood cells carrying incompatible antigens. to RBC antigensAntibody A protein made by the immune system that recognizes and attacks foreign substances, such as bacteria, or in HDFN, fetal red blood cells carrying incompatible antigens. can be linked to HDFN, such as those from the ABO and Rh blood groupBlood group A classification of blood based on inherited markers found on red blood cells. The ABO and Rh blood groups are most common in HDFN. systems.
In severe cases of HDFN, early intervention during pregnancy can help delay the onset of fetal anemiaAnemia A condition that occurs when the body doesn’t have enough healthy red blood cells to carry oxygen to its tissues. In HDFN, anemia occurs when maternal antibodies destroy fetal red blood cells. and help push back more invasive procedures, such as intrauterine transfusions (IUTIntrauterine transfusion A procedure that delivers donor red blood cells to the fetus through the umbilical vein to treat severe anemia caused by HDFN.) until it is safer for the fetus.
What is a permacath?
A permacath is an intravenous (IV) line that is inserted into a blood vessel, often in the neck or upper chest, under the collarbone. It gives easy access to the bloodstream for frequent treatments such as dialysis, chemotherapy, or in the case of HDFN-affected pregnancies, plasmapheresis and IVIGIntravenous immunoglobulin A therapy made from donated antibodies that may help reduce the mother’s immune response and protect the fetus.. Following delivery of the baby or when it is no longer needed, the permacath can be removed in a simple procedure.
Having a permacath inserted
Permacath placement is a surgical procedure that takes around 45 minutes, under general anesthetic or local anesthesia. Your healthcare team will advise you on how to prepare for the placement. You may need to fast for approximately 4 hours and avoid certain medications the day before.
An incision will be made in your neck or on your chest and the catheter will be inserted with the help of a guidewire, and possibly ultrasoundUltrasound An imaging test that uses sound waves to monitor fetal growth, development and signs of complications during pregnancy. or x-ray. The tip of the catheter will be inserted into the right atrium of your heart. Stitches will hold it in place. At the exit site of the catheter a clear dressing will be applied. The two ports at the end of the catheter will remain uncovered.
This common procedure should not be painful, with pressure on the insertion site the only discomfort.
Living with your permacath
Immediately after the procedure and for the next few days, you may notice some bruising and discomfort around the insertion site. It is important to monitor the incision for any signs of infection.
To avoid complications such as infection, blood clots or moving the catheter, it is important to take proper care of your permacath. You will receive clear advice on how to keep it clean. This involves keeping the dressing dry and flushing the catheter regularly.
