Infused therapies used to treat pulmonary arterial hypertension (PAH)
The first medications used to treat pulmonary hypertension were continuously infused prostacyclins. Flolan was the first infused PH therapy approved by the FDA and we now have several options including IV or SQ Remodulin, and Veletri.
Continuous IV treatments for pulmonary hypertension
The continuous IV infusions used to treat pulmonary arterial hypertension are Flolan, Remodulin, and Veletri. A small pump called a Cadd Legacy is commonly used to infuse these medications. This small pump weighs about 3 lbs. The pump is carried on the patient at all times. Many patients use the standard carrying case issued with the pump for every day use but other patients have created their own systems for carrying their pumps. The medication is mixed into a plastic container called a cassette that is attached to the pump and thin plastic tubing runs from the pump to the patient’s central line. These medications run 24 hours a day, 7 days a week, 52 weeks a year. They must never be interrupted except to change the cassette.
There are several types of tunneled central lines used to infuse prostacyclins but the same basic principles apply to whichever type of central line is used. It is called a tunneled line because the line is inserted into the chest then tunneled under the skin, over the clavicle, and then into a large vein. The line itself is a small plastic catheter that sits with its end just outside of the heart. The line is placed in an operating room by a surgeon with the patient under anesthesia.
Sutures are initially placed to hold the line in place. After 4-8 weeks, tissue around the cuffs of the catheter has grown in and the sutures can be removed at the pulmonary hypertension clinic. Because the line is direct access to the heart it is very important to keep the line and area around the line clean. A sterile dressing will be applied where the line enters the body and should be changed every 7 days or more frequently if it becomes wet or compromised. The specialty pharmacy teaches patients how to perform dressing changes during the education of how to use the prostacyclin medications. The dressing and central line site should always be covered by special waterproof dressing while showering and swimming is never allowed.
The central line dressing and insertion site should be inspected everyday. The pulmonary hypertension team should be notified immediately if there is any redness, swelling, drainage, or pain around the site. The pulmonary hypertension team should also be notified of any fevers. Because the tip of the central line sits in the blood stream outside of the heart, an infection is considered an emergency and can be life threatening.
Continuous subcutaneous infusions
Remodulin is currently the only drug that offers a continuous subcutaneous administration option. A small pump about the size of a cell phone is used in this option. A small cartridge is filled with Remodulin and inserted into the pump. Thin plastic tubing runs from the pump to a small plastic cannula that the patient has placed in their subcutaneous tissue. SQ Remodulin is infused similarly to how patients on an insulin pump infuse their insulin. There is nothing permanently inserted into the patient. If the site falls out or becomes compromised a new site is started. The catheter is most commonly placed in the tissue on the abdomen but the upper legs, buttocks, and back of the arms can also be used.
The subcutaneous catheter is very small and not painful itself, but the Remodulin can cause irritation and pain to the area. The subcutaneous site is changed out every three weeks or so. Each pulmonary hypertension center will have their own protocol for how often this has to happen. Like the IV dressing the SQ dressing should be covered by special waterproof dressing and should not get wet. The site should be inspected every day. Redness and some swelling are normal for a SQ Remodulin site but the patient should call right away if they notice any drainage from the area or develop a fever. Since the SQ catheter does not go into a blood vessel an infection of the site is not life threatening but still a serious problem that needs to be addressed by the pulmonary hypertension specialist.