Pulmonary Arterial Hypertension
High-risk Help
Complex therapy requires careful consideration

By Cathy Severson, RN, BSN
August 10, 2004

In 1997, the fen-phen phenomenon hit the public media with as much fanfare as the latest celebrity legal battle. Physicians linked the fat-fighting combination therapy of phentermine and fenfluramine or dexfenfluramine to valvular regurgitation in about 30% of patients taking the drugs. Manufacturers withdrew fenfluramine and dexfenfluramine from the market after a request from the U.S. Food and Drug Administration. Although many patients were asymptomatic, some were left with a sad legacy from their battle with obesity — pulmonary artery hypertension.

PAH is characterized by progressive increases in pulmonary artery pressure, leading to right ventricular failure and death. (See “The pressure of pulmonary arterial hypertension” sidebar.) The disease can frustrate health care providers, but treatment options do exist. Epoprostenol sodium infusion therapy can reduce the incidence of mortality from PAH.1 It is FDA-approved for patients with symptomatic, primary PAH (defined by the World Health Organization as Class III and IV) or PAH associated with scleroderma.

But epoprostenol is a long-term, complex, and expensive treatment. Nurses must understand this therapy to help patients derive the most benefit
from it.

Decision time

Determining eligibility for epoprostenol goes beyond assessing for clinical indications. (See “Epoprostenol sodium” sidebar.) Because the drug’s half-life is only minutes, patients must receive a continuous infusion via a central line and an infusion pump. Thus, the patient’s mental and physical capacity for the complicated therapy must be evaluated. The nurse should interview both the patient and a significant other who will offer help and support. (See “Is Your Patient Ready for Epoprostenol Therapy?”)

Providers also should consider whether their facility’s resources are sufficient for the comprehensive and intensive management these patients require. Although epoprostenol therapy can be lifesaving when used appropriately, it also can complicate and sometimes worsen symptoms with catastrophic results — rebound pulmonary hypertension or death — if initiated, administered, or managed incorrectly. If sufficient resources are not available, patients should be referred to a specialized PAH clinic.

Before making the final decision to proceed with epoprostenol therapy, patients should see the delivery system, observe all procedures, and, ideally, meet another patient undergoing therapy. These steps can dramatically reduce anxiety associated with starting long-term IV therapy. The Pulmonary Hypertension Association [www.phassociation.org] can help locate patients and provide support and information.

Patients must have realistic perceptions about the drug. On the plus side, epoprostenol can improve the quality of and even extend the patient’s life. The downside: It’s not a cure, and it can have adverse effects. What’s more, it’s impossible to predict the magnitude or duration of the therapeutic response. Patients should understand that initial improvement in symptoms does not guarantee continued improvement or preclude eventual decline.

Start-up

The approach to education and drug initiation differs among large centers, depending on experience and resources, but some common practices exist. Experienced health care providers — ideally, the ones who will follow the patients long term — should teach them. At Mayo Clinic, patients receive preprinted, step-by-step directions in a manual that covers pump operation, drug reconstitution, and cassette and tubing change. Teaching should occur in intensive blocks over a period of days and close to the initiation of the drug.

Whether the epoprostenol infusion is started in an inpatient or outpatient setting, the nurse must observe the patient closely, check vital signs, and have immediate access to emergency equipment and care. The starting infusion rate is typically 2 to 3 ng/kg/min, delivered via a CADD Legacy pump. Vital signs are obtained before and at least every half-hour for two to three hours after drug initiation.

The patient and support person(s) should demonstrate their proficiency in all phases of epoprostenol administration. Because of the potentially fatal complications, including death, associated with interruption of the infusion, patients should remain at or near the PAH center until they have demonstrated full competence in delivery system maintenance. Patients should be given two pumps as a safeguard against pump malfunction or failure.

The catheter of choice for long-term epoprostenol therapy is a 6.6 or 9 French single lumen tunneled central venous catheter using an internal jugular vein approach (see Figure 1). The catheter should be tunneled to an exit site low enough so the patient can see the site to care for it independently. Sutures at the site should be removed after two to four weeks.

Each patient is instructed to see his or her local physician within the first month of returning home so the physician can become familiar with the patient’s status, assist with assessment, and monitor treatment, including anticoagulation.

Ongoing treatment

Maintenance for epoprostenol therapy includes regular communication, dose modification, and prevention/management of complications.

Communication. Ask patients to call their health care provider at least every two weeks and obtain the following information:
> Verification of current pump rate
> Number and type of vials being mixed
> Current weight
> Interim change in symptoms (including functional status) or adverse effects, plus relationship to dose changes
> Verification of prothrombin time monitoring, including recent INR
> Status of catheter site
> Any new symptoms or deterioration, which should prompt a clinic visit for evaluation.

Hemodynamic assessment is usually performed after one year of therapy, providing the patient had initial symptomatic improvement and continued with stable symptoms and exercise capacity (as measured by the six-minute walk test). Right heart catheterization is the gold standard for pulmonary hemodynamic assessment. The results of a one-year catheterization should be used to guide future dosing regimens and help make decisions about remaining on the transplant waiting list. The expectation at one year should be improvement in pulmonary hemodynamics, but by no means normalization.

Dosage adjustment. Epoprostenol dosing should be individualized for the patient, with consideration for severity of symptoms, adverse effects, and underlying disease. In general, the dose is gradually increased at regular intervals or depending on symptoms. Many patients who experience improvement in symptoms during initiation of epoprostenol will report increased symptoms after returning home to a more physically challenging environment. Thus, it’s important to have regular contact.

Complications. Prevention of emergencies is always the first line of defense. All potential emergency situations and proper responses should be discussed and “role-played” with patients during initial teaching. The greatest emergency is interruption of the infusion, usually due to pump malfunctions or accidental dislodgement of the catheter. If anything happens to the central venous catheter, the infusion must be continued via a peripheral IV until central access can be reestablished. Encourage patients to wear a medic alert bracelet or carry a laminated card listing their health problems, as well as warnings not to stop the infusion pump.

Infections related to long-term indwelling central lines can be minimized by strict attention to aseptic care. Although some patients have had a central venous catheter for 10 years without infection, others have experienced multiple infections in less than a year. Local site infections should be treated aggressively. The catheter should be removed if site infection recurs despite two courses of antibiotics and immediately if blood cultures are positive.

Epoprostenol therapy can be demanding for both patient and nurse. But through careful planning and follow-up, patients can enjoy significant benefits, and nurses can feel confident that they have done all they can to make sure that patients obtain the best results possible.

Cathy Severson, RN, BSN, is a supervisor at the Pulmonary Hypertension Clinic at Mayo Clinic in Rochester, Minn.

References

1. McLaughlin VV, Shillingon A, Rich S. Survival in primary pulmonary hypertension: the impact of epoprostenol therapy. Circ. 2002;106(12):1477-1482.

2. Rubin LJ, Mendoza J, Hood M, et al. Treatment of primary pulmonary hypertension with continuous intravenous prostacyclin (epoprostenol): results of a randomized trial. Ann Int Med. 1990;112(7):485-491.

3. Barst RJ, Rubin LJ, Long WA, et al. A comparison of continuous intravenous epoprostenol (prostacyclin) with conventional therapy for primary pulmonary hypertension. N Engl J Med. 1996;334(5):296-301.

4. Wax D, Garofano R, Barst RJ. Effects of long-term infusion of prostacyclin on exercise performance in patients with primary pulmonary hypertension. Chest. 1999;116(4):914-920.

5. Rich S, Kaufmann E, Levy PS. The effect of high doses of calcium-channel blockers on survival in primary pulmonary hypertension. N Engl J Med. 1992;327(2):76-81.

6. Rich S, McLaughlin VV. The effects of chronic prostacyclin therapy on cardiac output and symptoms in primary pulmonary hypertension. J Amer Cardiol. 1999;34(4):1184-1187.