New drug should revolutionize CHF treatment

When a 65-year-old man came to the ED in severe respiratory distress from congestive heart failure (CHF), his initial respiratory rate was 30. He was unable to talk and used accessory muscles for respiration. "He had frothy sputum and was about to go into respiratory arrest," says Robert Takla, MD, FACEP, medical director of emergency services at St. John NorthEast Community Hospital in Detroit.

"I was ready to intubate him, but had wanted to try Natrecor [Scios Inc., Sunnyvale, CA], as I recently read a journal article on it,"1 Takla says, referring to the drug that, in generic form, is named nesiritide. "So I obtained an initial arterial blood gas."

On a 100% fraction of inspired oxygen, the patient’s arterial blood gas was pH 7.034, partial pressure of carbon dioxide was 62, partial pressure of oxygen was 99, and oxygen saturation was 93%. Takla treated the patient with lasix and nesiritide, and the clinical response was dramatic.

Only 75 minutes later, a repeat arterial blood gas was pH 7.36, partial pressure of carbon dioxide was 39, partial pressure of oxygen was 215, and oxygen saturation was 97%. The patient was talking comfortably. "In fact, he asked me if he could go home, and just a few minutes earlier, I was expecting to put him on life support," says Takla.

Drug is cutting edge

Nesiritide is a recombinant form of human B-type natriuretic peptide, a naturally occurring protein in the body secreted by the ventricles in response to congestive heart failure, but not in sufficient quantity to be therapeutically effective, says Takla. "Now it is synthesized and given to patients, and I have had tremendous success with it," he says. "It is cutting edge and should revolutionize the treatment of CHF."

Its mechanism of action and indication differs from traditional CHF drugs such as diuretics, nitroglycerin, and inotropic agents, which are historically used in the treatment of refractory or severe CHF, says Takla. Natrecor is used instead of nitroglycerine or nitroprusside, he adds. The drug is recommended for patients who present in Class II, III, or IV acute CHF, he says. It is the only drug in a new class of medications to be approved for treatment of CHF in the last decade, adds Takla. "It should be on everyone’s CHF guideline or pathway," he urges. (See IV Nesiritide [Natrecor] Policy/Procedure.)

Nesiritide is a natriuretic peptide and is one of a new category of medications, according to June Howland Gradman, RN, MS, MBA clinical director of cardiac services at University of Chicago Hospital. "There are a number of clinical trials going on for other agents that work by similar mechanisms," she reports. "This is a new arena in the treatment of heart failure."

Here are some things to consider about nesiritide:

• Watch for improvement of symptoms. You should see marked improvement in the shortness of breath and dyspnea symptoms that brought the patient to the ED, says Gradman.

Expect to see patients placed on this medication improve in a very short period of time, says Takla. "Improvement is seen as quickly as 10 or 15 minutes of receiving the bolus," he says. The dose is a bolus of 2 mcg/kg followed by an infusion of 0.01 mcg/kg per minute, he says. "Patients do not need any invasive monitoring such as a swan or arterial line," says Takla. "In fact, they can be admitted or observed in a telemetry setting and do not need to be in the [intensive care unit]."

• Monitor urine output.

You should monitor the patient’s urine output, Gradman says. "The drug encourages salt and water excretion along with vasodilation," she says. "Expect to see a good urine output, which is a clue that the drug is working."

Takla adds that the medication is synergistic with diuretics because it works in a different area of the kidneys, so the urine output response is very good. "This is especially helpful in renal insufficient patients," he says.

• Watch for side effects. In clinical trials, hypotension has occurred in 2% to 4% of patients, says Gradman. "If they don’t have the ability to function and don’t respond to it, you’ll see a drop in pressure," she says. If this occurs, stop the infusion and support blood pressure, says Gradman.

• Evaluate the patient’s baseline functional status. Be familiar with the following four functional classes for congestive heart failure, stresses Gradman:

— Class I: patients with documented heart disease of any type who are completely symptom-free;

— Class II: slight limitation of physical activity because symptoms (shortness of breath, chest pain) occur only with more than ordinary physical activity;

— Class III: marked limitation of physical activity because symptoms occur even with ordinary physical activity (e.g., eating meals);

— Class IV: severe limitation of physical activity because symptoms occur even at rest (e.g., in a sitting or lying position).

Knowing these functional classes for heart failure is a way to evaluate how the patient is doing, says Gradman. "Patients likely to seek treatment come into the ED in functional Class III or IV," she notes. A patient coming into the ED in functional Class III will have marked limitations in his or her physical activity, and Class IV will be symptomatic at rest, Gradman says. "Drug therapy can move them to a Class I or II with minimal symptoms."

Gradman notes that point-of-care testing for brain natriuretic peptide levels is now available in the ED. "These levels are being used to evaluate patients coming to the ED with shortness of breath," she says. "A high level can indicate heart failure and consideration of Natrecor for treatment."

Reference

1. Colucci WS, Elkayam U, Horton DP, et al. Intravenous nesiritide, a natriuretic peptide, in the treatment of decompensated congestive heart failure. N Engl J Med 2000; 343:246-253.

Sources and resource

For more information about the management of CHF using nesiritide, contact:

• June Howland Gradman, RN, MS, MBA, Clinical Director of Cardiac Services, University of Chicago Hospital, 5841 S. Maryland Ave., MC 5022, Chicago, IL 60637. Telephone: (773) 702-1894. Fax: (773) 702-4198. E-mail: jgradman@uchospitals.edu.

• Robert Takla, MD, FACEP, Emergency Services, St. John NorthEast Community Hospital, 4777 E. Outer Drive, Detroit, MI 48234-3281. Telephone: (248) 642-9893. Fax: (248) 642-5075. E-mail: rtakla@comcast.net.

For more information about Natrecor, contact: Scios Inc., 820 W. Maude Ave., Sunnyvale, CA 94085. Telephone: (866) 262-6466 or (408) 616-8200. Fax: (408) 616-8206. Web: www.natrecor.com.