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You’ll be using new drugs and diagnostic tests
A 74-year-old female patient arrives at your emergency department (ED) complaining of fatigue and shortness of breath, with a history of myocardial infarction, hypertension, atrial fibrillation, and congestive heart failure. Her medication list includes warfarin, lanoxin, metoprolol, and enalapril. You place the patient on oxygen, attach her to a cardiac monitor, and perform pulse oximetry. The physician orders a chest X-ray, a 12-lead electrocardiogram, cardiac and metabolic lab panels, and a serum brain natriuretic peptide (BNP).
The above scenario illustrates two important new approaches given in updated guidelines for the evaluation and management of chronic heart failure, published jointly by the Bethesda, MD-based American College of Cardiology and the Dallas-based American Heart Association. They are the use of beta-blockers for heart failure and the use of BNP, a relatively new diagnostic test.
"The guidelines address a number of issues that will affect the practice of emergency nursing," according to Pat Manion, RN, MS, CCRN, CEN, trauma coordinator at Genesys Regional Medical Center in Grand Blanc, MI. "These include patient assessment, pharmacologic management, and discharge instructions." (See Orders for Patients with Heart Failure.)
Here are current approaches for heart failure addressed in the guidelines:
• Increased use of angiotensin-converting enzyme (ACE) inhibitors and beta-blockers.
For years, beta-blockers were contraindicated in patients with heart failure, Manion notes. "The rationale was that because beta-blockers have a negative inotropic effect on the heart, the resulting decrease in the force of contractions would further decrease the cardiac output and make the heart failure worse," she says. However, the body’s response to the decreased cardiac output or heart failure is tachycardia, vasoconstriction, and activation of the renin-angiotensin-aldosterone system, Manion explains.
While beneficial in the short term, these compensatory measures can lead to ventricular hypertrophy, arrhythmias, fluid retention, and cellular death, she explains. "Beta-blockers can lessen the symptoms of heart failure, improve the patient’s sense of well-being, and decrease the risk of rehospitalization and death," she says.
ACE inhibitors and beta-blockers seem to run contrary to what initial treatment should be for a typical heart failure patient, who is short of breath and hypotensive and has fluid retention, says Darlene Matsuoka, RN, BSN, CEN, CCRN, ED clinical nurse educator at Harborview Medical Center in Seattle. ACE inhibitors are antihypertensive agents, and beta-blockers decrease heart rate and stroke volume, she explains. By using the ACE inhibitors, cardiac work is lessened by decreasing the systemic vascular resistance to pump against; the beta-blockers fight the sympathetic nervous system response, says Matsuoka. "The challenge is to balance the medications given," she says.
• Use of BNP as a diagnostic test.
Brain natriuretic peptide is a biologic marker secreted by the heart in response to acute heart failure, says Manion. This lab test can be used in differentiating the dyspnea due to heart failure, from dyspnea caused by other conditions, she says.
"BNP testing is going to be used much more frequently, so ED nurses really need to know about this," stresses Sonja D. Brune, RN, MSN, CCRN, CEN, CCNS, cardiovascular clinical nurse specialist at the Central Cardiovascular Institute of San Antonio. Once you understand what the numbers mean, you can differentiate heart failure from other conditions that can mimic it, such as chronic obstructive pulmonary disease, pneumonia, and edema from other causes, she explains.
The test also helps in the patient’s prognosis, because if the BNP level is extremely high, that level correlates with a higher mortality rate, Brune notes. "Likewise, the BNP levels correlate well with the severity of disease — the higher the level, the more severe the disease," she says.
• Use of the term "heart failure."
Heart failure is a syndrome that affects the heart’s ability to fill with or to eject blood, with the primary symptoms of dyspnea, fatigue, and fluid retention, says Manion. "However, a patient may not have all three symptoms at the same time," she notes. The patient may have pulmonary congestion and edema with little dyspnea and fatigue, or dyspnea and fatigue with little evidence of fluid retention, she says. Manion points to the guidelines, which state that "both abnormalities can impair the functional capacity and quality of life of affected individuals, but they do not necessarily dominate the clinical picture at the same time." For this reason, Manion says the term "heart failure" is more accurate than "congestive heart failure."
• Emphasis on drugs to avoid.
In addition to nonsteroidal anti-inflammatory agents, the heart failure patient should avoid the following, says Manion:
• The use of nesiritide.
The use of this drug in the ED will increase dramatically, Brune predicts. "We use it without hesitation," she reports. "At first, a lot of people were nervous because it is a completely new drug, and there is a concern about hypotension." (For more information on nesiritide, see "New drug should revolutionize CHF treatment," ED Nursing, May 2002, p. 88.) However, the drug can have dramatic effect on a heart failure patient’s symptoms, she notes. Brune’s facility uses the standard dosing, which is a 2-mcg/kg bolus over one minute, followed by a 0.01-mcg/kg/min infusion for approximately 48 hours. "You get an immediate drop in the pulmonary wedge pressure within 15 minutes," she says. "The symptomatic relief occurs far quicker than the diuresis because the patient starts vasodilating."
You can use the drug for patients with renal deficiency and in the presence of arrhythmias, Brune adds. "It is not going to make either one worse," she says. If an acute myocardial infarction patient also is in heart failure, that patient will not be able to lie down because he or she is short of breath, and the drug can help in this scenario, she says. "As long as they’ve got a blood pressure that will support the use of nesiritide, they can lay down long enough for you to do the cath," says Brune.
• The use of impedance cardiography.
This diagnostic test evaluates the patient’s cardiac output and the systemic vascular resistance, and it helps you determine whether the patient’s low output state is related to hypovolemia or significant increased afterload, says Brune. The patient can have a low cardiac output for several different reasons in the presence of heart failure: They could be dehydrated and volume depleted, they could be very clamped down, or a combination of the two, she explains. You won’t necessarily see the high systemic vascular resistance on the physical exam, but it will show up on the impedance cardiography, she notes.
The thoracic fluid content can help assess for volume overload, but she cautions that a single level is not conclusive and that you must look for trends. "I think one of the biggest mistakes clinicians have made is putting too much credence on that," she says.
For more information on heart failure, contact:
• Sonja D. Brune, RN, MSN, CCRN, CEN, CCNS, Cardiovascular Clinical Nurse Specialist, Central Cardiovascular Institute of San Antonio, 927 McCullough Ave., San Antonio, TX 78215. Fax: (210) 223-9600. E-mail: sbrune@CCI-SA.com.
• Pat Manion, RN, MS, CCRN, CEN, Trauma Coordinator, Genesys Regional Medical Center, One Genesys Parkway, Grand Blanc, MI 48439. Telephone: (810) 606-7891. Fax: (810) 606-9515. E-mail: PManion@genesys.org.
• Darlene Matsuoka, RN, BSN, CEN, CCRN, Emergency Department, Harborview Medical Center, Mail Stop 359875, 325 Ninth Ave., Seattle, WA 98104. Telephone: (206) 731- 2646. Fax: (206) 731-8671. E-mail: email@example.com.
The Guidelines for the Evaluation and Management of Chronic Heart Failure in the Adult are available on the American College of Cardiology web site (www.acc.org) Click on "Clinical Statements/Guidelines," "Practice Guidelines: Evaluation and Management of Heart Failure." Single copies of the guidelines (Publication number 71-0216), which were published in the December 2001 issue of the Journal of the American College of Cardiology and the Dec. 11, 2001, issue of Circulation, are available for $5 each. To order, contact:
• American College of Cardiology, Educational Services, 9111 Old Georgetown Road, Bethesda, MD 20814-1699. Telephone: (800) 253-4636 or (301) 897-5400. E-mail: firstname.lastname@example.org.