You are called to the house of a male with difficulty breathing. While your partner cares for the patient, you review his medications. You discover Digitalis, Lasix, Lisinopril and Micro-K. Conferring with your partner, you determine the patient's complaints are symptoms of a worsening or exacerbation of congestive heart failure (CHF).
CHF occurs acutely or develops chronically and can be defined as the heart's inability to maintain adequate circulation of blood. CHF can involve the right ventricle, left ventricle or both. Signs and symptoms vary based on cause, degree of failure and ventricle involved.
Acute heart failure is most commonly caused by myocardial infarction (MI). The death of tissue results in decreased muscle contraction or valve failure. Typical signs of cardiogenic shock ensue. These include chest pain, shortness of breath and pulmonary edema.
Chronic heart failure presents more subtly than acute heart failure. It also may be more difficult to recognize. Left-ventricular failure is most concerning. Left-sided heart failure is most commonly caused by chronic hypertension. The left ventricle pushes against high arterial pressure. This causes an enlargement of the ventricular wall known as hypertrophy.
As the disease process continues, the heart will begin to remodel. Remodeling is the process of the heart muscle changing shape. Normally the heart is pointed at the bottom with the ventricles in somewhat of a 'V' shape. This shape allows the ventricle to maintain a normal ejection fraction (EF) of about 70%. This means 70% of the blood in the ventricle is pumped out. As the heart remodels, the walls of the ventricle stretch and become thinner. The shape of the ventricle becomes rounded and cardiac muscle weakens. EF will drop, and blood backs up. Left-ventricular failure results in blood backing into the pulmonary circulatory system. As pressure in the pulmonary blood vessels increases, fluid is pushed into the alveoli resulting in pulmonary edema.
The four stages of heart failure
Early stages of heart failure (Class I) present with few signs or symptoms, and activities of daily life aren't affected. Paroxysmal Nocturnal Dyspnea (PND), a condition where the patient is short of breath while lying supine, may present in early stages. PND is a result of fluid in the lungs blocking oxygen exchange. When the patient is in an upright position, the fluid is in the lung bases. When the patient lies supine, the fluid diffuses throughout the lung fields. This means more oxygen is blocked from exchanging in the alveoli. The patient will awaken with shortness of breath. The patient will progressively begin sleeping with more pillows and awake more frequently. Eventually, the patient won't be able to lay supine. Levels of B-type natriuretic peptide (BNP), a protein released to help the body compensate for CHF, will elevate and be a helpful in-hospital diagnostic tool.
Class II heart failure is still classified as mild, but the patient will begin to experience dyspnea with moderate exertion. The patient is comfortable at rest but becomes short of breath while performing routine chores.
Patients with Class III heart failure, which is considered moderate, find it difficult to carry out activities of daily life. Once-simple tasks, such as walking to the mailbox or up stairs, now come with extreme respiratory distress. Evidence of this may be seen in the patient's home. A chair at the top of the stairs may suggest the patient needs to rest frequently.
Moving on to severe heart failure, patients in Class IV heart failure are in continual distress -- even at rest. EF can approach single digits. These patients will not be able to carry out normal activities and may find themselves confined to a comfortable chair or in an upright hospital bed.
Proper assessment and treatment
Assessment of CHF patients requires a good history. Events leading to their shortness of breath help determine whether the cause is acute or chronic. They also help determine the stage of the patient's disease. Medication history, such as in the patient above, helps confirm CHF. Digitalis, an inotrope, increases force of contraction. Lasix, a diuretic, helps eliminate fluid by causing urination. The latter is commonly prescribed with such potassium supplements as Micro-K. ACE inhibitors, such as Lisinopril, decrease blood pressure and preload, which helps limit fluid backup.
Physical assessment finds these patients upright with their legs in a dependant or down position. Legs kept down decrease blood return to the heart, in turn decreasing fluid back-up into the lungs. Breath sounds will reveal bilateral rhonchi or crackles. These will usually be in the lung bases. Unilateral crackles are not indicative of CHF but suggest other diseases such as pneumonia. As the disease progresses and the bases fill with fluid, basilar sounds will become diminished or absent with crackles heard in the upper lobes. Early stages of CHF may present with wheezing. As fluid begins to move into the lungs, the bronchioles will constrict in an effort to keep fluid out. This constriction will create wheezing. This has been referred to as cardiac asthma. Caution! Treating heart failure as asthma can make the condition worse.
Continued fluid backup into the lungs will eventually cause right-ventricular failure. At this time, fluid will back up into the rest of the body. Patients will develop swollen ankles and ascites, or fluid in the abdomen. This is a sign of disease progression but not considered an acute life threat.
The goal of treatment is to oxygenate the patient and get fluid out of the lungs. High concentration of oxygen is a must. Next, consider patient position. CHF patients can be improved by helping them into an upright position as tolerated by mentation and blood pressure. Extreme cases may be treated with a bag mask assisting respiratory effort. Continuous positive airway pressure (CPAP), mask providing a continuous pressure into the lungs, may be allowed in some systems. This pressure helps the patient to exchange oxygen against the fluid backup. EMTs with pharmacologic abilities can consider higher doses of nitroglycerine such as 0.8 mg (two sprays or tablets) as an initial dose.
Your assessment was correct. The patient experienced an exacerbation of CHF confirmed by elevated BNP. The patient was evaluated to rule out pneumonia and MI. His drug doses were adjusted, and he was discharged home.