Cardiogenic Acute Pulmonary Edema – Causes, Symptoms, Diagnosis And Treatment

Cardiogenic Acute Pulmonary Edema – Causes, Symptoms, Diagnosis And Treatment

Acute pulmonary edema is a pathological condition defined by the presence of large amounts of fluid in pulmonary alveoli and in pulmonary interstitium. Cardiogenic acute pulmonary edema is an acute form of heart failure caused by increased pressure in the pulmonary capillary.

Acute Pulmonary Edema

Causes:

The mechanisms of production of acute pulmonary edema are:

1. Increased pressure in pulmonary capillary
2. Cardiogenic acute pulmonary edema by decreasing blood evacuation from the left atrium: atrial fibrillation, acute mitral regurgitation, mitral stenosis, thrombus or myxoma in the left atrium.
3. Cardiogenic acute pulmonary edema caused by left ventricular diastolic dysfunction: aortic stenosis, hypertension, hypertrophic cardiomyopathy, acute myocardial ischemia.
4. Cardiogenic acute pulmonary edema caused by left ventricular systolic dysfunction: acute myocardial ischemia, myocarditis, dilated cardiomyopathy, heart failure.
5. Non-cardiogenic acute pulmonary edema: parenteral hyperhydration.
6. Decreased oncotic pressure: nephrotic syndrome, cirrhosis.
7. Increased capillary permeability (acute respiratory distress syndrome): pneumonia, aspiration syndrome, inhalation of toxic gases, disseminated intravascular coagulation, anaphylaxis shock, acute pancreatitis.
8. Altered lymphatic drainage: pulmonary carcinomatosis
9. Incompletely understood causes: altitude acute pulmonary edema, neurogenic acute pulmonary edema, eclamsie, post anesthesia and post cardio-conversion.

Acute Pulmonary Edema Mechanism

Cardiogenic acute pulmonary edema is caused due to the increase pulmonary capillary pressure from 8-12 mm Hg (normal) to over 18 mm Hg.

Symptoms:

The main symptoms of acute pulmonary edema are the shortness of breath, cough, marked anxiety, cold and increased sweating and symptoms of the background heart disease.

Dyspnea is very intense, may occur in a patient who had until then no charge of this symptom (for example, a acute pulmonary edema that occurs after the onset of a myocardial infarction), or can overlap with the symptoms of preexisting heart failure . Dyspnea become worse when the patient is lying down.

Coughing can sometimes be the main charge of the patient. Cough may be dry or may be accompanied by the elimination of airy, pink sputum.

Physical examination revealed the following:

1. A patient that is restless, anxious or confused with sweaty, pale or mottled skin, with central type cyanosis, the patient is breathing typically standing at the edge of the bed and using accessory respiratory muscles.
2. Marked dyspnea, possibly vesicular murmur and prolonged expiration, rales crackles, of which level increases from the bases of the lungs to tops and can include the entire lung field.
3. Tachycardia, hypertension or hypotension and, depending on the case, rhythm disturbances or different heart murmurs.
4. In some cases, may appear signs of right heart failure: hepatomegaly, jugular turgor, hepato-jugular reflux, lower limb edema.

Acute Pulmonary Edema Symptoms

Paraclinical investigations:

Chest radiography shows pulmonary hilum, which are increased in volume and with wiped contours, that have the appearance of “butterfly wings” and in case of chronic heart failure, will appear cardiomegaly and pleural liquid. Radiological changes do not occur at the onset of a acute pulmonary edema.

Oximetry indicates hypoxia and hypocapnia. In severe forms may be present hypercapnia and respiratory acidosis, which constitute signs of gravity.

Other useful tests are:

• Electrocardiogram can detect: various arrhythmias, left ventricular hypertrophy or letf atrial hypertrophy, myocardial ischemia or myocardial infarction;
• Echocardiography can detect the presence of valvulopathies, of thrombus or myxoma in the left atrium, impaired function of the left ventricle.

Positive diagnosis of cardiogenic acute pulmonary edema is relatively simple, it is based on patient history and symptoms.

Acute Pulmonary Edema Ragiography

Evolution and prognosis:

Evolution of cardiogenic acute pulmonary edema is unpredictable. In a patient treated properly and quickly, acut pulmonary edema can be remitted. Sometimes, however, death occurs.

Treatment:

Treatment of acute pulmonary edema requires the following measures:

1. General measures: keep the patient in a sitting position, administration of oxygen on mask or nasal tube, dyspnea sedation with morphine.
2. Furosemide, administrated intravenous in dose of 80-120 mg or more, divided into four doses of 40 mg, each, is the primary mean of treatment of cardiogenic acute pulmonary edema. Its beneficial effects are explained by the occurrence of venous dilation, which will lead to decreased preload (quickly installed) and diuresis (which occurs in 20-90 minutes after the administration of furosemide).
3. Nitroglycerin, vasodilator with rapid effect, administrated sublingual (0.5 mg tablets, the dose can be repeated in 5-10 minutes) or intravenously, in the conditions of systolic blood pressure higher than 100 mm Hg.
4. Administration of digoxin can bring benefits by improving the cardiac tonus or by decreasing the heart rate in case of atrial fibrillation. Digoxin administration is contraindicated in cardiogenic acute pulmonary edema associated with mitral stenosis or with acute myocardial infarction.
5. Other therapeutic measures in cardiogenic acute pulmonary edema are: miofilin administration or the administration of angiotensin converting enzyme inhibitors, assisted ventilation, circulatory support with counterpulsation balloon and the treatment of the cause that led to the installation of cardiogenic acute pulmonary edema.