Pulmonary edema, a medical emergency, is an accumulation of fluid in the lungs. Most often a consequence of congestive heart failure, pulmonary edema typically occurs when the heart is unable to pump blood out through the arteries as quickly as it is returned to the heart through the veins. Failure of the left side of the heart (left ventricle) causes blood to accumulate in the veins of the lungs (pulmonary veins), producing a dangerous rise in blood pressure within these veins. Sustained high pressure in the pulmonary veins eventually forces some fluid from the blood into the surrounding microscopic air sacs (alveoli), which transfer oxygen to the bloodstream. As the alveoli fill with fluid, they can no longer provide adequate amounts of oxygen to the body. Symptoms, especially severe breathing difficulty, develop over the course of a few hours and may be life-threatening. Although the outlook for pulmonary edema is favorable if the underlying disorder is treated in a timely fashion, the overall outcome for the patient depends upon the nature of the underlying disorder. Adults at high risk for heart failure are most commonly affected.
A less common form of the disease, high-altitude pulmonary edema (which may occur while mountain-climbing, for instance), is also life-threatening if not treated quickly. Strenuous activity upon arrival at high altitudes may cause a dangerous rise in the pressure in the pulmonary veins, forcing fluid out of the veins into the alveoli. After people become acclimated to the altitude, strenuous activity does not pose such a risk. High-altitude pulmonary edema most often affects young adults under age 25 who are unacclimatized to the altitude but otherwise in good health. Symptoms appear within 24 to 72 hours and necessitate immediate descent to a lower altitude for treatment. (Air travelers are generally not at risk for this disorder because commercial airplane cabins are pressurized.)
What Causes Pulmonary Edema?
- Congestive heart failure due to high blood pressure, aortic or mitral valve disease, or cardiomyopathy is a common cause of pulmonary edema.
- A heart attack may cause pulmonary edema.
- A variety of other conditions, such as lung infections, extensive burns, liver or kidney disease, Hodgkin’s disease, pneumothorax or nutritional deficiencies, may lead to pulmonary edema in some cases.
- Overdoses of heroin, morphine and other narcotics may lead to pulmonary edema.
- Rapid ascent to high altitudes followed immediately by heavy exertion may cause high-altitude pulmonary edema.
Signs and Symptoms of Pulmonary Edema
- Severe breathing difficulty, including wheezing; rapid, shallow breathing; and a feeling of suffocation
- Cough, dry at first, but later producing pink, frothy sputum
- Fatigue
- Profuse perspiration
- Blue tinge to the nails, lips, or skin
- Palpitations
- Anxiety and restlessness
- Loss of consciousness
- Sudden respiratory distress after sleep
- Wheezing or gurgling sounds when breathing
Prevention
- To prevent heart disease, don’t smoke; eat a low-fat, low-cholesterol diet; exercise regularly; and lose weight if you are overweight.
- Have your blood pressure and cholesterol checked.
- Allow a few days to adjust to a higher altitude before engaging in strenuous physical activity. If you have an existing heart condition, your doctor may alter your medication prior to a high-altitude trip.
Diagnosis of Pulmonary Edema
- Patient history and examination of the chest is necessary.
- Blood samples are taken to measure oxygen and carbon dioxide content.
- A chest x-ray may be taken.
- Arterial blood gas (ABG) analysis may be performed to identify metabolic acidosis.
- An electrocardiogram (ECG) may be performed to identify a heart rhythm disturbance or evidence of a heart attack.
- Pulmonary artery catheterization may be performed to identify left ventricular failure.
- An ultrasound test (echocardiogram) may be performed to evaluate the pumping function and thickness of the heart, and to evaluate the mitral and aortic valves.
- A stress test or angiogram (injection of a contrasting dye into the blood vessels to make them clearly visible on x-rays) may be performed to check for the presence of coronary artery disease or narrowed arteries.
How to Treat Pulmonary Edema
- Call an ambulance or go to the nearest emergency room immediately. While waiting for an ambulance, sit upright. If possible, sit facing backward on an armless chair, with your raised arms resting on the chair back, to ease breathing.
- Pure oxygen is administered through a face mask or nasal tube or by an assisted positive pressure ventilator, which mechanically aids breathing.
- Morphine is given to relieve anxiety and to decrease the blood flow through the lungs.
- Diuretics, such as furosemide, bumetanide, or ethacrynic acid, are administered to promote excretion of excess fluids.
- Sodium nitroprusside or digoxin may be prescribed to dilate the arteries and strengthen the contractions of the heart muscle.
- Inhaled bronchodilating drugs, such as aminophylline, may be administered to relax constricted bronchial passages.
- It is imperative to return to a lower altitude immediately to obtain emergency medical care for high-altitude pulmonary edema. If possible, ask a ranger to call a helicopter if someone becomes too disabled to walk.
When to Call a Doctor
- EMERGENCY Call an ambulance immediately if you develop symptoms of pulmonary edema.
- EMERGENCY Descend immediately to a lower altitude and call for emergency medical treatment if you develop high-altitude pulmonary edema.
Source:
Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference
Simeon Margolis, M.D., Ph.D., Medical Editor
Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50
Updated by Remedy Health Media
