Pulmonary edema occurs when fluid accumulates in the air sacs of the lungs – the alveoli – making it difficult to breathe. This interferes with gas exchange and can cause respiratory failure.
Pulmonary edema can be acute (sudden onset) or chronic (occurring more slowly over time). If it is acute, it is classed as a medical emergency needing immediate attention.
The most common cause of pulmonary edema is congestive heart failure, where the heart cannot keep up with the demands of the body.
Treatment of pulmonary edema usually focuses on improving respiratory function and dealing with the source of the problem. It generally includes providing additional oxygen and medications to treat the underlying conditions.
Fast facts on pulmonary edema
Pulmonary edema is a condition involving fluid buildup in the lungs.
Sudden onset (acute) pulmonary edema is a medical emergency.
Symptoms include shortness of breath, cough, decreased exercise tolerance or chest pain.
Pulmonary edema can be acute or chronic.
To raise the patient’s blood oxygen levels, oxygen is given either through a face mask or prongs – tiny plastic tubes in the nose. A breathing tube may be placed into the trachea if a ventilator, or breathing machine, is necessary.
If tests show that the pulmonary edema is because of a problem in the circulatory system, the patient will be treated with intravenous medications to help remove fluid volume and control blood pressure.
During normal breathing, the small air sacs in the lungs – alveoli – fill up with air. Oxygen is taken in, and carbon dioxide is expelled. Pulmonary edema occurs when the alveoli are flooded.
When the alveoli are flooded, two problems occur:
The bloodstream cannot get enough oxygen.
The body is unable to get rid of carbon dioxide properly.
Common causes include:
sepsis (blood infection)
exposure to some chemicals
organ failure that causes fluid accumulation – congestive heart failure, kidney failure, or liver cirrhosis
reaction to certain medications
Besides direct injury to the lungs, as in ARDS, other causes include:
brain injuries such as brain bleeding, stroke, head injury, brain surgery, tumor, or seizure
Cardiogenic pulmonary edema
Pulmonary edema that is due to a direct problem with the heart is called cardiogenic.
Congestive heart failure is a common cause of cardiogenic pulmonary edema; in this condition, the left ventricle cannot pump out enough blood to meet the needs of the body.
This causes a buildup of pressure in other parts of the circulatory system, forcing fluid into the air sacs of the lungs and other parts of the body.
Other heart-related problems that can lead to pulmonary edema include:
Fluid overload – this can result from kidney failure or intravenous fluid therapy.
Hypertensive emergency – a severe increase in blood pressure that puts excessive strain on the heart.
Pericardial effusion with tamponade – a buildup of fluid around the sac that covers the heart. This can decrease the heart’s ability to pump.
Severe arrhythmias – this can be tachycardia (fast heartbeat) or bradycardia (slow heartbeat). Either can result in poor heart function.
Severe heart attack – this can damage the muscle of the heart, making pumping difficult.
Abnormal heart valve – can affect the flow of blood out of the heart.
Causes of pulmonary edema that are not due to poor heart function are called noncardiogenic; they are typically caused by ARDS (acute respiratory distress syndrome). This is a severe inflammation of the lungs that leads to pulmonary edema and significant breathing difficulties.