An overview of Pulmonary Edema

Pulmonary edema is when fluid collects in the air sacs of the lungs, making it difficult to breathe. It can result from heart disease, pneumonia, and other health issues.

Pulmonary edema can be acute (occurring suddenly) or chronic (occurring more slowly over time). Acute pulmonary edema is a medical emergency and requires immediate medical attention.

Pulmonary edema can be broadly classified into cardiogenic and noncardiogenic pulmonary edema.

Cardiogenic or volume-overload pulmonary edema arises due to a rapid elevation in the hydrostatic pressure of the pulmonary capillaries. This is typically seen in disorders involving left ventricular systolic and diastolic function (acute myocarditis including other etiologies of non-ischemic cardiomyopathy, acute myocardial infarction), valvular function (aortic/mitral regurgitation and stenosis in the moderate to the severe range), rhythm (atrial fibrillation with a rapid ventricular response, ventricular tachycardia, high degree, and third-degree heart block)

Noncardiogenic pulmonary edema is caused by lung injury with a resultant increase in pulmonary vascular permeability leading to the movement of fluid, rich in proteins, to the alveolar and interstitial compartments. Acute lung injury with severe hypoxemia is referred to as acute respiratory distress syndrome (ARDS) and is seen in various conditions directly affecting the lungs, such as pneumonia, inhalational injury, or indirectly, such as sepsis, acute pancreatitis, severe trauma with shock, multiple blood transfusions.

During normal breathing, the small air sacs in the lungs, known as alveoli, fill up with air. The lungs take in oxygen and expel carbon dioxide. Pulmonary edema occursTrusted Source when fluid floods the alveoli.

This flooding causes two problems:

The bloodstream cannot get enough oxygen.

The body cannot expel carbon dioxide properly.

Common causes of pulmonary edema include:

pneumonia

sepsis (blood infection)

exposure to certain chemicals

organ failure that causes fluid accumulation, such as congestive heart failure,kidney failure, or liver cirrhosis

near-drowning

inflammation

trauma

reaction to certain medications

overdose of certain drugs, including opioids

Pulmonary edema also occur as part of a condition called acute respiratory distress syndrome (ARDS), a severe inflammation of the lungs that leads to significant breathing difficulties. Direct injury to the lungs or inflammation in other parts of the body can cause this condition.

Other possible causes include:

brain injuries such as brain bleeding, stroke, head injury, brain surgery,tumor, or seizure

high altitude

blood transfusion

The following heart-related problems can also lead to pulmonary edema:

Fluid overload:This can result from kidney failure or intravenous fluid therapy.

Hypertensive emergency:This is a severe increase in blood pressure that places excessive strain on the heart.

Pericardial effusion with tamponade:This is a buildup of fluid around the sac that covers the heart, which can decrease the heart’s ability to pump.

Severe arrhythmia:This can be tachycardia (fast heartbeat) or bradycardia (slow heartbeat), both of which can result in poor heart function.

Severe heart attack:This can damage the muscle of the heart, making pumping difficult.

Abnormal heart valve: This 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 and are often the result of ARDS.

Acute pulmonary edema causes significant breathing difficulties and can appear without warning. It is an emergency and requires immediate medical attention. Without proper treatment and support, it can be fatal.

In addition to breathing difficulties, the following symptoms can indicate acute pulmonary edema:

cough, often with a pink, frothy sputum

excessive sweating

anxiety and restlessness

feelings of suffocation

pale skin

wheezing

rapid or irregular heart rhythm (palpitations)

chest pain

If the pulmonary edema is chronic, symptoms are usually less severe until the body’s system can no longer compensate. Symptoms may include:

difficulty breathing when lying flat (orthopnea)

swelling (edema) of feet or legs

rapid weight gain due to the accumulation of excess fluid

paroxysmal nocturnal dyspnea, or episodes of severe sudden breathlessness at night

fatigue

increased breathlessness with physical activity

People with an increased risk of developing pulmonary edema should follow a doctor’s advice to manage the condition.

If a person has congestive heart failure, following a healthy, balanced diet and maintaining a moderate body weight can help ease symptoms and reduce the risk of future episodes of pulmonary edema.

Regular exercise also improves heart health, as do other lifestyle habits, including:

Reducing salt intake:Excess salt can lead to water retention, which requires the heart to work harder.

Lowering cholesterol levels:High cholesterol can lead to fatty deposits in the arteries, which can increase the risk of heart attack and stroke in addition to pulmonary edema.

Smoking cessation:Tobacco increases the risk of a number of health conditions, including heart disease, lung disease, and circulatory problems.

It is possible to minimize altitude-induced pulmonary edema by making a gradual ascent,taking medications before traveling, and avoiding excess exertion while progressing to higher altitudes.

A person will undergo a physical exam first. A doctor will use a stethoscope to listen to the lungs for crackles and rapid breathing and to the heart for abnormal rhythms.

The doctor will order blood tests to determine blood oxygen levels. They will often order additional blood tests to check the following:

electrolyte levels

kidney function

liver function

blood counts and blood markers of heart failure

An echocardiogram or an electrocardiogram (EKG) can help determine the condition of the heart.

The doctor may order a chest X-ray or a lung ultrasound to see whether there is any fluid in or around the lungs and to check the size of the heart. They may also order a CT scan.

To raise a person’s blood oxygen levels, a healthcare professional will administer oxygen through either a face mask or nasal cannulas, which are tiny plastic tubes that a healthcare professional places in a person’s nose to provide oxygen.

Healthcare professionals may place a breathing tube in the trachea if a ventilator — a machine that helps a person breathe — is necessary.

If tests show that the pulmonary edema is the result of a problem in the circulatory system, healthcare professionals will administer intravenous medications to help reduce fluid volume and regulate blood pressure.

Diuretics are the most commonly usedTrusted Source medication and can help reduce fluid buildup by increasing the production of urine.

Depending on the specific cause and a person’s symptoms, a healthcare professional may use any of the following other medications to treat pulmonary edema:

Vasodilators: These medications dilate the blood vessels to decrease pulmonary congestion.

Calcium channel blockers: These help reduce high blood pressure.

Inotropes: This type of medication can increase the force of heart muscle contractions so that the heart can pump blood throughout the body.

Morphine:This medication can help reduce anxiety and shortness of breath. However, because of its potential risks, healthcare professionals do not often recommend it.

Three Stages of Pulmonary Edema

Vascular Redistribution

Seen in pulmonary venous hypertension – chronicelevation of LA pressure

Increased caliber of the upper lobe vessels compared tothe lower lobe vessels.

Vessels in the upper lobes are usually smaller than thelower lobe vessels

Artery:Bronchus ratio = 0.85

At the hilum the ratio should be equal

In the lower lobes, the arteries are larger with a ratio of 1.35

Interstitial Edema

Caused by increased fluid within the pulmonary veins.

Fluid leaks into the interlobular and peribronchial interstitium

Increased interstitial markings

Indistinctness of the pulmonary vasculature

Peribronchial cuffing Fluid leakage into the

peribronchovascular interstitium

Kerley A, B and C lines all represent thickened interlobular septa

Kerley B: peripheral lung, perpendicular to pleura

Kerley A: radiate from hila

Kerley C: overlapping of A and B lines

Alveolar Edema

Alveoli fill with fluid as the continued fluidaccumulation cannot be compensated by lymphaticdrainage

Perihilar opacifications are present

Can see pleural effusions and cardiomegaly

Usually symmetric and dependent

Complications of pulmonary edema depend on the cause.

In general, if pulmonary edema continues, the pressure in the pulmonary artery can rise (pulmonary hypertension). Eventually, the heart becomes weak and begins to fail, and pressures in the heart and lungs go up.

Pulmonary edema complications may include:

Breathing difficulty

Swelling of the legs, feet and belly area

Buildup of fluid in the membranes that surround the lungs (pleural effusion)

Congestion and swelling of the liver

Immediate treatment is necessary for acute pulmonary edema to prevent death.