Pulmonary Edema - Know More About It!

Pulmonary Edema
The term Edema refers to swelling. This swelling is generally caused by the fluids inside the blood vessels permeating to the outside of the blood vessels and into the tissues in the surrounding areas. The main causes of this happening are lack of proteins in the blood which hold the fluid in the plasma cells or because of excessive pressure in the blood vessels.

Pulmonary edema is the term used when the lungs are affected by edema. In this condition fluid accumulated in the air spaces and the lung tissues. This is also known as pulmonary congestion, lung congestion or lung water. The small blood vessels in the lungs are surrounded by air sacs known as alveoli. This is the location where oxygen is imbibed by the blood and carbon dioxide is exhaled out by the alveoli. The exchange of gases occurs in the alveoli through the thin walls, fluids are not allowed to enter into these walls unless the integrity of the walls is compromised.

When the alveoli are filled with fluid instead of air from the blood pulmonary edema occurs. This leads to problems in exchange of oxygen and carbon dioxide causing difficulty in breathing due to poor oxygenation.

Types
Generally, the most often encountered type is cardiogenic mostly left ventricular but fluid accumulation can also happen due to lung damage due to other reasons. This damage to the lungs might be caused by direct damage or due to indirect damage due to high pressure in the pulmonary circulation. When pulmonary pressure is more than the average value of 15mmHg to more than 25mmHg.

-  Cardiogenic pulmonary edema happens due to the inability of the heart to pump out the blood at a satisfactory rate which may be due to the failure of the left ventricle or fluid overload.

-  Non-cardiogenic pulmonary edema occurs when the alveoli are flooded with fluids and the capillaries are ruptured due to a negative pressure in the chest.

-  Flash pulmonary edema is rapidly starting to pulmonary edema. The most common cause is Myocardial infarction or heart attack but it can also be caused by aortic regurgitation which means blood flowing in the opposite direction because of leaking of the aortic valve in the heart. Flash pulmonary edema might occur due to any condition that causes heightened pressures in the left ventricular.

Symptoms
In this condition, the patient struggles to gain oxygen because of the excessive fluid filled in the lungs which prevent the oxygen to move into the bloodstream. The symptoms tend to worsen over time if the fluid is not removed from the lungs.

The most common sign of pulmonary edema is experiencing difficulty in breathing which might develop slowly over time or might be of a sudden onset if the patient is suffering from acute pulmonary edema. Some other common symptoms are tachypnea which is rapid breathing, easy fatigue, weakness and dizziness. Other symptoms like coughing blood which is frothy and pink, anxiety, paleness of the skin and excessive sweating can also be experienced. Hypoxia which is a low oxygen level in the blood might develop in patients with pulmonary edema. The doctor might look for abnormal sounds from the lungs like crackles on examination with a stethoscope.

The symptoms are also dependent on the type of pulmonary edema. These can be classified as:

The signs corresponding to long-term pulmonary edema include wheezing, fast weight gain particularly in the legs, difficulty breathing upon doing physical activities or when lying down, fatigue etc.

High altitude pulmonary edema exhibits symptoms such as fever, cough, rapid heart rate, headaches, and breathlessness after exertion etc.

Risk Factors
Individuals suffering from heart problems or those who have encountered the problem of heart failure at high risk for pulmonary edema. Other than this, some of the risk factors are a history of the disease in the family, blood disorders and a history of diseases affecting the lung such as chronic obstructive pulmonary disorder (COPD) and tuberculosis.

Causes

• The causes of pulmonary edema can be divided into cardiogenic and non-cardiogenic causes.
• In a healthy individual, the lungs extract oxygen from the air and release it into the bloodstream. But when fluid is filled in the lungs, this process is compromised and the body is deprived of oxygen.
• The cardiogenic causes occur due to poor functioning of the heart because of increased pressure in the blood vessels present in the lungs. The most generally encountered cause is congestive heart failure. This happens when the heart is unable to pump blood adequately throughout the individual’s body. This leads to back up the creation of pressure in the small blood vessels in the lungs and subsequently makes the fluid leak from these blood vessels. Heart attacks and abnormality in the heart valves can also lead to excessive accumulation of blood in the blood vessels in the lungs which might eventually cause pressure build-up which leads to leakage of fluid from the blood vessels into the alveoli.

Non-cardiogenic causes of pulmonary edema include:

• Acute Respiratory Distress Syndrome is a condition which leads to leakage from the alveoli because of an inflammatory response. It is caused by infections, injury to the lungs, trauma, toxin inhalation, infections of the lungs, smoking cocaine etc.
• An overdose of aspirin might cause aspirin intoxication which can lead to pulmonary edema in elderly people. An overdose of methadone or heroin can also lead to this condition.
• High altitude pulmonary edema can manifest because of rapid ascent to altitudes more than 10000 feet. Failure of kidneys and the subsequent inability to expel fluids from the body can lead to an excess build-up of fluids in the blood vessels which can cause pulmonary edema. If someone is suffering from an advanced kidney disorder, dialysis may be required to expel the fluids.
• Rapid lung expansion may sometimes cause re-expansion pulmonary edema. This can happen when a huge amount of fluid is removed from around the lungs or when the lung collapses causing lung expansion. Bleeding in the brain, surgery of the brain, brain trauma can also lead to accumulation of fluids in lungs causing neurogenic pulmonary edema.

Diagnosis

The doctor will check for fluid in the patient’s lungs or for symptoms in the lungs caused by the presence of the fluid. The doctors will perform a medical history check and physical examinations. The doctors listen to the patient’s lungs using a stethoscope, to find out if:

-  There is an increased heart rate of the patient.
-  The patient is breathing rapidly.
-  There are any crackling sounds in the patient’s lungs. 
-  There are any unusual heart sounds.

The doctors also look for a build-up of fluids in the abdomen, legs and neck for swelling. The doctors will also check if you have pale or blue coloured skin. If the doctor believes the patient has fluid in their lungs, they will take additional tests. The tests done in diagnosing pulmonary edema include:

-  Chest X-ray is done to check for fluids and any other problems persisting in the lungs of the patient.
-  Blood tests to check for oxygen levels are done. A complete blood count (CBC) of the patient may also be taken by the doctors. The doctors also check the patient’s medical history.
-  Echocardiography is a test that produces live images of the heart using sound waves. The resulting image is called an Echocardiogram. The procedure is used to check for any abnormality in the heart. The images are used to spot blood clots in the heart, fluids in the sacs around the heart and problems with the aorta which is the main nerve connected to the heart. Echocardiography is the key procedure to determine the health of the heart muscles.  
-  Electrocardiography (ECG) is a procedure which records the electrical activity of the heart over a duration using electrodes attached to the skin of the patient. Electrocardiography is done to obtain structural and functional information of the heart. It is used to judge the heart’s rhythm and find any problems related to cardiac issues. Electrocardiography is used to check for any signs of heart attack.

Treatment
Pulmonary Edema is a very serious problem which requires immediate treatment. The first line of treatment for this condition has always been Oxygen. The medical professionals deliver 100 percent of oxygen to the patient using an oxygen mask, positive pressure mark or a nasal cannula. The doctors will prescribe the right treatment and medications for the cause after diagnosing Pulmonary Edema. Depending on the condition of the patient and the cause for the problem the doctors may also suggest:

-  Preload Reducers – Preload reducers are the drugs or the medications that decrease the preload of the blood vessels. They reduce the pressure from the fluids going into the lungs and heart. Diuretics help in reduction of preload and reducing the pressure by making the patient urinate. The urine helps in eliminating the fluids from their body.

-  Afterload Reducers – Afterload reducers are the drugs that or the medications that decrease the afterload in the blood vessels. These medications dilate the patient’s blood vessels and take the pressure off the patient’s heart. Afterload is the procedure of the heart pushing out or ejection of the blood to the other body organs. Vasodilators are commonly used in the reduction of both the preload and the afterload in the blood vessels of the patient. 

-  Heart Medication – The doctors also prescribe other drugs and medications to reduce other heart problems or to prevent them from occurring in the heart of the patient. These medications control the patient’s pulse, relieve the pressure in the patient’s arteries and veins and reduce the high blood pressure of the patient. 

-  Suction Catheter – A small suction catheter might be used to extract the fluids from the lungs of the patient. This is done by attaching the catheter to a tube and inserting the tube through the air passage of the patient.

-  Morphine – Morphine is a drug that is used as a pain medication. It is found naturally in a number of plants and animals. It works directly upon the Central Nervous System (CNS) to decrease the feeling of pain in the body. The drug is used to relieve shortness of breath and anxiety. But due to the many risks involved not many doctors allow the use of morphine. The side effects include low blood pressure and reduced respiratory efforts. The drug also has a high chance of addiction and abuse. Common side effects are drowsiness, constipation and vomiting. Morphine also affects the baby if used during pregnancy or breastfeeding.

In a severe case of pulmonary edema, the patient will require critical or intensive care. Some of the patients of Pulmonary Edema may require treatments to assist their breathing. A machine is used to provide oxygen to get air into the lungs. This can also be done by a mask or a Cannula, also known as Continuous Positive Airway Pressure (CPAP). The doctors may also insert an endotracheal tube also called a breathing tube into the patient’s throat to use mechanical ventilation to help with the patient’s breathing issues.

Prevention-
There is no the way to completely prevent the disorder. People at high risk should get immediate medical attention as soon as they develop any of the symptoms. The most effective way to try and prevent pulmonary edema is to take good and proper care of your health.  Follow these tips to prevent the disorder:

-  Get vaccinated for pneumonia. 
-  Get vaccines for flu, especially if you are an older adult or if you have any issues in your heart. 
-  After having an episode of pulmonary edema, don’t stop the use of diuretics as they reduce the chances of the disorder reoccurring.

Try to decrease the chances of heart failure, which is one of the most common causes of pulmonary edema. This can be done by:
-  Visiting the doctor on a regular basis.
-  Refraining from the use of recreational drugs.
-  Avoiding smoking cigarettes.
-  Getting regular exercise and staying active. 
-  Eating healthy food and green vegetables. 
-  Maintaining a normal weight and keeping a check on excessive weight loss or weight gain.