Learn About ARDS
Acute respiratory distress syndrome (ARDS) is a rapidly progressive disease occurring in critically ill patients. The main problem in ARDS is that fluid leaks into the lung making breathing difficult or impossible.
- ARDS occurs rapidly and leads to respiratory failure
- Most patients with ARDS will be on a ventilator (life support)
- The main problem in ARDS is that fluid leaks into the lung making it difficult for our lungs to get oxygen into the blood
What Is ARDS?
ARDS occurs when there is another insult or injury to the body. This could any number of injuries such as pneumonia, breathing stomach contents into the lung, trauma, inflammation of the pancreas, any serious infection in the body, smoke inhalation from a house fire, medication reactions, near drowning or even blood transfusions. These insults to the body result in an inflammatory reaction that releases numerous natural molecules into the bloodstream. Normally this inflammatory reaction will be protective and help us fight infection or heal from an injury. However, in some people these inflammatory molecules will lead to the smallest blood vessels in the lungs to leak fluid. Fluid leaves these small vessels and goes into the tiny air sacs in our lungs called alveoli. These tiny air sacs fill with this fluid preventing oxygen from getting into the blood stream.
How ARDS Affects Your Body
The fluid that leaks into the lung makes it very difficult for the person to breath and leads to low oxygen in the blood. This is called hypoxemia. Initially this can be overcome by providing oxygen to the patient. The fluid in the lungs makes the lung very stiff and difficult to inflate. This increases the work that we perform to breath and get air into our lungs. This increased work of breathing and low oxygen level is what is known as respiratory failure. In order to improve the amount of oxygen and reduce the work of breathing most, if not all, ARDS patients will be placed on a ventilator to support them while the lung heals. If the inflammation and fluid in the lung persists some patients will go on to develop scarring in the lungs. This is known as the fibrotic stage of ARDS. It is during this stage that the lung can “pop” and deflate leading to a collapsed lung. This is known as a pneumothorax.
How Serious Is ARDS?
It is estimated that there are about 200,000 cases of ARDS each year in the United States. ARDS is a very serious disease and unfortunately even with the best medical care the chances of dying from this disease are around 30 to 50%. Those surviving the disease will often have long hospital stays. One of the biggest problems with this disease is that many patients will develop complications while they are in the intensive care unit. Some of these complications include pneumonia, collapsed lungs, other infections, severe muscle weakness, confusion, and kidney failure.
ARDS Symptoms, Causes & Risk Factors
ARDS may initially be diagnosed as pneumonia or pulmonary edema (fluid in the lungs due to heart disease). However, the doctor will begin to suspect ARDS if the patient is not getting better and has one of the known causes of ARDS.
What Are Symptoms of ARDS?
All patients with ARDS will have shortness of breath, which is usually very severe. They will also have cough, and many will have fever. Those with ARDS will also have fast heart rates and be breathing rapidly. Occasionally they will experience chest pain especially with inhaling. Some patients that have very low oxygen levels may have bluish coloring of nails and lips from the severely decreased oxygen levels in the blood.
What Causes ARDS?
The causes of ARDS are divided into 2 categories: direct injuries to the lung or indirect injuries to the lung. Some of the direct injuries to the lung include pneumonia, breathing stomach contents into the lung, near drowning, lung bruising from trauma (such as a car accident), and smoke inhalation from a house fire.
The indirect injuries to the lung include inflammation of the pancreas, severe infection (also known as sepsis), blood transfusions, burns and medication reactions.
Fortunately, most patients with the above problems will not develop ARDS. It is not known why some will. In those that do develop ARDS the inflammatory reaction designed to help us heal becomes out of control. This leads to fluid leaking from the smallest blood vessels into the lung.
What Are Risk Factors?
While it is not clear who will develop ARDS, there are a few factors that may increase the risk for ARDS. These factors include:
- A history of cigarette smoking
- Oxygen use for a pre-existing lung condition
- Recent high-risk surgery
- Low protein in the blood
- Alcohol abuse
- Recent chemotherapy
When to See Your Doctor
Most patients that develop ARDS will already be in the hospital but some may no be. The doctor should be called if the patient is experiencing shortness of breath above baseline levels. Also the doctor should be called, if there is new cough or fever.
Diagnosing and Treating ARDS
How Is ARDS Diagnosed?
The diagnosis is based on the patient’s symptoms, vital signs and chest x-ray when there are known risk factors present such as pneumonia or trauma. There is no single test that will confirm the diagnosis of ARDS. Patients with ARDS will have rapid onset of shortness of breath and very low oxygen in the blood. They will always require high amounts of oxygen. The chest x-ray will show fluid present in both lungs that is described as infiltrates by doctors interpreting chest x-rays. It is important that there be no evidence of heart disease which can also cause fluid to accumulate in the lungs. ARDS will often worsen in the first few days following the diagnosis before the lung begins to heal.
How Is ARDS Treated?
Because there is no direct cure for ARDS the treatment is focused on supporting the patient while the lung heals. The goals of this supportive care are to keep enough oxygen in the blood to prevent further damage to the body and to treat whatever caused ARDS in the first place. This must be done safely without leading to other problems for the patient. Another important part of the care for ARDS patients is to prevent and manage complications related to being in an ICU.
All patient with ARDS will require oxygen therapy. Even 100% oxygen is usually not enough and the patient will need to be placed on a ventilator. A ventilator is a machine that will deliver breaths through a tube inserted into the trachea or windpipe. While the ventilator is needed to support the patient the settings must be carefully chosen to avoid causing more injury to the lung. It is now known that the size of the breath (tidal volume) set on the ventilator is very important and needs to be kept at low levels to avoid damaging the lungs even more. Low tidal volumes have been shown to improve the survival from ARDS. The amount of oxygen given to the patient through the ventilator is set to the lowest possible level.
Hospitalized patients are typically in bed on their backs. However we now know that placing the patient face down can help improve oxygen levels in the blood and increase survival in patients with ARDS. This is a very complicated task that takes an entire team to accomplish, and some patients maybe too sick for this treatment. There are specialized beds designed to help position patients in the ICU face down and although they are convenient they are not absolutely necessary for this therapy.
Sedation and medications to prevent movement
It is uncomfortable and painful to be on the ventilator. This often leads to restlessness and patient agitation, which can lead to high pressures in the lung or even cause oxygen levels to drop even further. In order to keep patients comfortable and prevent this patients often require sedation to keep them calm. While the goal is to have the patient be interactive this is not often possible in ARDS patients and they will require deep sedation. There are medications called paralytics that can temporarily prevent patients from moving. One research study suggested that using these medications might improve the outcomes of ARDS. Because of side effects related to these medications are significant this treatment is not always necessary.
While ARDS is a problem of fluid leaking into the lungs and not too much fluid in the body, most doctors will try to keep ARDS patients on the dry side. This is done by given medication called diuretics to cause increased urine output. This must be done carefully because too much fluid removal can lead to low blood pressure or kidney problems.
ECMO stands for extracorporeal membrane oxygenation. This is a very complicated treatment that takes blood outside of the body and pumps it through a membrane that adds oxygen and removed carbon dioxide and then returns the blood to the body. This is a high-risk therapy with many complications that is not for every patient.
Much of the current research in this disease is focused on preventing ARDS in patients that are at risk. The cholesterol lowering mediations known as statins did not help ARDS. A recent study showed us that giving aspirin to hospitalized patients at risk for ARDS did not decrease the development of ARDS. Future studies aimed at preventing ARDS will be starting in the near future.
Recovering from ARDS
What to Expect
ARDS is a serious disease that is frightening for both patients and families to endure. The outcomes tend to be better in younger patients, trauma patients and when the ARDS is due to blood transfusions. Surprisingly most patients will not die from severe low oxygen levels in the blood. However, the chance of dying increases dramatically if other organs begin to fail. This could include liver failure, kidney failure or severely decreased blood pressure.
Managing the Disease
Often patients will require the ventilator for longer periods of time. Although there is no set time, after about 7 to 14 days the doctors may need to place a tracheostomy. A tracheostomy is a tube that is surgically placed directly into the windpipe through the neck. This would only be placed if doctors felt it would take longer than two weeks to remove the patient from the ventilator. This tube is not permanent and can easily be removed once the patient no longer needs the ventilator. It is important to note that even in those with the most severe lung damage the lung can heal, and even the sickest patient’s can recover lung function if they survive the initial illness. Most patients will not require oxygen on a long-term basis and the lung function tests will be normal or only minimally impaired. Those that survive ARDS often have prolonged hospitalization due to severe weakness that can develop during critical illness. Although the weakness improves with time and physical therapy, some weakness has been found to persist for as long as one year. Most patients find the weakness to be more of a problem than any breathing issue.
Facing ARDS may cause fear, anxiety, depression, and stress for both patients and their loved ones. Joining a support group may help you adjust to your condition. You can see how other people who have the same symptoms have coped with them. Talk to your doctor about local support groups, or check with an area medical center.
Support from family and friends also can help relieve stress and anxiety. Let your loved ones know how you feel and what they can do to help you.
The Lung Association recommends patients and caregivers join our Living with Lung Disease Support Community to connect with others facing this disease. You can also call the Lung Association’s Lung Helpline at 1-800-LUNGUSA to talk to a trained respiratory professional who can help answer your questions and connect you with support.
Learn more about ARDS at:
Questions to Ask Your Doctor about ARDS
Because most people who develop ARDS already are hospitalized, it falls upon their caregivers to advocate for them and consult with their medical team. If you have a loved one with ARDS, ask their doctors the following questions:
- What is the difference between acute lung injury and ARDS?
- What is the prognosis for survival and discharge from the hospital in ARDS? Just how sick is my family member with ARDS?
- My family member requires significant sedation (and perhaps paralysis) to facilitate ventilation…what are risks of this?
- If my family member has an acute episode of ARDS and is able to be discharged from the hospital, how long until they reach maximum recovery?
- What are chances my family member will be able to recover to their previous level of lifestyle activity?
- What do the healthcare workers caring for my family member mean by FIO2 and PEEP?
- If someone requires mechanical ventilation, how long does it take to be weaned?
- What are the main risks/side effects of mechanical ventilation?
- Should my family member be taking antibiotics and/or steroids?
Nathaniel Marchetti, DO, FCCP
Date Last Reviewed