What Is Acute Respiratory Distress Syndrome?
Acute Respiratory Distress Syndrome (ARDS) is a severe, life-threatening condition that occurs when the lungs are severely injured, often by injury or infection.
ARDS begins when fluid from the smallest blood vessels in the lungs starts to leak into the alveoli — the tiny air sacs where oxygen exchange takes place. Normally, a protective membrane (called the alveolar epithelium) keeps this fluid in the vessels. Severe illness or injury can cause damage to the membrane, however, leading to fluid leakage.
Once this happens, the lungs then become smaller and stiffer, making breathing more difficult. The amount of oxygen in the blood then falls — known as hypoxemia — and the body becomes starved for oxygen. This lack of oxygen harms the brain and other tissues and eventually leads to organ failure.
Causes
There are numerous direct and indirect causes of ARDS:
The most common cause of ARDS is sepsis, a serious and widespread infection of the bloodstream.
Breathing high concentrations of smoke or chemical fumes can trigger the condition, as can inhaling (aspirating) vomit or experiencing a near-drowning episode.
Serious cases of pneumonia can affect all sections of the lungs and trigger ARDS.
Severe trauma, such as burns, falls, or car crashes, can directly damage your lungs or the portion of the brain that controls breathing.
Pancreatitis (inflammation of the pancreas), drug overdoses, and multiple blood transfusions can lead to the release of inflammatory molecules and proteins into the bloodstream, which then damage the linings of the lungs.
Risks
Most people suffering from ARDS are already in the hospital due to another injury or illness. Many are critically ill.
While it’s unclear who will develop the condition, certain factors can increase the risk, including:
Advanced age
A history of tobacco use
Alcoholism
Presence of chronic lung disease
High-risk surgery
Symptoms
While the symptoms of ARDS can vary in intensity, they often develop rapidly due to significant lung inflammation and fluid accumulation.
The primary symptom is severe shortness of breath, which can develop within days or mere hours of the underlying injury or illness. This is often accompanied by rapid, shallow, or even labored breathing.
Low blood oxygen levels, or hypoxemia, is another common symptom. This symptom can lead to confusion, lethargy, and/or cyanosis, a bluish discoloration of the skin and mucous membranes due to inadequate oxygenation. In severe cases, it can lead to decreased consciousness or even a coma.
ARDS patients can experience low blood pressure, as well as symptoms related to the underlying cause of ARDS, such as fever and signs of infection in sepsis or chest pain in trauma.
Treatment
There is no known cure for ARDS. The rapid progression and severity of symptoms necessitate immediate intensive care, as the condition can quickly lead to respiratory failure. Treatment focuses on supporting the patient while the lungs heal.
While all patients with ARDS require extra oxygen, high levels of oxygen can also injure the lungs. A ventilator is used to open airspaces that have shut down, help the patient breathe, and make sure he or she is getting the right amount of oxygen while the underlying cause of the ARDS can be addressed.
When oxygen and ventilator therapies are at high levels and blood oxygen is still low, patients are sometimes positioned on their stomachs to get more oxygen into the blood. This technique is called proning and can temporarily help improve oxygen levels in the blood. ARDS patients often need sedation to relieve shortness of breath, relieve agitation, and adjust to the ventilator. They may also be prescribed diuretics to help increase urination, remove excess fluid from the body, and prevent fluid from building up in the lungs.
A small percentage of patients are candidates for a complicated and potentially risky treatment called extracorporeal membrane oxygenation (ECMO), which involves sending blood outside of the body and pumping it through a membrane that adds oxygen, removes carbon dioxide, and then returns the blood to the body.
Recovery
Despite the serious nature of ARDS, most patients survive the condition.
Patients with ARDS may require ventilation for long periods of time — typically seven to 14 days. Doctors may also suggest a tube be placed directly into the windpipe through the neck (tracheostomy) by a surgeon. This tube can easily be removed once the patient no longer needs a ventilator.
While it can also take weeks for ARDS patients to recover from ventilator support, they will not require oxygen on a long-term basis and will regain most of their lung function. Some may struggle with muscle weakness and may require an additional hospital stay or pulmonary rehabilitation to regain their strength.
If you or someone you know is experiencing shortness of breath or has suffered an injury affecting the lungs, seek emergency care immediately. If you think you are at risk for ARDS, please call 423-710-3864 to make an appointment. You may also click here to use our quick and easy online scheduling system. We will help you quickly diagnose your issues so we can start you on an effective treatment plan.
Sources: Mayo Clinic, National Institutes of Health, American Lung Association
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