What is ARDS?

Acute respiratory distress syndrome (ARDS)^[1] is a life-threatening form of respiratory failure. It occurs when an injury to the lungs causes its air sacs (alveoli) to fill with fluid. This fluid inhibits the lungs’ ability to fill with air and provide oxygen to the bloodstream. ARDS is commonly caused by sepsis, physical trauma, pneumonia, or the inhalation of harmful substances. While ARDS usually gets worse very quickly, it may take a few days to progress. ARDS symptoms typically begin with shortness of breath, followed by rapid breathing and wheezing. Patients with ARDS usually require support with a mechanical ventilator to supply their blood with enough oxygen. ARDS is challenging to treat, particularly when a patient has many other complicating medical problems. However, the prompt treatment of ARDS can prevent serious complications from arising, including organ damage or organ failure.

How common is ARDS?

ARDS affects approximately 200,000 patients each year^[2] in the United States. Globally, ARDS accounts for 10% of intensive care unit^[3] (ICU) admissions. ARDS can develop at any age. It typically occurs in people who have significant injuries or are critically ill. Severe shortness of breath—the main symptom of ARDS—usually develops within a few hours to a few days after the initial injury or illness. Mortality—the risk of death from developing ARDS—increases with age and the severity of the illness. Of the people who survive ARDS, some recover completely, while others experience lasting damage to their lungs.

Is ARDS the same as lung failure?

There are many types of lung failure (also known as respiratory failure^[4]). ARDS is one type of lung failure. Lung failure generally refers to any condition in which the lungs do not properly oxygenate the blood. Lung failure is a symptom rather than a diagnosis. ARDS, on the other hand, is a definitive diagnosis that involves fluids filling the alveoli. Lung failure can be acute (short-term) or chronic (ongoing). ARDS, for example, causes acute lung failure. Other conditions, such as amyotrophic lateral sclerosis (ALS)^[5], can cause chronic lung failure.

Lung failure risk factors

Respiratory failure often results from health conditions that impair your breathing. Such conditions may affect the muscles, nerves, bones, or tissues that enable breathing, and in some cases may damage or weaken the lungs themselves. Some conditions that may increase your risk^[6] for developing respiratory failure include:

• Conditions that weaken or damage the nerves and muscles that control breathing, such as amyotrophic lateral sclerosis (ALS)
• Lung diseases, such as COPD (chronic obstructive pulmonary disease), cystic fibrosis, pneumonia, and pulmonary embolism
• Acute lung injuries, such as those caused by inhaling harmful fumes
• Disorders of the spine, such as scoliosis
• Chest injuries that cause damage to the ribs or tissues that surround the lungs
• Drug or alcohol overdose—this affects the area of the brain that controls respiration, causing breath to become slow and shallow.

ARDS symptoms

The symptoms of ARDS^[7] can vary in intensity, depending on the condition’s cause and severity. The presence of underlying heart or lung disease can cause ARDS symptoms to be more severe. Some symptoms of ARDS include:

• Severe shortness of breath
• Unusually fast or shallow breathing
• A rattling sound while breathing
• Chest pain
• Rapid heartbeat
• Wet coughing
• A tingle of blueness on the fingernails, skin, or lips (cyanosis)
• Fever
• Low blood pressure (hypotension)
• Confusion
• Exhaustion or extreme tiredness

Call your provider immediately if you are having trouble breathing. If your shortness of breath is severe, call 911.

ARDS causes

The functional cause of ARDS is the leakage of fluid from the lungs’ blood vessels into their air sacs (alveoli). The presence of fluid in the alveoli limits the lungs’ normal exchange of oxygen and carbon dioxide, decreasing the concentration of oxygen in the blood. This fluid is usually kept in the blood vessels through a protective membrane. A severe illness or injury can damage this membrane, leading to the fluid leakage that causes ARDS. Such damage also causes inflammation that leads to the breakdown of surfactant—a liquid that helps keep your air sacs open. The most common causes of ARDS^[8] include:

• Sepsis^[9]: The body’s overactive and toxic response to an infection. Sepsis can lead to tissue damage, organ failure, and death.
• Physical trauma: Accidents can cause damage to the lungs or the part of the brain that controls breathing. ARDS can also be caused by the inhalation of vomit or water during a near-drowning.
• Severe pneumonia: Severe cases of pneumonia can cause damage to any or all five lobes of the lungs.
• Inhaling harmful substances: Inhaling high concentrations of smoke or toxic fumes can cause ARDS.

Most cases of ARDS occur in patients that are currently being hospitalized for another serious lung condition. Your likelihood of getting ARDS also depends on your age, health, where you live, and the setting in which you receive healthcare. Your risk of getting ARDS^[10] may increase due to infection, environmental factors, lifestyle habits, genetics, or preexisting medical conditions. Injury to your lungs also becomes more likely if you have a health condition such as fat embolism, an infected pancreas (pancreatitis), damage to the blood vessels in your lungs (pulmonary vasculitis). Some infections that increase your risk for developing ARDS include viruses, pneumonia, sepsis, and uterine infection in the mother (which can affect a newborn). Environmental factors, such as consistent exposure to air pollution, may also affect lung function. Lifestyle habits that can harm your lungs include alcohol use, drug use, and a history of smoking. Having a family history of lung problems can also put you at a higher risk for ARDS. Certain medical procedures can raise your risk for ARDS. These may include blood transfusions, lung or heart surgery, being placed on a heart-lung bypass machine, or recent chemotherapy. Some steps you can take to decrease your risk of getting ARDS^[11] include:

• Being vaccinated against conditions that may lead to lung infections, such as the flu
• Quitting smoking (or don’t start) and avoid secondhand smoke
• Limiting your alcohol consumption
• Minimizing your exposure to environmental pollution