What Is Acute Respiratory Distress Syndrome?

Get health & wellness advice into your inbox

Your privacy is important to us. Any information you provide to us via this website may be placed by us on servers. If you do not agree to these placements, please do not provide the information.

Best Milk Alternative

Acute respiratory distress syndrome (ARDS) is a severe lung condition that can cause life-threatening respiratory failure. ARDS can be caused by various factors, including trauma, infections, and inhalation injuries. Effective treatment involves providing supportive care, such as administering supplemental oxygen, utilising mechanical ventilation and prescribing medication.


Acute respiratory distress syndrome (ARDS) is a common lung condition that can cause life-threatening respiratory failure in critically ill patients. ARDS is associated with the acute onset of pulmonary oedema (when fluid builds up in the tiny air sacs (alveoli) of the lungs). Once the lungs are full of fluid, gas exchange is restricted. This can reduce the oxygen in the blood, leading to organ failure. ARDS can be caused by various factors, including trauma, infections, and inhalation injuries.1

Causes and risk factors of ARDS

What can cause ARDS?

ARDS can be caused by a wide range of factors,1 including:

  • Infections, including viral or bacterial infections and pneumonia
  • Pulmonary aspiration: when material (e.g. food and drink) from the stomach, mouth or oesophagus is accidentally inhaled into the lungs
  • Trauma, such as severe injuries to the chest or head
  • Inhalation injuries: when the airways and lungs are exposed to irritants like chemical fumes
  • Pancreatitis: inflammation of the pancreas
  • Drug overdose
  • Blood transfusions: transfusion-associated acute lung injury is usually related to fresh frozen plasma, red blood cell or platelet transfusions
  • Transplantation or surgery: including after cardiopulmonary bypass, lung resection, and lung transplants
  • Near drowning: occurs with both fresh or salt water
  • Smoke inhalation: can cause direct injury to the lungs

How does ARDS develop?

The exact cause of ARDS is not well understood. However, it is believed that after an injury to the lungs, the immune system reacts by releasing large amounts of inflammatory chemicals called cytokines.2 

These cytokines can damage the alveoli (tiny air sacs) and capillaries (tiny blood vessels) in the lungs, allowing fluid to leak in. 

Additionally, ARDS involves a loss of surfactant (fluid that stops the alveoli collapsing) and the accumulation of dead cells, debris and inflammatory fluid in the alveoli.  

A combination of these steps can lead to the following:

  • Decreased pulmonary compliance, or the ability of lungs to stretch and expand
  • Clotting in the alveolar capillaries, which causes microthrombi (tiny blood clots)
  • Impaired gas exchange, making it difficult for oxygen to pass from the alveoli to the bloodstream
  • Respiratory failure, where the oxygen supply does not meet the demand of the body due to impaired gas exchange2

If not treated, ARDS will eventually lead to organ failure due to a lack of oxygen and blood supply, resulting in death.

Risk factors for ARDS 

Aside from the aforementioned clinical causes of ARDS, several risk factors can increase the likelihood of developing ARDS,3,4 including:

  • Age: the older someone is, the higher their risk of developing ARDS
  • The extent of injury: a more severe injury is associated with a higher risk of developing ARDS
  • Chronic alcohol abuse: this is linked to a 2-3x higher risk of developing ARDS, the reason for which is unknown. However, some studies think that it may be due to a reduced antioxidant capacity in the lungs
  • History of smoking
  • Hypoalbuminemia: the loss of albumin, a protein that helps keep blood inside blood vessels
  • Obesity

Signs and symptoms of ARDS 

The symptoms of ARDS can vary depending on the patient and the severity of the condition, but common symptoms include:5

  • Severe dyspnea (shortness of breath)
  • Rapid, shallow breathing
  • Tiredness
  • Drowsiness
  • Confusion 
  • Feeling faint 

Management and treatment for ARDS

Treatment for patients can involve supportive care and medication. A physician will assess the situation and take the best course of action. The underlying cause of ARDS is usually treated to prevent further complications, using effective management options such as:6

  • Corticosteroids
  • Extracorporeal membrane oxygenation (ECMO): a machine that supplies oxygen to the blood outside the body
  • Fluid management strategy: patients may undergo a conservative (which involves receiving diuretics, sometimes in combination with an albumin solution or restricted fluid intake) or liberal fluid strategy (which involves receiving a lot of fluid and sometimes, diuretics) 
  • Inhaled vasodilators: these help blood vessels expand
  • Lung protective ventilation to keep lung volume and pressure balanced

Diagnosis of ARDS 

Diagnosis of ARDS is based on the patient's medical history, a physical examination and imaging tests such as an echocardiogram (an ultrasound of your heart and nearby blood vessels), X-rays or computed tomography (CT) scans. 

Since ARDS affects the lungs and their ability to sufficiently provide oxygen to the body, pulse oximetry or a blood test may be used to check blood oxygen levels. A blood test may also test for infection.5

Prevention of ARDS 

People can prevent ARDS by addressing underlying risk factors such as obesity, alcohol and tobacco use, and avoiding lung injury by staying safe around chemicals and smoke, for example. Additional steps include treating lung infections promptly.5

If you notice a decline in blood oxygen levels, e.g. while using a home pulse oximeter, you should consult healthcare services immediately. Thisis a medical emergency due to the risk of vital organs like the heart and brain being starved of oxygen.5

Complications of ARDS 

ARDS can cause potentially severe complications, including:

  • Muscle weakness: patients that recover may experience nerve and muscle damage, which cause pain and weakness5
  • Respiratory failure: when the body's demand for oxygen exceeds the respiratory system's oxygen supply, respiratory failure occurs1,2
  • Organ failure: low oxygen levels in the bloodstream means organs will receive less oxygenated blood, which may result in their failure1,2
  • PTSD and depression: patients may develop psychological conditions due to the traumatic experience of being critically ill with ARDS5
  • Pulmonary hypertension (high blood pressure): ARDS can cause fluid to build up in the lungs, increasing blood pressure in the pulmonary artery, which takes blood from the lungs to the heart7


Can ARDS be cured? 

There is no specific cure for ARDS, but patients can expect to fully recover and regain lung function with appropriate treatment and management.6

Is ARDS contagious? 

ARDS itself is not contagious,6 although some contagious diseases like the flu can cause ARDS.5

Can smoking cause ARDS? 

Tobacco use can increase the risk of developing lung infections and cause injury to the lungs that may ultimately trigger ARDS, but it is not a direct cause of the condition.4

What can I expect if I have ARDS? 

If you have ARDS, you may experience various symptoms, such as shortness of breath, confusion, fatigue, and drowsiness, as your lungs will not be working at full efficiency. 

In hospital, patients can expect supportive care, such as mechanical ventilation and oxygen therapy, to help their lungs regain function and increase blood oxygen levels. 

Your treatment will depend on the underlying cause of ARDS. For example, you may be prescribed antibiotics if you have a bacterial infection. 

If the severity of ARDS is high, you may be hospitalised in the intensive care unit (ICU) to ensure ongoing monitoring and prompt treatment. 

Recovery can take weeks to months, with patients also reporting long-term complications.5

How common is ARDS? 

ARDS is a relatively rare condition, but it is very serious if it occurs. About 1 in 3 people who get it will die. However, death generally occurs due to the underlying cause rather than ARDS itself.5

When should I see a doctor?

If you experience a combination of symptoms associated with ARDS, including shortness of breath, low blood oxygen, shallow breathing or fatigue, you should immediately seek medical attention. With ARDS, it is essential to treat any underlying conditions, as prompt diagnosis and treatment can improve the chances of recovery.5


ARDS is a severe lung condition that can cause life-threatening respiratory failure. ARDS is caused by various factors, including smoke inhalation, trauma, and infection. Symptoms include shortness of breath, shallow breathing, confusion and tiredness. 

Some people have risk factors for developing ARDS, such as old age or obesity. However, it is unclear whether the high mortality rate is caused by ARDS rather than underlying medical conditions.1

Effective treatment for ARDS involves providing supportive care, such as oxygen therapy, mechanical ventilation and medication. The underlying cause of ARDS should be targeted during treatment and considered when taking preventative measures. 

Preventative measures include prompt treatment of lung infections and avoiding smoking. By detecting and treating the condition early, patients can improve their chances of survival and reduce their risk of long-term complications.1


  1. Matthay MA, Zemans RL, Zimmerman GA, Arabi YM, Beitler JR, Mercat A, et al. Acute respiratory distress syndrome. Nat Rev Dis Primers. 2019 Mar 14;5(1):18.
  2. Saguil A, Fargo MV. Acute respiratory distress syndrome: diagnosis and management. Am Fam Physician. 2020 Jun 15;101(12):730–8.
  3. Hudson LD, Milberg JA, Anardi D, Maunder RJ. Clinical risks for development of the acute respiratory distress syndrome. Am J Respir Crit Care Med. 1995 Feb;151(2 Pt 1):293–301.
  4. Odeyemi Y, Moraes AGD, Gajic O. What factors predispose patients to acute respiratory distress syndrome? Evidence-Based Practice of Critical Care [Internet]. 2020 [cited 2023 Apr 1];103-108.e1. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7152288/ 
  5. Acute respiratory distress syndrome (ARDS) [Internet]. NHS. 2017 [cited 2023 Apr 1]. Available from: https://www.nhs.uk/conditions/acute-respiratory-distress-syndrome/
  6. Griffiths MJD, McAuley DF, Perkins GD, Barrett N, Blackwood B, Boyle A, et al. Guidelines on the management of acute respiratory distress syndrome. BMJ Open Respiratory Research [Internet]. 2019 May 1 [cited 2023 Apr 1];6(1):e000420. Available from: https://bmjopenrespres.bmj.com/content/6/1/e000420 
  7. Moloney ED, Evans TW. Pathophysiology and pharmacological treatment of pulmonary hypertension in acute respiratory distress syndrome. European Respiratory Journal [Internet]. 2003 Apr 1 [cited 2023 Apr 1];21(4):720–7. Available from: https://erj.ersjournals.com/content/21/4/720 

Get health & wellness advice into your inbox

Your privacy is important to us. Any information you provide to us via this website may be placed by us on servers. If you do not agree to these placements, please do not provide the information.

Best Milk Alternative
[optin-monster-inline slug="yw0fgpzdy6fjeb0bbekx"]
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

Get our health newsletter

Get daily health and wellness advice from our medical team.
Your privacy is important to us. Any information you provide to this website may be placed by us on our servers. If you do not agree do not provide the information.

Leave a Reply

Your email address will not be published. Required fields are marked *

my.klarity.health presents all health information in line with our terms and conditions. It is essential to understand that the medical information available on our platform is not intended to substitute the relationship between a patient and their physician or doctor, as well as any medical guidance they offer. Always consult with a healthcare professional before making any decisions based on the information found on our website.
Klarity is a citizen-centric health data management platform that enables citizens to securely access, control and share their own health data. Klarity Health Library aims to provide clear and evidence-based health and wellness related informative articles. 
Klarity / Managed Self Ltd
Alum House
5 Alum Chine Road
Westbourne Bournemouth BH4 8DT
VAT Number: 362 5758 74
Company Number: 10696687

Phone Number:

 +44 20 3239 9818