Acute respiratory distress syndrome
Acute respiratory distress syndrome (ARDS) is a life-threatening condition where the lungs are unable to work properly. It is caused by injury to the capillary wall either from illness or a physical injury such as major trauma. This results in the wall becoming leaky, leading to a build-up of fluid and the eventual collapse of the air sacs, leaving the lungs unable to exchange oxygen and carbon dioxide.
Acute respiratory failure (ARF) is a term often used alongside ARDS, but it is a broader term that refers to the failure of the lungs from any causes, such as chronic obstructive pulmonary disease (COPD).
ARDS is unlikely to occur on its own and is usually the result of another health condition or serious accident or injury. People who experience ARDS are therefore likely to have already been admitted to hospital. Signs that a person could have developed ARDS include breathlessness or blue fingers or lips.
There are two types of events that can cause ARDS; direct injury to the lungs and indirect injury to other parts of the body.
- Contents of the stomach moving into the lung (known as gastric aspiration)
- Near drowning
- Severe trauma to the lungs
- Smoke and toxic gas inhalation
- A fat embolism – when fat from the body moves into the respiratory system and causes problems
- Widespread swelling in the body, caused by an overreaction of the immune system (known as severe sepsis)
- Multiple blood transfusions
- Inflammation in the pancreas (known as pancreatitis)
- Blood clotting
- Drug overdose
Doctors identify ARDS based on a number of criteria, including worsening lung symptoms, a chest x-ray showing fluid in the lungs, lung failure without a known cause or the syndrome occuring within a week of a known injury.
The condition is treated in a number of ways:
- Mechanical ventilation, which helps the lungs breathe artificially after they have stopped working
- Fluid management, either restricting fluid or supplying extra fluid depending on the patient’s needs
- Strategies which use the airways to access the injured lung could prove beneficial but there has been little research into the success of these treatments
- Techniques and devices that involve taking blood from a patient and either adding oxygen or removing carbon dioxide, to help support the lungs and heart (known as extracorporeal membrane oxygenation (ECMO)
- Supportive measures such as turning the patient on their stomach and nutritional support may also help
There have so far been no effective pharmacological treatments developed to help treat ARDS.
ARDS can cause death as multiple organs fail. The elderly and people with other conditions are most likely to die from ARDS.
- Between 10–58 people per 100,000 develop ARDS depending on location and how the condition is reported
- 7.1% of people in critical care have ARDS, rising to 12.5% when patients are in intensive care for more than 24 hours
- Death rates range from between 27% and 45% of people with ARDS
- Young patients with ARDS following trauma are the most likely group of people to fully recover from ARDS over 6–12 months
Current and Future Needs
- Research is needed to develop pharmacological therapies for treatment
- Strategies looking at how to repair and regenerate the injured parts of the lungs are required
- Improvements should be sought in the treatment of ARDS patients in relation to ventilation techniques
- Further research is needed in new techniques and diagnostic tools
- Improving common working and standards is needed between nurses, physiotherapists and doctors in the intensive care unit