Acute respiratory distress syndrome (ARDS) is a condition in which there is rapid onset of injury to multiple organs manifested as respiratory failure. It is common in intensive care patients and occurs via a myriad of direct or indirect mechanisms of lung injury. 

When a NIH sponsored study of ARDS was planned in the 1970 though the estimated cases was set at 75 per 100000 population. 

The prevalence is occurring commonly in older adults.

The alveoli are the small structures wherein the gas exchange occurs. Usually, a very marginal layer of tissue separates the air in the alveoli from the blood vessels in the capillaries. This membrane allows the oxygen from the air to pass into the bloodstream and the other way round; that is the carbon dioxide from the bloodstream gets passed into the air.
In ARDS the small alveoli that are responsible for gas exchange gets damaged just like the walls of the capillaries. This damage is inclusive of leakage of fluid, proteins, and blood cells into the air sacs. The formation of fluid thereby impedes the expansion of the lungs in the process of taking in oxygen.

There are two main stages of ARDS: There are two main stages of ARDS:
Exudative phase: During this stage fluid and proteins and blood cells are spilling from the damaged capillaries into the alveoli. This fluid elevates lung stiffness and accounts for their less ability to expand.

Proliferative phase: This stage involves the process of healing of the lungs from the damage caused in the body. This repair process can however at the same time lead to formation of scars in the lungs which can make it even more difficult for the oxygen to be passed to the bloodstreams. 

Pneumonia: A severe infection by bacteria, viruses, or fungi can cause severe inflammation in the lungs resulting in ARDS. 
 
Near-drowning: Respiratory tract simply inhales water and this can cause ARDS. 
 
Toxic inhalation: Smoking or inhalation of any other harmful gases can lead to direct toxicity of the lung epithelium. 
 
Fat embolism: After the occurrence of the long-bone fractures injuries or any trauma, fat globules may find their entrance into the blood. 
 
Sepsis: Sepsis is a condition that predisposes mortality as well as ARDS as a result of systemic inflammation. 
 
Pancreatitis: The enzymes and inflammatory mediators that will be released by the inflamed pancreas can be able to reach the lungs and cause damage on the affected tissue. 

The prognosis will depend on several factors; the cause; the patient’s age; the number of syndromic organs; and whether the patient suffers from chronic conditions. 

Age group: 

ARDS is commonly seen in elderly population above 65 years of age. 

Respiratory assessment  

Cardiac assessment  

Sepsis  

Pneumonia  

Chronic lung diseases 

Pancreatitis  

Severe burns  

ARDS generally manifests in patients within a week of exposure to a known clinical event or the onset or worsening of breathlessness. 
It may develop very rapidly usually within few hours to few days following the precipitating factor (e.g. sepsis, pneumonia, trauma, or aspiration). 
 
ARDS patients commonly arrive in ICU with acute breathlessness (dyspnea) and increased respiratory rate (tachypnea). 
 
Hypoxemia is a common and often profound normoxia oxygen-insensitive characteristic. 
Chest x-ray often is normal or may show bilateral diffuse alveolar infiltrates on the lung. 

Treatment of Underlying Cause:
Search for and resolve the primary cause of ARDS that resulted in the disease, such as pneumonia or sepsis or trauma or other cause.

Reduce blood sugar as well as treat any other systemic infections or inflammatory processes.

Supportive Care:

Mechanical Ventilation: Mechanical ventilation therefore becomes a mandatory intervention for the patients of ARDS.

Ventilation Strategies: The different ventilatory parameters are also used eg. low tidal volume ventilation being 6 ml/kg of predicted body weight; plateau pressure<30 cm H2O and higher PEEP.

Extracorporeal Membrane Oxygenation (ECMO): If a patient in the intensive care unit is in a life-threatening situation and responds poorly to the mentioned therapy, ECMO may be applied.

Oxygen Therapy: If the oxygen compensation is inadequate, either supplemental oxygen or mechanical ventilation should be used.

Do not give high oxygen concentrations (hyperoxemia condition) which can be harmful. 

Fluid Management:

Ensure the partaker is not in fluid overload or fluid deprivation.

Do not overhydrate and avoid at all costs fluid overload since this worsens the condition of lung function and oxygenation.

Pharmacological Therapies:

Sedation and Analgesia: The care assistant should be able to relieve pain and manage mechanical ventilation.

Neuromuscular Blockade: Perhaps this may be done to optimize patient-ventilator synchrony.

Vasoactive Medications: Supporting measures may be necessary if hemodynamic instability is present.

Nutritional Support:

Provide food for the children to eat to improve and strengthen their immune systems.

If enteral feeding is feasible and would not increase the risk, the enteral feeding should then be prioritized.

Prevention of Complications:

Infection Control: Frequent hand washing, use of protective gloves, incineration of contaminated items, isolation of already infected fishes and sanitation. 

Deep Vein Thrombosis (DVT) Prophylaxis: Prevention of DVT and pulmonary embolisms using anticoagulant therapy. 

Critical Care/Intensive Care

Temperature and Humidity Control: It is important to maintain the place at the temperature and humidity that is comfortable for the individuals. High or low temperature and high humidity can also be the cause of strain to the respiratory system. It is recommended to use air conditioners and dehumidifiers/humidifiers as desired to maintain the needed conditions. 
 
Allergen Control: Dusts and pollen in the air and pet dander must be minimized. They can minimize breathing discomfort to susceptible people. Vaccuming at least once a week with a high efficiency particulate air (HEPA) filter vacuum cleaner; Using HEPA-filtered air purifiers; and Restricting pets from rooms used for sleeping, especially child bedrooms. 
 
Nutritional Support: People recovering from the disease should eat healthy food. If the patient is having food and fluid restrictions, ensure that the type of food and fluids being offered is maintained. 

Critical Care/Intensive Care

Methylprednisolone  

High-dose methylprednisolone has been reported in trials involving patients with ARDS who have persistent pulmonary infiltrates, fever, and high oxygen demand after clearing pulmonary or extrapulmonary infections. 

Critical Care/Intensive Care

Recognition and Diagnosis:
Early and accurate diagnosis of ARDS based on clinical criteria: Example Started suddenly with bilateral opacities in the chest on imaging and respiratory failure and it was not well explained by cardiac failure or fluid overload).

Supportive Care: Oxygen Therapy: Preoxygenation for seven or more cycles or until oxyhemoglobin desaturation occurs should be instituted with a reservoir of 100% oxygen.

Nutritional Support: Provide an optimal quantity of nutritional intake required in the healing process.

Treatment of Underlying Cause: 

Identify and correct the source leading to ARDS. eg. sepsis, trauma, pneumonia.

Pharmacological Interventions: There is no specific pharmacologic therapy for ARDS itself, but treatment is possible for several conditions that may cause ARDS indirectly or ARDS complications such as pneumonia and sepsis. eg. fluid for edema), etc.

Monitoring and Adjustments: Change in mechanical ventilation and manual ventilator therapy processes based on patient feedback and progression in the illness.

Long-term Follow-up: Long-term complications: Monitor for long-term complications, such as pulmonary fibrosis chronic pulmonary disease, cognitive impairment and ensure that they receive follow-up treatment.