Adult Respiratory Distress Syndrome

What is this Condition?

In this syndrome, fluid builds up in the lungs and causes them to stiffen. This impairs breathing, thereby reducing the amount of oxygen in the capillaries that supply the lungs. When severe, the syndrome can cause an unmanageable and ultimately fatal lack of oxygen. However, people who recover may have little or no permanent lung damage. What Causes it?

Adult respitatory distress syndrome is caused by:

• aspiration of stomach contents into the lungs

• infection, injury (such as a lung contusion, head injury, bone fracture with fat emboli), or too much oxygen

• viral, bacterial, or fungal pneumonia or microemboli (fat or air emboli or disseminated intravascular coagulation)

• drug overdose (barbiturates or narcotics) or blood transfusion

• smoke or chemical inhalation (nitrous oxide, chlorine, ammonia)

• hydrocarbon and paraquat (a toxic herbicide) ingestion

• pancreatitis or uremia

• near-drowning.

If the body can't remove the accumulated fluid, swelling within the lungs and narrowing of their airways develops. Oxygen deficiency is caused by fluid accumulation.

What are its Symptoms?

Adult respiratory distress syndrome initially produces rapid, shallow breathing and shortness of breath within hours to days of the initial injury. Oxygen deficiency develops, causing an increased drive for breathing. Because of the effort required to expand the stiff lung, the person's chest retracts during breathing. As the person gets less oxygen, he or she becomes restless, apprehensive, and mentally sluggish.

Severe adult respiratory distress syndrome causes an overwhelming deficiency of oxygen which, if uncorrected, results in very low blood pressure, decreasing urine output and, eventually, heart attack.

How is it Diagnosed?

Arterial blood gas analysis helps detect the syndrome. Other tests include pulmonary artery catheterization and chest X-rays.

Tests must rule out other lung disorders. To establish the cause of the illness, lab work includes cultures of sputum and blood specimens to detect infections; a toxicology screen for drug ingestion; and, if pancreatitis is a possibility, a serum amylase determination. How is it Treated?

When possible, treatment tries to correct the underlying cause of adult respiratory distress syndrome and to prevent progression and potentially fatal complications. Supportive medical care consists of administering humidified oxygen by a tight-fitting mask. Oxygen deficiency that doesn't respond adequately to these measures requires the use of a mechanical ventilator. Other supportive measures include fluid restriction, diuretics, and correction of electrolyte and acid-base abnormalities.

When adult respiratory distress syndrome requires a mechanical ventilator, drugs such as sedatives, narcotics, or the neuromuscular blockers Tubarine or Pavalon may be given to minimize restlessness and ease breathing.

When adult respiratory distress syndrome is caused by fat emboli or chemical injuries to the lungs, a short course of high-dose steroids may help if given early. Intravenous fluids and drugs may be given to maintain blood pressure. Infections require antibiotics.