Acute Respiratory Distress Syndrome
Acute Respiratory Distress Syndrome Causes
Sepsis and the systemic inflammatory response syndrome (SIRS) are the most frequent predisposing factors associated with development of ARDS. These conditions may arise from the indirect toxic effects of neutrophil-derived inflammatory mediators in the lungs.
Acute Respiratory Distress Syndrome Definition
Acute respiratory distress syndrome (ARDS), also known as respiratory distress syndrome (RDS) or adult respiratory distress syndrome, is a serious reaction to various forms of injuries to the lung. This is the most important disorder that is caused by an increased permeability pulmonary edema. ARDS is a severe lung disease caused by different direct and indirect issues. It is marked by inflammation of the lung parenchyma leading to impaired gas exchange with concomitant systemic release of inflammatory mediators causing inflammation, hypoxemia and frequently resulting in multiple organ failure. This condition is life threatening and often lethal, typically requiring mechanical ventilation and admission to an intensive care unit. A less severe form of this disease is called acute lung injury (ALI). ARDS most commonly signified adult respiratory distress syndrome to differentiate it from infant respiratory distress syndrome in premature infants. However, as this type of pulmonary edema also arises in children, ARDS has gradually shifted to mean acute rather than adult. The differences with the typical infant syndrome remain the same.
Acute Respiratory Distress Syndrome Epidemiology
The annual incidence of ARDS is between 1.5 to 13.5 people per 100,000 in most of population. Its prevalence in the intensive care unit (ICU), mechanically ventilated population is much higher. Brun-Buisson and company reported in 1994 a prevalence of acute lung injury (ALI) of 16.1% percent in ventilated patients admitted for more than 4 hours. More than 50% of these patients may develop ARDS. Mechanical ventilation, sepsis, pneumonia, shock, aspiration, trauma (especially pulmonary contusion), drug reaction or overdose, major surgery, smoke inhalation, massive transfusions, fat emboli and reperfusion pulmonary edema after lung transplantation or pulmonary embolectomy may all trigger the development of ARDS. Pneumonia and sepsis are the most common triggers, and pneumonia arises in up to 60% of patients. Pneumonia and sepsis may be either results or complications of ARDS.
Acute Respiratory Distress Syndrome Treatment
Acute respiratory distress syndrome is typically treated with mechanical ventilation in the Intensive Care Unit. Ventilation is usually delivered through oro-tracheal intubation, or tracheostomy whenever prolonged ventilation (less than or equal to 2 weeks) is deemed inevitable. Appropriate antibiotic therapy should be administered as soon as microbiological culture results are available. Empirical therapy may be adequate if local microbiological surveillance is efficient. More than 60% ARDS patients experience a pulmonary infection either before or after the onset of lung injury.