Acute respiratory distress syndrome epidemiology and demographics

Overview
Acute respiratory distress syndrome is relatively uncommon, occurring in 1.5-13.5 people per 100,000. It can be associated with a number of trigger conditions such as sepsis, aspiration, and pneumonia.

Epidemiology

 * The annual incidence of ARDS is between 1.5 to 13.5 people per 100,000 in the general population
 * Its incidence in the intensive care unit (ICU), mechanically ventilated population is much higher. Brun-Buisson et al. (2004) reported a prevalence of acute lung injury (ALI) (see below) of 16.1% percent in ventilated patients admitted for more than 4 hours. More than half these patients may develop ARDS.
 * Mortality varies from 30% to 60%. Usually, randomized controlled trials in the literature show lower death rates, both in control and treatment patients. This is thought to be due to stricter enrollment criteria. Observational studies generally report 50%-60% mortality.

Demographics
Things that may trigger ARDS:
 * Mechanical ventilation
 * Sepsis
 * Pneumoniashock
 * Aspiration
 * trauma (especially pulmonary contusion)
 * Major surgery
 * Massive transfusionssmoke inhalation
 * Drug reaction or overdose
 * [[Fat emboli]
 * Reperfusion pulmonary edema after lung transplantation or pulmonary embolectomy
 * Pneumonia and sepsis are the most common triggers, and pneumonia is present in up to 60% of patients. Pneumonia and sepsis may be either causes or complications of ARDS.
 * Elevated abdominal pressure of any cause is also probably a risk factor for the development of ARDS, particularly during mechanical ventilation.