Gastrointestinal tract dysfunction in critical illness: pathophysiology and interaction with acute lung injury in adult respiratory distress syndrome/multiple organ dysfunction syndrome.

The adult respiratory distress syndrome (ARDS), a common complication of critical illness, is associated with a > 50% mortality rate. Refractory respiratory failure is, however, an uncommon cause of mortality in these patients. Most deaths are due to a syndrome of relentless organ dysfunction accompanied by abnormal organ system interactions, collectively referred to as the multiple organ dysfunction syndrome (MODS). MODS is associated with two chief pathophysiologic derangements: a) the unregulated activation of systemic inflammatory cascades; and b) alterations of oxygen uptake (VO2)-oxygen delivery (DO2) relationships. Current concepts regarding the pathophysiology of MODS, specifically its relationship to unregulated systemic inflammation and alterations in VO2-DO2 alterations, are discussed. Within this framework, current and future areas for investigation that may result in mechanism-specific innovations with the potential to interrupt events mediated by gastrointestinal dysfunction that lead to MODS are presented.