Acute Pulmonary and Systemic Inflammation in Mechanically Ventilated Intensive Care Patients

Acute respiratory distress syndrome (ARDS) is a devastating form of acute lung inflammation, that may be caused by a variety of insults with pulmonary and systemic infectious disease being the most common predisposing factor. Sepsis, on the other hand, represents the systemic inflammatory response to an invading pathogen, which may inflict damage upon the host through organ dysfunction. ARDS and sepsis are heterogenous clinical conditions that have a high mortality, and both diseases involve a complex interplay of different inflammatory mediators and cell types. It has been suggested that locally released inflammatory mediators pass from the lungs into the bloodstream following ARDS, triggering systemic inflammation. Conversely, it is possible that severe systemic inflammation may lead to ARDS by an influx of inflammatory mediators from the bloodstream to the lungs. However, the time course and the possible pathways for this transmission of disease have yet to be established.

Investigators hypothesize that:

1. Primary systemic inflammation is followed by a secondary pulmonary inflammatory response
2. Primary pulmonary inflammation is followed by a secondary systemic inflammatory response
3. Both primary and secondary inflammatory responses are characterized by the appearance of pro-inflammatory cytokines, inflammatory cells and production of collagen-like proteins (termed 'lectins')
4. The inflammatory response is most pronounced in the primary afflicted compartment.