Influence of Acute Respiratory Distress Syndrome (ARDS) and Severe Sepsis on sRAGE Levels in ICU Patients

• sRAGE levels in the plasma from ICU patients within the first 24 hours after onset of ALI/ARDS or severe sepsis/septic shock [ Time Frame: within the first 24 hours ] [ Designated as safety issue: Yes ]
  

• To describe kinetics of evolution of sRAGE levels in ICU patients with ALI/ARDS and severe sepsis/septic shock [ Time Frame: in UCU patients ] [ Designated as safety issue: Yes ]
  

BACKGROUND:

The receptor for advanced glycation end products (RAGE was recently identified as a promising new marker of alveolar type I cell injury. RAGE is a member of the immunoglobulin superfamily that acts as a multiligand receptor and is involved in propagating inflammatory responses. While the precise function of RAGE remains unclear, the elevated levels of RAGE, and its soluble isoform sRAGE, correlate with severity of ALI/ARDS in human and animal studies, and RAGE levels could reflect impaired alveolar fluid clearance. Thus, it is possible that elevated levels of RAGE in ALI/ARDS derive in part from RAGE's role in systemic inflammatory cascades rather than purely from its release from alveolar type I cells.

DESIGN NARRATIVE:

This observational prospective clinical study will describe and compare sRAGE levels in the alveolar edema fluid and in the plasma from ICU patients enrolled within the first 24 hours after onset of ALI/ARDS and/or severe sepsis/septic shock, and from patients under mechanical ventilation (control group). Edema fluid and plasma samples will be collected simultaneously on day 1, day 3, day 6, and day 28 (or at ICU discharge), in order to describe kinetics of evolution of sRAGE levels. Undiluted pulmonary edema fluid samples will be collected in intubated patients only, and blood samples will be gathered from an indwelling arterial catheter. The concentrations of sRAGE will be measured in duplicate by ELISA.