Multiorgan dysfunction syndrome: how water might contribute to its progression

Mulitorgan dysfunction syndrome (MODS) is one of the most frequent conditions encountered in intensive-care medicine. MODS is defined as total r partial loss oftwo or more organs with vital functions. The development of acute renal failure (ARF) in MODS leads to an additional aggravation with considerably higher hospital mortality than in other ICU patients with MODS. Whereas dissolved substances involved in the regulation of regional blood flow, endothelial cell injury, microvascular permeability, oxygnation, and nutrition of cells are at the focus of interest in MODS, hardly any scientific attention is paid to their main solvent water. An impaired renal water excretion and an icreased metabolic water volunme requiring exceetion interfere with diffusive and convective oxygen transport through the different fluid compartments. It will be shown first that the ratio of Uosm/Posm appears to be a reliable tools to assess overhydration in ARF. Secondly, the limits of urinary output in response to water intake will be considered. Furthermore, the metabolic water formation by an enhanced degradation of endogenous protein and fat will be discussed. Finally, the daily caloric intake is questioned with respect to energy expenditure and metabolic water formation.