Multiple Organ Oxygen Supply-Demand Relationships and Redistribution of Flow

Multiple systems organ failure (MSOF) is by far the most common cause of death in present day intensive care units (ICUs) [1]. While a unifying process to explain this phenomenon has not been defined, there is reason to suspect that O2 deprivation may be a common etiologic factor. Indeed, there is little question that O2 deprivation produces cell death in mammals [2], and most patients who develop MSOF experience one or more episodes of hypoperfusion before organ failure is manifest clinically [3]. However, the role of O2 deprivation in the pathogenesis of MSOF is poorly defined, in part because “critical O2 deprivation” has defined precise identification. In this chapter we will briefly review physiologic phenomena associated with O2 deprivation at the whole body and individual organ levels.