Diagnosis and Treatment of the Septic Microcirculation

Shock has typically been classified into four types: Hypovolemic, cardiogenic, obstructive, and distributive. The first three categories are associated with a decrease in cardiac output, leading to tissue hypoxia. Distributive shock, such as septic shock, results from abnormal distribution of normal or increased cardiac output, secondary to microcirculatory dysfunction. Severe disruption of the microcirculation during sepsis results in a pathologic heterogeneity in microvascular blood flow that occurs as a consequence of the shutdown of weak microcirculatory units. This implies that oxygen transport is shunted from the arterial to the venous compartment, leaving the microcirculation hypoxic, and is the main pathogenic feature of distributive shock. Such a scenario results in maldistribution of microvascular blood flow and a mismatch between oxygen delivery and oxygen demand in different tissues that seems to be the first step in the progression to organ failure [1].