Septic shock is an example of a particular type of shock known as distributive or hyperdynamic shock. In this condition, the patient demonstrates a high cardiac output and vasodilatation resulting in the maldistribution of blood flow. Despite a circulatory system that is working vigorously, the cells and tissues are unable to receive the appropriate nutrients and substrate necessary for appropriate functioning. The cells begin to convert from aerobic to anaerobic metabolism and a lactic acidosis develops.

Hemodynamically, these patients may have a decreased or nearnormal filling pressure (central venous pressure or pulmonary capillary wedge pressure) initially. When the vasodilatation (manifested by a reduction in the systemic vascular resistance) and maldistribution become severe enough, a relative hypovolemia occurs and the mean arterial pressure decreases. The cardiac output remains characteristically increased in this type of shock and is accompanied by increased venous oxygen saturation.