Distributive shock is defined as a medical condition in which:

• A. A lack of blood flow due to external bleeding
• B. A medical condition in which the distribution of blood flow in the small vessels results in an adequate supply of blood to the body's tissues and organs
• C. Failure of the heart to pump enough blood
• D. Obstruction of a large vessel

Answer: (B)

Distributive shock is about how blood is distributed through the microcirculation, not simply how much blood is in the vessels. In this type of shock, widespread vasodilation and increased capillary permeability cause blood to pool in the venous system and the smaller vessels, so tissues and organs end up receiving less blood flow than they need. Even if the total blood volume or the heart’s pumping power seems adequate, the distribution is off, leading to tissue hypoperfusion and potential organ dysfunction.

So the idea that the distribution of blood flow in the small vessels guarantees an adequate supply to tissues isn’t accurate for distributive shock. The hallmark is insufficient perfusion despite circulating volume, due to misdistribution.

Other shock types present differently: external bleeding reduces circulating volume (hypovolemic shock); the heart not pumping enough (cardiogenic shock); and a blockage of a large vessel (obstructive shock).