Hypovolemic Shock Caused by
One of the most common causes of circulatory shock is trauma to the
body. Often the shock results simply from hemorrhage caused by the trauma, but
it can also occur even without hemorrhage, because extensive contusion of the
body can damage the capillaries sufficiently to allow excessive loss of plasma
into the tissues. This results in greatly reduced plasma volume, with resultant
Various attempts have been made to implicate toxic factors released
by the traumatized tissues as one of the causes of shock after trauma. However,
cross-transfusion experiments into normal animals have failed to show
significant toxic elements.
In summary, traumatic shock seems to result mainly from
hypovolemia, although there might also be a moderate degree of concomitant
neurogenic shock caused by loss of vasomotor tone, as discussed next.