Circulatory collapse: physiopathologic considerations.

Abstract

Hypovolemy is the most frequent cause of a shock in the traumatized patient. This fact has motivated us to carry out a revision of the physiopathologic changes occurring in these cases.
The reviewed literature coincides in the opinion that diminishing of the intravascular volume, the alteration of myocardial functions and the insufficient histic perfusion are its main characteristics. Its is useful to consider the alterations of the circulatory system, composed by its three main elements: the cardiac pump, the volume of running blood and the vascular system, because every one of these components suffers alterations as a result of the critical diminishing of the nutritional blood flow. We concluded that the shock shouldn't be identified with an arterial hypotension, although the arterial hypotension uses to be present, because the blood flow not only depends on the perfusion pressure but on the vascular resistance too, and it can diminish under the critical necessary levels for the cellular viability, and nevertheless, the arterial tension is kept through an increase of the total systemic resistance. That is why it is possible the occurrence of a circulatory shock without the presence of an arterial hypotension.