Most seriously affected organ in shock is
a. Shock is defined as tissue hypoperfusion that is insufficient to maintain normal aerobic metabolism. The initial insult, whether hemorrhage, injury, or infection, initiates both a neuroendocrine and inflammatory mediator response.
b. Hemorrhagic shock is seen most often clinically; bleeding and resuscitation produce a "whole body" ischemia-reperfusion injury. The major mechanisms achieving this response are:
i. Prompt increase in cardiac contractility and peripheral vascular tone via the autonomic nervous system,
ii. Hormonal response to preserve salt and intravascular volume, and
iii. Changes in the local microcirculation to regulate regional blood flow.
c. With substantial physiologic compensatory mechanisms for small volume blood loss, predominantly through the neuroendocrine response, hemodynamics may be maintained.
d. With persistent hypoperfusion with low cardiac output, regional tissue hypoperfusion and progressive tissue and microcirculatory changes induce cardiovascular decompensation. This progression to the irreversible phase of shock is often insidious and recognized only in retrospect. Sufficient tissue injury and cell death have occurred to this point that continued volume resuscitation fails to reverse the process.
e. The decrease in blood supply is first seen to splanchnic circulation , skin skeletal muscles and among visceral organ to the kidney.