Includes anaphylactic shock, septic shock and spinal cord injury (neurogenic shock). Inadequate organ perfusion is associated with vascular dilatation and hypotension, low systemic vascular resistance, inadequate afterload and a resulting abnormally high cardiac output. In anaphylaxis, vasodilatation is due to excess histamine release. Neurogenic shock is caused by traumatic or pharmacological blockage of the sympathetic nervous system, producing dilatation of resistance arterioles and capacitance veins, leading to relative hypovolemia and hypotension.In neurogenic shock, because of loss of vascular tone, JVP will fall.