Shock or Circulatory Collapse:
A condition of profound hemodynamic and metabolic disturbance characterized by failure of the circulatory system to maintain adequate perfusion of vital organs.
Causes:
(i) Inadequate blood volume (hypovolemic shock)
(ii) Inadequate cardiac function (cardiogenic shock)
(iii) Inadequate vasomotor tone (neurogenic shock and septic shock)
Hypovolemic shock or hematogenic shock or oligemic shock:
Shock resulting from insufficient blood volume for the maintenance of adequate cardiac output, blood pressure and tissue perfusion.
Without modification the term refers to absolute hypovolemic shock caused by acute hemorrhage or excessive fluid loss.
Relative hypovolemic shock refers to a situation in which the blood volume is normal but insufficient because of widespread vasodilation as in neurogenic or septic shock.
Clinical characteristics:
1. Hypotension
2. Hyperventilation
3. Cold
4. Clammy, cyanotic skin
5. A weak and rapid pulse
6. Oliguria
7. Mental confusion
8. Combativeness or anxiety
