Severe hypovolemic shock occurs when blood volume less is -
Hypovolemic shock

Hypovolemic shock is the most common form of shock.



This is due to a decrease in blood volume either by the loss of blood or plasma.
Grading of hypovolemic shock


Mild hypovolemia → When volume loss is less than 20%. There is generally mild tachycardia but relatively few external signs.
Moderate hypovolemia → When volume loss is between 20-40%. Normal blood pressure is maintained
	in the supine position, but there are postural hypotension and tachycardia on erect posture.
Severe hypovolemia → When volume loss is > 40%. The classical signs of shock appear i.e., marked tachycardia, hypotension, disorientation.
> 10 %
> 20 %
> 30 %
>40%