Hypovolemic shock 

Definition: This is shock caused by reduced blood volume. Reduction in circulating blood volume results in the reduction of the preload which leads to inadequate left ventricular filling, reflected as decreased left & right ventricular end diastolic volume and pressure. The reduced preload culminates in decreased cardiac output which leads to widespread tissue perfusion (shock).

Causes of hypovolumic shock include:

a) Haemorrhage 

b)  Diarrhoea & vomiting 

c) Burns 

d) Trauma

e) etc 

The effect of haemorrhage depends on the rate and amount of blood loss. Hypovolumic shock is the most common type of shock in clinical medicine .A normal healthy adult can lose 550ml (10%of blood volume) without significant symptoms.  But loss of 25% or more of the blood volume (N=1250ml) results in significant hypovolemia.

References

Bezabeh ,M. ; Tesfaye,A.; Ergicho, B.; Erke, M.; Mengistu, S. and Bedane,A.; Desta, A.(2004). General Pathology. Jimma University, Gondar University Haramaya University, Dedub University.