Crystalloid required for replacement of 300ml of blood loss is:

For crystalloid replacement ratio is 3:1 For colloid replacement ratio is 1:1 Distribution of Body fluids. Total body fluid accounts for about 60% of the lower body weight in male and 50% of the lower body weight in females. Intracellular fluids accounts for 40% of total body fluids and extracellular accounts for 20% of which only 5% is intravascular. Thus volume of blood accounts for 6% to 7% of body weight and only 11-12% of total body fluid. The meager distribution of total body fluid in the vascular compament is an impoant factor in the intolerance to blood loss. Plasma vs interstitial fluid Extracellular fluid accounts for about 20% of the total body fluid, and is composed of extra vascular (interstitial) and intravascular (plasma) fluid compament Comparison of interstitial fluid and plasma volumes Plasma volume is about 25% of interstitial fluid volume. This relation is impoant for understanding volume effects of two types of fluid crystalloids and colloids. Crystalloid achieves a rapid equilibrium throughout the extracellular fluid compament thus only 25% remains intravascular 75% distribute in extracellular space. Colloids does not cross blood vessels thus remains in the intravascular space.