Blood circulates continuously throughout the body, allowing communication between distant tissues. Plasma is a clear, straw-colored fluid that suspends different types of blood cells. Plasma expanders are high molecular weight agents that boost plasma volume by increasing osmotic pressure. They are used to treat hemorrhage or shock by replacing fluid lost through illness, trauma, surgery, burns or tissue damage. Volume expanders include crystalloids like saline and ringers solution, and colloids like albumin, dextran, and gelatin. They work by increasing plasma osmotic pressure and drawing water into plasma from tissues.