The Significance Of Dextran In History

In the World War Ⅱ, soldiers injured on the battlefield often died of very low blood pressure before they could reach hospital. But there was a dramatic change when the Korean War happened. There was a miracle life saver around – dextran.

Dextran is a complex carbohydrate, that is, a chain of sugar molecules strung together. It is a white powder which does not dissolve in water. Instead it absorbs water and swells into a loose jelly. So how did it help in the Korean War?

When a soldier is injured, he loses a lot of blood very quickly. This leads to loss of electrolytes and oxygen, and a sharp drop in blood pressure, endangering his life. He needs a blood transfusion immediately. But he cannot just be given any blood. If the blood groups do not match, there can be terrible complications.

During World War II, doctors tried transfusing plasma. Plasma is blood without any cells in it. It does not cause complications, and can immediately push up the blood pressure and replenish electrolytes. However, plasma can spoil easily, so it must be kept in ice all the time. An in the battlefield, where do you store plasma?

That’s where dextran helps. It can be carried dry, quickly mixed with water and salt and transfused to the patient. It pushes up the blood pressure immediately, while the saline helps restores some electrolytes. The patient can then be carried to a hospital where he can receive a proper blood transfusion.

How dextran was discovered
Dextran is made by bacteria. It is found in a place where you wouldn’t like it to be – dental plaque! It’s also found in small amounts in curd, and a fermented drink called kefir. But what was needed was a way to make dextran in large amounts.

In the 1940s, Allene Jeanes was a scientist at the USA’s Northern Regional Research Lab. A soft drink company had sent her a sample of their product, which had mysteriously become thick and gooey. She soon found that a bacterium had converted the sugar in the soda to dextran. Perhaps the bacteria had come from some worker’s dental plaque!

She found that the bacterium could be grown in the lab. It could grow in a vat of sugar solution, and make lots of dextran. That was then purified, dried, and sent on to Korea. There it would help soldiers survive the journey from battlefield to hospital, where they could get healed completely.

The Korean War ended in 1953, leaving Korea divided into two countries. But there was a clear winner of that war – dextran.