Blood loss

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Key Terms

Cautery- The use of heat to seal blood vessels and stop bleeding

Ligature- A thread tied around a blood vessel to stop bleeding

Shock- When there isnt enough blood in the circulatory system to keep the body working properly

Transfusion- The process of giving blood from a donor to the patient

Background Information

Blood-loss has always been a major problem in surgery as it distorts how much the surgeon can see and can also lead to shock which will cause death.

During the 17th century there were experiments with blood transfusions using blood from animals and humans

Once anaesthetics and antiseptics made it possible to perform complex operations there was a renewed drive to solve the problem of blood loss and replacing lost blood

Controlling blood loss

The usual way to deal with wounds or amputations was to seal the blood vessels by placing a hot iron onto the wound or pouring hot oil over it. This is called cautery

In the 16th century Ambroise Pare developed metal clips to place on arteries during an operation

Ambroise Pare also tried using silk threas to tie blood vessels after and amputation instead of using heat

Ligatures did not always stop the bleeding though if they were not tied correctly

Cautery continued to be the main way of dealing with bleeding until Lister developed Pares ideas in the 19th century

Lister introduced the use of catgut instead of silt to use as stitches. It could be sterilised and would dissolve after several days in the body so would be no thread dangling from the wound.

Blood types

There was problems with transfusing blood from an animal into a human

This problem was solved in 1901 by Karl Landsteiner, he suggested that there were different blood groups

Landsteiner showed that some of the blood types were incompatible and would have fatal consequences if mixed

However even with this discovery there was still the problem that a donor needed to be present to provide the blood

The problems with transfusions

Clotting- blood starts to clot as soon as it leaves the body, it would block up the transfussion tubes and stop the transfusion

Availability- clotting meant that the blood could not be stored so transfusions had to be done with the donor attached to the recipient

Immune response- Sometimes the donor blood would cause the recipients red blood cells to clump together. which would often lead to death

Storing blood

in 1915 an American Richard Lewisohn found that adding sodium citrate stopped blood from clotting

Richard Weil found that this blood could then be stored in refrigerated conditions

in 1916 Francis Rous and James Turner found that adding citrate glucose allowed the blood to be stored for longer.

This meant that during war the army could ask for donations of blood to treat the wounded

The first blood epot was established in 1917 for the battle of Cambrai.