The problem of blood loss

Modern surgeons know how to deal with blood loss. What's surprising is that most of the methods they use are hundreds, if not thousands of years old.

Why is blood loss dangerous?

Doctors worry about blood loss for very good reasons. If the body loses more than 20% of its blood, you could go into haemorrhagic shock, which is when the heart slows down and can't circulate enough blood around the body.

Blood pressure plummets when this happens and there’s a massive drop in body temperature. If the body loses more than 40% of its blood, all the organs start to shut down and death is likely.

A Japanese woman having surgery on her chest, with copious amounts of blood — Japanese manual depicting blood loss during a surgical procedure on the breast.

Techniques for limiting blood loss

One of the primary tasks of healers past and present has been to stop blood loss. Many of the techniques used to limit blood loss were developed long ago to treat wounds received in battle. And most of them are still used by surgeons.

Illustration of a naked man showing the different kinds of wounds that can be inflicted by weapons on his body. — The 'wound man' is found in early medical manuscripts shows the types of injury.

Surgical solutions for blood loss

Cauterisation has been used by many cultures around the world. To cauterise a wound, a metal tool was heated over a fire and applied to the wound, causing the blood to coagulate and seal off the damaged blood vessels.

A surgeon cauterising a man's wound with a hot iron in front of a fire — Thigh cauterisation with the different cauterising tools shown above. Medical text, Germany, 1530.

It was very painful, and the resulting burns caused a lot of tissue damage to an already injured body. But it could be done readily in the field and it was said to reduce the risk infection as well as blood loss.

Today, cauterisation would not be used on large wounds, but small-scale electrical cautery is still very useful for sealing off small blood vessels that may be causing internal blood loss.

Another ancient technique used to limit blood loss is ligation, where a piece of thread or wire called a suture is tied around a blood vessel to seal it. The method was known to ancient physicians such as Hippocrates and Galen, and was rediscovered and updated by the 16th century French military surgeon Ambroise Paré.

Print of Abroise Pare applying a ligature to a soldier's leg after amputation in the middle of a battlefield — Ambroise Paré, on the battlefield using a ligature for the artery of a soldier's leg. Engraving by C. Maurand c.1870s

The traditional 16th century method for sealing limbs after amputation was to use a combination of boiling oil and cauterization.

On one occasion, Paré ran out of oil and had to improvise. He used a tincture made of turpentine (which limited infection), egg yolk and oil of roses on the soldiers who still needed treatment. He found that the soldiers who had been treated with the traditional method were still in agony, but those that were treated with his tincture were doing much better.

The evidence from this impromptu field trial persuaded him to use ligatures to tie off large blood vessels such as arteries. But ligatures were not without problems. They tended to infect the wound, so they were not widely adopted by other surgeons.

The tourniquet was another 16th century method to control blood loss during amputation. This was a device or piece of material secured around a limb in order to limit the blood flowing down into the rest of the limb.

The difference between a tourniquet and a ligature was that the tourniquet was used to temporarily stop the flow of blood, whereas the ligature was more permanent.

Joseph Lister also recommended elevating the limb before using a tourniquet to make the surgical opening as blood-free as possible.

18th century surgeons amputating an arm and a leg while patients are seated in armchairs — Amputations of arm and leg with illustrations of where to position tourniquets. Engraving by F. Sesoni, 1749.

In 1904, Harvey Cushing created a pneumatic tourniquet, which compressed the underlying blood vessels by inflating a cylindrical bladder. This type of tourniquet could be applied and removed quickly and it decreased the incidence of nerve paralysis caused by depriving the blood vessels of blood for too long. Tourniquets are still used to keep the field of operation free from blood.

None of these techniques was of much help if there had already been extensive blood loss. Over the centuries several attempts were made to replenish the blood supply, either with animal or human blood, but they generally failed.

Safe blood transfusion only became possible after 1901, when Karl Landsteiner discovered that blood types had to be compatible in order for two people to share blood. It took a while for the technique to be perfected, and transfusion was not generally used until after the Second World War.

A soldier with a gun running on a large open hand with the outline of a bottle around him — Poster to recruit blood donors during the Second World War, England, 1943.

Blood transfusions not only saved lives on the battlefield and after accidents, they also allowed surgeons to perform surgeries that would otherwise have been too dangerous to attempt because of the amount of blood lost.

equipment used to control blood loss

Although the tools used to control blood loss may have changed over time, the principles remain the same. Open blood vessels have to be permanently sealed or temporarily closed. Blood needs to be replenished and circulated to prevent shock.