Blood transfusions save lives in emergencies. However, blood isn't always immediately available because it needs refrigeration. Even after keeping it cool, blood expires after 42 days. Scientists have researched the possibility of synthetic blood for years, and researchers at Ohio State University and Washington University in St. Louis may have found at least a temporary solution: powdered blood.

Applications for Blood Substitute

Trauma patients who lose a lot of blood in accidents are often rushed to hospitals for blood transfusions. However, thousands die every year while they are en route to trauma centers. Service men and women also lose their lives on battlefields from gunshot wounds that cause internal bleeding and massive blood loss. In fact, shock from blood loss is the cause of about 70 percent of war fatalities.

Hemoglobin in red blood cells store and carry oxygen to tissues in the body. When people lose a lot of blood, their tissues begin to fail because they aren't receiving enough oxygen. This process puts the body into shock.

Supplying oxygen to these tissues is the main purpose of artificial blood. However, it can't fully replace human blood because it doesn't last in the bloodstream long enough. Normal red blood cells circulate for about 120 days. Synthetic cells only circulate for up to half of a day.

Although it doesn't replace human blood, the substitute could provide enough oxygen to keep trauma patients' bodies working until they receive a proper blood transfusion and medical treatment. On the battlefield, it could alleviate blood shortages and give medics an effective means of assistance until suitable treatment is viable.

Reusing Expired Human Blood

Researchers at Ohio State University are using expired human and cow blood to create the powder. They extract the hemoglobin from red blood cells so that the material can carry oxygen throughout the body.

At Washington University in St. Louis, researchers call their synthetic blood breakthrough ErythroMer. The tiny cells are about 2 percent the size of human red blood cells, and the powder looks similar to paprika.

Benefits of Powdered Blood

While human blood expires in 42 days with refrigeration, this powder can last for years at room temperature. It can even be stored in IV bags. When it's needed for a temporary transfusion, emergency responders and battlefield medics would only have to mix it with water to prepare for injection.

Another great benefit of the synthetic is that blood types don't matter. The reason is that hemoglobin doesn't have blood-type antigens. Because of this, the material would save time and make it easier to provide effective treatment in emergencies.

A Promising Start in Animal Trials

Researchers had promising results while using the powdered blood substitute on mice in a proof of concept study. In a mouse with only about half blood volume, the injected artificial blood delivered oxygen in the same way as normal blood. The material made it possible to resuscitate the animal after it went into shock.

More Studies Required

Despite these promising results, researchers need to conduct more studies to determine if the artificial blood is viable for human use. The next step toward this is confirming the results in a larger animal study. They also need to screen for and address toxicities before testing it for human efficacy and safety.

For example, the material contains iron, which could lead to damage in the surrounding tissue if it crosses blood vessel walls. One way to minimize this side effect is to increase the size of the hemoglobin-based molecules.

Outlook for Human Use

With further testing required and challenges to overcome, it could be 10 more years before this temporary synthetic blood is available for human use. A more permanent solution could be in the future if scientists can make the artificial red blood cells last longer in the bloodstream.