DENVER -- Doctors at Denver Health Medical Center believe a controversial "fake" blood product could someday save thousands of lives.

The blood substitute called PolyHeme was studied extensively in Denver, even though most of the patients didn't know they were getting the treatment.

The federal government waived the requirement of informed consent because it was the only way to test the product in an emergency situation.

Of the 720 trauma patients who were testing the product, more than 100 of them were in Denver. They were given PolyHeme instead of the traditional IV solution of saline. Paramedics randomly selected the patients who had suffered accidents that included significant blood loss.

Ambulances are unable to carry blood in their vehicles so scientists have long looked for a blood substitute.

PolyHeme is made from hemoglobin and delivers oxygen to the blood supply. It's long lasting and compatible with all blood types.

Researchers had hoped that using it instead of saline would dramatically increase patient survival rates.

The numbers were about the same, but lead researcher Dr. Gene Moore said he thinks the treatment shows promise.

At a press conference on Monday he said, "If you go climb a mountain in Colorado and get hurt and are taken to a hospital with just 10 beds, they are not going to have enough blood to support you."

Researchers believe the product could someday be used on the battlefield.

In addition to ethical concerns, the study also showed an increased risk for heart attacks.

Critics have said all human trials should be stopped until more studies are completed.