A government scientist has called for a halt to studies on experimental blood substitutes saying the products are linked to an increased risk of heart attack and death.

Scientists were working on creating artificial blood products to prolong life for wounded soldiers or car crash victims bleeding profusely. But scientists now say the blood substitutes increased the risk of death by 30 percent and increased the risk of heart attack by nearly three-fold.

A senior scientist at the National Institutes of Health, led an analysis of data from 16 trials of five fake blood products involving 3,711 patients, and uncovered the increased risks for heart attack or death.

The government wants human trials of fake blood products stopped until more animal studies are done.