Dr. Hasan Alam, a trauma surgeon at the Harvard-affiliated Massachusetts General Hospital (MGH), believes that he is ready to take the next step in his research on suspended animation: human trials. His team has already demonstrated the technique in close to 200 pigs with a 90% success rate.
Many patients with severe blood loss from gunshot wounds or car accidents die before they are able to reach the operating room. The heart can only survive for about 20 minutes without blood, and without blood the brain dies in 5 minutes. Dr. Alam believes he can extend the survival time through suspended animation, or "asanguineous hypothermic metabolic arrest." This
process involves stopping the heart and cooling the body using an
infusion of a chilled artificial solution originally developed to
protect organs being transported for use in transplant surgery. The patient's core temperature reaches 10 degrees C. At this point, the patient has no detectable pulse or electrical activity in the brain. To
revive the patient, the potassium level is restored to normal, warm
blood is transfused, and if necessary, an electrical shock is
applied to the heart to restore its normal rhythm.
In the pig studies
that have been performed, the researchers induced severe blood loss by
cutting a major vein and artery in the abdomen. The animal was then allowed to bleed for 30 minutes to simulate the transit time needed to get to a hospital. Then, a lethal cut is made in the aorta. The animal is allowed to bleed for another 5 minutes before the cooling process begins. In
total, about 50% of the total blood volume is lost (scaled to humans,
this is equivalent to 2.5 liters). The animal is kept at 10 degrees C
for 60 minutes while its injuries are repaired, and the animal is then
revived. Despite having no pulse for one hour, the animals show no signs of any neurological damage afterwards.
According to SMH,
Dr. Alam is requesting that his suspending animation protocol
automatically be used on all patients arriving at MGH who have lost so
much blood before coming to the hospital that they would likely die
with conventional care. The review process for such a proposal typically takes several months.