EurekAlert has a report on the early stages of a promising new way forward in inducing suspended animation – using hydrogen sulfide, the stinky gas that can kill workers who encounter it in sewers.

“When adminstered to mice in small, controlled doses, within minutes it produces what appears to be totally reversible metabolic suppression,” says Warren Zapol, MD, Chief of Anesthesia and Critical Care at Massachusetts General Hospital and senior author of the study from the April 2008 issue of the journal Anesthesiology.  “This is as close to instant suspended animation as you can get, and the preservation of cardiac contraction, blood pressure and organ perfusion is remarkable.”

In all the mice, metabolic measurements such as consumption of oxygen and production of carbon dioxide dropped in as little as 10 minutes after they began inhaling hydrogen sulfide, remained low as long as the gas was administered, and returned to normal within 30 minutes of the resumption of a normal air supply.  The animals’ heart rate dropped nearly 50 percent during hydrogen sulfide adminstration, but there was no significant change in blood pressure or the strength of the heart beat.  While respiration rate also decreased, there were no changes in blood oxygen levels, suggesting that vital organs were not at risk of oxygen starvation.

Apart from the obvious benefits of suspended animation for interstellar travel, or those long Sunday afternoons, the state could also be induced in victims of serious accidents en route to hospital to prevent them expiring – but there’s a way to go yet:

“It could be that inhaled hydrogen sulfide will only be useful in small animals and we’ll need to use intravenous drugs that can deliver hydrogen sulfide to vital organs to prevent lung toxicity in larger animals” Zapol added.