Roth's technique replaces inhaled oxygen with hydrogen sulfide. Normally toxic, hydrogen sulfide has the curious ability to alter the mammalian metabolism when applied in a cold environment. Using this technique, Roth has already managed to place lab animals into suspended animation, and safely bring them back. When in a suspended state, the body can better cope with the deadly oxygen deprivation that results from shock, massive blood loss, and heart attacks. Source
Roth's technique replaces inhaled oxygen with hydrogen sulfide. Normally toxic, hydrogen sulfide has the curious ability to alter the mammalian metabolism when applied in a cold environment. Using this technique, Roth has already managed to place lab animals into suspended animation, and safely bring them back. When in a suspended state, the body can better cope with the deadly oxygen deprivation that results from shock, massive blood loss, and heart attacks.
Source