If the human brain (an astronaut’s brain in this case) is deprived of oxygen, irreparable damage occurs within about 4 minutes. .. at body temperature. But under conditions of hypothermia (low body temperature), damage occurs much slower.

Hypothermic anesthesia lowers the body temperature to 68-77F (20-25C) and allows blood flow to the brain to be stopped for up to an hour. https://en.wikipedia.org/wiki/Deep_hypothermic_circulatory_arrest

https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.sciencedirect.com%2Ftopics%2Fmedicine-and-dentistry%2Fdeep-hypothermic-circulatory-arrest&psig=AOvVaw0D4ZkKY1kdEkCSi1gvAmRQ&ust=1669911847262000&source=images&cd=vfe&ved=0CBEQjhxqFwoTCNiL3cWo1vsCFQAAAAAdAAAAABAJ

There is evidence from rescued avalanche suffocation victims that hypothermia is neuro-protective. https://www.resuscitationjournal.com/article/S0300-9572(16)30114-9/pdf#:~:text=Hypothermia%20is%20one%20factor%20in,make%20a%20comparison%20to%20drowning

There are anecdotal cases of downing victims immersed in cold water who have been resuscitated after 30 minutes. The longest time from hypothermic cardiac arrest to return of spontaneous circulation is almost 7 hours. https://www.sciencedirect.com/science/article/pii/S0300957214005243

Back to the astronauts: Most possible fatal events during EVA have cerebral hypoxia as the ultimate cause of death. If an EVA goes sour and an astronaut suddenly loses all oxygen supply, rescue and successful resuscitation could be enhanced by induced hypothermia.

Space suits have a Liquid Cooling and Ventilation Garment (LCVG).

Suppose I had a structural suit failure during EVA, leading to complete loss of pressure. My only hope for survival would be re-pressurization. 4 minutes is not very long for my EVA partner to manhandle me into an airlock. If my LCVG could lower my body temperature during the rescue, this could increase the time to brain death for a few more minutes. I’d go for it. Nothing to loose.

This is an unusual proposal, but it is for a very unusual situation. Hypoxia is treated with oxygen and ventilation, which is not available during the EVA depressurization incident. Hypothermia induction using a custom designed total body refrigeration suit is not usually available as an emergency alternative. But this alternative is available in an EVA suit.

Question: What policies and capabilities are in place to induce hypothermia for the purpose of reducing hypoxic brain damage in EVA astronauts? If not, why not?