Answer: No, the capability is not in place to induce therapeutic hypothermia to reduce hypoxic brain damage in a EVA depressurization, or for treating post hypoxic cerebral edema. But maybe it should be considered.“… hypothermia would apparently be of great value in the treatment of posthypoxic cerebral edema in space … adequate total body cooling might be attained with a water-cooled space suit.” https://ntrs.nasa.gov/citations/19670023576

This could potentially slow hypoxic brain damage to allow more favorable prognosis once the astronaut can be re-pressurized.

However, existing LCVC suits do not have the capacity to induce rapid hypothermia. Maybe they could, with minor modification. The Apollo A7L suit could dissipate 2000 BTU/hr. https://en.wikipedia.org/wiki/Liquid_cooling_and_ventilation_garment. This is the equivalent of 500,000 calories, enough to reduce 70kg of astronaut by 7*C in an hour. Not fast enough.

However, if the 2.7 Kg of water in the suit’s LCVC reservoir https://www.hq.nasa.gov/alsj/ALSJ-FlightPLSS.pdf were dumped into the depressurized suit, flash evaporation would provide 1,450,000 calories of evaporative cooling. This is more than enough refrigeration to induce hypothermia of 30*C, and thereby double the astronaut’s hypoxic survival time. Since the “dump” is both triggered by, and powered by, the vacuum in the depressurized suit, a fail-safe mechanism should be practical.

Basic design research would need to be done on human-size mammals, such as pigs.

Exposure of the astronaut to vacuum would not add to the cooling.

“Explosive depressurization” can produce ebullism (called “blood boiling” in SF circles). This is caused by inert gasses like nitrogen bubbling out of solution. The bubbles block circulation and prevent the effectiveness of pulmonary evaporative cooling. However, EVA astronauts pre-breath O2 to flush nitrogen. This markedly reduces the risk of ebullism. Chimpanzees similarly prepared by pre-breathing O2 “have tolerated exposures to ambient atmospheric pressures of less than 2 mm Hg for up to 210 seconds with a return of apparently normal psychophysiologic function after recompression.” https://ntrs.nasa.gov/citations/19670023576

An EVA astronaut exposed to “explosive depressurization” after pre-breathing O2 would likely survive several minutes of “breathing outer space” a la David Bowman. If emergency therapeutic hypothermia of 30*C was induced by a combination of water dump into the suit and pulmonary evaporative cooling, they would likely survive 8 minutes before re-pressurization rather than 4 minutes without hypothermia.

Once inside the airlock, this induced hypothermia could be treated in a controlled, pre-programmed way with heated oxygen. https://ccforum.biomedcentral.com/articles/10.1186/s13054-020-2839-1 The astronaut would receive warmed 100% O2 at normal atmospheric pressure, using airway and Ambu Bag if necessary. Slow re-warming could be provided using the LCVC. Or the LCVC could be used to maintain hypothermia to treat post-hypoxia cerebral edema. “… hypothermia would apparently be of great value in the treatment of posthypoxic cerebral edema in space … adequate total body cooling might be attained with a water-cooled space suit.” https://ntrs.nasa.gov/citations/19670023576

Answer: No, the capability is not in place to induce therapeutic hypothermia to reduce hypoxic brain damage in a EVA depressurization, or for treating post hypoxic cerebral edema. But maybe it should be considered.“… hypothermia would apparently be of great value in the treatment of posthypoxic cerebral edema in space … adequate total body cooling might be attained with a water-cooled space suit.” https://ntrs.nasa.gov/citations/19670023576

This could potentially slow hypoxic brain damage to allow more favorable prognosis once the astronaut can be re-pressurized.

However, existing LCVC suits do not have the capacity to induce rapid hypothermia. Maybe they could, with minor modification. The Apollo A7L suit could dissipate 2000 BTU/hr. https://en.wikipedia.org/wiki/Liquid_cooling_and_ventilation_garment. This is the equivalent of 500,000 calories, enough to reduce 70kg of astronaut by 7 °C in an hour. Not fast enough.

However, if the 2.7 kg of water in the suit’s LCVC reservoir https://www.hq.nasa.gov/alsj/ALSJ-FlightPLSS.pdf were dumped into the depressurized suit, flash evaporation would provide 1,450,000 calories of evaporative cooling. This is more than enough refrigeration to induce hypothermia of 30 °C, and thereby double the astronaut’s hypoxic survival time. Since the “dump” is both triggered by, and powered by, the vacuum in the depressurized suit, a fail-safe mechanism should be practical.

Basic design research would need to be done on human-size mammals, such as pigs.

Exposure of the astronaut to vacuum would not add to the cooling.

“Explosive depressurization” can produce ebullism (called “blood boiling” in SF circles). This is caused by inert gasses like nitrogen bubbling out of solution. The bubbles block circulation and prevent the effectiveness of pulmonary evaporative cooling. However, EVA astronauts pre-breath O2 to flush nitrogen. This markedly reduces the risk of ebullism. Chimpanzees similarly prepared by pre-breathing O2 “have tolerated exposures to ambient atmospheric pressures of less than 2 mm Hg for up to 210 seconds with a return of apparently normal psychophysiologic function after recompression.” https://ntrs.nasa.gov/citations/19670023576

An EVA astronaut exposed to “explosive depressurization” after pre-breathing O2 would likely survive several minutes of “breathing outer space” a la David Bowman. If emergency therapeutic hypothermia of 30 °C was induced by a combination of water dump into the suit and pulmonary evaporative cooling, they would likely survive 8 minutes before re-pressurization rather than 4 minutes without hypothermia.

Once inside the airlock, this induced hypothermia could be treated in a controlled, pre-programmed way with heated oxygen. https://ccforum.biomedcentral.com/articles/10.1186/s13054-020-2839-1 The astronaut would receive warmed 100% O2 at normal atmospheric pressure, using airway and Ambu Bag if necessary. Slow re-warming could be provided using the LCVC. Or the LCVC could be used to maintain hypothermia to treat post-hypoxia cerebral edema. “… hypothermia would apparently be of great value in the treatment of posthypoxic cerebral edema in space … adequate total body cooling might be attained with a water-cooled space suit.” https://ntrs.nasa.gov/citations/19670023576

Answer: No, the capability is not in place to induce therapeutic hypothermia to reduce hypoxic brain damage in a EVA depressurization, or for treating post hypoxic cerebral edema. But maybe it should be considered.

This could potentially slow hypoxic brain damage to allow more favorable prognosis once the astronaut can be re-pressurized.

However, existing LCVC suits do not have the capacity to induce rapid hypothermia. Maybe they could, with minor modification. The Apollo A7L suit could dissipate 2000 BTU/hr. https://en.wikipedia.org/wiki/Liquid_cooling_and_ventilation_garment. This is the equivalent of 500,000 calories, enough to reduce 70kg of astronaut by 7*C in an hour. Not fast enough.

However, if the 2.7 Kg of water in the suit’s LCVC reservoir https://www.hq.nasa.gov/alsj/ALSJ-FlightPLSS.pdf were dumped into the depressurized suit, flash evaporation would provide 1,450,000 calories of evaporative cooling. This is more than enough refrigeration to induce hypothermia of 30*C, and thereby double the astronaut’s hypoxic survival time. Since the “dump” is both triggered by, and powered by, the vacuum in the depressurized suit, a fail-safe mechanism should be practical.

Basic design research would need to be done on human-size mammals, such as pigs.

Exposure of the astronaut to vacuum would not add to the cooling.

“Explosive depressurization” can produce ebullism (called “blood boiling” in SF circles). This is caused by inert gasses like nitrogen bubbling out of solution. The bubbles block circulation and prevent the effectiveness of pulmonary evaporative cooling. However, EVA astronauts pre-breath O2 to flush nitrogen. This markedly reduces the risk of ebullism. Chimpanzees similarly prepared by pre-breathing O2 “have tolerated exposures to ambient atmospheric pressures of less than 2 mm Hg for up to 210 seconds with a return of apparently normal psychophysiologic function after recompression.” https://ntrs.nasa.gov/citations/19670023576

An EVA astronaut exposed to “explosive depressurization” after pre-breathing O2 would likely survive several minutes of “breathing outer space” a la David Bowman. If emergency therapeutic hypothermia of 30*C was induced by a combination of water dump into the suit and pulmonary evaporative cooling, they would likely survive 8 minutes before re-pressurization.

Once inside the airlock, this induced hypothermia could be treated in a controlled, pre-programmed way with heated oxygen. https://ccforum.biomedcentral.com/articles/10.1186/s13054-020-2839-1 The astronaut would receive warmed 100% O2 at normal atmospheric pressure, using airway and Ambu Bag if necessary. Slow re-warming could be provided using the LCVC. Or the LCVC could be used to maintain hypothermia to treat post-hypoxia cerebral edema. “… hypothermia would apparently be of great value in the treatment of posthypoxic cerebral edema in space … adequate total body cooling might be attained with a water-cooled space suit.” https://ntrs.nasa.gov/citations/19670023576

Answer: No, the capability is not in place to induce therapeutic hypothermia to reduce hypoxic brain damage in a EVA depressurization, or for treating post hypoxic cerebral edema. But maybe it should be considered.“… hypothermia would apparently be of great value in the treatment of posthypoxic cerebral edema in space … adequate total body cooling might be attained with a water-cooled space suit.” https://ntrs.nasa.gov/citations/19670023576

This could potentially slow hypoxic brain damage to allow more favorable prognosis once the astronaut can be re-pressurized.

However, existing LCVC suits do not have the capacity to induce rapid hypothermia. Maybe they could, with minor modification. The Apollo A7L suit could dissipate 2000 BTU/hr. https://en.wikipedia.org/wiki/Liquid_cooling_and_ventilation_garment. This is the equivalent of 500,000 calories, enough to reduce 70kg of astronaut by 7*C in an hour. Not fast enough.

However, if the 2.7 Kg of water in the suit’s LCVC reservoir https://www.hq.nasa.gov/alsj/ALSJ-FlightPLSS.pdf were dumped into the depressurized suit, flash evaporation would provide 1,450,000 calories of evaporative cooling. This is more than enough refrigeration to induce hypothermia of 30*C, and thereby double the astronaut’s hypoxic survival time. Since the “dump” is both triggered by, and powered by, the vacuum in the depressurized suit, a fail-safe mechanism should be practical.

Basic design research would need to be done on human-size mammals, such as pigs.

Exposure of the astronaut to vacuum would not add to the cooling.

“Explosive depressurization” can produce ebullism (called “blood boiling” in SF circles). This is caused by inert gasses like nitrogen bubbling out of solution. The bubbles block circulation and prevent the effectiveness of pulmonary evaporative cooling. However, EVA astronauts pre-breath O2 to flush nitrogen. This markedly reduces the risk of ebullism. Chimpanzees similarly prepared by pre-breathing O2 “have tolerated exposures to ambient atmospheric pressures of less than 2 mm Hg for up to 210 seconds with a return of apparently normal psychophysiologic function after recompression.” https://ntrs.nasa.gov/citations/19670023576

An EVA astronaut exposed to “explosive depressurization” after pre-breathing O2 would likely survive several minutes of “breathing outer space” a la David Bowman. If emergency therapeutic hypothermia of 30*C was induced by a combination of water dump into the suit and pulmonary evaporative cooling, they would likely survive 8 minutes before re-pressurization rather than 4 minutes without hypothermia.

Once inside the airlock, this induced hypothermia could be treated in a controlled, pre-programmed way with heated oxygen. https://ccforum.biomedcentral.com/articles/10.1186/s13054-020-2839-1 The astronaut would receive warmed 100% O2 at normal atmospheric pressure, using airway and Ambu Bag if necessary. Slow re-warming could be provided using the LCVC. Or the LCVC could be used to maintain hypothermia to treat post-hypoxia cerebral edema. “… hypothermia would apparently be of great value in the treatment of posthypoxic cerebral edema in space … adequate total body cooling might be attained with a water-cooled space suit.” https://ntrs.nasa.gov/citations/19670023576