FREQUENTLY ASKED QUESTIONS (FAQ)

 TORPOR INDUCING TRANSFER HABITAT FOR HUMAN STASIS TO MARS

 

Questions on the Medical Aspects

Torpor (or Hibernation) is a state of inactivity characterized by low body temperature, slow breathing and heart rate, and low metabolic rate. Many animals in nature hibernate to conserve energy during periods when sufficient food supplies are unavailable. To achieve this, hibernators will decrease their metabolic rate, which then results in a decreased body temperature. Hibernation may last several days, weeks, or months depending on the species, ambient temperature, time of year, and individual’s body condition.

Doctors in patient care for extreme trauma are currently applying this idea. Medically induced Torpor (called Therapeutic Hypothermia) is a medical treatment that lowers a patient’s body temperature in order to help reduce the risk of the injury to tissue during a period of poor blood flow. Examples include patients that suffer from cardiac arrest, stroke, trauma and brain injuries, as well as infants that are premature or had a complicated delivery. Lowering the patient’s temperature by even a couple of degrees (to 34oC or 93oF) can produce the same effects that are seen in animals, including slowed breathing and heart rate, and a decreased metabolic rate. This reduced metabolic rate means a lower need for oxygen by cells in the human body, protecting them from damage during the medical emergencies listed above.

Crew members that are in a Torpor state will get their nutrition through a process called Total Parenteral Nutrition (TPN). With TPN the crew member will obtain all nutrients (such as glucose, amino acids, lipids, added vitamins and dietary minerals) through an intravenous (IV) line, bypassing the usual process of eating and digestion. TPN is a well-known and often used medical process for the long-term care of preterm infants and adults that are suffering from medical conditions that do not allow them eat.

The physical sensation of hunger is related to contractions of the stomach muscles. These contractions, sometimes called hunger pangs, are believed to be triggered by high concentrations of the hormones (Ghrelin is the most common) that is released if a person’s blood sugar levels get low.

Yes! Astronauts that are in Torpor are in a deep sleep similar to that of bears and other hibernating animals. Because their body is at a decreased temperature they will experience a decrease in metabolism. This will result in a decrease in their respiratory rate, heart rate, and blood pressure. However, crew members in Torpor will continue to have normal physiologic processes.

Torpor is achieved by decreasing a crew member’s core temperature to approximately 34oC (93oF). There are several techniques that can be used to accomplish this. Some are invasive, involving injecting a cooled saline solution into the femoral vein, while others are non-invasive, such as circulating cold water through a blanket or body pads. Our preferred solution is called Trans Nasal Evaporative Cooling. With this approach, a small plastic tube is inserted into a crew member’s nasal cavity. This is used to deliver a spray of coolant mist that evaporates directly underneath the brain and base of the skull. As blood passes through the cooling area, it reduces the temperature throughout the rest of the body. The current terrestrial variant of this system is called RhinoChill® by BeneChill, Inc.

Administering nutrition and hydration via Total Parenteral Nutrition (TPN) requires use of an intravenous (IV) line and no additional equipment.

Crewmembers will also have monitoring equipment similar to those seen in a normal hospital setting to monitor their vital signs while in the Torpor state.

There is no direct evidence on what effect Torpor will have on aging. This is primarily due to the fact that current uses for Torpor in the medical community are limited to several days or weeks. However, there is evidence from multiple animal studies that show that hibernating animals do live longer than non-hibernating animals. It is physiologically possible that since torpor decreases a crewmember’s metabolism it would cause cells to age and die at a slower rate, slowing the “aging” process.

Yes, human senses continue to work while we are sleeping. Similarly crewmembers in a Torpor state will continue to be able to feel, hear, and see bright lights in their sleep state. However, typically humans require a very small amount of a mild sedative to suppress the body’s natural shiver response that occurs while undergoing Torpor. This sedative would prevent normal sensory stimulation from affecting the astronauts while in hibernation.

Currently there is no data available on the effects of long-term Torpor on mental, physical or cognitive function. Therapeutic Hypothermia (TH) is only used by the medical community on critically injured or ill patients. These patients have baseline mental, physical and/or cognitive function impairment due to these injuries, making isolating the long-term effects of Torpor hard to predict.

However, hibernating animals like the black bear can be aroused and fully functional in a very short period of time to protect themselves while in torpor. This would suggest it is plausible that humans may be able to awaken from prolonged torpor with minimal affect to mental, physical or cognitive function. Researchers around the world are actively studying this process in animals to understand exactly how and why it works. This is also something we can conduct human trials for here on Earth before attempting it in a space environment.

Skylab and Russian Space data shows us that astronauts lose approximately 8% bone mineral density after 84 days in space. This increases to 19% by 140 days. Theoretically, an astronaut could lose up to 50% or more of their bone mineral density over a 3-year space mission.

Significant atrophy of skeletal muscle starts after only 5 days in space, and there is no idea if and when a plateau of atrophy would be reached. Most of these changes appear to be due to deconditioning and not any particular microgravity pathology. However, cycling and treadmill activity do not appear to affect muscle density loss but do prevent biophysical changes (gait changes, foot drop) that worsen density loss and recovery.

There are some changes in the cardiovascular system (decreased fluid volume, decrease in stroke volume and cardiac output by about 15%) with prolonged space travel. However, there are no noted changes in heart rate or function so these changes do not appear to be a health risk at this time.

NASA has extensively worked to identify therapeutic and preventive measures to combat these issues.

Many studies have been performed on Trans Nasal Evaporative Cooling systems. Studies have shown that for the methods used currently it does not occlude the nostrils and no erosion of the nasal mucosa was seen, although care and lubrication was required when inserting the nasal catheters to avoid causing nosebleeds. There was no evidence of sinusitis, tympanic membrane injury or olfactory dysfunction. We would also note that the flow rate of the gas is very low and that it is not always being released. It is only used when the body temperature starts to rise and exceed the target temperature range.

Many reseachers have noted that the procedure may cause an oppressive feeling due to the high volume of circulating air and that it is only suitable in sedated patients. With high flow systems the large amount of dry air was noted to cause stinging and dryness of the nasal mucosa during initiation, but this was temporary and counteracted by either moisturized air or lubricant when placing the tubes.

Corneal stenosis is a disorder of the eyes characterized by damage or erosion to the outermost layer of cells of the eye. The condition is excruciatingly painful because the loss of these cells results in the exposure of sensitive corneal nerves. Corneal stenosis can occur in medical patients that are in a coma or other prolonged sleep state as the cornea tends to dry out the longer the eyelids are closed. Prevention of this condition includes ensuring that the air is humidified rather than dry, maintaining general hydration levels with adequate fluid intake, applying long-lasting eye ointments before starting the sleep cycle, and applying artificial tear drops under the inner corner of the eyelids before opening eyes upon waking.

Pressure ulcers (also known as decubitus ulcers or bedsores) are injuries to the skin or underlying tissue. They occur due to pressure applied to the tissue resulting in partial or complete blood flow blockage of the blood supply to soft tissue. Pressure ulcers most commonly develop in persons who are not able to move on their own. Fortunately these injuries are easily preventable and treatable if detected early. Primary prevention is to redistribute pressure by turning the patient regularly. In addition to turning and re-positioning, eating a balanced diet with adequate protein and keeping the skin free from exposure to contaminants is also helpful.

In a microgravity environment crewmembers would have minimal pressure applied to the skin and soft tissue, which would greatly reduce the incidence and severity of pressure ulcers during a torpor state.

As noted above, Therapeutic Hypothermia and Total Parenteral Nutrition are medical procedures that are used in every major medical center in the United States. They have been well studied in both animal and human investigative trials. Current human studies have shown the safety and medical benefit of Torpor for as long as 14 days straight and as many as 5 repeat cycles. Prolonged Therapeutic Hypothermia resulting in Torpor greater than that has not been studied at this point and would need to be investigated further.

Microgravity-Induced Visual Impairment/Intracranial Pressure (VIIP) is of recent concern at NASA regarding long-duration space missions. Although its exact cause is not known at this time, it is suspected that the low gravity space environment causes a fluid shift to the brain. This causes an increase in the crewmember’s intracranial pressure (ICP) resulting in optic disc edema and globe eye flattening that can cause mild but persistent changes vision. NASA is currently looking at how to address this medical concern.

Medically therapeutic hypothermia has remained a controversial issue in the debate concerning the management of elevated intracranial hypertension. It is not currently recommended as a standard treatment for increased intracranial pressure in any clinical setting. However, recent studies suggest that hypothermia can lower ICP and may improve patient outcomes. Hypothermia also appeared to be effective in lowering ICP after other therapies have failed.

Patients that undergo Therapeutic Hypothermia do not all respond in the same physiologic manner. Some patients have a very strong shiver response that requires multiple large doses of sedation medications to control while others have only mild or no shivering response at all. Similarly, the effects on patient heart rate, blood pressure, coagulation factors, white blood cells and blood sugar are all widely variable. This would indicate that some patients are just better suited to handle the physiologic effects of TH than others. In addition, there is some evidence from patients that have undergone repeat cycles of Therapeutic Hypothermia that the body becomes accustomed to the physical changes that occur, resulting in decreased physiologic complications.

Because of this it would be feasible to place all available astronauts from the mission pool under short test cycles of TH and identify which ones are least likely to have complications. In addition, crew members that were mission critical or had moderate to mild complications may be able to be conditioned for the Torpor state by undergoing short repeat cycles.

Questions on the Medical Aspects

Torpor (or Hibernation) is a state of inactivity characterized by low body temperature, slow breathing and heart rate, and low metabolic rate. Many animals in nature hibernate to conserve energy during periods when sufficient food supplies are unavailable. To achieve this, hibernators will decrease their metabolic rate, which then results in a decreased body temperature. Hibernation may last several days, weeks, or months depending on the species, ambient temperature, time of year, and individual’s body condition.

Doctors in patient care for extreme trauma are currently applying this idea. Medically induced Torpor (called Therapeutic Hypothermia) is a medical treatment that lowers a patient’s body temperature in order to help reduce the risk of the injury to tissue during a period of poor blood flow. Examples include patients that suffer from cardiac arrest, stroke, trauma and brain injuries, as well as infants that are premature or had a complicated delivery. Lowering the patient’s temperature by even a couple of degrees (to 34oC or 93oF) can produce the same effects that are seen in animals, including slowed breathing and heart rate, and a decreased metabolic rate. This reduced metabolic rate means a lower need for oxygen by cells in the human body, protecting them from damage during the medical emergencies listed above.

Crew members that are in a Torpor state will get their nutrition through a process called Total Parenteral Nutrition (TPN). With TPN the crew member will obtain all nutrients (such as glucose, amino acids, lipids, added vitamins and dietary minerals) through an intravenous (IV) line, bypassing the usual process of eating and digestion. TPN is a well-known and often used medical process for the long-term care of preterm infants and adults that are suffering from medical conditions that do not allow them eat.

The physical sensation of hunger is related to contractions of the stomach muscles. These contractions, sometimes called hunger pangs, are believed to be triggered by high concentrations of the hormones (Ghrelin is the most common) that is released if a person’s blood sugar levels get low.

Yes! Astronauts that are in Torpor are in a deep sleep similar to that of bears and other hibernating animals. Because their body is at a decreased temperature they will experience a decrease in metabolism. This will result in a decrease in their respiratory rate, heart rate, and blood pressure. However, crew members in Torpor will continue to have normal physiologic processes.

Torpor is achieved by decreasing a crew member’s core temperature to approximately 34oC (93oF). There are several techniques that can be used to accomplish this. Some are invasive, involving injecting a cooled saline solution into the femoral vein, while others are non-invasive, such as circulating cold water through a blanket or body pads. Our preferred solution is called Trans Nasal Evaporative Cooling. With this approach, a small plastic tube is inserted into a crew member’s nasal cavity. This is used to deliver a spray of coolant mist that evaporates directly underneath the brain and base of the skull. As blood passes through the cooling area, it reduces the temperature throughout the rest of the body. The current terrestrial variant of this system is called RhinoChill® by BeneChill, Inc.

Administering nutrition and hydration via Total Parenteral Nutrition (TPN) requires use of an intravenous (IV) line and no additional equipment.

Crewmembers will also have monitoring equipment similar to those seen in a normal hospital setting to monitor their vital signs while in the Torpor state.

There is no direct evidence on what effect Torpor will have on aging. This is primarily due to the fact that current uses for Torpor in the medical community are limited to several days or weeks. However, there is evidence from multiple animal studies that show that hibernating animals do live longer than non-hibernating animals. It is physiologically possible that since torpor decreases a crewmember’s metabolism it would cause cells to age and die at a slower rate, slowing the “aging” process.

Yes, human senses continue to work while we are sleeping. Similarly crewmembers in a Torpor state will continue to be able to feel, hear, and see bright lights in their sleep state. However, typically humans require a very small amount of a mild sedative to suppress the body’s natural shiver response that occurs while undergoing Torpor. This sedative would prevent normal sensory stimulation from affecting the astronauts while in hibernation.

Currently there is no data available on the effects of long-term Torpor on mental, physical or cognitive function. Therapeutic Hypothermia (TH) is only used by the medical community on critically injured or ill patients. These patients have baseline mental, physical and/or cognitive function impairment due to these injuries, making isolating the long-term effects of Torpor hard to predict.

However, hibernating animals like the black bear can be aroused and fully functional in a very short period of time to protect themselves while in torpor. This would suggest it is plausible that humans may be able to awaken from prolonged torpor with minimal affect to mental, physical or cognitive function. Researchers around the world are actively studying this process in animals to understand exactly how and why it works. This is also something we can conduct human trials for here on Earth before attempting it in a space environment.

Skylab and Russian Space data shows us that astronauts lose approximately 8% bone mineral density after 84 days in space. This increases to 19% by 140 days. Theoretically, an astronaut could lose up to 50% or more of their bone mineral density over a 3-year space mission.

Significant atrophy of skeletal muscle starts after only 5 days in space, and there is no idea if and when a plateau of atrophy would be reached. Most of these changes appear to be due to deconditioning and not any particular microgravity pathology. However, cycling and treadmill activity do not appear to affect muscle density loss but do prevent biophysical changes (gait changes, foot drop) that worsen density loss and recovery.

There are some changes in the cardiovascular system (decreased fluid volume, decrease in stroke volume and cardiac output by about 15%) with prolonged space travel. However, there are no noted changes in heart rate or function so these changes do not appear to be a health risk at this time.

NASA has extensively worked to identify therapeutic and preventive measures to combat these issues.

Many studies have been performed on Trans Nasal Evaporative Cooling systems. Studies have shown that for the methods used currently it does not occlude the nostrils and no erosion of the nasal mucosa was seen, although care and lubrication was required when inserting the nasal catheters to avoid causing nosebleeds. There was no evidence of sinusitis, tympanic membrane injury or olfactory dysfunction. We would also note that the flow rate of the gas is very low and that it is not always being released. It is only used when the body temperature starts to rise and exceed the target temperature range.

Many reseachers have noted that the procedure may cause an oppressive feeling due to the high volume of circulating air and that it is only suitable in sedated patients. With high flow systems the large amount of dry air was noted to cause stinging and dryness of the nasal mucosa during initiation, but this was temporary and counteracted by either moisturized air or lubricant when placing the tubes.

Corneal stenosis is a disorder of the eyes characterized by damage or erosion to the outermost layer of cells of the eye. The condition is excruciatingly painful because the loss of these cells results in the exposure of sensitive corneal nerves. Corneal stenosis can occur in medical patients that are in a coma or other prolonged sleep state as the cornea tends to dry out the longer the eyelids are closed. Prevention of this condition includes ensuring that the air is humidified rather than dry, maintaining general hydration levels with adequate fluid intake, applying long-lasting eye ointments before starting the sleep cycle, and applying artificial tear drops under the inner corner of the eyelids before opening eyes upon waking.

Pressure ulcers (also known as decubitus ulcers or bedsores) are injuries to the skin or underlying tissue. They occur due to pressure applied to the tissue resulting in partial or complete blood flow blockage of the blood supply to soft tissue. Pressure ulcers most commonly develop in persons who are not able to move on their own. Fortunately these injuries are easily preventable and treatable if detected early. Primary prevention is to redistribute pressure by turning the patient regularly. In addition to turning and re-positioning, eating a balanced diet with adequate protein and keeping the skin free from exposure to contaminants is also helpful.

In a microgravity environment crewmembers would have minimal pressure applied to the skin and soft tissue, which would greatly reduce the incidence and severity of pressure ulcers during a torpor state.

As noted above, Therapeutic Hypothermia and Total Parenteral Nutrition are medical procedures that are used in every major medical center in the United States. They have been well studied in both animal and human investigative trials. Current human studies have shown the safety and medical benefit of Torpor for as long as 14 days straight and as many as 5 repeat cycles. Prolonged Therapeutic Hypothermia resulting in Torpor greater than that has not been studied at this point and would need to be investigated further.

Microgravity-Induced Visual Impairment/Intracranial Pressure (VIIP) is of recent concern at NASA regarding long-duration space missions. Although its exact cause is not known at this time, it is suspected that the low gravity space environment causes a fluid shift to the brain. This causes an increase in the crewmember’s intracranial pressure (ICP) resulting in optic disc edema and globe eye flattening that can cause mild but persistent changes vision. NASA is currently looking at how to address this medical concern.

Medically therapeutic hypothermia has remained a controversial issue in the debate concerning the management of elevated intracranial hypertension. It is not currently recommended as a standard treatment for increased intracranial pressure in any clinical setting. However, recent studies suggest that hypothermia can lower ICP and may improve patient outcomes. Hypothermia also appeared to be effective in lowering ICP after other therapies have failed.

Patients that undergo Therapeutic Hypothermia do not all respond in the same physiologic manner. Some patients have a very strong shiver response that requires multiple large doses of sedation medications to control while others have only mild or no shivering response at all. Similarly, the effects on patient heart rate, blood pressure, coagulation factors, white blood cells and blood sugar are all widely variable. This would indicate that some patients are just better suited to handle the physiologic effects of TH than others. In addition, there is some evidence from patients that have undergone repeat cycles of Therapeutic Hypothermia that the body becomes accustomed to the physical changes that occur, resulting in decreased physiologic complications.

Because of this it would be feasible to place all available astronauts from the mission pool under short test cycles of TH and identify which ones are least likely to have complications. In addition, crew members that were mission critical or had moderate to mild complications may be able to be conditioned for the Torpor state by undergoing short repeat cycles.

Questions on the Medical Aspects

Torpor (or Hibernation) is a state of inactivity characterized by low body temperature, slow breathing and heart rate, and low metabolic rate. Many animals in nature hibernate to conserve energy during periods when sufficient food supplies are unavailable. To achieve this, hibernators will decrease their metabolic rate, which then results in a decreased body temperature. Hibernation may last several days, weeks, or months depending on the species, ambient temperature, time of year, and individual’s body condition.

Doctors in patient care for extreme trauma are currently applying this idea. Medically induced Torpor (called Therapeutic Hypothermia) is a medical treatment that lowers a patient’s body temperature in order to help reduce the risk of the injury to tissue during a period of poor blood flow. Examples include patients that suffer from cardiac arrest, stroke, trauma and brain injuries, as well as infants that are premature or had a complicated delivery. Lowering the patient’s temperature by even a couple of degrees (to 34oC or 93oF) can produce the same effects that are seen in animals, including slowed breathing and heart rate, and a decreased metabolic rate. This reduced metabolic rate means a lower need for oxygen by cells in the human body, protecting them from damage during the medical emergencies listed above.

Crew members that are in a Torpor state will get their nutrition through a process called Total Parenteral Nutrition (TPN). With TPN the crew member will obtain all nutrients (such as glucose, amino acids, lipids, added vitamins and dietary minerals) through an intravenous (IV) line, bypassing the usual process of eating and digestion. TPN is a well-known and often used medical process for the long-term care of preterm infants and adults that are suffering from medical conditions that do not allow them eat.

The physical sensation of hunger is related to contractions of the stomach muscles. These contractions, sometimes called hunger pangs, are believed to be triggered by high concentrations of the hormones (Ghrelin is the most common) that is released if a person’s blood sugar levels get low.

Yes! Astronauts that are in Torpor are in a deep sleep similar to that of bears and other hibernating animals. Because their body is at a decreased temperature they will experience a decrease in metabolism. This will result in a decrease in their respiratory rate, heart rate, and blood pressure. However, crew members in Torpor will continue to have normal physiologic processes.

Torpor is achieved by decreasing a crew member’s core temperature to approximately 34oC (93oF). There are several techniques that can be used to accomplish this. Some are invasive, involving injecting a cooled saline solution into the femoral vein, while others are non-invasive, such as circulating cold water through a blanket or body pads. Our preferred solution is called Trans Nasal Evaporative Cooling. With this approach, a small plastic tube is inserted into a crew member’s nasal cavity. This is used to deliver a spray of coolant mist that evaporates directly underneath the brain and base of the skull. As blood passes through the cooling area, it reduces the temperature throughout the rest of the body. The current terrestrial variant of this system is called RhinoChill® by BeneChill, Inc.

Administering nutrition and hydration via Total Parenteral Nutrition (TPN) requires use of an intravenous (IV) line and no additional equipment.

Crewmembers will also have monitoring equipment similar to those seen in a normal hospital setting to monitor their vital signs while in the Torpor state.

There is no direct evidence on what effect Torpor will have on aging. This is primarily due to the fact that current uses for Torpor in the medical community are limited to several days or weeks. However, there is evidence from multiple animal studies that show that hibernating animals do live longer than non-hibernating animals. It is physiologically possible that since torpor decreases a crewmember’s metabolism it would cause cells to age and die at a slower rate, slowing the “aging” process.

Yes, human senses continue to work while we are sleeping. Similarly crewmembers in a Torpor state will continue to be able to feel, hear, and see bright lights in their sleep state. However, typically humans require a very small amount of a mild sedative to suppress the body’s natural shiver response that occurs while undergoing Torpor. This sedative would prevent normal sensory stimulation from affecting the astronauts while in hibernation.

Currently there is no data available on the effects of long-term Torpor on mental, physical or cognitive function. Therapeutic Hypothermia (TH) is only used by the medical community on critically injured or ill patients. These patients have baseline mental, physical and/or cognitive function impairment due to these injuries, making isolating the long-term effects of Torpor hard to predict.

However, hibernating animals like the black bear can be aroused and fully functional in a very short period of time to protect themselves while in torpor. This would suggest it is plausible that humans may be able to awaken from prolonged torpor with minimal affect to mental, physical or cognitive function. Researchers around the world are actively studying this process in animals to understand exactly how and why it works. This is also something we can conduct human trials for here on Earth before attempting it in a space environment.

Skylab and Russian Space data shows us that astronauts lose approximately 8% bone mineral density after 84 days in space. This increases to 19% by 140 days. Theoretically, an astronaut could lose up to 50% or more of their bone mineral density over a 3-year space mission.

Significant atrophy of skeletal muscle starts after only 5 days in space, and there is no idea if and when a plateau of atrophy would be reached. Most of these changes appear to be due to deconditioning and not any particular microgravity pathology. However, cycling and treadmill activity do not appear to affect muscle density loss but do prevent biophysical changes (gait changes, foot drop) that worsen density loss and recovery.

There are some changes in the cardiovascular system (decreased fluid volume, decrease in stroke volume and cardiac output by about 15%) with prolonged space travel. However, there are no noted changes in heart rate or function so these changes do not appear to be a health risk at this time.

NASA has extensively worked to identify therapeutic and preventive measures to combat these issues.

Many studies have been performed on Trans Nasal Evaporative Cooling systems. Studies have shown that for the methods used currently it does not occlude the nostrils and no erosion of the nasal mucosa was seen, although care and lubrication was required when inserting the nasal catheters to avoid causing nosebleeds. There was no evidence of sinusitis, tympanic membrane injury or olfactory dysfunction. We would also note that the flow rate of the gas is very low and that it is not always being released. It is only used when the body temperature starts to rise and exceed the target temperature range.

Many reseachers have noted that the procedure may cause an oppressive feeling due to the high volume of circulating air and that it is only suitable in sedated patients. With high flow systems the large amount of dry air was noted to cause stinging and dryness of the nasal mucosa during initiation, but this was temporary and counteracted by either moisturized air or lubricant when placing the tubes.

Corneal stenosis is a disorder of the eyes characterized by damage or erosion to the outermost layer of cells of the eye. The condition is excruciatingly painful because the loss of these cells results in the exposure of sensitive corneal nerves. Corneal stenosis can occur in medical patients that are in a coma or other prolonged sleep state as the cornea tends to dry out the longer the eyelids are closed. Prevention of this condition includes ensuring that the air is humidified rather than dry, maintaining general hydration levels with adequate fluid intake, applying long-lasting eye ointments before starting the sleep cycle, and applying artificial tear drops under the inner corner of the eyelids before opening eyes upon waking.

Pressure ulcers (also known as decubitus ulcers or bedsores) are injuries to the skin or underlying tissue. They occur due to pressure applied to the tissue resulting in partial or complete blood flow blockage of the blood supply to soft tissue. Pressure ulcers most commonly develop in persons who are not able to move on their own. Fortunately these injuries are easily preventable and treatable if detected early. Primary prevention is to redistribute pressure by turning the patient regularly. In addition to turning and re-positioning, eating a balanced diet with adequate protein and keeping the skin free from exposure to contaminants is also helpful.

In a microgravity environment crewmembers would have minimal pressure applied to the skin and soft tissue, which would greatly reduce the incidence and severity of pressure ulcers during a torpor state.

As noted above, Therapeutic Hypothermia and Total Parenteral Nutrition are medical procedures that are used in every major medical center in the United States. They have been well studied in both animal and human investigative trials. Current human studies have shown the safety and medical benefit of Torpor for as long as 14 days straight and as many as 5 repeat cycles. Prolonged Therapeutic Hypothermia resulting in Torpor greater than that has not been studied at this point and would need to be investigated further.

Microgravity-Induced Visual Impairment/Intracranial Pressure (VIIP) is of recent concern at NASA regarding long-duration space missions. Although its exact cause is not known at this time, it is suspected that the low gravity space environment causes a fluid shift to the brain. This causes an increase in the crewmember’s intracranial pressure (ICP) resulting in optic disc edema and globe eye flattening that can cause mild but persistent changes vision. NASA is currently looking at how to address this medical concern.

Medically therapeutic hypothermia has remained a controversial issue in the debate concerning the management of elevated intracranial hypertension. It is not currently recommended as a standard treatment for increased intracranial pressure in any clinical setting. However, recent studies suggest that hypothermia can lower ICP and may improve patient outcomes. Hypothermia also appeared to be effective in lowering ICP after other therapies have failed.

Patients that undergo Therapeutic Hypothermia do not all respond in the same physiologic manner. Some patients have a very strong shiver response that requires multiple large doses of sedation medications to control while others have only mild or no shivering response at all. Similarly, the effects on patient heart rate, blood pressure, coagulation factors, white blood cells and blood sugar are all widely variable. This would indicate that some patients are just better suited to handle the physiologic effects of TH than others. In addition, there is some evidence from patients that have undergone repeat cycles of Therapeutic Hypothermia that the body becomes accustomed to the physical changes that occur, resulting in decreased physiologic complications.

Because of this it would be feasible to place all available astronauts from the mission pool under short test cycles of TH and identify which ones are least likely to have complications. In addition, crew members that were mission critical or had moderate to mild complications may be able to be conditioned for the Torpor state by undergoing short repeat cycles.

Questions on the Medical Aspects

Torpor (or Hibernation) is a state of inactivity characterized by low body temperature, slow breathing and heart rate, and low metabolic rate. Many animals in nature hibernate to conserve energy during periods when sufficient food supplies are unavailable. To achieve this, hibernators will decrease their metabolic rate, which then results in a decreased body temperature. Hibernation may last several days, weeks, or months depending on the species, ambient temperature, time of year, and individual’s body condition.

Doctors in patient care for extreme trauma are currently applying this idea. Medically induced Torpor (called Therapeutic Hypothermia) is a medical treatment that lowers a patient’s body temperature in order to help reduce the risk of the injury to tissue during a period of poor blood flow. Examples include patients that suffer from cardiac arrest, stroke, trauma and brain injuries, as well as infants that are premature or had a complicated delivery. Lowering the patient’s temperature by even a couple of degrees (to 34oC or 93oF) can produce the same effects that are seen in animals, including slowed breathing and heart rate, and a decreased metabolic rate. This reduced metabolic rate means a lower need for oxygen by cells in the human body, protecting them from damage during the medical emergencies listed above.

Crew members that are in a Torpor state will get their nutrition through a process called Total Parenteral Nutrition (TPN). With TPN the crew member will obtain all nutrients (such as glucose, amino acids, lipids, added vitamins and dietary minerals) through an intravenous (IV) line, bypassing the usual process of eating and digestion. TPN is a well-known and often used medical process for the long-term care of preterm infants and adults that are suffering from medical conditions that do not allow them eat.

The physical sensation of hunger is related to contractions of the stomach muscles. These contractions, sometimes called hunger pangs, are believed to be triggered by high concentrations of the hormones (Ghrelin is the most common) that is released if a person’s blood sugar levels get low.

Yes! Astronauts that are in Torpor are in a deep sleep similar to that of bears and other hibernating animals. Because their body is at a decreased temperature they will experience a decrease in metabolism. This will result in a decrease in their respiratory rate, heart rate, and blood pressure. However, crew members in Torpor will continue to have normal physiologic processes.

Torpor is achieved by decreasing a crew member’s core temperature to approximately 34oC (93oF). There are several techniques that can be used to accomplish this. Some are invasive, involving injecting a cooled saline solution into the femoral vein, while others are non-invasive, such as circulating cold water through a blanket or body pads. Our preferred solution is called Trans Nasal Evaporative Cooling. With this approach, a small plastic tube is inserted into a crew member’s nasal cavity. This is used to deliver a spray of coolant mist that evaporates directly underneath the brain and base of the skull. As blood passes through the cooling area, it reduces the temperature throughout the rest of the body. The current terrestrial variant of this system is called RhinoChill® by BeneChill, Inc.

Administering nutrition and hydration via Total Parenteral Nutrition (TPN) requires use of an intravenous (IV) line and no additional equipment.

Crewmembers will also have monitoring equipment similar to those seen in a normal hospital setting to monitor their vital signs while in the Torpor state.

There is no direct evidence on what effect Torpor will have on aging. This is primarily due to the fact that current uses for Torpor in the medical community are limited to several days or weeks. However, there is evidence from multiple animal studies that show that hibernating animals do live longer than non-hibernating animals. It is physiologically possible that since torpor decreases a crewmember’s metabolism it would cause cells to age and die at a slower rate, slowing the “aging” process.

Yes, human senses continue to work while we are sleeping. Similarly crewmembers in a Torpor state will continue to be able to feel, hear, and see bright lights in their sleep state. However, typically humans require a very small amount of a mild sedative to suppress the body’s natural shiver response that occurs while undergoing Torpor. This sedative would prevent normal sensory stimulation from affecting the astronauts while in hibernation.

Currently there is no data available on the effects of long-term Torpor on mental, physical or cognitive function. Therapeutic Hypothermia (TH) is only used by the medical community on critically injured or ill patients. These patients have baseline mental, physical and/or cognitive function impairment due to these injuries, making isolating the long-term effects of Torpor hard to predict.

However, hibernating animals like the black bear can be aroused and fully functional in a very short period of time to protect themselves while in torpor. This would suggest it is plausible that humans may be able to awaken from prolonged torpor with minimal affect to mental, physical or cognitive function. Researchers around the world are actively studying this process in animals to understand exactly how and why it works. This is also something we can conduct human trials for here on Earth before attempting it in a space environment.

Skylab and Russian Space data shows us that astronauts lose approximately 8% bone mineral density after 84 days in space. This increases to 19% by 140 days. Theoretically, an astronaut could lose up to 50% or more of their bone mineral density over a 3-year space mission.

Significant atrophy of skeletal muscle starts after only 5 days in space, and there is no idea if and when a plateau of atrophy would be reached. Most of these changes appear to be due to deconditioning and not any particular microgravity pathology. However, cycling and treadmill activity do not appear to affect muscle density loss but do prevent biophysical changes (gait changes, foot drop) that worsen density loss and recovery.

There are some changes in the cardiovascular system (decreased fluid volume, decrease in stroke volume and cardiac output by about 15%) with prolonged space travel. However, there are no noted changes in heart rate or function so these changes do not appear to be a health risk at this time.

NASA has extensively worked to identify therapeutic and preventive measures to combat these issues.

Many studies have been performed on Trans Nasal Evaporative Cooling systems. Studies have shown that for the methods used currently it does not occlude the nostrils and no erosion of the nasal mucosa was seen, although care and lubrication was required when inserting the nasal catheters to avoid causing nosebleeds. There was no evidence of sinusitis, tympanic membrane injury or olfactory dysfunction. We would also note that the flow rate of the gas is very low and that it is not always being released. It is only used when the body temperature starts to rise and exceed the target temperature range.

Many reseachers have noted that the procedure may cause an oppressive feeling due to the high volume of circulating air and that it is only suitable in sedated patients. With high flow systems the large amount of dry air was noted to cause stinging and dryness of the nasal mucosa during initiation, but this was temporary and counteracted by either moisturized air or lubricant when placing the tubes.

Corneal stenosis is a disorder of the eyes characterized by damage or erosion to the outermost layer of cells of the eye. The condition is excruciatingly painful because the loss of these cells results in the exposure of sensitive corneal nerves. Corneal stenosis can occur in medical patients that are in a coma or other prolonged sleep state as the cornea tends to dry out the longer the eyelids are closed. Prevention of this condition includes ensuring that the air is humidified rather than dry, maintaining general hydration levels with adequate fluid intake, applying long-lasting eye ointments before starting the sleep cycle, and applying artificial tear drops under the inner corner of the eyelids before opening eyes upon waking.

Pressure ulcers (also known as decubitus ulcers or bedsores) are injuries to the skin or underlying tissue. They occur due to pressure applied to the tissue resulting in partial or complete blood flow blockage of the blood supply to soft tissue. Pressure ulcers most commonly develop in persons who are not able to move on their own. Fortunately these injuries are easily preventable and treatable if detected early. Primary prevention is to redistribute pressure by turning the patient regularly. In addition to turning and re-positioning, eating a balanced diet with adequate protein and keeping the skin free from exposure to contaminants is also helpful.

In a microgravity environment crewmembers would have minimal pressure applied to the skin and soft tissue, which would greatly reduce the incidence and severity of pressure ulcers during a torpor state.

As noted above, Therapeutic Hypothermia and Total Parenteral Nutrition are medical procedures that are used in every major medical center in the United States. They have been well studied in both animal and human investigative trials. Current human studies have shown the safety and medical benefit of Torpor for as long as 14 days straight and as many as 5 repeat cycles. Prolonged Therapeutic Hypothermia resulting in Torpor greater than that has not been studied at this point and would need to be investigated further.

Microgravity-Induced Visual Impairment/Intracranial Pressure (VIIP) is of recent concern at NASA regarding long-duration space missions. Although its exact cause is not known at this time, it is suspected that the low gravity space environment causes a fluid shift to the brain. This causes an increase in the crewmember’s intracranial pressure (ICP) resulting in optic disc edema and globe eye flattening that can cause mild but persistent changes vision. NASA is currently looking at how to address this medical concern.

Medically therapeutic hypothermia has remained a controversial issue in the debate concerning the management of elevated intracranial hypertension. It is not currently recommended as a standard treatment for increased intracranial pressure in any clinical setting. However, recent studies suggest that hypothermia can lower ICP and may improve patient outcomes. Hypothermia also appeared to be effective in lowering ICP after other therapies have failed.

Patients that undergo Therapeutic Hypothermia do not all respond in the same physiologic manner. Some patients have a very strong shiver response that requires multiple large doses of sedation medications to control while others have only mild or no shivering response at all. Similarly, the effects on patient heart rate, blood pressure, coagulation factors, white blood cells and blood sugar are all widely variable. This would indicate that some patients are just better suited to handle the physiologic effects of TH than others. In addition, there is some evidence from patients that have undergone repeat cycles of Therapeutic Hypothermia that the body becomes accustomed to the physical changes that occur, resulting in decreased physiologic complications.

Because of this it would be feasible to place all available astronauts from the mission pool under short test cycles of TH and identify which ones are least likely to have complications. In addition, crew members that were mission critical or had moderate to mild complications may be able to be conditioned for the Torpor state by undergoing short repeat cycles.

 

Please submit any additional questions to: spacetorpor@sei.aero

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