Brain damge found at high cockpit altitudes

'Mental-decline brain lesions' found in high-flying military pilots

Aviators piloting aircraft at very high altitudes for the military have "significantly more" brain lesions known as white matter hyperintensities, US Air Force medical researchers have found through MRI scanning.
The study, published in Neurology, compared the MRI images from 102 USAF pilots of the U-2 reconnaissance aircraft with brain scans from 91 controls matched for age, health and education levels.

The U-2 Dragon Lady is an aircraft made by Lockheed Martin, originally designed to go high enough to evade destruction by Soviet anti-aircraft fire during surveillance missions in the Cold War.

It flies at altitudes above about 69,000 feet (above 21,000 meters) and maintains a cabin altitude - the altitude equivalent kept inside the cockpit or cabin of an aircraft - of between 28,000 and 30,000 feet.

More at http://www.medicalnewstoday.com/articles/265036.php

I KNEW there was something "different" about Heinz W !

No longer! The USAF, under the "CARE" program has reduced U2 equivalent cabin pressure from 30K feet to 15K feet.

Caution: Hypobaric Pressure- Regarding perhaps a more interesting study related to the Perlan 2 project. Our institute was asked to evaluate U-2 pilots following an increase in frequency of decompression sickness. The study found a significant number of white-matter lesions (e.g, stroke-like) in the brain of affected subjects. Some pilots (while in flight) were nearly incapacitated and others suffered long-term neurological changes. Why? The thinking is that these pilots operate at 70,000ft but cabin/suit pressure is maintained at only around 30,000ft!! I've heard mention that the Air Force is/has changing that to 15,000ft pressure alt (2013 cabin altitude reduction effort (CARE)). The Perlan 2 glider is pressurized to 14,000ft, according to their website info.


Public-distilled summary of findings:
http://www.reuters.com/article/us-he...97M0RT20130823
Original article:
https://www.ncbi.nlm.nih.gov/pmc/art...ihms488856.pdf
Mike

On Tuesday, November 8, 2016 at 4:15:59 PM UTC-5, Duster wrote:
No longer! The USAF, under the "CARE" program has reduced U2 equivalent cabin pressure from 30K feet to 15K feet.

Caution: Hypobaric Pressure- Regarding perhaps a more interesting study related to the Perlan 2 project. Our institute was asked to evaluate U-2 pilots following an increase in frequency of decompression sickness. The study found a significant number of white-matter lesions (e.g, stroke-like) in the brain of affected subjects. Some pilots (while in flight) were nearly incapacitated and others suffered long-term neurological changes. Why? The thinking is that these pilots operate at 70,000ft but cabin/suit pressure is maintained at only around 30,000ft!! I've heard mention that the Air Force is/has changing that to 15,000ft pressure alt (2013 cabin altitude reduction effort (CARE)). The Perlan 2 glider is pressurized to 14,000ft, according to their website info.


Public-distilled summary of findings:
http://www.reuters.com/article/us-he...97M0RT20130823
Original article:
https://www.ncbi.nlm.nih.gov/pmc/art...ihms488856.pdf
Mike

Wow....I would think G-force and lack of oxygen to the brain would be a cause before high alt.

It's all about getting oxygen to brain tissue (oxygen exchange efficiency), and avoiding embolism (aka "the bends"), not so much % O2 that's available to breath. At those altitudes, breathing 100% oxygen is about as efficient as breathing air at around 12,000ft (someone correct me if I'm off). Hence the need to increase "cabin" pressure in the Perlan 2 and as the USAF is doing now with the U2's. Remember Robert Harris and his 1986 49,009ft altitude record was done in an unpressurized Grob 102. He was forced to come down when his O2 system started to fail, apparently suffering from medical issues for some time thereafter. Now it kinda makes sense why Perlan 1 (Fossett) spent all that time and money to best Bickle's flight by only 1,600ft wearing NASA spacesuits with Enevoldson.

It has to do with the partial pressure of oxygen in the blood compared
to ppO2 in the ambient (cabin, space suit, etc.). PpO2 outside the body
has to be higher than PpO2 in the blood or no oxygen will get in.
Pressure breathing helps to a point, but it won't help at U2 or Perlan
altitudes. They have to be pressurized, either suit or cabin.

On 11/9/2016 1:42 PM, Duster wrote:
It's all about getting oxygen to brain tissue (oxygen exchange efficiency), and avoiding embolism (aka "the bends"), not so much % O2 that's available to breath. At those altitudes, breathing 100% oxygen is about as efficient as breathing air at around 12,000ft (someone correct me if I'm off). Hence the need to increase "cabin" pressure in the Perlan 2 and as the USAF is doing now with the U2's. Remember Robert Harris and his 1986 49,009ft altitude record was done in an unpressurized Grob 102. He was forced to come down when his O2 system started to fail, apparently suffering from medical issues for some time thereafter. Now it kinda makes sense why Perlan 1 (Fossett) spent all that time and money to best Bickle's flight by only 1,600ft wearing NASA spacesuits with Enevoldson.

--
Dan, 5J

This post might be a good explanation for some of the long winded posters here on RAS.

Boggs

The U2 guys wear suits.


On Wednesday, November 9, 2016 at 4:46:27 PM UTC-8, Dan Marotta wrote:
It has to do with the partial pressure of oxygen in the blood compared
to ppO2 in the ambient (cabin, space suit, etc.). PpO2 outside the body
has to be higher than PpO2 in the blood or no oxygen will get in.
Pressure breathing helps to a point, but it won't help at U2 or Perlan
altitudes. They have to be pressurized, either suit or cabin.

On 11/9/2016 1:42 PM, Duster wrote:
It's all about getting oxygen to brain tissue (oxygen exchange efficiency), and avoiding embolism (aka "the bends"), not so much % O2 that's available to breath. At those altitudes, breathing 100% oxygen is about as efficient as breathing air at around 12,000ft (someone correct me if I'm off). Hence the need to increase "cabin" pressure in the Perlan 2 and as the USAF is doing now with the U2's. Remember Robert Harris and his 1986 49,009ft altitude record was done in an unpressurized Grob 102. He was forced to come down when his O2 system started to fail, apparently suffering from medical issues for some time thereafter. Now it kinda makes sense why Perlan 1 (Fossett) spent all that time and money to best Bickle's flight by only 1,600ft wearing NASA spacesuits with Enevoldson.

--
Dan, 5J

Bono and the band wearing suits? The pilots can't fully operate a complex cockpit like the U2 with their suits inflated....too bulky, so my understanding is that they only are pressurized if the cockpit seal is compromised.

It's not the relative PO2/PaO2 alveolar-arterial ratio that's key, it's the minimum absolute alveolar PO2 value (~14kPa) that is necessary to keep us alive. Even an adequate PO2/PaO2 gradient that allows efficient O2 diffusion won't be sufficient if that value is much lower.

On Wednesday, November 9, 2016 at 1:42:05 PM UTC-7, Duster wrote:
It's all about getting oxygen to brain tissue (oxygen exchange efficiency), and avoiding embolism (aka "the bends"), not so much % O2 that's available to breath. At those altitudes, breathing 100% oxygen is about as efficient as breathing air at around 12,000ft (someone correct me if I'm off). Hence the need to increase "cabin" pressure in the Perlan 2 and as the USAF is doing now with the U2's. Remember Robert Harris and his 1986 49,009ft altitude record was done in an unpressurized Grob 102. He was forced to come down when his O2 system started to fail, apparently suffering from medical issues for some time thereafter. Now it kinda makes sense why Perlan 1 (Fossett) spent all that time and money to best Bickle's flight by only 1,600ft wearing NASA spacesuits with Enevoldson.

https://jonathanturley.org/2013/09/0...r-all-seasons/