U-2 pilots - high alt - white brain lesions
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U-2 pilots - high alt - white brain lesions
http://www.medscape.com/viewarticle/809899
operating at 9000m (27kft) cabin alt.
all looks a bit unsure of the impact or relevance at the moment to other high alt ops.
any rumours of an impact on FJ or even high alt AD ops?
operating at 9000m (27kft) cabin alt.
all looks a bit unsure of the impact or relevance at the moment to other high alt ops.
any rumours of an impact on FJ or even high alt AD ops?
I don't own this space under my name. I should have leased it while I still could
Many RAF Types operated with cabin altitudes of 27k. Perhaps the longest sorties would have been with the Comet 2 but the Canberra B2 possibly quite long too.
Shorter duration, but greater altitudes, would have included the Meteor.
Shorter duration, but greater altitudes, would have included the Meteor.
Ecce Homo! Loquitur...
Killer at 70,000 Feet
Recent Severe CNS Altitude Decompression Sickness (DCS) in U-2 Pilots
Cohort study of multiple brain lesions in sport divers
.......Main outcome measures: Presence of multiple brain lesions visualised by cranial magnetic resonance imaging and presence and size of patent foramen ovale as documented by echocontrast transcranial Doppler ultrasonography.
Results: 25 subjects were found to have a right-to-left shunt, 13 with a patent foramen ovale of high haemodynamic relevance. A total of 41 brain lesions were detected in 11 divers. There were seven brain lesions in seven divers without a right-to-left shunt and 34 lesions in four divers with a right-to-left shunt. Multiple brain lesions occurred exclusively in three divers with a large patent foramen ovale (P=0.004).
Recent Severe CNS Altitude Decompression Sickness (DCS) in U-2 Pilots
Cohort study of multiple brain lesions in sport divers
.......Main outcome measures: Presence of multiple brain lesions visualised by cranial magnetic resonance imaging and presence and size of patent foramen ovale as documented by echocontrast transcranial Doppler ultrasonography.
Results: 25 subjects were found to have a right-to-left shunt, 13 with a patent foramen ovale of high haemodynamic relevance. A total of 41 brain lesions were detected in 11 divers. There were seven brain lesions in seven divers without a right-to-left shunt and 34 lesions in four divers with a right-to-left shunt. Multiple brain lesions occurred exclusively in three divers with a large patent foramen ovale (P=0.004).
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Is this symptomatic of the 30% of us with PFO or are the articles related to PFO just an aside? Can't read the original article as I don't have a login.
Any pathalogical issues with PFO at lower cabalt, say 8-10k?
Any pathalogical issues with PFO at lower cabalt, say 8-10k?
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JFZ,
I too can't log on to the article. I would like to read it.
As PN says, I do recall some of the old bold 51 Sqn types talking about the early Comet having to fly at low cabin pressure.
Re AD of which I have a little peripheral knowledge. There was always a debate about the limits for Air Despatch and para that some did not understand. This was when we had the Interim system which gave a constant flow of 5 litres pm. the paras then got a demand system with a simplex regulator built into the mask. This was cleared to 18K in UK I do believe the US operated it much higher. I met a guy in YPG who claimed to have used it at 35K. (I think this was BS as I am not sure what consideration was given to the crew).
In about 1999 we got to 25K with a duplex Carleton regulator. The crew had the old 317A Harrier surplus since the aircraft system was no good for pre breathing. Meggitt then produced a new regulator based on the 417 that had a duplex 100% arrangement but no air mix. this was tested higher but RTS was only granted to 25K. The Docs at Farnborough were listened to. I think this was a sound decision.
I note from the A400M propaganda they are looking at 35K for AD (I hope they are not reliant on the OBOGs which does not filter out the Argon). the latest system we had on the 130 had the intermediate pressure set at 350psi to match the ring main on the A400M. We were quite forward thinking as A400M was probably 10 years away.
There was quite a few in the wider community who just did not have a clue about the effects of altitude.
It's some time since I lost touch.
I too can't log on to the article. I would like to read it.
As PN says, I do recall some of the old bold 51 Sqn types talking about the early Comet having to fly at low cabin pressure.
Re AD of which I have a little peripheral knowledge. There was always a debate about the limits for Air Despatch and para that some did not understand. This was when we had the Interim system which gave a constant flow of 5 litres pm. the paras then got a demand system with a simplex regulator built into the mask. This was cleared to 18K in UK I do believe the US operated it much higher. I met a guy in YPG who claimed to have used it at 35K. (I think this was BS as I am not sure what consideration was given to the crew).
In about 1999 we got to 25K with a duplex Carleton regulator. The crew had the old 317A Harrier surplus since the aircraft system was no good for pre breathing. Meggitt then produced a new regulator based on the 417 that had a duplex 100% arrangement but no air mix. this was tested higher but RTS was only granted to 25K. The Docs at Farnborough were listened to. I think this was a sound decision.
I note from the A400M propaganda they are looking at 35K for AD (I hope they are not reliant on the OBOGs which does not filter out the Argon). the latest system we had on the 130 had the intermediate pressure set at 350psi to match the ring main on the A400M. We were quite forward thinking as A400M was probably 10 years away.
There was quite a few in the wider community who just did not have a clue about the effects of altitude.
It's some time since I lost touch.
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if you google "u-2 white lesions" my original link is around the 3rd, the url is medscape.
I'm guessing a short depress for AD at 25k ft is quite different to prolonged period with a 27k ft cabin alt pressure in a U2, but I'm not sure I understand the U-2 spacesuit set up - is the suit at a higher pressure, what do they breathe?
I'm guessing a short depress for AD at 25k ft is quite different to prolonged period with a 27k ft cabin alt pressure in a U2, but I'm not sure I understand the U-2 spacesuit set up - is the suit at a higher pressure, what do they breathe?
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But it is not clear what the results indicate:
"We have been unable to identify any clinical deficits in any of the U-2 pilots studied, and all of the U-2 pilots that were part of this study are still performing the extremely complex tasks associated with flying the U-2 plane," he noted. "What we do not know is the long-term implication of these findings, nor what the threshold might be for inciting clinical symptoms," Dr. McGuire added.
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yes, it does seem a bit unclear.
the case of the bends inthe link above may have been down to a prebreathing issue or something as it seems he had n2 in his blood - if i understand the cause of the bends correctly.
the case of the bends inthe link above may have been down to a prebreathing issue or something as it seems he had n2 in his blood - if i understand the cause of the bends correctly.
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JFZ, The most understandable description I have read about the workings of the high altitude suit and regime is in Rich Grahams book on the SR71 revealed - the inside story. I believe the U2 and SR use the same suit.
I did have a look around my study for my RAFCAM course notes. Can't find them for the moment.
I did have a look around my study for my RAFCAM course notes. Can't find them for the moment.
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With SCUBA diving it isn't how deep you go or how long you stay there. It is how quickly you come up. Especially the last few metres when the % change is the greatest.
In recent years doppler ultrasound has been used to detect microbubble formation, so the science is increasingly well understood.
What is amazing is how Haldane's empirical approach, done during WW1, still stands up today with compartments, half times, diffusion and on/off gassing.
Most divers today carry a computer that measures pressure and time, applying them to an algorithm and then informing the diver how to act. The more sophisticated of these also continually analyse the gas mix that the diver is breathing and apply this to the algorithm.
When doing ordinary no decompression stop diving I tend to follow the following rules. When ascending stop at half maximum depth for two minutes, this allows the full circulation to pass through the lungs, removing microbubbles. A further 2 minute stop at half the remaining depth (ie 25% of maximum depth). Repeat till a 2 minute stop at 6 metres, then again at 3 metres. Ascending very slowly from 6 metres to 3 metres to the surface.
Once ascent has been started never descend again as it allows microbubbles to get over to the arterial side.
PADI recommend a 3 minute safety stop at 5 metres. This is easier for most novice divers than 3 metres. However I see most divers make this stop then fin straight up to the surface. This is very silly as a fast ascent when the % change is so high is asking for problems.
In recent years doppler ultrasound has been used to detect microbubble formation, so the science is increasingly well understood.
What is amazing is how Haldane's empirical approach, done during WW1, still stands up today with compartments, half times, diffusion and on/off gassing.
Most divers today carry a computer that measures pressure and time, applying them to an algorithm and then informing the diver how to act. The more sophisticated of these also continually analyse the gas mix that the diver is breathing and apply this to the algorithm.
When doing ordinary no decompression stop diving I tend to follow the following rules. When ascending stop at half maximum depth for two minutes, this allows the full circulation to pass through the lungs, removing microbubbles. A further 2 minute stop at half the remaining depth (ie 25% of maximum depth). Repeat till a 2 minute stop at 6 metres, then again at 3 metres. Ascending very slowly from 6 metres to 3 metres to the surface.
Once ascent has been started never descend again as it allows microbubbles to get over to the arterial side.
PADI recommend a 3 minute safety stop at 5 metres. This is easier for most novice divers than 3 metres. However I see most divers make this stop then fin straight up to the surface. This is very silly as a fast ascent when the % change is so high is asking for problems.
I don't own this space under my name. I should have leased it while I still could
Talking of high altitude AD, the Cub had a pressurised crew compartment and an pressurised freight bay. I don't know if the freight bay could be separately pressurised.
Whilst I have heard of aircrew suffering "bends" at altitude, I have never heard of anyone suffering altitude sickness in the air, although I understand it can occur unpredictably above 10 or 12k feet when mountaineering. Anyone have any knowledge in that area?
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There are 14 peaks in the world over 8,000 metres. All have been climbed without supplementary oxygen, after acclimatisation.
The death rate for climbers attempting them is horrendous: List of deaths on eight-thousanders - Wikipedia, the free encyclopedia
There have been many feats of outstanding skill on these mountains. But climbers call the high altitude the death zone, where if you stop to help someone in trouble you will both end up dead. And there are lots of bodies still on the mountains that cannot be brought down.
Wikipedia have a good article on the effect of high altitude on humans with many references that can be followed: Effects of high altitude on humans - Wikipedia, the free encyclopedia
The death rate for climbers attempting them is horrendous: List of deaths on eight-thousanders - Wikipedia, the free encyclopedia
There have been many feats of outstanding skill on these mountains. But climbers call the high altitude the death zone, where if you stop to help someone in trouble you will both end up dead. And there are lots of bodies still on the mountains that cannot be brought down.
Wikipedia have a good article on the effect of high altitude on humans with many references that can be followed: Effects of high altitude on humans - Wikipedia, the free encyclopedia
Talking of high altitude AD, the Cub had a pressurised crew compartment and an pressurised freight bay. I don't know if the freight bay could be separately pressurised.
The ELINT Cubs were a different matter , B to D etc. and some at least had pressurisation in the main cabin , operating quite a bit higher - as you will probably recall.
