No such thing as Economy Class Syndrome
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No such thing as Economy Class Syndrome
Hi Pprunes,
I've been reading a variety of comments on these fora concerning the putative 'economy class syndrome' and would like to suggest that there is no such thing.
I think the phrase entered our lexicon in the late 1980s, possibly after a paper in The Lancet (Cruickshank et al. Air travel & thrombotic episodes: the economy class syndrome. Lancet 1988, ii, 497-98). The phrase has certainly been bandied around a lot and from physiological first-priciples seems to make sense:
- Dehydration and relative inactivity are felt to be predisposing factors for the formation of thromboses;
- Dehydration and relative inactivity, often for prolonged periods, are common during passenger air travel.
One problem, however, is that there has been virtually no scientific research that has been well structured and provides credible results that stand-up to rigorous scrutiny. A recent study, again published in Lancet, may be the start of a trend towards credible scientific research on the issue.
The report (Kraaijenhagen et al, Travel and risk of venous thrombosis, Lancet, 356;9240 of 28OCT00) can be found on the Lancet website at http://www.thelancet.com/journal/vol...search.14016.1 (you may have to enroll, for free, to get to it). This study analyses, with controls, the travel history of 788 patients with venous thrombosis and finds that having traveled by air, or road / rail / sea for that matter, does not increase the chance of getting a Deep Venous Thrombosis (DVT).
There is also a body of research developing that suggests that the folk who do get DVTs during flights have one of a number of underlying enzyme deficiencies / abnormalities.
While 'Economy Class Syndrome' is a title with great marketing potential, and certainly beloved of the media, lawyers, and the uninformed, there really is no evidence that such a syndrome actually exists ... what little evidence is available suggests otherwise (recall also that the plural of annecdote is not data).
Certainly people do get DVTs during and subsequent to flight ... but this is no more likely to happen than to similar people who do not fly.
Just my tuppence worth.
Sincerely
Dougal http://www.ozemail.com.au/~dxw/avmed.html
I've been reading a variety of comments on these fora concerning the putative 'economy class syndrome' and would like to suggest that there is no such thing.
I think the phrase entered our lexicon in the late 1980s, possibly after a paper in The Lancet (Cruickshank et al. Air travel & thrombotic episodes: the economy class syndrome. Lancet 1988, ii, 497-98). The phrase has certainly been bandied around a lot and from physiological first-priciples seems to make sense:
- Dehydration and relative inactivity are felt to be predisposing factors for the formation of thromboses;
- Dehydration and relative inactivity, often for prolonged periods, are common during passenger air travel.
One problem, however, is that there has been virtually no scientific research that has been well structured and provides credible results that stand-up to rigorous scrutiny. A recent study, again published in Lancet, may be the start of a trend towards credible scientific research on the issue.
The report (Kraaijenhagen et al, Travel and risk of venous thrombosis, Lancet, 356;9240 of 28OCT00) can be found on the Lancet website at http://www.thelancet.com/journal/vol...search.14016.1 (you may have to enroll, for free, to get to it). This study analyses, with controls, the travel history of 788 patients with venous thrombosis and finds that having traveled by air, or road / rail / sea for that matter, does not increase the chance of getting a Deep Venous Thrombosis (DVT).
There is also a body of research developing that suggests that the folk who do get DVTs during flights have one of a number of underlying enzyme deficiencies / abnormalities.
While 'Economy Class Syndrome' is a title with great marketing potential, and certainly beloved of the media, lawyers, and the uninformed, there really is no evidence that such a syndrome actually exists ... what little evidence is available suggests otherwise (recall also that the plural of annecdote is not data).
Certainly people do get DVTs during and subsequent to flight ... but this is no more likely to happen than to similar people who do not fly.
Just my tuppence worth.
Sincerely
Dougal http://www.ozemail.com.au/~dxw/avmed.html
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Re :dVT
I agree with the ideas expressed about lack of definitive studies into this problem. I disagree therefore that DVT due to flying does not occur.
What is interesting is that certain people are predisposed to DVT either due to medication, or another disease process. The reason for media and passenger interest in this is that at no stage do airlines inform passengers of the health risks associated with flying, and that is where the difficulty lies.
The real question is, are those flyers predisposed to DVT the only people who get DVT when flying? So far, that question has not been conclusively addressed in a suitable study. Indeed one of the difficulties with patients suffering from DVT is that the most severe effects may not become apparent until some time has elapsed and the passenger has gone home
If anything, the media attention has perhaps helped to push the aviation medical fraternity to consider this as more of a priority. That can only be a good thing.
Calling DVT from flying 'economy class syndrome' is just an easy way of talking about (deep breath!) Deep vein thrombosis occuring due to flying in cramped seating on a commercial aircraft. I really do not see a phrase like this as a problem (medical snobbery anyone?).
The misleading reports in newspapers ARE a problem.
If the studies have not been done then no one, not even the most senior physician can say that it does not occur.
To suggest that it does not occur is patently rubbish.
What is correct is that it seems to occur in certain types of patients for sure, but nobody has properly studied the problem.
i.e nobody really knows.
[This message has been edited by bigseat (edited 05 November 2000).]
I agree with the ideas expressed about lack of definitive studies into this problem. I disagree therefore that DVT due to flying does not occur.
What is interesting is that certain people are predisposed to DVT either due to medication, or another disease process. The reason for media and passenger interest in this is that at no stage do airlines inform passengers of the health risks associated with flying, and that is where the difficulty lies.
The real question is, are those flyers predisposed to DVT the only people who get DVT when flying? So far, that question has not been conclusively addressed in a suitable study. Indeed one of the difficulties with patients suffering from DVT is that the most severe effects may not become apparent until some time has elapsed and the passenger has gone home
If anything, the media attention has perhaps helped to push the aviation medical fraternity to consider this as more of a priority. That can only be a good thing.
Calling DVT from flying 'economy class syndrome' is just an easy way of talking about (deep breath!) Deep vein thrombosis occuring due to flying in cramped seating on a commercial aircraft. I really do not see a phrase like this as a problem (medical snobbery anyone?).
The misleading reports in newspapers ARE a problem.
If the studies have not been done then no one, not even the most senior physician can say that it does not occur.
To suggest that it does not occur is patently rubbish.
What is correct is that it seems to occur in certain types of patients for sure, but nobody has properly studied the problem.
i.e nobody really knows.
[This message has been edited by bigseat (edited 05 November 2000).]
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bigseat's repose (above) raises some very interesting thoughts:
> I agree with the ideas expressed about lack of definitive studies into this problem. I disagree therefore that DVT due to flying does not occur.
As I wrote in my earlier posting the data that is available and is credible indicates that air travellers are NOT at increased risk of DVT. Reading the papers mentioned should allay your concerns in this matter.
As for 'definitive studies' ... we all live in hope but so little of our scientitic knowledge base is built on definitive studies. Our knowledge tends to develop bit-by-bit as myriad not-so-definitive studies are interlinked and cross referenced.
> What is interesting is that certain people are predisposed to DVT either due to medication, or another disease process.
No doubt that some people are at higher risk of DVT than others ... all other things being equal. The big group you didn't mention is those with a malignant condition ... cancer.
> The reason for media and passenger interest in this is that at no stage do airlines inform passengers of the health risks associated with flying, and that is where the difficulty lies.
Ouch. I'm not sure that there is a right or wrong here. I have never received a risk-analysis sheet when I've ridden in a taxi ... I am much more likely to die in a taxi involved in a road accident than if I were to catch a bus. Are you proposing that all actvities that involve an increase risk should involve complete and detailed disclosure of all the known and potential risks? I suspect few amongst the travelling public would be willing to accept the extra couple of hours at the airport being briefed on these issues.
I think what will happen is that some semi-reasonable half-way measure will develop.
As for the airlines informing their passengers of risk .... read my previous post. Airline passengers are NOT at increased risk of DVT ... what are you suggesting they be informed about?
> The real question is, are those flyers predisposed to DVT the only people who get DVT when flying?
I doubt it .... a predisposition is just that. It means you're more likely to suffer the condition than another person. It does not mean that you're the only person who's gonna get the problem.
Perfectly healthy people can get DVTs out of the blue .... it's rare but it does happen. People with cancers are lots more likely to get DVTs. People who travel in aircraft, it would appear, are no more likely to get DVTs.
> So far, that question has not been conclusively addressed in a suitable study.
Vide supra concerning scientific research and the conclusivity of the results of any one study.
> Indeed one of the difficulties with patients suffering from DVT is that the most severe effects may not become apparent until some time has elapsed and the passenger has gone home.
Hmmmm ..... are we talking about patients or passengers here? People who get DVTs, be they patients, sportsfolk, professionals, musicians, travellers etc etc etc, often do not come to the notice of the medical profession for some days. This is, as you allude, usually because the DVT itself causes only rather subtle symptoms. It is often a catastrophic complication of the DVT that comes to the attention of the person and medical folk.
> If anything, the media attention has perhaps helped to push the aviation medical fraternity to consider this as more of a priority. That can only be a good thing.
:-) It doesn't take long for background attitudes and biases to become evident does it?
Anything that reduces the risk of injury to people, whether they're travelling or not, is uaully a good thing. Whether the end is always worth the means is another matter altogether.
> Calling DVT from flying 'economy class syndrome' is just an easy way of talking about (deep breath!)
Accurate terminology is very important when you're dealing with medicine or science. To simply make-up a fanciful, media-genic, if wholly inaccurate name is, IMHO, thoroughly inappropriate.
There is no evidence at all that DVT incidence relates to travelling in economy class of aircraft. There is no evidence that travelling in aircraft predisposes to the occurence of DVT.
There is ... as far as I can ascertain ... no evidence that DVTs occur because of flying in cramped seating.
> ..... (medical snobbery anyone?).
I guess that's one way of approaching an important issue.
> If the studies have not been done then no one, not even the most senior physician can say that it does not occur.
The evidence that is available does not indicate that air travel leads to an increased risk of DVT .... it wasn't very difficult to say. I suggest you actually read the evidence that is available.
> To suggest that it does not occur is patently rubbish.
I am happy to disagree with this statement and ... again ... suggest that you read the evidence that is available. Start with the references mentioned in my original post and then follow-up with the reports that they refer to.
To paraphrase the movie .... "Show me the data".
Cheers
Aeromed-Doc
> I agree with the ideas expressed about lack of definitive studies into this problem. I disagree therefore that DVT due to flying does not occur.
As I wrote in my earlier posting the data that is available and is credible indicates that air travellers are NOT at increased risk of DVT. Reading the papers mentioned should allay your concerns in this matter.
As for 'definitive studies' ... we all live in hope but so little of our scientitic knowledge base is built on definitive studies. Our knowledge tends to develop bit-by-bit as myriad not-so-definitive studies are interlinked and cross referenced.
> What is interesting is that certain people are predisposed to DVT either due to medication, or another disease process.
No doubt that some people are at higher risk of DVT than others ... all other things being equal. The big group you didn't mention is those with a malignant condition ... cancer.
> The reason for media and passenger interest in this is that at no stage do airlines inform passengers of the health risks associated with flying, and that is where the difficulty lies.
Ouch. I'm not sure that there is a right or wrong here. I have never received a risk-analysis sheet when I've ridden in a taxi ... I am much more likely to die in a taxi involved in a road accident than if I were to catch a bus. Are you proposing that all actvities that involve an increase risk should involve complete and detailed disclosure of all the known and potential risks? I suspect few amongst the travelling public would be willing to accept the extra couple of hours at the airport being briefed on these issues.
I think what will happen is that some semi-reasonable half-way measure will develop.
As for the airlines informing their passengers of risk .... read my previous post. Airline passengers are NOT at increased risk of DVT ... what are you suggesting they be informed about?
> The real question is, are those flyers predisposed to DVT the only people who get DVT when flying?
I doubt it .... a predisposition is just that. It means you're more likely to suffer the condition than another person. It does not mean that you're the only person who's gonna get the problem.
Perfectly healthy people can get DVTs out of the blue .... it's rare but it does happen. People with cancers are lots more likely to get DVTs. People who travel in aircraft, it would appear, are no more likely to get DVTs.
> So far, that question has not been conclusively addressed in a suitable study.
Vide supra concerning scientific research and the conclusivity of the results of any one study.
> Indeed one of the difficulties with patients suffering from DVT is that the most severe effects may not become apparent until some time has elapsed and the passenger has gone home.
Hmmmm ..... are we talking about patients or passengers here? People who get DVTs, be they patients, sportsfolk, professionals, musicians, travellers etc etc etc, often do not come to the notice of the medical profession for some days. This is, as you allude, usually because the DVT itself causes only rather subtle symptoms. It is often a catastrophic complication of the DVT that comes to the attention of the person and medical folk.
> If anything, the media attention has perhaps helped to push the aviation medical fraternity to consider this as more of a priority. That can only be a good thing.
:-) It doesn't take long for background attitudes and biases to become evident does it?
Anything that reduces the risk of injury to people, whether they're travelling or not, is uaully a good thing. Whether the end is always worth the means is another matter altogether.
> Calling DVT from flying 'economy class syndrome' is just an easy way of talking about (deep breath!)
Accurate terminology is very important when you're dealing with medicine or science. To simply make-up a fanciful, media-genic, if wholly inaccurate name is, IMHO, thoroughly inappropriate.
There is no evidence at all that DVT incidence relates to travelling in economy class of aircraft. There is no evidence that travelling in aircraft predisposes to the occurence of DVT.
There is ... as far as I can ascertain ... no evidence that DVTs occur because of flying in cramped seating.
> ..... (medical snobbery anyone?).
I guess that's one way of approaching an important issue.
> If the studies have not been done then no one, not even the most senior physician can say that it does not occur.
The evidence that is available does not indicate that air travel leads to an increased risk of DVT .... it wasn't very difficult to say. I suggest you actually read the evidence that is available.
> To suggest that it does not occur is patently rubbish.
I am happy to disagree with this statement and ... again ... suggest that you read the evidence that is available. Start with the references mentioned in my original post and then follow-up with the reports that they refer to.
To paraphrase the movie .... "Show me the data".
Cheers
Aeromed-Doc
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Aeromed,
It gets tiresome having to explain the obvious. If the evidence does not exist, then no one (including aero-med doc) can say for sure that the condition does not exist.
Trust me on this one.
If for example you are told their is a box which you cannot see, which is either red or black, and a few studies suggest the box is in fact a red colour, but others suggest it may be black. Can you know the colour? Of course not. This is a fundamental of scientific (as opposed to merely medical investigation). you could say it probably is black, but you cannot say it DEFINITELY is black. It's easy really. Concentrate.
QED, to say economy class syndrome does not exist is patently rubbish.
What is correct is to say it may OR may not. Nobody knows. Not even Aeromed.
Incidentally, in my experience anyone who responds to a comment on medical snobbery is invariably guilty of same. In this case, carping pedantry to boot.
Grow up!
[This message has been edited by bigseat (edited 07 November 2000).]
It gets tiresome having to explain the obvious. If the evidence does not exist, then no one (including aero-med doc) can say for sure that the condition does not exist.
Trust me on this one.
If for example you are told their is a box which you cannot see, which is either red or black, and a few studies suggest the box is in fact a red colour, but others suggest it may be black. Can you know the colour? Of course not. This is a fundamental of scientific (as opposed to merely medical investigation). you could say it probably is black, but you cannot say it DEFINITELY is black. It's easy really. Concentrate.
QED, to say economy class syndrome does not exist is patently rubbish.
What is correct is to say it may OR may not. Nobody knows. Not even Aeromed.
Incidentally, in my experience anyone who responds to a comment on medical snobbery is invariably guilty of same. In this case, carping pedantry to boot.
Grow up!
[This message has been edited by bigseat (edited 07 November 2000).]
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Gee bigseat, 'fraid you have to run that one past me one more time.
"If the evidence does not exist, then no one....can say for sure that the condition does not exist."
So if there is no evidence that something exists, that doesn't mean to say that it doesn't? Well, if there is no evidence that something exists there seems little sense in assuming that perversely it does anyway.
"Trust me on this one." Why should I/we? Who are you?
You red/black box story is a variant of the Shrödinger's Cat paradox - actually the box is neither red NOR black...
"This is a fundamental of scientific (as opposed to merely medical investigation)..... "
????
All this concentration on b*ll*cks is giving me a headache.
Reminds me of the story about the chap who went around scattering little scraps of paper on the pavement - "To keep the tigers away!"
"But there are no tigers in Llangerrub!"
"See! It works!"
"If the evidence does not exist, then no one....can say for sure that the condition does not exist."
So if there is no evidence that something exists, that doesn't mean to say that it doesn't? Well, if there is no evidence that something exists there seems little sense in assuming that perversely it does anyway.
"Trust me on this one." Why should I/we? Who are you?
You red/black box story is a variant of the Shrödinger's Cat paradox - actually the box is neither red NOR black...
"This is a fundamental of scientific (as opposed to merely medical investigation)..... "
????
All this concentration on b*ll*cks is giving me a headache.
Reminds me of the story about the chap who went around scattering little scraps of paper on the pavement - "To keep the tigers away!"
"But there are no tigers in Llangerrub!"
"See! It works!"
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In response to bigseat's most recent response:
> It gets tiresome having to explain the obvious.
Yes, it is very difficult wehen you're having to be so patient and understanding with ignoramuses. I apologise for making your life so hard and having such difficulty in understanding your concepts. I will try very hard to understand ... please forgive me my failings.
> If the evidence does not exist, then no one (including aero-med doc) can say for sure that the condition does not exist.
I think it was Mac the Knife that used the 'b' word. Modern medicine is scientific and evidence based. The existence of conditions and syndromes is based on the existence of credible and widely supported evidence to that effect.
Could there be a link between air travel and DVT? Sure there COULD but the available evidence does not support that link.
> Trust me on this one.
Yeah sure and 'Trust me I'm a doctor' is also a valid debate closer.
> If for example you are told their is a box which you cannot see, which is either red or black, and a few studies suggest the box is in fact a red colour, but others suggest it may be black.
Ohhh, c'mon ... get serious. If you're going to quote paradoxes from quantum theory you might want to get them right. In Shrödinger's Cat paradox the cat, or in your case the box, is NEITHER black nor red. A corollary is that, in part, the process of observation changes the nature of the observed.
Some of the recent work with paired particles (I think that's the term) has, however, started to suggest that the Shrödinger's Cat paradox is also not that accurate at the quantum level ... and that it is possible to determine the colour of the cat without opening the box.
I am not a quantum physicist so am treading tenuous ground here:-)
In the example we're discussing there is evidence ... it simply fails to support the premise that air travel causes DVT. We're not dealing with paired photons in quantum space.
> This is a fundamental of scientific ...
That paradox is a paradox used to explain some of the vagaries of quantum theory. Quantum theory is just that a THEORY and although it does presently explain many of the observations made on subatomic activities it may well be superceded, or incoporated, as string theory or any number of grand unifying theories continue to evolve ... it is NOT a fundamental of modern science.
> It's easy really. Concentrate.
You're right, not too difficult at all.
> QED, to say economy class syndrome does not exist is patently rubbish.
I think, if you were to take the time to read my post, you'd find that what I wrote was "While 'Economy Class Syndrome' is a title with great marketing potential, and certainly beloved of the media, lawyers, and the uninformed, there really is no evidence that such a syndrome actually exists ... what little evidence is available suggests otherwise."
The catch-line is that there is no evidence that such a syndrome actaull exists.
> What is correct is to say it may OR may not. Nobody knows. Not even Aeromed.
The balance of the available evidence fails to support the existence of such a syndrome. Certainly such a syndrome COULD exist ... vide supra.
> Incidentally, in my experience anyone who responds to a comment on medical snobbery is invariably guilty of same. In this case, carping pedantry to boot.
Wow! I am impressed. Do you have a habit of making comments about 'medical snobbery' just to determine the sort of person you're delaing with from whether you'll get a response or not?
Oh dear. I'm sorry this diuscussion is causing you so much pain bigseat.
> Grow up!
Ah yes, personal attack and accusation is a very sensible and useful tool in an important debate. Will I be accused of acting like Hitler next ... that's the usual follow-on after personal attacks when someone has placed themselves out of their depth in an internet debate.
Cheers
Aeromed-Doc
> It gets tiresome having to explain the obvious.
Yes, it is very difficult wehen you're having to be so patient and understanding with ignoramuses. I apologise for making your life so hard and having such difficulty in understanding your concepts. I will try very hard to understand ... please forgive me my failings.
> If the evidence does not exist, then no one (including aero-med doc) can say for sure that the condition does not exist.
I think it was Mac the Knife that used the 'b' word. Modern medicine is scientific and evidence based. The existence of conditions and syndromes is based on the existence of credible and widely supported evidence to that effect.
Could there be a link between air travel and DVT? Sure there COULD but the available evidence does not support that link.
> Trust me on this one.
Yeah sure and 'Trust me I'm a doctor' is also a valid debate closer.
> If for example you are told their is a box which you cannot see, which is either red or black, and a few studies suggest the box is in fact a red colour, but others suggest it may be black.
Ohhh, c'mon ... get serious. If you're going to quote paradoxes from quantum theory you might want to get them right. In Shrödinger's Cat paradox the cat, or in your case the box, is NEITHER black nor red. A corollary is that, in part, the process of observation changes the nature of the observed.
Some of the recent work with paired particles (I think that's the term) has, however, started to suggest that the Shrödinger's Cat paradox is also not that accurate at the quantum level ... and that it is possible to determine the colour of the cat without opening the box.
I am not a quantum physicist so am treading tenuous ground here:-)
In the example we're discussing there is evidence ... it simply fails to support the premise that air travel causes DVT. We're not dealing with paired photons in quantum space.
> This is a fundamental of scientific ...
That paradox is a paradox used to explain some of the vagaries of quantum theory. Quantum theory is just that a THEORY and although it does presently explain many of the observations made on subatomic activities it may well be superceded, or incoporated, as string theory or any number of grand unifying theories continue to evolve ... it is NOT a fundamental of modern science.
> It's easy really. Concentrate.
You're right, not too difficult at all.
> QED, to say economy class syndrome does not exist is patently rubbish.
I think, if you were to take the time to read my post, you'd find that what I wrote was "While 'Economy Class Syndrome' is a title with great marketing potential, and certainly beloved of the media, lawyers, and the uninformed, there really is no evidence that such a syndrome actually exists ... what little evidence is available suggests otherwise."
The catch-line is that there is no evidence that such a syndrome actaull exists.
> What is correct is to say it may OR may not. Nobody knows. Not even Aeromed.
The balance of the available evidence fails to support the existence of such a syndrome. Certainly such a syndrome COULD exist ... vide supra.
> Incidentally, in my experience anyone who responds to a comment on medical snobbery is invariably guilty of same. In this case, carping pedantry to boot.
Wow! I am impressed. Do you have a habit of making comments about 'medical snobbery' just to determine the sort of person you're delaing with from whether you'll get a response or not?
Oh dear. I'm sorry this diuscussion is causing you so much pain bigseat.
> Grow up!
Ah yes, personal attack and accusation is a very sensible and useful tool in an important debate. Will I be accused of acting like Hitler next ... that's the usual follow-on after personal attacks when someone has placed themselves out of their depth in an internet debate.
Cheers
Aeromed-Doc
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Aeromed Doc
You seem like an educated and well-informed sort of chap. Yet you dismiss an early study and use a more recent one (again, a single study) to support your contention that ECS doesn't exist.
But just to pull it back to the real world for a moment, surely you'll agree that a low pressure environment, lack of leg movement/exercise, poor quality air, dehydration are all contributory factors?
And yet you state definitively (on the slenderest of 'evidence') that airline passengers are not more likely to suffer a DVT.
I'm unhappy about challenging a professional on his own turf, but would gently ask whether you're not being over-selective in your interpretation of the evidence (formal and anecdotal). There are some studies which do suggest that the condition exists, and that it's more likely to occur in cramped (economy class) conditions. Furthermore, there seems to be a growing consensus (even among aeromed specialists, including to sources at IAM) that the problem is real.
And while we are perhaps some way from definitive proof, good sense would surely indicate that some sensible precautions (like giving pax more leg room) would be sensible, and not beyond either the wit or the pockets of major airlines on the longer-range routes?
In a post over on R & N, Latest states that "There is a research paper to be published in the Lancet medical journal tomorrow that will say that economy class syndrome does exist and should be recognised by the airlines.
This study was by Norwegian scientists who put 20 healthy men into a specially constructed aparment in which the air pressure was as low as in an aeroplane. Then they were exposed to a rapid decrease in air pressure, similar to that experienced in a flight. They were allowed to carry out everyday activities but not physical exercise. The scientists found that levels of compounds associated with blood clotting increased between 2 and 8-fold in the men."
I wonder what the effect would have been if they'd been confined (for hours at a time) in economy class seats and kept dehydrated, too? I'm afraid Latest doesn't provide us with a handy link citing stacks of learned paper, but the point is that this is a controversial study, and that surely caution and precaution is better than apparently authoritative reassurances given by people on the basis of incomplete and partial research?
Mac the Knife: Proper studies do indeed eliminate garbage. But you do need studies, plural, and you must take account of those which contradict your preconceived ideas, as well as those which support them.
TG: Perhaps some open-mind medicine might also be of use?
You seem like an educated and well-informed sort of chap. Yet you dismiss an early study and use a more recent one (again, a single study) to support your contention that ECS doesn't exist.
But just to pull it back to the real world for a moment, surely you'll agree that a low pressure environment, lack of leg movement/exercise, poor quality air, dehydration are all contributory factors?
And yet you state definitively (on the slenderest of 'evidence') that airline passengers are not more likely to suffer a DVT.
I'm unhappy about challenging a professional on his own turf, but would gently ask whether you're not being over-selective in your interpretation of the evidence (formal and anecdotal). There are some studies which do suggest that the condition exists, and that it's more likely to occur in cramped (economy class) conditions. Furthermore, there seems to be a growing consensus (even among aeromed specialists, including to sources at IAM) that the problem is real.
And while we are perhaps some way from definitive proof, good sense would surely indicate that some sensible precautions (like giving pax more leg room) would be sensible, and not beyond either the wit or the pockets of major airlines on the longer-range routes?
In a post over on R & N, Latest states that "There is a research paper to be published in the Lancet medical journal tomorrow that will say that economy class syndrome does exist and should be recognised by the airlines.
This study was by Norwegian scientists who put 20 healthy men into a specially constructed aparment in which the air pressure was as low as in an aeroplane. Then they were exposed to a rapid decrease in air pressure, similar to that experienced in a flight. They were allowed to carry out everyday activities but not physical exercise. The scientists found that levels of compounds associated with blood clotting increased between 2 and 8-fold in the men."
I wonder what the effect would have been if they'd been confined (for hours at a time) in economy class seats and kept dehydrated, too? I'm afraid Latest doesn't provide us with a handy link citing stacks of learned paper, but the point is that this is a controversial study, and that surely caution and precaution is better than apparently authoritative reassurances given by people on the basis of incomplete and partial research?
Mac the Knife: Proper studies do indeed eliminate garbage. But you do need studies, plural, and you must take account of those which contradict your preconceived ideas, as well as those which support them.
TG: Perhaps some open-mind medicine might also be of use?
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Jackonicko - Aeromed-Doc is not dismissing the early Lancet study, which was really more of a trial balloon to see what people though about the matter and establish "I thought-about-it-first" rights. The Lancet study is a far more serious piece of work.
I would agree that on the surface all the factors that you (and other people) have cited would appear to predispose pax to DVTs. The sensible thing then is to set up a study and see if there is any evidence to support such a hypothesis. This was done by Kraaijenhagen et al. and perhaps rather to their surprise and chagrin no evidence was found (it can be disappointing when nothing surfaces to support one's study!).
I would agree, that by published articles alone, the evidence "con" is slender, but on the other hand we do not actually have much evidence "pro" either, apart from a few anecdotes of people who have presented with DVTs after flying.
Nothing, after all, is harder than proving the negative case.
Can we try and get it in perspective? JN - you perhaps more than anyone else would know how many billion-zillion airmiles are flown by pax globally every year. Docs DO actually talk to each other and are in fact keen to pick up things. If GPs and specialists were seeing significant numbers of pts. with DVTs/PEs soon after a trip it is likely that it would have been noticed - the situation is 25 years old! Lets try some facts:
DVTs are not a good idea because:
a) A good going DVT can stuff up venous return from the lower limb fairly permanently - pts. may have lasting symptoms of swelling and pain.
b) A DVT thrombus (clot) can detach itself and lodge in the lung, a pulmonary embolus (PE). A good sized PE can kill you dead very fast.
Unfortunately (or fortunately):
a) Most DVTs are mild and virtually asymptomatic, resolving spontaneously with no sequelae.
b) There is little correlation between the clinical severity of the initial DVT and the chances of a life threatening PE. In fact, most fatal PEs seem to occur after mild and un-noticed DVTs rather than big obvious ones.
c) Most PEs are minor and asyptomatic and go undiagnosed and un-noticed.
Perhaps 1/100 is noticed and 1/1000 is fatal.
DVTs/PEs are a significant problem in hospitals, mainly because few of us will ever forget those patients of ours who (after surgery/trauma ranging from the trivial to the severe) unexpectedly dropped dead from a massive PE.
Much attention has been given to preventing DVTs/PE, ranging from aspirin to heparin to early mobilisation to compression stockings etc., etc.
We have a rough idea which patients are most at risk (obese, cancer, immobile, pelvic surgery) and take precautions. Unfortunately there is still considerable controversy as to how effective these precautions are, with some quoting studies one way and some another.
Unfortunately, these days the matter is more legal than science driven.
Patients tend to receive anti-thromboembolism prophylaxis more on the basis of heading off lawsuits than on firm scientific grounds. I for instance, will use appropriate prophylaxis for at risk patients, but (having had a couple die in spite of ALL measures) feel in my heart of hearts that if it's going to happen then it's going to happen.
So the issue of passenger leg-room will probably (like so many issues in our society) become driven by lawyers and the third estate rather than by proper science. Airlines will compute a cost/benefit equation which relates cost of possibly lost (or more likely, conceded uncontested) lawsuits to cost of increasing seat separation and come out with an appropriate number.
Increased airline costs will simply be passed back to the pax, with a microcopic individual medical benefit. OK by me, if that is what society wants.
As for the Norwegian study, I do not doubt it's findings for a minute. Whether an increase in levels of compounds associated with blood clotting translates into a real increased risk of DVT is something else.
I agree wholeheartedly that we need further studies (doesn't everything?), but current evidence really does not point towards airline passenger DVTs being a major epidemiological phenomenon.
I'm sorry that you interpret my thoughts based on current evidence as being a sign of preconceived ideas. I am just as interested and concerned about the truth as you are - there are, after all, my patients! I hope that we are not getting into a situation where professionals have to say "Yessir nossir!" to any crusades that the press takes up for fear of being labelled obstructive and reactionary and being publicly pilloried.
Cheers Mac
I would agree that on the surface all the factors that you (and other people) have cited would appear to predispose pax to DVTs. The sensible thing then is to set up a study and see if there is any evidence to support such a hypothesis. This was done by Kraaijenhagen et al. and perhaps rather to their surprise and chagrin no evidence was found (it can be disappointing when nothing surfaces to support one's study!).
I would agree, that by published articles alone, the evidence "con" is slender, but on the other hand we do not actually have much evidence "pro" either, apart from a few anecdotes of people who have presented with DVTs after flying.
Nothing, after all, is harder than proving the negative case.
Can we try and get it in perspective? JN - you perhaps more than anyone else would know how many billion-zillion airmiles are flown by pax globally every year. Docs DO actually talk to each other and are in fact keen to pick up things. If GPs and specialists were seeing significant numbers of pts. with DVTs/PEs soon after a trip it is likely that it would have been noticed - the situation is 25 years old! Lets try some facts:
DVTs are not a good idea because:
a) A good going DVT can stuff up venous return from the lower limb fairly permanently - pts. may have lasting symptoms of swelling and pain.
b) A DVT thrombus (clot) can detach itself and lodge in the lung, a pulmonary embolus (PE). A good sized PE can kill you dead very fast.
Unfortunately (or fortunately):
a) Most DVTs are mild and virtually asymptomatic, resolving spontaneously with no sequelae.
b) There is little correlation between the clinical severity of the initial DVT and the chances of a life threatening PE. In fact, most fatal PEs seem to occur after mild and un-noticed DVTs rather than big obvious ones.
c) Most PEs are minor and asyptomatic and go undiagnosed and un-noticed.
Perhaps 1/100 is noticed and 1/1000 is fatal.
DVTs/PEs are a significant problem in hospitals, mainly because few of us will ever forget those patients of ours who (after surgery/trauma ranging from the trivial to the severe) unexpectedly dropped dead from a massive PE.
Much attention has been given to preventing DVTs/PE, ranging from aspirin to heparin to early mobilisation to compression stockings etc., etc.
We have a rough idea which patients are most at risk (obese, cancer, immobile, pelvic surgery) and take precautions. Unfortunately there is still considerable controversy as to how effective these precautions are, with some quoting studies one way and some another.
Unfortunately, these days the matter is more legal than science driven.
Patients tend to receive anti-thromboembolism prophylaxis more on the basis of heading off lawsuits than on firm scientific grounds. I for instance, will use appropriate prophylaxis for at risk patients, but (having had a couple die in spite of ALL measures) feel in my heart of hearts that if it's going to happen then it's going to happen.
So the issue of passenger leg-room will probably (like so many issues in our society) become driven by lawyers and the third estate rather than by proper science. Airlines will compute a cost/benefit equation which relates cost of possibly lost (or more likely, conceded uncontested) lawsuits to cost of increasing seat separation and come out with an appropriate number.
Increased airline costs will simply be passed back to the pax, with a microcopic individual medical benefit. OK by me, if that is what society wants.
As for the Norwegian study, I do not doubt it's findings for a minute. Whether an increase in levels of compounds associated with blood clotting translates into a real increased risk of DVT is something else.
I agree wholeheartedly that we need further studies (doesn't everything?), but current evidence really does not point towards airline passenger DVTs being a major epidemiological phenomenon.
I'm sorry that you interpret my thoughts based on current evidence as being a sign of preconceived ideas. I am just as interested and concerned about the truth as you are - there are, after all, my patients! I hope that we are not getting into a situation where professionals have to say "Yessir nossir!" to any crusades that the press takes up for fear of being labelled obstructive and reactionary and being publicly pilloried.
Cheers
Mac
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Thanks for the friendly reply. We seem to be close to agreement, except on the perception of risk and the cost/benefeit of doing things about it. I must admit that as seat pitches become ever more cramped and as airlines tolerate lower and lower air quality and pressurisation levels (sometimes, I suspect, in a quite deliberate attempt to immobilise pax, who are easier to manage in their seats) I become more and more concerned.
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JN - cramped seat pitches bring to mind concerns about emergency evacuations esp. after Singapore. This is really almost another thread, but what are the regs. about this?
Lower and lower air quality - I know there was a thread about saving fuel by turning packs off - more info. pls.
Pressurisation levels - ?
These sound like more germane concerns - suggest that you start new threads as appropriate.
Cheers - Mac
Lower and lower air quality - I know there was a thread about saving fuel by turning packs off - more info. pls.
Pressurisation levels - ?
These sound like more germane concerns - suggest that you start new threads as appropriate.
Cheers - Mac
Guest
Posts: n/a
Mac.
I think all of these (and good point about seat pitch versus 'evacuability') are symptoms of corporate greed over-coming the carriers' duty of care to their customers. The ironic thing is that all bite hardest on long range routes, often where competition is least fierce and where excessive profits are already being made.
I think all of these (and good point about seat pitch versus 'evacuability') are symptoms of corporate greed over-coming the carriers' duty of care to their customers. The ironic thing is that all bite hardest on long range routes, often where competition is least fierce and where excessive profits are already being made.
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As a pilot (and passenger at times) with 38 years flying experience, and a possible contender for DVT, as I have been airborne for many a 10-14 hour flight, I have to counter some of the accusations and illogical comments made by the likes of BigSeat and Jackonicko.
Bigseat
You state, “at no stage do airlines inform passengers of the health risks associated with flying, and that is where the difficulty lies.”
Good God man, are you wanting “this flight could kill you” stamped on your ticket ?
Or “BEWARE you have a 99.999999% chance of walking away from this aircraft without a scratch”.
Does the manufacturer of your car inform you of the health risks involved with driving his car, or the passenger miles/fatal accident/year using the model you bought ?
Does the maker of your kitchen inform you of the health risks of cooking a meal whilst surrounded by his wares/other utensils ?
What about a label on your chip pan ( I assume you have one) stating,
“There have been 530 people killed in the UK due to chip pan fires in 1998 – be careful please” ?
I got a letter from SAGA (yes I’m over 50 !) the other day which informed me, “8 MILLION people (UK) require hospital treatment as a result of an accident at home, in the garden, on the road or at work”. Maybe that statement puts into sharp perspective this fanatical and foundless focus of DVT whilst flying in an economy class seat.
Maybe where the true “difficulty” lies, is the public are not told of the health risks of getting out of bed, so we could avoid DVT almost completely. What are airlines playing at !!!
Perhaps you want airlines to monitor their passengers AFTER they leave the aircraft to make sure DVT does not hit them, until “some time has elapsed”.
Maybe the rail operators do this already, seeing as a packed train could trigger DVT ? “Certain types of patients” will more than likely fall prey to DVT at some point in their life’s; is it because airlines are an easy touch for compensation that DVT is now the targeted hot potato ?
I’m sorry if this post is coming across as a very cynical view and biased, but of the MILLIONS that fly every year very, very few suffer any ill effects what so ever. The worst common ailment perhaps is jet-lag.
If you pay more attention trying to highlight killer diseases to those stuck on the ground than trying to screw airlines into believing they are responsible for contributing to DVT your energies would be worthwhile, instead of all that bloody nonsense about red or black boxes. Another area you could do well to attend to is your grammar dear boy ! “Their is a box….” Incorrect use of “their”.
I cannot afford to meddle with mind bending theory rubbish too much, and like the good doctors on this thread, I will stick to REAL scientific and medical evidence. I can handle that.
Jackonicko
Whilst we were all jerked back into your real world of, “a low pressure environment, lack of leg movement/exercise, poor quality air, dehydration are all contributory factors” I would challenge each point you make there !
Are you talking about modern flying ?
The “low pressure” you are talking about keeps you alive and warm, and keeps you as well as you were before you walked on the aircraft.
If you were ill, or harbouring some ailment prior your flight, then don’t fly….nobody is forcing you.
The “lack of leg movement” is as much your fault for not getting your bum off the seat and having a wander about; you are not tied in or handcuffed you know - there is no extra charge for taking a walk up and down the aisle.
The lack of “exercise” is a bit thick; 99% of people do not take proper “exercise” anyway, never mind having facilities for such “exercise” on an aircraft. I’m sure there are some good books you can buy on seated exercise manoeuvres.
If it’s more leg room you are really after, then buy a seat in the class which gives you the leg-room you want. You pay for what you get.
How much leg movement/exercise area does your car give you ? Do you spend more time in your car than on an aircraft ?
“Dehydration” is self induced - if you do not drink, what do you expect ? Does the airline you are talking about not give you a cup of tea or coffee, or a glass of water every time you ask for one ? Be prepared is a good old motto.
Whilst airlines are in a business and not running a charity organisation, then the needs of the passenger and the business will be met appropriately, and in that regard, “some sensible precautions (like giving pax more leg room)” have indeed been made…there are BIG seats in BIG areas in First Class….in fact you can have a BED if you want !
Virgin don’t even call it First Class. Sure it costs money, but if you want all the comforts of home, then you have to pay for them if you travel by air. Likewise with your choice of hotel.
Should I mention your car ? Electric windows/air conditioning/twin air bags/side impact protection/CD player, and hooks in the back for your jacket……Perhaps not !
So airlines have been “sensible” and have proved before now it is, “not beyond either the wit or the pockets of major airlines on the longer-range routes” to supply goods and services which are appropriate.
Maybe this, “open-mind medicine might also be of use” to passengers who have yet to sample what others have experienced, and not suffered DVT during their extremely limited exposure to these facilities.
There is a “risk and the cost/benefeit (sic) of doing things” in all walks of life, and I think… in fact I know…. current major western carriers have proved adequately they have that balance right.
I cannot agree with you that, “seat pitches become ever more cramped”. What airlines are you talking about ? Have you the before and after figures ?
If you want to hire a jumbo for yourself with all the space you could ever want, then pay the price and stop moaning about seat-pitch.
If you want to get to New York and have LOTS of leg room, air and water, take a ship. If you are in a hurry, fly. Mind you, there are other things to moan about during a sea voyage no doubt…..Oh! that salty smell in the air.
I cannot believe you when you say, “as airlines tolerate lower and lower air quality and pressurisation levels”.
In case you had not noticed, more and more prohibit that repulsive habit of smoking. The quality of cabin air, when matched with that of a restaurant which allows smoking, fairs very favourably I would strongly suggest.
It is just not in an airlines interest to “lower and lower air quality” - when did you last see a foggy haze of noxious fumes in the cabin ? When did you last walk down the streets of London during rush hour – that’s low quality air my boy !
As for your strange “pressurisation levels” jibe, I can tell you air pressure within a cabin is kept as near as possible to MSLP as the airframe will allow. Even at high cruise levels, the cabin pressure is equivalent to being up a 7500/8000 foot mountain, and you have not strained your body climbing it either.
The silly and presumably humorous intent in your statement, “sometimes, I suspect, in a quite deliberate attempt to immobilise pax, who are easier to manage in their seats, I become more and more concerned” is taking things too far.
The management of 200/300/400 passengers in a confined space is an organisation task around their needs for sociability and feeding routine, not to mention the proximity of “conveniences”.
The only thing deliberate is attempting to keep them safe for the period of “duty of care” and has little to do with “corporate greed” - we leave that to the fat cats who run Utility companies and the like. Will I mention the “Dome” ? No… better not.
If your train is cancelled due to a technical failure, does the operator give you a hot meal then put you up in a hotel for the night – bussing you back and forward at no cost ? The lengths to which an airline is willing to go to under their “duty of care” surpasses all other transport mediums - unless you can prove to me otherwise ?
Getting back to facts about DVT and risk exposure whilst flying as an airline passenger (presumably paying the lowest airfare) is absolutely minuscule - such cases highlighted in the popular press by the search for a “good story” by airline ‘knockers’ are not worth the candle towards proving DVT is a positive danger whilst flying long-haul.
Pilots should be good candidates for a research study into DVT, seeing they fly longer (a lifetime) in a confined space in a pressurised tube for extended periods, yet I do not know one in my 38 years flying who has suffered such an ailment/attack, never mind it being attributed to flying.
As “Mac the Knife” pointed out so succinctly, Kraaijenhagen et al. and perhaps rather to their surprise and chagrin no evidence was found (it can be disappointing when nothing surfaces to support one's study!) perhaps says it all.
The Norwegian Study
I’m no doctor, but some of the methods/descriptions used do NOT simulate a typical airliner under normal operating conditions.
For instance, the “hypobaric chamber” was capable of reducing pressure equivalent to 18,040 feet (50.7kPa) – if you were in an aircraft’s cabin with THAT pressure…..then there’s something seriously wrong !
They were “exposed to 76 kPa within 10 minutes” - this rate of change of pressure is too fast, and does NOT occur regularly under normal operating conditions. A typical airliner would take 20 minutes to climb (that’s twice as long before being exposed) to its cruise level equivalent to that 76 kPa as ATC seldom give a continuous climb, and if it’s a long range flight, sea level to max cruise would be at best 2000’/min so it would take 18.5 minutes roughly.
So this sudden exposure only taking 10 minutes would certainly mask results.
Each “exposure” normally lasted 8 hours, but they did not say how long the “descent” took. If they took the same time to ‘come down’ as they took to go up, then again any results do not match a typical flight !!
They also say, after 8 hours eight males returned to “baseline level” whilst the other 8 “participated in another high altitude experiment”. This would suggest another RAPID climb (that 10 minutes again) which again does NOT replicate an airliner climb to altitude and a slow reduction in ambient pressure.
The researchers may have shot themselves in the foot by using the phrase, “volunteers who were suddenly exposed to a hypobaric environment”. Airline passengers are NOT suddenly exposed to anything.
From a cabin altitude of 76 kPa ( 7872’
down to MSL an airliner takes about 20 minutes and sometimes longer.
The rate of change of ambient pressures to the body is just as important that what happens within as a result.
An explosive decompression is more traumatising than a slow decompression – needless to say !
The doctors conducting this very limited experiment which could be said barely related to normal airline ops admit, “Despite the lack of an adequate control group at normal atmospheric, our study suggests that RAPID exposure to an air pressure encountered in aeroplane cabins activates coagulation”.
On a similar footing, a diver RAPIDLY coming from depth to the surface faces the “bends” - so what does these rapid exposures to simulated airline passengers count for ?
Would all those haemostasis readings taken and catalogued be more valid and relevant if the volunteers were exposed to climb and descents that took twice as long ?
As I said before, I’m no doctor, but I would ask the same question as “Mac the Knife”…….
“ Whether an increase in levels of compounds associated with blood clotting translates into a real increased risk of DVT is something else”……..with the added twist, “is your ‘subject’ one who is at risk already because of his genetic make-up or a lingering, covert, disease that is conducive to DVT in a contrived environment.
Bigseat
You state, “at no stage do airlines inform passengers of the health risks associated with flying, and that is where the difficulty lies.”
Good God man, are you wanting “this flight could kill you” stamped on your ticket ?
Or “BEWARE you have a 99.999999% chance of walking away from this aircraft without a scratch”.
Does the manufacturer of your car inform you of the health risks involved with driving his car, or the passenger miles/fatal accident/year using the model you bought ?
Does the maker of your kitchen inform you of the health risks of cooking a meal whilst surrounded by his wares/other utensils ?
What about a label on your chip pan ( I assume you have one) stating,
“There have been 530 people killed in the UK due to chip pan fires in 1998 – be careful please” ?
I got a letter from SAGA (yes I’m over 50 !) the other day which informed me, “8 MILLION people (UK) require hospital treatment as a result of an accident at home, in the garden, on the road or at work”. Maybe that statement puts into sharp perspective this fanatical and foundless focus of DVT whilst flying in an economy class seat.
Maybe where the true “difficulty” lies, is the public are not told of the health risks of getting out of bed, so we could avoid DVT almost completely. What are airlines playing at !!!
Perhaps you want airlines to monitor their passengers AFTER they leave the aircraft to make sure DVT does not hit them, until “some time has elapsed”.
Maybe the rail operators do this already, seeing as a packed train could trigger DVT ? “Certain types of patients” will more than likely fall prey to DVT at some point in their life’s; is it because airlines are an easy touch for compensation that DVT is now the targeted hot potato ?
I’m sorry if this post is coming across as a very cynical view and biased, but of the MILLIONS that fly every year very, very few suffer any ill effects what so ever. The worst common ailment perhaps is jet-lag.
If you pay more attention trying to highlight killer diseases to those stuck on the ground than trying to screw airlines into believing they are responsible for contributing to DVT your energies would be worthwhile, instead of all that bloody nonsense about red or black boxes. Another area you could do well to attend to is your grammar dear boy ! “Their is a box….” Incorrect use of “their”.
I cannot afford to meddle with mind bending theory rubbish too much, and like the good doctors on this thread, I will stick to REAL scientific and medical evidence. I can handle that.
Jackonicko
Whilst we were all jerked back into your real world of, “a low pressure environment, lack of leg movement/exercise, poor quality air, dehydration are all contributory factors” I would challenge each point you make there !
Are you talking about modern flying ?
The “low pressure” you are talking about keeps you alive and warm, and keeps you as well as you were before you walked on the aircraft.
If you were ill, or harbouring some ailment prior your flight, then don’t fly….nobody is forcing you.
The “lack of leg movement” is as much your fault for not getting your bum off the seat and having a wander about; you are not tied in or handcuffed you know - there is no extra charge for taking a walk up and down the aisle.
The lack of “exercise” is a bit thick; 99% of people do not take proper “exercise” anyway, never mind having facilities for such “exercise” on an aircraft. I’m sure there are some good books you can buy on seated exercise manoeuvres.
If it’s more leg room you are really after, then buy a seat in the class which gives you the leg-room you want. You pay for what you get.
How much leg movement/exercise area does your car give you ? Do you spend more time in your car than on an aircraft ?
“Dehydration” is self induced - if you do not drink, what do you expect ? Does the airline you are talking about not give you a cup of tea or coffee, or a glass of water every time you ask for one ? Be prepared is a good old motto.
Whilst airlines are in a business and not running a charity organisation, then the needs of the passenger and the business will be met appropriately, and in that regard, “some sensible precautions (like giving pax more leg room)” have indeed been made…there are BIG seats in BIG areas in First Class….in fact you can have a BED if you want !
Virgin don’t even call it First Class. Sure it costs money, but if you want all the comforts of home, then you have to pay for them if you travel by air. Likewise with your choice of hotel.
Should I mention your car ? Electric windows/air conditioning/twin air bags/side impact protection/CD player, and hooks in the back for your jacket……Perhaps not !
So airlines have been “sensible” and have proved before now it is, “not beyond either the wit or the pockets of major airlines on the longer-range routes” to supply goods and services which are appropriate.
Maybe this, “open-mind medicine might also be of use” to passengers who have yet to sample what others have experienced, and not suffered DVT during their extremely limited exposure to these facilities.
There is a “risk and the cost/benefeit (sic) of doing things” in all walks of life, and I think… in fact I know…. current major western carriers have proved adequately they have that balance right.
I cannot agree with you that, “seat pitches become ever more cramped”. What airlines are you talking about ? Have you the before and after figures ?
If you want to hire a jumbo for yourself with all the space you could ever want, then pay the price and stop moaning about seat-pitch.
If you want to get to New York and have LOTS of leg room, air and water, take a ship. If you are in a hurry, fly. Mind you, there are other things to moan about during a sea voyage no doubt…..Oh! that salty smell in the air.
I cannot believe you when you say, “as airlines tolerate lower and lower air quality and pressurisation levels”.
In case you had not noticed, more and more prohibit that repulsive habit of smoking. The quality of cabin air, when matched with that of a restaurant which allows smoking, fairs very favourably I would strongly suggest.
It is just not in an airlines interest to “lower and lower air quality” - when did you last see a foggy haze of noxious fumes in the cabin ? When did you last walk down the streets of London during rush hour – that’s low quality air my boy !
As for your strange “pressurisation levels” jibe, I can tell you air pressure within a cabin is kept as near as possible to MSLP as the airframe will allow. Even at high cruise levels, the cabin pressure is equivalent to being up a 7500/8000 foot mountain, and you have not strained your body climbing it either.
The silly and presumably humorous intent in your statement, “sometimes, I suspect, in a quite deliberate attempt to immobilise pax, who are easier to manage in their seats, I become more and more concerned” is taking things too far.
The management of 200/300/400 passengers in a confined space is an organisation task around their needs for sociability and feeding routine, not to mention the proximity of “conveniences”.
The only thing deliberate is attempting to keep them safe for the period of “duty of care” and has little to do with “corporate greed” - we leave that to the fat cats who run Utility companies and the like. Will I mention the “Dome” ? No… better not.
If your train is cancelled due to a technical failure, does the operator give you a hot meal then put you up in a hotel for the night – bussing you back and forward at no cost ? The lengths to which an airline is willing to go to under their “duty of care” surpasses all other transport mediums - unless you can prove to me otherwise ?
Getting back to facts about DVT and risk exposure whilst flying as an airline passenger (presumably paying the lowest airfare) is absolutely minuscule - such cases highlighted in the popular press by the search for a “good story” by airline ‘knockers’ are not worth the candle towards proving DVT is a positive danger whilst flying long-haul.
Pilots should be good candidates for a research study into DVT, seeing they fly longer (a lifetime) in a confined space in a pressurised tube for extended periods, yet I do not know one in my 38 years flying who has suffered such an ailment/attack, never mind it being attributed to flying.
As “Mac the Knife” pointed out so succinctly, Kraaijenhagen et al. and perhaps rather to their surprise and chagrin no evidence was found (it can be disappointing when nothing surfaces to support one's study!) perhaps says it all.
The Norwegian Study
I’m no doctor, but some of the methods/descriptions used do NOT simulate a typical airliner under normal operating conditions.
For instance, the “hypobaric chamber” was capable of reducing pressure equivalent to 18,040 feet (50.7kPa) – if you were in an aircraft’s cabin with THAT pressure…..then there’s something seriously wrong !
They were “exposed to 76 kPa within 10 minutes” - this rate of change of pressure is too fast, and does NOT occur regularly under normal operating conditions. A typical airliner would take 20 minutes to climb (that’s twice as long before being exposed) to its cruise level equivalent to that 76 kPa as ATC seldom give a continuous climb, and if it’s a long range flight, sea level to max cruise would be at best 2000’/min so it would take 18.5 minutes roughly.
So this sudden exposure only taking 10 minutes would certainly mask results.
Each “exposure” normally lasted 8 hours, but they did not say how long the “descent” took. If they took the same time to ‘come down’ as they took to go up, then again any results do not match a typical flight !!
They also say, after 8 hours eight males returned to “baseline level” whilst the other 8 “participated in another high altitude experiment”. This would suggest another RAPID climb (that 10 minutes again) which again does NOT replicate an airliner climb to altitude and a slow reduction in ambient pressure.
The researchers may have shot themselves in the foot by using the phrase, “volunteers who were suddenly exposed to a hypobaric environment”. Airline passengers are NOT suddenly exposed to anything.
From a cabin altitude of 76 kPa ( 7872’
down to MSL an airliner takes about 20 minutes and sometimes longer. The rate of change of ambient pressures to the body is just as important that what happens within as a result.
An explosive decompression is more traumatising than a slow decompression – needless to say !
The doctors conducting this very limited experiment which could be said barely related to normal airline ops admit, “Despite the lack of an adequate control group at normal atmospheric, our study suggests that RAPID exposure to an air pressure encountered in aeroplane cabins activates coagulation”.
On a similar footing, a diver RAPIDLY coming from depth to the surface faces the “bends” - so what does these rapid exposures to simulated airline passengers count for ?
Would all those haemostasis readings taken and catalogued be more valid and relevant if the volunteers were exposed to climb and descents that took twice as long ?
As I said before, I’m no doctor, but I would ask the same question as “Mac the Knife”…….
“ Whether an increase in levels of compounds associated with blood clotting translates into a real increased risk of DVT is something else”……..with the added twist, “is your ‘subject’ one who is at risk already because of his genetic make-up or a lingering, covert, disease that is conducive to DVT in a contrived environment.
Guest
Posts: n/a
I'll ignore your deliberately provocative and sneering tone, as long as you don't start 'Dear Boying' again.
I'm not unusually tall, but have often found myself with inadequate leg-room in economy on long-haul flights (I'd expect it short-haul or charter), having to cant my legs into the aisle, or having to sit diagonally to avoid bashing my knees on the seat in front.
You're being either disingenuous or stupid if you seriously think it's possible or practical to walk about when you want, even if you've been lucky enough to get an aisle seat. This is discouraged by the cabin crew, who want you quiet, predictable and docile. Most of us are insufficiently arrogant or aggressive to go ahead and do what we want, and most of us don't like to 'make a fuss'.
And I'd be happy to pay a little more for human conditions, but don't necessarily want (and can't always afford) Business Class. We're talking about expecting a reasonable, tolerable degree of comfort and safety when we travel, not luxury. The last time I flew to the West Coast with BA, I had less space than I've ever had in a bus, train, or even the back seat of many cars, and that simply isn't good enough. On that particular route (Phoenix) there is no competition, and £520 return should have brought me something closer to a proper standard.
If they can afford to pay current salary levels, they can afford to give my knees an inch extra, I'm sure.
I'm not unusually tall, but have often found myself with inadequate leg-room in economy on long-haul flights (I'd expect it short-haul or charter), having to cant my legs into the aisle, or having to sit diagonally to avoid bashing my knees on the seat in front.
You're being either disingenuous or stupid if you seriously think it's possible or practical to walk about when you want, even if you've been lucky enough to get an aisle seat. This is discouraged by the cabin crew, who want you quiet, predictable and docile. Most of us are insufficiently arrogant or aggressive to go ahead and do what we want, and most of us don't like to 'make a fuss'.
And I'd be happy to pay a little more for human conditions, but don't necessarily want (and can't always afford) Business Class. We're talking about expecting a reasonable, tolerable degree of comfort and safety when we travel, not luxury. The last time I flew to the West Coast with BA, I had less space than I've ever had in a bus, train, or even the back seat of many cars, and that simply isn't good enough. On that particular route (Phoenix) there is no competition, and £520 return should have brought me something closer to a proper standard.
If they can afford to pay current salary levels, they can afford to give my knees an inch extra, I'm sure.
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Hmmm...I can see that this one is going to run and run...
TG - if I may correct you without weakening your case, bed is a bad place to be as far as DVTs are concerned - otherwise spot on (tho' clambering out of your economy seat for a stroll can be a major excursion and is not exactly encouraged by cabin crew).
My better 'alf rather sourly comments that you are so bl**dy uncomfortable most of the time that you can't help fidgeting and giving your legs some exercise...
And on that note....
TG - if I may correct you without weakening your case, bed is a bad place to be as far as DVTs are concerned - otherwise spot on (tho' clambering out of your economy seat for a stroll can be a major excursion and is not exactly encouraged by cabin crew).
My better 'alf rather sourly comments that you are so bl**dy uncomfortable most of the time that you can't help fidgeting and giving your legs some exercise...
And on that note....
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In a report entitled "Could these seats be the death of you?" the Daily Telegraph said that:
"One in 10 air passengers is at risk of suffering DVT - blood clotting that is potentially fatal. But the danger, as Carole Cadwalladr reports, is an avoidable one."
THERE'S not much left when the news moves on. A fortnight ago the story of how Emma Christoffersen, a 28-year-old "bride-to-be", collapsed and died minutes after she stepped off the plane home from "the holiday of a lifetime" briefly caught the nation's attention. Young and pretty, she was the perfect newspaper victim; her frozen smile from the family snapshot reproduced in grainy black and white - the familiar mark of one who has died in circumstances that are always tragic and usually avoidable.
You may think you've read this story before, but you haven't. Emma's death has more or less been consigned to the status of a freak accident. But it wasn't. The immediate cause of death was a pulmonary embolism, or blood clot, on the lungs, brought on by DVT - deep-vein thrombosis. And the cause of the DVT, said the consultant, was prolonged immobility on the long-haul flight.
For a couple of days, stories about DVT filled the newspapers and the airwaves. And then the news moved on. All that is left is her family's memories, a wilting floral tribute and a book of remembrance in a corner of Newport's Marks & Spencer, where she worked. But the key to this story lies in the newspaper portrait: she died in circumstances that were tragic and that were avoidable.
Flying-related DVT may have only just hit the headlines but this does not mean that it has recently been discovered - far from it. But the difficulty in tracking cases, the lack of research into it, the absence of any recorded figures has enabled the airlines to avoid the issue.
Emma's death was not a freak accident; four of the specialists we contacted claim that on average they see two cases of flying-related DVT a week we have evidence of three people, living within 50 miles of each other, who have developed DVT after long-haul flights in the past three months. Two of them died. One of them, David Billington, survived. None of them could be considered high-risk cases; their deaths have not been investigated. No one has any clearer idea why they developed it, whether the design of the seats or the cabin air is a contributory factor or not. The airlines have accused journalists of "scaremongering". This is not scaremongering; it is scary.
Two days after Emma's death was reported, another story appeared in the newspapers. Research published in The Lancet, it was claimed, showed that there was no link between flying and blood clots. The timing could not have been worse. The report has been systematically slated by every scientist working on DVT in Britain yet it provided the airlines with another excuse not to investigate further, to ignore what is clearly mounting evidence.
By contrast, preliminary results of the first "prospective" (ie, examining people before and after) clinical study into DVT among airline passengers, obtained by The Daily Telegraph, indicate that one in 10 developed clots after long-haul flights.
John Thomas, 30, lived 30 miles from Emma Christoffersen. As a policeman, he had just undergone a rigorous fitness examination and, says his mother Ada, had "not just passed with flying colours but had been complimented on his strength". With his new wife, Sarah, he had an uncomfortable 11-hour flight home from Hawaii with American Airlines. "He said that he felt very cramped on the plane, his legs ached and he felt very thirsty," says Mrs Thomas. Back at his home in Cowbridge, Vale of Glamorgan, he started feeling under the weather.
Two weeks after their return from Hawaii, his wife found him dead. The cause of death was a pulmonary embolism, which in the opinion of the pathologist at the Princess of Wales hospital, Bridgend, had been caused by DVT brought on by the long-haul flight and the sub-tropical climate, which had left him dehydrated.
Because John had been such a fit man, doctors suggested the whole family be tested for a predisposition to DVT. The tests were negative. The next day the family read about Emma Christoffersen. "We just felt so guilty," says Mrs Thomas. "We thought maybe if we had told the newspapers about what happened to John she might have known, she might still be alive."
Twenty miles from Emma's home in Bristol, David Billington, a fit and healthy 48-year-old, also found himself reading about her death in the newspaper on the morning of October 23. Like Emma, he had just returned from Australia and had cramps in his legs. "I was on almost exactly the same route, travelling back to Britain via Hong Kong. And on Sunday night I started getting excruciating pains in my legs. When I read the story about Emma I started wondering if that was what I had, but I thought, 'Don't be so stupid, it's just cramp.' "
He flew to Zurich the next day to attend a business meeting as planned, but when he returned the pain had worsened. He called the local health helpline and was advised to go to hospital. He had DVT. In the opinion of the haemotologist, it had been brought on by the long-haul flight. "I was incredibly lucky. The riskiest thing I could have done was to go on another flight. If the clot had broken away from my leg I would probably be dead."
It is not idle speculation that the deaths of Emma Christoffersen and John Thomas and the DVT suffered by David Billington might have been brought about by long-haul flights. That is the medical diagnosis. But because pulmonary emboli are regarded as "natural" causes of death, there have been no inquests. There are no statistics. The airlines have never been summoned to produce evidence. And there have been no inquiries.
In the front room of their terraced house outside Newport, Emma's parents and her fiancé have the letter they were sent by Qantas. John, Emma's father, shakes as he hands it over. He is not tearful, he is furious. "On the news we watched the Qantas spokesman saying that they wanted to get in touch with us . . . And the only thing we've heard from them is this . . ."
This is a letter that runs to three paragraphs and ends with the sentence: "Regrettably we know little of the details involved in Emma's death. If you wish to speak directly with our Aviation Medical Department, please let me know."
"You would think that they might want to know why Emma died," says Ruth Christoffersen, Emma's mother. But since Emma collapsed 50 yards from the door of its plane, Qantas is under no legal obligation to record, let alone investigate the matter. Heathrow keeps no records of such incidents. Neither does the Civil Aviation Authority.
Tim Stuart, Emma's fiancé, tells the next part of the story. "It was a completely normal flight. She had no pains, no symptoms. She and Rhian were rushing because they were late for the bus. They were laughing and joking At the end of the walkway from the plane, she said to Rhian, 'Oh I need to sit down. I'm not feeling so good.' And then she passed out."
Emma did not regain consciousness. She was taken to Ashford Hospital, where she was pronounced dead. "When we asked the ward sister why, she said that she couldn't be certain, but she was sure it was DVT from the flight. She said that she sees two to three cases from Heathrow a week. What was unusual was that it had happened to someone as young as Emma."
Camera crews from CNN and ABC arrived in Newport. Reporters from Holland, Australia and Germany were on the phone.
Most victims of DVT don't die at the airport. Death usually occurs several weeks later. Or even, as Professor Kevin Burnand, professor of surgery at Guy's, King's and St Thomas's hospitals, suggests, years later. "Many people don't realise they've had DVT until they end up in the hospital years later with an ulcer in their legs, or until they drop down dead from a pulmonary embolism."
Even so, Professor Burnand estimates that he sees two people a week who have developed DVT after a long-haul flight, as does Professor John Scurr, consultant surgeon at Middlesex Hospital.
John Belstead, Accident and Emergency specialist at Ashford Hospital, says that on average he sees one passenger from Heathrow a month who has a pulmonary embolism. And, on average, they are dead. "The point is that we only see the really serious cases and that means that they are usually dead when they get here. Unless you are seriously ill, you are just going to go home. The cases are dispersed all over the country, hence the problem in knowing what the numbers are." On further questioning, it becomes evident that his "one-a-month" figure only relates to fit, healthy, young people. Older passengers, or those in a higher-risk category (which includes, he says, being on the Pill) are not included in this figure. Of them, he sees one every 10 days.
Emma had not heard of DVT. Nor had John Thomas. He exhibited symptoms for two weeks but did not recognise them. "How are you supposed to know about it if the airline doesn't tell you?" demands Mrs Christoffersen. "We've been talking to medical people and they all know about DVT. Their families all know. The ward sister told us that she takes aspirin for a week before a flight. The airlines have a moral duty to tell people of the risks. How are you supposed to know that you can be killed by just sitting on an aeroplane? What can be the harm in that?"
The harm, according to preliminary research conducted by Professor Scurr, is that you have a one in 10 chance of developing a clot. He has enlisted the help of 200 volunteers, all over 50, have no previous history of clotting, and who would be flying for more than eight hours to their destination and the same back again. "It is a pure group. We have excluded anybody who might be considered high-risk. We scanned them before they went, and we are scanning them as they return. And some of them have come back with clots."
The results are still being analysed and will not be published in The Lancet for a month, but indications are that the problem could be greater than anyone envisaged.
"Most of these people are unaware that they have it. They don't necessarily have swollen legs. They don't have any symptoms. These are not necessarily big, life-threatening clots but we are getting some idea of how common it is. We don't want to scare people and we certainly don't want to discourage them from travelling. But we had no idea that it would be as high as 10 per cent. If it is as common as our research is suggesting, then we must think about giving advice. The bottom line is that there is a link between clotting and flying."
George Geroulakas, consultant vascular surgeon at Ealing Hospital (which, like Ashford, is in the Heathrow catchment area), is conducting another study on DVT risk factors and incidence. His preliminary results show that 10 per cent of all DVTs occur after long-haul flights.
The link between pulmonary emboli and prolonged periods of immobility was first noticed among people who sought refuge in air-raid shelters during the Blitz; the first suggestion that sitting immobile in an aeroplane could be a cause was published in 1992, in a paper that related anecdotal evidence from attending physicians.
More research has to be done. "The difficulty is one of funding," says Professor Scurr. "The airlines haven't been interested in drawing attention to a negative aspect of flying."
Professor Burnand, on the other hand, has the funding. Two years ago he was awarded a grant from the Occupational Health Institute to undertake the largest study of DVT among airline passengers ever attempted. He has the money, the nurses and the equipment. What he doesn't have is the passengers. "I have been down to British Airways countless times. I have sent them thousands of emails and they have faffed around. And Virgin has too, for that matter. The problem is that they don't believe it's in their interests. Our line has always been that we have to know what the numbers are."
Passengers who volunteered would be blood-tested immediately before they stepped on to the plane at Heathrow and immediately after stepping off it in Australia. "I have seen lots and lots of patients who have developed DVT after flying. Now, there may well be underlying factors but this is what we need to find out," says Professor Burnand.
The standard health advice is to drink water, walk around, move your legs. "The airlines have been saying that you should drink water," says Mrs Thomas, "and yet they serve up alcohol and tea and coffee - all the things you're not supposed to drink." The airlines, says Mrs Christoffersen, have a moral duty to warn people of the dangers of DVT. But the layout of their planes does not encourage passengers to follow their own good advice; their provision of beverages hardly promotes hydration; their efforts to investigate the causes of DVT have been underwhelming and their failure to co-operate with medical studies such as Professor Burnand's into the effects on actual passengers, is, under the circumstances, a shame.
Dr Richard Dawood, a travel medicine specialist, is even more critical of the airlines. This summer he gave evidence to an inquiry into air travel and health being conducted by a select committee of the House of Lords. Its findings will be published at the end of the month, and it is believed that they are likely to recommend action on the part of the airlines. "It is very clear that something needs to be done," says Dr Dawood. "And it is equally clear the airlines should not be left to police themselves. It is in their commercial interests to get away with what they can but it is not in the passengers' interests."
The airlines, says Dr Dawood, "have hidden behind semantics". DVT is not caused by flying but by sitting still, they say. "You can get it on a car journey or in the theatre," says a BA spokeswoman, "there's nothing to link it to flying." Few people tend to watch 10-hour plays, however, and the effects of cabin pressure, dehydration and types of seating have yet to be researched.
A Qantas spokesman says it has revamped its health information in its inflight magazine and audio programmes and next month is looking at producing video segments to play inflight. British Airways, again, says the information is in the inflight magazine and "on the website". It claims to have helped Dr Kesteven of the Freeman Hospital in Newcastle-upon-Tyne with his research, but as yet this has been limited to providing some information "on the lengths of flights etc"; no clinical study into actual passengers has been undertaken or scheduled.
Qantas says it is working with Griffiths University in Brisbane, and that it would like to investigate Emma's death further but is sensitive to the feelings of the relatives. Surprisingly perhaps, Britannia, a charter airline, is already doing more than both major airlines. It has started making cabin crew announcements during the flight, urging passengers to at least stand up occasionally and to move around when possible; and is sending all cabin crew on a DVT-awareness course.
Without knowing the precise causes of DVT and whether or not you are at risk, the only way to protect yourself is by being aware of its symptoms and its dangers. "John was an intelligent man," says Mrs Thomas. "And he didn't know about it. He had a degree in geology, a degree in law. If he got it wrong, then anybody can."
"We can't turn back the clock," says Mrs Christoffersen. "But had we known about DVT, had we known, I can guarantee you that it is 100 per cent certain Emma would be sitting here today."
* David Billington's name has been changed.
DVT and how to avoid it
What is DVT?
The blood in our legs is returned to the heart as a result of muscle contractions when we walk. Periods of immobility can cause a clot in the muscles of the lower leg - DVT.
And the symptoms?
Throbbing, or pain, in the leg; cramp or swelling or both. Having these does not necessarily mean you have DVT; but not having them doesn't necessarily mean you haven't got it.
What's the worst that can happen?
If the clot remains in the leg, it can be treated with blood-thinning drugs such as Warfarin. If it breaks free, it can travel to the lungs, the heart, the brain - with fatal consequences.
Why has it been called "economy-class syndrome"?
The term was coined by a scientist writing in The Lancet - who had also seen DVT in passengers from first and business class. There is no evidence that diminution in seat sizes has increased the number of cases. But no research has disproved the theory that cramped seating may make things worse.
Is the connection to long-haul flights proven?
The connection between DVT and immobility was first recognised in air-raid shelters during the Blitz. No one, not even the airlines, disputes that sitting in one position for a long time can cause DVT.
Is the risk any greater than going on a long car journey?
Few people drive for eight hours without stopping and car journeys are not necessarily dehydrating. The effects of cabin pressurisation are much debated, but dehydration has been shown to increase the likelihood of blood clotting.
Why don't airlines tell you this during safety announcements?
Because they don't have to. It is only in the past couple of years that they have admitted that passengers are contracting DVT after long-haul flights.
Are some people more at risk?
Yes. Those who smoke, take the Pill or HRT, who are pregnant, who have spent a few days lying in bed or who have a family history of blood clots. You may be prone to clots without realising it.
So, what should I do?
John Belstead, Dr Kesteven and Professor Scurr all take an aspirin (which thins the blood); Professor Burnand's wife wears elasticated stockings (which compress the veins). You must drink lots of water and move your legs regularly. Don't take a sleeping pill and stay in one position.
If your meal has been left on your tray for more than 45 minutes, making it impossible to leave your seat, complain.
"One in 10 air passengers is at risk of suffering DVT - blood clotting that is potentially fatal. But the danger, as Carole Cadwalladr reports, is an avoidable one."
THERE'S not much left when the news moves on. A fortnight ago the story of how Emma Christoffersen, a 28-year-old "bride-to-be", collapsed and died minutes after she stepped off the plane home from "the holiday of a lifetime" briefly caught the nation's attention. Young and pretty, she was the perfect newspaper victim; her frozen smile from the family snapshot reproduced in grainy black and white - the familiar mark of one who has died in circumstances that are always tragic and usually avoidable.
You may think you've read this story before, but you haven't. Emma's death has more or less been consigned to the status of a freak accident. But it wasn't. The immediate cause of death was a pulmonary embolism, or blood clot, on the lungs, brought on by DVT - deep-vein thrombosis. And the cause of the DVT, said the consultant, was prolonged immobility on the long-haul flight.
For a couple of days, stories about DVT filled the newspapers and the airwaves. And then the news moved on. All that is left is her family's memories, a wilting floral tribute and a book of remembrance in a corner of Newport's Marks & Spencer, where she worked. But the key to this story lies in the newspaper portrait: she died in circumstances that were tragic and that were avoidable.
Flying-related DVT may have only just hit the headlines but this does not mean that it has recently been discovered - far from it. But the difficulty in tracking cases, the lack of research into it, the absence of any recorded figures has enabled the airlines to avoid the issue.
Emma's death was not a freak accident; four of the specialists we contacted claim that on average they see two cases of flying-related DVT a week we have evidence of three people, living within 50 miles of each other, who have developed DVT after long-haul flights in the past three months. Two of them died. One of them, David Billington, survived. None of them could be considered high-risk cases; their deaths have not been investigated. No one has any clearer idea why they developed it, whether the design of the seats or the cabin air is a contributory factor or not. The airlines have accused journalists of "scaremongering". This is not scaremongering; it is scary.
Two days after Emma's death was reported, another story appeared in the newspapers. Research published in The Lancet, it was claimed, showed that there was no link between flying and blood clots. The timing could not have been worse. The report has been systematically slated by every scientist working on DVT in Britain yet it provided the airlines with another excuse not to investigate further, to ignore what is clearly mounting evidence.
By contrast, preliminary results of the first "prospective" (ie, examining people before and after) clinical study into DVT among airline passengers, obtained by The Daily Telegraph, indicate that one in 10 developed clots after long-haul flights.
John Thomas, 30, lived 30 miles from Emma Christoffersen. As a policeman, he had just undergone a rigorous fitness examination and, says his mother Ada, had "not just passed with flying colours but had been complimented on his strength". With his new wife, Sarah, he had an uncomfortable 11-hour flight home from Hawaii with American Airlines. "He said that he felt very cramped on the plane, his legs ached and he felt very thirsty," says Mrs Thomas. Back at his home in Cowbridge, Vale of Glamorgan, he started feeling under the weather.
Two weeks after their return from Hawaii, his wife found him dead. The cause of death was a pulmonary embolism, which in the opinion of the pathologist at the Princess of Wales hospital, Bridgend, had been caused by DVT brought on by the long-haul flight and the sub-tropical climate, which had left him dehydrated.
Because John had been such a fit man, doctors suggested the whole family be tested for a predisposition to DVT. The tests were negative. The next day the family read about Emma Christoffersen. "We just felt so guilty," says Mrs Thomas. "We thought maybe if we had told the newspapers about what happened to John she might have known, she might still be alive."
Twenty miles from Emma's home in Bristol, David Billington, a fit and healthy 48-year-old, also found himself reading about her death in the newspaper on the morning of October 23. Like Emma, he had just returned from Australia and had cramps in his legs. "I was on almost exactly the same route, travelling back to Britain via Hong Kong. And on Sunday night I started getting excruciating pains in my legs. When I read the story about Emma I started wondering if that was what I had, but I thought, 'Don't be so stupid, it's just cramp.' "
He flew to Zurich the next day to attend a business meeting as planned, but when he returned the pain had worsened. He called the local health helpline and was advised to go to hospital. He had DVT. In the opinion of the haemotologist, it had been brought on by the long-haul flight. "I was incredibly lucky. The riskiest thing I could have done was to go on another flight. If the clot had broken away from my leg I would probably be dead."
It is not idle speculation that the deaths of Emma Christoffersen and John Thomas and the DVT suffered by David Billington might have been brought about by long-haul flights. That is the medical diagnosis. But because pulmonary emboli are regarded as "natural" causes of death, there have been no inquests. There are no statistics. The airlines have never been summoned to produce evidence. And there have been no inquiries.
In the front room of their terraced house outside Newport, Emma's parents and her fiancé have the letter they were sent by Qantas. John, Emma's father, shakes as he hands it over. He is not tearful, he is furious. "On the news we watched the Qantas spokesman saying that they wanted to get in touch with us . . . And the only thing we've heard from them is this . . ."
This is a letter that runs to three paragraphs and ends with the sentence: "Regrettably we know little of the details involved in Emma's death. If you wish to speak directly with our Aviation Medical Department, please let me know."
"You would think that they might want to know why Emma died," says Ruth Christoffersen, Emma's mother. But since Emma collapsed 50 yards from the door of its plane, Qantas is under no legal obligation to record, let alone investigate the matter. Heathrow keeps no records of such incidents. Neither does the Civil Aviation Authority.
Tim Stuart, Emma's fiancé, tells the next part of the story. "It was a completely normal flight. She had no pains, no symptoms. She and Rhian were rushing because they were late for the bus. They were laughing and joking At the end of the walkway from the plane, she said to Rhian, 'Oh I need to sit down. I'm not feeling so good.' And then she passed out."
Emma did not regain consciousness. She was taken to Ashford Hospital, where she was pronounced dead. "When we asked the ward sister why, she said that she couldn't be certain, but she was sure it was DVT from the flight. She said that she sees two to three cases from Heathrow a week. What was unusual was that it had happened to someone as young as Emma."
Camera crews from CNN and ABC arrived in Newport. Reporters from Holland, Australia and Germany were on the phone.
Most victims of DVT don't die at the airport. Death usually occurs several weeks later. Or even, as Professor Kevin Burnand, professor of surgery at Guy's, King's and St Thomas's hospitals, suggests, years later. "Many people don't realise they've had DVT until they end up in the hospital years later with an ulcer in their legs, or until they drop down dead from a pulmonary embolism."
Even so, Professor Burnand estimates that he sees two people a week who have developed DVT after a long-haul flight, as does Professor John Scurr, consultant surgeon at Middlesex Hospital.
John Belstead, Accident and Emergency specialist at Ashford Hospital, says that on average he sees one passenger from Heathrow a month who has a pulmonary embolism. And, on average, they are dead. "The point is that we only see the really serious cases and that means that they are usually dead when they get here. Unless you are seriously ill, you are just going to go home. The cases are dispersed all over the country, hence the problem in knowing what the numbers are." On further questioning, it becomes evident that his "one-a-month" figure only relates to fit, healthy, young people. Older passengers, or those in a higher-risk category (which includes, he says, being on the Pill) are not included in this figure. Of them, he sees one every 10 days.
Emma had not heard of DVT. Nor had John Thomas. He exhibited symptoms for two weeks but did not recognise them. "How are you supposed to know about it if the airline doesn't tell you?" demands Mrs Christoffersen. "We've been talking to medical people and they all know about DVT. Their families all know. The ward sister told us that she takes aspirin for a week before a flight. The airlines have a moral duty to tell people of the risks. How are you supposed to know that you can be killed by just sitting on an aeroplane? What can be the harm in that?"
The harm, according to preliminary research conducted by Professor Scurr, is that you have a one in 10 chance of developing a clot. He has enlisted the help of 200 volunteers, all over 50, have no previous history of clotting, and who would be flying for more than eight hours to their destination and the same back again. "It is a pure group. We have excluded anybody who might be considered high-risk. We scanned them before they went, and we are scanning them as they return. And some of them have come back with clots."
The results are still being analysed and will not be published in The Lancet for a month, but indications are that the problem could be greater than anyone envisaged.
"Most of these people are unaware that they have it. They don't necessarily have swollen legs. They don't have any symptoms. These are not necessarily big, life-threatening clots but we are getting some idea of how common it is. We don't want to scare people and we certainly don't want to discourage them from travelling. But we had no idea that it would be as high as 10 per cent. If it is as common as our research is suggesting, then we must think about giving advice. The bottom line is that there is a link between clotting and flying."
George Geroulakas, consultant vascular surgeon at Ealing Hospital (which, like Ashford, is in the Heathrow catchment area), is conducting another study on DVT risk factors and incidence. His preliminary results show that 10 per cent of all DVTs occur after long-haul flights.
The link between pulmonary emboli and prolonged periods of immobility was first noticed among people who sought refuge in air-raid shelters during the Blitz; the first suggestion that sitting immobile in an aeroplane could be a cause was published in 1992, in a paper that related anecdotal evidence from attending physicians.
More research has to be done. "The difficulty is one of funding," says Professor Scurr. "The airlines haven't been interested in drawing attention to a negative aspect of flying."
Professor Burnand, on the other hand, has the funding. Two years ago he was awarded a grant from the Occupational Health Institute to undertake the largest study of DVT among airline passengers ever attempted. He has the money, the nurses and the equipment. What he doesn't have is the passengers. "I have been down to British Airways countless times. I have sent them thousands of emails and they have faffed around. And Virgin has too, for that matter. The problem is that they don't believe it's in their interests. Our line has always been that we have to know what the numbers are."
Passengers who volunteered would be blood-tested immediately before they stepped on to the plane at Heathrow and immediately after stepping off it in Australia. "I have seen lots and lots of patients who have developed DVT after flying. Now, there may well be underlying factors but this is what we need to find out," says Professor Burnand.
The standard health advice is to drink water, walk around, move your legs. "The airlines have been saying that you should drink water," says Mrs Thomas, "and yet they serve up alcohol and tea and coffee - all the things you're not supposed to drink." The airlines, says Mrs Christoffersen, have a moral duty to warn people of the dangers of DVT. But the layout of their planes does not encourage passengers to follow their own good advice; their provision of beverages hardly promotes hydration; their efforts to investigate the causes of DVT have been underwhelming and their failure to co-operate with medical studies such as Professor Burnand's into the effects on actual passengers, is, under the circumstances, a shame.
Dr Richard Dawood, a travel medicine specialist, is even more critical of the airlines. This summer he gave evidence to an inquiry into air travel and health being conducted by a select committee of the House of Lords. Its findings will be published at the end of the month, and it is believed that they are likely to recommend action on the part of the airlines. "It is very clear that something needs to be done," says Dr Dawood. "And it is equally clear the airlines should not be left to police themselves. It is in their commercial interests to get away with what they can but it is not in the passengers' interests."
The airlines, says Dr Dawood, "have hidden behind semantics". DVT is not caused by flying but by sitting still, they say. "You can get it on a car journey or in the theatre," says a BA spokeswoman, "there's nothing to link it to flying." Few people tend to watch 10-hour plays, however, and the effects of cabin pressure, dehydration and types of seating have yet to be researched.
A Qantas spokesman says it has revamped its health information in its inflight magazine and audio programmes and next month is looking at producing video segments to play inflight. British Airways, again, says the information is in the inflight magazine and "on the website". It claims to have helped Dr Kesteven of the Freeman Hospital in Newcastle-upon-Tyne with his research, but as yet this has been limited to providing some information "on the lengths of flights etc"; no clinical study into actual passengers has been undertaken or scheduled.
Qantas says it is working with Griffiths University in Brisbane, and that it would like to investigate Emma's death further but is sensitive to the feelings of the relatives. Surprisingly perhaps, Britannia, a charter airline, is already doing more than both major airlines. It has started making cabin crew announcements during the flight, urging passengers to at least stand up occasionally and to move around when possible; and is sending all cabin crew on a DVT-awareness course.
Without knowing the precise causes of DVT and whether or not you are at risk, the only way to protect yourself is by being aware of its symptoms and its dangers. "John was an intelligent man," says Mrs Thomas. "And he didn't know about it. He had a degree in geology, a degree in law. If he got it wrong, then anybody can."
"We can't turn back the clock," says Mrs Christoffersen. "But had we known about DVT, had we known, I can guarantee you that it is 100 per cent certain Emma would be sitting here today."
* David Billington's name has been changed.
DVT and how to avoid it
What is DVT?
The blood in our legs is returned to the heart as a result of muscle contractions when we walk. Periods of immobility can cause a clot in the muscles of the lower leg - DVT.
And the symptoms?
Throbbing, or pain, in the leg; cramp or swelling or both. Having these does not necessarily mean you have DVT; but not having them doesn't necessarily mean you haven't got it.
What's the worst that can happen?
If the clot remains in the leg, it can be treated with blood-thinning drugs such as Warfarin. If it breaks free, it can travel to the lungs, the heart, the brain - with fatal consequences.
Why has it been called "economy-class syndrome"?
The term was coined by a scientist writing in The Lancet - who had also seen DVT in passengers from first and business class. There is no evidence that diminution in seat sizes has increased the number of cases. But no research has disproved the theory that cramped seating may make things worse.
Is the connection to long-haul flights proven?
The connection between DVT and immobility was first recognised in air-raid shelters during the Blitz. No one, not even the airlines, disputes that sitting in one position for a long time can cause DVT.
Is the risk any greater than going on a long car journey?
Few people drive for eight hours without stopping and car journeys are not necessarily dehydrating. The effects of cabin pressurisation are much debated, but dehydration has been shown to increase the likelihood of blood clotting.
Why don't airlines tell you this during safety announcements?
Because they don't have to. It is only in the past couple of years that they have admitted that passengers are contracting DVT after long-haul flights.
Are some people more at risk?
Yes. Those who smoke, take the Pill or HRT, who are pregnant, who have spent a few days lying in bed or who have a family history of blood clots. You may be prone to clots without realising it.
So, what should I do?
John Belstead, Dr Kesteven and Professor Scurr all take an aspirin (which thins the blood); Professor Burnand's wife wears elasticated stockings (which compress the veins). You must drink lots of water and move your legs regularly. Don't take a sleeping pill and stay in one position.
If your meal has been left on your tray for more than 45 minutes, making it impossible to leave your seat, complain.
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Jackonicko...
Just wondering which 'Daily Telegraph' you found the article in? (There's one in Australia too!) I tried the online edition of the Telegraph and they have two stories relating to DVT - the October 23rd and November 10th ones, but neither of these are the ones you posted.
Do you recall the date your article was published?
Thanks!
Just wondering which 'Daily Telegraph' you found the article in? (There's one in Australia too!) I tried the online edition of the Telegraph and they have two stories relating to DVT - the October 23rd and November 10th ones, but neither of these are the ones you posted.
Do you recall the date your article was published?
Thanks!