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Sleep Deprivation Same as Flying drunk

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Old 3rd Jan 2005, 13:30
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Sleep Deprivation Same as Flying drunk

Sleep deprivation shown to have as much impact on reaction time as alcohol



STANFORD - You'd get very concerned if, while waiting to board an airplane, you saw the pilot stumble out of the airport bar. New Stanford research suggests that you should be just as worried if you see the pilot yawning and rubbing his eyes.

In a test of reaction times, people who were tired because of disrupted sleep performed about as poorly as subjects who were legally drunk, the researchers report. The study is the first to show severe impairment in people who have only mild to moderate sleep disturbances.

Nelson B. Powell, DDS, MD, leader of the research team, said he hopes that the results will stimulate a discussion about the need for safety guidelines to cover sleepiness - rules that might resemble those already in place for blood alcohol levels.

Alcohol's slowing effect on reaction times is well documented, said Powell, who is co-director of the Stanford Sleep Disorders Clinic and Research Center. That is one reason why society demands that people responsible for the safety of others - truck drivers, train engineers, airline pilots - limit their alcohol consumption before working.

Yet, Powell noted, society does not seem to be as concerned about the harmful impact of sleeplessness, even though fatigue contributed to almost every high-profile accident in recent memory, from the grounding of the Exxon Valdez to the Chernobyl and Three Mile Island nuclear accidents.

Powell wants to see that change, so he and five colleagues set out to measure how the disorder known as sleep apnea affects reaction times. People with sleep apnea - about 24 percent of middle-aged men and 9 percent of middle-aged women - stop breathing multiple times during the night. These interruptions come during sleep, so the patient may not be aware of them, but they prevent the body from settling into a deep, relaxing sleep and result in daytime drowsiness.

Those with extreme apnea, who are often so tired that they may struggle to remain awake during a conversation or while driving to the corner store, clearly represent a danger. However, Powell's group wanted to learn if less severe forms of the disorder might also compromise safety.

So they recruited 113 patients with mild to moderate sleep apnea and compared their reaction times with those of 80 normal volunteers who had slept well the three previous nights. Members of the latter group took the reaction-time test sober to provide baseline data. Then they gradually got drunk on orange juice and vodka and performed the test three additional times: once at a blood alcohol level of 0.057 percent, again at 0.08 percent, and finally at 0.083 percent.

A blood alcohol level of 0.057 percent exceeds the legal limit for driving a commercial vehicle, which is 0.04 percent, but falls short of the limit to drive a car in California and many states, which is 0.08 percent.

Comparing the two groups on seven measures of reaction time - including average time, maximum time, and average of the ten fastest times - showed a surprising degree of impairment in the apnea patients. On all seven measures, their results were worse than those of the drinking group at a blood alcohol level of 0.057 percent. And on three measures, the apnea patients scored as badly or worse than the drinkers who were legally drunk. "That really stunned us," Powell said.

Taking one example, the average reaction time for the drinkers with a blood alcohol level of 0.057 percent was 263 milliseconds (just over a quarter of a second), which increased to 276 milliseconds by the time their alcohol level rose to 0.08 percent. The average time for the apnea patients was 266 milliseconds.

To put these numbers in perspective, Navy Top Gun fighter pilots typically score between 200 and 225 milliseconds, while a reaction time of 150 milliseconds lies beyond the capability of even the Michael Johnsons and Carl Lewises of the world. For that reason, response times of less than 150 milliseconds were not counted, Powell explained.

One of Powell's co-authors, David F. Dinges, PhD, a psychiatry professor at the University of Pennsylvania, developed the computerized reaction-time test for NASA as a way to evaluate pilots and astronauts. The 10-minute test is straightforward: the subjects push a button whenever a red light flashes. The length of time between flash and push is the reaction time.

Dinges created the test to be "learning-proof," Powell said. That is, because the flashes come at random intervals, you can't anticipate them or improve your performance through practice, as you could with, say, a video game.

Powell cautioned that he isn't proposing specific safety guidelines. But he hopes this study will start a national discussion and debate about whether such rules are necessary. For example, he suggested that it might be prudent to require airline pilots to pass a reaction-time test before they are allowed to fly. Alternatively, we might want to consider monitoring their sleep to ensure they are well rested when they sit down in the cockpit.

"Being arrested for sleepiness - that isn't going to happen, but maybe it should," Powell said. "It might make people in sensitive positions take responsibility."

Further research could focus on other ways in which mental or physical abilities suffer in the sleep deprived, Powell suggested. "I am showing you just one measure of abnormality in performance," he said.

The impact of the results extends to American society in general, Powell said. We are a weary nation, trying to work, study and lead our lives without sufficient sleep. Working at a university on the edge of frantic Silicon Valley, Powell sees plenty of patients who think they are exempt from the need for sleep. "Think of how much is lost in productivity because people don't respect sleep," he said.

The group's results appear in the October issue of the journal Laryngoscope.

Powell's Stanford colleagues on the paper are both from the Stanford Sleep Disorders Clinic and Research Center: Robert W. Riley, DDS, MD, associate clinical professor of psychiatry and behavioral sciences, and Christian Guilleminault, MD, professor of psychiatry and behavior sciences. The remaining authors are Marc B. Blumen, MD, an assistant professor of otolaryngology at Hopital Foch in Suresnes, France; and Kenneth B. Schechtman, PhD, an associate professor of biostatistics at Washington University School of Medicine in St. Louis, Mo.


### Sleep deprivation shown to have as much impact on reaction time as alcohol
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Old 3rd Jan 2005, 13:37
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Hope this will have an impact on subpart Q...
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Old 3rd Jan 2005, 14:46
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It is well documented that the most critical time of the flight is approach. I wonder how these result would differ if tetsed on someone who,

1. has some sleep deprevation before moving onto No.2. (Find me a truely quiet undistrurbed crew hotel. Home is impossible.)

2. has been locked in an immobile position for 10 hours, often in darkness.

3. been subjected to low hunidity and reduced Oxygen.

4. has spent a couple of hours with little mental activity in a darkened enviroment.

Conducting the tests after such a 'stage setting' would, I'm sure produce even more eye-opening results. Until we get the bean counters out of the decision making process I fear working conditions will not improve; (and this does not even take into account the 'always brushed under the carpet' issue of radiation exposure.) Once again medical research confirms what we've known or suspected for years, and yet it seems to be constantly ignored because it would be too inconvenient to take account of it. How many other transport industries went through trauma before action was forced upon the regulators? Most! Ours is surely next, but we are supposed to be proactive in this area of safety. It is what the passengers expect. In reality I have my doubts. Perhaps a report like this should find its way onto 'top table'. However, I'm sure the response will be, as it has been from so many chief pilots, that sleep management is an individual's responsibility and if it can't be managed correctly within FTL's, then you are in the wrong job. Crassness!
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Old 4th Jan 2005, 02:19
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Be careful what you wish for!

Gravity might get you on this one, creating another group of bean counters to worry about.

Take some supportive comments from the airline comunity, plus the boundless ambition of university people to find new topics to study, plus some political lobbying by a well-connected medical equipment manufacturer and then presto, you have a new regulation in the US or GB or EU that "all pilots must be tested for suitable reaction-time performance prior to operating the controls of an aircraft."

Think how interesting that could be in terms of labor relations, retirement considerations, and other non sleep- related aspects of the aviation workplace!


[from one who has spent many moonless nights, dog-tired, flying over mountains and deserts.]
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Old 4th Jan 2005, 10:02
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Being arrested for sleepiness - that isn't going to happen, but maybe it should," Powell said. "It might make people in sensitive positions take responsibility
So this guy thinks you should get arrested if you have a $hit nights sleep because you have noisy neighbours or a 1 month old kid... Nice.
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Old 4th Jan 2005, 10:46
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It might make people in sensitive positions take responsibility.
I would assume that is directed at those responsible for rostering and ultimately directors of the company, not the pilot unless sex chat lines throughout the night were their thing.
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Old 4th Jan 2005, 11:08
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here in oz, CASA produced an article a couple of years ago showing that being awake for more than 19 hours caused a reduction in reaction time aking to one at 0.05 BAC.

Then they introduced a fatigue management system allowing 19+ hour tours of duty (let alone awake times).

Yes, Minister.
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Old 4th Jan 2005, 18:02
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I can just see it now. The chief pilot calls you on the phone "if you don't get some sleep, you are gonna be in trouble Mr."

That would certainly put me to sleep. No pressure.

It will be FAA approved either way.

Safety is our number 1 concern at XYZ Airlines ... Unless it costs too much.
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Old 4th Jan 2005, 20:24
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No news there really, it's only what most of us know anyway but it doesn't make such a headline as a drink related story.
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Old 4th Jan 2005, 21:54
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It just shows the total hypocracy of those in positions of power. The fact that lack of sleep is exactly the same as being under the influence of alcohol has been well documented for several years. Do we see a drive to ensure well rested pilots? I haven't noticed it, but have noticed an almost hysterical drive to reduce the allowable blood alcohol to zero - and it should be remembered that alcohol is a natural metabolic byproduct.

I suppose that well rested pilots cost our dear employers money, but stopping them drinking doesn't.
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Old 4th Jan 2005, 23:23
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With tiredness, the right stimulation can often generate a bit of concentration for a limited time. I don't think you can do that with alcohol.
Its the accumulated fatigue that's the killer. Flying the aeroplane is nowhere near as dangerous as the drive home afterwards. FTLs forget that you can't store sleep in advance.
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Old 5th Jan 2005, 02:32
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WRT the dangerous drive home (fatigued) after a long duty, surely the company would have a duty of care that would see them liable if the unfortunate should hapened and you managed to 'fall asleep at the wheel' on the drive home.

I would be interested to hear how this ties in, liability wise.

PS 'Fatigue Management' read: I never managed to be so fatigued
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Old 5th Jan 2005, 06:18
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Jet_A_Knight

In respect of the UK they would have no liability, or duty of care. The employer is not forcing anyone to drive a car, its the choice of the person concerned.
The Highway code says don't drive if you are too tired.
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Old 5th Jan 2005, 07:14
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Jet_A_Knight

In the example you give (driving home after work) an employer is unlikely to be held liable, but it's not as straight-forward as bjcc suggests.
However, if an employer forced an employee to drive (or fly) during the course of his work when he was fatigued, then the employer might well be in breach of his duty of care and held liable for injury/damage caused.
It would depend upon the circumstances. eg Whether the employer was aware that the employee was fatigued, ignored the employee's protests that he was too tired, forced him to drive by threatening to fire him/disadvantage him at work etc.

bjcc
I think Jet was asking about possible civil liability, not road traffic offences/breach of the Highway Code etc
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Old 5th Jan 2005, 09:53
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Flying Lawyer,

Fatigue and campaigning for a sensible fatigue measure to be included in FTL’s is something I think is absolutely necessary.

I have noted both yours and bjcc’s posts and I am not heartened by what you have said. I am sure a good company ‘brief’ would pick all sorts of holes in the following, however, I do feel pressured to operate aircraft as well as drive to and from work when perhaps I am too tired to do so.

The regulations governing tiredness and fatigue, unlike alcohol, are self regulating. It is up to the individual to declare themselves fatigued and often the decision has to be made when the individual is too tired to make a level judgement. Always at the fore front of that decision is the knowledge of who will be shafted as a result of you calling in fatigued. Furthermore, the decision is based on very strong circular reasoning that does not favour a conscientious person.
1. The Company will establish a scheme for the regulation of aircrew flight times, duty times and the avoidance of fatigue.
2. Crew members have the responsibility to make optimum use of the opportunities and facilities for rest provided
3. Crew are responsible for planning and using rest periods properly in order to minimise incurring fatigue.
4. Crew members will not operate when fatigued.
In other words, you will not arrive at 4 if you have obeyed 1 to 3!
Lastly, we are members of a very small professional body. A trouble maker will not get a job with another company in such a close knit community. By rights, calling in fatigued is your responsibility, however…..

Do I fly and drive when I am tired? I don’t know because often I am too tired to tell.

Do I feel pressured?

Damn right I do!

Regards,
MrE.
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Old 5th Jan 2005, 10:28
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FL

Yes, I realise that he meant the civil side of it. I referred to the Highway Code as an indication that it is an individual responsibility to decide to drive home, or not when tired. That responsibility can't be 'over riddened' by an employer while driving 'off duty'

I am sure any company argument would be that they don't force you to drive to and from work, there are alternatives, ranging from public transport to moving house or job. If a person felt they were too tired then the decision to drive home is not a company matter.

As Police drivers we had the argument fairly often about fitness to drive at work. Under the shift system I used to work there were 2 'quick changeovers', (ie 8 hours between tour of duty) in every 4 weeks. During which you had to get home, sleep, eat, shower etc, then be back at work. However the pressure was always there to drive due to lack of other qualified drivers or everyone being in the same boat.

Last edited by bjcc; 5th Jan 2005 at 15:44.
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Old 5th Jan 2005, 15:26
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The Mystery
I understand what you mean by feeling pressured (and the problem of reporting fatigue), but it would be difficult to establish a breach of duty of care by an employer if the pressure was based simply on an employee's feeling.
The position would be different if an accident occurred during the course of work and it could be proved that the employer put pressure on an employee to continue working, ignoring complaints/protests of fatigue.

bjcc
You need to differentiate between:
(a) criminal offences (not under discussion here) and civil proceedings arising from an accident,
and
(b) whether the accident occurred on the way to/from work or during the course of work.

eg Fatigued employee falls asleep at the wheel and is prosecuted for a road traffic offence:
No defence that he was tired because his employer forced him to work long hours - regardless of whether the incident occurred on the way to/from work or during the course of work.

eg Fatigued employee, tired because his employer forced him to work long hours, falls asleep at the wheel, has an accident which gives rise to a civil claim:
On his way to/from work
- unlikely a claim against the employer would succeed, but there are circumstances in which it might.
During the course of work - if it could be proved the employer put pressure on him to continue working, then the employer may well be held liable - especially if the employer ignored complaints/protests of fatigue.
The extent of the employer's liability would depend upon the facts of the particular case. eg A court might decide the employee is X% liable for continuing when he knew he was fatigued and the employer Y% liable for putting pressue on him to do so.

You cite the Highway Code "as an indication that it is an individual responsibility to decide to drive, or not when tired." That is of limited relevance to a civil claim based on alleged breach of duty of care.
In a civil claim, it is only a factor which would be taken into account. It is not a complete answer, and would not absolve an employer from liability. The courts realise that employees can be put under enormous pressure to comply with employers' demands - no defence to a prosecution, but very relevant in a civil claim.

With respect, your approach is too simplistic and may mislead.
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Old 5th Jan 2005, 15:38
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Smile

FL

While I see what you are saying, the question was in the context of driving from work to home.

It was asked if the company would have a duty of care in that context. We have both given much the same answer to that. My reference to the HC was only made because that, in conjuction with a contract of employment would stop any thought of proccedings in that direction dead. I have edited what I said, and hopefully it reflects what I meant a bit better.

I fully accept what you say about driving at work. And am now signing up for English lessons.
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Old 5th Jan 2005, 15:43
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Out of interest: can anyone tells us of another profession, where the theoretical threshold of fatigue is estimated (FTL limits), and then an employer regularly rosters employees to work to that threshold or JUST below it?

Let's seperate answers into public safety related and those not.

Oh, and for good measure, does anyone know of professions where there is so much published medical data about the effects of said rosters. which is then ignored?
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Old 5th Jan 2005, 15:46
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RAT 5

I am not sure if anything is published, but try looking for Doctors hours. They did a fair amount of protesting about Junior Docs a few years ago and had the number of hours they were on duty reduced.

HGV Drivers hours are regulated, and it's enforced by use of a tachograph. Again though I don't know if there is a theoritical fatigue value attached to the reasons they were introduced or a number plucked from the air.
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