aviation raising sleep concerns

Sleep apnea

By David A. Lombardo
September 1, 2008
Safety
http://www.ainonline.com/news/single-news-page/article/sleep-apnea/

Statistics for the population at large suggest that there are pilots and mechanics out there trying to function in a mind-numbing state of perpetual exhaustion. All they really need to banish this perplexing and hazardous condition is a good night’s sleep each time they hit the hay.

Losing sleep is more than simply an inconvenience. Good slumber is essential for good health and clear mental and emotional functioning, and for this reason sleep disorders should concern pilots and maintenance technicians. The issue of sleep extends beyond duty and rest time for pilots, a different topic that is moving at snail pace through the regulatory review process, because even extended periods of rest time are ineffective if a pilot is not sleeping deeply enough to derive the proper restorative properties of a phase that accounts for about a third of our lives.

According to the National Sleep Foundation (NSF), approximately 70 million people in the U.S. have some sort of sleep problem. About 40 million Americans suffer from chronic sleep disorders and an additional 20 to 30 million are affected by intermittent sleep-related problems.

The NSF estimates sleep deprivation and sleep disorders cost Americans more than $100 billion annually in lost productivity, medical expenses, sick leave and property and environmental damage.

According to an NSF 2001 Sleep in America poll, nearly seven out of 10 Americans said they experience frequent sleep problems, although most have not been formally diagnosed by a medic. It found that two-thirds of older adults report frequent sleep problems; however, only one in eight say those problems have been diagnosed.
According to a follow-up poll the next year, 51 percent of Americans said they had driven while feeling drowsy in the past year; 17 percent said they had actually dozed off behind the wheel.

The National Highway Traffic Safety Administration conservatively estimates that 100,000 police-reported crashes, about 1.5 percent of all crashes, are caused by drowsy drivers each year. These accidents result in more than 1,500 fatalities and 71,000 injuries and an estimated $12.5 billion in diminished productivity and property loss.

Health and Safety Risks

One such sleep-related ailment is sleep apnea, a particularly insidious disorder since people who have it are often not aware that they have a disease and are reluctant to talk about the symptoms because of the impact on their professional life. People with untreated obstructive sleep apnea stop breathing repeatedly during their sleep, and eventually (sometimes after a minute or longer) the brain rouses the body from this asphyxiation, thus never allowing the sufferer to enter the deep, restorative REM (for rapid eye movement) phase of a good night’s sleep. This cycle can repeat itself hundreds of times a night, and the sufferer greets the new day mentally and physically exhausted, a condition that must be fought off until bedtime.

Studies have shown that about one in four men have sleep apnea but fewer than one in 20 of them know it. About 13 percent of women have the disorder, with only one in 50 recognizing it. That’s not surprising, because the worse the apnea becomes, the more impaired a person’s cognitive abilities become, and the less likely one is to recognize a problem.

One of the warning signs of sleep apnea is snoring. If you snore and have any of a number of additional symptoms (see sidebar on page 65) it is possible you have sleep apnea.

Many people accept snoring as a fact of life for men as they age. While it can be harmless for most people, for some it can be literally life threatening. A person who seeks a consultation about sleep apnea is first asked whether he snores and whether he stops breathing during the night.

Snoring means your airway is partially blocked. When breathing occurs through an obstructed airway, the air moves faster, causing a vibration in the structures nearby, resulting in snoring.

Attempting to breathe through a narrowed airway requires a great deal of effort. It is not only exhausting but may also further collapse the airway. Sometimes the airway collapses entirely, allowing no air in or out. The body has a protective system that partially wakes a person who is struggling–or unable–to breathe. The pause in breathing reduces blood oxygen levels, can strain the heart and cardiovascular system, and can increase the risk of cardiovascular disease.

Mark Rosekind, Ph.D., president and chief scientist of Cupertino, Calif.-based Alertness Solutions, says apnea is far more common than most people realize. “If you know someone with asthma then you know someone with apnea because statistically apnea is more prevalent in society.”

Rosekind said trucking is the only industry where there’s some data about prevalence amongst operators, thanks to a lab study at the University of Pennsylvania in 2006 that the trucking industry supported. The study found that about 28 percent of drivers had sleep apnea.

“We have no studies in aviation, but pilots should be on the lookout for it,” Rosekind cautioned. “As far as the FAA goes, if you have a condition and you can treat it, you can fly. Sleep apnea is treatable, so it shouldn’t ground anyone once you’re being treated for it.”

He pointed out that there are two kinds of associated risk: personal health and safety. “Personal health risks are well documented, though the jury is still out on the subject of organ failure. Loss of memory, decreased capacity to learn and decreased attention may never be fully recovered after treatment; there may be permanent damage,” he said.

The other risk factor is public safety. “People with apnea have a six times greater risk factor for car accidents, and some studies conclude that the risk could be as much as nine times greater. People with mild to moderate apnea can show performance degradation equivalent to .06 to .08 blood alcohol level, which is legally intoxicated in most states. The implication for pilots is significant.”

Rosekind said changing time zones and alcohol consumption exacerbate the problem because they inhibit a person’s ability to wake up. He said, “Normally, when a person stops breathing his brain wakes him up in about 10 seconds and he gasps for air.
Multiple time zone changes and alcohol consumption both inhibit your arousal mechanism and may result in oxygen deprivation for 30 seconds or longer before arousal occurs. When you add up the oxygen starvation resulting from many occurrences per night, the effect can be significant.”

According to Dr. Barbara Phillips, chair of the National Sleep Foundation, the consequences of sleep loss are substantial. “Historic tragedies have been linked to fatigue-related human error, among them the Exxon Valdez oil spill and the NASA Challenger shuttle explosion.

“Although we naturally think of sleep as a time of rest and recovery from the stresses of everyday life, research is revealing that sleep is a dynamic activity, during which many processes vital to health and well-being take place. New evidence shows that sleep is essential to helping maintain mood, memory and cognitive performance. It also plays a pivotal role in the normal function of the endocrine and immune systems. In fact, studies show a growing link between sleep duration and a variety of serious health problems, including diabetes, hypertension and depression,” she said.

Extensive literature on the subject of sleep apnea also stresses the relationship between the quantity and quality of one’s sleep and many health problems. For example, insufficient sleep affects growth hormone secretion that is linked to obesity; as the amount of hormone secretion decreases, the chance for weight gain increases.

Research has also shown that insufficient sleep impairs the body’s ability to use insulin, which can lead to the onset of diabetes. An increasing number of studies show a correlation between insufficient sleep and disease.

Dr. James Allen, an environmental health physician from Wilmington, Del., and author of Working Healthy, says there is clearly a relationship between obstructive sleep apnea and reduced vigilance.

“While apnea is certainly a problem for pilots, technicians don’t get a pass. Inspecting an aircraft requires vigilance and concentration. When looking for fatigue cracks, chafing on wires and telltale stains they will be obvious only to those who are watchful and alert. Sleep deprivation results in drowsiness, which reduces vigilance.”

Sleep Analysis

The symptoms of sleep apnea are all too familiar to Marlin Priest, director of maintenance for McWane of Birmingham, Ala. Priest supervises four full-time technicians, a hangar attendant and an intern. His flight department has two Learjet 45s and a GIII. Priest has been diagnosed with severe sleep apnea.

“Apnea had a daily effect on my work,” he said. “By about two o’clock in the afternoon I would hit a wall energy-wise. In a large group setting such as a conference I would lose concentration and even fall asleep. In the shop I would have to reread things over and over to remember them. I would talk to my mechanics then not remember what we talked about. Driving home late afternoon and early evening, I was having a difficult time concentrating, and I would wake up every morning with a headache. I thought it was a sinus problem.”

Priest said his wife, a nurse, forced him to recognize he had a problem. “My wife said, ‘If we’re going to sleep in the same bed, you’re going to have to get help,’” he said. “She recognized that I wasn’t just snoring at night; I would actually stop breathing. I did the sleep study and they found I was having an episode about every 58 seconds all night long.”

A sleep study requires an overnight stay at a sleep disorder clinic. The subject has numerous electrodes glued to his head, chest and legs with all the wires coming together into a single bundle and plugging in next to the bed. There is also a small breathing-detection device placed under the nose that is identical to a general aviation oxygen cannula used in non-pressurized aircraft. A computer silently monitors numerous physiological variables while the subject sleeps.

The results yield information about the rate of respiratory disturbance, oxygen levels, arousals from sleep due to snoring, cumulative amount of REM sleep, and number of limb movements resulting in arousal to a lighter stage of sleep. Based upon the results, various forms of treatment may be recommended. These vary from weight loss to using a continuous positive airway pressure (CPAP) device, which consists of a mask and air compressor system that blows air in your nose or nose and mouth to keep the airway open.

Priest said his results indicated his oxygen level dropped as low as 79 percent; it should not go below 90 percent. He was told to return for a follow-up study using a CPAP mask and as a result was fitted with one to use every night.

“Once I started using CPAP it took a while to get comfortable with it but when I did I went from getting almost no sleep to sleeping seven or eight hours a night with no fatigue, headaches or grogginess in the morning. Now my energy level lasts all day; I don’t get tired in the afternoon anymore. It has been a huge turnaround in my general health and energy levels,” he said.

For those who travel frequently, CPAP machines come small enough to be packed in a suitcase, along with their hose, mask and global voltage transformer.

Alternative Treatments

However, there is another possibility. Keith Thornton, DDS, of Airway Management in Dallas, invented the TAP (Thornton Adjustable Positioner) as an alternative to CPAP.

“Your windpipe is flexible so you can swallow and the airway opens and closes.
During the day your brain keeps your airway open, but when you go to sleep your muscles relax and in some people certain conditions can cause the airway to collapse,” Thornton said.

“One way to correct the problem is through surgery by removing tissue from the back of the throat, but it doesn’t have a very good success rate and it’s painful.”

Thornton said for years there were two choices: surgery or CPAP. “Unfortunately, the patient compliance rate with CPAP is extremely poor, according to about a dozen studies,” he said. “When used properly it works fine, but different studies have indicated compliance rates as low as 43 percent. It’s cumbersome, and as a result patients either stop using it or they wear it for only a few hours then take it off.”

Thornton emphasized that sleep apnea is a lifetime disorder and the treatment must be conducive to the individual’s lifestyle. “CPAP must be taken out at the airport [for security inspection of carry-on baggage] like a computer. How embarrassing is that? Women don’t like the straps in their hair and many people just can’t sleep on their back. Fortunately there’s now a third choice: TAP.”

TAP pulls the lower jaw forward essentially the same way a paramedic does before administering CPR. It works because the tongue and surrounding anatomy are connected to the jaw. Pulling the jaw forward causes the tongue to come forward with it and out of the way of the airway.

The TAP, also known as an “oral” or “dental appliance,” consists of two custom-made trays that fit over the teeth and connect in front with a clasp that can be adjustable to change the positional relationship between the upper and lower teeth. The farther forward the lower jaw moves, the more the airway opens. The idea is to set it far enough forward to reduce, if not entirely eliminate, the apnea.

Thornton said he sells TAP devices to all three military branches and the VA hospital system. “Air Force pilots diagnosed with sleep apnea are taken off the flight line unless they’re able to wear a TAP. Then they’re issued two TAPs and returned to flying status. They’re small, they don’t require electricity and there’s a higher incidence of compliance over CPAP,” he said.

He cautioned against buying pre-made dental appliances on the Internet. “It’s a problem for several reasons. First, you don’t get a baseline initial evaluation necessary to determine if the treatment is working. Second, most are not custom fitted and won’t do the job. Those that do offer custom fit send you the materials to do the impression but you have no training. Finally, there’s no follow-up study to see if it’s working.”

Richard Craig, DDS, of the Midwest Dental Sleep Center of Shorewood, Ill., underscored the problem with CPAP. “If you don’t use it, it doesn’t do you any good and many people simply don’t like using it. Using oral appliance therapy has a significantly higher percentage of adherence. It means no more hoses, straps or headgear, sleeping in any position you wish, low maintenance and easy to travel with.”

Craig explained that in some severe cases a patient might use both an oral appliance and CPAP. “The point of treatment is to restore you to a normal condition or get as close to it as possible. There are occasions when we’ll recommend using both, but the advantage of using the oral appliance with CPAP is you can cut the air pressure in half, making it a more comfortable experience.”

According to Craig, the other advantage of using an oral appliance is that you can do follow-up testing in your own home. “We now have devices you can take home that will give us the information we need to determine if the appliance is doing the job. I want to test you in your own home the way you normally live. If you have a glass of wine before bed I want that to be part of your test.”

“It is very simple to use. You put a strap on your forehead, a small tube comes around to your nose like a cannula and you can sleep in any position you wish. When you’re done you bring it to us, we plug it into the computer and it downloads the data,” he said.

Sleep apnea treatment is not inexpensive. You may need several sleep clinic studies to be sure the device works properly and compare your results to your baseline to see if you’re improving.

A CPAP machine and mask can run from a few hundred dollars to more than $1,000. An oral appliance program, including original consultation, a custom fitted device, adjustments and follow-up studies can be $2,500 to $3,000. It is also an ongoing process, with patients undergoing an annual evaluation to be sure the device is still effective.

If you are diagnosed with apnea you’re only halfway down the road to a cure and about to face potentially the most trying aspect of the disease–insurance coverage.
Craig said that while a growing number of insurance companies recognize sleep apnea testing and treatment, unfortunately many medical plans are still in the process of determining their amount of coverage. Still more call it experimental and refuse to cover it.