Tuesday, February 11, 2014
The Slippery Slope Of OSA
The FAA ignores obvious accident causes when it focuses on Obstructive Sleep Apnea
A mandatory OSA testing plan of medical certificate applicants was announced by FAA flight surgeon Dr. Fred Tilton. In its efforts to justify the testing, the FAA pointed to NTSB recommendations and the Safety Board's accident files. The plan's most vocal critics, AOPA and EAA, found that OSA has never been the probable cause of an aviation accident and has never been demonstrated to adversely affect aviation safety. I found the same thing.
A serious concern is that by requiring mandatory testing for a condition that has no history of accident causation, the FAA starts down a slippery slope that could lead to mandatory testing for numerous other conditions based on bureaucratic whim rather than demonstrable safety impact.
According to the Mayo Clinic, obstructive sleep apnea occurs when your throat muscles intermittently relax and tissue blocks your airway during sleep. It may cause you to wake up. Loud snoring punctuated by periods of silence is a typical characteristic. It's estimated that about 4% of males and 2% of females in the general population are affected, but a study cited by the FAA suggested a 7% overall figure. Alcohol use, smoking and diabetes are known to increase the risk of having OSA; it's not just tied to being overweight or having a large neck circumference.
A Mayo Clinic study found that if you have 20 or more apnea episodes per hour of sleep, causing your blood oxygen level to fall as low as 78%, you're at increased risk of sudden cardiac death during the sleep period, typically including the hours of midnight to 6 a.m. People without sleep apnea die more often from sudden cardiac death between 6 a.m. and noon.
I don't know any pilots who fly between midnight and 6 a.m. while asleep, but I know many who do fly between 6 a.m. and noon while awake. The FAA claims that if your sleep is interrupted because of apnea episodes during the night, you'll be tired during the day. Of course, there are many other things that can interrupt your sleep, from a crying baby, to noisy garbage trucks and low-flying aircraft, and worry about your upcoming FAA medical exam.
Although the FAA claims that OSA is "almost universal" in overweight people with a body mass index (BMI) greater than 40, that's not true according to a study by the University of Texas Health Science Center. In patients who were being evaluated for weight-loss surgery, the incidence didn't enter the range I'd call "almost universal" at 95% until the BMI was greater than 60, which is more than severely obese.
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