What is sleep apnea? Hypopnea is the reduction of breathing for about 10 seconds. Sleep apnea is the cessation of breathing during sleep. It usually occurs in most people over age 50, and to be significant the person usually stops breathing for at least 10 seconds. It is important to point out that normal physiologic changes occur with sleep that are necessary for sleep, such as muscle relaxation, including muscles of the upper airway, that will make us all somewhat vulnerable to periods of hypopnea or apnea in our sleep. But to be significant, those apnea/hypopnea episodes should last 10 seconds or more. Those who are at risk for sleep apnea may be more prone to developing significant episodes of apnea that can have both short term and long term consequences.
Types of Sleep Apnea: It is usually categorized into three types -OSA or upper airway obstructive sleep apnea; CSA or central sleep apnea-when airflow stops at nose and mouth and breathing effort by diaphragm and other muscles of respiration stops; And mixed sleep apnea, which is a combination of both. CSA itself is not as common as OSA and is generally associated with neurological disorders such as stroke, ALS (amyotrophic lateral sclerosis), and Parkinson’s disease. Dr. Chokroverty in his book (listed in the references below) explains the physiology of sleep apnea. To summarize, in OSA , air doesn’t reach the lungs, blood oxygenation falls, and carbon dioxide level rises. The diaphragm (which act as bellows) will work with the muscles of the chest wall to overcome the obstruction, and the brain will signal the individual to wake up. Once awake the person regains muscle tone and the obstruction is eliminated. Normal breathing resumes until the person falls asleep and the whole cycle begins again. Thus the classic symptoms of loud snoring, pauses in breathing and the gasping for air that we see with sleep apnea. Now imagine that happening twenty to sixty times or more per hour at night. Restorative sleep is significantly interrupted. In the long run this can place tremendous strain on the cardiovascular system leading to many adverse medical conditions ranging from high blood pressure, coronary artery disease, irregular heartbeat, and stroke. Also, increased daytime sleepiness and cognitive impairment can lead to increased work and traffic related accidents.
Risk factors for sleep apnea: Being male, increasing age, obesity, and increased neck size of 17 inches or more in men, and 16 inches or more in women, smoking , and the use of any central nervous depressant such as alcohol or sedative hypnotic type of drugs often used as sleep aids. Alcohol and these type of drugs can further reduce muscle tone and increase the strength of stimuli needed to arouse the brain, hence the sleeping hypoxemic individual. Other risk factors include family history, ethnicity, and certain anatomical factors that cause recessed chin, small jaw, or large overbite.
Sign and symptoms of sleep apnea: Loud snoring, frequent urination at night. The affected individual may exhibit excessive daytime sleepiness, headaches, falling asleep at inappropriate times, lack of concentration and memory impairment. There has also been association with depression and sexual dysfunction such as decreased libido and erectile dysfunction.
FMCSA and sleep apnea: According to a National Sleep Foundation (NSF) study performed in 2005 more than 18 million Americans have sleep apnea. Another study conducted by the University of Pensylvania sponsored by the FMCSA and others in the industry showed that commercial truck drivers are at a higher risk than the average population, with a 28% rate of sleep apnea. Of those 17.6% have mild sleep apnea, 5.8% have moderate sleep apnea, and 4.7% have severe sleep apnea. Sleep apnea is reported in some studies to increase risk of accident by up to seven times. According to the FMCSA most states have adopted the guidelines of 391.41 (b)(5) of the Federal Motor Carrier Safety Regulation (FMCSR) and have determined that sleep apnea is disqualifying and have the jurisdiction to suspend that driver’s CDL.
The FMCSA further states: Approximately 70% of the cases of excessive daytime sleepiness (EDS) are caused by narcolepsy and obstructive sleep apnea (OSA). Treatments for OSA include surgery and continuous positive airway pressure (CPAP). The successfully treated driver may be considered for certification following the recommended waiting period. You should not certify the driver with suspected or untreated sleep apnea until etiology is confirmed and treatment has been shown to be stable, safe, and adequate/effective.
Severity of sleep apnea (apnea /hypopnea index): mild 5+ episodes/hr; moderate 15+ episodes/hr; severe 30+ episodes/hr. More than 30 episode/hr is considered a diagnosis of OSA.
See: FMCSA Sleep Disorder Tests
FMCSA Guidance/Advisory criteria for The Treatment Of Chronic Sleep Disorders
What to do: This is the real upshot here. I reviewed the last issue of The Commercial Driver Medical Examiner Review (A quarterly newsletter from ACOEM-The American College Of Occupational and Environmental Medicine ): What’s important to remember is that whatever confusion exists regarding the screening of commercial drivers with suspected sleep disorders, the treatment for sleep apnea and the recent Sleep Apnea bill signed into law by President Obama last October, no one (that includes most of all medical examiners, drivers and motor carriers alike) should interpret this as to mean that they need to do nothing. The duty of the medical examiner is to always utilize best medical practice when evaluating a driver to determine whether or not there exists any medical condition that may affect his or her ability to operate a commercial vehicle.
Conclusion: This is true in all cases, whether the condition is diabetes, hypertension, sleep apnea, medications etc.. Standards or Regulations are laws and must be followed. Although there are currently no Standards or Regulations passed regarding the screening and treatment of sleep apnea in the commercial driver, there are plenty of Guidelines available for examiners to follow as good practice. Guidelines are based on Medical Review Board Studies/Advisory panels and aid the examiner in making a certification decision. As was reviewed in the ACOEM’s recent newsletter, the bill that was passed mandates that any new or revised requirement for the screening, testing, and treatment of sleep apnea be adopted through the rule making process. However, it does not prohibit guidance nor does it require a regulation or standard to be passed.
What to do? There’s plenty of guidance available to help one make that decision. What not to do, is to do absolutely nothing.
References:
1. Questions & Answers About Sleep Apnea, 2009. Sudhansu Chokroverty, MD, FRCP, FACP
2. Commercial Driver Medical Examiner (CDME). American College Of Occupational And Environmental Medicine (Winter 2014). Natalie P. Hartenbum MD, MPH, FACOEM Editor in Chief
3. FMCSA Medical Examiner’s Handbook-Available online.
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