Mandating CMV OSA Screening
Alcohol or drug-impaired driving kills one person every thirty minutes in the United States. Distracted drivers kill nine people in the United States daily. Drowsy driving caused by sleep disorders results in 1,550 deaths, 71,000 injuries, and $12.5 billion damages annually (National Highway Traffic Safety Administration, 2014). Though laws exist to prevent inebriated or texting while driving, no national laws exist to prevent drowsy driving. The most common sleep disorder, obstructive sleep apnea (OSA), affects 25 million Americans and a disproportionate percentage of commercial motor vehicle (CMV) operators. Federal rulemaking of CMV operator alcohol and drug testing has existed since the United States Congress passed the Omnibus Transportation Employee Testing Act of 1991 (2012). However, no national laws presently exist to prevent CMV operator drowsy driving (Michaelson, E. (2014). Research suggests that the most effective ways to reduce automobile fatalities caused by sleep deprivation are to mandate screening of all CMV operators for obstructive sleep apnea, enact verifiable sleep testing protocols for these screenings, and enforce nationwide compliance for all commercial drivers’ license medical examiners.
It is important to first understand the pathophysiology and associated comorbidities of OSA. Obstructive sleep apnea (also known as sleep apnea hypopnea syndrome, sleep-disordered breathing, and colloquially, sleep apnea) is a sleep-related breathing disorder resulting from physical obstruction of the upper airway usually from the chin or tongue or due to absent tonus in the dilator muscles of the upper airway. Though affecting up to 5% of women and 7% of men across all demographics, OSA prevalence increases to as high as 41% in patients who are overweight (as defined by a Body Mass Index or BMI of 28 or higher) and as high as 78% in the obese. Amongst obese middle-age patients, 82% of men and 93% of women have undiagnosed OSA (Park, et al., 2010). Each airway collapse results in a temporary increase in blood pressure and stress hormone release, decrease in blood oxygen saturation and commiserate increase in blood carbon dioxide saturation. These physiological stressors substantially increase a patient’s risk for a heart attack, stroke, cancer, and overall morbidity. The associated sleep-related fragmentation from untreated OSA also increases daytime somnolence, reaction times, perception, and cognitive impairment.
Sleep deprivation is a national epidemic and primary factor in vehicle-related fatalities in the United States. According to the Centers for Disease Control and Prevention, one in five Americans suffers from chronic sleep-related disorders (Royal, 2002), with 1 in 25 adult drivers falling asleep while driving at least once in the prior thirty days (Centers for Disease Control and Prevention, 2009) and one out of every six fatal automobile accidents attributed to drowsy driving (Tefft, 2010). Consequently, the cost of preventable sleep deprivation automobile accidents is estimated up to $37.9 billion in annual damages (Leger, 1994, 84-93). In commercial driver fatalities, 14 million CMV licensees experience 341,000 annual crashes, resulting in approximately 4,000 annual deaths. One-third of commercial crashes result from commercial driver fatigue, the single largest factor in commercial accidents (Gurubhagavatul 2012). Additionally, OSA is the most prevalent sleep disorder increasing a driver’s risk for an automobile-related fatality or accident due to drowsy driving (Bhattacharyya, 2015). Unfortunately, despite its widespread prevalence, OSA is undiagnosed and untreated in up to nine out of ten sufferers, with law enforcement and healthcare providers rarely recognizing risk factors for drowsy-driving related automobile crashes (Blatt, et al., 1998).
To combat sleep deprivation fatalities, CMV operators should be required to be screened and treated for OSA. According to the Federal Motor Carrier Safety Administration (FMCSA) and the American Transportation Research Institute of the American Trucking Association, a joint-sponsored University of Pennsylvania study found that nearly one-third of CMV operators had OSA and up to 80% were likely suspect for OSA, triple the prevalence for the overall adult population when adjusted for morbid obesity, obesity, and normal weight variables (Pack, et al., 2002). However, despite this alarmingly high finding, the FMCSA’s latest 2008 guidelines still do not mandate OSA testing for CMV operators even when risk factors are present. Unfortunately, FMCSA’s Expert Panel Recommendations for CMV operators and OSA only recommend broad guidelines to consider testing as part of a CMV medical examiner’s physical exam and certification for operator fitness to drive when renewing one’s commercial driver’s license. In fact, though the Expert Panel recognized that a diagnosis of OSA “precludes an individual from obtaining unconditional certification to drive a CMV for the purposes of interstate commerce,” the guidance offered was recommended but not mandated (Ancoli-Israel, et al., 2008). As a result, CMV operators can drive commercial trucks on public roads—often at night—even if they have drowsiness-inducing and negligence-contributory OSA.
Mandatory screening of CMV for OSA will only be effective with verifiable sleep testing protocols for these OSA screenings. According to the American Academy of Sleep Medicine (AASM), diagnosis of OSA is standardized by calculating the number of apneic episodes (or breathing pauses) with 30% or greater airflow cessation ten or more seconds in duration averaged over the testing period, with a standard of five or more episodes per testing hour considered positive for OSA (Aurora, 2015). This OSA diagnosis calculation is known as the Apnea Hypopnea Index (named for the number of apneic and hypopnea respiratory episodes divided by the total time period of testing). Not all respiratory episodes identified by the American Academy of Sleep Medicine for calculation in a patient’s AHI as part of an OSA diagnosis can even be accurately measured or quantified by an HST (American Academy of Sleep Medicine, 2012).
Additionally, the AASM’s recommended testing period for diagnosis calculation purposes is for neurological sleep, excluding all periods of time where the subject is neurologically awake. This is the differential between what is known in medicine as Total Sleep Time (TST) during a neurologically-verified polysomnographic sleep study (PSG) performed in controlled medical center with licensed oversight and Total Recording Time (TRT), a non-verified total duration from a take-home sleep test (HST) where the operator takes the HST device home and self-tests alone without licensed oversight. As the table below demonstrates, the false negative differential with TRT HST instead of TST PSG is statistically significant when the total recording duration is utilized in place of the total neurologically-verified sleep time.
Nonetheless, FMCSA guidelines do not differentiate between TRT HST and TST PSG, permitting the individual CMV medical examiner the discretion of which testing modality to accept—examiners who, by FMCSA regulation, are not required to have any sleep medicine credentialing, boarding, or training when making said determination. This means that a CMV operator could test negative for OSA using an HST and be subsequently certified for safe driving even though a PSG would have tested positive for OSA with the accurate exclusion of non-sleep testing periods as recommended by the American Academy of Sleep Medicine. Unfortunately, HST’s can be either understated as a result of inaccurate duration sampling as explained in TST vs. TRT calculation for diagnosis (Michaelson, 2013), or the HST can be outright forged by having a third party take the HST for the CMV operator who has already tested negative for OSA (as is frequently discussed online in commercial driver message boards) (Vakulin, et. al., 2015). Therefore, without OSA testing protocols utilizing verifiable TST PSG instead of TRT HST, CMV operators can still test as ‘false-negatives’ or fraudulently pass testing altogether, thus negating the effectiveness of any mandatory testing without verifiable testing protocols.
With both mandatory and verifiable PSG testing, nationwide compliance by federal rulemaking for all CMV operators is both appropriate and not without precedent. Commercial driving is a function of interstate commerce, which means that a patchwork of inadequate, conflicting guidelines is problematic. An operator who lives in and begins a long haul in New Jersey, for example, may cross through one dozen states and countless cities and counties before completing his or her haul in California. Therefore, nationally standardizing CMV operator rulemaking is both appropriate and necessary. The European Union has already recognized the need for regulating OSA drivers throughout municipalities and across borders. Research within the Transport and Mobility Directorate of the European Commission resulted in revision to the EU Driving Licence Directive Annex III, mandating the testing and treatment of OSA drivers in EU member states effective December 2015 (Nicholas, et al., 2015). A similar approach to federal rulemaking in the United States would provide uniformity and consistency to an occupation that, in both practice and definition, crosses state lines.
OSA is a serious threat to the safety of drivers on American roads and particularly higher risk for CMV operators as a demographic. Unlike the general population operating single vehicles, CMV operators are responsible for significantly larger vehicles with heavier payloads, often driving much longer distances late at night. Whereas impaired or distracted driving is outlawed and CMV driver skill is verified, no verifiable, mandatory federal rulemaking presently exists for drowsy driving or OSA-related impairment in CMV operators. U.S.-based Research substantiates the approach EU rule makers are already implementing: the most effective way to reduce automobile fatalities caused by sleep deprivation is to implement national, verifiable sleep testing of all CMV operators for OSA.
This article is an opinion essay by a SleepSomatics clinician. The views expressed do not necessarily represent the views of SleepSomatics.
Annotated Bibliography
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