Axiom
2001; Lippincott Williams & Wilkins; Volume: 23; Issue: 2 Linguagem: Inglês
10.1097/00132981-200102000-00010
ISSN1552-3624
Autores Tópico(s)Sleep and related disorders
ResumoIn my lifetime, I have fallen asleep while driving on only one occasion. I had just finished working a 12-hour overnight shift in a Philadelphia emergency department. Shortly after beginning my journey home through rush hour traffic, my sleepiness became more pronounced, and I momentarily fell asleep while stopped at a red light. I do not recall falling asleep, but I remember vividly the intense fear I felt after waking up to see my car idling forward into the rear-end of another car. Luckily, for whatever reason, I woke up in time to apply my brakes quickly, thus avoiding what seemed to be an inevitable collision. I was certainly fortunate this time, but it did make me ponder about all those other times I had driven home after overnight shifts. This event introduced me to the realization that our profession's practice of driving home after certain shifts can be a dangerous and risky endeavor. Motor vehicle crashes are a leading cause of injury and death in the United States.1 In recent years, health and safety experts have raised concerns about the potentially devastating consequences of sleepiness in highway crashes.1 Sleepiness has been blamed for approximately 200,000 to 400,000 motor vehicle collisions per year in the U.S.2 The National Highway Traffic Safety Administration attributes about four percent of all fatal motor vehicle collisions annually to driver sleepiness.2 Total estimated cost of motor vehicle crashes related to sleepiness had been reported to be $43.15 billion in 1988.3 This problem is not unique to the United States. Based on police surveys in England, sleep-related vehicle collisions were estimated to comprise about 16 to 23 percent of road crashes. This survey study remarked that these types of crashes can occur after even a short period of driving.4 In addition, the morbidity and mortality associated with sleep-related collisions is higher, probably because of a greater speed of impact.4 Time of day (circadian) effects are profound, with sleep-related collisions being particularly evident during night shift work and driving home afterwards.4,5 EPs at Risk Emergency physicians and other shift workers are at high risk for sleep-related crashes. Workers who have not fully adapted to night shifts are especially at risk. Several studies have consistently shown the dangers of sleep deprivation on driving safety. One population group at risk is medical housestaff. A study of pediatric residents showed that 44 percent of housestaff reported having fallen asleep while stopped at a red light. All of these episodes occurred when the housestaff were driving home post-call. Other groups also have been studied. When compared with day only or evening only nurses, those nurses with rotating shift schedules had 3.6 times the odds of nodding off while driving from work.7 The occupational risk of motor vehicle collisions for emergency medicine residents has been only recently reported.2 A self-administered survey distributed to all emergency medicine residency programs revealed some alarming statistics. Approximately 74 percent of motor vehicle collisions were reported to occur following the night shift, compared with approximately 12 percent of the collisions following the day shift.2 The results of this study demonstrated the significant occupational risk for emergency medicine residents driving home after a night shift.2 Although the onset of sleep can go unrecognized, drivers are typically aware of sleepiness prior to a driving incident. The safe operation of a motor vehicle requires alertness as well as quick and accurate perception, judgment, and action.1 Sleepy drivers risk injury and death, not only from falling asleep while driving but also from loss of attention or slowed reactions during critical driving tasks or maneuvers.1,2,8 Studies concur that night duty contributes to significant slowing in cognitive processing along with a decline in reaction times in vigilance testing.9 Sleep is a complex process with multiple physiological and behavioral components. Sleeping less than the biological need results in a cumulative sleep loss or sleep debt. Without adequate sleep, this debt accumulates until the brain signals the body to obtain sleep. Sleepiness is a normal manifestation of the biological need for sleep. It is characterized by a tendency to fall asleep, and is the unavoidable consequence of the unsatisfied need to sleep.1 Fighting Off Sleep Drivers falling asleep are unlikely to recollect the onset of sleep, but will be aware of the precursory state of increasing sleepiness, typically reaching a state of fighting off sleep prior to a crash.5 Many methods have been employed by drivers for countering the effects of sleepiness.1,2,5,10,11 Adopted countermeasures to increase alertness such as opening a window to let in fresh air, listening to the radio, talking, or exercising are of only temporary or no benefit.1,2,5,10 Sleepiness is such a potent biological signal that no matter how well motivated an individual may be, the brain can and will initiate sleep.1 Effective countermeasures supported by studies entail a 30-minute break from driving, including a short nap (less than 15 minutes) and/or 150 mg of caffeine (the equivalent of about two standard cups of coffee).5,10 It is of substantial importance for emergency departments to appreciate this occupational hazard of driving after night shifts. With awareness and education, the incidence of sleep-related collisions might be reduced. Drivers are typically aware of sleepiness prior to a driving incident. Although the onset of sleep can go unrecognized, some investigators have stated that it is not possible to fall asleep at the wheel without feeling sleepy first.10 Emergency physicians must therefore be aware of the inherent risks of driving sleep deprived after a night shift. Sleep can occur without warning, and can affect all drivers. The only way to reverse the physiological need for sleep is to sleep. Therefore, the most effective countermeasure of all in the prevention of sleep-related motor vehicle collisions might be short and simple — take a 15-minute nap. The axiom: Finished a night shift? Always take a brief nap before you drive.
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