Effects of Sleep Deprivation on Fire Fighters and EMS ... - NAEMT

More documents

Recommendations

Info

<strong>Effects</strong> <strong>of</strong> <strong>Sleep</strong> <strong>Deprivation</strong> on Fire Fighters and Other EMS Responders related, at least in part, to long work hours and sleepiness (Mitler, Carskadon & Czeisler, 1988; Wikipedia, 2007). However, disasters such as the Valdez are only the ’tip <strong>of</strong> the iceberg’ when it comes to adverse effects from long work hours and sleep deprivation. Acute sleep deprivation result from missing a single night’s sleep. However, more common are reductions in sleeping time over many days. This more insidious chronic sleep deprivation occurs when individuals repeatedly do not get ‘a good night’s sleep,’ which creates a sleep deficit or debt. Research indicates that decreasing sleep time by one hour a night for seven consecutive nights is equal to staying up for 24 hours straight once a week. Figure 1.3. Subject using apparatus to measure psychomotor vigilance. 1.4 Psychological <strong>Effects</strong> 1.4a Measuring Vigilance and <strong>Sleep</strong>iness To better study sleep deprivation, laboratory conditions and specific equipment have been designed to measure the effects <strong>of</strong> fatigue. One <strong>of</strong> most easily demonstrated effects <strong>of</strong> sleep deprivation is a decrement in alertness, as fatigued individuals experience brief periods <strong>of</strong> ‘micro-sleep.’ These momentary lapses are too brief to be noticed by the casual observer, but they create times when sleepy people are not attending to their environment, and they can be detected as a failure or a delay in responding to a stimulus. The ability to maintain alertness and quickly and accurately perform skills is measured with the psychomotor vigilance task (PVT) (Dinges & Powell, 1985; Doran, Van Dongen & Dinges, 2001), which is a portable, easily usable reaction-time test (Figure 1.3). The equipment requires individuals to respond to a small, bright red light by pressing a response button. This action stops the stimulus counter and displays the reaction time in milliseconds for one second. The subject is instructed to respond as quickly as possible, but not to press the button too soon (which will cause a false start warning). The interval between stimuli varies randomly from 2 to 10 seconds, and the total test time is 10 minutes or a total <strong>of</strong> 90 reaction times. The PVT is designed so that it has only minor learning effects, a necessary prerequisite for any test <strong>of</strong> psychomotor vigilance (Van Dongen & Dinges, 2000). Fatigue relates to a complex interaction <strong>of</strong> physiological, cognitive, and emotional factors. Fatigue results in slowed reactions, poor judgment, reduced cognitive processing <strong>of</strong> information, and an inability to continue performing a task or to carry it out at a high, sustained level <strong>of</strong> accuracy or safety. The pervasive problem <strong>of</strong> fatigue is due principally to one or more conditions including: lack <strong>of</strong> sleep; interrupted or poor quality <strong>of</strong> sleep (which denies opportunities for protracted deep sleeping periods); disrupted circadian work and rest cycles; and illnesses such as sleep apnea. 5
<strong>Effects</strong> <strong>of</strong> <strong>Sleep</strong> <strong>Deprivation</strong> on Fire Fighters and Other EMS Responders Table 1.1. The Epworth <strong>Sleep</strong>iness Scale How likely you are to fall asleep or ‘doze <strong>of</strong>f’ during these situations? would never slight chance moderate chance high chance doze <strong>of</strong>f <strong>of</strong> dozing <strong>of</strong>f <strong>of</strong> dozing <strong>of</strong>f <strong>of</strong> dozing <strong>of</strong>f 1. Sitting and reading 0 1 2 3 2. Watching TV 0 1 2 3 3. Sitting and talking 0 1 2 3 with someone 4. Passenger in a car for 0 1 2 3 an hour 5. Lying down to rest in 0 1 2 3 the afternoon 6. Sitting quietly after 0 1 2 3 lunch 7. In a car stopped for a 0 1 2 3 few minutes in traffic 8. Sitting inactive in a 0 1 2 3 public place, like a meeting or classroom Total number <strong>of</strong> points _____________ (The total [0 to 24] is the Epworth score, and a value <strong>of</strong> 10 or higher indicates excessive sleepiness. From Johns MW. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. <strong>Sleep</strong>. 1991;14(6):540–545.) The PVT has been used in the laboratory and in field studies to precisely measure, at brief intervals (typically every two hours <strong>of</strong> wakefulness), the changes caused by sleep loss under different conditions. Although only ten minutes <strong>of</strong> testing provides reliable results, PVT sensitivity to changes in alertness can be increased by lengthening the test (e.g., 20 minutes). This manipulation can be useful when studying the assessment <strong>of</strong> interventions purporting to reduce sleepiness (e.g., various pharmacologic agents, naps, work-rest schedules) or when evaluating more subtle degrees <strong>of</strong> sleepiness. In addition to measures <strong>of</strong> task performance, survey instruments are available to measure subjective ‘sleepiness.’ The most commonly used questionnaire is the Epworth <strong>Sleep</strong>iness Scale (Table 1.1) developed by Johns (1991). The Epworth <strong>Sleep</strong>iness Scale lists eight specific real-life situations, and the subject is asked to rate the likelihood <strong>of</strong> falling asleep during any <strong>of</strong> these activities. The total score can vary between 0 and 24, and values <strong>of</strong> 10 or greater indicate excessive daytime sleepiness. Subjective fatigue differs from alertness and has many mental and physical dimensions, only one <strong>of</strong> which is the impact <strong>of</strong> sleep and circadian rhythm disruption. Subjective fatigue also has both acute and chronic aspects. One <strong>of</strong> the difficulties in assessing studies <strong>of</strong> work hours and their consequences is the variability in instruments used to assess study subjects’ perceived fatigue levels (De Vries, Michielsen & Van Heck, 2003). Only recently have survey instruments been developed that are easy to administer and have robust psychometric properties <strong>of</strong> construct reliability and discriminant validity (Winwood et al., 2005 & 2006). 6
Page 1 and 2: Effects of
Page 13: Effects of
Page 64 and 65:
Effects of
Page 66 and 67:
Effects of
Page 68 and 69:
Effects of
Page 70 and 71:
Effects of
Page 72 and 73:
Effects of
Page 74 and 75:
Effects of
Page 76 and 77:
Effects of
Page 78 and 79:
Effects of
Page 80 and 81:
Effects of
Page 82 and 83:
Effects of
Page 84 and 85:
Effects of
Page 86 and 87:
Effects of
Page 88 and 89:
Effects of
Page 90 and 91:
Effects of
Page 92 and 93:
Effects of
Page 94 and 95:
Effects of
Page 96 and 97:
Effects of
Page 98 and 99:
Effects of
Page 100 and 101:
Effects of
Page 102 and 103:
Effects of
Page 104:
Effects of
show all

Effects of Sleep Deprivation on Fire Fighters and EMS ... - NAEMT

Create successful ePaper yourself

Delete template?

Save as template?