Sleep Deprivation and Fatigue in Medical Personnel

Human error represents a significant risk to hospitalized patients, ^{[3] [368] [369]} and it has been estimated to play a role in more than 70% of anesthesia mishaps. ^[163] This is similar

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Providing quality health care requires physicians to attend to life-critical details such as the monitoring of changing vital signs, administering the correct type and dose of medications, and, in general, making crucial decisions to achieve optimal patient care. Physicians, like other workers, are affected by all the physiologic, psychological, and behavioral demands that characterize work environments requiring continuous, around-the-clock operation. However, whereas much of the health care system (e.g., nursing) relies on multiple work shifts to cover the 24-hour day (which is also not a perfect system), physicians more typically work long duty periods and frequently experience sleep loss, circadian disruption, and fatigue. Even minimal levels of sleep loss (for example, obtaining as little as 2 hours less sleep than an individual requires) can lead to lapses in performance, increased physiologic sleepiness during the daytime (including microsleeps), and altered moods. This level of degraded performance and alertness almost certainly contributes to medical error and health care mishaps.^[348]

Resident physicians, in particular, work long, grueling hours, often for years at a time. On-call duty periods commonly last 24 to 36 hours, occasionally even longer, and some resident groups work 100 to 120 hours per week though work hours in the United States are changing due to common work hours regulations being promulgated by the Accreditation Council for Graduate Medical Education. These schedule demands cannot help but lead to acute and chronic sleep loss, circadian disruption, and fatigue with subsequent adverse effects on performance, alertness, and mood. Therefore, individuals who administer life-sustaining care are at risk for making fatigue-related mistakes and causing costly medical errors.

Sleep and Performance

Previous studies addressed the effects of sleep deprivation and fatigue on physician performance and well-being. Major reviews of this literature identified little consensus.^{[83] [207] [223] [269] [348] [349] [370] [371] [372] [373]} There are several methodologic flaws in the existing literature:

1. The degree of acute sleep deprivation of subjects was poorly defined, and no assessment of chronic fatigue was made. Typically, studies relied on only the previous night's sleep as a level of "fatigue," and subjects could well have been chronically fatigued during baseline (control) trials, which could mask the degree of impairment resulting from the acute fatigue of being on call.
2. Measuring actual clinical performance is difficult and was not attempted. Most studies had to rely on simple cognitive tasks that probed only short-term memory, immediate recall, and simple reaction time; the validity of using such simple tests to probe complex performance has been challenged because these simple tests do not assess the higher-level cognitive functions most critical to skilled medical care. ^[244]
3. Most of the performance tests were of very short duration (3 to 5 minutes). Studies have shown that, if sufficiently motivated, even fatigued subjects can perform well on short-duration tasks.
4. Practice effects were not adequately accounted for. If subjects have not learned a particular performance test sufficiently to achieve maximum performance, subsequent trials will almost certainly show performance improvement because of further learning of the task.

Some studies requiring subjects to perform sustained vigilance tasks of long duration have, in fact, shown a performance impairment in fatigued physicians.^[223] Tasks of this type that require sustained attention to detail are highly relevant to the anesthetist's tasks, and they are the most sensitive to the effects of sleep loss and fatigue.

Do Anesthesiologists Perceive Fatigue as a Problem?

The survey by Gaba and associates^[292] revealed that more than 50% of respondents believed that they had made an error in clinical management that they thought was related to fatigue. In another survey of anesthesiologists and CRNAs, the majority (61%) of respondents recalled having made an error in the administration of anesthesia that they attributed to fatigue. ^[374] Data from these surveys reveal that issues of sleepiness and fatigue are perceived by anesthesia practitioners as being important causative factors in reducing anesthesia-related patient safety.

Howard and colleagues^[196] conducted a study of rested versus sleep-deprived anesthesiology residents using a realistic patient simulator. Multiple measures of performance were collected during this 4-hour experiment (e.g., psychomotor tests, reaction to secondary task probes, response to clinical events). In the rested condition, subjects had 4 consecutive days of sleep extension (showing up at work at 10:00 AM), whereas in the sleep-deprived condition they had remained awake for 25 hours (during a "pseudo" on-call period) prior to performing the simulated anesthetic. Subjects in the rested condition were able to increase their total sleep time over 2 hours from baseline. Psychomotor tests revealed a progressive impairment of alertness, mood, and performance over the course of the pseudo on-call period as well as on the experimental day, compared to the well-rested condition. Secondary task probe response times were slower after being sleep-deprived, although this reached statistical significance in one of three probe types. There was no statistical difference in the case management between conditions—in fact, subjects in both conditions made significant errors. The behavioral alertness scores in the sleep-deprived condition were different when compared to subjects who had increased their sleep time. Even when well rested, the subjects in this experiment did not perform perfectly; however, they did not show any of the behaviors indicative of being sleepy (e.g., head nodding, eyes closing). Sleep deprived subjects cycled (often rapidly) in and out of sleepy behaviors, and the most

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