Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R21-OH-008392, 2011 Jan; :1-26
Introduction: Sustained work days (shifts lasting 12 hours or more) have become common in nursing, especially in combination with compressed schedules (e.g. three 12-hour days in succession). This work schedule limits the opportunity for sleep, and can lead to fatigue-related accidents, injuries, and long-term adverse health effects. Because neurocognitive performance changes are an early indicator of fatigue, they are useful for exploring the impact of sustained workdays on nurses. The proposed study examined sleep, sleepiness, fatigue, and neurocognitive performance over three successive sustained workdays among critical care nurses working in hospitals. The aims of the study were to: (1) describe the number of hours of sleep that nurses actually achieve over successive sustained workdays, (2) measure sleepiness, fatigue, and changes in neurocognitive performance over these workdays, and (3) describe the relationship between achieved sleep and fatigue, sleepiness and neurocognition. Methods: A within-subjects repeated measures design was used to compare changes from baseline in study variables over three successive days of 12-hour shifts. Female registered nurses from a large US hospital were recruited through flyers and by researcher attendance at nursing staff meetings. We screened 175 interested nurses by telephone for potential enrollment of whom 37 did not meet the inclusion criteria (i.e. nurses using sedating medications, pregnant, or with a serious emotional stressor in the past year). An additional 58 nurses were screened and eligible but did not enroll in the study because their work schedule did not conform to the study protocol near to the time of screening, resulting in the enrollment of 80 participants. When a nurse's schedule contained three consecutive 12-hour shifts preceded by two days off, she came into the research laboratory to complete baseline measures (demographic variables, OFER, HR-CESD), and to be trained on the protocol. Sleep patterns during the study period were assessed using actigraphy. Actigraphy recording began on the day off preceding the first of three 12-hour shifts, and ended after the first sleep period following the third 12-hour shift. A self-report sleep diary containing items based on the Pittsburgh Sleep Diary was kept concurrently during the entire actigraphy data collection period. Instruments measuring work demands were completed immediately after each shift. Both day and night shift nurses were included in the sample. We balanced the sample between day and night shift by increasing our face to face recruiting during the night shift hours. Results: Between 12-hour shifts, average TST was only 5.46 hours (SD=1.07) after the first shift, and 5.62 (0.91) hours after the second shift. For the sample, TST between shifts ranged from 2.7 to 7.8 hours, with 1/3 getting less than 5.2 hours of sleep, 1/3 getting between 5.2 and 6 hours, and the final third achieving 6.1 to 7.8 hours of sleep. Sleepiness scores were generally low, with only 17% of nurses scoring high at least once during the three shifts worked during the study (high- "fighting sleep"). Intershift fatigue was high in 22% of nurses using the OFER scale. This means that at the beginning of the next shift, nurses did not feel adequately recovered from the previous shift. Neurobehavioral functioning assessed by PVT followed the expected circadian pattern. Night nurses showed slower reaction times than day shift nurses, and there was decay in performance over the 12 hours of the shift, although not statistically significant. At the beginning of each 12-hour shift, nurses did not return to baseline on successive days, suggesting that there was not full recovery between shifts, and on average there was a significant slowing over the three study days. In this sample neurobehavioral status was not associated with prior sleep, level of sleepiness, or trait fatigue. Discussion: With TST of less than 6 hours for several nights per week, nurses may have difficulty remaining fully effective in their role. This should concern health care employers, as well as nurses themselves since both short term and long term health consequences are possible in addition to safety concerns.
Jeanne Geiger-Brown, PhD, RN, University of Maryland School of Nursing, 655 West Lombard St, Ste 575, Baltimore, MD 21201