Effects of shift rotation

Residency Program Insider, July 14, 2005

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 Dear residency program colleague:

Tackling resident fatigue requires an understanding of how shift work affects performance. Because residents work shifts, they experience circadian rhythm disturbances, have poorer sleep quality (i.e., more awakenings and less restorative sleep) compared to those who do not work shifts, and are more likely to complain of sleepiness after awakening and during work hours. Additionally, research shows that sleep after working night shifts is generally shorter than sleep after day work. The Agency for Healthcare Research and Quality reports that all of these factors contribute to sleep deprivation as indicated by less alertness during night work and a reduction in reasoning ability, which can lead to medical errors.

Scientific research has shown that the most important factors in evaluating a shift system include:

  1. Number of consecutive working days: Working too many consecutive working days may create two potential obstacles. First, the resident may suffer from an accumulation of fatigue. Second, the resident may suffer from isolation from family and social activities. Every resident needs a recovery period from work at regular intervals. However, because of variation in work environments, it is difficult to recommend a common limit. However, it is most beneficial to limit consecutive working days to five to seven days when working 8-hour shifts, and three to four when working 12-hour shifts.
  2. Duration of shift: Shift systems traditionally use 8-hour shifts. However, an increasing number of facilities have implemented 12-hour shifts. Even longer shifts (more than 16 hours) are often used in healthcare settings. When using extended shifts, ensure the following:

      • The workload is suitable for extended working hours
      • The shift system is designed to minimize the accumulation of fatigue (breaks during and between shifts)
      • There are adequate arrangements for covering absences
    • Time off between shifts: The amount and distribution of time off between both consecutive work days and blocks of work days are important factors to keep in mind. As consecutive hours within a given shift and/or the number of consecutive workdays in a work block mount, so do cumulative fatigue and stress. The rest period between shifts should provide enough time for the resident to get adequate sleep. A series of studies have shown that rest periods of 10 hours or less between consecutive shifts result in short sleep episodes-frequently only three to five hours of sleep. Thus, the time off between the end of one shift and the beginning of the next one should be at least 11 hours.

      That's all for this week!

      All the best,

      Acacia Aguirre, MD, PhD
      Medical Director
      Circadian Technologies, Inc.
      Lexington, MA

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