The cost of fast-rotating backward-shift work among nurses

Introduction: 24-hour rotating shifts are common among hospital nursing staff to ensure continuity of care. There is mounting evidence that night shift work significantly impacts health and performance due to the alteration of natural homeostatic and circadian sleep processes. Nurses’ adaptability to night shifts is often affected by the speed and direction of the shift rotation (i.e., clockwise [forward] or counterclockwise [backward]). In forward-rotating shifts (FRSs), morning shifts are followed by afternoon and then night shifts. In contrast, backward-rotating shifts (BRSs) consist of night shifts followed byafternoon and then morning shifts. It is commonly assumed that forward rotation is easier to adapt physiologically because the human circadian rhythm moves forward. The association of BRSs with subjective and objective measures of sleep quality, daytime vigilance, sleepiness, and tiredness of health care workers has not yet been established. The present study aimed to investigate the association of shift rotation direction with tiredness, sleepiness, and sustained attention among two large samples of nurses working 8-hour FRSs or BRSs. Materials and Methods: Data of this cohort study were collected from nurses working at five Italian hospitals. The nurses had either a forwardrotating schedule (i.e., morning to afternoon to night) and or a backwardrotating schedule (i.e., afternoon to morning to night). Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Tiredness and Sleepiness data were collected using the Tiredness Symptom Scale and the Karolinska Sleepiness Scale. Sustained attention was measured using the Psychomotor Vigilance Task (PVT). Results: A total of 144 nurses (mean [SE] age, 41.3 [0.8] years; 92 women) participatedinthe study; 80nursesworking FRSs and 64nursesworkingBRSs. Both groups showed similar poor sleep quality rates (57.5% in FRSs group; 57.8% in BRSs group). Otherwise, there were significant differences between the BRS and FRS groups for sleepiness and all PVT variables. Specifically, nurses working BRSs demonstrated greater subjective sleepiness (F1,139¼41.23, P<.001) and significantly worse attentional performance on PVT (e.g., longer median reaction times: F1,139¼42.12, P<.001) than those working FRSs. Moreover, subjective tiredness and sleepiness were higher during the night shifts than the morning and afternoon shift (tiredness: F2,278¼67.91, P<.001; sleepiness: F2,278¼43.29, P<.001). Night shiftswere also associatedwithworse performance on the PVT (i.e., median reaction times: F2,278¼7.78, P<.001; fastest 10%: F2,278¼10.18, P<.001; minor lapses: F2,278¼4.37, P¼.01; reaction time distribution: F2,278¼8.88, P<.001). Importantly, these differences were not affected by age, years of employment, and quality of sleep. Conclusions: In conclusion, this cohort study confirmed the well-established negative effects of night shits and found that fast FRSs for nurses were associated with lower levels of sleepiness and higher levels of sustained attention compared with BRSs. Optimization of shift rotations should be implemented to decrease the combination of the negative outcomes associated with shift work and reduce the related risk of medical errors in health care systems.