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

Introduction: 24-hour rotating shifts are common among hospital nursingstaff to ensure continuity of care. There is mounting evidence that nightshift work significantly impacts health and performance due to the alterationof natural homeostatic and circadian sleep processes.Nurses’ adaptability to night shifts is often affected by the speed and directionof the shift rotation (i.e., clockwise [forward] or counterclockwise[backward]). In forward-rotating shifts (FRSs), morning shifts are followedby 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 physiologicallybecause the human circadian rhythm moves forward. The associationof BRSs with subjective and objective measures of sleep quality,daytime vigilance, sleepiness, and tiredness of health care workers has notyet been established. The present study aimed to investigate theassociation of shift rotation direction with tiredness, sleepiness, and sustainedattention among two large samples of nurses working 8-hour FRSsor BRSs.Materials and Methods: Data of this cohort study were collected fromnurses working at five Italian hospitals. The nurses had either a forwardrotatingschedule (i.e., morning to afternoon to night) and or a backwardrotatingschedule (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 SymptomScale and the Karolinska Sleepiness Scale. Sustained attention wasmeasured 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 betweenthe BRS and FRS groups for sleepiness and all PVT variables. Specifically, nursesworking BRSs demonstrated greater subjective sleepiness (F1,139¼41.23,P<.001) and significantly worse attentional performance on PVT (e.g., longermedian reaction times: F1,139¼42.12, P<.001) than those working FRSs.Moreover, subjective tiredness and sleepiness were higher during the nightshifts than the morning and afternoon shift (tiredness: F2,278¼67.91, P<.001;sleepiness: F2,278¼43.29, P<.001). Night shiftswere also associatedwithworseperformance 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; reactiontime distribution: F2,278¼8.88, P<.001). Importantly, these differences werenot affected by age, years of employment, and quality of sleep.Conclusions: In conclusion, this cohort study confirmed the well-establishednegative effects of night shits and found that fast FRSs for nurseswere associated with lower levels of sleepiness and higher levels of sustainedattention compared with BRSs. Optimization of shift rotationsshould be implemented to decrease the combination of the negativeoutcomes associated with shift work and reduce the related risk of medicalerrors in health care systems.