Twelve-hour night shifts of healthcare workers: A risk to the patients?

We assessed the impact of 12h fixed night shift (19:00-07:00h) work, followed by 36h of off-time, on the sleep-wake cycle, sleep duration, self-perceived sleep quality, and work-time alertness on a group composed of 5 registered and 15 practical nurses. Wrist actigraphy (Ambulatory Monitoring, Inc.), with data analysis by the Cole-Kripke algorithm, was applied to determine sleep/wake episodes and their duration. The sleep episodes were divided into six categories: sleep during the night shift ((x) over bar = 208.6; SD +/- 90.6mins), sleep after the night shift ((x) over bar = 138.7; SD +/- 79.6min), sleep during the first night after the night work ((x) over bar = 318.5; SD +/- 134.6min), sleep before the night work ((x) over bar = 104.3; SD +/- 44.1min), diurnal sleep during the rest day ((x) over bar = 70.5; SD +/- 43.0min), and nocturnal sleep during the rest day ((x) over bar = 310.4;.SD +/- 188.9mins). A significant difference (p < .0001; T-test for dependent samples) was detected between the perceived quality of sleep of the three diurnal sleep categories compared to the three nocturnal sleep categories. Even thought the nurses slept (napped) during the night shift,, their self-perceived alertness systematically decreased during it. Statistically significant differences were documented by one-way ANOVA (F = 40.534 p < .0001) among the alertness measurements done during the night shift. In particular, there was significant difference in the level of perceived alertness (p < .0001) between the 7(th) and 10(th)h of the 12h night shift. These findings of decreased alertness during the terminal hours of the night shift are of concern, since they suggest risk of comprised patient care.