Impairment of perceptual and motor abilities at the end of a night shift is greater in nurses working fast rotating shifts.

Objective: A three-shift work schedule with fast rotation is common among healthcare workers in Taiwan. This study compared cognitive performance at the time of maximum fatigue (3-4am on the last night shift of the rotation) between nurses working two, three, and four consecutive night shifts.

Methods: Sixty-two nurses [mean age 26.4 (standard deviation 2.0) years] were recruited from the acute psychiatric ward and assigned at random to three groups: two, three, and four consecutive night shifts. The exclusion criteria were: current use of hypnotic drugs, regular consumption of coffee, psychiatric illness, major systemic disease, and sleep disorders. Cognitive performance was assessed using the State-Trait Anxiety Inventory, Stanford Sleepiness Scale, Wisconsin Card Sorting Test, Taiwan University Attention Test, Digit Symbol Substitution Test, and Symbol Searching Test.

Results: Greater impairment of perceptual and motor ability was seen among subjects who worked two consecutive night shifts compared with those who worked four consecutive night shifts. No differences in demographic data, executive function or attention were found between the three groups.

Conclusion: The main duties of nurses working night shifts at the study hospital include checking medical orders and prescriptions, which require perceptual and motor abilities. The results of this study suggested that a fast shift rotation may increase the risk of medical errors.