The relationship between shift work, sleep, and cognition in career emergency physicians.
OBJECTIVE
The 24-hour physician coverage of the emergency department (ED) requires shift work, which can result in desynchronosis and cognitive decline. We measured changes in cognition and sleep disturbance in attending emergency physicians (EPs) before and after day and overnight shifts.


METHODS
Thirteen EPs were tested before and after day and overnight shifts using the Paced Auditory Serial Addition Test (PASAT), the University of Southern California Repeatable Episodic Memory Test (REMT), the Trail Making Test (TMT), and the Stroop Color-Word Test. Sleep quality and fatigue were assessed using the Pittsburgh Sleep Quality Index (PSQI) and Chalder Fatigue Questionnaire (CFQ). Saliva samples were collected from each physician immediately before and after day shifts and night shifts for neurohormonal assays.


RESULTS
Significantly fewer words were recalled on the REMT after both day (-2.4, 95% confidence interval [CI] = -4.4 to -0.4) and overnight shifts (-4.6, 95% CI = -6.4 to -2.8). There was a significant postshift increase in words recalled from the last third of the REMT list after overnight shifts (6.6, 95% CI = 2.8 to 10.4). Sleep quality was worse in EPs (mean PSQI = 4.8, SD ± 2.5) compared to the normal population, with 31% of subjects reporting poor sleep quality. Postshift fatigue was correlated with the perceived difficulty of the shift. Salivary cortisol and melatonin demonstrated diurnal variation consistent with normal circadian rhythms. Morning cortisol peak was decreased or delayed in samples from physicians after a night shift.


CONCLUSIONS
These data indicate that short-term memory appears to decline after day and overnight shifts and confirms the high incidence of disturbed sleep in this population.
Department of Emergency Medicine, Emergency Responder Human Performance Lab, University of Pittsburgh, Pittsburgh, PA, USA.
Mari S
MS
Machi
Matthew
M
Staum
Clifton W
CW
Callaway
Charity
C
Moore
Kwonho
K
Jeong
Joe
J
Suyama
P Daniel
PD
Patterson
David
D
Hostler
D000328:Adult; D002321:Career Choice; D002940:Circadian Rhythm; D003071:Cognition; D004635:Emergency Medicine; D005260:Female; D006801:Humans; D008297:Male; D008505:Medical Staff, Hospital / Q000523:psychology*; D011939:Mental Recall; D008875:Middle Aged; D009483:Neuropsychological Tests; D011446:Prospective Studies; D012893:Sleep Wake Disorders / Q000523:psychology*; D014940:Work Schedule Tolerance / Q000523:psychology*