The influence of shift work on the psychomotor capabilities of emergency medicine residents

Effect of serial night shifts on the cognitive, psychomotor, and moral performance of residents in the department of Emergency Medicine

OBJECTIVES

The objective was to study the effect of serial night shifts on the cognitive, psychomotor, and moral performance of emergency medicine residents of an academic Emergency Medicine Department.

METHODS

This prospective case-crossover study compared emergency medicine residents' sleep time, subjective sleepiness, cognitive function, moral judgment, and psychomotor skills after 5 consecutive days versus night shifts using sleep diaries, activity monitors, and multiple performance tests. Paired t-tests and Wilcoxon signed-rank tests were used to analyze data based on normality. Correlation analysis was done using Spearman's correlation test. Subgroup analysis was also performed to find any difference based on gender and year of residency.

RESULTS

Twenty-seven emergency medicine residents participated (13 males, 48.1%). The distribution across residency years was as follows: 44.4% in their first year, 25.9% in their second year, and 29.6% in their third year. Following five consecutive night shifts, total sleep duration decreased significantly from 338.1 ± 67.8 to 307.4 ± 71.0 min (p < 0.001), while subjective sleepiness scores increased from 9.6 ± 3.3 to 13.6 ± 4.6. Psychomotor performance and reaction times did not significantly differ between night and day shifts. However, working memory declined, assessed by self-paced three-back test scores (median [IQR] 517.1 [471.9-546.7] vs. 457.6 [334.4-508.8]; p = 0.034) and interference test scores (445.5 ± 59.9 vs. 407.2 ± 56.8; p < 0.001), along with moral judgment (median [IQR] 19 [18-28] vs. 15 [11-21]; p = 0.010) after serial night shifts. No correlations existed between performance measures nor differences based on gender or residency year.

CONCLUSIONS

Residents sleep less following night versus day shifts, reporting the highest sleepiness levels after 5 consecutive nights. Despite this, psychomotor performance and reaction times did not significantly differ. However, considerable reductions occurred in moral judgment, working memory, and interference test performance after serial night shifts.

Impact of sleep disturbance in shift workers on hippocampal volume and psychomotor speed

STUDY OBJECTIVES

Shift work interferes with circadian rhythms, affecting sleep quality and cognitive function. Poor sleep quality in shift worker (SW)s can impair psychomotor performance due to fatigue and sleepiness, increasing the risk of errors, accidents, and reduced productivity. Given the potential for atrophic changes in the hippocampus due to sleep disturbances, our study investigates how poor sleep quality correlates with hippocampal structural alterations and impacts psychomotor performance among SWs.

METHODS

We recruited 100 SWs, classifying them based on sleep quality into two groups: good sleep-SW group (n = 59) and poor sleep-SW group (n = 41). Sleep quality was assessed using both 7-day actigraphy for sleep efficiency and the Pittsburgh Sleep Quality Index. A control group of 106 non-SWs without sleep problems (non-SW group) was also included for comparison. The outcome measures were psychomotor speed and hippocampal volumes, both total and by subfield.

RESULTS

The poor sleep-SW group showed significantly smaller hippocampal volumes than both the good sleep-SW group (p < .001) and the non-SW group (p = .003). Longer shift work years correlated with greater reductions in hippocampal volume in this group (r = -0.42, p = .009), unlike in the good sleep-SW group (r = 0.08, p = .541). Furthermore, they demonstrated declines in psychomotor speed relative to the non-SW group (p = .006), which correlated with smaller hippocampal volumes (r = 0.37, p = .020).

CONCLUSIONS

SWs with poor sleep quality exhibit significant hippocampal volume reductions and psychomotor speed decline, underscoring the importance of early intervention and support for sleep issues in this population.

Emergency medicine resident productivity across consecutive shifts

Objectives

Clinical productivity is an important operational and educational metric for emergency medicine (EM) residents. It is unclear whether working consecutive days and circadian disruption impact resident productivity. The objective of this study was to determine whether there is a correlation between consecutive shifts and productivity.

Methods

This was a single-site retrospective observational study using data from academic year 2021-2022 (July 1, 2021-June 23, 2022). Productivity was defined as primary resident encounters with patients per hour (PPH). Postgraduate year (PGY)-1 and PGY-2 productivity data and schedules were abstracted from the electronic medical record and scheduling software. Descriptive statistics, including arithmetic mean, standard deviation, and confidence interval (CI), were determined for each shift number and stratified by PGY level. Subgroup analysis of night shifts was performed. Analysis of variance and linear regression analysis were performed.

Results

A total of 2950 shifts were identified, including 1328 PGY-1 shifts and 1622 PGY-2 shifts, which involved a total of 32,379 patient encounters. PGY-1 residents saw a mean of 0.88-0.96 PPH on sequential shifts 1-7, respectively (y-intercept 0.923, slope 0.001, 95% CI -0.008 to 0.009, p = 0.86). PGY-2 residents saw a mean of 1.61-1.75 PPH on Shifts 1-7, respectively (y-intercept 1.628, slope 0.004, 95% CI -0.007 to 0.015, p = 0.50). A subgroup analysis of 598 overnight shifts (11 p.m.-7 a.m.) was performed, in which residents saw a mean of 1.29-1.56 PPH on Sequential Shifts 1-7 (y-intercept 1.286, slope 0.011, 95% CI -0.011 to 0.033, p = 0.34).

Conclusions

EM resident productivity remained relatively constant across consecutive shifts, including night shifts. These findings may have educational and operational implications. Further research is required to understand patient- and provider-oriented consequences of consecutive shift scheduling.