Associations between number of consecutive night shifts and impairment of neurobehavioral performance during a subsequent simulated night shift

Excessive Daytime Sleepiness and Its Associated Factors among Emergency Medicine Residents in South Korea: A Nationwide Survey

Objective

Excessive daytime sleepiness (EDS) in emergency medicine (EM) residents is associated with patient safety. However, studies regarding EDS in EM residents are limited. The objective of this study was to identify the prevalence of EDS and its associated factors among EM residents.

Methods

Epworth sleepiness scale scores, working hours per week (WHW), night working days per month, working environment, and depression were analyzed using data from the 2019 Korean Emergency Medicine Resident Survey.

Results

The survey response rate was 63.8% (384/601). Among 241 respondents, the prevalence rate of EDS was 32.4%. Multivariable logistic regression analysis demonstrated that WHW (odds ratio [OR] = 1.03, 95% confidence interval [CI] = 1.01–1.06) and depression (OR = 3.64, 95% CI = 1.91–6.96) had increased ORs for EDS.

Conclusions

Approximately one-third of EM residents had EDS. Depression and WHW were the associated factors.

Chronotype-specific Sleep in Two Versus Four Consecutive Shifts

The study aimed to explore chronotype-specific effects of two versus four consecutive morning or night shifts on sleep-wake behavior. Sleep debt and social jetlag (a behavioral proxy of circadian misalignment) were estimated from sleep diary data collected for 5 weeks in a within-subject field study of 30 rotating night shift workers (29.9 ± 7.3 years, 60% female). Mixed models were used to examine whether effects of shift sequence length on sleep are dependent on chronotype, testing the interaction between sequence length (two vs. four) and chronotype (determined from sleep diaries). Analyses of two versus four morning shifts showed no significant interaction effects with chronotype. In contrast, increasing the number of night shifts from two to four increased sleep debt in early chronotypes, but decreased sleep debt in late types, with no change in intermediate ones. In early types, the higher sleep debt was due to accumulated sleep loss over four night shifts. In late types, sleep duration did not increase over the course of four night shifts, so that adaptation is unlikely to explain the observed lower sleep debt. Late types instead had increased sleep debt after two night shifts, which was carried over from two preceding morning shifts in this schedule. Including naps did not change the findings. Social jetlag was unaffected by the number of consecutive night shifts. Our results suggest that consecutive night shifts should be limited in early types. For other chronotypes, working four night shifts might be a beneficial alternative to working two morning and two night shifts. Studies should record shift sequences in rotating schedules.

Association between chronotype and psychomotor performance of rotating shift workers

It is known that the chronotype potentially mediates the performance and tolerance to work in shifts and that shift rotation is associated with negative effects on psychomotor performance. This study aimed to evaluate the effect of chronotype on psychomotor performance throughout a complete shift rotation schedule. Thirty males working in clockwise rotating shifts from a mining company were evaluated under a real-life condition over the following shift schedule: 2 days of day work, 2 days of evening work and 2 days of night work. The chronotype was determined using the Munich Chronotype Questionnaire adapted for shift workers and the obtained scores were categorized by tertiles (early-type, intermediate-type and late-type). Work performance was evaluated by Psychomotor Vigilance Test (PVT) daily just before shift starts and after shift ends. Sleep duration was evaluated by actigraphy over the whole shift. No isolated effect of the shift or interaction between shift and chronotype was found in the performance variables evaluated. A significant isolated effect of the chronotype showed that the early-type individuals had higher values of pre- and post-work Mean of Reaction Time (MRT) (308.77 ± 10.03 ms and 306.37 ± 8.53 ms, respectively) than the intermediate-type (257.61 ± 6.63 ms and 252.91 ± 5.97 ms, respectively, p < 0.001) and the late-type (273.35 ± 6.96 ms and 262.88 ± 6.05 ms, respectively, p < 0.001). In addition, late individuals presented a greater number of lapses of attention (5.00 ± 0.92; p < 0.05) than early (1.94 ± 0.50, p < 0.05) and intermediate (1.33 ± 0.30, p < 0.001) ones. We concluded that, compared with intermediates, late-type workers had a greater number of lapses of attention on the shift schedule as a whole, while early-type workers showed the highest pre- and post-work MRT. These findings show that the psychomotor performance of rotating shift workers seems to be influenced by the chronotype, but not by the shift rotation.

Quality use of diagnostic imaging in trauma, and the impact on emergency medical practice-a retrospective clinical audit

PURPOSE

The current study aimed to evaluate the appropriateness of the decisions made to order diagnostic imaging for emergency trauma patients.

METHODS

A retrospective audit of 642 clinical decisions for 370 non-consecutive trauma cases was conducted at a level 1 adult trauma centre. Radiographs and computed tomography investigations were compared for compliance with the American College of Radiology/European Society of Radiology (ACR/ESR) imaging guidelines. The non-compliant imaging orders were evaluated for the following medical officer ranks: Junior Medical Officer (JMO), Senior Resident Medical Officer (SRMO), Emergency Medicine Registrar (EMR) and Consultants/Career Medical Officer (CMO). The time of imaging order (day/evening or night shift), whether the imaging led to conservative or surgical patient management, and whether the imaging order decisions led to a change in the clinical management of the patient were also considered.

RESULTS

Non-compliance with the ACR/ESR guidelines was low. At least half of non-compliant decisions made by each level of medical officer resulted in a change in patient management. In total, 11 (65%), 25 (53%), 12 (63%) and 11 (52%) of non-compliant imaging orders placed by JMOs, SRMOs, EMRs and Consultants, respectively, resulted in change of patient management. JMOs and SRMOs ordered a significantly higher proportion of non-compliant imaging studies for conservatively managed patients in comparison to surgically managed patients.

CONCLUSION

This study highlighted that most non-compliant imaging orders benefited the patient.

Subjective and objective assessments after a change from a 4-crew, 12-h shift to a 3-crew, 12-h shift schedule: an observational study

PURPOSE

To clarify the subjective and objective impacts of a change in a 12-h shift schedule, involving a reduction in the number of crews, on workers at an electronic parts production company.

METHODS

Forty-two workers participated in this study. Subjective indicators (e.g. questionnaires) and objective indicators [e.g., psychomotor vigilance task (PVT)], as well as an activity monitor-based sleep assessment, were measured during a > 1-year period that encompassed the shift schedule change. The study outcome was a comparison of work-related injury rates measured 1 year before and after the change in shift schedule.

RESULTS

After the shift schedule change, questionnaire scores regarding work-related burdens and PVT performance parameters, including mean response time and number of lapses, increased significantly. However, we also observed divergences in the trends of the subjective and objective measures 1 year after the change. Despite these variations in both types of measures, we observed no significant differences in work-related injury rates measured before and after the shift schedule change.

CONCLUSION

This study revealed that a reduction in the number of crews in a 12-h shift schedule has a negative impact on the subjective and objective indicator after the change in shift schedule; only indicators of alertness did not recover at 1 year after the change. Assessments of the workers' performances and the regular implementation of health and safety programs for more than 1 year are needed to maintain workers' health after the change in shift schedule.

Shift rotation, circadian misalignment and excessive body weight influence psychomotor performance: a prospective and observational study under real life conditions

We aimed to evaluate the influence of shift work rotation, circadian misalignment and being overweight/obese on psychomotor performance throughout a complete shift rotation schedule. The study was conducted with 30 males working rotating shifts from a mining company under real life conditions. Individuals were evaluated over seven days in a shift schedule carried out as follow: two shifts in the morning (D1 and D2), two shifts in the afternoon (D3 and D4), 24 hour free day (D5) and two shifts at night (D6 and D7). Work performance was evaluated by psychomotor vigilance task tests (PVT), and actigraphy was used to characterise the rest-activity rhythm based on intradaily variability (IV) and interdaily stability (IS) of nonparametric functions. We found a significant effect of the shift, body mass index (BMI), IS and IV on lapses in attention. More lapses occurred on D7 than D1, D2, D3 and D4 of the schedule shift. The obese group presented a higher number of lapses in attention than eutrophic. The interaction between day and IS showed that less synchronised individuals presented a higher number of lapses in attention on D7 than D1 and, for the interaction between day and IV, more fragmented individuals presented a higher number of lapses in attention on D7 than D6. We conclude that higher BMI, lower synchronisation and higher fragmentation of the rest-activity pattern influenced lapses in attention throughout the shift rotation.

The Impact of Shift Work on Sleep, Alertness and Performance in Healthcare Workers

Shift work is associated with impaired alertness and performance due to sleep loss and circadian misalignment. This study examined sleep between shift types (day, evening, night), and alertness and performance during day and night shifts in 52 intensive care workers. Sleep and wake duration between shifts were evaluated using wrist actigraphs and diaries. Subjective sleepiness (Karolinska Sleepiness Scale, KSS) and Psychomotor Vigilance Test (PVT) performance were examined during day shift, and on the first and subsequent night shifts (3^rd, 4^th or 5^th). Circadian phase was assessed using urinary 6-sulphatoxymelatonin rhythms. Sleep was most restricted between consecutive night shifts (5.74 ± 1.30 h), consecutive day shifts (5.83 ± 0.92 h) and between evening and day shifts (5.20 ± 0.90 h). KSS and PVT mean reaction times were higher at the end of the first and subsequent night shift compared to day shift, with KSS highest at the end of the first night. On nights, working during the circadian acrophase of the urinary melatonin rhythm led to poorer outcomes on the KSS and PVT. In rotating shift workers, early day shifts can be associated with similar sleep restriction to night shifts, particularly when scheduled immediately following an evening shift. Alertness and performance remain most impaired during night shifts given the lack of circadian adaptation to night work. Although healthcare workers perceive themselves to be less alert on the first night shift compared to subsequent night shifts, objective performance is equally impaired on subsequent nights.

Work and Health Correlates of Sleep Quantity and Quality Among Correctional Nurses

BACKGROUND/OBJECTIVES

The correctional environment exposes nurses to unique physical and psychosocial work stressors, such as inmate violence and safety concerns. Nurses often experience short and poor sleep; however, the quantity and quality of sleep in this specialty practice group of nurses are underexplored. The study objective was to examine a wide range of work and health correlates of sleep quantity and quality in correctional nurses.

METHODS

A Web-based survey was administered to nurses within a Northeastern State Correctional Healthcare System, covering questions on sleep quantity and quality, working conditions, health outcomes, and work outcomes.

RESULTS

Among the 89 correctional nurses who participated, 56.2% reported short sleep duration (≤6 hours/day) and 31.8% reported poor sleep quality. Multivariate Poisson regression modeling suggested that night shift (prevalence ratio [PR] = 1.95, p < 0.05) and single marital status (PR = 2.25, p < 0.05) were significantly associated with increased prevalence of short sleep duration, whereas none of the work and health variables were significantly associated with increased prevalence of poor sleep quality, after adjustment for sociodemographics and other covariates.

CONCLUSION

Correctional nurses experience a high prevalence of short and poor sleep. Similar to previous studies, we found that short sleep duration was associated with night shift work. Interventions targeting work schedule remodeling (e.g., reduce the number of consecutive night shifts) and shift work coping mechanisms may promote sleep health of correctional nurses.

The Clinical Biology of Cystic Fibrosis Transmembrane Regulator Protein: Its Role and Function in Extrapulmonary Disease

Normal cystic fibrosis (CF) transmembrane regulator (CFTR) protein has multiple functions in health and disease. Many mutations in the CFTR gene produce abnormal or absent protein. CFTR protein dysfunction underlies the classic CF phenotype of progressive pulmonary and GI pathology but may underlie diseases not usually associated with CF. This review highlights selected extrapulmonary disease that may be associated with abnormal CFTR. Increasing survival in CF is associated with increasing incidence of diseases associated with aging. CFTR dysfunction in older individuals may have novel effects on glucose metabolism, control of insulin release, regulation of circadian rhythm, and cancer cell pathophysiology. In individuals who have cancers with acquired CFTR suppression, their tumors may more likely exhibit rapid expansion, epithelial-to-mesenchymal transformation, abnormally reduced apoptosis, and increased metastatic potential. The new modulators of CFTR protein synthesis could facilitate the additional exploration needed to better understand the unfolding clinical biology of CFTR in human disease, even as they revolutionize treatment of patients with CF.

Daily circadian misalignment impairs human cognitive performance task-dependently

Shift work increases the risk for human errors, such that drowsiness due to shift work has contributed to major industrial disasters, including Space Shuttle Challenger, Chernobyl and Alaska Oil Spill disasters, with extraordinary socio-economical costs. Overnight operations pose a challenge because our circadian biology inhibits cognitive performance at night. Yet how the circadian system modulates cognition over multiple days under realistic shift work conditions remains to be established. Importantly, because task-specific cognitive brain regions show different 24-h circadian dynamics, we hypothesize that circadian misalignment impacts cognition task-dependently. Using a biologically-driven paradigm mimicking night shift work, with a randomized, cross-over design, we show that misalignment between the circadian pacemaker and behavioral/environmental cycles increases cognitive vulnerability on sustained attention, cognitive throughput, information processing and visual-motor performance over multiple days, compared to circadian alignment (day shifts). Circadian misalignment effects are task-dependent: while they acutely impair sustained attention with recovery after 3-days, they progressively hinder daily learning. Individuals felt sleepier during circadian misalignment, but they did not rate their performance as worse. Furthermore, circadian misalignment effects on sustained attention depended on prior sleep history. Collectively, daily circadian misalignment may provide an important biological framework for developing countermeasures against adverse cognitive effects in shift workers.

The viability of an ecologically valid chronic sleep restriction and circadian timing protocol: An examination of sample attrition, compliance, and effectiveness at impacting sleepiness and mood

Chronic sleep restriction (SR) increases sleepiness, negatively impacts mood, and impairs a variety of cognitive performance measures. The vast majority of work establishing these effects are tightly controlled in-lab experimental studies. Examining commonly-experienced levels of SR in naturalistic settings is more difficult and generally involves observational methods, rather than active manipulations of sleep. The same is true for analyzing behavioral and cognitive outcomes at circadian unfavorable times. The current study tested the ability of an at-home protocol to manipulate sleep schedules (i.e., impose SR), as well as create a mismatch between a subject's circadian preference and time of testing. Viability of the protocol was assessed via completion, compliance with the SR, and success at manipulating sleepiness and mood. An online survey was completed by 3630 individuals to assess initial eligibility, 256 agreed via email response to participate in the 3-week study, 221 showed for the initial in-person session, and 184 completed the protocol (175 with complete data). The protocol consisted of 1 week at-home SR (5-6 hours in bed/night), 1 week wash-out, and 1 week well-rested (WR: 8-9 hours in bed/night). Sleep was monitored with actigraphy, diary, and call-ins. Risk management strategies were implemented for subject safety. At the end of each experimental week, subjects reported sleepiness and mood ratings. Protocol completion was 83%, with lower depression scores, higher anxiety scores, and morning session assignment predicting completion. Compliance with the sleep schedule was also very good. Subjects spent approximately 2 hours less time in bed/night and obtained an average of 1.5 hours less nightly sleep during SR, relative to WR, with 82% of subjects obtaining at least 60 minutes less average nightly sleep. Sleepiness and mood were impacted as expected by SR. These findings show the viability of studying experimental chronic sleep restriction outside the laboratory, assuming appropriate safety precautions are taken, thus allowing investigators to significantly increase ecological validity over strictly controlled in-lab studies.