Consecutive Shifts Research Articles

Bilinear branch and check for unspecified parallel machine scheduling with shift consideration

This paper tackles the complex challenge of team formations, assignments, and job schedules within the static Unspecified Parallel Machine Flexible Resource Scheduling problem, specifically incorporating shift considerations. In existing literature, teams are often simplified as machines that operate continuously throughout the day without any interruptions. However, in reality, teams require breaks between shifts and cannot work continuously within a day. Therefore, we introduce shift considerations to ensure that teams do not work in consecutive shifts. We consider flexible workers, capable of performing any job, who are distributed among different teams in different shifts to undertake various jobs. The number of teams in each shift is a decision variable. The duration of each job is determined by the number of workers in a team assigned to it. The objective function is to minimize the makespan, representing the overall schedule completion time, while adhering to precedence constraints. We formulate an integer linear programming model for the proposed problem and develop a novel bilinear branch and check algorithm that introduces valid bilinear inequalities to accelerate convergence. The numerical results confirm that our algorithm’s performance optimally solves problems up to 35 jobs within a reasonable timeframe, surpassing the efficiency of the branch and cut method of IBM CPLEX and the classical branch and check algorithm.

Optimal Network Design for Municipal Waste Management: Application to the Metropolitan City of Rome

This work is part of the regional research project PIPER—Intelligent Platform for the Optimization of Recycling Operations, which aims to develop a network design model for waste collection in the metropolitan city of Rome, Italy. The goal is to enhance the strategic planning of treatment and disposal facilities by incorporating transshipment locations to improve the efficiency of waste collection. The motivation for this study stems from the stringent targets set by the European Green Deal to achieve near-zero emissions and the critical role of waste management in realizing circular economy practices. Methods: The problem is formulated as a mixed integer linear program (MILP) that includes constraints on vehicle allocation to shifts and driver requirements. An additional feature of the model is its ability to account for vehicle maintenance issues when deployed on consecutive shifts. Results: The model was tested against a real-world case study in Rome and demonstrated significant potential savings, with a reduction in total traveled distance exceeding 10%. The mathematical model was also used for evaluating strategic scenarios in a “what-if” analysis, allowing the municipal collection company to assess location options for depots, waste treatment facilities, and transshipment points, as well as to optimize the fleet composition and driver allocation during work shifts. Conclusions: This study presents a robust tool for strategic planning in waste collection operations, highlighting the benefits of using transshipment locations to improve efficiency. The findings indicate substantial potential for cost savings and operational improvements, making the model a valuable asset for municipal waste management planning.

Effects of night-float shifts on cognitive function among radiology residents

BackgroundMany radiology programs utilize a night-float system to mitigate the effects of fatigue, improve patient care, and provide faster report turnaround times. Prior studies have demonstrated an increase in discrepancy rates during night-float shifts.ObjectivesThis study was performed to examine the effects of night-float shift work on radiology resident cognition. We hypothesized that there would be diminished cognitive function on testing following night-float shifts when compared to testing following day shifts.MethodsDiagnostic radiology residents in their second to fifth years of residency at a single institution were recruited to participate in this pilot study. Cognitive function was evaluated using the Lumosity Neurocognitive Performance Tests (NCPT), standardized performance tests that provide real-time, objective measurements of cognitive function. Study participants completed the NCPT in 5 sessions following 5 consecutive day shifts to evaluate their baseline cognitive function. The tests were re-administered at the end of consecutive night-float shifts to assess for any changes. Sleep was objectively monitored using actigraphy devices worn around the wrist during all study weeks. Descriptive and summary statistics were performed.Results23 prospectively recruited diagnostic radiology residents working night-float shifts took a mean 13.6 (± 5.1) neurocognitive performance tests during the study period. There was a statistically significant decline in 2 of the 6 cognitive tests administered, signifying a decrease in attention, speed, and complex reasoning ability. Night-float shifts were significantly longer than the day shifts and associated with a significantly higher study volume and cross-sectional study volume. Fitbit data demonstrated that there were no significant differences in level of activity while awake. However, participants slept significantly longer during day shifts.ConclusionsA sample of 23 radiology residents working night-float shifts demonstrated declines in attention, speed, and complex reasoning ability following sequential administration of standardized neurocognitive performance tests. While the sample size is small, these findings demonstrate the potential deleterious effects of night-float shift work and provide evidence to support further inquiry into this phenomenon.

Sleep duration and quality in permanent night work: an observational field study

PurposePermanent night workers conceivably show better adaptation of circadian rhythms to night work than shift workers and therefore better possibilities of obtaining sufficient sleep of good quality after night shifts. We investigated the effect of night shifts including number of consecutive shifts on sleep among self-selected permanent night workers, and studied if the effect of night shifts differed between morning and evening types and compared with 3-shift workers.MethodsThe study population included 90 permanent night workers followed for 14 days (warehouse workers, 1228 observation days, 80% males). For comparison, we included 70 3-shift workers followed for 26 days (police officers, 1774 observation days, 100% men). Total sleep time (TST), primary sleep duration (PSD), and sleep efficiency were assessed by actigraphy. Measures of sleep quality and diurnal type were self-reported.ResultsAmong permanent night workers, TST, PSD, difficulties falling asleep, disturbed sleep, and the number of awakenings decreased after night shifts compared with days without night work. Sleep efficiency, difficulties awakening, and non-refreshing sleep increased. More consecutive night shifts were associated with shorter TST and PSD. Sleep outcomes did not differ by diurnal type. Permanent night workers had fewer awakenings after night shifts than 3-shift workers, but no other differences were observed.ConclusionThis study does not provide evidence that supports recommendation of permanent night work to reduce adverse effects of night shifts on sleep. A limited number of consecutive night shifts is recommended to reduce accumulation of sleep debt.

Burnout in emergency physicians in Hong Kong—A cross‐sectional study on its prevalence, associated factors, and impact

AbstractObjectiveTo evaluate the prevalence of burnout, its underlying personal or occupational stressors, and impact on individual well‐being and patient care.DesignCross‐sectional survey.ParticipantsAll emergency physicians in the public and the private sector in Hong Kong.MethodSelf‐administered, anonymous, voluntary questionnaires were distributed in physical and electronic forms from April to June 2022. Burnout was assessed by the Maslach Burnout Inventory (MBI). Stressors were assessed by questions on demographic, occupational, and social background. Impact was assessed by the Patient Health Questionnaire‐9 (PHQ‐9) for depression and questions on job satisfaction and self‐perceived patient care.ResultsThe response rate was 37.8% (n = 241). Prevalence of high overall burnout was 28.2% (n = 68), with 47.7% (n = 115) having high emotional exhaustion, 63.1% (n = 152) high depersonalization, and 56% (n = 135) low personal accomplishment. A higher burnout rate was observed in younger age, female, not married, job position (associate consultant, resident specialist, and higher trainee), working on shift duty, more night shifts, and consecutive shifts. Burnout is also associated with depression, suicidal idea, consideration of quitting, less job satisfaction, and less favorable patient care (p < 0.05).ConclusionBurnout is prevalent in emergency physicians in Hong Kong, and its impact on individual well‐being and clinical care was evident. A higher burnout rate was observed in younger doctors and also fellows. Identified stressors such as shift pattern should be addressed and potentially improved. Further strategies should be explored to reduce burnout in our colleagues.

Investigation of the Relationship among Work Shift, Sleep Quality, and Work Ability Index in Pre-Hospital Emergency Personnel in Urmia City in 2023

Objectives: Nowadays, due to the increase in the volume of accidents, pre-hospital emergency personnel, as the frontline of treatment by providing relief and assistance to patients and victims of various incidents, have encountered various work-related challenges and problems, including cardiovascular diseases, digestive diseases, excessive fatigue, and reduced sleep quality. In this regard, the present research aimed to study the relationship among shift work, sleep quality, and work ability index in pre-hospital emergency personnel. Methods: This research was performed on 102 operational personnel of a pre-hospital emergency department in Urmia, Iran. After the collection of demographic information, the number of work shifts per week, the number of working hours per month, the quality of sleep, and the work ability of the personnel were measured by the Petersburg sleep quality questionnaire and work ability index questionnaire. The relationship between research variables was investigated using correlation coefficient, Fisher's exact test, and one-way analysis of variance tests. Results: Mean total sleep quality score of the personnel was 6.01 ± 2.38, which indicated poor and unfavorable sleep quality. Moreover, work ability index scores of 34.3%, 52%, and 13.7% of participants were at poor, moderate, good, and excellent levels, respectively. Regarding the comparison between the two variables of shift work and sleep quality, there was a significant difference, and a strong and significant relationship was observed between sleep quality and work ability index. Conclusion: Through the increase in the number of work shifts and working hours, the sleep quality of the personnel became unfavorable and weak which led to a decrease in the work ability index score and a reduction in the job performance of the personnel. Reduction of working hours, usage of young people with high work ability, management and control of the number of work shifts of the personnel by considering resting and closure time, consideration of morning-evening and night shifts in a balanced and equal manner, and prevention of people from working in monotonous shifts (activity only in the form of night work or only day work), and avoidance of working in consecutive work shifts without rest and vacation in order to improve the quality of sleep and work performance is recommended.

Simulated quick returns in a laboratory context and effects on sleep and pre-sleep arousal between shifts: a crossover controlled trial

This trial presents a laboratory model investigating the effect of quick returns (QRs, <11 h time off between shifts) on sleep and pre-sleep arousal. Using a crossover design, 63 participants worked a simulated QR condition (8 h time off between consecutive evening- and day shifts) and a day-day (DD) condition (16 h time off between consecutive day shifts). Participants slept at home and sleep was measured using a sleep diary and sleep radar. Compared to the DD condition, the QR condition reduced subjective and objective total sleep time by approximately one hour (both p < .001), reduced time in light- (p < .001), deep- (p = .004), rapid eye movement (REM, p < .001), percentage of REM sleep (p = .023), and subjective sleep quality (p < .001). Remaining sleep parameters and subjective pre-sleep arousal showed no differences between conditions. Results corroborate previous field studies, validating the QR model and indicating causal effects of short rest between shifts on common sleep parameters and sleep architecture.

Rapid and cost-effective molecular karyotyping in wheat, barley, and their cross-progeny by chromosome-specific multiplex PCR

BackgroundInterspecific hybridisation is a powerful tool for increasing genetic diversity in plant breeding programmes. Hexaploid wheat (Triticum aestivum, 2n = 42) × barley (Hordeum vulgare, 2n = 14) intergeneric hybrids can contribute to the transfer of agronomically useful traits by creating chromosome addition or translocation lines as well as full hybrids. Information on the karyotype of hybrid progenies possessing various combinations of wheat and barley chromosomes is thus essential for the subsequent breeding steps. Since the standard technique of chromosome in situ hybridisation is labour-intensive and requires specific skills. a routine, cost-efficient, and technically less demanding approach is beneficial both for research and breeding.ResultsWe developed a Multiplex Polymerase Chain Reaction (MPCR) method to identify individual wheat and barley chromosomes. Chromosome-specific primer pairs were designed based on the whole genome sequences of ‘Chinese Spring’ wheat and ‘Golden Promise’ barley as reference cultivars. A pool of potential primers was generated by applying a 20-nucleotide sliding window with consecutive one-nucleotide shifts on the reference genomes. After filtering for optimal primer properties and defined amplicon sizes to produce an ordered ladder-like pattern, the primer pool was manually curated and sorted into four MPCR primer sets for the wheat A, B, and D sub-genomes, and for the barley genome. The designed MPCR primer sets showed high chromosome specificity in silico for the genome sequences of all 18 wheat and barley cultivars tested. The MPCR primers proved experimentally also chromosome-specific for the reference cultivars as well as for 13 additional wheat and four barley genotypes. Analyses of 16 wheat × barley F1 hybrid plants demonstrated that the MPCR primer sets enable the fast and one-step detection of all wheat and barley chromosomes. Finally, the established genotyping system was fully corroborated with the standard genomic in situ hybridisation (GISH) technique.ConclusionsWheat and barley chromosome-specific MPCR offers a fast, labour-friendly, and versatile alternative to molecular cytogenetic detection of individual chromosomes. This method is also suitable for the high-throughput analysis of distinct (sub)genomes, and, in contrast to GISH, can be performed with any tissue type. The designed primer sets proved to be highly chromosome-specific over a wide range of wheat and barley genotypes as well as in wheat × barley hybrids. The described primer design strategy can be extended to many species with precise genome sequence information.

Emergency medicine resident productivity across consecutive shifts.

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. 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. 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). 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.

Incidence of Fit Test Failure During N95 Respirator Reuse and Extended Use

The COVID-19 pandemic resulted in a widespread acute shortage of N95 respirators, prompting the Centers for Disease Control and Prevention to develop guidelines for extended use and limited reuse of N95s for health care workers (HCWs). While HCWs followed these guidelines to conserve N95s, evidence from clinical settings regarding the safety of reuse and extended use is limited. To measure the incidence of fit test failure during N95 reuse and compare the incidence between N95 types. This prospective cohort study, conducted from April 2, 2021, to July 15, 2022, at 6 US emergency departments (EDs), included HCWs who practiced N95 reuse for more than half of their clinical shift. Those who were unwilling to wear an N95 for most of their shift, repeatedly failed baseline fit testing, were pregnant, or had facial hair or jewelry that interfered with the N95 face seal were excluded. Wearing the same N95 for more than half of each clinical shift and for up to 5 consecutive shifts. Participants chose an N95 model available at their institution; models were categorized into 3 types: dome (3M 1860R, 1860S, and 8210), trifold (3M 1870+ and 9205+), and duckbill (Halyard 46727, 46767, and 46827). Participants underwent 2 rounds of testing using a different mask of the same type for each round. The primary outcome was Occupational Safety and Health Administration-approved qualitative fit test failure. Trained coordinators conducted fit tests after clinical shifts and recorded pass or fail based on participants tasting a bitter solution. A total of 412 HCWs and 824 N95s were fit tested at baseline; 21 N95s (2.5%) were withdrawn. Participants' median age was 34.5 years (IQR, 29.5-41.8 years); 252 (61.2%) were female, and 205 (49.8%) were physicians. The overall cumulative incidence of fit failure after 1 shift was 38.7% (95% CI, 35.4%-42.1%), which differed by N95 type: dome, 25.8% (95% CI, 21.2%-30.6%); duckbill, 28.3% (95% CI, 22.2%-34.7%); and trifold, 61.3% (95% CI, 55.3%-67.3%). The risk of fit failure was significantly higher for trifold than dome N95s (adjusted hazard ratio, 1.75; 95% CI, 1.46-2.10). In this cohort study of ED HCWs practicing N95 reuse, fit failure occurred in 38.7% of masks after 1 shift. Trifold N95s had higher incidence of fit failure compared with dome N95s. These results may inform pandemic preparedness, specifically policies related to N95 selection and reuse practices.

Pengaruh Beban Kerja Terhadap Kinerja Karyawan Di Hotel Plataran Bromo

The inspiration for this study arises from various challenges, including a workload that sometimes feels overwhelming, frequent breakdowns in communication during task handling, and employees having to adapt to consecutive shifts. The primary aim of this research is to assess the impact of workload on the performance of Plataran Bromo Hotel employees. Employing a quantitative approach with a causal associative method, the study utilizes both primary and secondary data. The participants consist of the workforce at Plataran Bromo Hotel, and data collection involves a validated survey with a Likert scale. The gathered information undergoes analysis using SPSS 27.00. The findings reveal that the workload is categorized as "quite good" (32.2%), while Employee Performance falls under the "good" category (60%). The research indicates a significant correlation between Workload and Employee Performance, with an R-squared value of 0.172, demonstrating significance at 0.000 &lt; 0.05. This implies that 0.828 is influenced by other contributing factors. Additionally, a regression coefficient of 0.618, significant at 0.000 &lt; 0.05, suggests that a one-unit increase in Workload corresponds to a 0.618-unit increase in Employee Performance. Consequently, Workload exhibits a positive and noteworthy impact on Employee Performance.

Circadian Adaptation of Melatonin and Cortisol in Police Officers Working Rotating Shifts.

Misalignment of behavior and circadian rhythms due to night work can impair sleep and waking function. While both simulated and field-based studies suggest that circadian adaptation to a nocturnal schedule is slow, the rates of adaptation in real-world shift-work conditions are still largely unknown. The aim of this study was to evaluate the extent of adaptation of 24-h rhythms with 6-sulfatoxymelatonin (aMT6s) and cortisol in police officers working rotating shifts, with a special attention to night shifts. A total of 76 police officers (20 women; aged 32 ± 5.4 years, mean ± SD) from the province of Quebec, Canada, participated in a field study during their 28- or 35-day work cycle. Urine samples were collected for ~32 h before a series of day, evening, and night shifts to assess circadian phase. Before day, evening, and night shifts, 60%-89% of officers were adapted to a day schedule based on aMT6 rhythms, and 71%-78% were adapted based on cortisol rhythms. To further quantify the rate of circadian adaptation to night shifts, initial and final phases were determined in a subset of 37 officers with suitable rhythms for both hormones before and after 3-8 consecutive shifts (median = 7). Data were analyzed with circular and linear mixed-effects models. After night shifts, 30% and 24% of officers were adapted to a night-oriented schedule for aMT6s and cortisol, respectively. Significantly larger phase-delay shifts (aMT6s: -7.3 ± 0.9 h; cortisol: -6.3 ± 0.8 h) were observed in police officers who adapted to night shifts than in non-adapted officers (aMT6s: 0.8 ± 0.9 h; cortisol: 0.2 ± 1.1 h). Consistent with prior research, our results from both urinary aMT6s and cortisol midpoints indicate that a large proportion of police officers remained in a state of circadian misalignment following a series of night shifts in dim-light working environments.

Doctors’ alertness, contentedness and calmness before and after night shifts: a latent profile analysis

BackgroundWhile night shifts are crucial for patient care, they threaten doctors’ well-being and performance. Knowledge of how the impact of night shifts differs for doctors is needed to attenuate the adverse effects of night shifts. This study aimed to obtain more precise insight into doctors’ feelings surrounding night shift by: identifying profiles based on doctors’ alertness, contentedness and calmness scores before and after night shifts (research question (RQ) 1); assessing how doctors’ pre- and post-shift profiles change (RQ2); and determining associations of doctors’ demographics and shift circumstances with alertness, contentedness and calmness change (RQ3).MethodsLatent Profile Analysis using doctors’ pre- and post-shift self-rated alertness, contentedness and calmness scores was employed to identify pre- and post-shift profiles (RQ1). A cross-tabulation revealed pre- and post-shift profile changes (RQ2). Multiple regressions determined associations of demographics (i.e. age, sex, specialty) and night shift circumstances (i.e. hours worked pre-call, hours awake pre-call, shift duration, number of consecutive shifts, total hours of sleep) with alertness, contentedness and calmness change (RQ3).ResultsIn total, 211 doctors participated with a mean age of 39.8 ± 10 years; 47.4% was male. The participants included consultants (46.4%) and trainees (53.6%) of the specialties surgery (64.5%) and obstetrics/gynaecology (35.5%). Three pre-shift (Indifferent, Ready, Engaged) and four post-shift profiles (Lethargic, Tired but satisfied, Excited, Mindful) were found. Most doctors changed from Ready to Tired but satisfied, with alertness reducing most. Age, specialty, sleep, shift duration and the number of consecutive shifts associated with alertness, contentedness and calmness changes.ConclusionsThe results provided nuanced insight into doctors’ feelings before and after night shifts. Future research may assess whether specific subgroups benefit from tailored interventions.

Consecutive Shifts: A Repeated Measure Study to Evaluate Stress, Biomarkers, Social Support, and Fatigue in Medical/Surgical Nurses.

Nurses report that they are required to work during their scheduled breaks and generally experience extended work times and heavy workloads due to staffing shortages. This study aimed to examine changes in personal, work-related, and overall stress, as well as biological responses and fatigue experienced by nurses during three consecutive 12 h workdays (i.e., the typical "three-twelves" schedule). We also considered the moderating effects of social resources. This prospective study of 81 medical/surgical nurses who completed questionnaires and provided saliva samples at four designated intervals (i.e., pre-shift and post-shift on workdays 1 and 3). Fatigue reported by night shift nurses increased significantly over three consecutive workdays (p = 0.001). Day shift nurses said they encountered more social support than those on the night shift (p = 0.05). Social support moderated the relationship between work-related stress at baseline and reported fatigue on day 3.

The effect of Aromatherapy with Pelargonium graveolens (P. graveolens) on the fatigue and sleep quality of critical care nurses during the Covid-19 pandemic: A randomized controlled trial

ObjectivesMeasures to reduce nurses' fatigue are necessary to improve the patient's care and the nurse's health and well-being. This study investigated the effectiveness of aromatherapy with Pelargonium graveolens (P. graveolens) essential oil on fatigue and sleep quality of nurses working in intensive care units (ICU). MethodsIn this double-blind, randomized, controlled clinical trial, 84 nurses working in the ICU of Covid-19 patients were assigned to two groups of P. graveolens and placebo by the stratified block method. The intervention group inhaled one drop of pure P. graveolens. The placebo group inhaled one drop of pure sunflower oil in three consecutive shifts (morning or evening) and each shift twice for 20 min. Using the Visual Analog Fatigue Scale (VAS-F), fatigue was measured 30 min before the intervention, immediately, and 60 min later. Also, on the morning of the intervention days, sleep quality was assessed with the Verran and Snyder-Halpern (VSH) Sleep Scale. Data analysis was performed using SPSS, version 24. Independent t-tests, Mann-Whitney, Chi-square tests, and MANOVA, were used. ResultsThe mean score of fatigue immediately and 60 min after aromatherapy in the P. graveolens group was lower than in the control group (P ˂ 0.05). There was no significant difference between the mean sleep scores of nurses in the P. graveolens group before and after the intervention (P > 0.05). ConclusionInhalation aromatherapy with P. graveolens essential oil can reduce nurses' fatigue in the ICU. The findings of this study can make nurses interested in using aromatherapy as a self-care method.

0249 Individual differences of sleep pattern and duration between two consecutive night shifts among night workers

Abstract Introduction Working at night leads to shortened and disturbed daytime sleep. Night workers usually adopt one of several sleep patterns between consecutive nights: sleeping right after night work (morning sleep), delaying sleep to the afternoon (afternoon sleep), or dividing sleep into two or more episodes (split sleep). However, few studies have examined sleep pattern and duration between consecutive nights in real-world workers. The objective of this study was to examine individual differences in sleep pattern and duration when working consecutive night shifts. Methods Night workers (n=241, 43.0±16.5y, 67.2% female) from various occupations who reported working consecutive nights completed an online survey. The survey included questions on socio-demographics and daytime sleep and nap schedules. Sleep pattern (morning vs. afternoon vs. split) and total sleep time (sleep+naps) were derived from survey responses. Cross-tabulations and ANOVA were conducted. Results On average, night workers reported a total daytime sleep of 5.37±2.69 hours (range 0-14.25 hours). 65.1% reported morning sleep, 10% afternoon sleep, and 24.9% split sleep. Split sleepers (6.78±2.13 hours) reported longer total sleep than morning (4.86±2.75 hours) or afternoon (5.11±2.37 hours) sleepers. Younger age (&amp;lt; 50y), single marital status, shorter night shift tenure (≤10 years), working ≤3 consecutive shifts, and having ill or disabled dependents were associated with greater prevalence of morning sleep; older age (≥50y), married or separated/widowed, &amp;gt;10 years night shift tenure, working ≥4 consecutive shifts, and having no dependents were associated with greater prevalence of afternoon or split sleep. Having childcare responsibility was associated with more split sleep than no children. Similarly, younger age (&amp;lt; 50y), singles, shorter night shift tenure, working three or fewer consecutive shifts, having ill or disabled dependents, and having a second job were associated with shorter total sleep. However, having childcare responsibility was associated with greater total sleep. Conclusion Sleep timing and duration between consecutive nights were influenced by age, marital status, dependents, night work tenure, and number of consecutive night shifts. Future studies are needed to explore what sleep pattern is most beneficial for sleep, performance, safety, and health outcomes of these workers. Support (if any) The study was supported by grant R01 AG044416 from the US National Institutes of Health.

0180 The Impact of Fatigue on Patient Care and Risk of Post-Shift Driving Collisions among 12-Hour Day and Night Shift Nurses

Abstract Introduction Evidence across industries links work-related fatigue with errors, accidents, and adverse long-term health outcomes. Within the healthcare profession, 12-hour day and night shifts have been widely adopted for nurses, despite concerns about fatigue from these shifts affecting nursing performance and safety. The purpose of this study was to determine the impact of 12-hour day-vs-night-shift-accumulated fatigue on patient care and driving safety. Methods This between-groups, repeated-measures quasi-experiment was conducted in the Washington State University (WSU) College of Nursing and Sleep and Performance Research Center. 44 nurses working 12-hour day shifts and 49 nurses working 12-hour night shifts were recruited from Providence Medical Center. Participants reported to WSU for testing on two separate occasions—once immediately following their 3rd consecutive 12-hour shift and once on their 3rd consecutive day (72 hours) off work. Nurses' sleep was monitored using wrist actigraphy, and were tested for patient care using LAERDAL medical simulation, and driving safety using an immersive driving simulator. Results We found that both day and night shift nurses were significantly more sleep restricted and subjectively sleepy following three consecutive shifts. Night shift nurses were significantly more impaired on patient care skills, in particular the communication domain, compared to day shift nurses (who were largely able to maintain performance across all tests). Furthermore, night shift participants had significantly greater lane deviation during the post shift drive home, a key indicator of collision risk, demonstrating impaired driving safety. Conclusion This study provides objective evidence of the impact of shift work-related fatigue on patient and nurse safety, allowing us to make concrete recommendations regarding safe shift-scheduling for day and nightshift nurses—information that may help keep nurses safer and improve patient care. Support (if any)

O066 The Impact of Work Break Characteristics on Sleep Duration in Heavy Vehicle Drivers

Abstract Introduction Heavy vehicle drivers (HVDs) frequently experience reduced sleep due to travelling long distances under non-standard work hours. Short sleep in HVDs can increase risk of motor vehicle crashes and falling asleep while driving. This study sought to examine the influence of break duration between shifts, break onset time, and prior shift duration on HVDs’ total sleep time (TST) between consecutive work shifts, and the interaction between break duration and break onset time. Methods Twenty-seven HVDs’ sleep and shift work were monitored for up to nine weeks through actigraphy, sleep diaries, and work diaries. Differences in TST between consecutive shifts and days off were assessed. Linear mixed models and pairwise comparisons evaluated the impact of break duration, break onset time, and prior shift duration on TST between shifts. Results TST was significantly lower between consecutive shifts (M=6.38-hours) compared to days off (M=7.63-hours), p&amp;lt;.001. Longer break durations were associated with more TST, p&amp;lt;.001. Break durations up to 7-, 9-, and 11-hours resulted in, on average, 4.76-, 5.66-, and 6.41-hours of sleep, respectively. Breaks starting between 00:01-08:00h led to shorter TST compared to breaks starting between 16:01-20:00h, p&amp;lt;.05. Prior shift duration and the interaction between break duration and break onset time were not associated with TST. Discussion HVDs’ TST between workdays are independently impacted by break duration and break onset time. Break durations between 7-11-hours, reflecting Australian and European break guidelines, result in insufficient sleep. Work regulations must evaluate appropriate break durations and break onset times to allow adequate sleep in HVDs.

New nurse scheduling model considering nurses’ seniority and the possibility of consecutive shifts under COVID-19 (A real case study)

ABSTRACT The nurse scheduling problem is the assignment of nurses to different working shifts while considering the existing constraints and rules. In recent years, medical centers have faced the challenge of resource planning due to the COVID-19 pandemic. In this study, a new mathematical model is formulated for nurse scheduling under the pandemic. In this model the nurses are categorized based on seniority and the auxiliary nurses are used because of the staff shortage. Apart from the hospital rules, conditions imposed during the COVID-19 pandemic are also considered. The proposed model is formulated in such a way that undesirable shifts are minimized, and also the violation of the schedule in the case of the possible absence of a nurse is prevented due to the model's robustness. The formulated model is applied in a real case in Iran, and the Genetic Algorithm (GA) is used as the solution method. To justify the Genetic Algorithm, different examples are generated and solved using this algorithm and the exact method. The results indicate that the Genetic Algorithm can provide near-optimal solutions with a mean optimality gap of 0.65% in a reasonable CPU time. The resulting timetable minimizes undesirable shifts and the utilization of auxiliary nurses.

The impact of break duration, time of break onset, and prior shift duration on the amount of sleep between shifts in heavy vehicle drivers.

This study aimed to examine the impact of break duration between consecutive shifts, time of break onset, and prior shift duration on total sleep time (TST) between shifts in heavy vehicle drivers (HVDs), and to assess the interaction between break duration and time of break onset. The sleep (actigraphy and sleep diaries) and work shifts (work diaries) of 27 HVDs were monitored during their usual work schedule for up to 9 weeks. Differences in TST between consecutive shifts and days off were assessed. Linear mixed models (followed by pairwise comparisons) assessed whether break duration, prior shift duration, time of break onset, and the interaction between break duration and break onset were related to TST between shifts. Investigators found TST between consecutive shifts (mean [SD] 6.38[1.38]h) was significantly less than on days off (mean [SD] 7.63[1.93]h; p < 0.001). Breaks starting between 12:01 and 8:00 a.m. led to shorter sleep (p < 0.05) compared to breaks starting between 4:01 and 8:00 p.m. Break durations up to 7, 9, and 11 h (Australian and European minimum break durations) resulted in a mean (SD) of 4.76(1.06), 5.66(0.77), and 6.41(1.06)h of sleep, respectively. The impact of shift duration prior to the break and the interaction between break duration and time of break were not significant. HVDs' sleep between workdays is influenced independently by break duration and time of break onset. This naturalistic study provides evidence that current break regulations prevent sufficient sleep duration in this industry. Work regulations should evaluate appropriate break durations and break onset times to allow longer sleep opportunities for HVDs.