Young hospital doctors after night duty: their task-specific cognitive status and emotional condition

Impact of duty hours restrictions on quality of care and clinical outcomes

BACKGROUND

In July 2003, the Accreditation Council for Graduate Medical Education instituted residency duty-hours requirements in response to growing concerns regarding clinician fatigue and the incidence of medical errors. These changes, which limited maximum continuous hours worked and total hours per week, often resulted in increased discontinuity of care. The objective of this study was to assess the impact of the duty-hours restrictions on quality of care and outcomes of patients with acute coronary syndrome.

METHODS

We performed a retrospective analysis of 1003 consecutive patients with acute coronary syndrome admitted to the University of Michigan Hospital between July 2002 and June 2004. Patients were stratified by hospital admission during academic year 2002-2003 (pre-duty-hours changes, n=572) and academic year 2003-2004 (post-duty-hours changes, n=431). Main outcome measures included differences in adherence to quality indicators, length of stay, and in-hospital and 6-month adverse events.

RESULTS

Post-duty-hours changes, there was an increase in the usage of beta-blockers (85.8% vs 93.8%, P <.001), angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (65.7% vs 71.8%, P=.046), and statins (76.2% vs 84.0%, P=.002) at time of discharge. Length of stay decreased from 3.1 days to 2.8 days, P=.002. There was no difference in in-hospital mortality (4.2% vs 2.8%, P=.23). Six-month mortality (8.0% vs 3.8%, P=.007) and risk-adjusted 6-month mortality (odds ratio 0.53, 95% confidence interval, 0.28-0.99, P=.05) decreased after the duty-hours changes.

CONCLUSIONS

Implementation of the Accreditation Council for Graduate Medical Education residency duty-hours restrictions on an academic inpatient cardiology service was associated with improved quality of care and efficiency in patients admitted with acute coronary syndrome. In addition, improved efficiency did not adversely impact patient outcomes, including mortality.

Sleep facilitates consolidation of emotional declarative memory

Both sleep and emotion are known to modulate processes of memory consolidation, yet their interaction is poorly understood. We examined the influence of sleep on consolidation of emotionally arousing and neutral declarative memory. Subjects completed an initial study session involving arousing and neutral pictures, either in the evening or in the morning. Twelve hours later, after sleeping or staying awake, subjects performed a recognition test requiring them to discriminate between these original pictures and novel pictures by responding "remember,""know" (familiar), or "new." Selective sleep effects were observed for consolidation of emotional memory: Recognition accuracy for know judgments of arousing stimuli improved by 42% after sleep relative to wake, and recognition bias for remember judgments of these stimuli increased by 58% after sleep relative to wake (resulting in more conservative responding). These findings hold important implications for understanding of human memory processing, suggesting that the facilitation of memory for emotionally salient information may preferentially develop during sleep.

Circadian rhythms in cognitive performance: Methodological constraints, protocols, theoretical underpinnings

The investigation of time-of-day effects on cognitive performance began in the early days of psychophysiological performance assessments. Since then, standardised, highly controlled protocols (constant routine and forced desynchrony) and a standard performance task (psychomotor vigilance task) have been developed to quantify sleep-wake homeostatic and internal circadian time-dependent effects on human cognitive performance. However, performance assessment in this field depends on a plethora of factors. The roles of task difficulty, task duration and complexity, the performance measure per se, practice effects, inter-individual differences, and ageing are all relevant aspects. Therefore, well-defined theoretical approaches and standard procedures are needed for tasks pinpointing higher cortical functions along with more information about time-dependent changes in the neural basis of task performance. This promises a fascinating challenge for future research on sleep-wake related and circadian aspects of different cognitive domains.

Sleep debt and outside employment patterns in helicopter air medical staff working 24-hour shifts

INTRODUCTION

Twenty-four hour availability creates physiological and psychological challenges for air medical teams. The 24-hour shift (24H) is a common staffing pattern in the air medical community. We report sleep dept and pre-duty activity patterns for 24H medical staff members at helicopter air medical transport programs.

METHODS

An anonymous survey collecting self-reported sleep quantities for off-duty, immediate pre-duty, and on-duty periods, along with self-reported outside employment patterns, was distributed to medical team members at cluster sample of 10 rotor wing air medical programs selected by stratified random sample to ensure geographic and operational diversity. Both matched-sample comparisons of sleep quantities in different phases of the duty-cycle and independent-sample comparisons between staff with and without outside employment had 80% power to detect a difference in means of 60 minutes at a 0.05 two-sided significance level using the appropriate t-test. Descriptive statistics are also reported; means are reported with the standard deviation.

RESULTS

A total of 138 surveys were returned (69.0%) and the 133 (66.5%) that were fully completed were utilized for analysis. 24H crewmembers average nearly the same amount of sleep in 24 hour periods on both duty and non-duty days (6.9 +/- 1.3 v. 6.4 +/- 1.8 hours, p = NS, range 3 - 10 for duty days and 4 - 10 for non-duty days). On duty, they average 1.1 +/- 1.3 hours of sleep in the first half of their shifts (range 0 to 5) and 5.3 +/- 1.4 hours in the overnight portion (range 2 - 9). The lowest amount of on-duty sleep reported in the past 30 days ranged from 0 to 6 hours, averaging 1.9 +/- 1.7 hours. The minimum pre-duty sleep reported by 24H crewmembers prior to any shift in the past month averaged 4.6 +/- 1.6 hours (range 0-8), with 3.8% having reported in the past month with no sleep before their 24-hour shift. Outside employment (OE) in addition to the flight position was common for 24H crewmembers (81.1% of respondents). Pre-duty sleep did not differ significantly between 24H crewmembers with and without OE, but 16.3% of surveyed 24H crewmembers with OE had reported for flight duty within eight hours of leaving OE within the past 30 days.

CONCLUSION

In the programs surveyed, 24H crewmembers completed an average duty cycle with little sleep debt and were unlikely to be sleepless prior to reporting for a shift. OE is common for 24H medical staff and some personnel report for flight duty within eight hours of leaving an OE position. As the industry considers the impact of fatigue on operational safety, shift length, on-duty rest, and outside employment will be important considerations.

The 80-hour duty week: rationale, early attitudes, and future questions

There is considerable concern and much evidence resident fatigue results in medical errors, some of which have serious consequences. Similarly, fatigue causes poor health in house-staff and places these individuals at greater risk for personal injuries, including motor vehicle accidents. These circumstances led the Accreditation Council on Graduate Medical Education to develop and, on July 1, 2003, to implement guidelines for all residency training programs limiting the time of in-house duty to 80 hours per week. Surveys of orthopaedic residents by the American Academy of Orthopaedic Surgeons, before and right after implementation of these new duty rules, confirm housestaff were working longer than 80 hours before July 2003 and are largely in compliance since that date. Residents generally approve of these changes and are personally happier, but also express concern for a loss of continuity of care and reduced exposure to operative cases. It remains to be demonstrated whether these new rules will improve patient care, enhance housestaff well-being, or influence education.

24 Hours On-Call and Acute Fatigue No Longer Worsen Resident Mood Under the 80-Hour Work Week Regulations

PURPOSE

Studies in on-call residents have shown that mood is worsened by fatigue as indicated by increased scores on measures of depression, anxiety, confusion, and anger using the Profile of Mood States (POMS). In prior sleep deprivation studies, mood has been shown to be more affected than either cognitive or motor performances. The purpose of this study was to examine the effect of the 80-hour work week regulations on resident mood in general and in a post-call period (PC).

METHODS

Institutional Review Board approval was obtained to survey the residents and publish the results. POMS is a 65-item adjective questionnaire that includes subscales for measuring tension-anxiety, anger-hostility, depression-dejection, vigor-activity, fatigue-inertia, and confusion-bewilderment, with the summation of the scales forming a total mood disturbance score. Surgical residents were tested at a 9 am didactic curriculum session (9 am has been shown to correlate with the nadir of performance). Residents were tested after nights off call (NOC) or after PC. Time asleep in the preceding 24 hours and other demographic data were also collected. Acute fatigue (AF) was defined as <4 hours sleep. The two-sample t-test and linear regression were used to assess differences between groups.

RESULTS

A total of 123 standardized POMS mood questionnaires were administered on 4 occasions to 51 surgical residents, 35 men and 16 women at levels PGY-1 through PGY-5. Overall, 33 tests (27%) were taken after PC and 90 (73%) were taken after NOC. Acute fatigue residents had a mean sleep time of 2.2 (+/-1.5) hours, whereas rested (R) residents had a mean sleep time of 6.7 (+/-2.2) hours (whether PC or NOC). No statistical differences in mean values of vigor, anger, depression, concentration, fatigue, tension, or total score were observed between PC and NOC or between AF and R residents. There was no significant relationship between acute sleep deprivation and total mood disturbance, whether PC or NOC. In linear relationships, NOC total score and hours slept had r2 = 0.01 (p = 0.44), whereas PC total score and hours slept had r2 = 0.07 (p = 0.14).

CONCLUSION

Although POMS was given 4 times, only 27% were PC, which reflects our 1 in 4 night in-house coverage. In contrast to earlier studies, resident mood, as measured by POMS, is no longer related to PC/NOC or acute fatigue. Previous studies have shown that loss of sleep was associated with declining mood. The lack of such a relationship in this study may be related to the new regulations. It has been assumed that people can adapt to chronic sleep loss but have a harder time coping with the effects of acute sleep deprivation. If, however, the new regulations have relieved chronic sleep deprivation, then a well-rested resident can periodically cope with the effects of acute sleep deprivation. Perhaps by eliminating chronic sleep debt, work hour restrictions seem to have removed the negative impact of PC seen in the prior era. Further studies should increase the number of residents studied, have numerous repeat NOC and PC pairs in same subjects, compare different services with different workloads, junior and senior residents, and in-house and at-home call schedules.

Impaired decision making following 49 h of sleep deprivation

Sleep deprivation reduces regional cerebral metabolism within the prefrontal cortex, the brain region most responsible for higher-order cognitive processes, including judgment and decision making. Accordingly, we hypothesized that two nights of sleep loss would impair decision making quality and lead to increased risk-taking behavior on the Iowa Gambling Task (IGT), which mimics real-world decision making under conditions of uncertainty. Thirty-four healthy participants completed the IGT at rested baseline and again following 49.5 h of sleep deprivation. At baseline, volunteers performed in a manner similar to that seen in most samples of healthy normal individuals, rapidly learning to avoid high-risk decks and selecting more frequently from advantageous low-risk decks as the game progressed. After sleep loss, however, volunteers showed a strikingly different pattern of performance. Relative to rested baseline, sleep-deprived individuals tended to choose more frequently from risky decks as the game progressed, a pattern similar to, though less severe than, previously published reports of patients with lesions to the ventromedial prefrontal cortex. Although risky decision making was not related to participant age when tested at rested baseline, age was negatively correlated with advantageous decision making on the IGT, when tested following sleep deprivation (i.e. older subjects made more risky choices). These findings suggest that cognitive functions known to be mediated by the ventromedial prefrontal cortex, including decision making under conditions of uncertainty, may be particularly vulnerable to sleep loss and that this vulnerability may become more pronounced with increased age.

Brief report: Housestaff adherence to cervical cancer screening recommendations

BACKGROUND

Postgraduate training involves intensive clinical education characterized by long work hours with minimal flexibility. Time demands may be a barrier to obtaining preventive care for housestaff during postgraduate training.

OBJECTIVE

Assess adherence to United States Preventive Services Task Force (USPSTF) cervical cancer screening recommendations.

DESIGN

Cross-sectional survey.

PARTICIPANTS

Convenience sample of female housestaff at 1 university hospital.

MEASUREMENTS

Primary outcomes included (1) adherence to USPSTF recommendations, (2) perception of adherence to recommendations, and (3) barriers to obtaining preventive care.

RESULTS

Surveys were completed by 204 housestaff. Overall, 81% of housestaff were adherent to USPSTF screening recommendations. Housestaff requiring screening in the past year were less likely to be adherent when compared with housestaff requiring screening in the past 3 years. Overall, 84% accurately perceived their screening behavior as adherent or nonadherent (kappa=0.58). Of the 43% who identified a barrier to obtaining preventive care, not having time to schedule or keep appointments was reported most frequently (n=72).

CONCLUSIONS

Housestaff accurately perceived their need for cervical cancer screening and were generally adherent to USPSTF recommendations, even though lack of time during postgraduate training was frequently reported as a barrier to obtaining preventive care. However, we found lower adherence among a small subgroup of housestaff at a slightly greater risk for cervical disease and most likely to benefit from screening.

Effects of sleep deprivation on Color-Word, Emotional, and Specific Stroop interference and on self-reported anxiety

The aim of this study was principally to assess the impact of sleep deprivation on interference performance in short Stroop tasks (Color-Word, Emotional, and Specific) and on subjective anxiety. Subjective sleepiness and performance on a psychomotor sustained attention task were also investigated to validate our protocol of sleep deprivation. Twelve healthy young subjects were tested at four-hourly intervals through a 36-h period of wakefulness under a constant routine protocol. Analyses of variance for repeated measurements revealed that self-assessment of sleepiness on a visual analogue scale as well as mean reaction time performance on the sustained attention task, both for the first minute and for 10 min of testing, were worsened by sleep deprivation. Analyses revealed an increase in self-reported anxiety scores on the STAI questionnaire but did not reveal any significant effect after sleep deprivation either on indexes of interference or on accuracy in Stroop tasks. However, analyses showed sensitivity to circadian effect on verbal reaction times in the threat-related (Emotional) and sleep-related (Specific) Stroop tasks. We concluded that 36 h of prolonged wakefulness affect self-reported anxiety and Emotional Stroop task resulting in a cognitive slowing. Moreover, total sleep deprivation does not affect interference control in any of the three short Stroop tasks.

Sleep deprivation does not affect operative results in cardiac surgery

BACKGROUND

There has been an increasing trend towards the mandatory reduction in work hours for physicians because of the fear that sleep-deprived (SD) surgeons are more prone to make mistakes. We hypothesized that sleep deprivation would not be associated with increased morbidity or mortality in cardiac operations.

METHODS

A retrospective review was done of all cases performed by all attending cardiac surgeons from January 1994 to April 2003. Complication rates of cases performed by SD surgeons were compared with cases done when the surgeons were not sleep-deprived (NSD). A surgeon was deemed sleep deprived if he or she performed a case the previous evening that started between 10:00 pm and 5:00 am, or ended between the hours of 11:00 pm and 7:30 am.

RESULTS

A total of 6,751 cases were recorded in the Society of Thoracic Surgeons database over the 9-year period examined. Of these, 339 cases (5%) were performed by SD surgeons, and 6,412 (95%) cases were performed by NSD surgeons. Mortality rates for coronary artery bypass operations showed no significant differences (1.7% [SD = 4/223] vs 3.1% [NSD = 133/4206)] p = 0.34). Operative (p = 0.47), pulmonary (p = 0.60), renal (p = 0.93), neurologic (p = 0.11), and infectious (p = 0.87) complications of all cases also failed to show any statistically significant differences in any group. Perfusion times, cross-clamp times, and the use of blood products were also similar between groups.

CONCLUSIONS

Sleep deprivation does not affect operative morbidity or mortality in cardiac surgical operations. These data do not support a need for work hour restrictions on surgeons.

Effects of working permanent night shifts and two shifts on cognitive and psychomotor performance

OBJECTIVES

The study aimed to clarify whether cognitive and psychomotor performance, which are important for occupational and traffic safety, are impaired by working permanent night shifts (NSs) compared with early-late two shifts (TSs) and whether age and chronobiological type influences the relationship between shift and performance.

METHODS

The study included 44 male automobile workers, 20 working TSs and 24 working NSs. Chronobiological type was determined by questionnaire (D-MEQ). Each subject was tested at the beginning and end of the shift for alertness [by a visual analogue scale (VAS)]; feeling of well-being (Basler); concentration and accuracy (d2); reaction speed, orientation and reaction to stress (Vienna System).

RESULTS

TS workers were more frequently morning types whereas the NS workers were more frequently evening types. In the performance tests, the TS and NS workers did not differ at shift start or shift end. Over the course of the shift, concentration and accuracy improved in both groups, as did reaction to stress. Chronobiological type alone or in combination with shift type had no effect on performance.

CONCLUSIONS

The results of this study indicate that-if chosen voluntarily-working NSs has no immediate negative effects on cognitive and psychomotor performance when compared with working TSs. There was no indication of an increased risk of accidents after working NSs. The unequal distribution of the circadian types in the shift groups may indicate selection.

Balancing continuity of care with residents' limited work hours: defining the implications

The impact of the new resident work-hours rules on all aspects of patient care and education must be considered. While physician fatigue has taken center stage as the primary motivation behind this movement, the effect of these rules on the continuity of care for hospitalized patients needs to be critically analyzed from the perspectives of patients, physicians, and the health care system. The authors describe a conceptual framework that places continuity at the center and then considers the benefits and drawbacks of preserving continuity from the perspectives of the major stakeholders. They describe the categories of outcomes related to residents' fatigue and sleep deprivation that have been studied. Only a few studies have addressed patient outcomes, while most address resident outcomes. The authors discuss some of the possible solutions, including night float and the British system of shift work, and suggest that these solutions have different effects on each group of stakeholders, including both intended and unintended benefits and harms. Finally, the research agenda that arises from this framework is described. It includes taking into account multiple perspectives, identifying important outcomes, and considering unintended consequences. Using this framework, medical educators may better evaluate previous studies and consider remaining questions.

Safety in training and learning in the intensive care unit

Resident and subspecialty fellow trainees in the intensive care unit (ICU) present risks for patient safety because of their inexperience yet offer opportunities to promote safe patient care because of their around-the-clock presence and their involvement in frontline processes of care. Most trainees approach their ICU experiences without previous education in performance improvement or patient safety. This article reviews the barriers that are faced by residents in providing safe patient care and outlines the nature of a patient safety curriculum that could tap the opportunities that are presented by trainees to promote safer patient care.

Resident duty hours in American neurosurgery

The unexpected death of Libby Zion, at New York Hospital in 1984, led to a series of investigations that recently resulted in profound changes in resident duty hours. On July 1, 2003, the Accreditation Council for Graduate Medical Education (the governing body of all residency programs in the United States) mandated the following work hours rules: no more than 80 hours per week, no more than 24 hours of continuous patient care (with an added 6-hour transition period), 1 day in 7 free of patient care responsibilities, and a minimum of 10 rest hours between duty periods. These rules are based on a considerable body of scientific study indicating that sleep loss affects cognitive performance and, possibly, patient care. The new work hours have stimulated vigorous debate, both pro and con. Those arguments are reviewed.

Sleep deprivation and junior doctors' performance and confidence

PURPOSE OF STUDY

To determine whether sleep deprivation affects not only junior doctors' performance in answering medical questions but whether their ability to judge their own performance is also affected by lack of sleep.

METHODS

A questionnaire based follow up study in two district general hospitals of the Carmarthenshire NHS Trust. Eleven house officers and 15 senior house officers (SHOs) within the medical directorate participating in the on-call rota were recruited between July 1999 and May 2000.

RESULTS

SHOs answered significantly more questions correctly (p=0.04) and were more confident than house officers when they were either correct or incorrect (p<0.001). Length of unbroken or continuous sleep is associated with more correct answers (p=0.03) and higher energy (p=0.09) and confidence (p=0.07) scores self rated by the profile of mood states. Length of continuous sleep was not related to the appropriateness of confidence, as measured by the "within-subject confidence-accuracy correlation" (p=0.919).

CONCLUSIONS

SHOs performed better than house officers even allowing for sleep loss. Sleep deprivation had adverse effects on mood and performance but junior doctors can still monitor their performance and retain insight into their own ability when sleep deprived.

Sleep loss and fatigue in medical training

The effects of sleep loss and fatigue in the context of medical training is a topic that has generated considerable interest, as well as controversy, over the past two decades. The sleep deprived state in medical trainees potentially impacts on a variety of domains relevant to medical care, including performance on neurobehavioral and work-related tasks, mood and affect, learning, risk for and commission of medical errors, and the health and well-being of medical students and residents. The following review provides a summary of research conducted on this topic in the past decade, including the relation of sleep loss and fatigue to medical errors and the quality of patient care. Those few studies that have analyzed the use of operational alertness management strategies, countermeasures, and educational interventions to address and mitigate the effects of sleep loss and fatigue are also reviewed. There is clearly a need for additional research to further explore the complex interaction between sleep and fatigue and medical care, and to support the development and implementation of regulatory policies based on sound science.

Alterations of host defence system after sleep deprivation are followed by impaired mood and psychosocial functioning

In healthy humans, sleep deprivation (SD) has consistently been demonstrated to impair different parameters of the host defence system and of psychosocial functioning. However, the individual timing of these alterations and their possible association have remained unknown so far. We therefore investigated functional measures of the individual host defence system as well as of subjective well-being and psychosocial performance in 10 healthy male adults before and after SD, as well as after recovery sleep. In detail, we examined the number of leukocytes, granulocytes, monocytes, lymphocytes, B cells, T cells, T helper and cytotoxic T cells, natural killer (NK) cells as well as the interleukin-1 beta (IL-1 beta) release from platelets after serotonin (5-HT) stimulation. Mood and psychosocial performance (excitement, energy, ability to work and timidity) were measured by visual analogue scales. Taken together, SD induced a deterioration of both mood and ability to work, which was most prominent in the evening after SD, while the maximal alterations of the host defence system could be found twelve hours earlier, i.e., already in the morning following SD. Our findings therefore suggest an SD-induced alteration of these psychoimmune response patterns in healthy humans preceding deterioration of mood and psychosocial functioning.

Efficacy of 24-hour shifts: prepared or impaired? A prospective study

BACKGROUND

The effect of duty duration on performances is unknown. In a prospective cohort study model using repeated measures, we evaluated the effect of shift length on a battery of neuropsychologic performance indicators using our flight program as the test site.

METHODS

Flight nurses completing 24- and 12-hour shifts were tested on memory, attention, reasoning, motor, and speed measures. Ratings of stress, fatigue, sleep quality, and logged amount of work and sleep were evaluated from personal journals kept for this purpose. Data were analyzed by linear regression and repeated measures multivariate analysis of variance (MANOVA) and analysis of variance (ANOVA). Clinical significance was set at P < 0.05.

RESULTS

Fifteen subjects completed the testing and evaluation process. Neuropsychologic testing demonstrated that performance was not predicted by shift length, time of shift (day versus night), amount or quality of sleep before or during shift, or fatigue ratings. Age, gender, and education did not mediate shift length/test performance relationships. Uninterrupted sleep, stress ratings, and number of flights per shift modestly reduced some test scores. Predictably, repeated testings resulted in practice effects that reduced analysis power. We found that 24-hour shifts per se do not result in a cognitive decline compared with 12-hour shifts. Inconsistent sleep, number of flights, and the stressfulness of flights may have greater impact.

Young doctors' health--I. How do working conditions affect attitudes, health and performance?

Long hours and other difficult working conditions are thought to affect the health of young doctors, but there has been little evidence to support these assertions. Data are presented from a class cohort of junior doctors in the U.K. showing the relationships between working conditions, health and performance. Long hours appear to have short-term consequences in terms of the doctors feeling unwell and reporting poor performance, as measured by the somatic and social dysfunction scales of the General Health Questionnaire, but there are no demonstrated long-term health consequences. Instead, a number of working conditions, number of emergency admissions, number of deaths on the ward and the number of minor menial tasks contribute to a perception of being overwhelmed, as revealed by factor analysis of the Attitudes to Work questionnaire. This factor correlates significantly with a range of long-term physical and mental health measures as well as measure of work performance.