Duty Periods Research Articles

Sleep and Alertness in North Sea Helicopter Operations

Dutch North Sea helicopter operations are characterized by multiple sector flights to offshore platforms under difficult environmental conditions. In the context of a Ministry of Transport program to improve safety levels of helicopter operations, we assessed effects of pre-duty sleep, pre-duty travel time, and workload factors on the alertness and vigilance of pilots. Data of 24 pilots comprising 224 duty days were analyzed. Pilots performed 10-min test sessions after wake up, pre-duty, halfway-duty, end-duty, and at bedtime during normal duty rosters. Test sessions included completion of a vigilance task, vigor and sleepiness ratings, and questions on sleep and operational characteristics. Pilots wore an actometer to objectify sleep data. Vigor scores were high and sleepiness levels were low during the entire flight duty periods (FDPs), while vigilance was impaired only 6.8% in the course of the FDPs. Pre-duty sleep before morning duties was 1.5 h shorter than sleep before duties starting after midday. Longer pre-duty travel time was correlated with shorter pre-duty sleep and lower vigilance levels during duty. During the FDPs, pilots maintained alertness and vigilance levels that may be considered safe in terms of alertness-related flight safety. This favorable outcome may be attributed to reasonable length of FDPs, favorable circadian start and end times of duties, sufficient opportunities for restorative pre-duty sleep, and relatively good weather conditions. Appropriate FDP scheduling is an important measure to optimize alertness of helicopter pilots who have to cope with adverse environmental conditions and limited landing and air traffic control facilities.

Prospective Evaluation of Residents On Call: Before and After Duty-Hour Reduction

On July 1, 2009, in Ontario the maximum period of continuous duty that residents were permitted to work was reduced from 28 to 24 hours. We evaluated the effect of regulation on residents in 3 eras: 2 before (2005 and early 2009) and 1 after (late 2009) the duty-hour reduction. On-call pediatric residents on pediatric medicine rotations prospectively recorded the numbers of patients (assigned and admitted) and the durations of direct patient care, documentation, staff supervision, and education attended. Sleep was measured with actigraphy. The 51 residents worked 180 duty periods, were assigned a median of 6 (interquartile range: 4 -12) daytime patients and 24 (interquartile range: 19-30) overnight patients. Residents reported spending means of 239 minutes providing direct patient care, 235 minutes documenting, and 243 minutes sleeping and receiving 73 minutes of staff supervision and 52 minutes of education. From early 2009 to after duty-hour reduction, residents provided 47 fewer (19.6%) minutes of direct patient care (P = .056) and received 44 fewer minutes (60.3%) of supervision (P = .0005) but spent similar times documenting, receiving education, and sleeping. In early 2009, residents provided 73 more minutes (30.5%) of direct patient care (P = .0016), spent 63 more minutes (26.8%) documenting, and slept 105 fewer minutes (43.0%) (P = .0062) than in 2005. After duty-hour reduction in 2009, we found reduced supervision and direct patient care. Comparison of the 2 periods before duty-hour reduction showed less sleep and longer patient contact in early 2009, which suggests that changes occurred without regulation.

Effect of 16-Hour Duty Periods on Patient Care and Resident Education

To measure the effect of duty periods no longer than 16 hours on patient care and resident education. As part of our Educational Innovations Project, we piloted a novel resident schedule for an inpatient service that eliminated shifts longer than 16 hours without increased staffing or decreased patient admissions on 2 gastroenterology services from August 29 to November 27, 2009. Patient care variables were obtained through medical record review. Resident well-being and educational variables were collected by weekly surveys, end of rotation evaluations, and an electronic card-swipe system. Patient care metrics, including 30-day mortality, 30-day readmission rate, and length of stay, were unchanged for the 196 patient care episodes in the 5-week intervention month compared with the 274 episodes in the 8 weeks of control months. However, residents felt less prepared to manage cross-cover of patients (P = .006). There was a nonsignificant trend toward decreased perception of quality of education and balance of personal and professional life during the intervention month. Residents reported working fewer weekly hours overall during the intervention (64.3 vs 68.9 hours; P = .40), but they had significantly more episodes with fewer than 10 hours off between shifts (24 vs 2 episodes; P = .004). Inpatient hospital services can be staffed with residents working shifts less than 16 hours without additional residents. However, cross-cover of care, quality of education, and time off between shifts may be adversely affected.

Effects of duty hours and time of day on surgery resident proficiency

Background Night floats have evolved in the era of limited resident work hours. This study was designed to define the effect of restricted nighttime duty hours on the psychomotor and cognitive skills of surgery residents. Methods To quantify the effect of fatigue on the skills of residents on day-shift and night-float rotations, residents were asked to complete visuohaptic simulations before and after 12-hour duty periods and to rate their fatigue level with questionnaires. Results Both groups showed significant decrements in proficiency measures after their shifts compared with baseline. The night-float group showed more significant declines ( P < .05) in all areas assessed than the day-shift group. The night-float group was significantly less proficient in cognitive tasks after their shifts compared with the day-shift group. Conclusions The deterioration of surgical proficiency is to a degree dependent on the time of day during which call occurs, not solely on the length of call.

Residents, Training Directors Get New Duty-Hour Rules

Residents, Training Directors Get New Duty-Hour Rules

Out‐of‐hours demand in primary care: frequency, mode of contact and reasons for encounter in Switzerland

To investigate the demand for traditional out-of-hours general practitioner (GP) emergency care in Switzerland including GPs' satisfaction and reasons for encounter (RFE). During a 2-month period (2009), a questionnaire-based, cross-sectional study was performed in GPs participating in the mandatory out-of-hours service in the city of Zurich, Switzerland. The number and mode of patient contacts were assessed to investigate the demand for GP care in traditional out-of-hours services. GPs and patient characteristics, including RFE according to the International Classification of Primary Care, were noted. Descriptive statistics and non-parametric tests were conducted. Out of the 295 out-of-hours episodes during the study period, 148 (50%) duty periods were documented by a total of 93 GPs (75% men) with a mean (SD) age of 48.0 (6.2) years. The median (interquartile range) number of out-of-hours contacts was 5 (3-8) and the demand for home visits was significantly more common compared with practice and telephone consultations. A total of 112 different RFEs were responsible for the 382 documented patient contacts with fever accounting for the most common complaint (13.9%). Although 80% of GPs agreed to be satisfied overall with their profession as primary care provider, 57.6% among them were dissatisfied with the current out-of-hours service. Inappropriate payment and interference with their daily work in practice were most frequently reported. Our findings indicate that there is still strong patient demand for out-of-hours care with special need for home visits, suggesting that new organizational models such as integrating GPs into emergency care may not be an appropriate approach for all patients. Therefore, the ongoing reorganization of the out-of-hours-service in many health care systems has to be evaluated carefully in order not to miss important patient needs.

Long-haul pilots use in-flight napping as a countermeasure to fatigue

The aim of this study was to examine the effects of fatigue on the amount of in-flight sleep obtained by airline pilots during long-haul duty periods. A total of 301 pilots collected sleep/wake and work/rest data for a period of at least 2 weeks each. Fatigue likelihood, i.e. low, moderate, high, or extreme, was estimated for each duty period based on a pilot’s sleep/wake behaviour prior to duty and the time of day that the duty period occurred. Participants obtained 1.8 h of sleep (i.e. 27% of their rest time) during duty periods with low fatigue likelihood and 3.7 h of sleep (i.e. 54% of their rest time) during duty periods with extreme fatigue likelihood. These results indicate that (i) long-haul pilots obtain substantially more sleep during duty periods when fatigue is likely to be extreme than when fatigue is likely to be low and (ii) long-haul pilots use in-flight napping as a fatigue countermeasure, but more could be done to increase its efficacy.

Use of strategies from high-reliability organisations to the patient hand-off by resident physicians: practical implications

Background:Limits on resident hours increase the frequency of patient hand-offs and may contribute to information transfer problems that contribute to adverse outcomes. This study analysed attributes that affect hand-off accuracy,...

Fatigue Countermeasures in Aviation

Pilot fatigue is a significant problem in modern aviation operations, largely because of the unpredictable work hours, long duty periods, circadian disruptions, and insufficient sleep that are commonplace in both civilian and military flight operations. The full impact of fatigue is often underappreciated, but many of its deleterious effects have long been known. Compared to people who are well-rested, people who are sleep deprived think and move more slowly, make more mistakes, and have memory difficulties. These negative effects may and do lead to aviation errors and accidents. In the 1930s, flight time limitations, suggested layover durations, and aircrew sleep recommendations were developed in an attempt to mitigate aircrew fatigue. Unfortunately, there have been few changes to aircrew scheduling provisions and flight time limitations since the time they were first introduced, despite evidence that updates are needed. Although the scientific understanding of fatigue, sleep, shift work, and circadian physiology has advanced significantly over the past several decades, current regulations and industry practices have in large part failed to adequately incorporate the new knowledge. Thus, the problem of pilot fatigue has steadily increased along with fatigue-related concerns over air safety. Accident statistics, reports from pilots themselves, and operational flight studies all show that fatigue is a growing concern within aviation operations. This position paper reviews the relevant scientific literature, summarizes applicable U.S. civilian and military flight regulations, evaluates various in-flight and pre-/postflight fatigue countermeasures, and describes emerging technologies for detecting and countering fatigue. Following the discussion of each major issue, position statements address ways to deal with fatigue in specific contexts with the goal of using current scientific knowledge to update policy and provide tools and techniques for improving air safety.

Hippocrates Affirmed? Limiting Residents' Work Hours Does No Harm to Patients

In this issue, the studies by Shetty and Bhattacharya and Horwitz and colleagues attempt to answer the following question: Did the resident work-hour rules violate the Hippocratic principle of doin...

Sleepiness and Sleep in a Simulated “Six Hours On/Six Hours Off” Sea Watch System

Ships are operated around the clock using rapidly rotating shift schedules called sea watch systems. Sea watch systems may cause fatigue, in the same way as other irregular working time arrangements. The present study investigated subjective sleepiness and sleep duration in connection with a 6 h on/6 h off duty system. The study was performed in a bridge simulator, very similar to those found on ships. Twelve officers divided into two groups participated in the study that lasted 66 h. Half of the subjects started with the 06:00–12:00 h watch and the other half with the 12:00–18:00 h watch. The subjects alternated between off‐duty and on‐duty for the remainder of the experimental period. Approximately halfway through the experiment, the 12:00–18:00 h watch was divided into two 3 h watches/off‐duty periods. The effect of this was to reverse the on‐duty/off‐duty pattern between the two groups. This enabled all subjects to work the four possible watches (00:00–06:00 h, 06:00–12:00 h, 12:00–18:00 h, and 18:00–24:00 h) in an order that was essentially counterbalanced between groups. Ratings of sleepiness (Karolinska Sleepiness Scale; KSS) were obtained every 30 min during on‐duty periods and if subjects were awake during off‐duty periods. The subjectively rated duration of sleep was recorded after each off‐duty period that preceded watch periods when KSS was rated. The results showed that the average level of sleepiness was significantly higher during the 00:00–06:00 h watch compared to the 12:00–18:00 h and 18:00–24:00 h watches, but not to the 06:00–12:00 h watch. Sleepiness also progressed significantly from the start toward the end of each watch, with the exception of the 06:00‐12:00 h watch, when levels remained approximately stable. There were no differences between groups (i.e., the order between watches). Sleep duration during the 06:00–12:00 h off‐duty period (3 h 29 min) was significantly longer than during the 12:00–18:00 h period (1 h 47 min) and the 18:00–24:00 h period (2 h 7 min). Sleep during the 00:00–06:00 h period (4 h 23 min) was longer than all sleep periods except the 06:00–12:00 h period. There were no differences between groups. In spite of sufficient opportunities for sleep, sleep was on the average around 1–1 h 30 min shorter than the 7–7 h 30 min that is considered “normal” during a 24 h period. This is probably a consequence of the difficulty to sleep during daytime due to the alerting effects of the circadian rhythm. Also, sleepiness during the night and early mornings reached high levels, which may be explained by a combination of working close to or during the circadian trough of alertness and the relatively short sleep periods obtained. An initial suppression of sleepiness was observed during all watches, except for the 06:00–12:00 h watch. This suppression may be explained by the “masking effect” exerted by the relative high levels of activity required when taking over the responsibility of the ship. Toward the end of watches, the levels of sleepiness progressively increased to relatively high levels, at least during the 00:00–06:00 h watch. Presumably, initially high levels of activity are replaced by routine and even boredom.

Symposium Resident Work-Hour Guidelines&lt;sbt aid="971631"&gt;A Sentence or An Opportunity for Orthopaedic Education?&lt;cross-ref type="fn" refid="fn1"&gt;*&lt;/cross-ref&gt;&lt;/sbt&gt;

Not since 1910, when Abraham Flexner established a set of standards and an accreditation process for schools of medicine in the United States1, has the foundation of American medical education been so shaken as it has by the 2001 Accreditation Council for Graduate Medical Education (ACGME) Outcome Project. Predicated on imperatives derived from a public call for regulation and accountability in support of patient safety and an evolving appreciation of the education process and the optimal learning environment, the ACGME instituted standards and limitations for the work hours of residents participating in accredited programs2. Amid protest largely from the sector of surgical specialists during the period of preparation and review, these restrictions were approved in February 2003 and became effective on July 1, 2003. Averaged over four weeks, resident duty hours are now limited to eighty hours per week, in-house call frequency cannot exceed once every third night, and one twenty-four-hour day in seven must be free of patientcare responsibilities. There is a twenty-four-hour continuous duty limit with a supplemental six-hour transition period to accommodate patient transfer and debriefing logistics as well as didactic activity. A minimum of ten hours must be allowed between scheduled duty periods. Included in the eighty-hour weekly tally are hours spent in-house while on home call as well as moonlighting hours, provided that such activity is approved by the program director. Anticipating resistance to change in the implementation of these guidelines, the Outcome Project also mandated an educational program for faculty and residents on the effects of fatigue, support to reduce time on routine tasks, and a rigorous enforcement program that held program directors, rather than the residents themselves, accountable for performing within the work-hour restrictions. While a 10% increase in duty hours has been offered on a case-by-case basis for …

Sleep Loss and Performance in Residents and Nonphysicians: A Meta-Analytic Examination

To explore the effect of sleep loss on cognitive function, memory, and vigilance in resident physicians and nonphysicians and on residents' clinical performance. Meta-analysis of 60 studies on the effect of sleep deprivation, with a total sample of 959 physicians and 1,028 nonphysicians and 5,295 individual effect indexes. Cognitive performance and performance on clinical tasks under acute and partial chronic sleep deprivation. Additional analyses stratified the data by physician/nonphysician, type of performance, and length and type of sleep loss and assessed the combined effect of several of these factors. Sleep loss of less than 30 hours reduced physicians' overall performance by nearly 1 standard deviation and clinical performance by more than 1.5 standard deviations. The effect of sleep deprivation was larger in nonphysicians than in physicians (corrected d value -.995 vs -.880), with these smaller effects likely resulting from "study factors," primarily variation in the hours without sleep prior and chronically reduced sleep in the "rested" controls in physician studies. The weekly hours and continuous wakefulness permitted under the current national minimum standards for residents may not completely guard against the negative effect of sleep loss on cognitive and clinical performance. Research is needed to explore the effect of continuous duty periods and chronic partial sleep loss in residents and to assess the clinical and educational consequences of sleep loss. The goal should be to combine scientifically based duty-hour limits with broader efforts to enhance patient safety and resident learning.

Professionalism and the Shift Mentality

The Halstedian tradition imbued the art of surgery with a deeply rooted sense of re-sponsibility and a powerful work ethic. As apprentice surgeons, junior residents gained reputations for professionalism when they immersed themselves in patient care so deeply and for such long periods that they owned their patients. No detail of patient care was so trivial that it could escape the effective intern. The introduction of strict limits on resident work hours brought many positive changes to training programs nationwide. An unintended consequence of this policy is the potential for the loss of patient ownership by trainees. Patient ownership is the philosophy that one knows everything about one's patients and does everything for them. It is a central tenet of surgical professionalism dating back decades and is fundamental when facing critical patient care decisions. The shortened duty periods and subsequent frequent transfer of responsibility to others pose a challenge to the trainee's sense of professionalism and the continuity of patient care. This challenge must be addressed head-on. Residents must learn a New Professionalism that stems from sharing responsibility for the care of their patients. They must be given a new understanding of their responsibilities, new methods for organizing and sharing patient information, and new skills for directing team-based care as they work toward competency in systems-based practice. Residents, particularly junior residents, may lack many of these skills. The craft of conveying pertinent patient data to permit team-based care must be learned, just as all other forms of clinical communication are learned. And the unwillingness to relinquish patient ownership-the deep-seated desire to say, Nothing to do, I'll grab a nap and be back in a couple of hours-must be unlearned.

Fatigue in aviation

Pilot fatigue is a significant, but often under-reported problem in both civilian and military aviation operations. Although estimates vary, official statistics indicate that fatigue is involved in at least 4-8% of aviation mishaps, and surveys of pilots and aircrew members reveal that fatigue is an important concern throughout today's 24/7 flight operations. Regulatory efforts aimed at limiting flight hours and ensuring at least minimal periods of crew rest have to some extent mitigated fatigue-related difficulties in the cockpit, but it is clear that much remains to be done about this insidious threat to air safety. Scheduling factors, sleep deprivation, circadian disruptions, and extended duty periods continue to challenge the alertness and performance levels of both short-haul and long-haul pilots and crews. Solutions for these problems are not straightforward, but they can be developed through the cooperative efforts of scientists, regulators, managers, and the pilots themselves. Over the past 20 years, scientific understanding of human sleep, fatigue, and circadian rhythms has expanded considerably. The thorough integration of this new knowledge into modern crew-resource management practices will facilitate the establishment of optimal crew scheduling routines and the implementation of valid aviation fatigue countermeasures.

Are pilots at risk of accidents due to fatigue?

Problem: There is concern in the aviation community that pilot schedules can lead to fatigue and increased chance of an aviation accident. Yet despite this concern, there is little empirical analysis showing the relationship between pilot schedules and commercial aviation accidents. This study attempts to demonstrate an empirical relationship between pilot schedules and aviation accidents. Method: Data for human factors-related accidents and pilot work patterns were identified. The distribution of pilot work schedule parameters for the accidents was compared to that for all pilots using a chi-square test to determine if the proportions of accidents and length of duty exposure were the same. If the distributions are the same, then one could infer that pilot human factor accidents are not affected by work schedule parameters. Results: The proportion of accidents associated with pilots having longer duty periods is higher than the proportion of longer duty periods for all pilots. Discussion: There is a discernible pattern of increased probability of an accident as duty time increases for commercial aircraft pilots in the United States. Impact on Industry: The analysis suggests that establishing limits on duty time for commercial pilots would reduce risk. Such a rule is likely to be expensive and could substantially impact the commercial airlines. In return, there is likely to be a reduction in the risk of commercial aviation accidents due to pilot fatigue.

Optimized Crew Scheduling at Air New Zealand

The aircrew-scheduling problem consists of two important subproblems: the tours-of-duty planning problem to generate minimum-cost tours of duty (sequences of duty periods and rest periods) to cover all scheduled flights, and the rostering problem to assign tours of duty to individual crew members. Between 1986 and 1999, Air New Zealand staff and consultants in collaboration with the University of Auckland have developed eight application-specific optimization-based computer systems to solve all aspects of the tours-of-duty planning and rostering processes for Air New Zealand's national and international operations. These systems have saved NZ$15,655,000 per year while providing crew rosters that better respect crew members' preferences.

Circadian Rhythm of Heart Rate, Urinary Cortisol Excretion, and Sleep in Civil Air Traffic Controllers

The examination of Air Traffic Controllers (ATCs) from the Warsaw Airport (Poland) included 24-hr ECG monitoring. The participants were 10 civil ATCs, 9 males and 1 woman. The study was carried out on a group of 19 ATCs during their duty periods, 14 of them working 12-hr shifts and 5 performing 24-hr duties. The participants collected urine every 4 hrs, and Cortisol concentration was determined. Further, the survey included the quality and duration of sleep, and subjective fatigue in the 62 participants.In ATCs, shift work modifies natural rhythms of the circulatory system and decreases the ability for intensified mental work at night. In consequence ATCs experience frequent sleep disorders.

Liquid nitrogen auto fill for temperature controlled cryogenic traps

We describe the principle of operation and construction of an inexpensive, reliable system for the automated dispensing of liquid nitrogen from a single supply Dewar to multiple cryogenic traps. The system can be run under full computer control and in conjunction with existing designs of traps will allow unattended operation over long duty periods combined with programmed temperature cycles.

Age and anesthetic practice: a regional perspective

Study Objective: To obtain information about practitioners’ behaviors, perceptions, and perspectives concerning issues related to advancing age and anesthetic practice.Design: Questionnaire survey mailed to 1,208 active and retired American Society of Anesthesiologists (ASA) members in Northern New England. Topics included hours worked, practice policies, stress level of activities, observed in colleagues and personally perceived errors and problems associated with performance, and plans, preparation, and reasons for retirement.Setting: Practicing respondents worked in academic, community, or federal hospitals, and in ambulatory surgical facilities.Measurements and Main Results: For descriptive analysis, counts and frequency distributions were calculated for each question. Statistical methods were used to test differences across age groups and to identify sources of differences. Approximately 40% of respondents in each age group worked an average work week of 50 to 59 hours. Respondents aged 40 to 49 years worked the longest work weeks and duty periods and were more concerned about liability issues than other age groups. Respondents age 60+ tended to work shorter average and maximum work weeks, although 5% of them continued to work 70- to 79-hour weeks. There was no statistically significant difference in hours worked among men and women. Approximately 20% to 30% of respondents relieved older colleagues of late night or call duties, and asked them to restrict or to stop practice out of concern for patient safety. Night call was equally stressful for all age groups. Economic uncertainty, production pressure, and interpersonal relations were more stressful for younger respondents. In preparation for retirement, shifting away from complex cases and phased reduction in clinical activity were increasingly prevalent with each advancing age group. Important reasons for retirement included attitude changes, physical limitations, and declining health.Conclusions: Despite modest age-associated trends, chronological age per se is not a strong correlate of an individual’s practice pattern, behaviors, or perceptions about performance.