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Shift Work and the Efficient ED

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1 Shift Work and the Efficient ED
Vicken Y. Totten MD: Emergency Physician and Career-long Shift Worker


3 Goals and Objectives: Offer concrete suggestions to optimize your ED workforce by... Discussing the effects of poorly conceived shift work on work performance by: Describe normal sleep structure Definitions and shift patterns

4 SLEEP Sleep, that knits the ravell'd sleave of care,
The death of each day's life, sore labour's bath, Balm of hurt minds, great nature's second course, Chief nourisher in life's feast. - Shakespeare, Macbeth, Act II, Scene I


6 Definitions Chronodisruption -- the circadian rhythms are out of synchronization with each other and with the external world. Classic example is jet lag. Sleep deprivation -- lack of core sleep Sleepiness -- the feeling of wishing to sleep; drowsiness

7 Normal Human Circadian Cycle
Day = alert; night = sleep. Most physiologic systems cycle through the 24 hour “day” Modern life is increasingly 24/7, especially Emergency Medicine Medicine is far behind industry in recognizing the inefficiencies of shift work

8 Circadian rhythms All body systems change rhythmically
Most humans have about hour circadian cycle Other well known cycles have different periods: 90 minute alertness cycle, fertility monthly cycle, etc. Not all systems adapt to a new schedule at same rate!

9 Concept of “Core Sleep”
Horne: first three SWS cycles with their REM periods "optional" sleep the rest of the night: more REM, less SWS Core sleep: about 5 hours for most persons Only core sleep made up.

10 Concept of Sleepiness 2 components: core versus optional
missing core sleep (physiologic) -- disrupts physiologic systems missing optional sleep (psychological) -- mostly psychological / mood effects both feel drowsy

11 Sleep deprivation loss of "optional sleep" (sleeping less than one's habit) causes drowsiness, no other serious effects "core sleep" deprivation (less than 5 hours of slow wave sleep) -- true sleep deprivation Sleep deprivation causes both physiologic and psychological ill effects

12 Emergency Medicine vs. Office-based Specialties
On call -- potential for disrupted sleep or sleep deprivation. Does not affect zeitgibers or circadian rhythm On duty -- In the work environment, performing diurnal tasks during a “day” defined by a clock rather than by social zeitgibers. Potential for circadian disruption.


14 Normal Physiology and Sleep
Most physiologic functions follow the daily temperature cycle Alertness greatest when body temperature is at its physiologic peak, minimal when cortizol and temperature at their nadir


16 At Night, the unadjusted worker:
Performance for stimulating, high-attention tasks is unchanged Attention wanders for routine, non-demanding tasks “Daydreams” and micro-sleeps intrude “Code” performance ok, but subtle things missed.


18 Normal Sleep Architecture: Stages of sleep
Non-REM (NREM) sleep - Stages I-IV brain idle, body mobile REM - Body paralyzed, Brain active (more metabolically active than during waking!)

19 Stage 1 - transition period.
Normally 10 minutes. Eyes rove. Most people awakened during Stage 1 claim they are not asleep.

20 Stage 2 - Deeper, fewer eye movements.
Shallowest restorative sleep. About half of adult sleep in Stage 2. 20 min. before progressing to next stage.

21 Stages 3/4 - Slow wave sleep (SWS), (delta sleep)
Most restorative & restful; vital for physical recuperation. Majority occurs early in the sleep period. Difficult to arouse from SWS. First stage to be “made up” after sleep deprivation. SWS deprivation causes fatigue, muscle aches and worse.

22 REM sleep: brain on, body off
Vital for psychological well-being; May be critical for learning Isolated REM deprivation causes irritability, progresses to psychosis, then death EEG similar to wakefulness. Dreams, irregular pulse, respiration, increased BP, loss of muscle tone, and absent spinal reflexes.

23 REM sleep First episode occurs after 90-120 minutes of NREM sleep.
Recurs in about 90 minute cycles, getting more frequent towards awakening REM periods become longer as night progresses.

24 On Call versus On Duty


26 On Call On call: night work between working days = pure sleep deprivation Possibility of sleep while on call Main work is still during the daytime Usually does not cause circadian rhythm disruptions -- body cycles remain in phase Isolated night shifts (< 1 /week) function as ‘on call’

27 On Duty On duty implies time of usual type of work, not an isolated event Often called “Shift Work” Several common patterns Often a major cause of work dissatisfaction Nurses are more likely to have permanently assigned shifts than physicians (Unionized)

28 Circadian disruption Happens when waking / sleeping does not correspond with innate circadian rhythms Desynchronizes physiologic cycles Desynchronized systems cause significant physiologic and psychological malaise Sleep at the wrong time IS NOT equivalent to the same amount of sleep at the right time.

29 Chronic circadian disruption
Can cause life-long sleep problems Shortens life expectancy Worsens psychiatric problems Worsens interpersonal skills

30 Examples of circadian disruption
Jet lag: crossing time zones Shift work Hospitalization with loss of ‘Zeitgibers”--> “ICU Psychosis” “Sundowning” Even the most rapid physiologic parameters cannot adjust much faster than one or two hours per 24


32 Concept of “Zeitgibers”
Physical and social clues which tell us what time it is. Most powerful is light. Others include taste and smell of usual breakfast food, going to work, sound of daytime activities, social activities


34 Shift work Not a new phenomenon, but now vastly more frequent.
25% of American workers are shift workers at some point in their lives. Invention of the light bulb: 1883

35 Shift work Work a defined period of time, then off for a period
Working time can be at any time of the 24-hr day Fixed shifts -- working the same time every day Rotating shifts -- working time of day changes from time to time


37 Shift work in Industry Iron foundries and steel mills introduced shift with with rapid rotation. The chrono-stress gave impetus to unionism. Shift work is a major issue in union negotiations even today

38 Shift length Length of shift: most common is 8 hours
Others are 10, 12 and 6 hours More mistakes made in the last 4 hours of a 12 hour shift than in the first 8 hours Shift changes become more difficult after age 40

39 Do long shifts increase output per worker?
No. Ergonomics, the science of the Industrial Revolution Henry Ford first reduced working shifts from 12 hours to 8 hour Productivity increased Length of night shift more crucial than length of day shift

40 Serious adverse consequences of shift work
20% decrease in life span 62% sleep disturbance higher rate of accidents on the job high risks of fatal commuting accidents 800% risk of ulcers 1500% incidence of depression and mood swings


42 Shift work is also linked to:
drug and alcohol abuse altered immune response infertility in women high divorce rate.

43 Drug abuse

44 Shift work and the Heart
increased cardiovascular mortality (risk worse than smoking a pack of cigarettes per day) risk for dysrhythmias (PVC, MAT, SVT) risk of sinus arrest (up to 12 sec in one study) chronic hypertension

45 Tolerance to shift work
Better in younger persons (under 40, or pre-menopausal) Better in childless persons Better in natural owls than natural larks 20% of people have no trouble changing shifts, 60% have moderate hardship, and 20% have extreme difficulty.

46 Night People vs. Morning People
Night people = easier adjustment to shift work Tend to be phase delayed Day people = harder with shift change; more stable once adjusted Tend to be more synchronized and more resistant to re-setting Residency survey: EP s have more night types than normal populations

47 Shift length Most research has been done on 8 hr shifts
12 hour shifts no longer permitted in most industries

48 Why 8 hour shifts? Work output per physician (nurse) per hour is greater with 8 hour shifts. Mistakes less per worker with 8 hour shifts Patient satisfaction: patients more satisfied when health care worker is happy 12 hr shifts appeal most to younger, less experienced physicians / nurses

49 Worker wellbeing Optimum: days only
Next best: same shift every day, even if not most suited to your optimal time Acceptable: Isolated (night) shifts with core working time the same each day Worst of all: randomly rotating shifts

50 Shift rotation patterns
rotating (swing) shifts -- several common patterns “Isolated nights” work one shift regularly, with “isolated” different shifts no more than once per week randomly rotating shift -- any shift, any day, no pattern

51 Swing shifts (rotation patterns)
Phase advance: one week days, one week evenings, one week nights (can be monthly) Phase retreat: (Southern Swing): one week days, one week nights, one week evenings Phase advance is more physiologic and more easily tolerated “Owls” with their innate phase delay, acclimatize faster and tolerate phase advance better than “Larks”

52 Randomly changing shifts
almost universally condemned forbidden by most unions highest physiologic risk and stress practiced mostly by physicians

53 Isolated nights defined as less than one night per week
equivalent to a bad night on call

54 Adjusting to a new shift
Body can adjust by 1-2 hrs. / 24, or one week to move forward by one (8 hr) shift. Although weekly rotations are most common, a Monthly rotation is better, IF Worker will maintain the same sleep/wake schedule when not working

55 Downside Unfortunately, most permanent night workers switch to day-life when not at work Never acclimatize Same ill effects as random-shift changers

56 What about physicians? MD = Maximum Denial
Socialized to ignore their own needs Trained to be ‘tough’ poor role models

57 Performance of physicians
Åkerstedt et al: documented poor performance with micro-sleeps (non-restorative) during rote tasks documented micro and mini-sleeps during drive home even in those who did not think they had slept

58 Physician learning Asken MJ, Raham DC: Resident Performance and Sleep Deprivation: A Review. J. Med Educ 1983;58: Demonstrated decreased performance, learning of deleterious habits and physiologic harm.

59 Overall performance Tilley et al The sleep and performance of shift workers. Human Factors, 1982;24:624-41 Found that shift work affected rote tasks and the highest intellectual tasks equally as much; moderately challenging but well known tasks suffered least. Implication for physicians: we make more mistakes on the more serious cases

60 Implications for the efficient ED
8 hour shifts are optimal minimize circadian disruption through meticulous attention to circadian principles Non-sleep-disrupted physicians and nurses are more productive and less prone to drug or alcohol use, and therefore safer for patients and the employer

61 Strategies to improve efficiency of shift workers
Teach and encourage proper sleep hygiene (literature available upon request) Optimize shift rotation patterns Provide opportunities for food & exercise Encourage social life


63 Sleep Hygiene Keep sleep time sacred
Minimize care-giving responsibilities during sleep time. Optimize sleeping temperature Exercise 20 min per day, but at least 1 hr prior to going to sleep “When you feel least like doing it, is when you need it the most”

64 Diet Great care to eat appropriately during the working / waking time
Hospitals need to provide access to good, nutritious food for night workers as well as day workers Eating while socializing is a more powerful zeitgiber than eating alone.

65 Light: optimize single most powerful zeitgiber for humans
without adequate light, many humans never completely adapt to a new schedule intensity is important: 7,000 Lux, like a heavily overcast day most indoor lighting is inadequate

66 Light: problems new ‘energy saving’ fixtures are even more inadequate
Saving money by putting low output lighting in the Emergency Department is false economy. implication to hospital administration: high intensity lights over physicians / nurses working areas improves productivity and minimizes mistakes.

67 Optimize night-shift performance
Light ED at 7000 lux in at least some parts Scheduled night hours for the cafeteria -- adequate for everyone to get some while still staffing the ED Provide a quiet dark place for worker naps during breaks Exercise facilities on campus improves worker performance.

68 Scheduling to optimize worker performance
8 hour shifts Permanent night shift workers (days, evenings, nights) Night differential is helpful in recruiting permanent night workers Rotations: equal distribution of undesirable shifts

69 Creative scheduling: ultra short
Ultra-short night shift: night shift is only 6 hours long; it provides time for the worker to sleep before and after the shift. Minimizes circadian disruption. Works best with Isolated Night pattern and next best with Random Rotation

70 Creative Scheduling: split night
Split night: One shift ends very, very late (say 3 am) and the next starts very, very early (3 am) Each person gets to sleep part of the normal night time, and be up during most of the normal day. Excellent commuting conditions, too.

71 Exercise Athletes: get more delta (SWS, restorative) sleep.
Time of day important: pm exercise has more effect. Exercise should be over more than one hour before sleep time

72 Exercise implications for the workplace
Exercise at the workplace enhances alertness and worker wellbeing Brief episodes of vigorous exercise enhances alertness min in middle of the night Exercise improves sleep quality -- if completed at least 1 hour before sleep time Exercise before driving home -- fewer accidents during commute

73 Socialization An important zeitgiber for humans
Improves workforce wellbeing Social Life is main cause of night-workers NOT maintaining same schedule on days-off. Night workers need a social life, too Spouses must be supportive


75 The employer can: Encourage off-duty night workers to socialize during their normal waking hours Notify night workers of other night-time opportunities. Involve spouses in learning about shift work and sleep hygiene

76 Summary Emergency Medicine is of necessity 24 / 7
physicians, nurses, clerks, aides, housekeeping... Careful attention to circadian issues and shift scheduling can improve worker efficiency, improve retention, improve community relations, reduce medical mistakes...

77 Best single reference "Why we Sleep" by James Horne. Published by Oxford University Press Walton St Oxford OX2 6DP 1988 a classic overall reference


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