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 structureDefinitions 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 DefinitionsChronodisruption -- 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 sleepSleepiness -- 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 MedicineMedicine 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 cycleOther 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 SWSCore sleep: about 5 hours for most personsOnly core sleep made up.
11 Sleep deprivationloss 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 deprivationSleep 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 rhythmOn 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 cycleAlertness 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 unchangedAttention 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 mobileREM - 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 learningIsolated REM deprivation causes irritability, progresses to psychosis, then deathEEG 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 awakeningREM periods become longer as night progresses.
26 On CallOn call: night work between working days = pure sleep deprivationPossibility of sleep while on callMain work is still during the daytimeUsually does not cause circadian rhythm disruptions -- body cycles remain in phaseIsolated night shifts (< 1 /week) function as ‘on call’
27 On DutyOn duty implies time of usual type of work, not an isolated eventOften called “Shift Work”Several common patternsOften a major cause of work dissatisfactionNurses are more likely to have permanently assigned shifts than physicians (Unionized)
28 Circadian disruptionHappens when waking / sleeping does not correspond with innate circadian rhythmsDesynchronizes physiologic cyclesDesynchronized systems cause significant physiologic and psychological malaiseSleep 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 problemsShortens life expectancyWorsens psychiatric problemsWorsens interpersonal skills
30 Examples of circadian disruption Jet lag: crossing time zonesShift workHospitalization 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 dayFixed shifts -- working the same time every dayRotating shifts -- working time of day changes from time to time
37 Shift work in IndustryIron 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 hoursMore mistakes made in the last 4 hours of a 12 hour shift than in the first 8 hoursShift changes become more difficult after age 40
39 Do long shifts increase output per worker? No.Ergonomics, the science of the Industrial RevolutionHenry Ford first reduced working shifts from 12 hours to 8 hourProductivity increasedLength of night shift more crucial than length of day shift
40 Serious adverse consequences of shift work 20% decrease in life span62% sleep disturbancehigher rate of accidents on the jobhigh risks of fatal commuting accidents800% risk of ulcers1500% incidence of depression and mood swings
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 personsBetter in natural owls than natural larks20% of people have no trouble changing shifts,60% have moderate hardship, and20% have extreme difficulty.
46 Night People vs. Morning People Night people = easier adjustment to shift workTend to be phase delayedDay people = harder with shift change; more stable once adjustedTend to be more synchronized and more resistant to re-settingResidency 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 shiftsPatient satisfaction: patients more satisfied when health care worker is happy12 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 timeAcceptable: Isolated (night) shifts with core working time the same each dayWorst 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 weekrandomly 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 eveningsPhase 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 condemnedforbidden by most unionshighest physiologic risk and stresspracticed 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, aMonthly rotation is better, IFWorker will maintain the same sleep/wake schedule when not working
55 DownsideUnfortunately, most permanent night workers switch to day-life when not at workNever acclimatizeSame ill effects as random-shift changers
56 What about physicians? MD = Maximum Denial Socialized to ignore their own needsTrained to be ‘tough’poor role models
57 Performance of physicians Åkerstedt et al:documented poor performance with micro-sleeps (non-restorative) during rote tasksdocumented micro and mini-sleeps during drive home even in those who did not think they had slept
58 Physician learningAsken 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 performanceTilley et al The sleep and performance of shift workers. Human Factors, 1982;24:624-41Found 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 optimalminimize circadian disruption through meticulous attention to circadian principlesNon-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 patternsProvide opportunities for food & exerciseEncourage social life
63 Sleep Hygiene Keep sleep time sacred Minimize care-giving responsibilities during sleep time.Optimize sleeping temperatureExercise 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 workersEating 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 scheduleintensity is important: 7,000 Lux, like a heavily overcast daymost 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 partsScheduled night hours for the cafeteria -- adequate for everyone to get some while still staffing the EDProvide a quiet dark place for worker naps during breaksExercise facilities on campus improves worker performance.
68 Scheduling to optimize worker performance 8 hour shiftsPermanent night shift workers (days, evenings, nights)Night differential is helpful in recruiting permanent night workersRotations: 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 wellbeingBrief episodes of vigorous exercise enhances alertness min in middle of the nightExercise improves sleep quality -- if completed at least 1 hour before sleep timeExercise before driving home -- fewer accidents during commute
73 Socialization An important zeitgiber for humans Improves workforce wellbeingSocial Life is main cause of night-workers NOT maintaining same schedule on days-off. Night workers need a social life, tooSpouses must be supportive
75 The employer can:Encourage off-duty night workers to socialize during their normal waking hoursNotify 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 1988a classic overall reference
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