Shift Work and the Efficient ED

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 25-26 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