Raghu Upender, MD Assistant Professor in Neurology Medical Director Vanderbilt Sleep Disorders Center Fatigue Science & Safety Occupational Sleep Medicine

None None DISCLOSURES

EXXON VALDEZ

DRIVINGWHENDROWSY 71,000 non-fatal injuries occur per year 71,000 non-fatal injuries occur per year 1,550 fatal injures occur per year 1,550 fatal injures occur per year $12.5 billion in monetary losses $12.5 billion in monetary losses

How can we mitigate the risk of human error in risk of human error in future disasters?

Define fatigue and sleep Define fatigue and sleep Review effects of Sleep loss Review effects of Sleep loss Review sleep physiology Review sleep physiology Describe fatigue modeling Describe fatigue modeling Fatigue risk management Fatigue risk management OUTLINE

Physical or mental “exhaustion arising from labor, exertion, or stress” -Merriam-Webster Dictionary FATIGUE DEFINITION

FATIGUE SEVERITY SCALE

Fatigue ≈ performance degradation FATIGUE IN THE WORK PLACE

PVT is relatively brief, easy to administer, and can be repeated multiple times through the day. PVT is relatively brief, easy to administer, and can be repeated multiple times through the day. The PVT measures simple reaction time to a visual stimulus The PVT measures simple reaction time to a visual stimulus PVT reaction times correlate well with other cognitive tests. PVT reaction times correlate well with other cognitive tests. PSYCHOMOTOR VIGILANCE TEST

Doran SM, Van Dongen HPA, Dinges DF. Arch Ital Biol 2001;139: PVT REACTION TIMES

Saper CB et al. Nature 437, (27 October 2005) ASCENDING AROUSAL SYSTEM

Saper CB et al. Nature 437, (27 October 2005) SLEEP PROMOTING VLPO

Saper CB et al. Nature 437, (27 October 2005) FLIP FLOP SWITCH

Narcolepsy Narcolepsy Sleepiness intrudes into wakefulness due to Loss of orexin producing neurons leads to loss of orexin’s stabilizing effect on arousal Loss of orexin producing neurons leads to loss of orexin’s stabilizing effect on arousal Insomnia in the elderly Insomnia in the elderly Wakefulness intrudes into sleep due to age related loss of VLPO neurons leads to less effective suppression of arousal system. age related loss of VLPO neurons leads to less effective suppression of arousal system. CLINICAL EXAMPLES

During prolonged arousal During prolonged arousal – Arousal system weakens due to exhaustion – Sleep pressure accumulates – Wake promoting circuits are overwhelmed and abrupt transition to sleep occurs causing momentary lapse FLIP-FLOP SWITCH AND FATIGUE

Wesensten NJ, Thorne DR, et. Al. Aviat Space Environ med 2004;75: PVT SPEED AND SLEEP DEPRIVATION

Process S Process S Process C Process C SLEEP – WAKE REGULATION

– Sleep homeostatic drive – Increases during the wake period – Declines during sleep – Quantified by slow wave sleep PROCESS S

Taber KH et al. The Journal of Neuropsychiatry and Clinical Neurosciences 2006 CEREBRAL BLOOD FLOW ACROSS SLEEP STATES

PERFORMANCE RESERVOIR

Master Circadian oscillator Master Circadian oscillator Provides alerting signal Provides alerting signal PROCESS C

Richardson GS: The human circadian system in normal and disordered sleep. The Journal of Clinical Psychiatry 2005; 66(Suppl 9):3—9. THE TWO-PROCESS MODEL OF SLEEP REGULATION

PROCESS W PROCESS OF AWAKENING Balkin, TJ et al. Brain 2002;125:

Human error due to fatigue is fundamentally stochastic, i.e. random. Human error due to fatigue is fundamentally stochastic, i.e. random. Performance lapses that occur due to wake state instability are also stochastic. Performance lapses that occur due to wake state instability are also stochastic. Though the individual performance lapses in attention occur randomly, the probability at which they occur is predictable. Though the individual performance lapses in attention occur randomly, the probability at which they occur is predictable. BASIS FOR FATIGUE MODELING

FATIGUE MODEL

Belenky, G et. al. J Sleep Res Mar;12(1):1-12. PVT SPEED AND SLEEP TIME

Hursh SR. Aviat Space Environ Med 2004; 75:A44-53

FATIGUE VS. ACCIDENT RISK Hursh SR et al. SAE Trans 2004;113:

“I’m too tired to listen to a story right now, mom. Just something and I will read it tomorrow.”

Approximately 21% of adults average ≤ 6 hours of sleep Approximately 21% of adults average ≤ 6 hours of sleep 70 million American experience chronic sleep loss on a daily basis 70 million American experience chronic sleep loss on a daily basis Both acute and chronic sleep loss can have detrimental effects on performance Both acute and chronic sleep loss can have detrimental effects on performance Deficits in executive functions can lead to critical errors in the work place Deficits in executive functions can lead to critical errors in the work place SLEEP LOSS

“If you don’t think fatigue wreaks havoc, take a look at some of the laws we write around here at 1 a.m.” -Rep. James Oberstar (D-MN)

Coast Guard Coast Guard Federal Rail Road Administration Federal Rail Road Administration Federal Motor Carrier Administration Federal Motor Carrier Administration Federal Aviation Administration Federal Aviation Administration Health Care- ACGME Health Care- ACGME FATIGUE RISK MANAGEMENT

No specific Regulations at this time No specific Regulations at this time Rail Safety Improvement Act of 2008 (RSIA) requires railroads to develop Rail Safety Improvement Act of 2008 (RSIA) requires railroads to develop – Risk Reduction Program – Fatigue Management Plan RAIL ROAD

Total hours of service (HOS) per week = 70 Total hours of service (HOS) per week = 70 Daily driving limit = 11 Daily driving limit = 11 Continuous driving limit = 8 (30 minute break) Continuous driving limit = 8 (30 minute break) Two nights’ rest (1:00 am to 5:00 am)/week Two nights’ rest (1:00 am to 5:00 am)/week 34 consecutive hours of rest to restart 34 consecutive hours of rest to restart Company penalties- $11,000 per offence Company penalties- $11,000 per offence Driver Penalty- $2,75 per offence. Driver Penalty- $2,75 per offence. TRUCK DRIVERS

Varying flight and duty requirements based on what time the pilot’s day begins. Varying flight and duty requirements based on what time the pilot’s day begins. Flight duty period Flight duty period Flight time limits of 8-9 hours Flight time limits of 8-9 hours 10-hour minimum rest period 10-hour minimum rest period Cumulative Flight duty and flight Time limits Cumulative Flight duty and flight Time limits Fitness for duty Fitness for duty Fatigue risk management system Fatigue risk management system AVIATION

16 hr duty hour limit for 1 st year of residency 16 hr duty hour limit for 1 st year of residency 24 hr limit for subsequent years of residency 24 hr limit for subsequent years of residency Strategic napping encouraged Strategic napping encouraged 10 hrs off in between duty periods 10 hrs off in between duty periods 24 hrs off per 7-day period 24 hrs off per 7-day period 80 hour limit per week 80 hour limit per week Flexibility depending on specialty Flexibility depending on specialty RESIDENT DUTY HOURS

Predicts risk of impairment in a given schedule Predicts risk of impairment in a given schedule Function as a component of fatigue risk management systems that are mandated by law Function as a component of fatigue risk management systems that are mandated by law Guide the effective implementation of fatigue countermeasures Guide the effective implementation of fatigue countermeasures Allow more flexible and more effective scheduling then hours of service regulation Allow more flexible and more effective scheduling then hours of service regulation FATIGUE MODELING

Military Military Health Care Health Care Manufacturing Manufacturing First Responders (EMS, Police, Fire Fighters) First Responders (EMS, Police, Fire Fighters) Education Education Sports Sports POTENTIAL APPLICATIONS

Develop non-intrusive tools to measure performance in the operational environment Develop non-intrusive tools to measure performance in the operational environment Develop inexpensive tools to measure sleep quality and quantity over sequential sleep periods Develop inexpensive tools to measure sleep quality and quantity over sequential sleep periods Develop personalized fatigue management programs to reduce occupational risk and improve individual performance and well being. Develop personalized fatigue management programs to reduce occupational risk and improve individual performance and well being. FUTURE GOALS