SLEEP AND SAFETY AT WORK - DR HUGH SELSICK CONSULTANT IN PSYCHIATRY AND SLEEP MEDICINE INSOMNIA CLINIC UCLH/SLEEP CLINIC GUY'S HOSPITAL - IOSH
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SLEEP AND SAFETY AT WORK
DR HUGH SELSICK
CONSULTANT IN PSYCHIATRY AND SLEEP MEDICINE
INSOMNIA CLINIC UCLH/SLEEP CLINIC GUY’S HOSPITAL
GOALS • UNDERSTAND WHY SLEEP IS IMPORTANT FOR SAFETY AT WORK. • UNDERSTAND THE IMPACT OF SLEEP DEPRIVATION ON SAFETY. • BE AWARE OF THE IMPACT OF SOME COMMON SLEEP DISORDERS. • UNDERSTAND THE ROLE OF THE CIRCADIAN RHYTHM IN SAFETY AND PERFORMANCE.
SLEEP AND PERFORMANCE • THE PURPOSE OF SLEEP IS STILL A MYSTERY. • IT PROBABLY SERVES MULTIPLE FUNCTIONS WITH THE MAJORITY BEING RELATED TO MENTAL FUNCTION. • GOOD SLEEP IS ESSENTIAL FOR ALERTNESS AND VIGILANCE. • IT IS ALSO IMPORTANT FOR COGNITIVE FUNCTION.
SLEEP DEPRIVATION
• DEFINITION: INSUFFICIENT SLEEP DUE TO INSUFFICIENT SLEEP OPPORTUNITY.
• SLEEP DEPRIVATION MAKES YOU SLEEPY!
• PERFORMANCE ON PSYCHOMOTOR VIGILANCE TASKS DETERIORATES WITH SLEEP DEPRIVATION.
• THE DEGREE OF DETERIORATION CORRELATES WITH THE DEGREE OF SLEEP LOSS.
• THEREFORE WORK SCHEDULES THAT LEAD TO REPEATED SLEEP LOSS LEAD TO PROGRESSIVE DETERIORATION IN PERFORMANCE.
• FUNCTIONAL NEUROIMAGING STUDIES CONFIRM A GLOBAL REDUCTION IN CEREBRAL ACTIVITY, PARTICULARLY IN THE
PREFRONTAL CORTEX AND THALAMUS.
Van Dongen, 2016SLEEP DEPRIVATION (2)
• PERFORMANCE DEFICITS ARE NOT DUE TO A GENERAL DECLINE IN PERFORMANCE BUT DUE TO WIDENING TRIAL TO TRIAL
VARIABILITY.
• THEREFORE SUBJECTS ARE ABLE TO RESPOND NORMALLY IN SOME TRIALS BUT SHOW SIGNIFICANT DEFICITS IN OTHERS.
• THE SHIFT BETWEEN NORMAL AND IMPAIRED PERFORMANCE CAN BE VERY RAPID.
• TESTS OF THE IMPACT OF SLEEP DEPRIVATION ON PERFORMANCE NEED TO BE EXTENDED AS THIS VARIABILITY, COMBINED WITH
HIGH MOTIVATION, CAN LEAD TO FALSE NEGATIVES.
Hursh, 2016MANAGING SLEEP DEPRIVATION
• THE SINGLE BEST TREATMENT/PREVENTION FOR SLEEP DEPRIVATION IS SLEEP (DUH!).
• HOWEVER, IT CAN TAKE SEVERAL NIGHTS OF RECOVERY SLEEP TO REVERSE SLEEP DEPRIVATION AND THE ASSOCIATED
PERFORMANCE DEFICITS.
• IF YOU ACCUMULATE A SLEEP DEBT BY NOT GETTING ENOUGH SLEEP, CAN YOU PUT YOUR ACCOUNT IN CREDIT BY SLEEPING
LONGER THAN USUAL BEFORE THE PERIOD OF SLEEP DEPRIVATION?
• LONGER SLEEP MAY PROVIDE SOME PROTECTION FROM THE EFFECTS OF SUBSEQUENT SLEEP LOSS, BUT THE EFFECT IS
MODEST.
• SOME PEOPLE ARE LESS/MORE SUSCEPTIBLE TO THE EFFECTS OF SLEEP DEPRIVATION AND THIS CHARACTERISTIC IS STABLE.
Hursh, 2016THE ROLE OF THE CIRCADIAN RHYTHM • OUR INTERNAL BODY CLOCK CONTROLS OUR ALERTNESS DRIVE. • THE ALERTNESS DRIVE VARIES ACROSS THE 24 HOUR DAY. • PEAK ALERTNESS OCCURS AROUND 9PM AND MINIMUM ALERTNESS AROUND 4-5AM. • THIS ALERTING SIGNAL INTERACTS WITH ACCUMULATED SLEEP DEBT/FATIGUE TO DETERMINE HOW ALERT WE ARE.
CIRCADIAN RHYTHM AND PERFORMANCE
• WE PERFORM MORE POORLY WHEN OUR CIRCADIAN
ALERTNESS DRIVE IS LOW I.E. IN THE HOURS AROUND THE
4-5AM MINIMUM.
• MOST WORKPLACE ACCIDENTS AT NIGHT OCCUR DURING
THIS PERIOD.
• DRIVING BETWEEN 2 & 5AM CONFERS AN ALMOST 6X
GREATER RISK OF HAVING AN ACCIDENT.
Philip, 2016SHOULD NIGHT WORKERS BE ALLOWED TO SLEEP ON THE JOB? • EXPECTING WORKERS TO PERFORM WELL AROUND THE CIRCADIAN MINIMUM IS UNREALISTIC. • NIGHT WORKERS ARE UNLIKELY TO SLEEP AS WELL DURING THE DAY AS THEY WOULD AT NIGHT AND ARE LIKELY TO BE SLEEP DEPRIVED. • PLANNED NAP PERIODS MAY BE WISE. • BUT IN JOBS REQUIRING RAPID RESPONSE SLEEP INERTIA IS A CONSIDERATION.
INSOMNIA • DEFINITION: DIFFICULTY INITIATING OR MAINTAINING SLEEP, OR POOR SLEEP QUALITY NOT BETTER EXPLAINED BY ANOTHER SLEEP DISORDER, DESPITE ADEQUATE OPPORTUNITY AND LEADING TO DAYTIME DYSFUNCTION. • THE COMMONEST SLEEP DISORDER AFFECTING UP TO 10% OF ADULTS. • LEADS TO SIGNIFICANT REDUCTION IN PRODUCTIVITY, SLOWER CAREER ADVANCEMENT AND INCREASED ABSENTEEISM. • HAS A SIMILAR IMPACT ON QUALITY OF LIFE TO MAJOR DEPRESSION AND CHF (KATZ, 2002).
INSOMNIA AND DRIVING ACCIDENTS
• DATA ON THE ASSOCIATION BETWEEN INSOMNIA AND DRIVING ACCIDENTS IS EQUIVOCAL WITH SOME STUDIES FINDING NO
ASSOCIATION AND OTHERS FINDING A MARKED ASSOCIATION.
• INSOMNIA CAUSES FATIGUE BUT OFTEN NOT SLEEPINESS.
• INSOMNIA SUFFERERS MAY BE MORE LIKELY TO AVOID DRIVING.
• HOWEVER, THE DATA ON WORKPLACE ACCIDENTS IS UNEQUIVOCAL WITH STUDIES SHOWING A BIG IMPACT OF INSOMNIA
ON WORKPLACE ACCIDENTS.
• THIS MAY REFLECT THE FACT THAT PROGRESSIVE FATIGUE COMES INTO PLAY IN THE WORKPLACE.
Leger, 2010INSOMNIA IN THE WORKPLACE
• LEADS TO SIGNIFICANT REDUCTION IN PRODUCTIVITY, SLOWER CAREER ADVANCEMENT AND INCREASED ABSENTEEISM.
• PRODUCTIVITY: E.G. ESTIMATED TO HAVE COST U.S. ECONOMY IN 1988 $41 BILLION.
• ABSENTEEISM CONSISTENTLY FOUND TO BE DOUBLE THE RATE IN GOOD SLEEPERS. INSOMNIA MAY BE THE STRONGEST
PREDICTOR OF ABSENTEEISM.
• MAY INCREASE THE RATE OF WORKPLACE ACCIDENTS BY UP TO 8X.
• HYPOTHESISED THAT INCREASED ABSENTEEISM AND REDUCED PRODUCTIVITY MAY INCREASE THE RISK OF WORKPLACE
ACCIDENTS IN GOOD SLEEPER CO-WORKERS.
Leger, 2010HYPNOTICS AND SAFETY
• BY DEFINITION, HYPNOTICS ARE SEDATIVE DRUGS.
• SEDATIVES MAY LEAD TO DAYTIME SEDATION.
• MOST WORK HAS BEEN DONE ON HYPNOTICS AND DRIVING.
• LONGER ACTING HYPNOTICS KNOWN TO AFFECT DRIVING PERFORMANCE THE NEXT MORNING E.G. ZOPICLONE (!)
• SHORTER ACTING DRUGS SAFER E.G. ZOLPIDEM.
• SEDATIVE ANTIDEPRESSANTS WIDELY USED FOR INSOMNIA. LONG HALF LIVES AND CAN LEAD TO REDUCED DRIVING
PERFORMANCE IN THE INITIATION STAGE (POSSIBLY NOT MIRTAZAPINE); NO EFFECT ONCE SETTLED ON THE DRUG.
Philip, 2016OBSTRUCTIVE SLEEP APNOEA • DEFINITION: REPEATED PARTIAL OR TOTAL COLLAPSE OF THE UPPER AIRWAY DURING SLEEP LEADING TO HYPOXIA AND/OR AROUSALS. THIS LEADS TO BOTH SLEEP DISRUPTION AND MULTIPLE CARDIOVASCULAR, ENDOCRINE, PSYCHIATRIC AND NEUROLOGICAL SEQUELAE. • COMMONLY, BUT NOT UNIVERSALLY, CAUSES EXCESSIVE DAYTIME SLEEPINESS.
OSA AND ACCIDENTS
• DRIVERS WITH AN APNOEA/HYPOPNEA INDEX (AHI) >10/HR HAD AN OR OF 6.3 (CI 2.4-16.2) FOR HAVING AN ACCIDENT
RELATIVE TO NORMAL SLEEPERS.
• SOME STUDIES HAVE FOUND ACCIDENTS ONLY HIGHER IN SEVERE OSA (AHI>30/HR).
• BUT OTHERS HAVE FOUND AN INCREASED RISK OF ACCIDENTS NOT DEPENDENT ON SEVERITY OF OSA.
• THIS MAKES IT DIFFICULT TO KNOW AT WHAT LEVEL OF OSA SHOULD TRIGGER CONCERN.
• CPAP TREATMENT REDUCES THE RISK OF ACCIDENTS.
Philip, 2016; Zhang,
2016OSA IN THE WORKPLACE
• OSA IS STILL UNDIAGNOSED AND OFTEN WILL ONLY COME TO MEDICAL ATTENTION AFTER AN UNTOWARD INCIDENT.
• IT IS THE COMMONEST MEDICAL CAUSE OF EXCESSIVE DAYTIME SLEEPINESS.
• IT CAN LEAD TO REVERSIBLE AND NON-REVERSIBLE COGNITIVE DEFICITS.
• IT IS ASSOCIATED WITH 2X RISK OF WORKPLACE ACCIDENTS.
• COSTS TO ECONOMY FROM WORKPLACE ACCIDENTS, ABSENTEEISM AND REDUCED PRODUCTIVITY ASSOCIATED WITH OSA IN
REGION OF $10-45 BILLION.
Zhang, 2016ASSESSING SLEEPINESS • THE MOST WIDELY USED MEASURE IS THE EPWORTH SLEEPINESS SCALE. • CUT-OFF BETWEEN NORMAL AND EXCESSIVE SLEEPINESS 9 - 11. • RELIES ON AN HONEST ASSESSMENT BY THE PATIENT AND GETTING A COLLATERAL ESS IS WISE.
OBJECTIVE MEASURES • MULTIPLE SLEEP LATENCY TEST: MEASURES SLEEPINESS. 4 OR 5 X 20 MINUTE NAP OPPORTUNITIES WHERE THE PATIENT TRIES TO FALL ASLEEP. MEAN SLEEP LATENCY 8 MINUTES OR LESS = EXCESSIVELY SLEEPY. • MAINTENANCE OF WAKEFULNESS TEST: 4 TRIALS X 40 MINUTES WHERE PATIENT TRIES TO STAY AWAKE. MEAN SLEEP LATENCY LESS THAN 8 MIN = PATHOLOGICAL SLEEPINESS; MEAN LATENCY GREATER THAN 40 MIN = NORMAL; BETWEEN 8 & 40 MIN???? • OXFORD SLEEP RESISTANCE TEST: 3-4 X40 MINUTE TRIALS WHERE PATIENT PRESSES A BUTTON IN RESPONSE TO A LIGHT EVERY 3SEC. 7 CONSECUTIVE MISSES CORRELATES WITH SLEEP. • DRIVING: SIMULATORS OR REAL WITH LANE DRIFT MONITORING.
MANAGING SLEEPINESS
• SLEEP – ENSURE ADEQUATE SLEEP BETWEEN SHIFTS. BE AWARE OF THE ROLE THAT SOCIAL AND ENVIRONMENTAL FACTORS
PLAY AS WELL AS CIRCADIAN RHYTHM.
• CAFFEINE IS EFFECTIVE (RECOMMENDED DOSE OF 150-200MG).
• MODAFINIL IS EFFECTIVE BUT ONLY LICENSED FOR PRIMARY HYPERSOMNOLENCE (NARCOLEPSY/IDIOPATHIC
HYPERSOMNOLENCE).
• BRIGHT LIGHT, ESPECIALLY BLUE LIGHT, IS A PROMISING INTERVENTION.
Philip, 2016PREVENTING SLEEPINESS • GOOD SCREENING PROGRAMMES IN THE WORKPLACE TO DETECT AND TREAT SLEEP DISORDERS. E.G.. 78% OF COMMERCIAL DRIVERS WITH BMI>32 HAVE CONFIRMED OSA, 47% WERE SLEEPY ON MSLT, BUT 100% DENIED SYMPTOMS OF OSA (DAGAN, 2006). • TECHNOLOGY TO MONITOR COMPLIANCE WITH TREATMENT E.G. CPAP CAN BE MONITORED REMOTELY. • FATIGUE RISK MANAGEMENT SYSTEMS: BIOMATHEMATICAL MODELLING UTILIZING MONITORING OF FATIGUE, SLEEP AND SHIFT PATTERNS, CIRCADIAN RHYTHM AND TIME ON TASK WITHIN THE JOB TO PREDICT AND MITIGATE RISK. CAN PROVIDE BROAD STRATEGIES FOR WORKPLACES AS WELL AS INDIVIDUALISED STRATEGIES FOR EACH WORKER.
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