Fatigue Risk Management

Transcription

1 Fatigue Risk Management A safety management systems approach Professor Drew Dawson Criterion Conferences February, 2012

2 Comparative Risk: Fatigue vs Alcohol Alcohol Train Sleep Placebo Train Sleep Fatigue Train Sleep Sustained wakefulness Time of Day

3 Comparative Risk: Fatigue vs Alcohol 140% Cognitive Performance 120% 100% 80% 60%.05% BAC.10% BAC 40% Time of Day

4 biology of fatigue? 140% 120% 100% 80% 60% 40% Time Awake Time of Day

5 combined effect 140% Cognitive Performance 120% 100% 80% 60% 40% 20% 0% Clock time over 4 days

6 Cognitive effects of Fatigue Naturalistic Decision-making model Situational awareness Memory Simulation ability Performance insight Emotional Control

7 reduced situational awareness attentional tunnelling load shedding lapse hypothesis

8 Lapse hypothesis Attention 1 0

9 impaired memory performance impaired transfer from shortterm to long-term memory impaired procedural memory reduced ability to recall stored information

10 impaired performance insight reduced self-monitoring greater divergence from desired system state increased behavioural variability

11 reduced emotional control tired people are grumpy people terse communications increased authority gradients degraded mental models in team-based tasks reduced compliance with internalised SOP s

12 Political context Micro-economic reforms Work intensification extended commutes as in FIFO/DIDO OH&S reforms Fatigue as a safety hazard Risk management Safety management Parliamentary enquiries Midnight Oil (2000) FIFO/DIDO (2011-2)

13 Legal context Jiminez Decision in HCA Shift from diminished capacity to voluntary impairment Principle of reasonable forseeability Chain of responsibility legislation Liability cannot be outsourced

14 OHS context Fatigue identified as a specific workplace hazard Organisations required to implement a system to manage the hazard Shared responsibility framework Risk-based framework (i.e. AS 4360) element of the Safety management System (i.e. AS 4801)

15 The Challenge Long hours of work are an entrenched work practice Prescription can be paradoxical No single solution suitable for all groups

16 Defenses-in-depth approach Level 1 Level 2 Level 3 Level 4 Level 5

17 Cost-effectiveness Cost of single defensive layer as a function of effectiveness

18 Defenses-in-depth approach Effectiveness of level Level 1 Level 2 80% 60% 40% 20% 80% 60% 40% 20% Level 3 80% 60% 40% 20% E = 1- [1-L1]*[1-L2]*[1-L3]...*[1-Ln] 99.2% 93.4% 78.4% 48.8% Total Effectiveness

19 Shared Legal Responsibility for Fatigue Management is responsible for ensuring working arrangements provide a sleep opportunity sufficient to recommence fitfor-work. Employees are responsible for using a sleep opportunity to obtain sufficient sleep in order to be fit-for-work. Employees must notify line manager if this does not occur. Management is responsible for providing clear guidelines on how to manage an employee who is not fit-for-work.

20 Key elements of an FRMS FRMS policy Competency-based training and education program Compliance system for ensuring employees are fit-for-duty Audit system for ensuring the FRMS is operating as specified

21 Hazard Control Model Active Errors Latent Errors Sleep opportunity Obtained sleep Behavioral Symptoms Fatigue-related errors Fatigue-related incidents Rules of rostering Fatigue modeling Prior Sleep/Wake data Symptom checklists Self-report behavioral scales Physiological monitoring Fatigue-proofing strategies Error analysis system Incident analysis system

22 Level 1 Controls Primary purpose is a risk assessment to ensure sleep opportunities are adequate rules of rostering fatigue modelling

23 Level 1 Controls 5 key dimensions of the roster can be used to risk assess the sleep opportunities weekly hours shift duration break duration night work hours reset breaks

24 Assessing fatigue likelihood Roster dimension Max hours per 7 days 36h 36-43h 44-47h 48-54h 55+ Shift duration 8h 8-10h 10-12h 12-14h 14h Short break duration 16h 16-13h h 8h Max hours of night work per 7 days 0h 1-8h 8-16h 16-24h 24h Long break frequency 1/7d 1/7d 1/14d 1/21d 1/28d

25 Likelihood assessment Controls required As the sleep opportunity is reduced, the likelihood that an employee will be fatigued goes up as does the extent of the hazard controls required to control the risk

26 Fatigue modeling non-work non-work non-work S S W S W S W Timing and duration of work and non-work periods are used to estimate the most likely sleep-wake patterns and then the consequent level of work-related fatigue

27 Likelihood assessment using FAID Work period FAID scores across 12h night shift

28 Risk assessment using FAID model Risk Score Plan Actual Action Low <80 >97.5% >95% Moderate >99% >97.5% High % >99% Extreme % >1% None unless otherwise indicated Investigate and correct where high chance of reoccurence Investigate and correct if moderate chance of recurrence Notify regulator and provide corrective action within 14 days

29 Level 2 Controls Prior sleep (48h) Prior sleep (24h) sleep sleep work Prior wake X = the amount of sleep in the prior 24h Y = the amount of sleep in the prior 48h Z = the amount of wake since last sleep longer than 2h The less sleep and/or the greater wake the greater the likelihood you will exhibit signs and symptoms of fatigue

30 Calculate personal fatigue likelihood score (X score) For every hour of sleep less than 5h in 24 add 4 points (Y score) For every hour of sleep less than 12h in 48 add 2 points (Z score) For every hour of wake greater than the hours of sleep in the last 48h add 1 point Personal fatigue likelihood score = (5-X)*4 + (12-Y)*2 + (Z-Y) Microsoft XL formulae: PFLS = 44-4x-3y+z

31 14 pfls calibration 12 Struggling to stay focussed on tasks, difficulty concentrating, micro-sleeps likely 10 Clear loss of motivation. Sig. loss of situational awareness. Task performance impaired Clear evidence of behavioural impairment. Difficulty sustaining attention on simple tasks Difficulty concentrating. Occasional lapses of attention. Poor judgement on complex tasks Difficulty in maintaining extended concentration for complex tasks Slowed cognition. Occasional minor fatigue behaviours. Minor mood changes observable Not fully alert but able to perform tasks safely. Few external signs of fatigue pfls

32 Example 1 7h Sleep 4h Sleep Work Start End X = 4/24, 4(5-4) = Y = 11/48, 2(12-11) = Z = 2 or = Total = +6 +9

33 Example 2 6h Sleep 6h Sleep Work Start End X = 6/24, 4(5-6) = Y = 12/48, 2(12-12) = Z = 2 or = Total = +0 +2

34 Example 3 6h Sleep 6h Sleep Work Start End X = 6/24, 4(5-6) = Y = 12/48, 2(12-12) = Z = 11 or = Total =

35 Score Action 0 Do nothing unless indicated otherwise Minor increase in likelihood of fatigue. Notify co-workers and supervisors and undertake risk assessment for tasks with risk consequences greater than 4. Self management controls usually sufficient. Typical controls, self-monitoring, caffeine, task rotation, self paced work load. Moderate increase in likelihood of fatigue. Notify co-workers and supervisors and undertake risk assessment to continue tasks with risk consequence greater than 3. Team and process management controls usually sufficient. Increased supervision, task re-assignment. Signifiant increase in likelihood of fatigue. Notify co-workers and supervisors and undertake a risk assessment to continue tasks with a consequence greater than 1. Document in SMS report. Do not continue in any safety critical task without 1-up approval based on pre-existing risk assessment. Controls unlikely to be sufficient.

36 Level 3 controls behavioural measures response times hand-eye coordination eye movement brain waves (EEG) skin conductance (EDA) pupil dilation embedded measures GPS on-board computers black-boxes

37 Level 4 controls Other talk

38 Level 5 controls For an accident to be considered fatigue-related, two conditions must hold, There must be level 1-3 evidence of an increased likelihood of fatigue The error that caused the accident must be typical of a fatigue-related error