P106 The contribution of workload to fatigue risk in helicopter Search and Rescue operations

Abstract Introduction Routine offshore aviation transport services often co-provide Search and Rescue (SAR) operations. SAR crewmembers are required to be on immediate or standby readiness 24-hours a day and perform complex high-risk tasks when called. This study investigated work and sleep-based factors associated with workload and the contribution of those same factors to fatigue in this operation. Methods Across two 21-day rosters, SAR crewmembers recorded sleepiness (Karolinska Sleepiness Scale, KSS), fatigue (Samn-Perelli Fatigue Checklist, SP) and workload ratings (Overall Workload, OW and NASA Taskload Index, NASATLX), wore an actigraph to measure sleep, and completed a 3-minute Psychomotor Vigilance Task (PVT). Mixed model ANCOVAs investigated sleep and work-related factors associated with OW and NASATLX ratings and separately work-related factors associated with KSS and SP ratings and PVT performance at the end of a shift. Results A callout or training during a shift resulted in higher OW and NASATLX ratings (all p=<0.001). If a shift involved administration, OW and NASATLX were lower (all p≤.05). Prior sleep/wake history and shift worked were not significantly associated with workload measures. End of shift fatigue ratings were higher when a callout or training occurred, and end of shift sleepiness ratings were higher when training occurred (all p≤.05). Administrative work was not associated with changes in fatigue or sleepiness. No work-based factors were associated with PVT. Discussion Key contributors to both increased workload and greater fatigue and sleepiness were callouts and training. These aspects of work may directly impact fatigue and sleepiness and also indirectly, via greater workload.