Longitudinal Evaluation of Multimodal Worker Fatigue Assessments in Offshore Shiftwork

Abstract

Fatigue in the workplace is a growing concern in industries and is seen as a work hazard that can impair workers’ physical and cognitive abilities. This leads to an increased number of incidents, injuries, and fatalities, thus reducing worker safety. Among offshore oil and gas workers, fatigue is a significant, but under addressed, physiological state owing to the nature of the work, hazardous work environments, intense shift work, and frequent shift rotations. A major barrier to understanding fatigue among offshore workers is the lack of systematic and longitudinal studies that monitor worker fatigue levels through measures that have the potential to be feasibly deployed in offshore operations and that support capturing fatigue outcomes associated with different sources (e.g., sleep, shift rotation, workload). This dissertation investigates the effectiveness and feasibility of using multimodal worker fatigue assessments to capture offshore oil and gas workers’ fatigue levels over the course of the workers’ stay on rigs (i.e., hitch) across two drillships in the Gulf of Mexico through three integrative aims: 1) to examine the changes in subjective, physiological, and performance-based fatigue measures over time across different shift types (day, night, and swing), 2) to assess perceived utility, effectiveness, and feasibility and actual compliance of daily worker completion of fatigue assessments over the same time period, and 3) to determine the impact of shift rotation on swing shift workers and their adaption to their new biorhythms using multimodal fatigue assessments. A key overall finding that fatigue related subjective measures, particularly those that are self-reported, do not consistently align with objective (physiological and performance) measures implicate the need for multimodal assessments. Based on a prior review of methods for monitoring and managing fatigue in offshore environments, the extant scientific evidence on performance-based fatigue measures, and the findings from the three aims, this dissertation offers two actionable research-to-practice recommendations, which include (1) supplementing self-reports on worker fatigue with sleep monitoring using actigraphy watches and administering short-duration performance tests (i.e., a 3- or 5-minute Psychomotor Vigilance Task) to evaluate fatigue level objectively on a daily basis; and (2) avoiding shift rotations, particularly from day to night shifts, where possible to minimize the impacts of circadian adjustments on worker readiness. These two recommendations, once evaluated, may be implemented as part of a fatigue risk management system, which can promote timely and effective fatigue management practices.