筋収縮後の再酸素化実験に関する研究

博甲第38号生命システム科学博士県立広島大

Characterizing the Biomechanical Exposures Associated with Common and High Demand Personal Support Worker Tasks

Background: The physical demands that personal support workers (PSWs) are exposed to are increasing as our population ages and our society is increasingly shifting to at-home care, resulting in increases in workload demands. However, PSWs are also developing high rates of musculoskeletal disorders (MSD) likely because of increased exposure to physical task demands. There is a need to intervene to protect these essential healthcare workers. Presently, little is known about the biomechanical exposure characteristics associated with PSW work tasks, especially within a home care setting. PSW work is highly dynamic and a wide range of tasks with different loading scenarios are completed. This means that the time-series exposure patterns are also likely varied over a work shift or work week, where this variation may be important when designing effective ergonomic interventions. As an example intervention strategy, workload management may be an effective approach to monitor, assess, and redistribute workload as needed to provide recovery windows to reduce and mitigate the accumulation of exposure. Real-time tracking and the continuous monitoring of PSW exposures, or surrogates, may assist in the assessment of injury risk. To better understand the biomechanical exposure characteristics associated with common PSW work tasks and to explore the potential utility of ratings of perceived exertion (RPE) as a potential surrogate measure to track PSW workload, this thesis aimed to address the following two objectives and corresponding research questions: Objectives: 1. Characterize biomechanical exposure metrics associated with the performance of common and highly demanding PSW work tasks. 2. Evaluate the relationship between RPE and the biomechanical exposure metrics. Research Questions: 1. What are the biomechanical exposures experienced by PSWs when performing simulated common and physically demanding work tasks? 2. What is the relationship between RPE and biomechanical exposure metrics (peak low back flexion angle, peak low back extensor moment, cumulative low back extensor moment) when performing common and physically demanding PSW work tasks? Methods: Twenty PSWs were recruited to complete 12 work tasks within a laboratory setting, where full body kinematics and hand forces were collected for all trials. A whole-body top-down rigid link modelling approach was used to calculate biomechanical exposure metrics. Peak low back flexion angle along with peak and cumulative extensor moments were calculated. Linear regressions tested for relationships between post-task RPE scores and 1) peak low back angles, 2) peak low back extensor moment, and 3) cumulative low back extensor moment at an individual level, where corresponding regression statistics from each participant were the aggregated at the group level. Results: Patient handling tasks, such as transfers and repositioning tasks, had the highest peak extensor moments (ranging from 115-157 Nm), while having the lowest cumulative moment values (1329 – 4552 Nm*s). In contrast, patient care tasks such as bathing, dressing/undressing, and compression stocking application, had the highest cumulative extensor moment values (2623 – 8089 Nm*s) and lower peak moments (92 – 107 Nm). Additionally, patient care tasks took the longest to complete and required participants to frequently adopt moderate (20-45 degrees) to severe (>45 degrees) levels of low back flexion. A significant moderate positive relationship was found between RPE scores and cumulative low back extensor moment (p<0.05, R=0.60). No significant relationship was found between RPE scores and both peak low back flexion angle (p<0.05, R=0.16) and peak low back extensor moment (p<0.05, R=-0.13). Discussion: The biomechanical exposure characteristics of PSW work are task dependent. Patient handling tasks subjected PSWs to high peak loads for brief periods of time. Patient care tasks, on the other hand, imposed lower magnitudes of loading for extended time duration. It is well established that low back injury pathways are different when loading is high, but brief, relative to lower in magnitude, but sustained. As such, it appears that groupings of tasks may be of more interest to consider and intervene from the perspective of reducing high peak loads, where others might be better viewed from a cumulative load perspective. Therefore, in the design and development of any effective ergonomic interventions, it may be important to consider task-specific loading profiles and how they may influence injury development based on corresponding pathways. Task characterization as quantified within the current study can serve as a foundation to inform workflow management and patient scheduling decisions in an attempt to optimize temporal aspects of loading. RPE scores could be used as a surrogate for cumulative low back extensor moment, which may have utility as an easy-to-implement assessment tool to track the accumulation of spine extensor moment loading. These findings can inform additional work to evaluate how real-time RPE tracking functions within real work settings and can explore other metrics that might help to better monitor and track exposures during short duration, high load tasks

A new perspective on the design of pressure relief cushions for those with spinal injuries

The aim of this study is to develop new insights which pressure relief (PR) cushion designers can use to guide the design of new cushions with greater efficacy at preventing pressure ulcers than contemporary cushions. A methodological framework was formulated which incorporated a number of research techniques from the user-centred methodology USERfit, and included methodological triangulation. Exploratory interviews and observational work were conducted in a specialist unit for spinal cord injury (SCI). This involved ten patients, four physiotherapists, two nurses and an outpatient technician. Additionally, two questionnaires were designed and circulated amongst SCI patients and staff with completed responses from 41 patients and 31 staff. From the analyses of the data gathered from the literature, observational work, interviews and questionnaire responses, 28 recommendations for cushion design were formulated. These recommendations covered the principles which underpin cushion design, cushion usability and the future direction of cushion design

Examining work-related injuries of healthcare workers using lost-time claims, risk perceptions, photovoice, safety climate, and participatory ergonomics as data sources

The purpose of this dissertation was to examine work-related injuries of healthcare workers. Chapter 2 analyzed Workers Safety and Insurance Board (WSIB) claims data from 2004-2009 for three occupational roles (registered nurses, registered nursing assistants, and nurse aides and orderlies) working in Ontario hospitals and long-term care homes. Chapter 2 also explored changes in the body part affected, nature of injury, and accident type. Chapter 3 data described the risk perceptions of healthcare workers in long-term care. Chapter 4 utilized the Photovoice method for identifying patient lift and transfer risk factors. Chapter 5 assessed the safety climate and implemented participatory ergonomics programs in two long-term care homes. Chapter 2 found that the number of claims remained consistent from 2004-2009 for the occupational roles in Ontario hospitals and long-term care homes. The most common body part associated with reported injuries was the trunk/back. The most common nature of injury reported was strains, sprains and tears. The most common accident type was overexertion injuries, when further analyzed the most common tasks attributed to injuries were lifting and pushing or pulling. Chapter 3 found that healthcare workers did not appear to have the ability to identify risk, as there was little to no differentiation in the perceptions for the common causes and tasks. The lack of differentiation was in contrast to the WSIB data in Chapter 2 that clearly illustrated that overexertion injuries were the majority of accident types reported in claims. If healthcare workers do not accurately assess their risk of injury, they may not behave in a manner that avoids hazardous situations. As a result, they are placing themselves at an increased risk of injury. Chapter 4 illustrated that Photovoice was a valuable method for identifying risk factors as the approach stimulated discussion, provided visual evidence, and did not create additional paperwork for healthcare workers. Chapter 5 indicated that prior to implementing a participatory ergonomics program the ergonomist should assess the safety climate of the organization as this can help dictate the necessary steps and structure of the participatory ergonomics process

Design of innovative clothing for pressure injury prevention: end-user evaluation in a mixed-methods study

The global relevance of pressure injury (PI) prevention technologies arise from their impact on the quality of life of people with limited mobility and the costs associated with treating these preventable injuries. The purpose of this mixed methods study is to evaluate the design of a prototype integrating Smart Health Textiles for PI prevention based on feedback from specialist nurses who care for individuals who are prone to or have PIs. This is a mixed methods study. A structured questionnaire was conducted as part of an evaluation of a prototype garment for the prevention of PIs. This questionnaire was applied during the evaluation of the prototype and afterwards focus group discussions were held with experts. Descriptive statistics techniques were used to analyze the data and thematic and integrated content analysis was conducted through concomitant triangulation. Nineteen nurses took part, aged 30 to 39 years (52.6%) and with 12.31 ± 8.96 years of experience. Participants showed that the prototype required more manipulation and physical effort, which interfered its usefulness, in addition to presenting difficulties with the openings and the material of the closure system, which interfered with the ease of use and learning. Overall satisfaction with the product was moderate, with some areas for improvement found, such as satisfaction, recommendations to colleagues, and pleasantness of use. It is concluded that areas for improvement have been found in all dimensions, including in the design of openings and the choice of materials. These findings supply significant insights for improving clothing to meet the needs of healthcare professionals and patients.The 4NoPressure project was co-financed by the Operational Program for Competitiveness and Internationalization (COMPETE 2020) under the PORTUGAL 2020 Partnership Agreement, with support from the European Regional Development Fund (ERDF), reference number POCI-01-0247- FEDER-039869

An Assessment of the Interplay between the Shoulders and the Low Back in Occupational Tasks: A Manual Patient Handling Example

Redundancy and variation are characteristics of humans. Many muscles contribute to producing a movement at a joint, allowing different strategies for task performance. Further, the shoulders and back are involved in many tasks, including manual materials handling, but flexibility as to their relative roles in performing a task exists. In nursing, where manual patient handling (MPH) occurs daily, a risk of injury exists resulting from interactions with patients that may require awkward postures or sudden shifts in hand forces. Although some recommended MPH techniques have been advocated, many focus on lowering the risk of low back injury, without considering the effect of these techniques on other body regions. This study aimed to identify differences in shoulder and back physical exposures between performing self-selected and recommended patient handling techniques designed to reduce low back exposures. Twenty female participants performed three repetitions of five manual patient handling tasks using a self selected technique, followed by three repetitions of the same tasks using techniques learned in an interposed training session. Peak, mean and cumulative muscle activity, peak resultant moment, and ratings of perceived exertion were compared for each of the tasks before and after training, as well as identifying meaningful changes between the joints in mean population strength using a static strength prediction program. Significant decreases occurred at both the left and right shoulders and the low back for most measures, generally supporting the recommended techniques. Important exceptions existed, however, for the Sit-to-Chair tasks and Turn Toward tasks, where increases in several individual shoulder muscle activities, along with peak resultant moment, existed. Future recommendations for patient handling techniques should take into account potential negative exposures at the shoulders that may result from a back-centric injury avoidance paradigm

YouTransfer, YouDesign: A participatory approach to design assistive technology for wheelchair transfers

Transferring independently to and from their wheelchair is an essential routine task for many wheelchair users but it can be physically demanding and can lead to falls and upper limb injuries that reduce the person’s independence. New assistive technologies (ATs) that facilitate the performance of wheelchair transfers have the potential to allow wheelchair users to gain further independence. To ensure that users’ needs are addressed by ATs, the active involvement of wheelchair users in the process of design and development is critical. However, participation can be burdensome for many wheelchair users as design processes where users are directly involved often require prolonged engagement. This thesis makes two contributions to facilitate wheelchair users’ engagement in the participatory design process for ATs, while being mindful of the burden of participation. The first contribution is a framework that provides a modular structure guiding the participatory design process from initial problem identification and analysis to facilitating collaborations between wheelchair users and designers. The framework identifies four factors determining the need and adoption process for ATs: (i) People focuses on the target population, (ii) Person includes personal characteristics, (iii) Activity refers to the challenges associated with the task, and (iv) Context encompasses the effect of the environment in which the activity takes place. The second contribution constitutes a rich picture of personal and external elements influencing real world wheelchair transfers that emerged from four studies carried out to investigate the effect of the framework factors on the design process for ATs. A related outcome based on these contributions is a framing document to share knowledge between wheelchair users and designers to provide focus and promote an equal collaboration among participants