Understanding Vibration Injury

描述(申请人提供)：拟议的研究目标与国家职业研究议程的国家建设议程中的肌肉骨骼疾病战略目标7.0保持一致，以降低美国建筑工人与工作相关的肌肉骨骼疾病的发生率和严重程度。根据美国劳工局的统计数据和公布的流行病学数据，估计有150万工人在建筑、制造业、农林和渔业使用电动工具，这些工人目前暴露在手臂振动水平之下，这使他们在工作10年后患上手臂振动综合症(HAVS)的风险高达10-50%。HAVs的主要神经和动脉病变是虚弱的麻木和手指的血流量减少。方法：在研究中将人类暴露在破坏性振动中是不道德的，因此具有与人类手指相似的神经和动脉结构和功能的动物模型是必不可少的。采用了两种鼠尾振动模型：一种模拟正弦振动，另一种模拟手臂振动的脉冲冲击波分量。评估了导致HAVS的振动频率(Hz)、加速度(m/s2R.M.S.)、振幅(Mm)和持续时间(振动/天和天数)等危险因素。我们最新开发的脉冲冲击波模型提供来自铆接锤的0.5赫兹到超过21千赫的振动分量，产生许多冲击工具所特有的冲击波振动。冲击波振动损伤早在90多年前就被人们认识到，但一直被忽视。必须解决这一知识差距，因为严重的甲型肝炎可能在2.5个月内发病，而非冲击性动力工具需要数年才能形成。正弦振动一直是振动研究的主要焦点，因为大多数工具的主要频率都在30-250赫兹范围内，而大多数HAVS都归因于此。人们忽视了这样一个事实，即非冲击性工具会产生冲击波，尽管不那么频繁。铆钉锤、削石机、石材切割机、冲击钻机和道路破碎机等冲击工具在每个占空比中都会产生冲击波脉冲。拟对振动大鼠尾巴的研究定量研究频率、加速度、幅度和持续时间与皮肤、动脉和骨骼肌神经结构损伤的关系，以及与感觉丧失和肌肉无力有关的功能缺陷(神经传导速度、von Frey触觉、热敏感性、冷浸泡刺激、复温和血流恢复)。本研究的目的有4个：1研究持续时间、频率、加速度和幅值对大鼠尾正弦振动模型持续血管收缩作用的剂量效应；2确定冲击波暴露时间与神经和动脉组织损伤程度的剂量反应关系；3通过重复测量，评价每天12分钟的冲击波振动后1天、1周和10周大鼠尾部神经和血液供应功能障碍的发生和可恢复性。目的4评价每天12分钟冲击波振动1d、1周和10周后，大鼠尾部神经和血液供应的振动性结构性损伤的发生和恢复情况。对现有范式的挑战：需要关于冲击振动的数据是至关重要的，因为现有的国际标准ISO 5349在风险计算中没有考虑脉冲振动和高频成分，因此，该标准严重低估了对工人的伤害。ISO 5349减弱了高频的贡献，因为研究报告说，人类不会“感觉”到1000赫兹的振动。预期结果：这项拟议的研究将证明“你感觉不到的东西也会伤害你”。剂量反应数据将有助于制定保护工人的循证指南，并挑战制造商消除令人讨厌的振动。我们的合作者董博士在位于西弗吉尼亚州摩根敦的NIOSH研究实验室工作，他将测试防振手套保护的有效性，并开发新的工程方法来测量工作场所的冲击振动，以便监控暴露。改变工作场所保护的障碍：拟议的研究结果将促进对正弦和冲击波振动对组织损伤的剂量反应关系的理解。这些数据将指导制定干预措施，降低工作场所手臂振动损伤的风险。

DESCRIPTION (provided by applicant): The goal of the proposed research aligns with the Musculoskeletal Disorders Strategic Goal 7.0 in the National Construction Agenda of the National Occupational Research Agenda to reduce the incidence and severity of work-related musculoskeletal disorders among construction workers in the U.S. Based on U.S. Bureau of Labor statistics and published epidemiological data, an estimated 1.5 million workers use powered tools in the construction, manufacturing, agriculture-forestry and fishing, and mining Sectors and are currently exposed to levels of hand-arm vibration putting them at risk for developing hand-arm vibration syndrome (HAVS) with a prevalence of 10-50% after working 10 years. The major nerve and artery pathologies of HAVS are debilitating numbness and reduced blood flow in the fingers. The Approach: Exposing humans to damaging vibration in a research study is unethical so animal model surrogates with nerves and arteries similar in structure and function to those in human fingers are essential. Two rat-tail vibration models are utilized: one simulating the sinusoidal and the other simulating impulse shock wave components of hand-arm vibration. The risk factors of vibration frequency (Hz), acceleration (m/s2 r.m.s.), amplitude (mm) and duration (vibration/day and days of vibration) that lead to HAVS are assessed. Our newly developed, impulse shock wave model delivers vibration with 0.5 Hz to over 21 kHz components from a riveting hammer that generates shock wave vibration characteristic of many impact tools. Shock wave vibration injury, recognized over 90 years ago, has been neglected. This knowledge gap must be addressed because severe HAVS can onset in 2.5 months compared to taking years to develop from non-impact powered tools. Sinusoidal vibration has been the major focus of vibration research because most tools have a dominant frequency in the 30-250 Hz range to which most HAVS has been attributed. Overlooked is the fact that non-impact tools generate shock waves albeit less regularly. Impact tools, such as riveting hammers, chippers, stone cutters, impact drills and road breakers, generate shock wave pulses with each duty cycle. The proposed studies of the vibrated rat-tail investigate quantitatively the relationships of frequency, acceleration, amplitude and duration to structural damage of the innervation of skin, artery and skeletal muscle and the functional deficits related to loss of feeling and muscle weakness (nerve conduction velocity, von Frey touch perception, thermal sensitivity, and cold immersion provocation rewarming and return of blood flow). The proposed research investigates 4 aims: Aim 1 To investigate the dose response of duration, frequency, acceleration and amplitude on the induction of persistent vasoconstriction in the rat-tail sinusoidal vibration model, Aim 2 To define the dose response relationship of shock wave vibration exposure duration with the levels of nerve and artery tissue injury, Aim 3 To evaluate by repeated measures the occurrence and recoverability of vibration-induced functional deficits in the innervation and blood supply of the rat-tail following 12 minute shock wave vibration per day for 1 day, 1 week and 10 weeks, and Aim 4 To evaluate the occurrence and recoverability of vibration-induced structural deficits in the innervation and blood supply of the rat-tail following 12 minute shock wave vibration per day for 1 day, 1 week and 10 weeks. Challenge to existing paradigm: The need for data on shock vibration is critical because the existing International Standard ISO 5349 does not take into account impulse vibration and high frequency components in risk calculation, and therefore, the Standard seriously underestimates the harm to workers. ISO 5349 attenuates high frequency contribution because of studies reporting that humans do not "feel" vibrations >1000 Hz. Expected outcomes: The proposed research will demonstrate that "what you can't feel can hurt you". The dose response data will aid development of evidenced-base guidelines for protecting workers and challenge manufacturers to eliminate offensive vibration. Our collaborator, Dr. Dong, at the NIOSH HELD research laboratory Morgantown, WV will test the efficacy of antivibration glove protection and develop new engineering methods to measure shock vibration in the workplace so that exposure can be monitored. Changing barriers to workplace protection: The results of the proposed research will advance the understanding of the dose response relationships of sinusoidal and shock wave vibration to tissue injury. These data will guide development of interventions that lower risk of hand arm vibration injury in the workplace.