Understanding Vibration Injury

描述（由申请人提供）：拟议研究的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相一致，该目标旨在减少美国建筑工人中与工作相关的肌肉骨骼疾病的发病率和严重程度。根据美国劳工统计局和公布的流行病学数据，估计有150万工人在建筑、制造业、农林和渔业中使用电动工具。和采矿部门，目前暴露于手臂振动水平，使他们在工作10年后面临患手臂振动综合征（HAVS）的风险，患病率为10-50%。HAVS的主要神经和动脉病变是使人衰弱的麻木和手指血流量减少。方法：在研究中将人体暴露在破坏性的振动中是不道德的，因此具有与人类手指结构和功能相似的神经和动脉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激波分量。评估了导致HAVS的振动频率（Hz）、加速度（m/s2 r.m.s）、振幅（mm）和持续时间（振动/天和振动天数）的危险因素。我们新开发的脉冲冲击波模型可从铆接锤产生0.5 Hz至超过21 kHz的振动分量，可产生许多冲击工具的冲击波振动特性。90多年前人们就认识到冲击波振动损伤，但一直被忽视。这一知识差距必须得到解决，因为严重的HAVS可能在2.5个月内发作，而非冲击性电动工具的开发则需要数年时间。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导频率在30-250 Hz范围内，而大多数HAVS都归因于此。人们忽略了一个事实，即非冲击性工具会产生冲击波，尽管频率较低。冲击性工具，如铆接锤、削片机、切石机、冲击钻和破路机，在每个工作周期都会产生冲击波脉冲。本研究拟对大鼠尾部振动的频率、加速度、振幅和持续时间进行定量研究，以探讨振动频率、加速度、振幅和持续时间与皮肤、动脉和骨骼肌神经支配结构损伤的关系，以及与感觉丧失和肌肉无力相关的功能缺陷（神经传导速度、von Frey触觉感知、热敏性、冷浸激发再升温和血流恢复）。拟议的研究有四个目标：目的1研究冲击波振动持续时间、频率、加速度和振幅对诱导大鼠尾正弦振动模型持续血管收缩的剂量反应。目的2明确冲击波振动暴露时间与神经和动脉组织损伤程度的剂量反应关系。目标3评估重复措施vibration-induced功能的存在和可恢复性赤字神经支配和血液供给的尖尾后12分钟冲击波振动每天1天,1周和10周,和目标4评估vibration-induced结构性赤字的发生和可恢复性的神经支配和血液供给尖尾后12分钟冲击波振动每天1天,1周和10周。对现有模式的挑战：对冲击振动数据的需求是至关重要的，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降低了高频的贡献，因为研究报告说，人类不会“感觉到”1000赫兹以下的振动。预期结果：拟议的研究将证明“你感觉不到的东西会伤害到你”。剂量反应数据将有助于制定保护工人的循证指导方针，并促使制造商消除有害振动。我们的合作者，东博士，在NIOSH HELD研究实验室摩根敦，WV将测试防振手套保护的功效，并开发新的工程方法来测量工作场所的冲击振动，以便监测暴露。改变工作场所防护屏障：拟议研究的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。这些数据将指导开发干预措施，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.