Effects of Creep and Cyclic Loading on the Mechanical Properties and Failure of Human Achilles Tendons

The Achilles tendon is one of the most frequently injured tendons in humans, and yet the mechanisms underlying its injury are not well understood. This study examines the ex vivo mechanical behavior of excised human Achilles tendons to elucidate the relationships between mechanical loading and Achilles tendon injury. Eighteen tendons underwent creep testing at constant stresses from 35 to 75 MPa. Another 25 tendons underwent sinusoidal cyclic loading at 1 Hz between a minimum stress of 10 MPa and maximum stresses of 30–80 MPa. For the creep specimens, there was no significant relationship between applied stress and time to failure, but time to failure decreased exponentially with increasing initial strain (strain when target stress is first reached) and decreasing failure strain. For the cyclically loaded specimens, secant modulus decreased and cyclic energy dissipation increased over time. Time and cycles to failure decreased exponentially with increasing applied stress, increasing initial strain (peak strain from first loading cycle), and decreasing failure strain. For both creep and cyclic loading, initial strain was the best predictor of time or cycles to failure, supporting the hypothesis that strain is the primary mechanical parameter governing tendon damage accumulation and injury. The cyclically loaded specimens failed faster than would be expected if only time-dependent damage occurred, suggesting that repetitive loading also contributes to Achilles tendon injuries. © 2003 Biomedical Engineering Society. PAC2003: 8719Rr     

构建急性肾损伤患者连续性肾脏替代治疗剂量达成模型

按照课题研究型品管圈活动步骤,针对急性肾损伤患者连续性肾脏替代治疗处方治疗剂量与实际治疗剂量存在较大差异的现状,对剂量管理现状、攻坚点进行分析与发掘,针对性拟定对策并实施,包括建立集束化血管通路管理策略,制定最优滤器管路使用技术方案,构建全流程CRRT智能管理平台。活动开展后,CRRT治疗剂量达成率由78.5%上升至93.5%,治疗时间达成率、平均CRRT治疗日、28 d存活率、出院时透析依赖率等均有不同程度改善,活动效果显著。     

降低重型胸部损伤患者肠内营养喂养不耐受发生率

目的降低重型胸部损伤患者肠内营养喂养不耐受发生率。方法成立品管圈小组,针对腹胀、反流或呕吐、腹泻三大改善重点展开原因分析,从多样化培训、6S管理、风险评估等方面进行针对性改进。结果重型胸部损伤患者肠内营养喂养不耐受发生率由63.01%降低至20.55%。结论肠内营养喂养不耐受是重症患者营养实施过程中的常见问题,通过品管圈活动,建立了科学的评估体系和规范的干预措施,改善了重型胸部损伤患者肠内营养喂养不耐受情况,确保了患者安全。     

2014—2019年江西省伤害死亡情况及疾病负担分析

目的 了解江西省居民伤害死亡流行情况及其疾病负担,为科学制定本省伤害防制策略和措施提供依据。方法 利用中国死因登记报告信息系统2014—2019年江西死因监测数据,应用Excel 2007和SPSS 17.0软件进行数据整理和分析。采用死亡数、粗死亡率、标化死亡率、构成比、潜在减寿年数（PYLL）、减寿率（PYLLR）和平均潜在减寿年数(AYLL)等指标进行统计学描述,趋势变化采用年度变化百分比（APC）进行分析。结果 2014—2019年江西报告伤害死亡25 638人,年均粗死亡率为 50.81/10万,年均标化死亡率为 49.55/10万。男性死亡率高于女性、城市死亡率高于农村。伤害死亡前5位死因分别为道路交通事故、跌落、溺水、自杀和中毒。溺水、交通事故、跌落分别是0～14岁、15～44和45～64岁、≥65岁的首位伤害死因。2014—2019年江西省前5位伤害死因中,跌落粗死亡率呈上升趋势（APC = 8.22%）,中毒粗死亡率均呈下降趋势。2014—2019年伤害PYLL为692 196.73人年,PYLLR为14.24‰,AYLL 为 33.77年。PYLL及PYLLR 交通事故最高,AYLL最高的为溺水。15～44岁年龄组PYLL最高。结论 江西省伤害死亡负担较重,应根据不同人群的伤害死亡特征制定相应的防控策略和措施。     

产后妇女盆底肌损伤发生情况调查研究

目的 探讨产后妇女盆底肌功能情况并分析造成妇女产后盆底肌损伤的相关因素,为预防妇女因生产造成盆底肌损伤提供科学依据。方法 以2019年1月至2020年11月在湖南省长沙市和株洲市各1家医院产科进行6~8周产后复查的产妇为研究对象进行资料收集及盆底肌力测定,采用描述流行病学分析方法进行盆底肌力异常情况分析,并采用单、多因素分析方法对产后妇女盆底肌异常影响因素进行分析。结果 本研究共对1 628名产妇进行调查,年龄22~38岁,平均（29.68±5.36）岁;孕次1~5次,平均孕次（2.43±1.16）次;产次1~5次,以1~2次为主,占72.4%。检出1 142例产后6~8周产妇为盆底肌力异常,异常率为70.2%。年龄30~38岁（OR=3.766）、产次≥3次（OR=2.633）、阴道分娩（OR=7.478）、孕期增重过多（OR=1.597 ）及胎儿出生体重≥4 kg（OR=5.078）的产后妇女盆底肌力异常的风险较高。结论 湖南省产后妇女盆底肌力异常率较高,年龄、产次、分娩方式、孕期增重及胎儿体质量是造成产妇产后发生盆底肌损伤的重要原因,应采取相应措施,降低产后妇女发生盆底肌损伤风险。     

伤病比在医院维权中的运用

为了保证民法的公平原则,避免医疗纠纷赔偿案件审理中忽视患者本身病情所致的不良后果的情况,对损伤与疾病对患者预后的影响进行了研究.介绍了伤病比的来源,论述了伤病比在医疗纠纷处理中的适用 范围,伤病比的级别与医院承担的赔偿额度.指出应增强伤病比意识,促进医与法的完美结合.     

睾酮对雄性家兔血管损伤后内皮功能及内膜增生的影响

目的探讨雄激素睾酮对雄性家兔腹主动脉球囊损伤后内皮功能及内膜增生的影响.方法选择健康雄性新西兰白兔24只随机分成三组假去势对照组、低睾酮血症组(去势)及睾酮替代组(去势1周后加用长效十一酸睾酮单次肌注,14mg/kg),每组8只.去势10天后对所有动物行腹主动脉球囊损伤术.损伤后2周采血测血浆睾酮、血脂、一氧化氮(NO)、超氧化物歧化酶(SOD)及丙二醛(MDA)水平,并截取腹主动脉进行图像分析.结果低睾酮血症组的新生内膜面积明显高于假去势对照组和睾酮替代组(P＜0.01),且血浆总胆固醇、甘油三酯、低密度脂蛋白及MDA显著上升,NO和SOD水平明显下降,(P＜0.01或0.05).治疗组和对照组比较各数据无差异.结论生理水平的睾酮(内源或外源补充)抑制雄性家兔动脉损伤后的内膜增生,并保护内皮功能.     

An inverted ankle joint orientation at foot strike could incite ankle inversion sprain: Comparison between injury and non-injured cutting motions of a tennis player

Ankle sprain is very common in sports. Research on its prevention is as important as on its treatment as recommended in the 2016 consensus statement of the International Ankle Consortium. Successful prevention depends on the understanding of its mechanism, which has been presented with quantities in some recent case reports. Inciting event was suggested to be an inverted ankle joint at foot strike, however, is still lacking evidence from comparison with non-injury trials. This study investigated the ankle joint orientation at foot strike in successful non-injury cases and compared them with a previously analysed ankle sprain injury case. Two injury-free cutting motions with similar movement approach to a previously analysed ankle sprain injury performed by the same athlete were collected from an online search and were trimmed from 0.05 s before until 0.30 s after the foot strike. The video sequences were then processed by video editing software and then analysed by a model-based image-matching motion analysis technique. Ankle joint orientation at foot strike and the profiles were presented in inversion, plantarflexion and rotation planes, for both the previously analysed injury case and the two non-injury cases. The ankle joint orientation at foot strike was 0–1 degree inverted and 10–21° dorsiflexed in the two non-injury cases, compared to 14° inverted and 16° plantarflexed in the previously analysed injury case. From the case comparison, it can be observed that an inverted ankle joint orientation at foot strike in an inciting event of ankle inversion sprain.     

Pulmonary contusions in patients with rib fractures: The need to better classify a common injury

BackgroundPulmonary contusions are common injuries. Computed tomography reveals vast contused lung volume spectrum, yet pulmonary contusions are defined dichotomously (unilateral vs bilateral). We assessed whether there is stepwise increased risk of pulmonary complications among patients without, with unilateral, and with bilateral pulmonary contusion.MethodsWe identified adults admitted with rib fractures using the largest US inpatient database. After propensity-score-matching patients without vs with unilateral vs bilateral pulmonary contusions and adjusting for residual confounders, we compared risk for pneumonia, ventilator-associated pneumonia (VAP), respiratory failure, intubation, and mortality.ResultsAmong 148,140 encounters of adults with multiple rib fractures, 19% had concomitant pulmonary contusions. Matched patients with pulmonary contusions had increased risk of pneumonia 19% [95%CI:16–33%], respiratory failure 40% [95%CI: 31–50%], and intubation 46% [95%CI: 33–61%]. Delineation showed bilateral contusions, not unilateral contusions, attributed to increased risk of complications.ConclusionsThere is likely a correlation between contused lung volume and risk of pulmonary complications; dichotomously classifying pulmonary contusions is insufficient. Better understanding this correlation requires establishing the clinically significant contusion volume and a correspondingly refined classification system.