钙预适应对膨胀离体大鼠心室所致心律失常的影响

为了证实钙预适应对膨胀离体大鼠心室所诱发的心律失常具有抑制作用 ,采用Langendorff方法灌流离体大鼠心脏。用正常灌流液灌流平衡后 ,离体心被随机分为 4组 :牵张对照组 ,钙预适应组 ,钙预适应 +维拉帕米组和钙预适应 +格列本脲组。维拉帕米和格列本脲在灌流液中的浓度分别为 1μmol/L和 10 μmol/L ,对钙预适应进行干预后及时用正常灌流液将他们从离体心洗脱。将可充灌液体的乳胶球囊通过左房及二尖瓣置于左室 ,通过向乳胶球囊注射液体对左室进行膨胀 ,记录膨胀前和膨胀过程中左室心电图和左室压力、冠脉流量和心率 ,观察心电图ST段和T波的变化 ,并计算对照组和各实验组由膨胀诱发心律失常的发生率和持续时间。结果 :通过乳胶球囊膨胀左室 ,使左室舒张末压增加相同的情况下 ,对照组心律失常总发生率达 10 0 % ,持续时间为 2 .5 6± 0 .4 6s ;钙预适应组较对照组心律失常总发生率明显降低 (40 % ) ,持续时间缩短到 1.6 7± 0 .6 1s(P均 <0 .0 5 ) ;用维拉帕米对钙预适应进行干预后 ,心律失常总发生率较钙预适应组增高 (90 % ) ,持续时间延长 (2 .5 0± 0 .4 6s) ;钙预适应 +格列本脲组心律失常发生情况和钙预适应组相似。各组离体心在膨胀前后冠脉流量和心率、心电图ST段和T波均未见明显变化。结论 :?     

Measuring and improving cardiopulmonary resuscitation quality inside the emergency department

Aim of studyTo evaluate CPR quality during cardiac resuscitation attempts in an urban emergency department (ED) and determine the influence of the combination of scenario-based training, real-time audiovisual feedback (RTAVF), and post-event debriefing on CPR quality.MethodsCPR quality was recorded using an R Series monitor-defibrillator (ZOLL Medical) during the treatment of adult cardiac arrest patients. Phase 1 (P1; 11/01/2010-11/15/2012) was an observation period of CPR quality. Phase 2 (P2; 11/15/2012-11/08/2013) was after a 60-min psychomotor skills CPR training and included RTAVF and post-event debriefing.ResultsA total of 52 cardiac arrest patients were treated in P1 (median age 56 yrs, 63.5% male) and 49 in P2 (age 60 yrs, 83.7% male). Chest compression (CC) depth increased from 46.7 ± 3.8 mm in P1 to 61.6 ± 2.8 mm in P2 (p < 0.001), with the percentage of CC ≥ 51 mm increasing from 30.6% in P1 to 87.4% in P2 (p < 0.001). CC release velocity increased from 314 ± 25 mm/s in P1 to 442 ± 20 mm/s in P2 (p < 0.001). No significant differences were identified in CC fraction (84.3% P1 vs. 88.4% P2, p = 0.1), CC rate (125 ± 3 cpm P1 vs. 125 ± 3 cpm P2, p = 0.7), or pre-shock pause (9.7 s P1 vs. 5.9 s P2, p = 0.5), though CC fraction and pre-shock pause were within guideline recommendations.ConclusionImplementation of the bundle of scenario-based training, real-time audiovisual CPR feedback, and post-event debriefing was associated with improved CPR quality and compliance with CPR guidelines in this urban teaching emergency department.     

植入式闭环芯片系统对清醒兔心率的调控作用

目的:通过电刺激迷走神经观察植入式闭环芯片系统对清醒兔心率的调控作用?方法:将12只心率正常的新西兰兔随机分2组:对照组?迷走神经电刺激(vagus nerve stimulation,VNS)组?VNS组兔体内植入自主研发的闭环芯片1周,随机电刺激右侧迷走神经1 h,恢复1 h;对照组体内植入无刺激的芯片?MD2000WL软件记录实时心电图(electrocardiogram,ECG),芯片根据ECG计算心率?结果:植入式闭环芯片可在清醒兔体内工作?芯片可以成功记录完整心电图?VNS组调控期间心率明显低于调控前的基础心率[(265.2 ± 15.2)次/min vs.(289.5 ± 15.7) 次/min,P < 0.05]?VNS组调控期间心率和对照组相比较,VNS组的心率明显降低[(-24.3 ± 3.6) 次/min vs.(-4.6 ± 5.1)次/min,P < 0.05]?结论:植入式闭环芯片系统可以长期调控清醒兔的心率?     

Masthead,Volume 73, Issue 1

This review provides a summary statement of recommended implementations of arterial spin labeling (ASL) for clinical applications. It is a consensus of the ISMRM Perfusion Study Group and the European ASL in Dementia consortium, both of whom met to reach this consensus in October 2012 in Amsterdam. Although ASL continues to undergo rapid technical development, we believe that current ASL methods are robust and ready to provide useful clinical information, and that a consensus statement on recommended implementations will help the clinical community to adopt a standardized approach. In this review, we describe the major considerations and trade‐offs in implementing an ASL protocol and provide specific recommendations for a standard approach. Our conclusion is that as an optimal default implementation, we recommend pseudo‐continuous labeling, background suppression, a segmented three‐dimensional readout without vascular crushing gradients, and calculation and presentation of both label/control difference images and cerebral blood flow in absolute units using a simplified model. Magn Reson Med 73:102–116, 2015. © 2014 Wiley Periodicals, Inc.     

Real-time modulation of visual feedback on human full-body movements in a virtual mirror: development and proof-of-concept

Background

Virtual reality (VR) provides interactive multimodal sensory stimuli and biofeedback, and can be a powerful tool for physical and cognitive rehabilitation. However, existing systems have generally not implemented realistic full-body avatars and/or a scaling of visual movement feedback. We developed a “virtual mirror” that displays a realistic full-body avatar that responds to full-body movements in all movement planes in real-time, and that allows for the scaling of visual feedback on movements in real-time. The primary objective of this proof-of-concept study was to assess the ability of healthy subjects to detect scaled feedback on trunk flexion movements.

Methods

The “virtual mirror” was developed by integrating motion capture, virtual reality and projection systems. A protocol was developed to provide both augmented and reduced feedback on trunk flexion movements while sitting and standing. The task required reliance on both visual and proprioceptive feedback. The ability to detect scaled feedback was assessed in healthy subjects (n = 10) using a two-alternative forced choice paradigm. Additionally, immersion in the VR environment and task adherence (flexion angles, velocity, and fluency) were assessed.

Results

The ability to detect scaled feedback could be modelled using a sigmoid curve with a high goodness of fit (R² range 89-98%). The point of subjective equivalence was not significantly different from 0 (i.e. not shifted), indicating an unbiased perception. The just noticeable difference was 0.035 ± 0.007, indicating that subjects were able to discriminate different scaling levels consistently. VR immersion was reported to be good, despite some perceived delays between movements and VR projections. Movement kinematic analysis confirmed task adherence.

Conclusions

The new “virtual mirror” extends existing VR systems for motor and pain rehabilitation by enabling the use of realistic full-body avatars and scaled feedback. Proof-of-concept was demonstrated for the assessment of body perception during active movement in healthy controls. The next step will be to apply this system to assessment of body perception disturbances in patients with chronic pain.     

Control strategies for active lower extremity prosthetics and orthotics: a review

Technological advancements have led to the development of numerous wearable robotic devices for the physical assistance and restoration of human locomotion. While many challenges remain with respect to the mechanical design of such devices, it is at least equally challenging and important to develop strategies to control them in concert with the intentions of the user.This work reviews the state-of-the-art techniques for controlling portable active lower limb prosthetic and orthotic (P/O) devices in the context of locomotive activities of daily living (ADL), and considers how these can be interfaced with the user’s sensory-motor control system. This review underscores the practical challenges and opportunities associated with P/O control, which can be used to accelerate future developments in this field. Furthermore, this work provides a classification scheme for the comparison of the various control strategies.As a novel contribution, a general framework for the control of portable gait-assistance devices is proposed. This framework accounts for the physical and informatic interactions between the controller, the user, the environment, and the mechanical device itself. Such a treatment of P/Os – not as independent devices, but as actors within an ecosystem – is suggested to be necessary to structure the next generation of intelligent and multifunctional controllers.Each element of the proposed framework is discussed with respect to the role that it plays in the assistance of locomotion, along with how its states can be sensed as inputs to the controller. The reviewed controllers are shown to fit within different levels of a hierarchical scheme, which loosely resembles the structure and functionality of the nominal human central nervous system (CNS). Active and passive safety mechanisms are considered to be central aspects underlying all of P/O design and control, and are shown to be critical for regulatory approval of such devices for real-world use.The works discussed herein provide evidence that, while we are getting ever closer, significant challenges still exist for the development of controllers for portable powered P/O devices that can seamlessly integrate with the user’s neuromusculoskeletal system and are practical for use in locomotive ADL.     

录像反馈法在医学教学中的应用

目的：探讨录像反馈法在医学教学中的积极应用的方法及体会。方法：收集某高校42名2011级全日制本科临床医学生作为研究对象,将所有研究对象按照近期的考核成绩从高到低排序,将成绩相邻两名受试者配成1对,共21对,然后将每对中的2个人随机分配到试验组和对照组。其中,对照组运用传统纸笔记录方式,试验组采用录像反馈式教学法,利用VCD及教学讲解心肺复苏内容,教学2周,每周2节课时,2周后,根据两组受试者的技能操作考核成绩及对教育方法的满意度和有效率来判断两组的教学差异。结果：对照组在考核成绩方面低于试验组,在学习兴趣、满意度、认真程度的有效率方面,对照组均低于试验组,差异具有统计学意义（P<0.05）。结论：录像反馈教学在医学教学中对学生的学习兴趣、满意度、认真程度以及学生的考核成绩均有积极作用,值得在医学教学中推广应用。