心肺复苏（cardiopulmonary resuscitation，CPR）是心搏骤停时最常用的抢救方法。2010年CPR指南强调高质量胸外按压，建议除颤后继续按压2rain后再判断循环以减少按压中断时间。然而，临床中自主循环恢复（return of spontaneous circu...心肺复苏（cardiopulmonary resuscitation，CPR）是心搏骤停时最常用的抢救方法。2010年CPR指南强调高质量胸外按压，建议除颤后继续按压2rain后再判断循环以减少按压中断时间。然而，临床中自主循环恢复（return of spontaneous circulation，ROSC）多发生在按压过程中，此时持续按压不利于自主循环稳定。因此在CPR中识别ROSC十分重要。目前临床上可用于CPR中ROSC的预测和识别方法包括：触及脉搏搏动、波幅谱面积、呼气末二氧化碳分压、冠脉灌注压、中心静脉氧饱和度、胸外按压分数、局部脑氧饱和度、光学容积描记图、结膜氧张力、经胸阻抗容积描记术及超声心动图。本文对以上CPR过程中ROSC预测及识别方法做一综述。展开更多
目的脉搏血氧饱和度监测目前广泛应用于临床。近年来研究显示脉搏血氧波形（pulse oximetry plethysmographic wavefoiTn，POP）能实时反应患者循环状态改变。本研究将POP参数化，通过观察正常人群POP参数的分布，制定其正常参考值范围...目的脉搏血氧饱和度监测目前广泛应用于临床。近年来研究显示脉搏血氧波形（pulse oximetry plethysmographic wavefoiTn，POP）能实时反应患者循环状态改变。本研究将POP参数化，通过观察正常人群POP参数的分布，制定其正常参考值范围。方法多中心前瞻性描述性研究。以全国7个城市的健康成人1019人为研究对象，记录性别、年龄、身高、体质量，采集其室温平静状态下脉搏血氧数据，应用基于MATLAB2012a专用软件进行脉搏血氧波形参数及血流灌注指数提取，并制定脉搏血氧波形参数[脉搏血氧波形幅度参数（the amplitude of POP，Amp）、脉搏血氧波形曲线下面积参数（the area under the curve of POP，AUC）]正常参考值范围。结果正常成人脉搏血氧波形参数在男性和女性之间有明显差异。95％置信区间下正常人群Amp正常参考值为（104．8—2298．7）PVA；AUC正常参考值为（3265．8—6028．5）PVPG。男性Amp正常参考值为（129．4—2433．6）PVA；AUC正常参考值为（3319．0—5862．2）PVPG。女性Amp正常参考值为（89．5—2138．2）PVA；AUC正常参考值为（3163．9～5929．9）PVPG。结论脉搏血氧波形参数包括脉搏血氧波形幅度参数和脉搏血氧波形面积参数，在正常成人中有一定的参考范围。展开更多
Lung ultrosonograghy is increasingly used in the intensive care unit.It not only makes prompt management based upon reproducible data,but also generates fewer computed tomography(CT)examinations, therefore decreasing ...Lung ultrosonograghy is increasingly used in the intensive care unit.It not only makes prompt management based upon reproducible data,but also generates fewer computed tomography(CT)examinations, therefore decreasing irradiation,cost,delays,and movement to the patient.The aim of this article is to introduce the advantages of lung ultrosonography and the image features of the critically ill.展开更多
In the field of traffic flow studies, compulsive lane-changing refers to lane-changing （LC） behaviors due to traffic rules or bad road conditions, while free LC happens when drivers change lanes to drive on a faster...In the field of traffic flow studies, compulsive lane-changing refers to lane-changing （LC） behaviors due to traffic rules or bad road conditions, while free LC happens when drivers change lanes to drive on a faster or less crowded lane. LC studies based on differential equation models accurately reveal LC influence on traffic environment. This paper presents a second-order partial differential equation （PDE） model that simulates both compulsive LC behavior and free LC behavior, with lane-changing source terms in the continuity equation and a lane-changing viscosity term in the momentum equation. A specific form of this model focusing on a typical compulsive LC behavior, the ＇off-ramp problem＇, is derived. Numerical simulations are given in several cases, which are consistent with real traffic phenomenon.展开更多
In this paper, a new continuum traffic flow model is proposed, with a lane-changing source term in the continuity equation and a lane-changing viscosity term in the acceleration equation. Based on previous literature,...In this paper, a new continuum traffic flow model is proposed, with a lane-changing source term in the continuity equation and a lane-changing viscosity term in the acceleration equation. Based on previous literature, the source term addresses the impact of speed difference and density difference between adjacent lanes, which provides better precision for free lane-changing simulation; the viscosity term turns lane-changing behavior to a ＂force＂ that may influence speed distribution. Using a flux-splitting scheme for the model discretization, two cases are investigated numerically. The case under a homogeneous initial condition shows that the numerical results by our model agree well with the analytical ones; the case with a small initial disturbance shows that our model can simulate the evolution of perturbation, including propagation,dissipation, cluster effect and stop-and-go phenomenon.展开更多
文摘心肺复苏（cardiopulmonary resuscitation，CPR）是心搏骤停时最常用的抢救方法。2010年CPR指南强调高质量胸外按压，建议除颤后继续按压2rain后再判断循环以减少按压中断时间。然而，临床中自主循环恢复（return of spontaneous circulation，ROSC）多发生在按压过程中，此时持续按压不利于自主循环稳定。因此在CPR中识别ROSC十分重要。目前临床上可用于CPR中ROSC的预测和识别方法包括：触及脉搏搏动、波幅谱面积、呼气末二氧化碳分压、冠脉灌注压、中心静脉氧饱和度、胸外按压分数、局部脑氧饱和度、光学容积描记图、结膜氧张力、经胸阻抗容积描记术及超声心动图。本文对以上CPR过程中ROSC预测及识别方法做一综述。
文摘目的脉搏血氧饱和度监测目前广泛应用于临床。近年来研究显示脉搏血氧波形（pulse oximetry plethysmographic wavefoiTn，POP）能实时反应患者循环状态改变。本研究将POP参数化，通过观察正常人群POP参数的分布，制定其正常参考值范围。方法多中心前瞻性描述性研究。以全国7个城市的健康成人1019人为研究对象，记录性别、年龄、身高、体质量，采集其室温平静状态下脉搏血氧数据，应用基于MATLAB2012a专用软件进行脉搏血氧波形参数及血流灌注指数提取，并制定脉搏血氧波形参数[脉搏血氧波形幅度参数（the amplitude of POP，Amp）、脉搏血氧波形曲线下面积参数（the area under the curve of POP，AUC）]正常参考值范围。结果正常成人脉搏血氧波形参数在男性和女性之间有明显差异。95％置信区间下正常人群Amp正常参考值为（104．8—2298．7）PVA；AUC正常参考值为（3265．8—6028．5）PVPG。男性Amp正常参考值为（129．4—2433．6）PVA；AUC正常参考值为（3319．0—5862．2）PVPG。女性Amp正常参考值为（89．5—2138．2）PVA；AUC正常参考值为（3163．9～5929．9）PVPG。结论脉搏血氧波形参数包括脉搏血氧波形幅度参数和脉搏血氧波形面积参数，在正常成人中有一定的参考范围。
文摘Lung ultrosonograghy is increasingly used in the intensive care unit.It not only makes prompt management based upon reproducible data,but also generates fewer computed tomography(CT)examinations, therefore decreasing irradiation,cost,delays,and movement to the patient.The aim of this article is to introduce the advantages of lung ultrosonography and the image features of the critically ill.
基金supported by the National Natural Science Foundation of China(Grant Nos.11002035 and 11372147)
文摘In the field of traffic flow studies, compulsive lane-changing refers to lane-changing （LC） behaviors due to traffic rules or bad road conditions, while free LC happens when drivers change lanes to drive on a faster or less crowded lane. LC studies based on differential equation models accurately reveal LC influence on traffic environment. This paper presents a second-order partial differential equation （PDE） model that simulates both compulsive LC behavior and free LC behavior, with lane-changing source terms in the continuity equation and a lane-changing viscosity term in the momentum equation. A specific form of this model focusing on a typical compulsive LC behavior, the ＇off-ramp problem＇, is derived. Numerical simulations are given in several cases, which are consistent with real traffic phenomenon.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11002035 and 11372147)Hui-Chun Chin and Tsung-Dao Lee Chinese Undergraduate Research Endowment(Grant No.CURE 14024)
文摘In this paper, a new continuum traffic flow model is proposed, with a lane-changing source term in the continuity equation and a lane-changing viscosity term in the acceleration equation. Based on previous literature, the source term addresses the impact of speed difference and density difference between adjacent lanes, which provides better precision for free lane-changing simulation; the viscosity term turns lane-changing behavior to a ＂force＂ that may influence speed distribution. Using a flux-splitting scheme for the model discretization, two cases are investigated numerically. The case under a homogeneous initial condition shows that the numerical results by our model agree well with the analytical ones; the case with a small initial disturbance shows that our model can simulate the evolution of perturbation, including propagation,dissipation, cluster effect and stop-and-go phenomenon.
