大骨瓣开颅减压颞肌贴敷治疗大面积脑梗死

目的探讨标准大骨瓣开颅减压治疗大面积脑梗死的手术适应证、手术方法及影响预后的因素。方法回顾分析了1997年3月至2008年4月收治的36例因大面积脑梗死而行标准大骨瓣开颅减压治疗的患者的疗效,以及GOS评分评定其临床效果。脑梗死发病距手术时间平均为42h(20h～4d)。结果所有患者均经随访,术后死亡10例(27.78%),其中年龄大于55岁者23例,死亡8例(34.78%);年龄小于55岁者13例,死亡2例(15.38%)。以GOS评价治疗效果,出院时死亡11例(30.56%),植物生存6例(16.67%),重残8例(22.22%),中残7例(19.44%),良好4例(11.11%)。术后6个月死亡11例(30.56%),植物生存5例(13.89%),重残5例(13.89%),中残8例(22.22%),良好7例(19.44%)。结论标准大骨瓣开颅减压能够极大提高大面积脑梗死患者的生存率及生存质量,是传统保守治疗失败后的一种极为有效疗法,其中手术技巧及手术时机的选择非常重要,年龄大于55岁及快速恶化者疗效差。     

微孔塑料连续挤出成型快速降压口模的数值模拟

利用Polyflow有限元软件对聚苯乙烯(PS)/CO2均相体系在连续挤出成型圆形快速降压口模中的流动进行数值模拟,考察快速降压口模入口角、长径比及口模温度对PS微孔塑料熔体沿轴线方向的压力降速率和剪切速率的影响。结果表明,当入口角大于30°时,改变入口角对压力降速率和剪切速率无明显影响,即对微孔塑料的气泡成核影响微小,但当入口角为0°时,与其它各入口角相比,其熔体压力降速率最大,气泡成核时间最早;在毛细管段口模直径不变的情况下,改变其长径比对熔体气泡成核亦无明显影响,但压力降随口模长度缩短而变小;口模温度对剪切速率影响不大,但降低口模温度,压力降速率明显提高,从而有利于微孔塑料的气泡成核。     

去骨瓣减压术后硬膜下积液的治疗

目的探讨去骨瓣减压术后硬膜下积液的治疗方法。方法对2002年1月至2010年1月56例去骨瓣减压术后硬膜下积液患者的临床资料进行回顾性分析。结果 56例中18例硬膜下积液经保守治疗痊愈。38例患者有明显的占位效应而采用手术治疗均治愈。结论穿刺引流及积液-腹腔分流术为去骨瓣减压术后硬膜下积液治疗的有效手段。     

Experimental Studies on Characteristics of Pressure Attenuation and Recovery to Saturation for Decompressive Disturbances in Low Pressurized Water

Slightly pressurized water (P _sat = 1.2–6.0 bar) was flashed into steam void by step decompression to atmospheric pressure, using a shock tube type device with vertical test section, made of stainless steel pipe about 2 m long, with an inner diameter of 40 mm. The transient pressure depression below saturation and the time constant of pressure recovery to the saturation were measured, based on the observed transient pressure response signals. The transient pressure curve could be approximated by the expression P(t) = P _min +(P _sat ?P _min )(1?e ^?t/τ) for the period immediately following step decompression. This time constant τ represents the effective relaxation time of thermodynamic nonequilibrium.

Defining the term decompression ratio ε as the ratio of the excess transient depression below saturation pressure to the difference between saturation and atmospheric pressure, i.e., ε=(P _sat ?P _min )/(P _sat ?P _fin ), the dependence of ε on the vertical position along the test column z and P _sat was found to follow approximately the empirical formula ε=exp[?β′{(P _sat /P _fin )?1}(z+z ⁰ )], where β was evaluated to be 0.43m^?1. Correspondingly, the attenuation constant β=(?1/ε)·dε/dz=β′{(P _sat /P _fin )?1}. The time constant τ was found to range between 10–300 msec, with a tendency to increase with decreasing saturation pressure determined by the measured water temperature. The value of τ showed little dependence on the position of observation along the test section. The expression 1/τ=βV (V being the propagation velocity of pressure waves) indicates a hyperbolic relation between τ and P _sat . This relation roughly agreed with experimental data.