Whitehouse H E, Czosnyka M, Pickard J D
Academic Neurosurgery Unit, Addenbrooke's Hospital, Cambridge, UK.
Childs Nerv Syst. 1994 Apr;10(3):158-61. doi: 10.1007/BF00301082.
Studies of long-term shunt performance in vivo demonstrate that some 81% fail within 12 years. Such failure is multifactorial in origin: the patient, the surgical technique and the shunt may all prove fallible. Recent studies have shown that there is considerable variability of the performance characteristics of individual shunts when tested for short time periods in relatively simple rigs, and that they do not always behave according to the manufacturers' specifications. We have developed a computerized shunt rig for the long-term evaluation of a valve's performance in vitro using both pressure-flow studies (where flow through the shunt is evaluated for controlled differential pressure across the shunt) and flow-pressure studies (where the differential pressure across the shunt is evaluated for controlled flow rates through the shunt). This rig consists of a pressure transducer, electronic balance, computer-controlled infusion pump and blood pressure systems calibrator that stimulates different wave form patterns. An IBM PC controls all the devices and evaluates the performances characteristics according to various test protocols. Our initial observations with this rig confirm that progressive changes in shunt function occur over long periods of time (weeks).
对体内长期分流器性能的研究表明，约81%的分流器在12年内失效。这种失效的原因是多方面的：患者、手术技术和分流器都可能出问题。最近的研究表明，当在相对简单的装置中进行短时间测试时，各个分流器的性能特征存在相当大的差异，而且它们并不总是按照制造商的规格运行。我们开发了一种计算机化的分流器装置，用于在体外长期评估瓣膜的性能，采用压力-流量研究（评估通过分流器的流量以控制分流器两端的压差）和流量-压力研究（评估分流器两端的压差以控制通过分流器的流速）。该装置由压力传感器、电子天平、计算机控制的输液泵和能模拟不同波形模式的血压系统校准器组成。一台IBM个人电脑控制所有设备，并根据各种测试协议评估性能特征。我们使用该装置的初步观察结果证实，分流功能在很长一段时间（数周）内会逐渐发生变化。
