The study of prevention of venous air embolism -Concerning with dural sinus pressure

当阴道压力在临床案例和动物实验中被研究为预防有效的空气Embolism，它展示了这一点，不仅仅是重力，但也是颈部的抗词和旋转，操作期间的各种操纵，Durg-or Bleeding-induced hypotension等，它影响了它的发展，但在另一方面，它被认为是指颈部、PEEP、颈部和基本压缩、外部流体管理和药物诱导的超负荷对预防是有用的。在它们中间，诱导性高血压和连续性颈部压缩是预期的临床应用，和晶体循环（H2清除方法的rCBF，方形波电磁流量的垂直血液流动），晶体功能（cortical EEG）和血液屏障的功能（BBB）应该是这些进一步评估的动物实验。（1）诱导性高血压：在平均血压增加40%时，血液压力增加了45%时，研究过的较高位置与RCBF和VBF增加了8%和7%的40%-诱导高血压时，当自动化在80%时被打破时，通过运行表的运行被认为受到40%的影响时，延迟被80%的影响。BBB缺失没有被40%注意到-诱导性高血压，但明显被80%注意到。（2）颈部压缩：血液压力测量的袖口已经滚动到皮肤上，其内部压力调整到15毫米汞，30毫米汞用于控制，rCBF减少到22，3%为15毫米汞的内部压力，进一步减少到30毫米汞的45%。特定功能的重力倾向和BBB的功能被颈部压缩注意到，这些结果建议这样做。40%-诱导高血压对防止空气排斥的贡献，并且没有问题对临床应用，而颈部压缩对临床应用有许多问题。

When dural sinus pressure was studied in the clinical cases and animal experiments in order to prevent venous air embolism,it was shown that,not only gravity,but also anteflexion and rotation of the neck,various manipulation during operation,durg-or bleeding-induced hypotension,etc.,were influenced for its development.On the other hand, it was considered that retroflexion of the neck,PEEP,neck and abdominal compression,extraneous fluid administration and drug induced hypertension are useful for its prevention. Among them,induced hypertension and continuous neck compression were expected for clinical application,and cerebral circulation(rCBF by H2 clearance method, vertebral blood flow by square wave electromagnetic flowmetry),cerebral function (cortical EEG)and function of blood brain barrier (BBB)due to these were further evaluated by animal experiments. (1)induced hypertension:The various changes at the increase of 40% of mean blood pressure at 45゜upright position were studied comparing with those of 80% rCBF and VBF increased to 8% and 7% by 40%-induced hypertension, while the autoregulation were broken down by 80% In cEEG, slow wave recognized by elevation of the operating table was considerably impproved by 40%,while rather aggravate by 80%. BBB dysruption was not noted by 40%-induced hypertension,while noted remarkably by 80%. (2)Neck compression:The cuff for the blood pressure mesurment was rolled so as to adhere to the skin,and its internal pressure was adjusted to 15mmHg,and 30mmHg was employed for control.rCBF decreased to 22,3% by 15mmHg of intracuff pressure,and more decreased to 45% by 30mmHg. The aggravating tendency of cerebral function and function of BBB was noted by neck compression.These results suggest that approx. 40%-induced hypertension contribute to the prevention of air embolism, and no problem for the clinical application,while neck compression has many problem for the clinical application.