Cavill G, Simpson E J, Mahajan R P
University Department of Anaesthesia, Queen's Medical Centre and City Hospital NHS Trust, Nottingham.
Br J Anaesth. 1998 Sep;81(3):317-21. doi: 10.1093/bja/81.3.317.
The transient hyperaemic response in the middle cerebral artery blood flow velocity on the release of brief compression of the ipsilateral common carotid artery has been validated as an indicator of cerebral autoregulation. We evaluated, in three stages, the effect of experimental factors such as duration of compression of the common carotid artery and magnitude of the decrease in blood flow velocity during common carotid artery compression on the transient hyperaemic response. In stage 1, 13 healthy volunteers underwent six transient hyperaemic response tests each; two tests each for either 3, 6 or 10 s duration of compression of the common carotid artery. In stage 2, 10 volunteers underwent four transient hyperaemic response tests each; two tests each for either 10 or 15 s duration of compression of the common carotid artery. In stage 3, data from the transient hyperaemic response tests using 10 s compression from the 23 volunteers who participated in stages 1 and 2 were analysed to evaluate the relationship between magnitude of decrease in blood flow velocity at the onset of compression and the transient hyperaemic response. The transient hyperaemic response ratio (blood flow velocity after the release of compression/baseline blood flow velocity) increased significantly when the duration of common carotid artery compression increased from 3 to 6 s, or from 6 to 10 s (stage 1); increase in the duration from 10 to 15 s did not have any significant effect (stage 2). The transient hyperaemic response ratio correlated significantly with the magnitude of decrease in blood flow velocity after compression, up to the values of the compression ratio (percent decrease in blood flow velocity at the onset of compression) of 40% but not more (stage 3). We conclude that experimental factors such as duration of common carotid artery compression and magnitude of the decrease in blood flow velocity during common carotid artery compression can significantly influence the transient hyperaemic response. These factors should be controlled if the transient hyperaemic response test is used for a comparison between repeated measurements. A compression time of 10 s and a compression ratio of 40% or more, allow maximum expression of the hyperaemic response in healthy volunteers.
同侧颈总动脉短暂受压解除后大脑中动脉血流速度的短暂充血反应已被确认为脑自动调节的一个指标。我们分三个阶段评估了实验因素的影响，如颈总动脉受压持续时间以及颈总动脉受压期间血流速度下降幅度对短暂充血反应的影响。在第一阶段，13名健康志愿者每人进行6次短暂充血反应测试；颈总动脉受压持续时间分别为3秒、6秒或10秒，每种持续时间各进行2次测试。在第二阶段，10名志愿者每人进行4次短暂充血反应测试；颈总动脉受压持续时间分别为10秒或15秒，每种持续时间各进行2次测试。在第三阶段，对参与第一阶段和第二阶段的23名志愿者进行的使用10秒受压时间的短暂充血反应测试数据进行分析，以评估受压开始时血流速度下降幅度与短暂充血反应之间的关系。当颈总动脉受压持续时间从3秒增加到6秒，或从6秒增加到10秒时，短暂充血反应比率（受压解除后的血流速度/基线血流速度）显著增加（第一阶段）；从10秒增加到15秒对其没有显著影响（第二阶段）。短暂充血反应比率与受压后血流速度下降幅度显著相关，直至受压比率（受压开始时血流速度下降百分比）达到40%，但超过40%则无显著相关性（第三阶段）。我们得出结论，颈总动脉受压持续时间和颈总动脉受压期间血流速度下降幅度等实验因素可显著影响短暂充血反应。如果使用短暂充血反应测试进行重复测量之间的比较，则应控制这些因素。10秒的受压时间和40%或更高的受压比率可使健康志愿者的充血反应达到最大程度的表达。
