A new approach to evaluate the anesthetic depth by evoked potential with sequential double stimulation.

我们观察到一种新的现象，即由双重感觉刺激引起的两个诱发电位的比率随着麻醉深度的变化而动态变化。用七氟醚麻醉雄性SD大鼠颅骨上的一套螺丝电极记录体感诱发电位。对上肢连续两次电刺激，计算第一反应(R1)和第二反应(R2)的幅值比(R2/R1)。当刺激间隔约为300毫秒时，R2/R1随麻醉深度的变化而动态减小。另一方面，如果刺激间间隔大于300毫秒，则下降较小。提示R2/R1可作为评价麻醉深度的新指标。

We observed a novel phenomenon that a ratio of two evoked potentials elicited by double sensory stimulation dynamically changes in response to the depth of anesthesia. Somatosensory evoked potential was recorded via a set of screw electrode on the skull in a male SD rat under the sevoflurane anesthesia. Two consecutive electrical stimulations were applied to the upper limb, and an amplitude ratio of the first response (R1) and second response (R2) were calculated (R2/R1). When the interstimulus interval is around 300 msec, R2/R1 dynamically decrease in response to the depth of anesthesia. On the other hand, if the interstimulus interval is longer than 300 msec, the decrease is smaller. These results suggest that the R2/R1 may be a novel indicator for evaluating the anesthetic depth.