Application of Electroretinogram to Anesthetic Depth Monitor

本研究表明，吸入麻醉药和缺氧对兔ERG的影响不同，ERG可作为术中麻醉深度和脑缺氧的监测手段应用于临床。然后，我们制作了术中ERG监测装置。该装置由个人计算机、光刺激器、隐形眼镜电极和放大器组成。光刺激器和电极通过光纤连接。利用该装置，我们进行了以下研究。本文观察了12例手术病人麻醉时安氟醚对视网膜电图（ERG）的影响。在0%、0.8%、1.7%呼气末安氟醚浓度下进行记录。随着安氟醚浓度的增加，a波、b波和ops的潜伏期有统计学意义的增加。随着安氟醚浓度的增加，a波的振幅降低，但b波的振幅没有改变。其中OP的潜伏期是反映麻醉深度最敏感的指标。在研究过程中发现了一些问题。其中一个问题是手术室中许多电气设备的电气干扰。另一个问题是电极在操作期间的移位。通过光纤的光量可能不足。将该技术应用于临床，还有许多问题需要解决。但这可能是未来麻醉深度和脑缺氧监测的一种可能。

Our study using rabbits showed that volatile anesthetics and hypoxia alter the rabbit ERG inthe different manner and it seemed to be possible to apply ERG to clinical practise as an intraoperative monitoring of anesthetic depth and brain hypoxia. Then, we have made intraoperative erg monitoring device. This device is composed of personal computer, hpotostimulator, electrode of contactlens form and amplifier. Photostimulator and electrode are linked with fiberoptics. Using this device, we made the followoing study. The effects of enflurane on ERG was studied in 12 patients undergoingsurgical procedures. Recordings were made at 0%, 0.8%, 1.7% end-tidal enflurane concentration. There were statistically significant increases in the latencies of the a-waves, b-waves, ops with increasing concentrations of enflurane. The amplitudes of the a-waves were reduced with increasing concentrations of enflurane, but the amplitudes of the b-waves did not chage. The latencies of OP were thougt to be the most sensitive indicator of the anesthetic depth among these parameters. Some problems were found during this study. One of these problems is electrical interference of many electric device s in the operating room. Another problem is a shift of the electrode during operation. The Quantity of light through the fiberoptics may not be sufficient. To apply this technique to clinical practise, there were many problems to be solved. However, this may be one of the possible monitor of anesthetic depth and brain hypoxia in future.