| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
In the first experiment, the effects of volatile anesthetics, i.e. methoxyflurane, halothane, enflurane and isoflurane, on the electroretinogram (ERG) were studied in rabbits. The ERG was analyzed in terms of the a-wave and the first oscillatory component (OP-1) in the b-wave. The OP-1 peak latency showed a significant dose-related prolongation when anesthetic end-tidal concentrations were in excess of 0.8 MAC. The amplitudes of the a-wave and the O-1 decreased in dose-dependent manners, but their changes were less striking than those of the OP-1 latency. The peak latency of the a-wave remained unchanged.
Using the same preparation, the effects of hypoxia were studied. After 3 min apnea, both peak latencies of the a-wave and the OP were prolonged and the amplitude of the a-wave decreased, while the anesthetics prolnged only the OPs' latencies. Hypoxic changes were observed under PaO2 less than 50 torr. Therefore, ERG would be a useful intraoperative monitoring to brain hypoxia and anesthetic depth.
In the second experiment, anesthetic effects on the ERG were studied using a bull frog eye-cup preparation.
Finnaly, we intended to develop the ERG monitoring system for anesthetic depth and brain hypoxia. For this purpose, we designed a special contact lens type ERG electrode equipped with a optical fiber which was connected to Xe strobophotic light sourse. In addition, a signal processing program was induced for rapid diagnosis. The clinical evaluation of the system is under the investigation.
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