Fibre-optic ECG monitoring instrument for use in the operating room

When the ESU is activated, the ECG monitor is exposed to interference generated by the ESU. We analysed this situation to find which of the three possible noise path combinations contributes the most to the noise problem. We showed that the monitoring device should be isolated from both the earth and the AC power line at electrosurgical high frequencies to reduce interference. We therefore propose a fibre-optic ECG monitoring instrument which is ideal for the operating room where high noise performance and excellent electrical safety are indispensable.