医療機関でのLED照明の安全な導入に向けた電磁環境面での評価

―医用テレメータへの影響の検証―

抄録

Light Emitting Diode (LED) lamps have become widespread in the clinical settings. However, electromagnetic noise from LED lamps could be problematic. In hospitals, the reception level of signals from medical telemeters might decrease after replacing traditional lighting with LED lamps. To investigate the effects of noise radiated from LED lamps on medical telemeters, we measured the electric field intensity of 34 types of LED lamps. Many of them emit 400 MHz band noise, and some types of LED lamps had increased floor level noise of 30 dB. We also observed artifact noises on electrocardiogram and respiratory waveforms when an LED lamp was placed next to the patient monitor. This effect was observed only when a medical telemeterʼs transmitter and a LED lamp were placed quite close. When approximately 50 cm apart, patient monitorsʼ signals were received normally. In hospitals, AC power supply cables and lamps are often placed near transmission cables, including leaky coaxial cables (LCX), as antenna of the patient monitors. To prevent interference with medical telemeters, selecting low noise LED lamps and maintaining sufficient separation between LED lamps and receiving antennas or LCX is necessary.