Usefulness of a developed four-channel EGG system with running spectrum analysis

Electrogastrography (EGG) is a method of measuring action potentials on the abdomen. It is noninvasive, inexpensive and easy to measure. However, the EGG signal has a very low frequency (0.05 Hz) and an extremely low amplitude (10-100 microV). Consequently, its measured waveform is difficult to analyze and it is not yet completely understood. In this study, a four-channel EGG measurement system was built to measure the action potential of the stomach. This system was compared with the commercially available one-channel Digitrapper EGG. The 3 cpm percentages were compared between the best channel of the four-channel system and channel 1, whose electrode position was similar to the commercially available one-channel system for normal subjects. The average 3 cpm percentage of the best channel and channel 1 for preprandial measurement was 89.5% and 83.2%, respectively, and this was statistically significant (p < 0.001). Also the average 3 cpm percentage of the best channel and channel 1 for postprandial measurement was 90.4% and 76.5%, respectively, and this was statistically significant (p = 0.003). From these results, it can be concluded that a multi-channel EGG system is required for better EGG measurement.

How Much are Anesthesiologists Exposed to Electromagnetic Fields in Operating Rooms? / 대한마취과학회지

BACKGROUND: So many electronic devices have been introduced in the operating room. However, little was known about the hazards of electromagnetic fields (EMF) to the human body. We have studied about how much the anesthesiologists are exposed to EMF. METHODS: In 19 operating rooms of our hospital, the intensity of magnetic fields was measured by an ELF (Extremely low frequency) field strength measurement system. The distances were 30 cm, 50 cm and the anesthesiologist's proximity to the monitoring devices. RESULTS: The average strength of 19 operating rooms were 2.22 +/- 1.13 mG at 30 cm from the monitors, 1.29 +/- 0.84 mG at 50 cm and 1.00 +/- 0.78 mG at the anesthesiologist's stand. CONCLUSIONS: We found that in some of our operating rooms the exposure to EMF was measured above Sweden's TCO limit which has been accepted as the EMF radiation rule for computer monitors. Although the hazards of EMF have not been definitely confirmed yet, the effort not to be exposed to EMF should be considered by anesthesiologists.