Aasen S E, Johnsson A, Bratlid D, Christensen T
Department of Physics, University of Trondheim, Norway.
Biol Neonate. 1996;70(5):249-64. doi: 10.1159/000244374.
In this study the magnetic flux density in and around incubators of a neonatal intensive care unit was registered and mapped. The mean 50-Hz magnetic flux densities in an incubator were typically in the range of 0.2-1 microT, with maximum values around 1.5 microT. For 1 incubator, harmonics contributed to the field substantially. The field levels varied depending on the type of equipment, the positioning of the electronics and the position of the 240-volt main plugs. The positioning of the infant in the incubator and the precise mattress position in the incubator affected the magnetic flux density to a great extent, as did the positioning of the electronic monitoring and treatment equipment. The flux density values found were fairly low as compared to magnetic field levels present at some work places where high electric currents are used. In intensive care units, however, the duration of exposure can be very long, especially for premature infants. The fields can also be compared with the magnetic field levels of residences and are then approximately 100 times higher. Further studies are necessary -it seems important to record magnetic fields and attempt to reduce the levels. Such a reduction can be achieved by reducing the field from the incubators but also by changing the electronic equipment around the incubators or increasing the distance to the incubator. Further research should of course also study any mechanism by which magnetic fields can affect cells and organisms. Compared to the risks many of these infants are exposed to, it is difficult to say whether the magnetic field levels measured can represent a significant additional risk factor. However, this is an area where one should adopt a prudent avoidance strategy, particulary considering how easily these fields can be reduced, mainly through redesign of the various equipment.
在本研究中，对新生儿重症监护病房内及周围保温箱的磁通密度进行了记录和测绘。保温箱内50赫兹的平均磁通密度通常在0.2 - 1微特斯拉范围内，最大值约为1.5微特斯拉。对于1个保温箱，谐波对磁场有显著贡献。磁场水平因设备类型、电子设备的位置以及240伏主插头的位置而异。婴儿在保温箱内的位置以及保温箱内床垫的确切位置在很大程度上影响磁通密度，电子监测和治疗设备的位置也是如此。与一些使用强电流的工作场所存在的磁场水平相比，所测得的磁通密度值相当低。然而，在重症监护病房，暴露时间可能非常长，尤其是对于早产儿。这些磁场也可与住宅的磁场水平进行比较，其强度大约高出100倍。有必要进行进一步研究——记录磁场并尝试降低其水平似乎很重要。通过降低保温箱产生的磁场、改变保温箱周围的电子设备或增加与保温箱的距离都可以实现这种降低。当然，进一步的研究还应探讨磁场影响细胞和生物体的任何机制。与这些婴儿面临的许多风险相比，很难说所测得的磁场水平是否会构成一个显著的额外风险因素。然而，这是一个应采取谨慎规避策略的领域，特别是考虑到这些磁场通过各种设备的重新设计能多么容易地降低。
