Background: When infrared (IR) radiation is conducted through water, its long-wave parts (called IR-B and IR-C) are filtered out in favour of the short-wave IR-A band. Since the former are normally absorbed in the outer layers of skin, water-filtering results in a reduced risk of superficial burns and a better penetration into tissues. This effect which in solar radiation results from its passing through the water vapour of the earth's atmosphere, has now been successfully imitated in radiant heaters. In this study, the potential benefits of water-filtered as compared to conventional infrared radiation in obstetrics and neonatology were examined.
Materials and methods: To this end, three methodological approaches were made, namely: 1. Comparative physical measurements of radiant power density in several clinically used IR-sources, 2. physiological simulation experiments on the surface and depth effects of either type of radiation (performed on human adults and an artificial tissue phantom), and 3. clinical observations on the protective effects of the novel IR-A-radiators in incubator nursing and primary care of preterm neonates.
Results and discussion: Although the absolute radiant power density was equivalent in a conventional and a novel heating device, the IR-A radiation proved to result in a markedly reduced superficial overheating of tissues. In addition, it exceeded conventional IR radiation in its ability to pass through incubator walls, thus lowering the risk of cooling in preterm neonates during nursing procedures. Moreover, when used as a complementary source of heat in the delivery room, IR-A radiation exerted a preventive effect against hypothermia during the subsequent transport of patients to the neonatal intensive care unit, probably due to the rapid build-up of heat deposits in peripheral tissues.
Conclusions: In view of these benefits which are reinforced by a greatly diminished evaporation effect, water-filtered IR-radiation seems to make a promising contribution to the thermal protection of preterm neonates.