1401 DERMAL BILIRUBIN KINETICS UNDER BLUE AND GREEN LIGHT

Abstract

We investigated the efficacy of green light phototherapy in reducing dermal bilirubin concentrations with the transcutaneous bilirubinometer (TcB). Nine infants (BW 3375±370gms)were treated with green light at a mean age of 55±20 hrs, and five controls (3210±530gms) were exposed to blue light at 73±28 hrs. The intensity of the green (13.5±0.8uw/cm2/nm) and blue (12.8±0.1uw/cm2/nm) lights were comparable. An opaque patch covered a 2.5 cm. area of skin, the source for TcB control values. Seventeen simultaneous measurements were recorded from patched and exposed areas every 15 minutes over a period of four hours and rate of TcB change was calculated for each hour of phototherapy. In both light groups TcB remained unchanged under the skin patch over the four hour period. Data from exposed skin showed that the rate of TcB change in the blue light group was -3.3 in the first, -1.6 in the second, -0.4 in the third, and -0.3 TcB units/hr in the fourth hour. In the green light group this change was -1.9, -1.4, -0.8, and -0.4 TcBU/hr in the respective time periods. At the end of the four hours the absolute decrease was comparable in both groups. These results suggest that these lights are equally effective in reducing dermal bilirubin levels, but may differ in their mode of action.