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• Light-blue vs blue lights in phototherapy
  Giovanni Agati
  Published on: 22 March 2016
• Recent innovation in phototherapy
  Girish Gupta
  Published on: 22 March 2016

• Published on: 22 March 2016

  Light-blue vs blue lights in phototherapy

  • Giovanni Agati, Researcher
  • Other Contributors:
    • Finn Ebbesen, Riccardo Pratesi

  Dear Editor

  We would like to reply to the eLetter “Recent innovation in phototherapy” by Gupta et al.[1]

  It is well known that the action mechanism of neonatal jaundice phototherapy is not the simple photodestruction of bilirubin. It involves the phototransformation of bilirubin to more water-soluble compounds, their diffusion rate from the skin and peripheral blood vessel to circulation and th...

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  Dear Editor

  We would like to reply to the eLetter “Recent innovation in phototherapy” by Gupta et al.[1]

  It is well known that the action mechanism of neonatal jaundice phototherapy is not the simple photodestruction of bilirubin. It involves the phototransformation of bilirubin to more water-soluble compounds, their diffusion rate from the skin and peripheral blood vessel to circulation and their rate of excretion from the organism. Therefore, the efficiency of a light source in reducing bilirubin can not adequately be estimated in an in vitro closed-system. Experimental trials by irradiating blood samples would not have added any useful information for designing the clinical comparison of the new turquoise fluorescent lamp versus blue lamps. The in vitro studies have been fundamental to understand the photochemistry of bilirubin. Comparative studies of phototherapy fluorescent lamps on buffer solution of bilirubin complexed to human serum albumin were performed about 20 years ago.[1,2] The efficiency of new emission bands in bilirubin photochemistry in vitro can be theoretically predicted on the basis of previous reported data.[3]

  The distance from the phototherapy apparatus to the surface of the infants was about 32 cm, as this was the minimum possible distance when the infant were treated in an incubator. Two thirds of the infants were treated in that way, therefore, we were obliged to choose that level of irradiance for our study. Of course, in the routine phototherapy when infants can be treated in a bassinet the lamp-neonate distance must be reduced as much as possible taking however care of avoiding any burn risk [5]. Further increases of the irradiance to the infant’s body by coupling conventional lamp phototherapy with fiber optics phototherapy and by the use of reflecting covers as Gupta et al. mentioned is recommended to increase phototherapy efficiency.

  The new turquoise fluorescent lamp used was developed by OSRAM (type number L18W/L131-UVS). It is a standard 590 mm length, 26 mm diameter tube made by the well-known fluorescent lamp technology: the tube is filled with an inert gas and small amounts of mercury, while the internal surface of the tube is cover by a mixture of phosphors. Light emitted by excited mercury molecules in the gaseous state is absorbed by the phosphor layer and partially remitted as the colored fluorescent light. More information about the new fluorescent lamp can be obtained contacting Dr. Armin Konrad, OSRAM GmbH, FL/CFL D-A, Phosphor Application, Augsburg (Germany), Fax: +49 821 588-4218, email: Armin.Konrad@osram.de.

  We would like to conclude recalling the importance of the spectral emission (color) of the light source, together with the irradiance levels, in the neonatal jaundice phototherapy and then suggesting to shift from a blue to a light-blue light.

  References

  [1] Gupta G, Kinley T, Nair MNG. Recent innovation in phototherapy [electronic response to Ebbesen et al. Phototherapy with turquoise versus blue light] archdischild.com 2004http://fn.bmjjournals.com/cgi/eletters/88/5/F430#249

  [2] Ennever JF, Sobel M, McDonagh AF, et al. Phototherapy for neonatal jaundice: in vitro comparison of light sources. Pediatr Res 1984;18:667-670.

  [3] Agati G, Fusi F, Pratesi R, Configurational photoisomerization of bilirubin "in vitro". II. A comparative study of phototherapy fluorescent lamps and lasers. Photochem Photobiol 1985;41:381-392.

  [4] Agati G, Fusi F, Donzelli GP, et al. Quantum yield and skin filtering effects on the formation rate of lumirubin. J Photochem Photobiol B 1993;18:197-203.

  [5] Maisels MJ, Watchko JF, Treatment of jaundice in low birthweight infants. Arch Dis Child Fetal Neonatal Ed 2003;88:F459-F463.

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  Conflict of Interest:
  None declared.

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• Published on: 22 March 2016

  Recent innovation in phototherapy

  • Girish Gupta, Associate Professor In paediatrics
  • Other Contributors:
    • Kinley T, MNG Nair.

  Dear Editor

  We read with interest the article “Phototherapy with turquoise versus blue light” by F Ebbesen et al.[1]

  The article addresses to the usefulness of turquoise light and its relative advantage over conventional blue light in view of its equal efficacy in reducing serum bilirubin at a lesser irradiance and has stated the harmful mutagenic effects associated with blue light. However, we wou...

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  Dear Editor

  We read with interest the article “Phototherapy with turquoise versus blue light” by F Ebbesen et al.[1]

  The article addresses to the usefulness of turquoise light and its relative advantage over conventional blue light in view of its equal efficacy in reducing serum bilirubin at a lesser irradiance and has stated the harmful mutagenic effects associated with blue light. However, we would like to seek clarifications on the following points, which are of research and clinical utility.

  The article did not mention whether any experimental trial was carried out with turquoise light on the blood samples before proceeding with the human trial, if so whether the trial had similar results. Secondly, the distance from the phototherapy apparatus was kept at 32cm. We would like to know that what has guided the authors to choose this specific level, the fall in serum bilirubin would have been more effective if the distance was kept at lower levels, as lesser distance produces more irradiance.[2]

  Further we are keen to know how turquoise light was made? What extra accessories are required while using this light, its availability, and how will it fare with blue light in terms of cost? We in our experimental study by Gupta et al have innovated a simple cheap cost effective measure that could generate significantly higher irradiance in double surface phototherapy by the use of photoreflectant covers. (3) The maximum irradiance generated was 76.28 microwatt/cm²/nm and the gain in irradiance was not associated with statistically significant increase in temperature inside the phototherapy unit. Apparently its acceptance by the NICU staff was also better as the glare-associated problems were reduced by use of the covers.

  We solicit author’s comments for more effective answers to such an important research domain.

  References

  (1) F Ebbesen, G Agati, R Pratesi. Phototherapy with turquoise versus blue light. Arch Dis Child Fetal Neonatal Ed 2003; 88; F430-F431.

  (2) Tan K L. The pattern of bilirubin response to phototherapy for neonatal hyperbilirubinemia. Pediar Res 1982; 16:670.

  (3) Gupta G et al. Unmatched evolution in phototherapy. [Unpublished work, to be presented in Annual Convention of National Neonatal Forum of India].

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  Conflict of Interest:
  None declared.

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