title: Total radiated power, infrared output, and heat generation by cold light sources at the distal end of endoscopes and fiber optic bundle of light cables.
abstract: BACKGROUND
  Skin burns and ignition of drapes have been reported with the use of cold light sources. The aim of the study was to document the temperature generated by cold light sources and to correlate this with the total radiated power and infrared output.
  
  
  METHODS
  The temperature, total radiated power, and infrared output were measured as a function of time at the end of the endoscope (which is inserted into the operative field) and the end of the fiber optic bundle of the light cable (which connects the cable to the light port of the endoscope) using halogen and xenon light sources.
  
  
  RESULTS
  The highest temperature recorded at the end of the endoscope was 95 degrees C. The temperature measured at the optical fiber location of the endoscope was higher than at its lens surface (p < 0.0001). At the end of the fiber optic bundle of light cables, the temperature reached 225 degrees C within 15 s. The temperature recorded at the optical fiber location of all endoscopes and light cables studied rose significantly over a period of 10 min to reach its maximum (p <0.0001) and then leveled off for the duration of the study (30 min). The infrared output accounted only for 10% of the total radiated power.
  
  
  CONCLUSIONS
  High temperatures are reached by 10 min at the end of fiber optic bundle of light cables and endoscopes with both halogen and xenon light sources. This heat generation is largely due to the radiated power in the visible light spectrum.
authors.affiliation: Department of Surgery, Ninewells Hospital and Medical School, University of Dundee, Scotland.
authors.forename: C
authors.initials: C
authors.lastname: Hensman
authors.forename: G B
authors.initials: GB
authors.lastname: Hanna
authors.forename: T
authors.initials: T
authors.lastname: Drew
authors.forename: H
authors.initials: H
authors.lastname: Moseley
authors.forename: A
authors.initials: A
authors.lastname: Cuschieri
mesh_terms: D003080:Cold Temperature; D019723:Endoscopes; D005336:Fiber Optic Technology; D006358:Hot Temperature; D006801:Humans; D007259:Infrared Rays; D008029:Lighting; D055100:Optical Fibers