title: Non-cladding optical fiber is available for detecting blood or liquids.
abstract: OBJECTIVE
  Serious accidents during hemodialysis such as an undetected large amount of blood loss are often caused by venous needle dislodgement. A special plastic optical fiber with a low refractive index was developed for monitoring leakage in oil pipelines and in other industrial fields. To apply optical fiber as a bleeding sensor, we studied optical effects of soaking the fiber with liquids and blood in light-loss experimental settings.
  
  
  METHODS
  The non-cladding optical fiber that was used was the fluoropolymer, PFA fiber, JUNFLON™, 1 mm in diameter and 2 m in length. Light intensity was studied with an ordinary basic circuit with a light emitting source (880 nm) and photodiode set at both terminals of the fiber under certain conditions: bending the fiber, soaking with various mediums, or fixing the fiber with surgical tape. The soaking mediums were reverse osmosis (RO) water, physiological saline, glucose, porcine plasma, and porcine blood. The light intensities regressed to a decaying exponential function with the soaked length.
  
  
  RESULTS
  The light intensity was not decreased at bending from 20 to 1 cm in diameter. The more the soaked length increased in all mediums, the more the light intensity decreased exponentially. The means of five estimated exponential decay constants were 0.050±0.006 standard deviation in RO water, 0.485±0.016 in physiological saline, 0.404±0.022 in 5% glucose, 0.503±0.038 in blood (Hct 40%), and 0.573±0.067 in plasma. The light intensity decreased from 5 V to about 1.5 V above 5 cm in the soaked length in mediums except for RO water and fixing with surgical tape.
  
  
  CONCLUSIONS
  We confirmed that light intensity significantly and exponentially decreased with the increased length of the soaked fiber. This phenomena could ideally, clinically be applied to a bleed sensor.
authors.affiliation: Department of Medical Informatics, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa 252-0373, Japan. take@kitasato-u.ac.jp
authors.forename: Akihiro
authors.initials: A
authors.lastname: Takeuchi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Miwa
authors.forename: Masuo
authors.initials: M
authors.lastname: Shirataka
authors.forename: Minoru
authors.initials: M
authors.lastname: Sawada
authors.forename: Haruo
authors.initials: H
authors.lastname: Imaizumi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sugibuchi
authors.forename: Noriaki
authors.initials: N
authors.lastname: Ikeda
mesh_terms: D000818:Animals; D004867:Equipment Design; D005336:Fiber Optic Technology; D006470:Hemorrhage / Q000175:diagnosis* / Q000209:etiology; D006801:Humans; D066298:In Vitro Techniques; D008027:Light; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000706:statistics & numerical data; D009339:Needles / Q000009:adverse effects; D055100:Optical Fibers; D010969:Plastics; D006435:Renal Dialysis / Q000009:adverse effects*; D013552:Swine
chemical_list: D010969:Plastics