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Proceedings Paper

Intravascular Fiberoptic Detection Of D[sub]2[/sub]O Concentration In Blood.
Author(s): J. Bock; E. Gersing; F. Sundmacher; G. Hellige
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Paper Abstract

The recent development of low-loss infrared zirconium fluoride fibers allows remote sensing of infrared signals. In this paper a detection device for the intravascular measurement of substances absorbing in the infrared wave length range is described. The applicability of the technique is demonstrated by the measurement of small concentrations of heavy water (D20) in blood. The method is based on the well-known fact that D20 strongly absorbes radiation in the 4 μm range while H2O and blood are comparably well transmitted at that wave length. A catheter was designed that can be inserted in arterial blood vessels. The catheter tip is constructed such that the radiation is guided by the fiber to a gold reflector. Between the reflector and the fiber, blood is withdrawn through a gap of ca. 0.1 mm. The radiation thus passes the medium twice and is guided back to the same fiber. Concentrations below 1 ml D20/1000 ml blood can be determined accurately and indicator kinetics can be recorded with time constants of the entire system below 0.05 s. The advantages of this technique are the low withdrawal rate and neglectable delay of the recorded indicator kinetics and no need for reinfusion of blood. D20 has been used to determine physiological parameters such as extravascular lung water, cardiac output and total body water. The study demonstrates that such measurements are feasable with the described fiberoptic device and that the fiberoptic approach offers distinct advantages over conventional blood withdrawal methods with external analysis. Injectate volumes as small as 0.05 ml/kg body weight are sufficient to obtain indicator kinetics with acceptable signal to noise ratio. By use of appropriate filters concentrations of other substances and their intravascular kinetics can be measured. According to their physicochemical properties a variety of information on physiological parameters appears to be accessible with this approach.

Paper Details

Date Published: 21 June 1988
PDF: 7 pages
Proc. SPIE 0906, Optical Fibers in Medicine III, (21 June 1988); doi: 10.1117/12.945273
Show Author Affiliations
J. Bock, Universitat Gottingen (Germany)
E. Gersing, Universitat Gottingen (Germany)
F. Sundmacher, Universitat Gottingen (Germany)
G. Hellige, Universitat Gottingen (Germany)

Published in SPIE Proceedings Vol. 0906:
Optical Fibers in Medicine III
Abraham Katzir, Editor(s)

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