Interference No. 103,197
the target vessel or a vessel which leads to the target
cardiac chamber, e.g., a femoral artery or jugular vein.
Kapany also describes using a fiber optics catheter
inside a hypodermic needle to measure oxygen in peripheral
vessels:34
This remote spectrophotometer using fiber optics has
also been used for the measurement of dye concentration.
Since the return signal on the instrument is a direct
function of the flow velocity, it should be possible,
with appropriate calibrations, to deduce the flow
velocity. With appropriate designs of catheter probes,
it is possible to use this technique for long-term
monitoring of oxygen saturation within peripheral
vessels. Figure 7.26a shows a photograph of a catheter
that has a hypodermic needle at the tip.
Kapany’s only discussion of measuring the oxygen saturation of
blood in tissue (as opposed to an artery, vein, or cardiac
chamber) is the following discussion of a non-invasive, clip-
on oximeter probe:
Figure 7.26b shows another catheter design for precise
ear oximetry. In this case, the fiber bundle is divided
in two parts to provide sharp curves to the bundles so
that one end may be placed in front of the ear lobe and
the other in back of the ear lobe. [Page 197, lines 5-
8].
Section 3 concludes with the following paragraph:
The in vivo oximeter has been discussed at some
Paragraph bridging pages 195 and 197.34
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