Clogging of Drainage Catheters: Quantitative and Longitudinal ...

Radiology
grees of catheter clogging between different
catheters.
We found a discrepancy between the
curves generated by the fitting Equation
(4) and those generated by the Poiseuille
equation (Eq [2]). Furthermore, intracatheter
pressure was found to be proportional
to the square of the infusion rate
and not to the infusion rate, as indicated
by fitting Equation (4). This discrepancy
might be attributed to technical factors
or to the fact that the system is not modeled
perfectly by the Poiseuille law. The
reasons for these differences remain unknown,
and further study is required.
In summary, we propose a method for
in vivo evaluation of the effectiveness of
a drainage catheter, which is based on
the application of the Poiseuille law.
With this method, the flow resistance of
a catheter can be determined quantitatively;
thus, it offers a means of quantifying
the degree of clogging or the anticlogging
effect of drainage catheters. This
method can be used for comparative and
longitudinal studies concerning the evaluation
of drainage procedures or the development
of new catheters.
Practical application: By applying the
noninvasive method used in this study,
flow resistance through multiple drainage
catheters can be compared over time
in one animal, which provides quantitative
information about the gradual obstruction
of catheters. This information
is critical for the evaluation of drainage
procedures or development of new catheters
with anticlogging effects, such as
those made with novel biomaterials and
drug-delivery systems. Furthermore, this
method does not preclude analyses based
Figure 5. Images show internal surfaces of drainage catheters after the catheters were withdrawn.
(a) Stereomicroscopic image shows debris that plugs the catheter side holes and lumen,
which were irrigated one time per day. (b) Scanning electron microscopic image shows a catheter
that was irrigated two times per day. Note the irregular surface caused by the debris (D). (Original
magnification, 170.)
on weight or morphologic changes after
the catheter is withdrawn.
Acknowledgments: We thank Hyuk Jae
Choi, Myoung Soo Kim, RT, and Hyun Jung
Lee, RT, for their technical assistance in animal
preparation. We are grateful to Myoung Jin
Jang, PhD, for her help with the statistical
analysis.
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838 Radiology June 2003 Lee et al