Page 462 - Flexible Robotics in Medicine

456 Chapter 20

patency of the indwelling urinary catheter [1]. CBI input is adjusted per the gross hematuria
levels present in the discharge, which physically alter the color of the discharge [1]. Current
regulation of CBI input is done manually, which may give rise to many health issues including,
but not limited to, patient discomfort, cystospasm, and hemorrhage due to perception bias [2]
or lack of manpower conduct routine adjustments. The problem of manual adjustment of CBI
could be addressed with an automated CBI process. Automated sensing and regulation can be
used to overcome perception bias and reduce human error.

The sterile solution (0.9% NaCl) in the CBI is regulated via the T-U-R-Y-set (irrigation set).
The T-U-R-Y-set includes a roller clamp that regulates the flow from the NaCl bags. The roller
clamp (manual CBI control) regulates the sterile solution flow rate by guiding a cylindrical
object (blue wheel) along an inclined plane. The inclined plane provides a gradual transition in
the distance between the edge of the cylindrical object (blue wheel) and the base of the roller
clamp support (white casing). The sterile solution flow rate is regulated through the motion of
the cylindrical object (blue wheel) along the base of the roller clamp support (white casing),
which compresses the sandwiched tube at different amounts of compression along the axis of
the base of the roller clamp support (white casing). This method of flow control is mechanical
and approximate, as there are no markings to indicate the degree of compression. The result off
the manipulation of the roller clamp can only be observed by the resultant flow downstream
from the roller clamp. In CBI, the regulation of flow rate is dependent on the level of gross
hematuria present in the urine discharge of the patient. Therefore it is noted that the
measurement of gross hematuria levels in urine discharge is subjected to perception bias, as it is
determined by the perceiver’s judgment of color and that the regulation of sterile solution flow
rate is not optimized due to rough guidelines of manual flow rate control is current practice. In
the case study, the gross hematuria levels were measured via a color monitor for the urinary
discharge and analyzed with a computer microprocessor [2]. The flow rate of the sterile solution
was regulated with a mechanical flow rate controller [2]. Therefore it is an essential need to
have smart valves to regulate the flow rate during biomedical applications [3,4] such as CBI.

Hydrogels are 3D polymer networks that strongly absorb water, approaching 99%
concerning the weight of the hydrogel mass [5]. Due to this ability, hydrogels can
experience reversible [6] volume transitions up to 10 times in volume [5]. The entropic and
energetic components of hydrogels are very dependent on temperature [5]. Thus
temperature variation can be used as stimuli to affect the swelling degrees of such
hydrogels [5], resulting in volume transitions. Hydrogels can function in solely aqueous
media [5], which may enable such hydrogels to function as in-built valves in the tubes used
in the CBI process, where the media is the sterile solution. Hydrogel valves present many
beneficial qualities in their role as valves [6]. Thus the incorporation of such hydrogel
valves will not require the setup of the CBI process to be needlessly complicated. The
ability to withstand relatively high pressures validates its ability to be used as a valve in the
CBI process where there is pressure experienced by the hydrogel valve due to the presence