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407
Influence Efficiency Drainage
of the Stopcock of Percutaneous Catheters:
Laboratory
Evaluation
on the
.
Horacio
B. D’Agostino1 Yong Park1 J. Philip Moyer&
Eric
2
Robert
Brian
B. Sanchez1
W. Goodacr& Yun
Marcelo
Hwan
Vasconcellos
Kim1
Vieira1
.
The effects of stopcocks on percutaneous fluid drainage were tested in a laboratory model by using a standard stopcock (6-French inner diameter) and a prototype stopcock (9-French inner diameter) connected to 8-, 10-, 12-, 14-, and 16-French catheters. Catheters were immersed in water alone or in viscous fluid with particulate matter, and the system was connected to low wall suction or gravity drainage. The average volume of fluid aspirated in a given period with and without a stopcock was compared for each catheter. The standard stopcock decreased drainage efficiency for these catheters by
13-42%. This decreased drainage efficiency was worse with the larger catheters. Particulate fluid blocked the stopcock connection for all catheters. With the prototype stopcock, drainage of water alone was reduced by 0-9% for the catheters of different sizes. Particulate fluid did not obstruct the prototype stopcock with any size catheter. With gravity drainage, the volume of water aspirated was reduced by 12-42% with the standard stopcock and by 3-6% with the prototype stopcock. These data suggest that stopcock connections greatly influence the efficiency of the percutaneous drainage systems. Stopcocks with larger inner diameters may improve drainage over that achievable with the stopcocks that are currently available. AJR
159:407-409,
Percutaneous
August
catheter
1992
drainage
systems
include
a three-way
stopcock
and a
connecting tube attached to suction or to a drainage bag. Stopcocks are used routinely, regardless of the indication for drainage or the type and size of catheter. Irrigation of the catheter through a stopcock maintains the catheter’s patency, and it decreases the risk of occlusion and secondary bacterial contamination of the drainage system [1]. Additionally, the use of a stopcock prevents spillage of fluids while the catheter is being flushed, allowing isolation of body substances, one of the basic universal precautions. Reduction offlow or obstruction of catheters and stopcocks by particulate matter or stone fragments can hinder drainage of abscesses, biliary or urinary [1 3-5]. To address these problems, we assessed the effect of the stopcock on the efficiency of catheter drainage systems in an experimental model. We report the results of this study, discuss its potential impact, and recommend ways to improve the efficiency of drainage via catheters. ,
Received November 20, revision February 24, 1992. 1
Department
of Radiology,
1991
;
accepted
after
University of Califor-
nia, San Diego, CA 92093. Address reprint requests to H. D’Agostino, Department of Radiology (H-756), UCSD Medical Center, 225 Dickinson St., San Diego, CA 92103. 2 Department of Medicine, Division of Gastroen-
terology, University Jolla, CA 92093.
of Califomia,
0361 -803X/92/1 592-0407 C American Roentgen Ray Society
San Diego, La
Materials
and Methods
The experimental model used French; length, 20 cm) and sump
both single-lumen catheters (sizes
drainage catheters (sizes 8- and i 0i 2-, i4-, and i6-French; length, 30 cm)
(Medi-tech, Watertown, MA). The inner diameter and the number and size of drainage holes for each catheter are given in Table i Although double-lumen catheters of sizes i2- to i6French were used, the sump port was occluded so that we could better address the influence .
of the stopcock as the sole variable in a single-lumen system. In the first phase of the experiment, a standard stopcock with a 6-French
(Baxter,
Irvine, CA) was connected
in series to both the catheter
inner
and continuous
diameter
low wall
D’AGOSTINO
408
AJA:159,
Catheter
Suction
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ET AL.
I
1992
Fig. 1.-A and B, Diagrams of a stopcock drainage system show standard stopcock with 6-French inner diameter (A) and prototype stopcock with 9French Inner diameter (B). Three-way stopcock is shown longitudinally and in cross section (third opening has been
Suction
6-French
August
eliminated
9-French
for clarity).
9french
A
B
TABLE
1: Characteristics
Catheter
Size
of Catheters
Inner Diameter
TABLE 2: Comparisons of Average and Without Standard Stopcock
Studied
Number
of Holes
Catheter Size (French)
Size of Holes
(mm)
(French)
(mm)
8 io
i.5
5
2xi
2.3
4
3x2
i2
2.3
5
4x2
i4
2.8
5
5x2
16
3.6
5
6x2
was
trials.
removed
drained
The experiment
from
by each catheter,
compared,
was repeated
the drainage both
io 12 i4 i6
experiment,
i4
below
the fluid
level.
The
volumes
stopcock, with the standard stopcock, cock were measured and compared.
catheter
of fluid
drained
without
and with the prototype
standard solution
volumes
stop-
with and without
stopcock performance for all catheters for draining water alone, ranging from a decrease of 13% for 8-French catheters to a decrease
particles
in one of three trials for 8-French
was
TABLE
3: Comparison
Without Prototype
.
Stopcock
Catheter Size (French)
not
13 26 25 30 42
Fluid i6
-
53
-
43
-
66
-
i 20
-
calculated
of Average
for
Volume
particulate
fluid
Aspirated
because
of
with and
Stopcock Volume Aspirated
With Stopcock
(ml)
Without
Stopcock
.
Drainage Difference (% decrease)
Water
i2 i4
i8i 396 380 460
i83 396 383 490
i6
563
6i6
8
a
stopcock for both water and particulate viscous are shown in Table 2. Incorporating a standard into the drainage system caused a decrease in
When stopcock
difference
at stopcock.
io
of fluid aspirated
of 42% for 1 6-French catheters. fluid was drained, the standard
Drainage
occlusion
a
Results
The average
i6
the two
drainage system was used with a prototype stopcock that had a 9French inner diameter (Cook, Inc., Bloomington, IN) (Fig. 1B). As in the first phase, the average volumes drained with each catheter with and without the stopcock were compared, and the percentage of the difference between the two volumes was calculated. These experiments were repeated with gravity drainage instead of low wall suction. Catheters were again immersed in water and in viscous fluid with particles. The collection container was placed 20 cm
i2
were
between
an identical
with
Drainage Difference (% decrease)8
i83 396 383 460 6i6
Occludedini of 3 trials Occludedin2 of 3 trials Occludedin3 of 3 trials Occluded in 3 of 3 trials Occluded in 3 of 3 trials
io
a
of the
Without
Particulate 8
volumes
the stopcock,
of the difference
With Stopcock
(ml)
Aspirated
Water
after the stopcock
The average
with and without
and the percentage
volumes was calculated. In the second phase
system.
Aspirated
i60 290 286 320 356
8
suction (50 mm Hg) (Fig. i A). Each catheter was immersed in water alone and then in particulate viscous fluid for three trials of i mm each. The particulate viscous fluid was prepared by mixing water and ultrasound gel (3:2 v/v mixture) with i 0 g of crumbled white bread. The particles of bread were 1-5 mm in size, and the viscosity of the solution was 135 centistokes. The average volumes of the water and the particulate fluid drained with each catheter were noted for each of the three
Volume
Volumes
Particulate