Comparison of Water and Air-Charged Transducer Catheters in the
Evaluation of Cystometrogram Pressures
N.
1Drexel
1
Shah ,
1
Ginzburg ,
N.
D.
1
Morrissey ,
K.E.
2
Whitmore ,
E.
3
Babin ,
T.
3
McKinney
Univ. Coll. of Med., Philadelphia, PA, 2The Pelvic and Sexual Health Institute, Philadelphia, PA., 3Athena Women’s Institute for Pelvic Health, Turnersville, NJ
•  Air-charged (AC) and water-perfused
(WP) catheters have been evaluated for
differences in measuring pressures for
voiding dysfunction.
•  We believe that a single, dual catheter,
and the same experience clinician
throughout the study will provide
analogous point pressures for cough and
valsalva movements in both AC and WP
catheters when analyzed during
cystometrogram (CMG).
Discussion
Results
Introduction
•  Forty women with a mean age of 57 years were recruited
•  Significant correlations were observed between AC and WP pressures (Fig1, Fig 2)
•  Trendline equations comparing AC and WP measurements over distinct bladder fill
regions for cough and valsalva showed a high correlation (average R2=0.91).
•  Average bias (4.7 cmH2O for coughs and 4.1 cmH20 for valsalva) throughout the
measurements.
•  Visual impression of the two overlying measurement methods shows virtually
identical tracings (Fig 3)
•  The outliers on figure two are when the bladder was
empty, and suggests the water pressure are not
accurate until >50mL.
•  Visual graphical impression of the two measurement
methods correlated quite well and suggests that the
clinical utility of either of these technologies is very
similar and in some cases virtually identical.
Figure 1: Cough Peak Pressure Correlation at Various Infused Volumes –
Air v. Water
y = 0.7844x + 32.586
R² = 0.64075
Figure 3: Filling cystometry tracing at an infused volume of 200mL.
Blue: P ura_water, Red: Pves_air.
200
y = 0.8947x + 10.203
R² = 0.9479
y = 0.9029x + 11.803
R² = 0.93254
Objective
150
Beginning (0-50mL)
Air pressure (cmH20)
Mid-test (200-250mL)
To demonstrate the reproducibility of AC
versus WP catheters when measuring
stress point pressures, such as coughs and
valsalva movements, in urodynamic
studies.
Functional Capacity
Y=X
100
50
0
0
50
100
150
200
Water pressure (cmH20)
Methods/Materials
200
y = 1.0686x + 1.1259
R² = 0.90418
y = 1.0381x + 0.1033
R² = 0.97424
150
y = 1.0724x - 2.426
R² = 0.96584
Air pressure (cmH20)
•  Female patients enrolled above the age
of 21
•  Complaints of lower urinary tract
symptoms and were recommended
urodynamic studies for further evaluation
of symptoms.
•  Commercially available AC catheter was
utilized to form a dual catheter to
simultaneously read water and air
pressures within the bladder and urethra
•  Transducer evaluates water pressure
and sends electrical signals to a
urodynamic machine
•  The patient is evaluated with an empty
bladder on CMG, followed by cough and
valsalva maneuvers at bladder volumes
of 50mL, 200mL, and functional
maximum capacity.
•  A comparative analysis was performed
on the maximum stress peak pressures
for valsalva movements and cough.
Figure 2: Valsalva Peak Pressure Correlation at Various Infused Volumes
– Air v. Water
Beginning (0-50mL)
100
Mid-test (200-250mL)
Functional Capacity
Y=X
50
0
0
50
100
Water pressure (cmH20)
150
200
Conclusions
Cystometric pressures measured using air-charged catheters are
comparable with water-filled catheters and clinically can be equally
beneficial.
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