Abstract
Objectives
To determine whether there are differences in pressure and flow measurements between conventional cystometry (CONV) and ambulatory urodynamic monitoring (AMB) in women with overactive bladder syndrome and urinary incontinence.
Materials and Methods
Retrospective study which included female subjects who underwent both CONV (with saline filling medium) and AMB, separated by less than 24 months, not using medication active on the lower urinary tract and without history of prior pelvic surgery. Both tests were carried out in compliance with the International Continence Society standards. The paired Student’s t test was used to compare continuous variables. Bland-Altman statistics were used to assess the agreement of each variable between both studies.
Results
Thirty women with a median (range) age of 50 (14 - 73) years met the inclusion criteria. AMB was carried out at a mean (SD) of 11 (6) months after CONV. Measurements of pves and pabd at the end of filling, and Qmax were significantly higher from AMB recordings. There were no differences in pdet at the end of filling, pdetQmax or pdetmax during voiding, nor significant difference in Vvoid.
Conclusions
We provide previously undocumented comparative voiding data between CONV and AMB for patients who most commonly require both investigations. Our findings show higher values of Qmax but similar values of pdetQmax measured by AMB which may partly reflect an overall lower catheter caliber, physiological filling but perhaps also more ‘normal’ voiding conditions.
Monitoring, Ambulatory; Complementary Therapies; Female; Urodynamics
INTRODUCTION
Ambulatory urodynamic monitoring (AMB) with natural filling is a useful additional
test for patients with lower urinary tract symptoms that cannot be explained by
findings from a conventional cystometry (CONV) with non-physiological filling (11 van Waalwijk van Doorn E, Anders K, Khullar V, Kulseng-Hanssen S,
Pesce F, Robertson A, et al.: Standardisation of ambulatory urodynamic
monitoring: Report of the Standardisation Sub-Committee of the International
Continence Society for Ambulatory Urodynamic Studies. Neurourol Urodyn. 2000;
19: 113-25.). In adult practice it is predominantly
required for women with urinary incontinence which cannot be categorized by a CONV
although there are limited published data on comparative diagnostic accuracy (22 Webb RJ, Griffiths CJ, Zachariah KK, Neal DE: Filling and voiding
pressures measured by ambulatory monitoring and conventional studies during
natural and artificial bladder filling. J Urol. 1991; 146:
815-8.
3 Heslington K, Hilton P: Ambulatory monitoring and conventional
cystometry in asymptomatic female volunteers. Br J Obstet Gynaecol. 1996; 103:
434-41.
4 Robertson AS, Griffiths C, Neal DE: Conventional urodynamics and
ambulatory monitoring in the definition and management of bladder outflow
obstruction. J Urol. 1996; 155: 506-11.
5 Rosario DJ, MacDiarmid SA, Radley SC, Chapple CR: A comparison of
ambulatory and conventional urodynamic studies in men with borderline outlet
obstruction. BJU Int. 1999; 83: 400-9.-66 Webb RJ, Griffiths CJ, Ramsden PD, Neal DE: Measurement of voiding
pressures on ambulatory monitoring: comparison with conventional cystometry. Br
J Urol. 1990; 65: 152-4.). The
two techniques share basic principles but differ in a number of aspects that may
have a bearing on urodynamic measurements (11 van Waalwijk van Doorn E, Anders K, Khullar V, Kulseng-Hanssen S,
Pesce F, Robertson A, et al.: Standardisation of ambulatory urodynamic
monitoring: Report of the Standardisation Sub-Committee of the International
Continence Society for Ambulatory Urodynamic Studies. Neurourol Urodyn. 2000;
19: 113-25.).
Pressure measurements during AMB are generally obtained using catheter-mounted
microtip transducers positioned in the bladder and rectum rather than air or fluid
filled lines connected to external transducers. These allow greater mobility but are
more prone to artifact. Allowing the patient to be mobile is a key feature of AMB
but the frequent changing of position alters the relative height of the rectal and
bladder transducers making frequent signal quality control during bladder filling
necessary. The change from non-physiological filling to natural filling may alter
detrusor contractility (22 Webb RJ, Griffiths CJ, Zachariah KK, Neal DE: Filling and voiding
pressures measured by ambulatory monitoring and conventional studies during
natural and artificial bladder filling. J Urol. 1991; 146:
815-8.,66 Webb RJ, Griffiths CJ, Ramsden PD, Neal DE: Measurement of voiding
pressures on ambulatory monitoring: comparison with conventional cystometry. Br
J Urol. 1990; 65: 152-4.) and cystometric capacity (77 Vereecken RL, Van Nuland T: Detrusor pressure in ambulatory versus
standard urodynamics. Neurourol Urodyn. 1998; 17: 129-33.). The previous lack of simultaneous uroflow
recording during AMB which hampered interpretation of the voiding phase has been
corrected in current devices that include this facility (44 Robertson AS, Griffiths C, Neal DE: Conventional urodynamics and
ambulatory monitoring in the definition and management of bladder outflow
obstruction. J Urol. 1996; 155: 506-11.,55 Rosario DJ, MacDiarmid SA, Radley SC, Chapple CR: A comparison of
ambulatory and conventional urodynamic studies in men with borderline outlet
obstruction. BJU Int. 1999; 83: 400-9.).
The published literature regarding measurement variation suggests that values for
voiding pressure and maximum flow rate are higher with AMB compared to CONV, and
that voided volume is lower (22 Webb RJ, Griffiths CJ, Zachariah KK, Neal DE: Filling and voiding
pressures measured by ambulatory monitoring and conventional studies during
natural and artificial bladder filling. J Urol. 1991; 146:
815-8.
3 Heslington K, Hilton P: Ambulatory monitoring and conventional
cystometry in asymptomatic female volunteers. Br J Obstet Gynaecol. 1996; 103:
434-41.-44 Robertson AS, Griffiths C, Neal DE: Conventional urodynamics and
ambulatory monitoring in the definition and management of bladder outflow
obstruction. J Urol. 1996; 155: 506-11.). However, a more recent study in men with
possible bladder outlet obstruction with integrated flow rate recording showed no
difference in detrusor pressure at maximum flow
(pdetQmax) (55 Rosario DJ, MacDiarmid SA, Radley SC, Chapple CR: A comparison of
ambulatory and conventional urodynamic studies in men with borderline outlet
obstruction. BJU Int. 1999; 83: 400-9.).
In view of these conflicting findings we set out to determine whether there were any differences in voiding pressure and flow measurements between CONV and AMB with integrated flow rate recording that may be attributable to the different filling rates. We focused on the main patient group in whom AMB is requested: women with overactive bladder syndrome and urinary incontinence. This study will not evaluate the filling phase results.
MATERIALS AND METHODS
Subjects
This was a retrospective cohort study which included subjects assessed over a period of eigth years with the following criteria: 1) Female sex, 2) Investigation for overactive bladder and urinary incontinence, 3) Underwent both CONV and AMB, 4) Interval between CONV and AMB of less than 24 months, 5) Saline filling medium used for CONV (contrast medium may alter Qmax), 6) Not using medication active on the lower urinary tract and 7) No history of prior pelvic surgery. All patients provided written informed consent with guarantees of confidentiality.
Conventional Cystometry
The test was carried out in compliance with International Continence Society (ICS) standards current at the time of testing (88 Schäfer W, Abrams P, Liao L, Mattiasson A, Pesce F, Spangberg A, et al.: Good urodynamic practices: uroflowmetry, filling cystometry, and pressure-flow studies. Neurourol Urodyn. 2002; 21: 261-74.). Bladder and rectal pressures were measured with a fluid-filled 4Fr urethral catheter and a 4Fr catheter with the tip covered with a vented fingercot, respectively. The pressure lines were connected to external transducers placed at the upper edge of the symphysis pubis and zeroed to atmospheric pressure. Filling through a 10Fr urethral catheter was carried out in supine position with 0.9% saline, at a rate of 100 mL/min. Voiding occurred in the sitting position with all catheters in situ.
Ambulatory Urodynamic Monitoring
The test was carried out according to International Continence Society (ICS) standards (11 van Waalwijk van Doorn E, Anders K, Khullar V, Kulseng-Hanssen S, Pesce F, Robertson A, et al.: Standardisation of ambulatory urodynamic monitoring: Report of the Standardisation Sub-Committee of the International Continence Society for Ambulatory Urodynamic Studies. Neurourol Urodyn. 2000; 19: 113-25.) using an in-house recording system (Urolog®, Regional Medical Physics Department, Freeman Hospital, Newcastle upon Tyne, UK). Bladder and rectal pressures were measured with microtransducers mounted on the tips of 6 Fr urethral and rectal catheters (Gaeltec Ltd, Isle of Skye, UK) the latter covered by a vented fingercot. These were calibrated to atmospheric pressure and to 30cmH2O. Both were connected to a portable device that recorded data at a frequency of 1Hz. Filling was carried out physiologically by means of allowing patients to drink sufficient fluid to enable multiple fill-void cycles to be recorded over the course of three hours. Voiding occurred in private, in the sitting position, with maximum flow rate and voided volume measured using a standard gravimetric urine flowmeter.
Subsequently, digital data were transferred to a computer and analysed in detail. Setting used for flow measurement was the same for both study modalities.
Measurements recorded
All CONV measurements were done first and AMB measurements were done blinded to the CONV results. We recorded measurements of intravesical, abdominal (rectal) and subtracted vesical (detrusor) pressures at the end of filling (pves, pabd, pdet), detrusor pressure at maximum flow rate (pdetQmax), maximum flow rate (Qmax), maximum detrusor pressure (pdetmax) and voided volume (Vvoid). When more than one fill–void cycle had been recorded during AMB, measurements from individual cycles were summed and the average taken. Free flows were not considered due to the relative high number of patients that needed to urinate before CONV or that voided low volumes. The following derived parameters were calculated: urethral resistance (UR = pdetQmax / Qmax2), bladder outlet obstruction index (BOOI = pdetQmax – 2 Qmax) and bladder contractility index (BCI = pdetQmax + 5 Qmax) (99 Abrams P: Bladder outlet obstruction index, bladder contractility index and bladder voiding efficiency: three simple indices to define bladder voiding function. BJU Int. 1999; 84: 14-5.). The presence of after-contractions, defined as a terminal rise in detrusor pressure not accompanied by an increase in flow rate, was also examined. No systematic maneuver to exclude artifacts from true after-contractions was done (1010 Cho SY, Yi JS, Park JH, Jeong MS, Oh SJ: Detrusor after-contraction is associated with bladder outlet obstruction. Neurourol Urodyn. 2011; 30: 1361-5.).
Statistical analysis
The paired Student’s t test was used to compare the results of CONV and AMB continuous variables. Data were entered in the Stata 8.1 program (Stata Corporation, 2003) and statistical significance was assumed if p<0.05.
Bland-Altman statistics were used to assess the agreement of each variable between CONV and AMB. Briefly, the difference between the 2 tests was calculated in each patient. Thereafter, a graphical plot of the mean of these differences estimated systematic error (bias) from one test to the other. The standard deviation (SD) of the differences provided an estimate of random variation (1111 Bland JM, Altman DG: Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986; 1: 307-10.).
RESULTS
We identified 30 women being investigated for overactive bladder syndrome and urinary
incontinence who met the inclusion criteria, whose urinary incontinence could not be
categorized by CONV. They had a median (range) age of 50 (1414 Scaldazza CV, Morosetti C: Effect of different sized transurethral
catheters on pressure-flow studies in women with lower urinary tract symptoms.
Urol Int. 2005; 75: 21-5.-73) years and AMB was carried out at a mean (SD) of 11
(66 Webb RJ, Griffiths CJ, Ramsden PD, Neal DE: Measurement of voiding
pressures on ambulatory monitoring: comparison with conventional cystometry. Br
J Urol. 1990; 65: 152-4.) months after CONV. None had severe
genital organ prolapse. The median number of voids analyzed from AMB was 2 (range
11 van Waalwijk van Doorn E, Anders K, Khullar V, Kulseng-Hanssen S,
Pesce F, Robertson A, et al.: Standardisation of ambulatory urodynamic
monitoring: Report of the Standardisation Sub-Committee of the International
Continence Society for Ambulatory Urodynamic Studies. Neurourol Urodyn. 2000;
19: 113-25.
2 Webb RJ, Griffiths CJ, Zachariah KK, Neal DE: Filling and voiding
pressures measured by ambulatory monitoring and conventional studies during
natural and artificial bladder filling. J Urol. 1991; 146:
815-8.
3 Heslington K, Hilton P: Ambulatory monitoring and conventional
cystometry in asymptomatic female volunteers. Br J Obstet Gynaecol. 1996; 103:
434-41.-44 Robertson AS, Griffiths C, Neal DE: Conventional urodynamics and
ambulatory monitoring in the definition and management of bladder outflow
obstruction. J Urol. 1996; 155: 506-11.)
with 9 (10%) of a total of 86 voids being excluded from measurement due to bladder
line displacement (n=5) or Vvoid < 150 mL (n=4). The main symptoms
presented by the patients are given in Table-1.
When comparing the results of CONV and AMB, measurements of pves and pabd at the end of filling, and Qmax were significantly higher from AMB recordings. There were no differences in pdet at the end of filling or in pdetQmax and pdetmax during voiding. There was no statistically significant difference in Vvoid. Related to the difference in measurements of Qmax, all derived urodynamic parameters were significantly different between CONV and AMB. Both BOOI and UR derived from AMB measurements were lower, and BCI was higher (Table-2). Figure-1 shows simple plots of the results of AMB against CONV and Bland-Altman plot for pdetQmax, pdetmax, Qmax and Vvoid . Figure 2 shows Bland-Altman plot for BOOI. There was only 1 patient with a clear after-contraction in CONV (of 32 cmH2O versus pdetmax of 30 cmH2O) and no clear after-contractions recorded on AMB.
Simple plot of the results of conventional cystometry (CONV) against ambulatory urodynamic monitoring (AMB) and plot of the difference between the methods against their mean (Bland-Altman method). A) Detrusor pressure at maximum flow rate, B) Maximum detrusor pressure, C) Maximum flow rate, D) Voided volume
Bladder outlet obstruction index (BOOI): simple plot of the results of conventional cystometry (CONV) against ambulatory urodynamic monitoring (AMB) and plot of the difference between the methods against their mean (Bland-Altman method).
DISCUSSION
We sought to determine whether measured voiding variables from CONV and AMB differed amongst women being investigated for bladder storage symptoms. The study has the following strengths: 1) It studies a homogenous patient population from the commonest group undergoing AMB, 2) It uses a standard ICS approved technique with proper quality control using the same technique each time, 3) AMB was performed with synchronous flow recording, 4) AMB measurements were done blinded to the CONV results and 5) No irreversible treatment was given between studies. The limitations of the study are the following: 1) Retrospective study, 2) AMB was always carried out after CONV rather than in a randomized order, 3) Only women who had a non-diagnostic CONV were included, 4) The studies were separated by a variable time period with the possibility of changes in disease status and 5) Included women who did not generally have symptomatic voiding dysfunction.
The subjects in the study varied in age. This has the benefit of making the results generable across the variety of age groups that require urodynamic evaluation of voiding. Due to small numbers we were unable to describe variation in voiding measurements between age groups although this should not affect our results since we examined intra-individual comparisons.
It is likely that the higher pves and pabd recorded at the end of filling during AMB reflect the predominantly upright position of subjects during the storage phase for AMB. The difference in transducer location, pressure measurement technique, and differential changes in the relative height of the tips of bladder and rectal catheters may have contributed to this difference. Supine filling during CONV results in a negative offset from the reference point of several cmH2O owing to the distance between the bladder and rectal catheter tips. In AMB the microtip transducers are zeroed individually to atmospheric pressure and record true bladder and rectal pressures related to the position of the catheter tips (22 Webb RJ, Griffiths CJ, Zachariah KK, Neal DE: Filling and voiding pressures measured by ambulatory monitoring and conventional studies during natural and artificial bladder filling. J Urol. 1991; 146: 815-8.).
Careful quality control during both CONV and AMB adhering to International Continence Society standards (11 van Waalwijk van Doorn E, Anders K, Khullar V, Kulseng-Hanssen S, Pesce F, Robertson A, et al.: Standardisation of ambulatory urodynamic monitoring: Report of the Standardisation Sub-Committee of the International Continence Society for Ambulatory Urodynamic Studies. Neurourol Urodyn. 2000; 19: 113-25.,88 Schäfer W, Abrams P, Liao L, Mattiasson A, Pesce F, Spangberg A, et al.: Good urodynamic practices: uroflowmetry, filling cystometry, and pressure-flow studies. Neurourol Urodyn. 2002; 21: 261-74.) should be effective in minimizing any systematic error caused by these differences in pves and pabd in subtracted bladder (detrusor) pressure measurements. Reassuringly this was the case for our study with no bias in measurements of pdetmax and pdetQmax between CONV and AMB.
Our protocol for AMB requires synchronized recording of urinary flow rate by direct
wired connection of the uroflowmeter output to the ambulatory measurement box
through an auxiliary channel. Pressure and flow recordings can then be displayed
continuously for measurement. The higher values for Qmax seen with AMB
(on average 33%) might be explained at least partially by the presence of both 4Fr
and 10Fr urethral catheters during CONV. Some evidence in support of this contention
comes from intra-individual comparison of Qmax with and without the
presence of a urodynamic measurement catheter with studies in healthy (1212 Baseman AG, Baseman JG, Zimmern PE, Lemack GE: Effect of 6F urethral
catheterization on urinary flow rates during repeated pressure-flow studies in
healthy female volunteers. Urology. 2002; 59: 843-6.) and symptomatic women (1313 Groutz A, Blaivas JG, Sassone AM: Detrusor pressure uroflowmetry
studies in women: effect of a 7Fr transurethral catheter. J Urol. 2000; 164:
109-14.
14 Scaldazza CV, Morosetti C: Effect of different sized transurethral
catheters on pressure-flow studies in women with lower urinary tract symptoms.
Urol Int. 2005; 75: 21-5.-1515 Costantini E, Mearini L, Biscotto S, Giannantoni A, Bini V, Porena
M: Impact of different sized catheters on pressure-flow studies in women with
lower urinary tract symptoms. Neurourol Urodyn. 2005; 24:
106-10.)
showing relative differences of between 28% and 64% using 6Fr, 7Fr and 9Fr
catheters.
Another potential factor influencing flow rate is Vvoid (1616 Backman KA: Urinary flow during micturition in normal women. Acta Chir Scand. 1965; 130: 357-70.,1717 Haylen BT, Ashby D, Sutherst JR, Frazer MI, West CR: Maximum and average urine flow rates in normal male and female populations--the Liverpool nomograms. Br J Urol. 1989; 64: 30-8.). A CONV study comparing voiding measurements in women at bladder volumes close to modal Vvoid from frequency/volume charts with Vvoid at maximum cystometric capacity showed that Qmax was lower at the smaller volume, whilst pdetQmax was the same for both volumes (1818 Groen J, van Mastrigt R, Bosch R: Factors causing differences in voiding parameters between conventional and ambulatory urodynamics. Urol Res. 2000; 28: 128-31.). Our study showed no statistical difference in Vvoid between CONV and AMB. Additionally comparison of the average Vvoid on CONV (390 mL) and that from AMB (330 mL) on the Liverpool nomogram would predict that Qmax would be 9% higher during CONV (1717 Haylen BT, Ashby D, Sutherst JR, Frazer MI, West CR: Maximum and average urine flow rates in normal male and female populations--the Liverpool nomograms. Br J Urol. 1989; 64: 30-8.). From this background it seems unlikely that the trend to lower Vvoid during AMB was a factor in the observed higher values for Qmax resulted. Moreover, Groutz et al. found higher Qmax in symptomatic women (mainly patients with urinary incontinence) with voided volumes over 400 mL (1313 Groutz A, Blaivas JG, Sassone AM: Detrusor pressure uroflowmetry studies in women: effect of a 7Fr transurethral catheter. J Urol. 2000; 164: 109-14.). It therefore appears unlikely that lower values of maximum flow rate in CONV might be explained by bladder overdistension as stated by other authors (77 Vereecken RL, Van Nuland T: Detrusor pressure in ambulatory versus standard urodynamics. Neurourol Urodyn. 1998; 17: 129-33.).
Bladder mechanical power is directly proportional to detrusor pressure and urinary flow. During micturition, bladder detrusor does not generate a specific pressure or flow, but rather provides mechanical power. Bladder outflow resistance determines how such power is divided into pressure and flow (1919 Schäfer W: Principles and clinical application of advanced urodynamic analysis of voiding function. Urol Clin North Am. 1990; 17: 553-66.). Our results showing on average no differences for pdetmax and pdetQmax between CONV and AMB and higher Qmax in AMB are consistent of stronger bladder contractions during AMB. However the presence of both 4Fr and 10Fr catheters during CONV may have been responsible for lower Qmax, by reducing urethral cross sectional area although if this was the case a compensatory increase in voiding pressure would be expected.
Considering the sample size and the standard deviations with CONV and AMB of the not significant results pdetQmax, pdetmax and Vvoid, this study had an 80% statistical power to detect a difference between means of 11 cmH2O for pdetQmax, 15 cmH2O for pdetmax and 99 mL for Vvoid, with a significance level (alpha) of 0.05 (two-tailed).
Comparison between our measurements and those described in previous studies using different recording devices in different patient groups is shown in Table-3. Using an older generation device pdetmax measurements were found to be higher from AMB in three previous studies from our institution concerning men with bladder outlet obstruction (22 Webb RJ, Griffiths CJ, Zachariah KK, Neal DE: Filling and voiding pressures measured by ambulatory monitoring and conventional studies during natural and artificial bladder filling. J Urol. 1991; 146: 815-8.,44 Robertson AS, Griffiths C, Neal DE: Conventional urodynamics and ambulatory monitoring in the definition and management of bladder outflow obstruction. J Urol. 1996; 155: 506-11.) and uncomplaining women (33 Heslington K, Hilton P: Ambulatory monitoring and conventional cystometry in asymptomatic female volunteers. Br J Obstet Gynaecol. 1996; 103: 434-41.). Our results showing no difference in detrusor pressure measurements are consistent with a later study which also used an AMB device with integrated flow rate recording but in men with equivocal obstruction on CONV (55 Rosario DJ, MacDiarmid SA, Radley SC, Chapple CR: A comparison of ambulatory and conventional urodynamic studies in men with borderline outlet obstruction. BJU Int. 1999; 83: 400-9.). Considering the very low rate of occurrence of after contractions in our study, we have no evidence to support the speculation voiced by Heslington et al. that the higher values of pdet during voiding measured by older devices were due to misinterpretation of the commonly observed after-contractions in the absence of synchronized flow recording (33 Heslington K, Hilton P: Ambulatory monitoring and conventional cystometry in asymptomatic female volunteers. Br J Obstet Gynaecol. 1996; 103: 434-41.). However it should be noted that Rosario et al. found significant more after-contractions on AMB than on CONV and pressure rises of the after-contractions on AMB were higher than pdetmax of the same patients (55 Rosario DJ, MacDiarmid SA, Radley SC, Chapple CR: A comparison of ambulatory and conventional urodynamic studies in men with borderline outlet obstruction. BJU Int. 1999; 83: 400-9.).
Findings from theses regarding differences in Qmax were inconsistent, with two studies finding higher values from AMB (22 Webb RJ, Griffiths CJ, Zachariah KK, Neal DE: Filling and voiding pressures measured by ambulatory monitoring and conventional studies during natural and artificial bladder filling. J Urol. 1991; 146: 815-8.,55 Rosario DJ, MacDiarmid SA, Radley SC, Chapple CR: A comparison of ambulatory and conventional urodynamic studies in men with borderline outlet obstruction. BJU Int. 1999; 83: 400-9.), and one study no difference (44 Robertson AS, Griffiths C, Neal DE: Conventional urodynamics and ambulatory monitoring in the definition and management of bladder outflow obstruction. J Urol. 1996; 155: 506-11.). It should be noted that the tested population for these studies was men with suspected outlet obstruction. The different patient group and consequent overall higher flow rates in our study makes comparison difficult although it is noted that the trend in all studies is toward higher Qmax measurements from AMB.
Differences in Vvoid again showed a consistent trend towards lower values
in AMB reflecting the known difference between voided volumes found on a voiding
diary and maximum cystometric capacity on CONV with non-physiological filling (33 Heslington K, Hilton P: Ambulatory monitoring and conventional
cystometry in asymptomatic female volunteers. Br J Obstet Gynaecol. 1996; 103:
434-41.
4 Robertson AS, Griffiths C, Neal DE: Conventional urodynamics and
ambulatory monitoring in the definition and management of bladder outflow
obstruction. J Urol. 1996; 155: 506-11.-55 Rosario DJ, MacDiarmid SA, Radley SC, Chapple CR: A comparison of
ambulatory and conventional urodynamic studies in men with borderline outlet
obstruction. BJU Int. 1999; 83: 400-9.). The
lack of a statistically significant difference in our study and that from Webb et
al. (22 Webb RJ, Griffiths CJ, Zachariah KK, Neal DE: Filling and voiding
pressures measured by ambulatory monitoring and conventional studies during
natural and artificial bladder filling. J Urol. 1991; 146:
815-8.) may represent a change in AMB
technique with better encouragement of fluid intake.
CONCLUSIONS
Although this was a retrospective study with the associated methodological limitations the findings are of value since they provide previously undocumented comparative intra-individual voiding data between CONV and AMB for the patient group who most commonly require both investigations as part of their diagnostic assessment. We have confirmed that current AMB devices which allow real-time quality control and synchronous uroflowmetry provide reliable pressure measurement. Clinicians should however be aware that measurements from AMB recordings give higher values of Qmax but similar values for pdetQmax which may partly reflect an overall lower catheter caliber, physiological filling but perhaps also the more ‘normal’ voiding conditions. A prospective study that controls urethral catheters calibre and voided volume is required to clarify the effect of bladder filling rates on voiding parameters among these patients.
REFERENCES
-
1van Waalwijk van Doorn E, Anders K, Khullar V, Kulseng-Hanssen S, Pesce F, Robertson A, et al.: Standardisation of ambulatory urodynamic monitoring: Report of the Standardisation Sub-Committee of the International Continence Society for Ambulatory Urodynamic Studies. Neurourol Urodyn. 2000; 19: 113-25.
-
2Webb RJ, Griffiths CJ, Zachariah KK, Neal DE: Filling and voiding pressures measured by ambulatory monitoring and conventional studies during natural and artificial bladder filling. J Urol. 1991; 146: 815-8.
-
3Heslington K, Hilton P: Ambulatory monitoring and conventional cystometry in asymptomatic female volunteers. Br J Obstet Gynaecol. 1996; 103: 434-41.
-
4Robertson AS, Griffiths C, Neal DE: Conventional urodynamics and ambulatory monitoring in the definition and management of bladder outflow obstruction. J Urol. 1996; 155: 506-11.
-
5Rosario DJ, MacDiarmid SA, Radley SC, Chapple CR: A comparison of ambulatory and conventional urodynamic studies in men with borderline outlet obstruction. BJU Int. 1999; 83: 400-9.
-
6Webb RJ, Griffiths CJ, Ramsden PD, Neal DE: Measurement of voiding pressures on ambulatory monitoring: comparison with conventional cystometry. Br J Urol. 1990; 65: 152-4.
-
7Vereecken RL, Van Nuland T: Detrusor pressure in ambulatory versus standard urodynamics. Neurourol Urodyn. 1998; 17: 129-33.
-
8Schäfer W, Abrams P, Liao L, Mattiasson A, Pesce F, Spangberg A, et al.: Good urodynamic practices: uroflowmetry, filling cystometry, and pressure-flow studies. Neurourol Urodyn. 2002; 21: 261-74.
-
9Abrams P: Bladder outlet obstruction index, bladder contractility index and bladder voiding efficiency: three simple indices to define bladder voiding function. BJU Int. 1999; 84: 14-5.
-
10Cho SY, Yi JS, Park JH, Jeong MS, Oh SJ: Detrusor after-contraction is associated with bladder outlet obstruction. Neurourol Urodyn. 2011; 30: 1361-5.
-
11Bland JM, Altman DG: Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986; 1: 307-10.
-
12Baseman AG, Baseman JG, Zimmern PE, Lemack GE: Effect of 6F urethral catheterization on urinary flow rates during repeated pressure-flow studies in healthy female volunteers. Urology. 2002; 59: 843-6.
-
13Groutz A, Blaivas JG, Sassone AM: Detrusor pressure uroflowmetry studies in women: effect of a 7Fr transurethral catheter. J Urol. 2000; 164: 109-14.
-
14Scaldazza CV, Morosetti C: Effect of different sized transurethral catheters on pressure-flow studies in women with lower urinary tract symptoms. Urol Int. 2005; 75: 21-5.
-
15Costantini E, Mearini L, Biscotto S, Giannantoni A, Bini V, Porena M: Impact of different sized catheters on pressure-flow studies in women with lower urinary tract symptoms. Neurourol Urodyn. 2005; 24: 106-10.
-
16Backman KA: Urinary flow during micturition in normal women. Acta Chir Scand. 1965; 130: 357-70.
-
17Haylen BT, Ashby D, Sutherst JR, Frazer MI, West CR: Maximum and average urine flow rates in normal male and female populations--the Liverpool nomograms. Br J Urol. 1989; 64: 30-8.
-
18Groen J, van Mastrigt R, Bosch R: Factors causing differences in voiding parameters between conventional and ambulatory urodynamics. Urol Res. 2000; 28: 128-31.
-
19Schäfer W: Principles and clinical application of advanced urodynamic analysis of voiding function. Urol Clin North Am. 1990; 17: 553-66.
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ABBREVIATIONS
AMB = Ambulatory urodynamic monitoringCONV = Conventional cystometrypves = Intravesical pressurepabd = Abdominal pressurepdet = Detrusor pressurepdetQmax = Detrusor pressure at maximum flow rateQmax = Maximum flow ratepdetmax= Maximum detrusor pressureVvoid = Voided volumeUR = Urethral resistanceBOOI = Bladder outlet obstruction indexBCI = Bladder contractility index
Publication Dates
-
Publication in this collection
Dec 2014
History
-
Received
01 Jan 2013 -
Accepted
09 Nov 2013