A comparison of ambulatory and conventional urodynamic studies in men with borderline outlet obstruction

What is a representative voiding pattern in children with lower urinary tract symptoms? Lack of consistent findings in ambulatory and conventional urodynamic tests

BACKGROUND

Conventional urodynamics (CU) is a highly standardized evaluation of lower urinary tract function. However, in pediatric patients there is concern that the reliability of measurements could be influenced by development effects and measurement variability, as well as by the unfamiliar clinical environment. Ambulatory urodynamics (AU) provides an alternative to this - it uses natural filling, is measured over a prolonged period, and is conducted in a child-friendly environment.

OBJECTIVE

The aim of this study was to conduct a comparative analysis of AU and CU to evaluate the consistency in voiding patterns obtained with these two methods of urodynamic testing.

STUDY DESIGN

Urodynamic parameters obtained by AU and CU methods in 50 pediatric patients aged >5 years were retrospectively analyzed. Voiding patterns were categorized into six types: coordinated contraction, detrusor after-contraction, fluctuated contraction, pre-void contraction, relief voiding, and weak or absent contraction. Voiding patterns were used to determine the repeatability within urodynamic tests and to identify consistency between AU and CU tests. Five urodynamic parameters were quantified and compared between AU and CU: voided volume, flow rate, maximum detrusor pressure, and detrusor pressure at peak flow rate. For inter-observer variation analysis, 100 voiding curves were randomly selected and categorized by two independent observers; inter-observer agreement was evaluated using the kappa statistic.

RESULTS

A single pattern of voiding was identified in five patients using AU and 37 using CU. Consistency of a single pattern between AU and CU was identified in three patients, and consistency between a predominant pattern with AU, defined by one type of voiding occurring >50% of one's voids, and a single pattern with CU was identified in 10 patients (summary table). Flow rates were similar between methods; however, higher maximum detrusor pressure and detrusor pressure at peak flow and lower voided volume were recorded with AU.

DISCUSSION

AU resulted in more diverse voiding patterns. Along with the differences in measured urodynamic parameters challenges the application of findings from one method to form a clinical diagnosis. Furthermore, CU may not be as sensitive as AU to the variability in lower urinary tract pathophysiology.

CONCLUSIONS

More diverse voiding patterns were identified in AU compared with CU, with a lack of consistency in identified voiding pattern in both methods. Therefore, the urodynamic findings in children may have to be analyzed in more detail, taking the variations into account.

Differences in urodynamic voiding variables recorded by conventional cystometry and ambulatory monitoring in symptomatic women

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.

Pelvic ultrasound evaluation for benign prostatic hyperplasia: prediction of obstruction

Global improvements in water quality, management of infectious diseases, and other medical therapeutics have resulted in a growing population of healthy aging men. One obligate anatomic consequence of aging for these men is the development of benign prostatic hyperplasia (BPH) with secondary bladder outlet obstruction. Although the voiding symptoms associated with the change in bladder health over time predominantly impact the quality of a man's daily experience, there are also significant medical consequences of BPH that require intervention. It is a challenge to distinguish men who are at risk for these medical consequences from the much larger population of older men with voiding symptoms (lower urinary tract symptoms, LUTS). A variety of national guidelines have been developed to establish a diagnostic paradigm for meeting this challenge, but all suffer from inadequate sensitivity for the early identification of men at risk for permanent bladder injury. It is likely that the application of a thorough pelvic ultrasound designed to identify the pertinent anatomic aspects of both the bladder and prostate will improve the sensitivity of these diagnostic paradigms, with subsequent improvement in the outcomes for men with BPH/LUTS.

Availability of a newly devised ambulatory urodynamics monitoring system based on personal device assistance in patients with spinal cord injury

Conventional urodynamics systems have been widely used for the assessment of bladder functions. However, they have some drawbacks due to the unfamiliar circumstances for the patient, restrictive position during the test, expense and immovability of the instrument as well as the unphysiological filling of the bladder. To mitigate these problems, we developed a fully ambulatory urodynamics monitoring system, which enables the abdominal pressure to be measured in a non-invasive manner, as well as the manual recording of various events such as the bladder sensations or leakage of urine. Conventional (CMG) and furosemide-stimulated filling cystometry (FCMG) were performed for 28 patients with neurogenic bladders caused by spinal cord injury (24 males and 4 females, age: 49.4 ± 13.9 years, BMI: 23.5 ± 2.4). There were high correlation coefficients (r=0.97 ± 0.02) between the clinical parameters measured by the conventional rectal catheter and those measured by our non-invasive algorithm in the FCMG studies. Also, 10 of the patients (36%) were diagnosed as having different reflexibility of the bladder between conventional CMG and FCMG (p<0.05). In the patients with detrusor overactivity, the average volume and detrusor pressure at bladder sensation in FCMG were lower than those in CMG, while the average compliance was higher (p<0.05). In the patients with areflexic bladders, the number of patients with detrusor overactivity was higher in FCMG and leakage was observed more frequently. These results showed that our system could be a useful additional tool in the clinical assessment of patients in which conventional cystometry failed to explain their symptoms.

Twenty-four-hour ambulatory urodynamics in healthy young men

OBJECTIVE

To describe normal natural fill urodynamics in young men during normal and increased fluid intake.

MATERIAL AND METHODS

Thirty healthy males aged 21-32 years volunteered for an ambulatory urodynamic 24 h investigation with a suprapubic catheter. The recorded micturition data were: frequency (f), voided volume (VV), voiding time, maximal flow rate (Qmax) and time to Qmax. The number of sensed and not-sensed bladder contractions, duration and time in relation to voiding were also recorded. During the recording day subjects were randomized to normal (30 ml/kg body weight per day) or larger (60 ml/kg body weight per day) fluid intake.

RESULTS

As expected there was a larger urine production and an increased voiding frequency in the fluid-loaded group (p<0.0001). The detrusor pressure (Pdet) Qmax was significantly higher in the fluid-loaded group (73 cmH2O, range 57-94) than in the normal fluid intake group (60 cmH2O, range 45-86) (p=0.003). No other urodynamic data differed significantly between the two groups. When comparing the ambulatory urodynamic data with previously obtained home flowmetry recordings from the same volunteers differences were only found in voiding frequency. The majority of participants had detrusor contractions, felt and unfelt, during the filling phase. Three types of detrusor activity during voiding phase could be described: type 1, with one micturition contraction, type 2, with several small contractions before micturition, and type 3, with large prolonged contractions leading to micturition.

CONCLUSIONS

Ambulatory urodynamics in normal young men showed a large interindividual variation. Bladder contractions during filling were frequently recorded, and premicturition contractions were consistently found. The data found in this study were similar to previous home flow recordings in the same group.

Clinical usefulness of ambulatory urodynamics in the diagnosis and treatment of lower urinary tract dysfunction

OBJECTIVE

Ambulatory urodynamics is reported to be useful for the detection of detrusor overactivity. However, the procedure is time-consuming, technically challenging and expensive. Its clinical usefulness for the detection and treatment of bladder dysfunction has not been studied in detail.

MATERIAL AND METHODS

Twenty-five patients (17 men, eight women, median age 59 years) with lower urinary tract symptoms underwent ambulatory urodynamic examination.

RESULTS

In six out of 25 patients (24%), ambulatory urodynamics was not evaluable. Where the procedure was technically feasible, diagnosis was possible in 72%. Treatment was modified in 63%, leading to satisfactory results in 42% of the patients.

CONCLUSIONS

Ambulatory urodynamics is the most sensitive tool for the detection or exclusion of detrusor overactivity. Therefore, the method is valuable when all other diagnostic means have failed to detect the underlying lower urinary tract dysfunction. In these cases, treatment decisions can safely be based on the results of ambulatory urodynamics.

Are conventional pressure-flow measurements dependent upon filled volume?

OBJECTIVE

To determine, in a prospective study, whether detrusor pressure (p(det.Qmax)) and maximum urinary flow rate (Q(max)) measurements obtained after filling to maximum cystometric capacity (MCC) differ from those obtained with filling restricted to average voided volume (V(void)), as standard protocols for pressure flow studies (PFS) mandate bladder filling until the subject has a strong desire to void, which aids standardization but further divorces the test from real-life experience.

PATIENTS AND METHODS

After calculating the appropriate sample size, 84 patients attending for PFS with an adequately completed 3-day frequency-volume chart were recruited. Each underwent two consecutive PFS with filling to MCC and average V(void) in a random order, and measurements of p(det.Qmax) and Q(max) were compared. For men, the agreement for a diagnosis of obstruction between the tests was also assessed.

RESULTS

Complete data were obtained from 76 (90%) of the patients, with a mean (range) age of 64 (20-94) years. The mean (sd) difference between MCC and average V(void) was 134 (113) mL (P < 0.01). There were no significant differences between estimates of Q(max), at - 0.1 (3) mL/s (P = 0.75), and of p(det.Qmax), at - 1 (13) cmH(2)O (P = 0.91), obtained within each patient. For men there was 91% agreement (32 of 35) in the classification of obstruction.

CONCLUSIONS

Restriction of filling to the average V(void) during PFS allows a closer approximation to normal voiding and results in no clinically relevant change to the value of standard pressure-flow measurements or alters individual classification of obstruction.

Overactive bladder in men: special considerations for evaluation and management

Lower urinary tract symptoms (LUTS) in men may arise from a variety of underlying causes, including benign prostatic hyperplasia. LUTS may have a significant component of storage symptoms (urgency, frequency, urge incontinence) at presentation; however, the absence of overactive bladder (OAB) symptoms does not necessarily imply pure outlet obstruction nor does their presence indicate the lack thereof. Symptomatic correlates to urodynamic findings are high when considering isolated OAB symptoms. However, mixed presentations or more overtly obstructive scenarios have less correlation with baseline symptom appraisal instruments. The ideal approach for diagnosis and management is predicated on a graded approach, with more invasive evaluation withheld for those men in whom presumptive therapy fails or who present with associated complex symptoms and in whom a higher level of intervention is being considered. The increasing incidence of LUTS with age implies a partial detrusor contribution, which must be considered in the overall management schema.

Urodynamic patterns of normal male micturition: influence of water consumption on urine production and detrusor function

PURPOSE

Urodynamic characterization of normal male micturition can be a useful standard in the analysis of data on patients complaining of voiding dysfunction. The validity of such a standard is based on the need to obtain baseline parameters of pressure flow values, an important consideration when evaluating prostatic obstruction and its treatment. While current numerical pressure flow values provide a useful summary of the voiding sequence, a more complete analysis of the pattern of normal voiding may reveal more functionally useful information concerning micturition. We establish basic experimental conditions that simulate normal voiding of physiologically produced urine by the kidneys measured at intervals representing real stages of bladder filling. We report the results of an investigation designed to study consecutive micturitions at bladder volumes determined by water consumption and endogenous circadian rhythm. Our particular focus is to examine critically the urodynamic pattern of pressure flow and obtain evidence to support the hypothesis that fluid consumption has an important role in detrusor function.

MATERIALS AND METHODS

Urodynamic studies were conducted on 39 asymptomatic male volunteers with a mean age of 25.8 years (range 21 to 31) and mean weight of 75.5 kg. (range 63 to 95). Volunteers were divided into 2 groups according to water consumption regimen of 30 ml./kg. daily (17 patients, group 1) and 60 ml./kg. daily (12, group 2). Bladder pressure was monitored via a suprapubic catheter and abdominal pressure was measured via a rectal balloon using an ambulatory system. Average duration of each monitoring period was 20.5 hours. Detrusor pressure and flow rate records from each subject were identified, and consecutive filling and voiding phases were averaged during the entire monitoring period using the onset of micturition as a time marker. The average pattern of pressure, flow rate, cumulative volume and contractility curves for each subject, as well each for group, was computed and graphically presented. For each group the average parameters of urethral opening pressure, maximum detrusor pressure, detrusor pressure at maximum flow rate, bladder capacity and bladder contraction strength were calculated and compared statistically. Numerical values are mean +/- SE.

RESULTS

Water consumption and urine production rate influenced the pattern and many of the urodynamic parameters of micturition. In both groups there was a detrusor pressure increase before voiding and numerically maximum detrusor pressure consistently occurred before micturition started. Micturition pattern showed an asymptotic relationship between pressure and flow. Doubling of water consumption increased urethral opening pressure from 51.2 +/- 3.2 to 61.5 +/- 5.1 (p <0.05), maximum detrusor pressure from 58.9 +/- 4.5 to 70.0 +/- 6.2 cm. H(2)O (p <0.01) and contractility from 15.4 +/- 1.4 to 17.7 +/- 1.4 w/m(2). There were no significant differences due to water consumption in maximum flow rate (24.4 +/- 1.4 to 25.2 +/- 1.8 ml. per second) or bladder capacity (286 +/- 20 to 329 +/- 15 ml.) but a significant increase in the number of micturitions from 5.8 +/- 0.5 to 9.8 +/- 0.5 per day (p <0.001) proportional to water consumption.

CONCLUSIONS

The configuration of the observed pressure flow characteristics of the normal male is suggestive of the "Starlings law" relationship and the pattern of the urodynamic parameters were markedly different from those reported in the current standardization literature, suggesting the need to revise the current concept of normal male micturition. Voiding pressure and contractility increased in accordance with water consumption and urine production.