Measurement of voiding pressures on ambulatory monitoring: comparison with conventional cystometry

A series of 20 patients underwent conventional medium fill cystometry (CMG) and ambulatory monitoring during natural bladder filling (AM). The measurement of voiding pressures by the 2 techniques was compared. The maximum subtracted detrusor contraction pressure recorded during CMG (50 +/- 30 cm H2O) was significantly less than that recorded during AM (86 +/- 35 cm H2O). Voiding pressures during natural filling are greater than those observed during conventional urodynamic studies: this finding may have important implications in the definition of bladder outflow obstruction.     

Long-term monitoring of bladder pressure in chronic retention of urine: the relationship between detrusor activity and upper tract dilatation

We investigated 41 men with chronic retention of urine owing to bladder outflow obstruction by long-term monitoring of bladder pressure and conventional cystometry to determine the relationship between detrusor pressure and upper tract dilatation. We confirmed that high pressures during conventional filling cystometry were common in men with upper tract dilatation. However, important differences were demonstrated between long-term monitoring and conventional cystometry. The pressure increase during the natural filling phase of long-term monitoring was significantly smaller than that during conventional cystometry. Detrusor instability was found in 88 per cent of the men during long-term monitoring but in only 51 per cent during conventional cystometry (p less than 0.001). High frequency unstable detrusor contractions during long-term bladder pressure monitoring were associated significantly with upper tract dilatation (p less than 0.0001) and correlated significantly with impairment of glomerular filtration rate (rs equals -0.7339, p less than 0.001).     

The outcome of prostatectomy on chronic retention of urine

A total of 68 men with bladder outflow obstruction and chronic retention (residual urine greater than 300 ml.) underwent investigation before and after prostatectomy with medium fill cystometry and natural fill long-term bladder pressure monitoring. Postoperatively, upper tract dilatation (present in 28 men preoperatively) resolved in all but 2 men and serum creatinine levels improved significantly. Irritative and obstructive symptom scores improved postoperatively (p less than 0.00006), although 17% of the men still had significant symptoms. Residual urine volumes decreased and flow rates improved (p less than 0.00006) but 32% of the men still had a residual urine of greater than 200 ml. Urodynamic parameters improved during medium fill cystometry and long-term monitoring. The main risk factors for upper tract dilatation are a pressure increase during bladder filling on conventional cystometry and the frequency of phasic detrusor activity during long-term monitoring, and they decreased postoperatively.     

Ambulatory monitoring of bladder pressure in low compliance neurogenic bladder dysfunction.

Upper tract dilatation is an important complication of neurogenic bladder dysfunction. Risk factors include incomplete bladder emptying with large residual volumes of urine and high tonic increases in bladder pressures during artificial filling. However, on natural bladder filling many of these patients do not have high tonic increases in detrusor pressures. We compared conventional urodynamic studies with ambulatory monitoring during natural bladder filling in 66 patients with low compliance neurogenic bladder dysfunction. There were marked differences in the tonic increase in bladder pressure during filling and in compliance during artificial bladder filling compared with ambulatory monitoring. Faster filling rates during artificial filling resulted in greater end filling pressures and lower compliance but the lowest increases in bladder pressure were found during ambulatory monitoring with natural bladder filling. During natural bladder filling significantly more patients had phasic changes in detrusor pressure; a high intensity of phasic activity during ambulatory monitoring correlated with high end filling pressures during artificial bladder filling. Upper tract dilatation was associated with large volumes of residual urine, high resting bladder pressures and low bladder compliance on filling at 100 ml. per minute. However, upper tract dilatation was most strongly associated with high intensity phasic pressure activity during natural bladder filling in combination with high residual urine volumes and high resting bladder pressures. On multivariate statistical analysis the intensity of phasic pressure activity during ambulatory monitoring was the best discriminator between patients with dilated and normal upper tracts. Our study has highlighted important differences in the results obtained by artificial filling cystometry and ambulatory monitoring during natural bladder filling. In particular, high increases in pressure did not occur during natural bladder filling, apparently being replaced by phasic activity. Within this group of patients who had the high risk factor of low bladder compliance measured during artificial bladder filling, a combination of greater residual urine volumes, greater resting pressures and greater phasic activity during natural bladder filling was found in patients with upper tract dilatation.     

Comparison of long-term monitoring and standard cystometry in chronic retention of urine

Twenty-eight men with chronic retention of urine were investigated by means of a standard medium fill cystometrogram and by long-term monitoring of bladder pressure whilst the bladder filled naturally. Effective cystometric capacity was greater in each patient during standard cystometry (297 +/- 180 ml) than during long-term monitoring (99 +/- 100 ml; P less than 0.002). The incidence of detrusor instability was also greater during long-term monitoring than during standard cystometry (P less than 0.01). During filling, the detrusor pressure increased significantly both in standard cystometry (27.9 +/- 22.8 cmH2O; P less than 0.002) and in long-term monitoring (4.9 +/- 6.5 cmH2O; P less than 0.002). The detrusor pressure rise during filling was significantly greater during the standard cystometrogram than during long-term monitoring (P less than 0.002). Even when the detrusor pressure rise was corrected to take account of the different cystometric capacities this difference persisted (P less than 0.05). High end filling pressures are common in men with chronic retention investigated by means of a standard cystometrogram but are not observed during long-term monitoring. Such high pressures are probably due to the unphysiological rates of filling and the large volumes of fluid instilled during standard cystometry.     

Radiotelemetered cystometry in pigs: validation and comparison of natural filling versus diuresis cystometry

PURPOSE: Cystometry has previously been performed in awake animals using vesical and abdominal catheters, and artificial bladder filling. Conventional urodynamic recordings may be obtained in this manner, albeit under nonphysiological and potentially stressful conditions. Therefore, we developed a technique to perform continuous, ambulatory cystometric monitoring in pigs. MATERIALS AND METHODS: A dual pressure radiotelemetry device was surgically implanted in 22 large white pigs. Vesical and abdominal pressures were recorded and validated, subtracted detrusor pressures were derived and natural fill and diuresis cystometry was compared. RESULTS: Continuous recordings were obtained for 1 to 24 hours, and the devices remained in the animals for up to 3 months. There were few complications and incrustation of the intravesical catheter tip occurred but it did not appear to affect recorded pressures. The pressure data were validated by comparison with filling pressures during bladder distention and simultaneous conventional cystometry at the end of the experimental period. Comparison of natural filling and diuresis cystometrograms showed that natural bladder filling results in higher maximum detrusor pressure during voiding (38.1 versus 33.9 cm. H2O, p <0.05), higher detrusor pressure after contractions (42.6 versus 32.2 cm. H2O, p <0.05) and more frequent detection of unstable contractions in pigs with detrusor instability secondary to experimental manipulation of the lower urinary tract (77.8% versus 45.0%, p <0.05). CONCLUSIONS: This technique allows continuous cystometric monitoring in less stressed animals under more physiological conditions for relatively long periods and, thus, allows prolonged assessment of bladder function in pigs in response to pathological and pharmacological manipulations. Nonphysiological rates of bladder filling have been shown to result in detrusor inhibition, which emphasizes the importance of ambulatory cystometry when describing bladder function.     

Ambulatory monitoring of bladder pressures in patients with low compliance as a result of neurogenic bladder dysfunction

A group of 28 patients with neurogenic bladder dysfunction and low bladder compliance was studied using medium fill cystometry (CMG) and ambulatory monitoring (AM) during natural bladder filling. The aims of the study were to compare the 2 techniques and to determine if ambulatory monitoring might be useful in predicting upper tract dilatation. AM demonstrated significantly lower end filling pressures compared with CMG. Phasic detrusor contractions were found more commonly during AM and the frequency of phasic detrusor contractions during AM was associated significantly with poor compliance identified during CMG. Patients with upper tract dilatation had significantly greater residual urine volumes, higher pressure rises during CMG and higher frequencies of phasic detrusor contractions compared with those patients with normal upper tracts. The high pressures seen at the end of a medium fill CMG were not found during AM and therefore are unlikely to be the underlying explanation of upper tract dilatation in such patients.     

Ambulatory urodynamic monitoring of external urethral sphincter behavior in chronic prostatitis patients

Aim: To study the behavior of external urethral sphincter in chronic prostatitis (CP) patient under natural filling.Methods: Twenty-one CP patients and 17 normal volunteers were involved in the study. Both the patients andvolunteers underwent ambulatory urodynamic monitoring (AM) and conventional medium filling cystometry (CMG).Urodec 500 was used for AM and Menuet for CMG. AM findings from CP patients were compared with those fromnormal volunteers, and the results from AM were compared with those from CMG. Results: In AM, the restingand voiding external urethral sphincter (EUS) pressures and maximum urethral closure pressures (MUCP) weresignificantly higher in CP patients [ ( 121.5 ±10.3) and (85.6±3.5) cm water, respectively ] than in normalvolunteers [ (77.6±11.4) and (10.3±1.6) cm water, respectively)]. Conclusion: The behavioral changes ofEUS in CP patients included spasm and instability of EUS, which were demonstrated using AM under natural filling;the findings were also in accord with the res     

Impact of radical prostatectomy on the characteristics of bladder and urethra.

A prospective study was done to evaluate the long-term effects of radical prostatectomy on the function of the bladder in filling and voiding. Preoperative urodynamic studies were done on 29 patients with a mean age of 62.9 +/- 5.2 years. The preoperative results show that 16 of the 29 patients demonstrated detrusor instability with maximum contractile pressures of 59 +/- 28 cm. water. Followup urodynamic assessment was done in 13 of these patients 22.9 +/- 1.1 months after surgery. Postoperatively, the maximum detrusor instability pressure did not decrease significantly (49 +/- 17 cm. water). Comparison of the operative and postoperative urodynamic characteristics of bladder filling shows that radical prostatectomy produced no significant change in the filling characteristics of the bladder in terms of bladder capacity, or volume at which sensations of fullness or urgency are reported. Voiding pressure-flow studies show a significant increase in maximum flow rate (8 +/- 1 to 13 +/- 2 ml., per second, p = 0.007), and significant decreases in maximum detrusor pressure (61 +/- 5.4 to 39 +/- 4 cm. water, p = 0.002), urethral opening pressure (45 +/- 7 to 25 +/- 4 cm. water, p = 0.004) and residual volume (150 +/- 37 to 62 +/- 43 ml., p = 0.019). Urethral profile measurements show that there was no significant change in either the maximum urethral closure pressure (94 +/- 9 to 83 +/- 9 cm. water) or external sphincter length (3.6 +/- 0.8 to 3.2 +/- 0.8 cm.). Preoperatively, the bladder neck pressures were 25 +/- 4.4 cm. water and were abolished after prostatectomy, indicating that the decrease in obstructive characteristics is due to removal of the prostate.     

The effect of medium-fill and slow-fill saline cystometry on detrusor pressure in infants and children with myelodysplasia.

A total of 38 infants and children with myelodysplasia was selected for statistical comparison of the effects of medium-fill and slow-fill saline cystometry on detrusor pressure. Medium-fill cystometry was performed at 20% of estimated bladder capacity per minute (up to 25 cc per minute) and slow-fill cystometry at 2% (up to 2.5 cc per minute). In 26 cases the filling rate did not determine the change in detrusor filling pressure while in 12 the change in detrusor filling pressure was greater than 15 cm. water during medium-fill but not slow-fill cystometry (p = 0.001). In 24 cases the filling rate did not determine the occurrence of maximal detrusor pressure greater than 40 cm. water but in 14 such pressure was noted during medium-fill but not slow-fill cystometry (p = 0.0005). Excluding 10 children with coexisting vesicoureteral reflux, differences in the change of detrusor filling pressure greater than 15 cm. water and maximal detrusor pressure greater than 40 cm. water remained statistically significant (p = 0.01 and p = 0.005, respectively). It is concluded that detrusor pressure can be manipulated by varying bladder filling with saline solution.     

Effect of lumbar-epidural administration of tramadol on lower urinary tract function

AIMS: Intrathecal and epidural administration of micro-agonist opioids is associated with urinary retention, a potentially serious adverse-event. In animal studies tramadol has been found not to affect voiding function. We evaluated urodynamic effects of epidural tramadol in humans. METHODS: Fifteen adults planned for cystoscopy under local-anesthesia underwent urodynamics (UDS) at baseline and 30 min after administration of 100 mg tramadol in lumbar-epidural space. UDS consisted of filling cystometry, pressure-flow study and pelvic floor electromyography (EMG). Subsequently, all underwent cystoscopy and were observed for 6 hr. RESULTS: After injection of tramadol, a significant rise was observed in bladder capacity (391.8 +/- 179.6 ml vs. 432.7 +/- 208.8 ml; P = 0.019) and compliance (60.1 +/- 51.5 ml/cm H(2)O vs. 83.0 +/- 63.0 ml/cm H(2)O; P = 0.011) without a significant change in filling pressure (22.5 +/- 13.2 cm H(2)O vs. 24.1 +/- 15.1 cm H(2)O; P = 0.576). Filling sensations were delayed significantly (P < or = 0.05). EMG during filling phase showed a significant fall (P = 0.027). Peak flow-rate (Q(max)), average flow-rate, postvoid residue and detrusor pressure-at-Q(max) did not show significant change from baseline (P > 0.05). Three patients had bladder outlet obstruction which did not worsen after the injection. Guarding reflex was inhibited in seven out of 12 patients who had it at baseline (P = 0.016). CONCLUSIONS: Epidural tramadol increases the bladder capacity and compliance and delays filling-sensations, without ill effect on voiding. This seems true even for patients with obstructed outflow; however, due to small number of patients a definite conclusion cannot be derived. These results will guide clinician to avoid catheterization in cases where epidural tramadol is used for postoperative pain. The inhibitory effects of tramadol on EMG activity are intriguing and need further studies.     

Ambulatory monitoring of bladder and detrusor pressure during natural filling

We have developed a system to perform fully ambulatory monitoring studies of the bladder. Bladder and rectal pressures are recorded during natural filling of the bladder for up to 6 hours. This system has been evaluated in 19 studies performed on 15 patients. The mean duration of the studies was 3 hours 51 minutes (standard deviation +/- 1 hour 3 minutes) and the mean number of voids per patient was 3.8 +/- 2.2. Visual inspection of the recorded data showed that subtraction of the rectal trace from the bladder trace provided a useful detrusor trace when subjects were ambulant as well as resting. When ambulant, movement caused typical peak-to-peak pressure variability in the bladder and rectal traces of approximately 30 +/- 20 cm. water (mean and standard deviation of peak-to-peak pressure for typical ambulant 5-minute sections for each patient), which after subtraction was reduced on the detrusor trace to 10 +/- 5 cm. water. The equivalent figures when resting were 9 +/- 5 cm. water, subtracting to less than 5 cm. water for the detrusor. Further measurements also were calculated for the whole of each trace. The system provided good quality recordings and should prove useful in future evaluations of natural fill urodynamic studies.     

Ambulatory monitoring and electronic measurement of urinary leakage in the diagnosis of detrusor instability and incontinence

The ability of conventional artificial filling urodynamic studies (CMG) and ambulatory monitoring during natural bladder filling (AM) to detect phasic detrusor activity (detrusor instability) and incontinence was studied in 52 patients suspected on clinical grounds of having bladder dysfunction, but in whom a CMG had not provided an adequate explanation of their symptoms. Detrusor instability (DI) was found on AM in 31 patients who were not unstable on conventional CMG using the criteria of the International Continence Society: DI was diagnosed on filling in 20 patients and on provocation in a further 11. Incontinence was demonstrated by electronic nappy testing in 23 patients: 13 had urge incontinence due to DI, 7 had genuine stress incontinence alone and 3 had both genuine stress incontinence and detrusor instability. Thus DI was diagnosed significantly more frequently by AM than by CMG. Ambulatory monitoring was more sensitive in the diagnosis of instability and incontinence and it may prove to be a valuable aid in the diagnosis of bladder dysfunction not detected during conventional cystometry.     

The male sling for stress urinary incontinence: urodynamic and subjective assessment

PURPOSE: We prospectively examined whether the fixed urethral resistance of the perineal male sling for the treatment of stress incontinence causes significant bladder outlet obstruction or de novo voiding dysfunction. MATERIALS AND METHODS: A total of 22 patients (average age 67 years old) were evaluated before and after surgery with videourodynamics, the self-administered UCLA Prostate Cancer Index incontinence section and pad score. RESULTS: Mean followup was 25 months (range 6 to 42). All patients complained of a moderate to severe problem before surgery. After surgery 16 (73%) reported a very small problem/no problem, 3 (14%) a moderate problem and 3 (14%) reported a big problem. Average pad use +/- SD decreased from 4.6 +/- 2.5 to 0.74 +/- 1.0 pads (p <0.01). Median UCLA Prostate Cancer Index incontinence score increased from 82 to 313, p <0.001. Mean retrograde leak point pressure (RLPP) increased from 30.4 +/- 15.9 to 59.9 +/- 9.7 cm water. Bladder outlet obstruction did not develop in any patients after surgery. Average maximum flow rate did not change significantly (17.7 +/- 6.5 vs 19.2 +/- 9.7 ml per second, p = 0.6). Nor was there a significant change in detrusor pressure at maximum flow rate (40.3 +/- 9.2 vs 45.8 +/- 14.7 cm water, p = 0.3). While de novo urgency or urge incontinence did not develop in any patients, 2 of 5 patients with a moderate/big leakage problem demonstrated postoperative detrusor overactivity on cystometry. Both individuals requiring more than 3 pads daily had a postoperative RLPP of less than 50 cm water. CONCLUSIONS: Pad use, leak point pressure and urinary incontinence scores are significantly improved after sling surgery. Fixed resistance does not lead to bladder outlet obstruction. Postoperative RLPP less than 50 cm water and urodynamic detrusor overactivity are associated with increased pad use and bother.     

Bladder filling by autologous urine production during cystometry: a urodynamic pitfall!

AIMS: The rate of autologous urine production should not have a major disturbing influence on cystometric urodynamic parameters such as first filling sensation, normal desire to void, strong desire to void, and cystometric bladder capacity. Instructions to patients and drinking behavior can have considerable impact, especially if filling cystometry is preceded by free uroflowmetry. We studied the influence of autologous urine production during filling cystometry on total bladder volume. METHODS: Urodynamic investigations performed between September of 2000 and February of 2001 were analyzed. Only those urodynamic investigations for which total bladder capacity could be calculated were taken into account (i.e., catheterization before and after cystometry and no urine loss during the investigations). RESULTS: After screening, 186 investigations were used for further analysis. Mean filled volume (external infusion plus autologous urine production) was 346 +/- 152 mL, but mean real bladder capacity (i.e., voided volume + residual urine) was 391 +/- 170 mL. In all patients, 14% extra urine was produced due to autologous urine production (mean filling rate, 6.1 mL/min). In 42% of the investigations, the real bladder capacity was more than 110% of the infused volume. In 18% of the patients, the contribution of natural bladder filling was more than 25% of the infused volume. CONCLUSIONS: Natural bladder filling plays a substantial role during filling cystometry and has a disturbing influence on calculated urodynamic parameters. Attention should be paid to patient instructions before the urodynamic investigation. The combination of free uroflowmetry followed by filling cystometry should be avoided. This avoidance is especially important if interventional studies are performed. Careful interpretation of studies depending on bladder capacity parameters is mandatory, and such parameters should be corrected for autologous bladder filling.     

Effects of catheter size on urodynamic measurements in men undergoing elective prostatectomy

Thirty men undergoing prostatectomy for symptoms of bladder outflow obstruction and low measured maximum flow rates (20 before and 10 after operation) were studied by means of urodynamic investigation. Paired studies were performed on each patient using a large catheter assembly (4 and 10 F) and a small catheter assembly (epidural line, outside diameter 1.1 mm). The order in which the studies were performed was varied randomly. Detrusor pressure at maximum flow rate was significantly greater in the large catheter study (73 +/- 30 cm H2O) than in the small catheter study (65 +/- 27 cm H2O; P less than 0.003). The maximum flow rate was significantly smaller in the large catheter study (8.9 +/- 9.5 ml/s) than in the small catheter study (12 +/- 7 ml/s; P less than 0.001). The increase in detrusor pressure at maximum flow that was noted during the large catheter study was confirmed in the 20 men who were studied before prostatectomy (mean increase 11 +/- 11 cm H2O; P less than 0.001) but no difference was found between the two methods in the 10 men studied after prostatectomy (50 +/- 19 cm H2O and 49 +/- 15 cm H2O). Using a large catheter assembly to perform urodynamic investigations has the advantage that repeated studies can be performed without recatheterisation, but it has the disadvantage of producing a small increase in detrusor pressure at maximum flow in men with symptoms of bladder outflow obstruction. Few errors in diagnosis should result, however, if laboratories using such catheters are aware of this effect and establish their own limit of normal for voiding pressures.     

Bladder cooling reflex in patients with multiple sclerosis

PURPOSE: We describe the effect of intravesical ice water instillation in patients with multiple sclerosis and without an overactive bladder. MATERIALS AND METHODS: Of 131 consecutive patients with multiple sclerosis who presented with a urinary disorder we selected for study 10 men and 29 women with a mean age plus or minus standard deviation of 50 +/- 9 years who had multiple sclerosis without an overactive bladder. Nonoveractive bladder was defined as no involuntary detrusor contraction up to 400 ml. of maximum fill on routine cystometry. We performed cystometry with saline at 25 to 30C at an infusion rate of 50 and 100 ml. per minute, and with ice water at 0 to 4C at a rate of 100 ml. per minute. Ice water cystometry was considered positive when an involuntary detrusor contraction occurred before 200, and between 200 and 400 ml. of filling. Ice water cystometry was considered negative when there was no involuntary detrusor contraction during ice water filling up to 400 ml. RESULTS: Ice water cystometry enabled us to elicit involuntary detrusor contractions in 21 patients, which remained undetected by warm water cystometry at rates of 50 and 100 ml. per minute. The test was positive before 200, and between 200 and 400 ml. in 10 and 11 cases, respectively. Positive ice water cystometry was significantly associated with irritative signs or significant post-void residual urine volume. CONCLUSIONS: An involuntary detrusor contraction was not elicited by cystometry at 50 or 100 ml. per minute, implying that the afferent mechanoreceptor reflex limb via ADelta fibers is not involved. In contrast, ice water cystometry at 100 ml. per minute elicited an involuntary detrusor contraction, suggesting involvement of an afferent reflex limb via capsaicin sensitive C fibers. These involuntary detrusor contractions revealed by ice water cystometry are probably relevant to an overactive bladder. In urinary disorders such a positive test indicates a spinal lesion. In multiple sclerosis it may have pathophysiological value, indicating a spinal rather than cerebral mechanism of overactive bladder, and diagnostic value, indicating multifocal demyelination.     

Is detrusor instability in elderly males related to the grade of obstruction?

Analysis of 185 consecutive patients with BPH revealed concomitant detrusor instability in 20% of the patients. Of all patients 30.9% were not obstructed, 51.8% were moderately obstructed and 17.3% were severely obstructed. Patients with detrusor instability during filling cystometry revealed no differences in average age, prostate volume or symptoms. Mean filling cystometry parameters revealed earlier sense of urge correlating with higher pressures at lower volumes in patients with detrusor instability. Pressure-flow analysis showed no differences between the patients with and without detrusor instability in bladder outflow obstruction parameters. Further analysis, however, revealed that the prevalence of patients with detrusor instability reaches a “steady state” at a moderate level of obstruction. On clinical epidemiological grounds, the conclusion is made that detrusor instability is developing in the early phase of obstruction. Probably detrusor instability and bladder outflow obstruction are concomitant, due to the aging process in many of these patients. © 1995 Wiley-Liss, Inc.