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Bladder Pressure (bladder + pressure)
Selected AbstractsPhosphodiesterase-linked inhibition of nonmicturition activity in the isolated bladderBJU INTERNATIONAL, Issue 9 2004J.I. Gillespie Over the past few months Gillespie has published several papers in the BJU International investigating the overactive bladder and BOO, using novel models and theories. This next paper continues these concepts and shows that the mechanisms influencing the frequency of agonist-induced phasic activity in the isolated bladder model is slowed by cAMP. These findings will have important implications in future pharmacological strategies in the overactive bladder. OBJECTIVE To explore the influence of intracellular cAMP on phasic activity in the isolated bladder (phasic rises in intravesical pressure associated with waves of contraction and local stretches that can be activated by muscarinic or nicotinic agonists), as it has been argued that this activity underlies nonmicturition contractions, and that it contributes to the generation and modulation of afferent nerve activity. MATERIALS AND METHODS Isolated whole bladders from female guinea pigs (270,300 g) were cannulated via the urethra and suspended in a chamber containing oxygenated Tyrode solution at 33,35 °C. Bladder pressure was recorded and pharmacological agents added to the solution bathing the abluminal surface of the bladder. RESULTS Forskolin (1,3 µmol/L), an activator of adenyl cyclase, reduced the frequency and amplitude of the phasic activity induced by the muscarinic agonist arecaidine (300 nmol/L). There were similar changes in frequency and amplitude in bladders exposed to the nonspecific phosphodiesterase (PDE) inhibitor iso-butyl-methyl-xanthene (IBMX). The actions of specific PDE inhibitors were explored to assess which isoenzymes might be responsible for regulating phasic activity. ENHA (PDE-2), zaprinast (PDE-5, -6, -8, -9 and -11) and siguazodan (PDE-3) had no effect. Zardavarine (PDE-3, -4) and Ro 20-1724 (PDE-4) reduced both the frequency and amplitude of the phasic activity. Nerve-mediated rises in intravesical pressure were also inhibited by Ro 20-1724, and the inhibition was more pronounced at 6.5 Hz than at 30 Hz stimulation. Ro 20-1724 inhibited nerve-mediated fluctuations induced by prolonged (200 s) stimulation at 6.5 Hz. CONCLUSION The mechanisms influencing the frequency of agonist-induced phasic activity in the isolated bladder are slowed by cAMP. Degradation of intracellular cAMP in the cells responsible for phasic activity appears to involve primarily PDE-4. The importance of these observations in relation to the overall physiological regulation of the bladder are discussed, and the possible importance of these findings in the development of pharmacological strategies to modulated bladder activity reviewed. [source] Effect of nicotine on the pelvic afferent nerve activity and bladder pressure in ratsINTERNATIONAL JOURNAL OF UROLOGY, Issue 8 2009Hitoshi Kontani Objectives: To record afferent nerve activity and bladder pressure in anesthetized male rats and to investigate whether increased afferent nerve activity induced by nicotine is able to evoke reflex bladder contractions. Methods: Using continuous infusion cystometrography, bladder pressure was measured via a bladder cannula. Afferent activity was recorded in the uncut L6 dorsal root. Nicotine was injected intra-arterially through a cannula placed near the bifurcation of the internal iliac artery a few minutes after micturition. Results: Nicotine (0.15,1.5 µmol) evoked a marked elevation of afferent discharge without a simultaneous increase in bladder pressure. Bladder contractions appeared about 43 and 19 s after bolus injection of nicotine at 0.45 and 1.5 µmol, respectively. Firing rates of afferent nerves were reduced when the contraction appeared. Continuous infusion of nicotine at 0.75 µmol/min for 20 min evoked marked elevation of afferent discharge, which was maintained during infusion of nicotine and after it had been withdrawn. Repetitive contractions were observed thereafter and disappeared when the L6 dorsal roots were bilaterally resected. Conclusions: A transient increase in afferent discharges induced by bolus injection of nicotine was unable to evoke reflex bladder contraction. Repetitive bladder contractions after withdrawal of continuous nicotine infusion were induced in a reflex manner by the increased afferent activity. [source] Management of Low Compliant Bladder in Spinal Cord Injured PatientsLUTS, Issue 2 2010Won Hee PARK Low bladder compliance means an abnormal volume and pressure relationship, and an incremental rise in bladder pressure during the bladder filling. It is well known that at the time bladder capacity decreases, intravesical pressure increases, and the risk of upper deterioration increases. Hypocompliance is usually thought to be the range from 1.0 to 20.0 mL/cmH2O. Though the exact cause of hypocompliance is not known, it may be caused by changes in the elastic and viscoelastic properties of the bladder, changes in detrusor muscle tone, or combinations of the two. Management aims at increasing bladder capacity with low intravesical pressure. The main is a medical therapy with antimuscarinics combined with clean intermittent catheterization. The results are sometimes unsatisfactory. Various drugs or agents through the mouth or the bladder, including oxybutynin, new antimuscarinics, capsaicin and resiniferatoxin were tried. Among them botulinum toxin-A is promising. Some patients eventually required surgical intervention in spite of the aggressive medical therapy. Finally most patients undergo the surgical treatment including autoaugmentation, diversion, and augmentation cystoplasty. Among them augmentation cystoplasty still seems the only clearly verified treatment method. [source] DETERMINING NORMAL VALUES FOR INTRA-ABDOMINAL PRESSUREANZ JOURNAL OF SURGERY, Issue 12 2006Joanne J. L. Chionh Background: Intra-abdominal pressure (IAP) measurements can be used for the early detection and management of the abdominal compartment syndrome. IAP values are widely thought to be atmospheric or subatmospheric. However, there are no reports that describe normal IAP values using urinary bladder pressure measurements in patients not suspected of having a raised IAP level. This study sought to determine these normal values to aid our interpretation of IAP measurements in post-surgical patients or patients with suspected increased IAP. Methods: Urinary bladder pressure measurements were carried out in 40 men and 18 women awake medical or non-abdominal surgery inpatients with existing indwelling catheters. Measurements were made in the supine, 30° and 45° sitting positions. Comparisons were carried out to determine the effects on urinary bladder pressure of body position, sex and a suspected diagnosis of benign prostatic hypertrophy. Results: Median values for IAP were higher if measured in a more upright position (P < 0.0001). Median values were supine, 9.5 cmH2O (range, 1,18 cmH2O); 30° upright, 11.5 cmH2O (range, 3,19 cmH2O); and at 45° upright, 14.0 cmH2O (range, 4,22 cmH2O). Measurements recorded were neither atmospheric nor subatmospheric. IAP was higher in men compared with women in the supine and 30° positions (P < 0.05) but not in the 45° position (P = 0.083). There was no significant difference between patients with and without suspected benign prostatic hypertrophy. Conclusions: Normal IAP using urinary bladder pressure in awake patients are above atmospheric pressure. As a patient is moved from the supine into the upright position, IAP measurements increase. [source] Increased postvoid residual volume after measuring the isovolumetric bladder pressure using the noninvasive condom catheter methodBJU INTERNATIONAL, Issue 6 2007Sandra De Zeeuw The papers in this section cover a variety of topics, from urodynamics using a noninvasive method, the morbidity associated with long-term urinary catheters and attempts being made to lower this, the use of botulinum toxin in refractory idiopathic detrusor overactivity, and finally, a study into the effect of chronic prostatitis-like symptoms on the quality of life in a relatively large patient sample. OBJECTIVE To test, in an ongoing noninvasive longitudinal study in healthy men, whether the condom catheter method (a noninvasive urodynamic test to assess bladder function and bladder outlet obstruction) inhibits bladder function and whether this affects the reliability of the measured isovolumetric bladder pressure (Pves.iso). SUBJECTS AND METHODS Subjects (754, aged 40,79 years) voided three times, i.e. one free void and two condom measurements. The postvoid residual volume (PVR) was measured after each void using transabdominal ultrasonography. The statistical significance of differences was tested using Wilcoxon rank test and the Mann,Whitney U -test. RESULTS After free voiding the median (interquartile range) PVR was 18 (37) mL, and independent of the amount of fluid intake. In a subgroup of volunteers, when the free void was done last, the PVR was no different (P = 0.25), suggesting that the bladder did not become exhausted during the protocol. The PVR after two subsequent condom measurements was significantly higher than after free voiding, at 45 (78) and 57 (88) (both P < 0.05), independent of the number of interruptions in voiding. After supplementary fluid intake before the condom measurements, the PVR was double that with a normal fluid intake (P = 0.03). The median Pves.iso was 3 cmH2O higher in the second condom measurement than in the first (P < 0.05), although this small difference was not clinically relevant. CONCLUSIONS The condom measurement is associated with a significantly higher PVR, partly caused by supplementary fluid intake. This effect was only temporary and did not affect the measured Pves.iso. [source] A porcine model of bladder outlet obstruction incorporating radio-telemetered cystometryBJU INTERNATIONAL, Issue 1 2007Matthew B. Shaw OBJECTIVE To present a novel porcine model of bladder outlet obstruction (BOO) with a standardized bladder outlet resistance and real-time ambulatory radio-telemetered cystometry, as BOO is a common condition with many causes in both adults and children, with significant morbidity and occasional mortality, but attempts to model this condition in many animal models have the fundamental problem of standardising the degree of outlet resistance. MATERIALS AND METHODS BOO was created in nine castrated male pigs by dividing the mid-urethra; outflow was allowed through an implanted bladder drainage catheter containing a resistance valve, allowing urine to flow across the valve only when a set pressure differential was generated across the valve. An implantable radio-telemetered pressure sensor monitored the pressure within the bladder and abdominal cavity, and relayed this information to a remote computer. Four control pigs had an occluded bladder drainage catheter and pressure sensor placed, but were allowed to void normally through the native urethra. Intra-vesical pressure was monitored by telemetry, while the resistance valve was increased weekly, beginning with 2 cmH2O and ultimately reaching 10 cmH2O. The pigs were assessed using conventional cystometry under anaesthesia before death, and samples conserved in formalin for haematoxylin and eosin staining. RESULTS The pigs had radio-telemetered cystometry for a median of 26 days. All telemetry implants functioned well for the duration of the experiment, but one pig developed a urethral fistula and was excluded from the study. With BOO the bladder mass index (bladder mass/body mass × 10 000) increased from 9.7 to 20 (P = 0.004), with a significant degree of hypertrophy of the detrusor smooth muscle bundles. Obstructed bladders were significantly less compliant than control bladders (8.3 vs 22.1 mL/cmH2O, P = 0.03). Telemetric cystometry showed that there was no statistically significance difference in mean bladder pressure between obstructed and control pigs (4.8 vs 6.7 cmH2O, P = 0.7), but that each void was longer in the pigs with BOO. CONCLUSION This new model of BOO provides a method of reliably and precisely defining the bladder outlet resistance; it induces the changes classically seen with BOO, including increased bladder mass, increased smooth muscle bundle size and decreased compliance. [source] 78 Use of a rabbit model to investigate the feasibility of using an innervated neosphincter transplant for the treatment of stress urinary incontinence.BJU INTERNATIONAL, Issue 2006A.D. SHAFTON Aim:, To examine the feasibility of using an innervated smooth muscle wrap as a neosphincter in a rabbit model of urinary incontinence. Methods:, Rabbits were rendered incontinent surgically by lesion of the proximal urethral wall to the level of the submucosa (n = 20). In twelve animals a strip of dartos smooth muscle was wrapped around the lesioned urethra to create a new urethral sphincter and stimulating electrodes were inserted into the muscle. After a recovery period of at least one-week cystometrograms were established for control (urethra intact), lesioned and lesion plus neosphincter animals. Results:, Infusion of saline into the bladder of control animals caused a slow rise in bladder pressure until, at approximately 20,30 ml, there was an increase in pressure that rose steeply and was associated with bladder emptying. The threshold for this reflex emptying was 2,3 cm H2O, and the maximum pressure during the reflex was 6,15 cm H2O. After the bladder emptied, the pressure dropped to 0,2 cm H2O. In rabbits with lesioned sphincters, it was not possible to obtain a normal cystometrogram because there was leakage of fluid from the urethral opening before a volume and pressure sufficient to elicit a reflex was achieved. The loss of the majority of fluid often occurred without a significant pressure increase, that is, there was no true emptying reflex. Similar results were observed in animals in which the urethra had been lesioned and implanted with the smooth muscle neosphincter. Prior to electrical stimulation of the neosphincter, with constant current pulses at 2 Hz, substantial leak occurred at 11.4 ± 2.5 ml, whereas during stimulation voiding occurred at 17.8 ± 1.4 ml. At void or emptying, the peak pressure was 6.1 ± 0.1 cm H20 in control, 0.7 ± 0.2 in operated but not stimulated and 3.5 ± 0.6 in the same animals during stimulation. A satisfactory improvement of continence was observed for a period of up to 6˝ months postsurgery. At the end of the study, histological examination confirmed the neosphincter to be both healthy and viable. Conclusion:, Smooth muscles of the dartos display contractile properties which make them suitable for use as transplantable sphincters. A smooth muscle neosphincter, controlled by electrical stimulation, can restore continence after urethral damage. [source] Effects of vaginal distension on urethral anatomy and functionBJU INTERNATIONAL, Issue 4 2002T.W. Cannon Objective ,To determine the effect of repeated and prolonged vaginal distension on the leak-point pressure (LPP) and urethral anatomy in the female rat, as prolonged vaginal distension has been clinically correlated with signs of stress urinary incontinence (SUI). Materials and methods ,Sixty female rats were placed into one of five groups; four groups underwent one of four vaginal distension protocols using a modified 10 F Foley catheter, i.e. prolonged (1 h), brief (0.5 h), intermittent (cycling inflated/deflated for 0.5 h) or sham distension. All animals had a suprapubic bladder catheter implanted 2 days after and were assessed urodynamically 4 days after vaginal distension. The fifth group of rats acted as controls and did not undergo vaginal distension, but did have a suprapubic bladder catheter placed and urodynamics assessed. To measure LPP the rats were anaesthetized with urethane, placed supine and the bladder filled with saline (5 mL/h) while bladder pressure was measured via the bladder catheter. LPPs were measured three times in each animal by manually increasing the abdominal pressure until leakage at the urethral meatus, when the external abdominal pressure was rapidly released. Peak bladder pressure was taken as the LPP and a mean value calculated for each animal. Immediately after measuring LPP the urethra was removed and processed routinely for histology (5 µm sections, stained with haematoxylin/eosin and trichrome). The means ( sem ) were compared using a Kruskal,Wallis one-way anova on ranks, followed by a Dunn's test, with P < 0.05 indicating a significant difference. Results ,Both LPP and the external increase in abdominal pressure were significantly lower after prolonged distension, at 31.4 (1.7) and 19.8 (1.2) cmH 2 O, than in the sham group, at 41.1 (3.2) and 32.0 (4.7) cmH 2 O, respectively. There were no significant differences in LPP or in the increase in abdominal pressure between the brief, intermittent and sham groups. Qualitative histology showed that prolonged distension resulted in extensive disruption and marked thinning of urethral skeletal muscle fibres. Brief and intermittent distension showed mild and focal disruptions, respectively. Conclusions ,As observed clinically, prolonged vaginal distension results in a lower LPP, greater anatomical injury and increased severity of SUI. These results suggest that ischaemia is important in the development of SUI after prolonged vaginal distension. [source] Selective activation of the sacral anterior roots for induction of bladder voidingNEUROUROLOGY AND URODYNAMICS, Issue 2 2006Narendra Bhadra Abstract Aim We investigated the efficacy of selective activation of the smaller diameter axons in the sacral anterior roots for electrically induced bladder voiding. Materials and Methods Acute experiments were conducted in five adult dogs. The anterior sacral roots S2 and S3 were implanted bilaterally with tripolar electrodes. Pressures were recorded from the bladder and from the proximal urethra and the external urethral sphincter. A detector and flow meter monitored fluid flow. A complete sacral dorsal rhizotomy was carried out. The effects of two types of pulse trains at 20 Hz were compared; quasitrapezoidal pulses (500 µsec with 500 µsec exponential decay) and interrupted rectangular (100 µsec, 2 sec on/2 sec off). Before rhizotomy, rectangular pulse trains (100 µsec) to activate all fibers were also applied. The experimental design was block randomized before and after rhizotomy. Results Quasitrapezoidal pulses showed block of sphincter activation with average minimum current for maximum suppression of 1.37 mA. All pulse types evoked average bladder pressures above the basal sphincter closure pressure. The pressure patterns in the proximal urethra closely followed the bladder pressures. Before dorsal rhizotomy, stimulation evoked a superadded increase in sphincter pressures with slow rise time. After rhizotomy, the sphincter pressure patterns followed the bladder pressures during selective activation and voiding occurred during stimulation with quasitrapezoidal trains and in between bursts with interrupted rectangular stimulation. Conclusions Selective activation of sacral ventral roots combined with dorsal rhizotomy may provide a viable means of low-pressure continuous voiding in neurological impairment. Neurourol. Urdynam. © 2005 Wiley-Liss, Inc. [source] Compliance of the bladder neck supporting structures: Importance of activity pattern of levator ani muscle and content of elastic fibers of endopelvic fasciaNEUROUROLOGY AND URODYNAMICS, Issue 4 2003Matija Barbi Abstract Aims Firm bladder neck support during cough, suggested to be needed for effective abdominal pressure transmission to the urethra, might depend on activity of the levator ani muscle and elasticity of endopelvic fascia. Methods The study group of 32 patients with stress urinary incontinence and hypermobile bladder neck, but without genitourinary prolapse, were compared with the control group of 28 continent women with stable bladder neck. The height of the bladder neck (HBN) and compliance of the bladder neck support (C) were assessed, the latter by the quotient of the bladder neck mobility during cough and the change in abdominal pressure. By using wire electrodes, the integrated full-wave rectified electromyographic (EMGave) signal of the levator ani muscle was recorded simultaneously with urethral and bladder pressures. The pressure transmission ratio (PTR), time interval between the onset of muscle activation and bladder pressure increment (,T), and area under the EMGave curve during cough (EMGcough) were calculated. From bioptic samples of endopelvic fascia connecting the vaginal wall and levator ani muscle, elastic fiber content was assessed by point counting method. Mann-Whitney test was used to compare all the variables. Correlations between the parameters were evaluated by using the Spearman correlation coefficient. Results In the study group, HBN was significantly lower (P,<,0.001), C was significantly greater (P,<,0.001), and PTR was significantly lower (P,<,0.001). In the study group, the muscular activation started later (median, ,Tl, ,0.147 second; ,Tr, ,0.150 second), and in the control group, it preceded (,Tl, 0.025 second; P,<,0.001; ,Tr, 0.050 second; P,<,0.001) the bladder pressure increment. EMGcough on the left side was significantly greater in the study group (P,<,0.046). Elastic fiber content showed no difference between the groups. The analysis of all patients revealed negative correlations between C and PTR (r,=,,0.546; P,<,0.001) and between C and ,Tl (r,=,,0.316; P,<,0.018). Conclusions Firm bladder neck support enables effective pressure transmission. Timely activation of the levator ani seems to be an important feature. Neurourol. Urodynam. 22:269,276, 2003. © 2003 Wiley-Liss, Inc. [source] | ||||||||||