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Maximum Flow Rate (maximum + flow_rate)
Selected AbstractsDevelopment of an electrohydraulic total artificial heart system: Improvement of pump unitELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 9 2010Akihiko Homma Abstract An electrohydraulic total artificial heart (EHTAH) system has been developed. The EHTAH system consists of diaphragm-type blood pumps, and electrohydraulic actuator, an internal control unit, a transcutaneous energy transfer system (TETS), a transcutaneous optical telemetry system (TOTS), and an internal battery. The reciprocating rotation of the impeller generates oil pressure that drives the blood pumps at alternating intervals. The blood pumps and the actuator were successfully integrated into the pump unit without oil conduits. As a result of miniaturizing the blood pumps and the actuator, the displacement volume and weight of the EHTAH system were decreased to 872 ml and 2492 g, respectively. Furthermore, the maximum flow rate and efficiency increased up to 12 L/min and 15.4%. The pump units and the EHTAH systems were successfully implanted in 36 calves weighing from 55 to 87 kg. In the longest case, a calf with the pump unit survived for 87 days and a calf with the EHTAH system survived for 70 days. The EHTAH system was powered by the TETS, and was powered every day by the internal battery for 40 minutes. These results indicate that the EHTAH system has the potential to become a fully implantable cardiac replacement system. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(9): 34,46, 2010; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10220 [source] Urodynamic effects of silodosin, a new ,1A -adrenoceptor selective antagonist, for the treatment of benign prostatic hyperplasia,,NEUROUROLOGY AND URODYNAMICS, Issue 4 2010Tomonori Yamanishi Abstract Aims To investigate urodynamically the effects of silodosin, a new ,1A -adrenoceptor-selective antagonist, in the treatment of benign prostatic hyperplasia (BPH). Methods Thirty six male patients with BPH (69.9,±,7.3 years), who were referred as candidates for surgery, were treated with silodosin (4,mg twice daily). The total International Prostate Symptom Score (IPSS) was 20.7,±,7.4, maximum flow rate (Qmax) was 6.7,±,3.0,ml/sec, and prostate volume was 45.6,±,24.5,ml. Results Total IPSS, storage and voiding symptom subscores and QOL score decreased significantly, and Qmax increased significantly after 1,12 months of therapy (all P,<,0.05). In urodynamic study (n,=,29), maximum cystometric capacity increased significantly (P,=,0.0027), and detrusor overactivity disappeared in 8 of 20 patients (40%) and improved (bladder capacity increased more than 50%) in 7 (35%) after the therapy. In pressure/flow studies (n,=,27), the obstruction grade was improved in 15 patients (56%). Detrusor opening pressure, detrusor pressure at Qmax, bladder outlet obstruction index, and Schäfer's obstruction class decreased significantly after therapy (all P,<,0.01). After 12 months, 16 patients (44%) are still on silodosin for 23.3,±,7.0 (range 12,36) months, and the improvements in IPSS and Qmax were stable. Twenty patients withdrew because of insufficient effectiveness in 13 patients (12 patients underwent surgery), side effects in 3, and unknown reasons in 4. Conclusion Silodosin appears to improve detrusor overactivity and obstruction grade in patients with BPH. With silodosin treatment, LUTS could be managed effectively for more than a year in at least 44% of the patients. Neurourol. Urodynam. 29:558,562, 2010. © 2009 Wiley-Liss, Inc. [source] The effect of psychological motivation on volumes voided during uroflowmetry in healthy aged male volunteersNEUROUROLOGY AND URODYNAMICS, Issue 1 2006Yat-Ching Tong Abstract Aims To study the effect of psychological motivation on the voided volume during uroflowmetry in aged-male volunteers. Methods An open contest of free-flow rate was held for the elderly community. People over 60 years old with no prior history of lower urinary tract symptoms were invited to compete. Participants were given the suggestion to void only when strong desire was experienced because greater the volume, faster the flow. One month later, 20 of the male participants were asked to come back for an office uroflowmetry, given the instruction to hold until strong desire was experienced. The results of the maximum flow rate, mean flow rate, and voided volume were compared between these two tests. Results In the first uroflowmetry, the average voided volume for the 20 participants was 532,±,109 ml; maximum flow rate and average flow rate were 27.1,±,9.4, and 17.2,±,6.4 ml/sec, respectively. The voided volume decreased significantly in the second uroflowmetry (338,±,82 ml, P,<,0.01); the maximum and average flow rates did not changed significantly (24.2,±,9.5 and 14.9,±,6.9 ml/sec, respectively). No participant had a shift of more than one standard deviation between the two tests on the Siroky's flow-rate nomogram. Conclusions With psychological motivation to win the contest, the participants showed greater tolerance to bladder filling. This suggests that the state of mind can affect the perception on bladder sensation. On the other, the performance on emptying function is not significantly improved by motivation. Neurourol. Urdynam. © 2005 Wiley-Liss, Inc. [source] Detrusor instability with equivocal obstruction: A predictor of unfavorable symptomatic outcomes after transurethral prostatectomyNEUROUROLOGY AND URODYNAMICS, Issue 5 2002Rintaro Machino Abstract Aims To elucidate whether preoperative urodynamic findings can predict outcomes of transurethral resection of the prostate (TUR-P). Methods Sixty-two patients with symptomatic benign prostatic hyperplasia were categorized in three different ways based on findings of preoperative pressure-flow study (PFS) and cystometry: urodynamic obstruction (determined by the Abrams-Griffiths nomogram), detrusor instability (DI), and combination of both. Outcomes of TUR-P regarding symptom, function, and quality of life (QOL) were analyzed by changes in the International Prostate Symptom Score (I-PSS), maximum flow rate in uroflowmetry, and QOL index before and after TUR-P, respectively. Overall outcome was defined as success when all of the three categories showed successful improvement. Results Neither urodynamic obstruction alone nor DI alone predicted outcomes of TUR-P. However, symptomatic and overall outcomes were significantly worse in patients who were not obstructed but had DI. Postoperative persistent DI was more frequently noted in patients without clear obstruction (60%) than in those with obstruction (27%). Patients with equivocal obstruction showed less satisfactory symptomatic outcomes of TUR-P when DI was accompanied. Persistent DI might be the principle cause of unfavorable outcomes. Conclusions Preoperative evaluation of DI is of benefit because it enhances predictive value of the PFS. Neurourol. Urodynam. 21:444,449, 2002. © Wiley-Liss, Inc. [source] Comparative study of pressure-flow parametersNEUROUROLOGY AND URODYNAMICS, Issue 3 2002Lars M. Eri Abstract Methods for quantification of bladder outlet obstruction (BOO) are still controversial. Parameters such as detrusor opening pressure (pdet.open), maximum detrusor pressure (pdet.max), minimum voiding pressure (pdet.min.void), and detrusor pressure at maximum flow rate (Pdet.Qmax) separate obstructed from nonobstructed patients to some extent, but two nomograms, the Abrams-Griffiths nomogram and the linearized passive urethral resistance relation (LinPURR), are more accepted for this purpose, along with the urethral resistance algorithm. In this retrospective, methodologic study, we evaluated the properties of these parameters with regard to test-retest reproducibility and ability to detect a moderate (pharmacologic) and a pronounced (surgical) relief of bladder outlet obstruction. We studied the pressure-flow charts of 42 patients who underwent 24 weeks of androgen suppressive therapy, 42 corresponding patients who received placebo, and 30 patients who had prostate surgery. The patients performed repeat void pressure-flow examinations before and after treatment or placebo. The various parameters were compared. Among the bladder pressure parameters, Pdet.Qmax seemed to have some advantages, supporting the belief that it is the most relevant detrusor pressure parameter to include in nomograms to quantify BOO. In assessment of a large decrease in urethral resistance, such as after TURp, resistance parameters that are based on maximum flow rate as well as detrusor pressure are preferable. Neurourol. Urodynam. 21:186,193, 2002. © 2002 Wiley-Liss, Inc. [source] The comparative pressure-flow plot properties of radiological bladder neck and prostatic obstructionBJU INTERNATIONAL, Issue 11 2009Sanjin Idriz OBJECTIVES To test the hypotheses that: (i) significant differences should exist in pressure/flow data between radiologically determined bladder neck and prostatic obstruction; (ii) these differences should inform understanding of the pathophysiology of male outflow obstruction. The biomechanics of the voiding/pressure/flow plot imply that a urodynamic assessment trace should identify outflow obstruction and characterise the urethral viscoelastic properties. Micturating cystourethrograms (MCUG) images might provide a useful diagnostic dichotomy for testing these assumptions. MATERIALS AND METHODS The pressure/flow data from 71 men who also provided video-urodynamic imaging data that a radiologist could classify unequivocally as showing bladder neck obstruction (42) or prostatic obstruction (29) were analysed. The following variables were recorded: the detrusor pressure at initiation of voiding (Pdet.open); the detrusor pressure at the end of voiding (Pdet.close); the detrusor pressure at maximum flow rate (Qmax), (Pdet.Qmax), and Qmax. The urethral resistance relation (URR) was drawn onto the pressure-flow plot and the gradient of the URR, ,Pdet/,Q, was calculated. RESULTS There were significant between group differences in Pdet.open (95% confidence interval of the difference 5.2,28.6, U = 352, P = 0.003); Pdet.close (0.2,15.0, U = 428, P = 0.034); Pdet.Qmax (0.0,18.9, U = 439, P = 0.05); Qmax and ,Pdet/,Q did not distinguish between the MCUG groups (95% confidence interval of the difference 2.3,18, U = 111; P = 0.004). The best-fit model from linear combinations of the data achieved an area under the receiver operator curve of 0.72 for discriminating between the MCUG groups. CONCLUSIONS The urodynamic assessment identified interesting and coherent biomechanical differences, and could distinguish between the obstructions with a moderate degree of accuracy. [source] Is it possible to use urodynamic variables to predict upper urinary tract dilatation in children with neurogenic bladder-sphincter dysfunction?BJU INTERNATIONAL, Issue 6 2006Qing Wei Wang In this section, authors from China attempt to use urodynamic indices to predict upper urinary tract dilation in children with neurogenic bladder-sphincter dysfunction. OBJECTIVE To investigate the possibility of using urodynamic variables to predict upper urinary tract dilatation (UUTD) in children with neurogenic bladder-sphincter dysfunction (NBSD). PATIENTS AND METHODS The study included 200 children with NBSD, of whom 103 had UUTD and 97 did not; they were examined using routine urological, neurological and urodynamic methods. The group with UUTD was divided into three subgroups (group 1,3, from mild to severe hydronephrosis). A urodynamic risk score (URS) was calculated, including a detrusor leak-point pressure (DLPP) of >40 cmH2O, a bladder compliance (BC) of <9 mL/cmH2O and evidence of acontractile detrusor (ACD). RESULTS The postvoid residual urine volume (PVR), DLPP, incidences of ACD and DLPP of >40 cmH2O were greater and the BC significantly less in groups 1,3 than in the control group. Moreover, the BC decreased, while the PVR, DLPP and the incidence of DLPP of >40 cmH2O were significantly higher in group 3 than in group 2. The relative safe cystometric capacity of groups 2 and 3 were lower, respectively, than that of the control and group 1, and the relative unsafe cystometric capacity (RUCC) and relative risk rate of cystometric capacity (RRRCC) were significantly greater with the severity of UUTD. The maximum detrusor pressure on voiding or at maximum flow rate, and the Abrams-Griffiths number for voluntary contractile bladders, of the UUTD group were significantly higher than those of the control group. There was a positive correlation between URS and UUTD. CONCLUSIONS The selective use of urodynamic variables might be valuable for predicting the risk of UUTD in children with NBSD. Decreased BC, and increased DLPP and ACD are the main urodynamic risk factors, and they reciprocally increase the occurrence and grades of UUTD. The grades of UUTD are compatible with increases in RUCC, RRRCC and URS. [source] Sustained beneficial effects of intraprostatic botulinum toxin type A on lower urinary tract symptoms and quality of life in men with benign prostatic hyperplasiaBJU INTERNATIONAL, Issue 5 2006Yao-Chi Chuang OBJECTIVE To present a comprehensive experience with intraprostatic botulinum toxin-type A (BoNT-A) injection in men with symptomatic benign prostatic hyperplasia (BPH) and to assess the efficacy on lower urinary tract symptoms (LUTS) and quality of life (QoL). PATIENTS AND METHODS In all, 41 men (mean age 69.1 years, sd 7.1 ) with an International Prostate Symptom Score of ,,8, peak flow rate of <12 mL/s, and who were refractory to medical treatment were injected with BoNT-A (Botox®, Allergan, Inc., CA, USA) at 100 U (21 men, for prostate volume <30 mL) or 200 U (20, for prostate volume >30 mL) into the prostate transperineally under transrectal ultrasonography guidance. Study exclusion criteria were confirmed or suspected malignancy, previous pelvic surgery or trauma and previous invasive treatment for BPH. The clinical effects were evaluated at baseline and at 1, 3 and 6 months after treatment. RESULTS There were no significant local or systemic side-effects in any men. LUTS and QoL indices improved by >30% in 31 of the 41 men (76%), and four of five men with urinary retention for >1 month could void spontaneously at 1 week to 1 month after the BoNT-A injection. In 12 of 41 men (29%) there was no change in prostate volume, yet seven of these men still had a >30% improvement in maximum flow rate, LUTS and QoL. The efficacy was sustained at 12 months. CONCLUSION BoNT-A injected into the prostate is safe and effective for men with symptomatic BPH. The mechanisms of relief of symptoms might not depend totally on the volume shrinkage; the inhibitory effect on the smooth muscle tone and aberrant sensory function might also be important. [source] Antimuscarinic drugs in detrusor overactivity and the overactive bladder syndrome: motor or sensory actions?BJU INTERNATIONAL, Issue 3 2006STEVEN M. FINNEY Antimuscarinic drugs are generally thought to exert their therapeutic action on detrusor overactivity by reducing the ability of the detrusor muscle to contract. We review currently available published data to establish whether there is any evidence to support this contention. Using a PubMed data search, only 14 original articles (including two abstracts) were found that contained cystometric data for both filling and voiding phases and where the actions of antimuscarinic drugs have been reported in detail. These articles were separated into three groups dealing with neuropathic patients (three papers), patients with idiopathic overactive bladder (four papers) and a group whose aetiology was unclear (seven papers). Variables relating to bladder function during the filling phase (time of first desire to void, time to first unstable contraction, and bladder capacity) were identified. Similarly, variables relating to voiding were identified and compared (e.g. maximum detrusor pressure and detrusor pressure at maximum flow rate). The antimuscarinic drugs have a clearly significant effect on sensations of urge, time to first sensation to void, maximum bladder capacity, decrease in voiding frequency and reduction in incontinence episodes. However, only one article (studying neuropaths) reported a significant reduction of the variables associated with detrusor contraction. The remaining four studies (idiopaths/not stated), reported no change in bladder contractility with antimuscarinic drugs. Thus the available data do not support the conclusion that antimuscarinic drugs at doses used in current clinical practice exert their therapeutic action by inhibiting detrusor contractility, but they suggest effects on variables associated with sensation. [source] Comparison of tamsulosin and naftopidil for efficacy and safety in the treatment of benign prostatic hyperplasia: a randomized controlled trialBJU INTERNATIONAL, Issue 4 2005Momokazu Gotoh OBJECTIVES To compare the efficacy and safety of two ,1a/,1d adrenoceptor (AR) antagonists with different affinity for the ,1AR subtypes, tamsulosin and naftopidil, in the treatment of benign prostatic hyperplasia (BPH). PATIENTS AND METHODS Patients with BPH were randomized to receive either tamsulosin or naftopidil. The primary efficacy variables were the changes in the total International Prostate Symptom Score (IPSS), maximum flow rate on free uroflowmetry, and residual urine volume. The secondary efficacy variables were average flow rate, changes in the IPSS storage score, IPSS voiding score, and quality-of-life (QoL) Index score, from baseline to endpoint (12 weeks). Data on all randomized patients were included in the safety analyses for adverse effects and changes in blood pressure. RESULTS Of the 185 patients enrolled data for 144 who were eligible for inclusion in the efficacy analysis were analysed (75 from the tamsulosin and 69 from the naftopidil group). There was no significant difference in any variable at baseline between the groups. There were satistically significant improvements for all primary and secondary variables in both groups, except for residual urine in the tamsulosin group. However, there was no significant intergroup difference in the improvement of any efficacy variable between the groups. The adverse effects were comparable, with no significant differences in systolic and diastolic blood pressure after treatment in both groups. CONCLUSIONS This study suggests that naftopidil is as effective and safe as tamsulosin. Both drugs were effective in improving storage and voiding symptoms. However, there was no difference in clinical efficacy or adverse effects between the ,1 AR antagonists with different affinity to ,1 subtypes, ,1a and ,1d. [source] Is the conservative management of chronic retention in men ever justified?BJU INTERNATIONAL, Issue 6 2003T.S. Bates OBJECTIVE To assess the outcome of men presenting with lower urinary tract symptoms (LUTS) associated with large postvoid residual urine volumes (PVR). PATIENTS AND METHODS The study included men presenting with LUTS and a PVR of >,250 mL who, because of significant comorbidity, a low symptom score or patient request, were managed conservatively and prospectively, and were followed with symptom assessment, serum creatinine levels, flow rates and renal ultrasonography. Patients were actively managed if there was a history of previous outflow tract surgery, prostate cancer, urethral strictures, neuropathy, elevated creatinine or hydronephrosis. In all, 93 men (mean age 70 years, range 40,84) with a median (range) PVR of 363 mL (250,700) were included in the study and followed for 5 (3,10) years. At presentation, the median maximum flow rate was 10.2 (3,30) mL/s and the voided volume 316 (89,714) mL. RESULTS The measured PVR remained stable in 47 (51%), reduced in 27 (29%) and increased in 19 (20%) patients; 31 patients (33%) went on to transurethral resection of the prostate after a median of 30 (10,120) months, because of serum creatinine elevation (two), acute retention (seven), increasing PVR (eight) and worsening symptoms (14). Of 31 patients 25 were available for evaluation after surgery; their median PVR was 159 (0,1000) mL, flow rate 18.4 (4,37) mL/s and voided volume 321 (90,653) mL. Symptoms were improved in all but five men. There was no difference in initial flow rate, voided volume or PVR between those who developed complications or went on to surgery and those who did not. Urinary tract infections (UTIs) occurred in five patients and two developed bladder stones. CONCLUSIONS Complications such as renal failure, acute retention and UTIs are uncommon in men with large, chronic PVRs. Conservative management for this group of patients is reasonable but outpatient review is prudent. There were no factors that could be used to predict those patients who eventually required surgery. [source] The correlation of voiding variables between non-instrumented uroflowmetery and pressure-flow studies in women with pelvic organ prolapseNEUROUROLOGY AND URODYNAMICS, Issue 6 2008Elizabeth Mueller Abstract Aims To (1) correlate peak and maximum flow rates from non-instrumented flow (NIF) and pressure-flow studies (PFS) in women with pelvic organ prolapse (POP); (2) measure the impact of voided volume and degree of prolapse on correlations. Methods We compared four groups of women with stages II,IV POP. Groups 1 and 2 were symptomatically stress continent women participating in the colpopexy and urinary reduction efforts (CARE) trial; during prolapse reduction before sacrocolpopexy, Group 1 (n,=,67) did not have and Group 2 (n,=,84) had urodynamic stress incontinence (USI). Group 3 (n,=,74) and Group 4 participants (n,=,73), recruited specifically for this study, had stress urinary incontinence (SUI) symptoms. Group 3 planned sacrocolpopexy. Group 4 planned a different treatment option. Participants completed standardized uroflowmetry and pressure voiding studies. Results Subjects' median age was 61 years; median parity 3% and 80% had stage III or IV POP. Based on the Blaivas,Groutz nomogram, 49% of all women were obstructed. NIF and PFS peak and average flow rates had low correlations with one another (0.31, P,<,0.001 and 0.35, P,<,0.001, respectively). When NIF and PFS voided volumes were within 25% of each other, the peak and average flow rate correlations improved (0.52, P,<,0.001 and 0.57, P,<,0.001, respectively). As vaginal prolapse increased, correlations between NIF and PFS peak and average flow rates decreased. Conclusion Peak and average flow rates are highly dependent on voided volume in women with prolapse. As the prolapse stage increases, correlations between NIF and PFS variables decrease. Neurourol. Urodynam. 27:515,521, 2008. © 2008 Wiley-Liss, Inc. [source] Mischer mit mikrostrukturierten Folien für chemische ProduktionsaufgabenCHEMIE-INGENIEUR-TECHNIK (CIT), Issue 5 2004B. Werner Abstract Seit etwa 10 Jahren beschäftigt sich die Institut für Mikrotechnik Mainz GmbH (IMM) mit der Nutzung von Mikrostrukturen im Bereich der Mikroverfahrenstechnik. Deren Vorteile , effizienterer Wärmeaustausch und Massentransport , bewirken u.,a. Steigerung von Ausbeute und Selektivität bei gleichzeitiger Ressourcenschonung. Die Entwicklung von mikrostrukturierten Mischern war dabei ein Schlüssel zu verbesserten Feinchemikaliensynthesen sowie zur Herstellung von Dispersionen, Cremes, Schäumen und Emulsionen. Bislang waren diese mikrostrukturierten Mischer im Wesentlichen auf Labor- oder bestenfalls Pilotanlagen-Maßstab festgelegt , typische Maximalflussraten lagen bei 2,, 100,L/h für wasserähnliche Fluidsysteme. Mit der Einführung der StarLaminatoren StarLam300 und StarLam3000, konnte diese Grenze jetzt auf weit über 300,L/h bis in den m3/h-Bereich angehoben werden. Beide Apparate zeigen gute Mischgüten bei hohen Flüssen, die durchaus an die sehr guten Werte von bisher bekannten Niederdurchsatz(L/h)-Mikromischer heranreichen. Damit ist eine Kontinuität von ,wirklichen" Mikromischern über die hier beschriebenen Hochdurchsatz-Tools bis zu statischen Mischern mit noch höheren Durchsätzen gegeben. Eine Klassifikation der Mischeffizienz nach dem Leistungseintrag bestätigt ebenso diese Kontinuität. Mixers with Microstructured Foils for Chemical Production Purposes Since about 10 years the Institut für Mikrotechnik Mainz GmbH (IMM) is engaged with the application of microstructures for chemical micro process engineering. Their advantages , more efficient heat exchange and mass transport , lead to, among other things, an increase in yield and selectivity even while saving resources. The development of microstructured mixers thereby played a key role for carrying out advanced syntheses of fine chemicals as well as for the generation of dispersions, creams, foams, and emulsions. So far, microstructured mixers were mainly limited for laboratory-scale or at best pilot plant-scale , typical maximum flow rates were from 2 , 100 L/h for watery fluid systems. With the introduction of the StarLaminators StarLam300 and StarLam3000 this barrier could be lifted far beyond 300 L/h up to the m3/h domain. Both apparatus yield at high flow rates a mixing efficiency which reaches the high performance of today's low-capacity (L/h) micro mixers. Therefore, continuity from the "real" micro mixers over the herein described high-throughput tools to conventionally manufactured static mixers with even higher flow rates is given. [source] | ||||||||||