Aim： To compare the use of the suprapubic puncture method versus the transurethral method in pressure-flow studies in patients with benign prostatic hyperplasia. Methods： Twenty-three men with benign prostatic hyper...Aim： To compare the use of the suprapubic puncture method versus the transurethral method in pressure-flow studies in patients with benign prostatic hyperplasia. Methods： Twenty-three men with benign prostatic hyperplasia underwent both suprapubic and transurethral pressure-flow studies during a single session. Standard pressure-flow variables were recorded in all patients with both methods, enabling calculation of obstruction using commonly used grading systems, such as the urethral resistance algorithm, the Abrams-Griffith （AG） number and the Schaefer linear nomogram. Results： There were statistically significant differences between the methods in the mean values of maximum flow rate （P 〈 0.05）, detrusor pressure at the maximum flow （P 〈 0.01）, urethral resistance algorithm （P 〈 0.01）, AG number （P 〈 0.01） and maximum cystic capacity （P 〈 0.01）. Of the men in the study, 10 （43.5%） remained in the same Schaefer class with both methods and 18 （78.3%） in the same AG number area. Using the transurethral method, 12 （52.2%） men increased their Schaefer class by one and 1 （4.3%） by two. There were also differences between the suprapubic and transurethral methods using the AG number： 4 （17.4%） men moved from a classification of equivocal to obstructed and 1 （4.3%） from unobstructed to equivocal. Conclusion： The differences between the techniques for measuring intravesical pressure alter the grading of obstruction determined by several of the commonly used classifications. An 8 F transurethral catheter significantly increases the likelihood of a diagnosis of bladder outlet obstruction when compared with the suprapubic method.展开更多
Aim： To evaluate the effects of retrospective quality control on pressure-flow data with computer-based urodynamic systems from men with benign prostatic hyperplasia （BPH）. Methods： A total of 582 traces of pressu...Aim： To evaluate the effects of retrospective quality control on pressure-flow data with computer-based urodynamic systems from men with benign prostatic hyperplasia （BPH）. Methods： A total of 582 traces of pressure-flow study from 181 men with BPH was included in the study. For each trace, maximum urinary flow rate （Qmax） and detrusor pressure at Qmax （pdet.Qmax） were, respectively, read from manually smoothed and corrected uroflow and detrusor pressure curves from the computer print-outs. Obstruction coefficient, International Continence Society （ICS） and Schaefer nomograms were used to detect urethral resistance and to diagnose obstruction. The results obtained by manual reading were compared with those from computer-based systems. Results： After manual correction, Qmax underwent a consistently significant decrease by 1.2 mL/s on average （P 〈 0.001）, and had a change range of 0.5-10.4 mL/s. However, pdet.Qmax underwent inconsistently intra-individual changes after correction. The obstruction coefficient increased significantly, by an average of 0.07 （P 〈 0.05）. Using the ICS nomogram, the percentage of obstruction increased from 69.8% to 73.9%, and of the non-obstruction decreased from 8.8% to 5.3% （P 〈 0.05）. There were 11% of traces that changed the classifications using the ICS nomogram, and 28.9% that changed the grades for the Schaefer nomogram. Conclusion： Systematically significant differences in parameters from pres- sure-flow study between manual readings and computer recordings were demonstrated. Manual correction resulted in a consistently lower Q a higher urethral resistance, and an aggravating obstruction. Manual readings can correct considerable false diagnoses for obstruction. Retrospective quality control of pressure-flow data with com- puter-based systems is necessary.展开更多
The structure principles under the flow and pressure working conditions are studied,in order to investigate the dynamic characteristics of the electro-hydraulic proportional pressure-flow hybrid valve.According to the...The structure principles under the flow and pressure working conditions are studied,in order to investigate the dynamic characteristics of the electro-hydraulic proportional pressure-flow hybrid valve.According to the structure principles under the two different working conditions,the transfer functions under such conditions are derived.With the transfer functions,some structure elements that may affect its performance,are investigated,afterwards some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed.The conclusions can be used to instruct engineering applications and products designing.The test results conform to the results of the theoretical analysis and simulation,which proves the correctness of the study and simulation works.展开更多
Changes in intramyocardial tissue pressure modulate the relationship between coronary pressure and flow during the cardiac cycle. The present study compared the relation between measured and calculated diastolic suben...Changes in intramyocardial tissue pressure modulate the relationship between coronary pressure and flow during the cardiac cycle. The present study compared the relation between measured and calculated diastolic subendocardial tissue pressure and coronary pressure at zero flow in anesthetized dogs after modulation of either coronary sinus (i.e. Fogarty catheter) or left ventricular intracavity (i.e. volume loading) pressure. Experiments were conducted in anesthetized, instrumented dogs;coronary pressure flow relations were constructed during pharmacologic vasodilatation and intramyocardial tissue pressure was measured using micromanometer pressure sensors. Elevated coronary sinus pressures did not affect subendocardial pressure-flow relations signifying that diastolic tissue pressure within this layer is the effective coronary back pressure. Higher left ventricular intracavity pressure did not affect either diastolic subendocardial tissue pressure or pressure flow relations within this layer. Results show a direct linear relation (y = 1.106x - 0.652;r2 = 0.59. P = 0.001) between measured and calculated diastolic subendocardial tissue pressure and coronary pressure at zero-flow over a wide range of pressures after either LV systemic or coronary sinus pressure modulation. Knowledge of back pressure in the subendocardium is useful for the evaluation of efficacy of cardiac interventions on myocardial perfusion particularly at the level of the microcirculation.展开更多
Pressure-flow study(PFS) of micturition is the best method to quantitatively analyse voiding function. It allows us to distinguish voiding lower urinary tract symptoms and low urine flow rate caused by bladder outlet ...Pressure-flow study(PFS) of micturition is the best method to quantitatively analyse voiding function. It allows us to distinguish voiding lower urinary tract symptoms and low urine flow rate caused by bladder outlet obstruction(BOO) from those caused by detrusor underactivity(DU). Voiding dynamics are significantly different in men and women and the established criteria for urodynamic diagnosis in men do not apply to women. Basic principles of voiding mechanics and voiding patterns in asymptomatic women are analyzed. Although attempts have been made to establish a consensus for diagnosis of BOO in women with pressure-flow cutoff, video-urodynamics criteria and nomograms, currently there is no consensus. There is no standard urodynamic test to diagnose and quantify DU in women for which further investigations are needed. Modified projected isovolumetric pressure(to assess detrusor contraction strength) and pressure-flow cutoff criteria have been used. The diagnosis of voiding dysfunction in women is challenging, requiring PFS with very good quality control and often involves integrating clinical and radiographic data to make the final assessment.展开更多
文摘Aim： To compare the use of the suprapubic puncture method versus the transurethral method in pressure-flow studies in patients with benign prostatic hyperplasia. Methods： Twenty-three men with benign prostatic hyperplasia underwent both suprapubic and transurethral pressure-flow studies during a single session. Standard pressure-flow variables were recorded in all patients with both methods, enabling calculation of obstruction using commonly used grading systems, such as the urethral resistance algorithm, the Abrams-Griffith （AG） number and the Schaefer linear nomogram. Results： There were statistically significant differences between the methods in the mean values of maximum flow rate （P 〈 0.05）, detrusor pressure at the maximum flow （P 〈 0.01）, urethral resistance algorithm （P 〈 0.01）, AG number （P 〈 0.01） and maximum cystic capacity （P 〈 0.01）. Of the men in the study, 10 （43.5%） remained in the same Schaefer class with both methods and 18 （78.3%） in the same AG number area. Using the transurethral method, 12 （52.2%） men increased their Schaefer class by one and 1 （4.3%） by two. There were also differences between the suprapubic and transurethral methods using the AG number： 4 （17.4%） men moved from a classification of equivocal to obstructed and 1 （4.3%） from unobstructed to equivocal. Conclusion： The differences between the techniques for measuring intravesical pressure alter the grading of obstruction determined by several of the commonly used classifications. An 8 F transurethral catheter significantly increases the likelihood of a diagnosis of bladder outlet obstruction when compared with the suprapubic method.
文摘Aim： To evaluate the effects of retrospective quality control on pressure-flow data with computer-based urodynamic systems from men with benign prostatic hyperplasia （BPH）. Methods： A total of 582 traces of pressure-flow study from 181 men with BPH was included in the study. For each trace, maximum urinary flow rate （Qmax） and detrusor pressure at Qmax （pdet.Qmax） were, respectively, read from manually smoothed and corrected uroflow and detrusor pressure curves from the computer print-outs. Obstruction coefficient, International Continence Society （ICS） and Schaefer nomograms were used to detect urethral resistance and to diagnose obstruction. The results obtained by manual reading were compared with those from computer-based systems. Results： After manual correction, Qmax underwent a consistently significant decrease by 1.2 mL/s on average （P 〈 0.001）, and had a change range of 0.5-10.4 mL/s. However, pdet.Qmax underwent inconsistently intra-individual changes after correction. The obstruction coefficient increased significantly, by an average of 0.07 （P 〈 0.05）. Using the ICS nomogram, the percentage of obstruction increased from 69.8% to 73.9%, and of the non-obstruction decreased from 8.8% to 5.3% （P 〈 0.05）. There were 11% of traces that changed the classifications using the ICS nomogram, and 28.9% that changed the grades for the Schaefer nomogram. Conclusion： Systematically significant differences in parameters from pres- sure-flow study between manual readings and computer recordings were demonstrated. Manual correction resulted in a consistently lower Q a higher urethral resistance, and an aggravating obstruction. Manual readings can correct considerable false diagnoses for obstruction. Retrospective quality control of pressure-flow data with com- puter-based systems is necessary.
文摘The structure principles under the flow and pressure working conditions are studied,in order to investigate the dynamic characteristics of the electro-hydraulic proportional pressure-flow hybrid valve.According to the structure principles under the two different working conditions,the transfer functions under such conditions are derived.With the transfer functions,some structure elements that may affect its performance,are investigated,afterwards some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed.The conclusions can be used to instruct engineering applications and products designing.The test results conform to the results of the theoretical analysis and simulation,which proves the correctness of the study and simulation works.
文摘Changes in intramyocardial tissue pressure modulate the relationship between coronary pressure and flow during the cardiac cycle. The present study compared the relation between measured and calculated diastolic subendocardial tissue pressure and coronary pressure at zero flow in anesthetized dogs after modulation of either coronary sinus (i.e. Fogarty catheter) or left ventricular intracavity (i.e. volume loading) pressure. Experiments were conducted in anesthetized, instrumented dogs;coronary pressure flow relations were constructed during pharmacologic vasodilatation and intramyocardial tissue pressure was measured using micromanometer pressure sensors. Elevated coronary sinus pressures did not affect subendocardial pressure-flow relations signifying that diastolic tissue pressure within this layer is the effective coronary back pressure. Higher left ventricular intracavity pressure did not affect either diastolic subendocardial tissue pressure or pressure flow relations within this layer. Results show a direct linear relation (y = 1.106x - 0.652;r2 = 0.59. P = 0.001) between measured and calculated diastolic subendocardial tissue pressure and coronary pressure at zero-flow over a wide range of pressures after either LV systemic or coronary sinus pressure modulation. Knowledge of back pressure in the subendocardium is useful for the evaluation of efficacy of cardiac interventions on myocardial perfusion particularly at the level of the microcirculation.
文摘Pressure-flow study(PFS) of micturition is the best method to quantitatively analyse voiding function. It allows us to distinguish voiding lower urinary tract symptoms and low urine flow rate caused by bladder outlet obstruction(BOO) from those caused by detrusor underactivity(DU). Voiding dynamics are significantly different in men and women and the established criteria for urodynamic diagnosis in men do not apply to women. Basic principles of voiding mechanics and voiding patterns in asymptomatic women are analyzed. Although attempts have been made to establish a consensus for diagnosis of BOO in women with pressure-flow cutoff, video-urodynamics criteria and nomograms, currently there is no consensus. There is no standard urodynamic test to diagnose and quantify DU in women for which further investigations are needed. Modified projected isovolumetric pressure(to assess detrusor contraction strength) and pressure-flow cutoff criteria have been used. The diagnosis of voiding dysfunction in women is challenging, requiring PFS with very good quality control and often involves integrating clinical and radiographic data to make the final assessment.
