Development of Urodynamic Standards for Quality Control

International Continence Society Good Urodynamic Practices and Terms 2016: Urodynamics, uroflowmetry, cystometry, and pressure‐flow study

“…1,2,5,79 Typical signal patterns, such as straining, rectal contractions, coughing and DO are important in quality control and everyone who performs or evaluates urodynamic tests should be able to recognize these during the test. 66,87,[96][97][98][99][100] In diverse retrospective single and multicenter evaluations, it was demonstrated that the expert recognition and identification of specific patterns occurring in the urodynamic traces has required adaption or correction of the-initial-diagnoses. 19…”

Flow resistive forces index (QRF): Development and clinical applicability assessment of a novel measure of bladder outlet resistance, aiming to enhance the diagnostic performance of uroflowmetry

“…In terms of hydrodynamics, voiding ensues due to the action of a resultant force that produces the impulse required to sufficiently change the momentum of a given volume of urine on which it is applied. 6,13,14 In fluid mechanics, the analysis of motion is performed by use of Newton's laws of motion from which Newton's second law states that the rate of [= dv body /dt]). [14][15][16][17] During voiding, urine is considered to behave as a Newtonian fluid (defined as one that is incompressible with friction losses, and its flow is nonstationary, turbulent, and isothermal), rendering thus the above principles applicable to its flow kinetics analysis.…”

“…[1][2][3][4] Key parameters are maximum flow rate (Q max ) and flow pattern, with Q max representing the most relevant variable when assessing bladder outflow and the only variable so far submitted to extensive quantitative investigation. 1,5,6 However, its diagnostic accuracy for detecting BOO varies considerably, is substantially influenced by threshold values, and is generally found to be low (inconclusive sensitivity, poor specificity) since decreased/low Q max values can result from outflow obstruction, impaired detrusor contractility (DC), or a combination of both. Furthermore, there are no features of the uroflow curve shape that allow a definitive distinction between outlet obstruction and detrusor underactivity.…”

“…Furthermore, there are no features of the uroflow curve shape that allow a definitive distinction between outlet obstruction and detrusor underactivity. [1][2][3][4][6][7][8][9][10] Thus, uroflow tests are limited by their inability to discriminate between the underlying mechanisms and cannot be used alone to offer a precise diagnosis as to the cause of abnormal flow, especially in complex cases. Rather they should be seen merely as general indicators of voiding dysfunction suggestive of second-stage investigation in order for a definitive diagnosis to be made.…”

“…Rather they should be seen merely as general indicators of voiding dysfunction suggestive of second-stage investigation in order for a definitive diagnosis to be made. 1,3,4,6,[8][9][10] In a large part, these limitations are attributed to the fact that, although each free uroflow curve contains a large amount of information, in practice the classical methods of analysis usually take into account only a small part of this information (Q max , flow pattern). 7,11,12 Aiming to improve the diagnostic performance of uroflowmetry as a clinical test to detect BOO by extracting the maximum amount of data from the available information (voided volume, flow time, Q max , average flow rate [Q ave ], peak flow time), we developed a mathematical formula to calculate the flow resistive forces index (QRF), a novel measure of bladder outlet/urethral resistance, and assessed its clinical applicability compared to the standard indicator Q max .…”