Quantitative quality control during urodynamic studies with TVRs for cystometry in men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia

Abstract

To establish typical value ranges (TVRs) and to outline their role in urodynamic quality control. Five hundred and eighty-two data sets of free flow, filling cystometry, and voiding from 181 males in a strictly quality-controlled study were analyzed for intravesical pressure (Pves), abdominal pressure (Pabd), and detrusor pressure (Pdet) before, at the beginning and end of filling, and after voiding. Cystometric capacity, maximum flow rate (Qmax), voided volume (Vvoid), and compliance were determined. Mean value, standard deviation, median, and various TVRs were calculated. Technical errors related to the TVRs are classified and examples given. TVRs for initial resting Pves, Pabd, and Pdet were 31-42, 28-39, and 0-4 cmH₂O, respectively. Various technical errors are classified as type I: normal initial Pdet, both Pves and Pabd are incorrect; type II: negative initial Pdet; and type III: initial Pdet too high. The incidences of I, II, and III errors were 9.8, 4.5, and 1.4%, respectively. The TVRs for maximum cystometric capacity and compliance were 157-345 mL and 26.7-70.8 mL/cmH₂O; Qmax, Pdet, and Vvoid were 5.5-9 mL/s, 57-92 cmH₂O, and 167-315 mL, respectively; Qmax and Vvoid in free flow were 8-9.2 mL/s and 167-301 mL, respectively. After voiding, two errors were found: type V (Pves and Pdet after voiding still high) and type VI (Pves and Pdet negative). TVRs in urodynamics are indispensable and effective tools for quantitative plausibility checks and quality control. They are sensitive and reliable indicators for correct measurement and a relevant contribution to a collection of normal values.