title: Variability of pressure-flow analysis parameters in repeated cystometry in patients with benign prostatic hyperplasia.
abstract: Urodynamic investigation becomes increasingly important in the diagnosis of bladder outflow obstruction in patients with benign prostatic hyperplasia. To date, different methods for evaluation of the pressure-flow relationship and quantification of the grade of obstruction are available. Models for pressure-flow analysis are briefly explained. The variability of the parameters is investigated by evaluation of 75 patients in whom 2 sequential voidings during urodynamic investigation were analyzed. The results showed that in 87% of these patients individual maximum flow differences of first and second voidings were less than 2 ml. per second. Individual detrusor pressure at maximum flow differences were less than 15 cm. water in 80% of these patients, while in 80% the intra-individual variation of the pressure-flow results was less than 15 cm. water for the minimal voiding pressure parameters (minimal urethral opening detrusor pressure and urethral resistance factor). For the pressure-flow parameter that defines the theoretical urethral lumen during voiding, the variation was less than 1.5 mm.2 in 84% of the patients. Patients with larger intra-individual differences are discussed. We concluded that the observed, aforementioned differences can be regarded as an indication of normal intra-individual variability of voiding during urodynamic investigation. This intra-individual variability, however, seldom leads to a change in the clinical grade of bladder outflow obstruction. We conclude that investigators involved in therapeutic trials of benign prostatic hyperplasia must be aware of this intra-individual variability of micturition, since this variability is greater than the refined scale of the pressure-flow analysis models.
authors.affiliation: Department of Urology, University Hospital Nijmegen, The Netherlands.
authors.forename: P F
authors.initials: PF
authors.lastname: Rosier
authors.forename: J J
authors.initials: JJ
authors.lastname: de la Rosette
authors.forename: E L
authors.initials: EL
authors.lastname: Koldewijn
authors.forename: F M
authors.initials: FM
authors.lastname: Debruyne
authors.forename: H
authors.initials: H
authors.lastname: Wijkstra
mesh_terms: D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D011312:Pressure; D011470:Prostatic Hyperplasia / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D015203:Reproducibility of Results; D014521:Urethra / Q000503:physiopathology; D001743:Urinary Bladder / Q000503:physiopathology*; D001748:Urinary Bladder Neck Obstruction / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D014563:Urodynamics / Q000502:physiology*