Comparison of flowrates and voided volumes during non-instrumented uroflowmetry and pressure-flow studies in women with stress incontinence

Elizabeth R. Mueller, Heather Litman, Leslie R. Rickey, Larry Sirls, Peggy Norton, Tracey Wilson, Pamela Moalli, Michael Albo, Philippe Zimmern

Research output: Contribution to journalArticle

2 Scopus citations


Aims The Blaivas-Groutz nomogram defines voiding obstruction in women using Q<inf>max</inf> from the NIF and the maximum detrusor pressure (P<inf>detmax</inf>) from the PFS. The aim of this study was to understand the relationship between NIF and PFS maximum flow rates in women with stress incontinence. Methods We analyzed the UDS of 597 women with stress-dominant urinary incontinence. Each subject underwent a NIF and then a PFS. Mixed model was used to test the hypothesis that the relationship between flow rates and voided volume (VV) were similar for NIF and PFS. Results There were 452 subjects with both NIF and PFS studies that met the inclusion criteria and had max flow rate (Q<inf>max</inf>) for both NIF and PFS. The mean age was 53. Overall, higher VV were observed during PFS compared to NIF and subjects had higher Q<inf>max</inf> with NIF compared to PFS. The relationship between Q<inf>max</inf> and VV was significantly different between NIF and PFS (P<0.004). At 200ml, NIF Q<inf>max</inf> was 14% higher than PFS Q<inf>max</inf> and this difference increased to 30% at 700ml. Conclusion The difference between PFS Q<inf>max</inf> and NIF Q<inf>max</inf> increases as VV increase. As a result, values from PFS and NIF cannot be used interchangeably as has been suggested in the Blaivas-Groutz nomogram for obstruction in women.

Original languageEnglish (US)
Pages (from-to)549-553
Number of pages5
JournalNeurourology and Urodynamics
Issue number6
StatePublished - Aug 1 2015



  • obstruction
  • pelvic organ prolapse
  • stress incontinence
  • urodynamics
  • uroflowmetry
  • women

ASJC Scopus subject areas

  • Clinical Neurology
  • Urology

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