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Flow measurements: Can several “Wrongs” make a “Right”?
Author(s) -
Caffarel Jennifer,
Robson Wendy,
Pickard Robert,
Griffiths Clive,
Drinnan Michael
Publication year - 2007
Publication title -
neurourology and urodynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 90
eISSN - 1520-6777
pISSN - 0733-2467
DOI - 10.1002/nau.20383
Subject(s) - medicine , limits of agreement , flow (mathematics) , mean difference , maximum flow problem , volumetric flow rate , nuclear medicine , mathematics , mechanics , physics , combinatorics , confidence interval
Aims Although measurement of maximum flow rate (Q max ) is a standard and straightforward test, it is often difficult to obtain reliable readings. We obtained multiple measurements using a simple home uroflow device which categorizes Q max into ranges. We hypothesize that the average of a series of relatively coarse measurements of Q max would be more repeatable and therefore more representative of an individual's voiding function than a single, albeit more precise measurement. Methods We studied 22 male volunteers with a wide range of Q max . They were asked to record flow category (<10 ml/sec; 10–15 ml/sec; 15–20 ml/sec; >20 ml/sec) and voided volume twice daily for 12 days using the home flow device. In addition, a clinic‐based flow recording using a spinning‐disc uroflowmeter was obtained at both the start and the end of the 12‐day period. Results Good agreement between mean home flow and mean clinic flow was seen with mean (SD) difference of 1.3 (5) ml/sec. The mean for consecutive halves of an individual's home flow data showed excellent agreement (−0.2 (1.3) ml/sec). The two clinic readings showed poorer agreement (2.3 (6.8) ml/sec) than the home readings, and poorer agreement even than between clinic and home flows. Conclusions Although simple in design, the home flowmeter actually shows greater accuracy than might be expected when used repeatedly to study the flow rates of men. Simple flow devices such as this could be used in conjunction with voiding diaries to give a more representative picture of patients' day‐to‐day voiding function. Neurourol. Urodynam. 26:474–480, 2007. © 2007 Wiley‐Liss, Inc.