Sam TILBORGHS 1, Stefan DE WACHTER 1, Anna BAEL 2, Karen DE BAETS 1 and Gunter DE WIN 1
1) Antwerp University Hospital, Department of Urology, Edegem, BELGIUM – 2) Antwerp Hospital Network (ZNA), Queen Paola Children’s Hospital, Antwerp, BELGIUM
Single measurement uroflows, obtained in an unnatural environment (hospital) often result in unreliable data, especially in children. The aim of this study is to assess the variability of uroflowmetries in children using Homeflow – a portable home-uroflowmeter, fitting on a normal toilet.
MATERIAL AND METHODS
Multiple uroflows (177) were assessed in 11 children (boys/girls: 9/2; mean age: 10,36 +/- 5,15). The variability of the maximum flow rate (Qmax) and flow curve were analysed in relation to urge, time of the day and voided volume (Vvoid).
We found individual ranges of the intra-subject Standard Deviation (SD) of multiple measurements of Qmax between 0,86 and 9,94 ml/sec. With a moderate intra-subject SD of 4 ml/sec, Qmax may vary by up to 12 ml/sec (3SD) due to random fluctuation alone. Variability in Qmax and flow curve shape could be dependent on time of day, urge and/or Vvoid. Qmax-Vvoid correlation of multiple uroflows in one individual are interesting to investigate and compare with conventional nomograms.
There was a significant intra-variability in Qmax and flow curve with each successive void. Multiple measurements influence extreme values (either outliers or unrepresentative flows), counteracting the large potential error in a single measurement. Due to this variability, comparison between single in-clinic flows in an individual is less powerful – definitely, considering the psychological effects of the hospital environment on a child. Our results underline the clinical potential of Homeflow. The cohesion of depending factors determing Qmax, Vvoid, flowcurve and urge is complex and needs more research.
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