Effect of abdominal straining on urinary flow rate in normal males.
The measurement of urinary flow rate by uroflowmetry and its relationship to voided volume and age have been extensively studied. It is well recognised that some men void with abdominal straining, but any effect of this on the urinary flow rate is usually not taken into account in urological practice. The aim of this study was to determine whether abdominal straining had any significant influence on the urinary flow rate. Three male volunteers performed multiple voidings either with or without abdominal straining. Statistical transformation of the data and the use of co-variant analysis allowed a comparison between "normal" or passive voiding and voiding with abdominal straining. The results showed that abdominal straining caused a significant improvement in both the average and maximum urinary flow rate. If the effect of abdominal straining is not taken into account during the interpretation of uroflowmetry results, incorrect conclusions may be made which could influence subsequent management. It is suggested that the method of voiding should be standardised by instructing patients, if possible, to avoid abdominal straining during uroflowmetry assessment.
Meffan
P J
PJ
Department of Surgery, Wellington School of Medicine, New Zealand.
Nacey
J N
JN
Delahunt
B
B
D000005:Abdomen / Q000502:physiology*; D000328:Adult; D006801:Humans; D008297:Male; D008433:Mathematics; D011312:Pressure; D013997:Time Factors; D014556:Urine; D014563:Urodynamics / Q000502:physiology*