Effect of Premicturitional Bladder Volume on the Accuracy of Postvoid Residual Urine Volume Measurement by Transabdominal Ultrasonography

摘要

Objective. The purpose of this study was to evaluate the effect of premicturitional bladder volume (V1) on postvoid residual urine volume (V2) measurements and to assess the ideal V1 for an accurate V2 determination. Methods. Twenty-five healthy men without any urinary symptoms constituted the study group. Measurements by transabdominal ultrasonography for V1 and V2 were performed for each subject at 3 different phases, each of which was preceded by oral intake of 1000 mL of water and accompanied by “mild,” “moderate,” and “severe” sensations of micturition, respectively. Results. Mean ± SD V1 and V2 during the first, second, and third phases were 117.7 ± 70.3 and 1 ± 1, 356.2 ± 112.3 and 11.5 ± 12 and 639.6 ± 171.8 and 58.8 ± 35.2 mL, respectively. With 50 mL as the cutoff value for a pathologic V2, 15 (60%) men had V2 in the third phase exceeding this value, whereas the same rate was calculated as 0% for either of the first 2 phases. No patient with V1 of less than 540 mL had V2 of greater than 50 mL. Conclusions. Postvoid residual urine volume measurements with an uncomfortably full bladder result in high false-positive postmicturitional residue values even in healthy young men. We strongly advise that V1 measurements of the bladder be performed before V2 measurements and that V2 not be measured if V1 is greater than 540 mL.