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

Abstract

Objective. The purpose of this study was to evaluate the effect of premicturitional bladder volume (V 1 ) on postvoid residual urine volume (V 2 ) measurements and to assess the ideal V 1 for an accurate V 2 determination. Methods. Twenty-five healthy men without any urinary symptoms constituted the study group. Measurements by transabdominal ultrasonography for V 1 and V 2 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 V 1 and V 2 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 V 2 , 15 (60%) men had V 2 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 V 1 of less than 540 mL had V 2 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 V 1 measurements of the bladder be performed before V 2 measurements and that V 2 not be measured if V 1 is greater than 540 mL. Key words: bladder; residual volume; ultrasonography. he accurate determination of postvoid residual urine (PVR) volume (V 2 ) is an important factor for diagnosing voiding dysfunction and for making a decision regarding the treatment options in the management of benign prostatic hyperplasia.