Assessment of urodynamic bladder behavior on filling with solutions representing physiological extremes of urinary osmolarity.

OBJECTIVE Verify if there is any difference in sensitive and motor bladder response in the presence of solutions with different osmolarities, simulating physiological extremes of urinary osmolarity. MATERIALS AND METHODS Thirty-three patients (24 men and 9 women) with mean age of 46.4 years (8 to 87 years) took part in this study. They were all subjected to 2 consecutive urodynamic examinations. In each exam, the vesical filling was accomplished by using a hyperosmolar (1000 mOsm/L) or hypo-osmolar (100 mOsm/L) sodium chloride solution in similar speed. The sequence in which each solution was instilled was determined by a double blind draw. The urodynamic results obtained from the infusion of both solutions were compared, regardless the sequence of administration. RESULTS Fifteen patients (45.4%) showed detrusor hyperactivity, 12 of whom with neurological antecedents. The mean age of those with detrusor hyperactivity was 45.8 years, against 46.9 for those without hyperactivity. The infusion of the hyperosmolar/hypo-osmolar solution generated the following results, when comparing patients without vs. with detrusor hyperactivity: initial sensation of vesical filling (mL): 167.5/159.2 vs. 134.9/157.3 (p > 0.05); volume of occurrence of the first involuntary bladder contraction (mL): 163.9/151.9 (p > 0.05); detrusor micturition pressure (cm H2O): 24.0/24.4 vs. 13.8/27.5 (p > 0.05). CONCLUSION The vesical filling with solutions simulating extreme urinary osmolarities, accomplished with similar speed and without previous identification, did not likewise alter the sensitive and motor urodynamic behavior in the current study.