1984 Volume 75 Issue 12 Pages 1964-1969
Recorded data show that males with obstructive diseases of the lower urinaly tract have low voided volume. Comparisons of flowrates between normal males and those with obstructive diseases are difficult because Maximum Flow Rate (MFR) and Average Flow Rate (AFR) increase proportionately with voided volume, especially when voided volume is below 200-300ml.
We developed a new parameter of Uroflowmetry which has been designated as MFR/Voided Time (MIT). Using MFR, AFR and M/T, we compared uroflowmetric studies between two groups: 30 normal males (160 studies); and 141 males with obstructive diseases (228 studies). In the latter group, 186 studies (82%) were with voided volume less than 200ml.
The results were as follows.
1) MFR and AFR in both groups increased proportionately with voided volume below 200ml.
2) MFR and AFR in normal males were almost constant with voided volume over 200ml.
3) MFR and AFR in males with obstructive diseases increased proportionately with voided volume over 200ml. The correlations between the two parameters (MFR or AFR) and voided volume were significant in patients with voided volume below 200ml. These correlations became significantly less in those with a voided volume over 200ml.
4) In a voided volume of 4 to 688ml, normal male M/T ranged from 0.58 to 3.90 (1.50±0.57), and in males with obstructive diseases the range was from 0.01 to 0.76 (0.23±0.16).
5) The correlation between M/T and voided volume in males with obstructive diseases was not significant, regardless whether the voided volume was below or above 200ml.
6) In analysing the number of overlap uroflowmetries in both groups, we found M/T to be statistically more selective than either MFR or AFR. Moreover, M/T was almost constant in males with obstructive diseases.
We found M/T to be the preferable parameter in the uroflowmetric study of low voiding males with obstructive diseases of the lower urinaly tract.
