Abstract: PD39-08
Sources of Funding: none

Introduction

Decrease of Qmax during intubated flow (IF) in women is due to a urethral reflex (foreign material) and has over-estimation of obstruction as consequence [1]. Our hypothesis is that a similar phenomenon could occur in men. Our purpose was to search for a method using results of a free uroflow (FF) preceding an IF to eventually correct the AG number estimation

Methods

Retrospectively, analysis of 441 urodynamic studies of men suspected of bladder outlet obstruction (BOO) was performed (FF then IF catheter 8F and AG estimation)._x000D_ The VBN model [2] links urethral obstruction (counter-pressure pucp exerted by the prostate) and detrusor contractility (parameter k) to Qmax and pdet.Qmax. AG and pucp are strongly correlated [3]. Iso-contractility curves in the plane [Qmax,pdet.Qmax] are a nomogram fitted by a non-linear approximation._x000D_ Cut off value for occurrence of a urethral reflex is Qmax.FF>1.5*Qmax.IF. Using the nomogram a corrected AG (Cor_AG) was computed. All computations were made in Excel. _x000D_

Results

Nomograms were carried out and used (Figure) allowing in step 1 (from IF data) evaluation of detrusor contractility (k), then in step 2 (from FF data and k) to compute pdet.Qmax.FF and Cor_AG. A sketchy pathway for computation of Cor_AG is given in the figure. Only 362 files with Vini.FF>90 ml were included. Cor_AG was compared to AG; for example (O for AG becoming E or NO for Cor_AG)._x000D_ Results are given in table._x000D_ When Qmax.FF>1.5*Qmax.IF there was no significant difference in Vini (375±245 mL for FF vs. 410±139 mL for IF; n.s.). Increased BOO resulted from a urethral reflex during IF and AG gave an overestimation (agreement with AG was only 46.5%). An emended AG (Cor_AG) allowed a better classification of BOO._x000D_ When Qmax.FF < 1.5*Qmax.IF, Vini was significantly different (313±195 mL for FF vs. 431±154 mL for IF; p <.0001). Selection bias has been excluded. Agreement with AG was found in 72.9%._x000D_

Conclusions

To obtain a reliable evaluation of BOO in men, it is suitable to perform a FF before IF. An easily usable Excel tool allows computation of a corrected AG (Cor_AG) which value, if lower than AG, indicates the occurrence of a urethral reflex during IF. The proposed nomograms could be helpful for evaluation of BOO in men._x000D_ 1-Int Urogynecol J 2013; 24: 461-7; 2-NAU 2000; 19:153-76; 3- Ann. Readap. Med. Phys. 2005 ; 48 :11-19._x000D_

Funding

none