OBJECTIVETo investigate the effects of transurethral catheterization on the uroflow rate in the pressure-flow study of patients with benign prostatic hyperplasia (BPH).

METHODSThirty-nine men with BPH underwent free uroflowmetry and pressure-flow analysis respectively. With an 8 F urethral catheter, the standard pressure-flow variables such as the maximum flow rate, detrusor pressure at the maximum flow rate and so on were recorded. The free maximum flow rate and the maximum flow rate with transurethral catheterization were statistically analyzed.

RESULTSThe maximum voided volumes of the free uroflowmetry group and the pressure-flow study group were (209.23 +/- 56. 56) ml and (210.33 +/- 62.02) ml respectively (P > 0.05). The free maximum flow rate was (8.61 +/- 2.80) ml/s, and the maximum flow rate with transurethral catheterization-was (7.39 +/- 3.01) ml/s (P < 0.05). When the patients were divided into seven grades of bladder outlet obstruction (BOO) according to the Schäfer nomogram, the free maximum flow rate and the maximum flow rate with transurethral catheterization with Grade 0-I of BOO were (12.56 +/- 1.57) ml/s and (10.95 +/- 2.51) ml/s, and those of Grade II were (9.35 +/- 0.76) ml/s and (8.41 +/- 1.23) ml/s respectively. For Grades III, IV and V-VI , the two maximum flow rates were (7.88 +/- 1.21) ml/s and (6.37 +/- 0.59) ml/s, (6.54 +/- 1.93) ml/s and (5.55 +/- 2.48) ml/s, and (6.01 +/- 2.10) ml/s and (4.84 +/- 2.89) ml/s, respectively, all with significant difference in between (P < 0.05).

CONCLUSIONThe 8 F urethral catheter has a significant effect on the maximum uroflow rate in the pressure-flow study and this effect is correlated with the grade of BOO.