男子における尿道抵抗の測定

Abstract

By the use of a modified electro-magnetic uroflowmeter of our own make the instantaneous flow rate of urine was measured accurately and recorded. Simultaneously with this, a direct cystometry (suprapubic) was performed; recording was made of the intravesical pressure during emptying of the bladder and values for PB /F2 (PB : intravesical pressure at peak flow) calculated, which were considered to represent the urethral resistance. Discussions were made on the urodynamic significance of the urethral resistance PB /F2, and various questions arising as to its correct determination were also discussed. The exit pressure was neglected which was regarded as atmospheric pressure, and, an adapter was connected to the transducer of the electromagnetic uroflowmeter to neglect the effect of the vena contracta. Determinations were made of the above mentiond parameters on 33 male controls as well as 29 males with mechanical obstruction of bladder outflow. The following results were obtained. 1) For normal males the average flow rate (AFR) was 3.4~18.8 ml/sec with an average of 9.2ml/sec. The peak flow rate (PFR) ranged from 21 to 49 ml/sec, averaging 32.7 ml/sec. The peak flow pressure (PFP) was 5~62 mmHg, 30.7 mmHg on the average. The urethral resistance (R) was O.0028~O.0689, averaging 0.0313 mmHg/(ml/sec)2. 2) In the group of patients with difficult urination due to mechanical obstruction values for each of the 4 parameters were found well correlated with the severity of the disorder which was classified clinically into 4 stages according to the average amount of residual urine. The urethral resistance (R), among the said parameters, is considered to serve as an important index for the quantitative evaluation of the degree of bladder outlet obstruction, showing a particularly distinct correlation with the clinical stages of the disorder.