Correlation Of Detrusor Function With The Post Voiding Residual Urine In Patients With BPH

Objective:A analysis was conducted in patients with lower urinary tract symptoms suggestive of benign prostatic hyperplasia to examine the relationship between the postvoid residual urine volume(PVR) and various clinical characteristics and to assess the effect of detrusor contractility and bladder outlet obstruction on PVR volume.Methods:57 patients,52 to 84 years old,with a PVR volume 10 and 210ml(mean69.7ml) were evaluated with urodynamics(free uroflowmetry,filling cystometry,pressure-flow studies,isometric detrusor pressures which was performed by gently occluding the bladder neck with a balloon catheter before and during a detrusor contraction) . The PVR volume were measured by catheterization and the difference between the influsion bladder capacity and the voiding volume.The relationships between the PVR volume and patient age,international prostatic symptoms score(IPSS),free maximum flow rate(Qmaxf),and prostate volume(Vp) were assessed.The effect of detrusor contractility and bladder outlet obstruction(BOO) on the PVR volume was evaluated. Results:Fifty-seven patients with BPH were included in this study 35(61.4%) patients with BPH diagnosed routinely had bladder outlet obstruction(BOO) and 22(38.6%) had no BOO.No statistically significant differences of PVR were observed between the two groups. In 57 patients with BPH, 22(38.6%)patients had impaired detrusor contractility while 35(61.4%)patients were normal detrusor contractility.PVR in patients with impaired detrusor contractility were more than with normal detrusor contractility(p<0.01).There was significant differences of PVR between the patients with or without the impaired detrusor contractility in BOO (p<0.01),similarly PVR between patients with or without impaired detrusor contractility in non-BOO were significant differences.Analysis of PVR in 57 BPH showed that 29.6%(8/27) of patients with PVR≥60ml,did not have obstruction ,while 53.3%(16/30)with PVR<60ml had obstruction of varying degrees.The PVR volume was not related to age,IPSS ,Qmaxf, prostate volume or the severity of bladder outlet obstruction(p>0.05).Conclusions:The post voiding residual urine volume are significantly correlated with the impaired detrusor contractility while there is no any significant differences of PVR between the patients with or without BOO . The PVR volume was not related to age,IPSS,prostate volume or free maximal flow rate.These observations indicate that the PVR volume cannot discriminate obstructed from nonobstructed BPH cases,not all BPH patients with PVR≥60ml will have outlet obstruction,a significant proportion of BPH patients with PVR<60ml can have outlet obstruction.