Hypothesis / aims of study
Acute urinary retention (AUR) is a common urological emergency associated with painful inability to void urine. Urethral catheterization is an immediate management of AUR for bladder decompression. Trial without catheter (TWOC) is a standard management for patients. In most cases, an α1-blocker was prescribed before TWOC and it showed signiﬁcantly increases the chance of success. However, repeat catheterization would be done if TWOC is failure and complications could be occurred if frequent catheterization. For voiding difficulty, we may arrange pressure flow study (PFS) to evaluate bladder function and bladder outlet. It recorded bladder capacity, compliance, flow rate and detrusor pressure, etc. Therefore, we want to know does urodynamic study have benefit in patients with acute urinary retention.
Study design, materials and methods
We prospectively recruited patients with AUR in single institute from April 2018 to March 2019. Those patients under bed-ridden status, especially in the occasion of being incapable of standing or sitting for urination, were not included. In addition, the patients received partial cystectomy or had the diagnosis of bladder cancer were excluded. Medication, such as α1-blocker or bethanechol, could be prescribed for patients by doctors' preference. Each patient received pressure flow study on 7th day after acute urinary retention, and then the patients’ Foley catheter were kept removal after examinations. We define re-catheterization within 7 days after PFS as TWOC failure. The patients’ demographic data, questionnaires, including international prostate symptoms score (IPSS), OAB-6, overactive bladder symptoms score (OABSS), managements of AUR and the results of PFS were recorded and analyzed. Male bladder outlet obstruction (BOO) was defined as a BOO-index (BOOI) > 40 or prostate size larger than 30cc. Female BOO was defined as Pdet > 20 cmH2O and Qmax < 12 ml/sec. Categorical variables were compared by the chi-square and continuous variables were compared by the student’ t test. P < 0.05 was considered statistically significant.
In our research, totally 88 patients were included for analysis. Thirty-nine patients (44.3%) had successful TWOC (Group I) and 49 patients were failure (Group II). The mean age was 76.0 ± 10.8 years old and man accounted 67%. The average IPSS scores were 18.3 ± 9.1. Voiding symptoms were higher than storage symptoms (10.0 ± 5.9 vs 8.25 ± 4.4). The average UDI-6 and OABSS were 10.7 ± 7.3 and 8.0 ± 4.5, respectively. There was no difference in demographic data, underlying disease, questionnaire, and medications usage. Although there were no statistically significant difference in volume of first desire (114.6 vs 93.6ml, p=0.639) and cystometric bladder capacity (181.6 vs 199.4ml, p=0.80) in PFS report, acontractile detrusor was significant high in patients with failed TWOC (53.1% vs 12.8%, p=0.000). Poor bladder compliance showed no difference among two groups (23.1% vs 30.6%, p=0.0430). Maximum flow rate and mean detrusor pressure at maximum ﬂow both revealed higher in group I (36.5 vs 14.2 cmH2O, p=0.047 and 7.2 vs 1.2 ml/sec, p=0.000). There was 26 men and 9 women had bladder outlet obstruction. In man, 93.2% patients took α1-blocker after AUR. Subgroup analysis in man’s group showed the median prostate size was 63.5 ± 44.3 cm3 versus 64.3 ± 41.6 cm3, p=0.950, among two groups. Male bladder outlet obstruction was higher in group II (24% vs 58.8%, p=0.008). However, intravesical protrusion of prostate didn’t showed significant difference. (48% vs 70.6%, p=0.079).
Interpretation of results
In patients with acute urinary retention, we can evaluate bladder detrusor function by pressure flow study to avoid repeat catheterization due to TWOC failure. Acontractile detrusor had significant high in patient with failed TWOC than others. Besides, some literature recommend that α1-blocker had benefit in man with AUR but our study showed no significant difference.