Uroflowmetric differences standing and sitting positions for men used to void in the sitting position

ABSTRACT

Uroflowmetry test should be done in situations approximating the natural voiding act to get results reflecting the true state of voiding function. In many countries, men are accustomed to void in the sitting position due to ritual or religious causes. Carrying out this test in the standing position in such people might produce false results. To compare the results of uroflowmetry in the standing and sitting position in men who are accustomed to void only in the sitting position with respect to age and degree of obstruction. Two hundred patients were enrolled in this study. A detailed medical history was taken in addition to routine physical examination including DRE. All of them were complaining of lower urinary tract symptoms. All patients were subjected to pelvic uitrasonography while bladder is full to evaluate bladder capacity, exclude any bladder pathology like stones or masses and assess prostatic size and echogenicity. Their age ranged from 18 to 90 years [median =50.5, mean +/- SD = 51.85 +/- 14.48 years]. Patients were asked to urinate without increasing the abdominal pressure in both standing and sitting positions. The test was done in the sitting position first followed by the standing position in 100 patients and in the standing followed by the sitting in the other 100 patients to nullify the [after effect] or the [learning effect]. Each test was repeated in the same position twice therefore we had 800 uroflowmetry tests. Post-voiding residual urine was estimated ultrasonographically. Comparisons were made between both positions uroflowmetric tests for all patients, then further comparisons were made according to patients' age [below and above 50] and Qmax [at or below15 ml/second versus >15 ml/second]. Statistical analysis was done using Wilcoxon matched-pairs Signed-Ranks test. Comparison of uroflowmetric results in both positions showed no statistical differences except for significantly larger residual urine volume in the standing position [86.1 +/- 77] relative to sitting position [73 +/- 80.2] [P=0.04]. Substratifying patients according to age was done [<50 and >50 years]. In the first [young] group, Qmax was significantly higher in the sitting position [16.6 +/- 8.94] relative to the standing position [15.2 +/- 7.5] [P=0.02]. Such significant difference was not seen in the latter [>50 years] group. Moreover we substratified the patients according to Qmax into obstructed [<15 ml/second] and non-obstructed [> 15 ml/second]. In the obstructed group, no significant differences were observed between both positions' uroflowmetric parameters. On the contrary, in the non-obstructed group ,there were significantly higher Qmax and Qave, significantly lower voiding and flow times and significantly lower residuai urine volume in the sitting position, Voiding in the sitting position showed significantly better flow rates than during standing in non-obstructed and younger patients. Moreover, PVR was significantly less in the same groups of patients and in the total group of patients. On the contrary the presence of infravesical obstruction nullifies these differences of uroflowmetry in the sitting and standing positions. Uroflowmetry should be always performed in the preferred position. Further studies with concomitant intra-abdominal pressure and EMG recording should be performed to properly understand the physiologic impact of different positions on the micturition act