Uroflowmetry in normal Thai subjects.

Background And Objectives: Uroflowmetric parameters of urination may be influenced by many factors including age, sex, voiding position, technique used and also anatomical and physiological variations. A cross-sectional study was carried out to measure uroflowmetric parameters in normal Thai subjects and to compare these parameters among different ages and genders. Correlations between peak flow rate and other parameters were also studied.

Method: One hundred and forty healthy Thai subjects were studied. They were classified into two groups. Group I comprised of 50 male and 50 female young adults aged 18-30 years. Group II comprised of 20 male and 20 female pre-elderly aged 50-60 years. A Dantec Urodyn 1,000 uroflowmeter was used. The residual urine measurement was performed using an ultrasonograph.

Result: The techniques revealed the following uroflowmetric parameters. In the young adults, the mean with standard deviation of the peak flow rate was 31.2 +/- 9.0 ml/sec, mean flow rate 22.6 +/- 7.4 ml/sec, voiding time 24.7 +/- 10.6 sec, and voided volume 376.9 +/- 147.5 ml. In the pre-elderly group, the peak flow rate was 27.5 +/- 9.2 ml/sec, mean flow rate 19.1 +/- 6.2 ml/sec, voiding time 24.4 +/- 8.5 sec, and voided volume 310.3 +/- 107.8 ml. The peak flow and mean flow rates were significantly higher in the young adults (p < 0.05). The voided volume in the young was higher with similar voiding time. The peak flow and mean flow rates in females were significantly higher than the males (32.5 +/- 10.0 vs 27.8 +/- 8.0 ml/sec, p < 0.05 and 23.5 +/- 8.1 vs 19.8 +/- 5.8 ml/sec, p < 0.05 respectively). Voided volume and voiding time did not differ among both genders. The correlation between peak flow rate and voided volume was significant (r = 0.382, p < 0.01) indicating that the higher the voided volume the higher the peak flow rate. Residual urine was less than 50 ml in all subjects indicating that these subjects could void completely well. This study yielded normal uroflowmetric parameters in Thai young adult and pre-elderly subjects without urological symptoms. These parameters vary with age and gender, and are useful for the investigations of bladder function in a urological clinic.