Correlation Analysis Between Maximum Urinary Flow Rate And Voided Volume In Healthy Young Men

Background Uroflowmetry is one of the preliminary measurement methods for lower urinary tract dysfunction in patients with Lower Urinary Tract Symptoms（LUTS）.It is more acceptable because of its non-invasive,easy to operate and more economical features.LUTS is a common urinary system problem in men,including storage symptoms,voiding symptoms and post-urination symptoms.LUTS produces additional psychological pressure and economic burden,which seriously affects people’s quality of life[1].Domestic research on urodynamics started late,and the normal reference values currently used are mostly from foreign research data,and most scholars prefer disease-related research,and research on healthy people,especially young people,is very scarce.LUTD is also common among young men in my country[2].At present,the maximum value in uroflowmetry（UFM）is the maximum urine flow rate（Qmax）,which is mainly used in clinical practice to evaluate the results of the urine flow rate test.ICS recommends that when the urine output is150-400 ml,the minimum value of Qmax for adult males is 15ml/s,and the reference value is also used as an evaluation index for judging urinary tract obstruction in textbooks.However,in long-term clinical practice,it is found that the current use of Qmax<15ml/s to evaluate the results of uroflowmetry in patients with LUST seems to be too conservative,and there have been domestic reports on the uroflow rate and voided volume（VV）in healthy middle-aged and elderly men[3-4],To this end,this study analyzed the relevant data of uroflowmetry in healthy young men.While filling the relevant data gaps in this age group,it also provided some reference for clinicians’ diagnosis and prognosis evaluation of patients.Objective To understand the changing trend of maximum urine flow rate,average urine flow rate and 2s urine flow rate of healthy young men under different voided volume.Methods During the period from November 2020 to December 2020,500 young men without abnormal urination were recruited at Xinxiang Medical University and the First Affiliated Hospital of Xinxiang Medical University.The free urine flow rate was measured in the toilet after drinking 500-1000 ml pure water.The voided volume,maximum urine flow rate,average urine flow rate（Qave）,urine flow rate at 2 seconds,voiding time and urine flow time were recorded by mobile household electronic urine flow meter（XYS.WRM-2PN）.The urine flow was divided into 7 groups: group A（VV<100ml） G（VV≥600ml）.Qmax,Qave and urine flow rate at 2 seconds were compared between the different groups.Results The maximum urine flow rate of the seven groups was 13.29 ±3.86,21.65 ±5.84,25.60 ±6.21,27.82 ±6.52,31.92 ±6.47,32.35 ±6.59,respectively,and the average urine flow rate of the seven groups was 6.34 ±1.75,10.51 ±2.34,13.57 ±2.80,14.93 ±3.03,18.05 ±3.66,18.22 ±3.45,18.26 ±2.43,respectively.The urine flow rate at 2 seconds was9.05 ±4.40,13.54 ±5.92,14.22 ±6.98,13.85 ±6.37,18.93 ±6.14,18.69 ±6.32,15.95 ±4.98,respectively.When the urine flow was less than 500 ml,the maximum urine flow rate,the average urine flow rate,and the urine flow rate at 2 seconds all increased with the increase of urine flow,and the differences among different urine flow groups were statistically significant（P < 0.05）.Conclusion The maximum urinary flow rate of healthy men in this age group was positively correlated with voided volume when the voided volume was less than 500 ml,and remained relatively stable when the voided volume was between 200 and 500 ml.For the maximum urine flow rate at any given voided volume within the voided volume range,the normal probability can be judged by the Siroky nomogram.