Uroflowmetry

Uroflowmetry - record speed of the flow of urine in natural conditions urination reflects evaquatornuu the bladder. Urine flow rate is determined by the amount of urine per unit of time (ml/s). Graphically uroflowmetric curve in norm is of the form "the bells" and consists of continuously consecutive upstream and downstream segments, the United rounded tops. The development of urination accompanied by a rise urologichsky to the peak of the curve corresponding to the maximum flow rate of urination. In the field of small area corresponding to the top uroflowmetric curve remains stable urine flow rate, and then curve slow down to zero. At the end of the descending segment has repeated a small peak of the curve corresponding to the release of the last portion of urine. Evaluation of the results of uroflowmetry is based on the indicators of maximum and average flow rate of flow of urine, the ratio of the amount of urine and the flow rate of urination, the total duration of urination and the time of maximum volume rate of flow of urine. There is a positive correlation between the duration of urination and the amount of urine. The normal duration of urination - the period of time during which you are recording speed of the flow of urine,amounts to 10 - 20 C in the amount of 100 ml urine Duration urine increases to 23 - 25 if you increase the amount of urine up to 400 g Along with the total duration of urination distinguish the time required to reach maximum values of volumetric speed of urination, which is 1/3 of the total duration of urination. The amount of urine in a single urine varies from a few milliliters up to 800 ml or more. On average, the amount of urine is 250+ Maximum 100 ml volumetric rate of urination is the most informative indicator. In norm at men its value fluctuates between 18 - 30 ml/s Values within 10-14 ml/s reflect the lower, and below 10 ml/s - a sharp decrease in the rate of flow of urine. The average flow rate of urination is determined by the ratio of the amount of urine and the total duration of urination (the normal average of 15.7 ml/s). There is a positive correlation between the maximum volumetric speed of urination and the amount of urine. The peak maximum flow rate increases urination, accordingly, to increase the amount of urine. Such a pattern is more clearly seen in normal physiological condition evacuation of the mechanism of the bladder, than for dysfunction of the urinary tract. So, under normal conditions of urination value of maximum flow rate of urination increased by 2.5 ml/s when allocating 100 ml of urine, and in a broken evacuation function of the bladder is only 1.6 ml/s when allocating the same amount of urine. Assessment of the amount of urine as one of the indicators of uroflowmetry increases the sensitivity of this test and allows to differentiate normal urination from disturbed.
The most accurate data on maximum flow rate of urination can be obtained in the amount of urine from 200 to 400 ml In the amount of urine below 150 - 200 ml decreases the accuracy of determining the maximum volume rate of flow of urine. It is observed in severe degree infravesical obstruction in connection with the development of benign prostatic hyperplasia, which is a small amount of urine. Uroflowmetry is used as a primary screening test to detect obstruction in the gallbladder-urethral segment with growth of adenomatous nodes. Characteristically reshaping uroflowmetric curve that is flattened due to lower the maximum flow rate of urination and increased total duration of urination. In some cases, the development of obstacles to the flow of urine in the field of cystic-urethral segment uroflowmetric curve becomes intermittent with "emissions" small amounts of urine, and lengthening of the total duration of urination up to 30 C at a maximum flow rate of urination 5 ml/S. the decrease in the values of the maximum and average flow rate of urination in men older, presenting complaints of frequent urination, nictoria, with a high degree of probability reflects the development infravesical obstruction, but does not reveal its causes. Reduction of the maximum and average flow rate of urination may be causally associated not only with the development of obstacles to the flow of urine in the lower urinary tract. Those declines are also occurs when diverticula bladder, vesicoureteral-reflux primary bladder dysfunction. At the same time, the maximum volume flow rate of urine less than 10 ml/s at the amount of urine 150 - 200 ml and determined by palpation adenoma of the prostate by rectal examination indicates infravesical obstruction, causally associated with the disease. The probability infravesical obstruction declines in the values of the maximum volume flow rate of urine within 12-15 ml/s and at a maximum flow rate of urination more than 15 ml/s is rare.
According to the configuration uroflowmetric curve you Can get more information about detrusor instability and tension of the muscles of the abdominal wall. In such cases appear irregular waves of different levels, reflecting the reduction of the detrusor in combination with the tension of the abdominal muscles. The detrusor instability in the phase of accumulation of urine observed in 45 % of patients with infravesical obstruction caused by the growth of adenomatous nodes. Timely detection of detrusor instability in patients with prostate adenoma is of practical importance, as this is much worse functional results of adenomektomii. When infravesical obstruction due to prostatic gradually reduced contractility of the detrusor, due to the violation of the mechanism of adaptation of the urinary bladder to the new conditions of urodynamics. In the initial stage of development infravesical obstruction hypertrophy detrusor ensures the preservation of the evacuation function of the bladder, which is confirmed by the normal values of the maximum and average flow rate of urination. In the future, with the development of trabekuliarnae of the bladder wall is reduced contractility of the detrusor and reduced the maximum volume flow rate of urine. This uroflowmetric curve becomes wavy intermittent form, so as to create high intravesical pressure needed to overcome barriers to the flow of urine in the bladder-urethral segment are included contraction of the muscles of the abdominal and pelvic diaphragm.


Infravesical obstruction is accompanied by frequent urination with the release of small amounts of urine. In this connection there was a necessity of correction figure a maximum flow rate of urine in accordance with the amount of urine that is informative indicator only in the amount exceeding 150 ml For
increase the information value of the indicator of the maximum flow rate urinating in the diagnosis infravesical obstruction developed nomograms, which on the basis of statistical processing of a large number of studies graphically shows the distribution of the maximum and average flow rate in the amount from 50 to 500 ml [Siroky M. et al., 1979]. Using nomograms can establish the relationship between flow rate and volume of leakage of urine. Nomograms allow to define the lower limit of normal maximum values of volumetric speed of urination (<15 ml/s) with a small amount of urine (<100 ml). For comparison, the speed of the flow of urine amount of urine these values translate into units of nomograms - standard deviation. In the absence of barriers to the flow of urine units nomograms exceed -2 standard deviations. Development infravesical obstruction is accompanied by a reduction units nomograms (below 2 standard deviations). These nomograms can be used also for determination of resistance locking mechanism of the urethra. The value in use of nomograms is the ability of the analysis of maximum and average flow rate of urination during their variability in relation to the amount of urine.
Infravesical obstruction 60% of patients with adenoma prostate gland is accompanied with detrusor hyperreflexia with a decrease in the amount of urine (less than 200 ml). In such cases, using nomograms can be set urine flow rate is less than the 9.5 ml/S. Thus, the considerable variability of maximum and average flow rate of urination when infravesical obstruction complicates interpretation uroflowmetric indicators. In such cases, the use of nomograms, reflecting the relationship between the maximum and average values of volumetric speed of urination, allows you to diagnose infravesical obstruction. Nomograms speed of the flow of urine can be used not only for diagnostic infravesical obstruction, but also to assess the effectiveness of treatment, which is especially important when the combination of benign prostatic hyperplasia with stricture of the urethra. Increase of the maximum flow rate of urination after adenomektomii and expansion of the urethra indicates an improvement in urodynamics and conservation units nomograms below -2 standard deviations gives the basis to diagnose residual effects of obstruction.
In evaluating the performance of uroflowmetry there is a problem of definition of influence of residual urine in the value of the maximum flow rate of urination. This is done using a mathematical correction index of maximum urinary flow rates, which it is calculated by dividing by the square root of the total volume of urine in the bladder (the amount of urine + residual urine). It is necessary to have information about the amount of residual urine, the value of which varies significantly with obstruction in the gallbladder-urethral segment and detruzora of hyperreflexia, which reduces the accuracy of determining the values of the maximum flow rate of urination. In patients with prostate adenoma cancer to adenomektomii not observed positive correlation between maximum speed urination and the total volume of urine in the bladder. This is explained by the negative relationship between the values of the maximum flow rate of urine and the amount of residual urine, i.e. the greater the volume of residual urine, the lower the maximum volumetric speed of its flow. With little residual urine volume according to the excretory urographine or cystourethrography the amount of urine, with sufficient reliability reflects evaquatornuu the bladder. Using nomograms flow rate with a high degree of probability can be identified intravesically obstruction when using the indicator of the amount of urine that eliminates catheterization bladder when the available data on the presence of residual urine. To catheterization bladder for determination of residual urine after uroflowmetry resorted to only in cases when there are clinical symptoms infravesical obstruction, and indicators of maximum flow rate of urination are within bordering the norm. Determination of the total volume of urine in the bladder is advisable for alleged large volume of residual urine (more than 100 ml) and the values of the maximum speed urinating less than 10 ml/s, which reflects a pronounced degree of urination disorders associated with dysfunction of the detrusor, infravesical obstruction and substantial increase intravesical pressure. The indicators of maximum flow rate of urination most accurately reflect urination disorders associated with infravesical obstruction, compared to other uroflowmetric indicators (average flow rate of urination, the time to reach peak maximum volume rate of flow of urine). The reduction of the maximum flow rate of urination is positively correlated with clinical symptoms of obstruction - frequent and difficult urination, imperative urge, nictoria.
So, uroflowmetry is informative method of determining the speed of the flow of urine, characterizing evaquatornuu the bladder. Using this study, you can identify infravesical obstruction. For its diagnosis at early stages of development in patients with prostate adenoma data volume rate of flow of urine should be complemented by measuring intravesical pressure to obtain information on the amount be resistance. Urodynamic testing may be conducted simultaneously with the entry intravesical, abdominal pressure, the sphincter electromyography, registration profile urethral pressure.