From Big Medical Encyclopedia

URODYNAMIC (Greek uron wetting + dynamikos relating to force power) — process of active removal of urine of an organism as a result of coordinate activity of the neuromuscular device of cups, a renal pelvis, ureters, a bladder and an urethra.

Release of urine from channels of renal nipples in a pelvis (see Kidneys) is carried out under the influence of two factors — secretory pressure in the canalicular device of a kidney, equal 36,7 — 51,5 mm of mercury., and two-phase activity of cups.

When muscles of a cup are relaxed (the first diastolic phase proceeding on average 4 sec.), urine is emitted from a channel of a renal nipple at the expense of a pressure gradient in the canalicular device and a cup. At this time the sphincter of a cup is in the closed state that prevents flowing of urine in it from a pelvis. After filling of a cup with urine the second comes, systolic, the phase proceeding 3 sec. In this phase there is a reduction of m. recludor calycis, t. levator fornicis, a sphincter of the arch and sphincteri incontinence of a cup, m. Ion - gitudinalis calycis therefore wetting iod pressure of 7,35 L1M hg moves to a renal pelvis.

The mechanism of movement of urine from a renal pelvis on ureters (see) in a bladder it is definitely not established. There are two theories of transport of urine on an ureter — so-called tsistoidny and peristaltic. According to the pistoidny theory, upper uric ways consist of lokhanochny and 2 — 4 ureteric dynamic sections — tsistoid, to-rye interact on the «pushing out — locking» type. In the first tsistoid the role of a detruzor (the expelling muscle) is carried out by a pelvis, a role of a sphincter (occlusor) — a lokhanochno-ureteric segment. In an ureter detruzory each dynamic section the respective site of an ureter, a sphincter — kavernoznopodobny vascular educations is. Consecutive reduction overlying and relaxation of underlying tsistoid provides gradual advance of a portion of urine in a bladder.

The peristaltic theory denies existence of tsistoid and explains process of a mochevyvedeniye with peristaltic activity of an ureter, edges depends on a diuresis (see). At a small diuresis (to 3 — 4 ml! mines!

1,73 sq.m of a body surface) the discrete type of a mochevyvedeniye takes place, to-ry it is carried out as follows. Accumulation of urine in a pelvis is followed by build-up of pressure in it. When pressure reaches a critical level (10 — 12 cm w.g.), there is an opening and filling with urine of a lokhanochno-ureteric segment. The stretching of walls of a segment arising at the same time generates a peristaltic wave, edges extends on an ureter in the distal direction with a speed of 4,5 cm! sec. is also followed by consecutive rise to 18 — 40 cm w.g. pressure on the course of the channel of an ureter. This process also causes advance of a separate portion of urine on urine -

a tochyika. Frequency of following of peristaltic waves makes

2 — 6 in 1 min. Transition to perfused type of a mochevyvedeniye happens at a diuresis of St. 3 — 4 ml/min. / 1,73 sq.m of a body surface. At the same time the evacuated portions of urine merge, and the renal pelvis, an ureter and a bladder are freely reported among themselves. The perfused type of a mochevyvedeniye is carried out at the expense of a pressure gradient in top and bottom uric ways. Pressure in the channel of an ureter reaches at the same time 40 cm w.g. and more. Speed of transition from discrete to perfused type of a mochevyvedeniye under the influence of water loading or diuretics is used for assessment of a functional condition of upper uric ways.

The urodynamic of a bladder (see) and an urethra (see) is characterized by two phases. In the first phase there is an accumulation of urine in a bladder up to the threshold volume of 200 — 400 ml at low (10 — 15 cm w.g.) intravesical and high (80 — 90 cm w.g.) intra urethral pressure. Low intravesical pressure is connected with adaptation (relaxation) of a detruzor whereas high intra urethral pressure is created by reduction smooth muscle internal and cross-striped outside sphincters, a tone of muscles of an urethra and a bottom of a basin. The negative vesical and urethral pressure gradient provides deduction of urine in a bladder.

Achievement of threshold volume, i.e. volume, at Krom comes an urination (see), is followed by exhaustion of adaptation of a detruzor and increase of its muscular tension. It leads to increase in intravesical pressure and at the same time to relaxation of sphincters of an urethra. There comes the second phase U. — bladder emptying and evacuation of urine in an urethra. The sphygmic phase is estimated on indicators of miktsionny pressure (pressure in a bladder during the act of an urination), flow rates of urine and to resistance in an urethra.

Miktsionny pressure characterizes force of reduction of a detruzor and fluctuates within 50 — 85 cm w.g. It does not depend on the initial volume of a bladder and age of the patient.

The most available to definition and the analysis the characteristic of a flow of urine is rate of volume flow. This indicator is in direct dependence on amount of in one step emitted urine: at the volume up to 200 ml volumetric flow rate makes 14 — 24 ml/sec., at the volume more than 200 ml — 25 — 35 ml/sec.

Volumetric flow rate of urine is regulated by the functional section of an urethra, a cut, in turn, depends on the muscular tension of a detruzor: the more the initial volume of a bladder, the is higher the muscular tension of a detruzor and consequently, both the effective section of an urethra and volumetric flow rate of urine is more. Miktsionny pressure has no significant effect on volumetric flow rate of urine.

To the most important indicators At. sphygmic phases resistance in an urethra reflecting power loss by a flow of urine at its passing through an urethra belongs. Power loss depends on length, diameter, roughnesses of the channel, viscosity of urine, turbulence of a flow and, according to Gleason (D. M of Gleason, 1976), makes 50 — 70% at men and women have 30 — 50%.

In 1976 S. Ryabin a cue and

V. F. Savin for the characteristic At. the lower uric ways of a sphygmic phase offered one more indicator — power efficiency of an urination, or efficiency of an urination, to-ry represents the relation of pressure of a stream of the let-out urine to miktsionny pressure. At patients hron. pyelonephritis without obstructions of uric ways the efficiency of an urination fluctuates from 39 to 64%.

Frequent disturbance At. at diseases of urinogenital bodies the reversed current of urine is (see the Reflux). At substantial and sudden increase of intrapelvic pressure, and also at patol. changes of the arch of cups there are lokhanochno-renal refluxes — the return flowing of contents of a pelvis in a parenchyma of kidneys with its subsequent penetration in venous or limf. network. Lokhanochno-pochechnye refluxes play an important role in a pathogeny of inflammatory diseases of kidneys, can be the reason of resorptive fever and acute pyelonephritis.

The vesicoureteral reflux can be inborn and acquired (secondary). Emergence in r about and v d e other p at z yr in N about - urine that chn to about - a vy reflux is caused by a malformation of a muscular layer of terminal department of an ureter. The secondary

11 bonds y r but - ureters y y ref l yuks

arise at the diseases breaking a passage of urine from a bladder and a tone of its muscular wall — a sclerosis of a neck of a bladder, a stricture of an urethra, cystitis, tuberculosis of a bladder, adenoma and a prostate cancer, etc.

The heaviest disturbances At. develop at obstacles to current of urine but the course of uric ways in connection with existence of stones, valves, cicatricial narrowings, tumors, additional vessels, etc., to-rye most often meet in lokhanochno-ureteric, vesicoureteral and vesical and urethral segments. At emergence of an obstacle to current of urine at the level of lokhanochno-ureteric and vesicoureteral segments a sign of frustration At. gradation on irreversible perfused type of a mochevyvedeniye is. It is shown by increase in capacity of the departments of uric ways located above an obstacle, increase in hydrostatic pressure in them, oppression of sokratitelny activity of smooth muscles. Emergence of an obstacle in the level of a vesical and urethral segment is followed by increase in resistance in an urethra. On this background there are secondary structurally functional changes of a detruzor having three stages of development: functional disturbances, compensation and decompensation. The stage of functional disturbances is characterized by the standard miktsion-ny atmosphere pressure and low volumetric flow rate of urine; a stage of compensation — the increased mik-tsionny pressure and normal volumetric flow rate; a stage of a decompensation — the increased megapixel to c ionic pressure due to inclusion of extracystic forces of emptying (a muscle tension of a front abdominal wall) and low volumetric flow rate of urine.

Research U. upper uric ways carry out by means of excretory urography (see), a television piyeloureteroskopiya (sighting on the screen of the TV of dynamics of contrasting of an ureter and band system of a kidney), a radio isotope renografiya (see Renog a raffia radio isotope), urete-romanometriya (see Catheterization of uric ways), elektrouretero-grafiya (see the Ureter, methods of a research). For a research U. the lower uric ways to a phase of accumulation of urine apply a retrograde tsistometriya (see the Bladder), an electromyography of urethral and proctal sphincters (see Elek tr ohm of yogas a raffia), p a rofilometriya of an urethra (graphic registration of pressure throughout all urethral dripped). The phase of an otto-rozhneniye of a bladder is estimated by methods of a direct tsistometriya, an urofloumetriya (see), an electromyography of urethral and proctal sphincters.

Bibliogrderzhavin V. M., etc. Urodynamic of upper uric ways at a vesicoureteral reflux at children, Urol. and nefrol., N ° 2, page 11, 1982; Pytel A. Ya. Lokhanochno-pochechnye refluxes and their clinical value, M., 1959; Ryab both a certain V. S. and Savin V. F. Urodinamofloumetriya at diseases of the lower uric ways at men, Urol. and nefrol., N 1, page 34, 1976; Boyarsky S. a. Laba at R. of Principles of ureteral physiology, in book: The ureter, ed. by H. Bergman, p. 71, N. Y. a. o., 1981; Campbell W. A, Interpretation of pediatric urodynamics through bladder work calculation, J. Urol., (Baltimore), v. 94, p. 112, 1965; Gleason D. M, In o t t and with with i n i M. R. as D r a with h G. W. Urodynamics, ibid., v. 115, p. 356, 1976; Rankin J. T, Concepts of urethral resistance, Brit. J.; Urol., v. 39, p. 594, 1967.

V. M. Derzhavin, E. JI. Vishnevsky.