Bladder-filling pressure

Myelomeningocele is the most common cause of the neurogenic bladder in children. Pressure volume characteristics determine the fate of the urinary tract. There are three predictive indicators for upper tract deterioration detrusor sphincter dyssynergia, high bladder-filling pressure, and poor bladder compliance. Expectant treatment can no longer be advocated. 

Fig. 16.2. Estimation of high bladder filling pressure by modified VCU. Increasing vesical pressure (Pves) i h bladder filling leads to decreasing flow and cessation of infusion flow if Pves...

Preservation of the upper urinary tract is the central goal in the treatment of neurogenic bladder in children with myelodysplasia. Predictive indicators for upper urinary-tract fate are detrusor sphincter dys-synergia, high bladder-filling pressure, poor bladder compliance, moderate to severe fibrosis of the detrusor (OzKAN et al. 2005), high leak-point pressure, and vesicoureteric reflux (Seki et al. 2004). 

Large doses of caffeine cause diuresis. Daily consumption of caffeine citrate increased the mean urinary excretion rate of tubular cells and erythrocytes in volunteers (25). The nephrotoxicity of analgesic antipyretic drug combinations may result from a combined effect, in which aspirin, phenacetin, and caffeine all play a role (SEDA-4, 5). In 10 asymptomatic women and 20 women with confirmed detrusor instability, caffeine caused a significant increase in detrusor pressure on bladder filling in the latter, but no difference in volume at first contraction, height of contraction, or bladder capacity (26). 

In a first step, bladder and sphincter function are completely evaluated urodynamically during the phases of bladder filling, storage, and voiding. Prior to instrumentation an initial uroflowmetry is performed. The urodynamic study comprises continuous monitoring of rectal pressure, sphincter electromyogram, total bladder pressure, and sub-... 

It is well known that subvesical obstruction leads to bladder hypertrophy, reduced bladder compliance and capacity, high detrusor pressure during bladder filling and voiding, and unstable detrusor contractions. Based on this well-known pathophysiological mechanism, the speculative conclusion could... 

Fig. 16.3. Estimation of poor bladder compliance by modified VCU (V bladder filling volume PyEs vesical pressure)...

Fig. 16.4. Estimation of the safe storage period (the bladder volume at which vesical pressure remains well below 40 cm H2O, the safe storage pressure) by modified VCU (Pves vesical pressure V bladder filling volume)...

A bladder or diaphragm-type aeeumulator should be supplied to provide proper lube oil supply to the bearings during expander-eompressor eoast-down in the event lube oil pressure is lost. The aeeumulator must be fitted with a preload filling system and neeessary bleed and bloek valves. 

G. Magnus found that if a glass tube is closed at the top with moist bladder, the evaporation of the water causes mercury to rise in the tube, and Leslie, with an atmometer of a porous ball filled with water at the end of a glass tube filled with water and inverted in mercury, found that as the water evaporated the mercury followed nearly to the barometric height. E. Askenasy, found that the mercury could rise much beyond the barometric height. If the partial pressure of water vapour in the outside air is p, and p is the vapour pressure of water, the pressure in the mercury column is proportional to In (p/p )- The osmotic pressure of a solution is connected with the vapour pressure lowering by the same factor. 

Uses of Butyl Ruhher. Butyl rubber is used in the manufacture of inner liners of tubeless tires, inner tubes, cable insulation, pharmaceutical stoppers, curing bags, and bladders for tire manufacture. When tires are in the molds for vulcanization, the inside of the tire is filled with a butyl rubber bag or bladder of steam under enough pressure to obtain the vulcanization temperature. This is possible only because of the good resistance of butyl rubber to heat and water. 

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