Posterior Urethral Valves: Primary Voiding Pressures and Kidney Function in Infants
ABSTRACT We evaluated whether high voiding pressures in patients with posterior urethral valves are associated with reduced kidney function.
A total of 25 children younger than 12 months with posterior urethral valves underwent urodynamic evaluation within 15 days of valve ablation between 1994 and 2007. Six patients underwent primary urodynamics before and 19 after valve ablation. A total of 17 patients underwent repeat studies after 1 month and 1 year. Maximum detrusor pressures during voiding and cystometric bladder capacity were compared with kidney function tests. Maximum detrusor pressures during voiding was compared with a control group and data from other studies of male infants.
At presentation median cystometric bladder capacity was 22 ml (range 5 to 125) and maximum voiding pressure was 112 cm H(2)O (40 to 331). There was no statistical difference in bladder capacity and voiding pressures before and after valve ablation. Also, patients with and without vesicoureteral reflux had similar bladder capacities and voiding pressures. There was no association between primary voiding pressures and serum creatinine levels or kidney split function during the first year of life. Primary voiding pressures were about the same as in a control group and in previous studies of males who were healthy, who had reflux or whose status was post-pyelonephritis. Voiding pressures had decreased and bladder capacity had increased significantly at 1-year followup.
Voiding pressures in infants with posterior urethral valves are as high as but not higher than other male infants. High voiding pressures postnatally are not associated with reduced kidney function.
SourceAvailable from: Geert J.M.G. van der Heijden[Show abstract] [Hide abstract]
ABSTRACT: BACKGROUND: Posterior urethral valves (PUV) may cause subtle to severe obstruction of the urethra, resulting in a broad clinical spectrum. PUV are the most common cause of chronic renal disease in boys. Our purpose was to report the incidences of kidney and bladder dysfunction in boys treated with endoscopic valve resection for PUV. METHODOLOGY: We searched MEDLINE and EMBASE databases until 1st of July 2011, to identify original papers that described outcome of endoscopic valve resection (EVR) in boys. We extracted information on (1) patient characteristics and clinical presentation of PUV related to outcomes and (2) the post-treatment absolute risks for kidney and bladder dysfunction. PRINCIPAL FINDINGS: Thirty-four studies describing renal function, vesicoureteral reflux (VUR), incontinence, and urodynamic bladder function after EVR in 1474 patients were retrieved. Patients treated for PUV show high percentages of chronic kidney disease (CKD) or end stage renal disease (ESRD), 22% (0-32%) and 11% (0-20%), respectively. Elevated nadir serum creatinine was the only independent factor associated with renal failure. Before treatment, VUR was present in 43% of boys and after EVR, VUR was present in 22%. Post treatment, 19% (0-70%) was reported to suffer from urinary incontinence. Urodynamic bladder dysfunction was seen in many patients (55%, 0-72%) after treatment of PUV. CONCLUSIONS: The reported cumulative incidence of renal and bladder dysfunction in patients with PUV after endoscopic PUV treatment varies widely. This may reflect a broad clinical spectrum, which relates to the lack of a standardised quantification of obstruction and its severity. Moreover, the risk of bias is rather high, and therefore we put little confidence in the reported estimates of effect. We found elevated nadir serum creatinine as a predictor for renal dysfunction. In order to be able to predict outcomes for patients with PUV, an objective classification of severity of obstruction is mandatory
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ABSTRACT: Bladder function is often compromised in juvenile patients with posterior urethral valves (PUV). In infancy, such abnormal bladder function is characterized by low compliance or overactivity, but later in life the bladder tends to become oversized and empties poorly. Polyuria, which is often associated with renal failure as well as secondary changes in the bladder neck, also has an effect on bladder function. Perhaps as a consequence of these contributing factors, toilet training is often delayed in children with PUV. Adults who were treated for PUV as a child tend to experience lower urinary tract symptoms at a rate twofold to threefold higher than healthy men. Furthermore, these adult patients with PUV might have risk factors for sexual and fertility dysfunctions later in life, such as cryptorchidism, renal failure and abnormal posterior urethra. However, despite the high incidence of these risk factors, sexual function and fertility seems to be normal in most patients.Nature Reviews Urology 11/2012; DOI:10.1038/nrurol.2012.196 · 4.52 Impact Factor
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ABSTRACT: This study presents a prediction model for the condensation heat transfer characteristics of binary zeotropic refrigerant mixtures inside horizontal smooth tubes. In this model, both the vapor-side and liquid-side mass transfers are considered, and the high flux mass transfer correction factor is used to evaluate mass transfer coefficients. The model was applied to the binary zeotropic refrigerant mixture R134a/R123, which has a large temperature glide. Calculation results showed that the heat transfer degradation of R134a/R123 due to gradients in the mass fraction and temperature is considerable, and depends on the mass fraction of the more volatile component and the vapor mass quality of the refrigerant mixture. By comparison with experimental data, incorporating the present finite mass transfer model for the liquid film side into the calculation algorithm was shown to reasonably well predict the condensation heat transfer coefficients of binary refrigerant mixtures with the mean deviation of about 10.3%. In the present calculations, however, it was also found that the high flux mass transfer correction factor had only a slight effect on the condensation heat transfer.International Journal of Refrigeration 08/2003; 26(5):593-600. DOI:10.1016/S0140-7007(02)00043-9 · 1.70 Impact Factor