The fluid dynamics of the lower urinary tract

Millar, W. T (1972) The fluid dynamics of the lower urinary tract. PhD thesis, University of Glasgow.

Abstract

Chapter 1 contains a general review of the physiology and fluid dynamics of the lower urinary tract. A radioisotope technique for the measurement of urine flowrate simultaneously with bladder pressure has been developed and is discussed in Chapter 2. The method also permits the measurement of residual urine. The techniques used for the measurement of bladder pressure and abdominal pressure are also discussed. The rigid tube model of the urethra is presented in Chapter 3. The measurements obtained from a group of female patients suffering from stress incontinence are presented in Chapter 4. No direct correlation between the peak urine flowrate, and the bladder pressure at peak flowrate, initial volume in bladder, volume voided and the micturition time was obtained. Multiple linear correlation, however, revealed an interdependence between all of the variables. Using data measured by xroigaard (1970) in a group of young children, for which. no direct correlation was found, it was found that there was again an interdependence. The analyses, however, suggested that the two groups of patients were different. This method of analysis may, therefore, help in the classification of incontinont patients. The comparison of parameters determined using the rigid tube model and the clinically obtained values showed that the rigid tube model correlated well with the observations. However, the high degree of correlation between the resistance index (bladder pressure/ flowrate2 ) directly obtained from clinical measurements and the resistance defined by the rigid tube model show that the model is an unnecessary complication. The theory of flow in elastic tubes is discussed in Chapter 5. It is shown that the tissue defines a critical flowrate which deter- mines the general shape of the urethral profile during micturition. The occurrence of supercritical flow (that is, the urine flowrate is greater than the critical flowrate) may explain certain urethral profiles observed during micturition cystography, and the associated high resistances. The high transient flowrates with subsequently reduced flowrate may also be explained using the concept of supercritical flow. This is discussed in Chapter 6. It is also shown in Chapter 6 that the critical flowrate in excised dog urethras is of the order of 10 ml/sec upwards and that the occurrence of supercritical flow in the human subject is probable in certain cases.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: S Alexander
• Keywords: Physiology, Fluid mechanics
• Date of Award: 1972
• Depositing User: Enlighten Team
• Unique ID: glathesis:1972-72887
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 11 Jun 2019 11:06
• Last Modified: 11 Jun 2019 11:06
• URI: https://theses.gla.ac.uk/id/eprint/72887