| 1. |
- Ask, Per, et al.
(författare)
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A SHORT-TIME-DELAY URINARY FLOWMETER
- 1985
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Ingår i: Neurourology and Urodynamics. - : Wiley. - 0733-2467 .- 1520-6777. ; 4:3, s. 247-256
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Tidskriftsartikel (refereegranskat)abstract
- A urinary flowmeter has been designed, using a quickly rotating disc and a balance principle. The flowmeter has a fast and accurate response to changing flows. The time delay of the flowmeter is less than about 0.25 s. The improved accuracy in recording urinary flow using the presented flowmeter should make it possible to extract more information from the detrusor pressure and urinary flow relations, relevant for assessing lower urinary tract function.
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| 2. |
- Spånberg, Anders, et al.
(författare)
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PRESSURE-FLOW STUDIES IN ELDERLY MEN WITHOUT VOIDING PROBLEMS - ESTIMATION OF THE URETHRAL PRESSURE-FLOW RELATION AND URETHRAL ELASTICITY
- 1990
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Ingår i: Neurourology and Urodynamics. - : Wiley. - 0733-2467 .- 1520-6777. ; 9:2, s. 123-138
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Tidskriftsartikel (refereegranskat)abstract
- The flow in the urethra is controlled by an elastic constriction, the flow-controlling zone. The distensibility of this zone is described by the pressure/area relation, which gives the static pressure as a function of the cross-sectional area at the flow-controlling zone. The pressure/area relation can be calculated from the pressure/flow relation, which is estimated from the pressure/flow plot obtained at a urodynamic examination. In this study the urethral pressure/flow and pressure/area relations were estimated for 21 randomly selected men (62–75 years old) without voiding problems.Nineteen of 21 persons in this group had pressure/flow relations with a low slope. This corresponds to a low slope in the pressure/area relation indicating high distensibility of the flow-controlling zone, which for 18 persons was estimated to be distended to areas larger than 10 mm2 during micturition. Twenty persons had a minimal urethral opening pressure below 55 cm H2O. The estimated pressure/area relation was linear in 59% of the micturitions, indicating that the flow-controlling zone could have been distended to a larger cross-sectional area, if the bladder had achieved a higher pressure. The 10th–90th percentiles for maximum flow and detrusor pressure at maximum flow were 7.2–24.3 ml/s and 24–76 cm H2O, respectively. Four persons had low flow and low pressure, indicating diminished detrusor contractility with age. Twenty-four percent of the persons had unstable bladder contractions with a pressure rise < 15cm H2O and 19% with a pressure rise < 15cm H2O.
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| 3. |
- Spånberg, Anders, et al.
(författare)
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QUANTIFICATION OF URETHRAL FUNCTION BASED ON GRIFFITHS MODEL OF FLOW THROUGH ELASTIC TUBES
- 1989
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Ingår i: Neurourology and Urodynamics. - : Wiley. - 0733-2467 .- 1520-6777. ; 8:1, s. 29-52
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Tidskriftsartikel (refereegranskat)abstract
- Griffiths' model of flow-through elastic tubes makes it possible to relate the elastic properties of the flow-controlling zone to the pressure/flow relation of the urethra. In this work the pressure function p(A) = Pmo + Kn An, where A is cross-sectional area, Pmo the minimal opening pressure, and Kn and n parameters describing urethral distensibility, describes the elastic properties of the flow-controlling zone. By curve-fitting in the pressure/flow plot, the three parameters pmo, Kn, and n can be estimated analytically. Using this model it is possible to identify three different biomechanical changes that may cause obstruction. First, pmo may be elevated. Second, the urethra can be distended to a certain area only, corresponding to high values of Kn and n. Third, the urethra can be distended but a higher-than-normal pressure increase above Pmo is needed, Kn is high, and n is low. With this model it is possible to quantify urethral function for both scientific and clinical purposes.
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