Abstract
Background
Cleaning the urinary tract by so-called “wash-out effect” and promoting high diuresis has long been advocated but has had very little scientific backing and few prospective studies in international journals.
Aim
To verify whether the physical laws describing the transport force of water in rivers and pipes are also valid for urinary outflow.
Methods
A laboratory model for measuring transport force, given liquid and solid capacity, was adapted to create an in vivo model based on the rabbit urinary tract.
Results
Fluid flow in the rabbit renal pelvis and ureters was found similar to flow in pipes, obeying the physical laws of water transport to some extent. When the quantity of liquid flowing in the urinary tract in unit time was doubled, the transport force increased by various orders of magnitude. When the liquid increased by a larger factor, the transport force became enormous.
Conclusions
The results confirm the utility of maintaining high diuresis in patients with renal calculus, but stress the utility of drinking 1–2 liters of hypotonic water in a short time to obtain an enormous increase in transport force which increases the probability of a cleansing effect.
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