How To Catch Urea? Considerations on Urea Removal from Hemofiltrate

Publisher Website
Google Scholar
Abstract
Hemofiltration imitates the 1st step in the natural function of the [human] kidney. After separation from corpuscular and high MW blood components, a filtrate remains which contains urea together with electrolytes and other low MW metabolites. To use a hemofilter in a recirculating closed-loop system, a big quantity of urea must be eliminated. Attempts to solve this problem are presented. Reasons are given for the difficulty to eliminate urea directly from dilute aqueous solutions. Explanations for ambiguous results of some reactions proposed for urea removal are discussed. The concept of hard and soft acids and bases is used to develop demands to the structure of a reagent which reacts preferentially with urea in aqueous solution. On monomeric model substances (activated aldehydes) this hypothesis is proven in vitro. In spite of the given technical possibility of urea removal, solving the problem of urea removal may not enable a closed-loop system for alternative simpler or more economic ways of treating renal failure.