Abstract
The urea rebound phenomenon, a rapid increase in plasma urea concentration after HD therapy, is quite familiar. The urea rebound rate was calculated by measuring the post-hemodialysis plasma urea concentration after 92 hemodialyses in 23 patients. The course of the urea rebound phenomenon, its causes and its influence on Kt/V, TACurea and pcr calculations were investigated.
Urea rebound was observed after routine hemodialysis (4 hrs at 200ml/min blood flow). The urea rebound rate was 16%, and the plasma urea concentration became equilibrated within 30min after dialysis. Rebound was caused by entry of urea from a poorly cleared second pool and was not due to an actual increase in the rate of urea generation.
A significant correlation was found between the urea rebound rate and Kt/V. The different values of Kt/V, TACurea and pcr were calculated using the plasma urea concentration at the end of hemodialysis and 30min after dialysis, and compared. The former Kt/V (0.15, 15.6%) and pcr (0.08g/kg/day, 8.5%) values were higher and the TACurea (2.0mg/dl, 4.0%) value was lower than the latter.
Thus, if the urea rebound rate, is not taken into account the Kt/V, TACurea and pcr values calculated using the plasma urea concentrations immediately after hemodialysis could be higher or lower than expected and therefore misjudged in terms of their clinical evaluation.
