Abstract
Some methods such as ultrafiltration or hemofiltration have been known to show a minimal disturbance of the circulatory function in spite of the rapid removal of large amount of body fluid. The reports that the decrease of circulating plasma volume (CPV) and the dialysis-induced hypotension were prevented by priming with dextran, mannitol strongly suggest the importance of plasma osmolality on the stability of cardiovascular system. This paper is concerned with fluid exchange to see which factors affect the circulatory stability during hemodialysis.
It was shown that not only the removal rate of fluid but also the fall of plasma osmolality during the passage of blood through the dialyzer can affect the CPV and the blood pressure level. The fall of osmolality is caused mainly due to the removal of urea, and suggested to interfere with the efficient fluid shift from intracellular to extracellular space and the capillary refilling rate, resulting a hypovolernia. This osmolality fall seems, therefore, the one reason of the difference found in the circulatory complications in several methods of hemodialysis. A correction of urea-dependent osmolality or high sodium dialyzate will promote the efficiency of fluid removal from the intracellular fluid space with a concomitant circulatory stability.
