How does rHuEPO effect D/P creatinine ratios?

Initially starting CAPD patients on EPO was concerning after hearing reports of hemodialysis patients stating that they "may need more dialysis". The rationale given was that with a higher hematocrit the percentage of plasma in whole blood would decrease, leading to an increase of red cell mass. This decreased plasma volume and increased viscosity would lead to a slower blood flow ultimately resulting in less efficient dialysis. Assessing CAPD patients' peritoneal efficiency was the next step. We obtained pre and post-EPO PETs and evaluated. The initial results showed that D/P creatinine ratios were dropping as our Hcts increased, and ultrafiltration results projected an improvement. What remained unanswered was what took place over extended periods of time on EPO therapy. We examined twelve patients over a period of 27 months. Each patient received 4 exchanges per day using 1500 to 2500 volume. PET tests were performed on each patient prestudy, and at months three, six, and 25-27. Initially each patient received EPO 4000 units, 3/week, SQ. EPO easily increased and maintained our patients' hematocrits within 12 weeks after starting the study. D/P creatinine ratios initially dropped but as our study continued there was a return of D/P creatinine ratios to 6% greater than baseline. One report suggests that EPO may have a direct vasoconstricting effects on blood vessels caused by the stimulation of calcium toward the cell. Vasoconstriction of the vessels would lead to a decrease in exchangeable surface area resulting in a decreased D/P creatinine ratio.(ABSTRACT TRUNCATED AT 250 WORDS)