HEMOLYSIS AND RECIRCULATION IN SINGLE NEEDLE DIALYSIS

We performed standard two-needle dialysis (TND) in 16 patients through double lumen subclavian catheters and single-needle dialysis (SND) in 16 patients through single-lumen catheter, all of whom had end stage renal failure, and compared these two groups with respect to hemolysis and recirculation (R). Blood urea nitrogen (BUN), lactic dehydrogenase (LDH), potassium, hemoglobin (Hb) and plasma free Hb levels were determined before and after hemodialysis (HD). Plasma free Hb levels were measured spectrophotometrically. R % values were calculated from the BUN values in blood samples obtained from peripheral vein, arterial and venous lines simultaneously in the last five minutes ofHD. There were no differences between the two groups in respect to predialysis plasma free Hb, LDH and potassium values. The percentage of R, post dialysis plasma free Hb, LDH and potassium values in the SND group were significantly higher than those of the TND group; however, the percentage of reduction in BUN was found to be lower in the SND group. A positive significant correlation was present between mean R % values and post dialysis plasma free Hb levels (r= 0.68, p< 0.0001). We conclude that the high recirculation rates in SND led to intravascular hemolysis as well as decrease in HD efficiency. Hemolysis did not change total Hb level. No significant difference in post dialysis serum potassium level was detected in the SND group because of potassium release resulting from hemolysis and thus SND is not suitable in hyperpotassemic and hypercatabolic patients.