(A)typical symptoms during single needle dialysis. In 5 elderly patients, an abnormally high occurrence of some symptoms was noted during dialysis. All patients were dialyzed with biocompatible membranes, bicarbonate dialysate, and a blood flow of 250 to 300 ml/min by a single needle system, on a fistula 14 Gauge catheter-needle. These symptoms were: 1) "angina," resistant to O2 and nitrates, with biochemical stigmata of infarction, but without electrocardiogram (ECG) localization; 2) intractable persistent hypotension, not hypovolemic, lasting 1 or 2 days; 3) esophagal spasms, with inability to swallow solid food. Because we knew that these symptoms were compatible with hemolysis (biochemically proven by the increase in serum LDH during dialysis and by a fall in haptoglobin) due to red cell fragmentation (RCF), we switched these patients from fistula dialysis (A) to central catheter dialysis (B), with the same apperture, blood flow, etc. The total number of sessions of A versus B were 512 and 891; the mean LDH ratios (serum LDH postdialysis divided by predialysis) were 1.8 and 1.0 (= no RCF); angina events were 132 (26%) for A, and 25 (3%) for B; persistent hypotension was seen 37 (7%) times in A and 5 (0.6%) times in B; esophagal spasms were noted 65 (13%) times for A, and 0 times for B. This clinical improvement was so overwhelming that 3 patients refused to be dialyzed again using their well functioning fistulae. This study also proved the need for a better designed and manufactured peripheral dialysis catheter-needle. 