Inaccurate blood flow rate during rapid hemodialysis.

Simulated hemodialysis with isotonic saline was performed to compare the requested blood flow rate (BFR-r) with the actual blood flow rate (BFR-a) delivered during rapid, efficient hemodialysis. Four different blood pumps and blood lines from three different manufacturers were used for the studies. BFR-r was set on each blood pump, and a timed outflow specimen from the dialysis circuit was used to measure the BFR-a delivered. BFR-r values of 200, 350, and 500 mL/min were used; the arterial pressure was set at -50, -250, and -325 mm Hg. BFR was determined every hour for 5 hours. At an arterial pressure of -50 mm Hg, the BFR-a was slightly higher than the BFR-r, and this did not vary over the 5-hour study period. When the arterial pressure was -250 mm Hg, the initial BFR-a was 95% of the BFR-r; at the end of the 5-hour study, this had declined to an average of 87% of the BFR-r. The largest discrepancy between BFR-a and BFR-r was at an arterial pressure of -325 mm Hg; the initial actual values averaged only 90% of the requested, and by the end of the 5-hour study, this value had declined to a mean of 78% of the BFR-r. The use of whole blood with a hematocrit value of 33% and the addition of venous resistance did not significantly affect these results.(ABSTRACT TRUNCATED AT 250 WORDS)

Deferoxamine and coated charcoal hemoperfusion to remove aluminum in dialysis patients.

We studied the in vitro and in vivo characteristics of aluminum (Al) removal by coated charcoal hemoperfusion (HP) in combination with intravenous deferoxamine (DFO). DFO enhanced the clearance of Al by HP in vitro after 180 minutes of perfusion with a solution containing 403.3 +/- 14.0 ng/ml of Al at 150 ml/min. The Al clearance was 139 +/- 1.0 ml/min with DFO and 49 +/- 10.0 ml/min (P less than 0.001) without DFO. Addition of DFO enhanced in vitro Al removal from 5.5 +/- 0.9 mg to 10.0 +/- 1.2 mg (P less than 0.05). During our in vivo studies, an HP device was in series in the dialysis circuit after a Cuprophan hemodialyzer. Eight patients with Al toxicity were studied on twelve occasions. Patients received DFO (40 mg/kg) 40 hours before the study. The total Al clearance with the combined hemodialysis (HD) and HP devices was higher than that obtained by the dialyzer alone at 30 minutes (62 +/- 4.9 ml/min vs. 25 +/- 2.5 ml/min, P less than 0.02) and after 180 to 210 minutes (32 +/- 3.0 ml/min vs. 19 +/- 2.9 ml/min, P less than 0.02). After 120 minutes the Al clearance by the HP device alone was significantly lower than the initial Al clearance by HP. Combined HD plus HP removed 2.9 +/- 0.4 mg of Al, whereas the total removal of Al by HD alone was 1.5 +/- 0.3 mg (P less than 0.01).

Acute renal failure treated by slow continuous ultrafiltration. Preliminary report.

We report our initial experience with the use of slow continuous ultrafiltration in the treatment of acute renal failure. Advantages of slow continuous ultrafiltration over conventional hemodialysis are greater blood pressure stability, no need for systemic anticoagulation, augmented fluid input and removal, and enhanced ease of operation. Our results in two patients confirm other reports that this method can be successfully performed in hemodynamically unstable patients with acute renal failure.