Use of double-lumen dialysis catheters. Loading with locked heparin

Improvement in double-lumen catheter usage could provide lasting, user friendly angioaccess for patients on hemodialysis (HD), especially those on home HD. These catheters are routinely locked with concentrated heparin at the end of an HD session, in a volume corresponding to the lumen capacity. At the start of the next HD session, this heparin is aspirated with a small amount of blood and discarded. The cumulative blood loss over a long period becomes significant. The authors aimed to study whether a predetermined loading dose of heparin could be used to lock the catheter, and be administered as such during the next HD session. Thirteen patients were evaluated during four HD sessions (Rx 1 through 4; Rx 4 followed a weekend). Prior to the first study HD (Rx 1), the catheter was locked with 10,000 units heparin per lumen, as per our standard practice. Therefore, Rx 1 was considered the standard for the purpose of the study. On study HD (Rx 1 through 4), the catheter was locked with the patient's loading dose (half per lumen). The heparin loading dose was given as follows: Rx 1 and 2 = fresh heparin; Rx 3 and 4 = locked heparin. Again, activated clotting time (ACT) was measured periodically and heparin was given according to an ACT-based sliding scale. The first ACT and heparin level (drawn after the loading dose) were compared for Rx 1 vs Rx 2, 3, and 4. The mean (+/- SEM) values were as follows: Rx 1--first ACT = 299.2 +/- 16.5 sec, heparin level = 1.25 +/- 0.15 IU/ml; Rx 2--first ACT = 305 +/- 20 sec, heparin level = 1.1 +/- 0.09 IU/ml; Rx 3--first ACT = 293 +/- 18.5 sec, heparin level = 1.1 +/- 0.19 IU/ml; and Rx 4--first ACT = 288 +/- 24.1 sec, heparin level = 1.07 +/- 0.16 IU/ml. The mean of the differences between Rx 1 and Rx 2, 3, and 4, were not significantly different for all of the analyzed parameters. No catheter was lost during the study period. The results suggest that locked heparin can be effectively used as the loading dose. Advantages of this method include decreased blood wastage, heparin cost savings corresponding to the cost of concentrated heparin (approximately $156.00 per patient year for HD three time weekly), and at least one less connection per catheter lumen. The latter would possibly reduce the risk of transluminal catheter related infections.