Suppression of heparinization of central venous catheters between cycles of chemotherapy

Abstract

A phase I study to evaluate heparinization of tunnelled subclavian catheters (TSC) was conducted in 42 patients who each had a TSC for chemotherapy. They were enrolled in the study from August 1994 to December 1995. The inclusion criteria were: age 18-70, no general anticoagulant treatment, TSC used only for chemotherapy, informed consent. Heparinization was performed at the end of each cycle and then at increasing intervals: 11, 13, 15, 17, 19, and 21 days. A 21-day interval was intended to mimic the suppression of heparinization between cycles. Heparinization was performed with a 250 IU/ml heparin solution. Anti-Xa activity was studied before each heparinization. For each interval, at least 5 patients were followed up for two cycles. If no blockages were present progression to the next step was authorized. If one blockage was observed 5 additional patients were required to have their TSCs heparinized after the same interval. Two blockages (block) after the same interval meant that the previous interval was recorded as the longest tolerable. There were no blocks with the 11-day interval (6 patients), 1 block after 13 days (10 patients), 1 block after 15 days (10 patients), and no blocks after 17 days (5 patients), 19 days (6 patients), or 21 days (5 patients). The median anti-Xa activity (curative rate 0.2-0.6) was, respectively 11 days 6.74; 13 days 5.47; 15 days 4.71; 17 days 3.61; 19 days 3.67; 21 days 5.10 (NS). Heparinization between two cycles of chemotherapy is unnecessary. A high level of heparin activity persisted constantly inside the catheter lumen through the 3-week observation period.

Heparin flushing and other interventions to maintain patency of central venous catheters: a systematic review

“…Rabe et al (2002) compared heparin and saline, but used them as locking solutions, instilling them only once every two days. Longterm patency with a heparin locking solution was also tested by Delva et al (1998) who left the solution in the catheter for periods ranging from 11 to 21 days.…”

9. Venous Access

“…The current attitude towards prescribing heparin, therefore, differs with regard to whether to use it at all or not, and if yes, in what way (as a flush or in PN infusion), how often and how much. In practice, wide variations are observed in volumes of provided heparin ranging from 5 to 10 ml ((93) (LOE 2+), (94) (LOE 1+), (95) (LOE 1−)), concentration of heparin ranging from 10 U/ml to 200 U/ml ((93) (LOE 2+), (94) (LOE 1+), (69) (LOE 2+)) as well as in the frequency of heparinisation that ranges from daily infusions ((96) (LOE 2++)) to flushes once or twice daily ((94) (LOE 1+); (97) (LOE 2+)) to once a week ((98) (LOE 2−)) or even once in three weeks ((99) (2++)). Boluses in children frequently contain 200 to 300 U of heparin, and for infants weighing less than 10 kg, a dose of 10 U/kg is frequently used ((89) (2++)).…”