A clinical audit of the impact of heparin locking solution concentration on catheter dysfunction

Aim:

To determine if a change to low dose (1000 units/mL) from high dose (5000 units/mL) heparin lock concentrations has resulted in increased haemodialysis catheter dysfunction.

Background:

Haemodialysis catheters are locked with solutions such as heparin to prevent dysfunction from thrombus formation, a major contributor to catheter associated morbidity and mortality. Our centre changed to low dose from high dose heparin concentration locks in June 2018, in line with guideline recommendations.

Method:

Retrospective analysis of all patient records who had insertion of a permcath between January 2016 to April 2020 at The Royal Hobart Hospital. Alteplase use was regarded as a surrogate for catheter dysfunction.

Results:

We identified a total of 118 permcaths representing 19,251 catheter days in 101 patients (60 women (51%), mean age 62 (range 19-85). There were 35 patients in the low dose group (group 1) vs. 66 in the high dose group (group 2). There were 8,047 vs. 11,204 catheter days and 50 vs. 53 total number of alteplase doses in the two groups respectively. Days to first alteplase use was 85 in group 1 vs. 130 in group 2 (p = 0.70). Total rate of alteplase use per 100 catheter days was 0.62 in group 1 vs. 0.47 in group 2 with a rate ratio of 1.32 (p = 0.17, 95%CI 0.87 to 1.97). Catheter bleeding rates were also not different with a rate ratio of 0.70 (p = 0.51, 95%CI 0.19 to 2.24).

Conclusions:

Change to low dose from high dose concentration heparin locks has not resulted in increased catheter dysfunction and interestingly this change has not been associated with a reduction in bleeding rates.