Impact of Heparin Hemodialysis Catheter Lock on Partial Thromboplastin Time Assays in Inpatients on Therapeutic Intravenous Heparin.

Objective: Multiple in vitro and in vivo studies indicate that there is a significant amount of dialysis catheter lock leak with tunneled and nontunneled dual lumen hemodialysis (HD) catheters. The impact of heparin 1000 unit/mL HD catheter lock on outcomes in patients on therapeutic heparin has not been previously reported.

Methods: Twenty-nine patients with 42 patient events on HD or continuous renal replacement therapy (CRRT) via double lumen catheters were retrospectively analyzed. Study patients received heparin 1000 unit/mL HD catheter lock while on therapeutic intravenous heparin. All patients had stable activated partial thromboplastin times (PTT) prior to catheter locking and had a PTT drawn within 6 h after administration of the heparin HD catheter lock.

Results: The average prelock PTT was 56 s and postlock PTTs increased on average to 85 s (p < 0.0001). PTTs were significantly higher when drawn closer to the administration time of the heparin catheter lock. Major bleeding occurred in many surgical patients after heparin HD catheter lock administration.

Conclusion: Citrate or saline HD catheter lock may be preferable to heparin HD catheter lock in patients on intravenous heparin infusions, especially in high-bleed-risk surgical patients.