Keeping central venous lines open: a prospective comparison of heparin, vitamin C and sodium chloride sealing solutions in medical patients.

Objective: To prevent catheter occlusion, intermittently used central venous catheters are frequently sealed with vitamin C solution or heparin solution between use. The present study was designed to test the effectiveness of this approach and to compare the efficiency of sealing solutions.
Design and Setting: Prospective randomized study performed on a 9-bed medical ICU and on medical wards of an academic tertiary care center. PARTICIPANTS. Ninety-nine central venous line placements were prospectively included in the study and randomized into three treatment groups: sodium chloride 0.9%, vitamin C (200 mg/ml) and heparin (5000 IU/ml) sealing solutions.
Interventions and Measurements: Catheters were filled with the respective sealing solution and patency was tested once every 2 days using a standardized routine. Catheter patency was compared among the three groups using Kaplan-Meier statistics and log-rank testing.
Results: There was a significant difference in catheter patency between the three groups (p<0.03, log-rank test). A comparison of catheter survival between the catheters filled with heparin and those filled with sodium chloride, but not between those filled with vitamin C solution and with sodium chloride solution, exhibited significant differences in catheter patency (p<0.04, log-rank test).
Conclusions: Local anticoagulation of intermittently used central venous catheters prolongs catheter patency. High-dose (5000 IU/ml) heparin solution is a useful anticoagulant for this purpose, while vitamin C solution does not prolong catheter patency.