Effects of heparin versus saline solution on intermittent infusion device irrigation. The purpose of this study was to compare the effectiveness of 1 ml of 0.9% sodium chloride with 10 units of heparin in 1 ml sodium chloride solution, both containing benzyl alcohol, in maintaining patency and reducing the incidence of phlebitis in patients with intermittent infusion devices. The subjects (N = 32) were randomly assigned in a double-blind experimental design. Repeated-measures analysis of variance revealed no significant difference between the groups in phlebitis or patency variables. The results from this controlled study would suggest that 0.9% sodium chloride is as effective as 10 units of heparin in sodium chloride solution in maintaining intermittent infusion device patency and preventing phlebitis. 