Heparin or saline for arterial line patency?
This Cochrnae review (Robinson-Malt et al, 2014) found insufficient evidence to support the use of heparin for patency of arterial lines. The available evidence is of poor quality because of risk of bias and does not provide sufficient information to support the effects of adding heparin (1 to 2 IU/mL) to a maintenance solution (pressurized to deliver 3 mL of flush solution per hour) of 0.9% normal saline in maintaining the patency and functionality of arterial catheters.
Robertson-Malt S, Malt GN, Farquhar V, Greer W. Heparin versus normal saline for patency of arterial lines. Cochrane Database of Systematic Reviews, No. 5, 2014. DOI: 10.1002/14651858.CD007364.pub2.