Objective: To compare the ability of normal versus heparinized saline infusion to maintain patency of the radial artery catheter used for monitoring or multiple blood sampling.
Design: Randomized double-blind trial.
Setting: A university-affiliated hospital.
Patients: All 108 patients admitted to the surgical intensive care unit who required radial arterial line catheters. Excluded were patients who required emergency admission, those who refused to give consent, those who needed anticoagulants, thrombolytic or platelet therapy, those whose cannulation site was other than the radial artery, inadvertent discontinuation of the arterial line or incomplete data collection. This resulted in a sample of 78 adults, randomized according to date of admission.
Interventions: Forty patients admitted on odd-numbered dates received heparinized normal saline (2 units/mL), and 38 patients admitted on even dates received normal saline, both as continuous flush solutions.
Main outcome measures: Measurement of radial artery flow and pressure before and after cannulation, and catheter patency during cannulation.
Results: The type of flush solution did not adversely affect the radial artery or the hand in any measurable way. Catheter blockage occurred in three patients receiving heparinized saline and seven patients receiving normal saline as the flush solution (p = 0.06). At 96 hours of cannulation, 92% of the catheters in the heparinized saline group were patent compared with 74% in the normal saline group. Intra-arterial blood pressure was inaccurate compared with the brachial cuff pressure in 6 patients in the heparinized saline group compared with 14 patients in the normal saline group (p < 0.03).
Conclusions: There is no significant difference between flushing with normal saline and heparinized saline in the maintenance of radial arterial line patency. However, the use of a continuous heparinized flush solution in pressurized arterial lines is beneficial in that it results in greater accuracy of blood pressure monitoring than normal saline infusion.