Patency of radial arterial catheters

Data on the influence of flush methods, blood-sampling methods, and site location on the patency of radial arterial catheters used for pressure monitoring are sparse.

To determine the effects of flush and blood-sampling methods, insertion site, and sex of patients on catheter patency.

In a randomized trial, 174 patients requiring radial arterial pressure monitoring were assigned to 4 groups: fast flush as needed and nonwaste blood sampling; fast flush as needed and waste blood sampling; fast flush every 4 hours and waste blood sampling; and fast flush every 4 hours and nonwaste blood sampling. All site locations were evaluated for patency, and all monitoring systems were maintained with isotonic sodium chloride solution.

Nonpatent catheters were 4.23 times more likely in patients with insertion sites 3 cm or higher above the bend of the wrist than in patients with lower sites (P = .01). Duration of patency did not differ between catheters maintained with fast flush every 4 hours and those flushed as needed or between catheters according to the method of blood sampling. Women were 3.05 times more likely than men to have nonpatent catheters (P = .02). With insertion sites 3 cm or higher above the radiocarpal joint, nonpatency was 7.3 times more likely in women than in men (P < .001).

Insertion sites closest to the bend of the wrist increase chances of maintaining patency. Catheters can be maintained with as-needed flushes, and either waste or nonwaste blood sampling can be used.