BACKGROUND: Currently, short-axis out-of-plane (SA-OOP) and long-axis in-plane (LA-IP) ultrasound techniques are used to guide radial artery cannulation. In this study, we compared the success rate of a modified SA-OOP technique with that of traditional LA-IP.
METHODS: One hundred sixty-four patients who were to undergo liver surgery or splenic resection under general anesthesia were included. Using a sealed envelope method, patients were randomly divided into 2 groups: the modified SA-OOP or the LA-IP ultrasound guidance approaches. The number of cannula insertion attempts until success was recorded in both groups. The primary end point to compare the groups was the rate of cannula insertion successes on the first attempt. The secondary end points were also recorded and compared: insertion failure rate, inner diameter of the radial artery, depth of artery from the skin, ultrasonic location time, cannulation time, and vascular complications including thrombosis, hematoma, edema, and vasospasm.
RESULTS: The cannula insertion success rate on the first attempt was significantly higher in the modified SA-OOP group compared with the LA-IP group (proportion difference 15.7%, 95% confidence interval [CI], 0.6%–30.7%, P = 0.0158). However, the insertion failure rate was not different between groups (95% CI, −17.7% to 12.8%, P = 0.4969). The ultrasonic location time was significantly decreased in the modified SA-OOP group compared with the LA-IP group (mean difference −9.5 seconds, 95% CI, −10.6 to −8.5 seconds, P < 0.0001). However, there was no significant difference between groups for cannulation time (95% CI, −0.6 to 7.6 seconds, P = 0.1152), depth of artery (95% CI, −0.07 to 0.57 mm, P = 0.1050), and the diameter of the radial artery (95% CI, −0.30 to 0.03 mm, P = 0.1153).
CONCLUSION: The modified SA-OOP technique may improve the success rate of cannula insertion into the radial artery on the first attempt.