Ultrasound guidance versus direct palpation for radial artery catheterization by expert operators: a randomized trial among Canadian cardiac anesthesiologists.

PURPOSE: The use of ultrasound (US) for radial arterial catheterization has been reported to result in faster insertion times with fewer complications when compared with traditional direct palpation (DP). We sought to determine if this applies to expert operators and tested the hypothesis that, among cardiac anesthesiologists, US-guided insertion similarly results in faster insertion times as well as fewer re-directs, attempts, and complications.

METHODS: Following Research Ethics Board Approval, we conducted a randomized clinical trial in 125 patients scheduled for cardiac surgery at a single tertiary/quaternary care centre. Patients were randomized to either US- or DP-guided radial artery catheterization by attending cardiac anesthesiologists. The primary endpoint was time to catheter placement. Secondary endpoints included the number of attempts and re-directs as well as the failure rate.

RESULTS: There were no differences between the DP- (n = 62) vs US-guided (n = 63) groups in median [interquartile range] time to placement (104 [76-212] sec vs 104 [68-270] sec, respectively; P = 0.66), number of re-directs (2 [0-6] vs 3 [1-5], respectively; P = 0.82), or number of attempts (1 [1-2] vs 1 [1-2], respectively; P = 0.08). The first-attempt success rate was 56.4% in the DP group and 71.4 % in the US group (P = 0.10). Failure rate and hematoma rate in the DP group were 21.0% and 22.6%, respectively, compared with 12.7% and 11.1% in the US group (P = 0.24 and 0.10, respectively).

CONCLUSIONS: Among experienced cardiac anesthesiologists, the use of US to facilitate radial arterial catheterization did not affect insertion times, the number of re-directs, or the number of attempts when compared with DP. Ultrasound use had no significant effects on the rates of success on first attempt, failure, or hematoma formation. This trial was registered at www.clinicaltrials.gov : NCT02118441.