Ultrasound evidence of the optimal wrist position for radial artery cannulation

Radial artery cannulation is a common medical procedure for anesthesia and critical care. To establish the ideal wrist position for radial artery cannulation, we performed ultrasound examinations of the radial artery to investigate the effect of the angle of wrist extension on radial artery dimensions.

Measurements were performed in 17 healthy subjects and 17 surgical patients scheduled for coronary artery bypass graft (CABG) surgery. The radial artery was echographically visualized near the styloid process of the radius at the wrist. Radial artery dimensions were measured at wrist joint angles of 0, 15, 30, 45, 60 and 75 degrees .

In both groups, radial artery height was affected by the wrist joint angle. Vessel height was decreased at 60 degrees (one way ANOVA P = 0.027 vs 0 degrees ) and 75 degrees (P < 0.001 vs 0, 15, 45 degrees ) in healthy subject and at 75 degrees in CABG patients (P < 0.001 vs 0 degrees ). The mean differences in radial artery height at 0 and 75 degrees were 0.33 +/- 0.09 mm and 0.20 +/- 0.06 mm for healthy and CABG patients, respectively. Vessel width was not affected by wrist joint angulation up to 75 degrees of extension.

Our results demonstrate that in healthy subjects, radial artery dimensions are unaltered when the wrist joint is extended up to an angle of 45 degrees . Extension at 60 degrees for healthy subjects and 75 degrees for CABG patients, however, results in a decrease in the height of the radial artery, which could possibly render arterial catheterization more difficult.