Biplanar versus conventional two-dimensional ultrasound guidance for radial artery catheterisation

Background: Ultrasound guidance increases first-pass success rates and decreases the number of cannulation attempts and complications during radial artery catheterisation but it is debatable whether short-, long-, or oblique-axis imaging is superior for obtaining access. Three-dimensional (3D) biplanar ultrasound combines both short- and long-axis views with their respective benefits. This study aimed to determine whether biplanar imaging would improve the accuracy of radial artery catheterisation compared with conventional 2D imaging. Methods: This before-and-after trial included adult patients who required radial artery catheterisation for elective cardiothoracic surgery. The participating anaesthesiologists were experienced in 2D and biplanar ultrasound-guided vascular access. The primary endpoint was successful catheterisation in one skin break without withdrawals. Secondary endpoints were the numbers of punctures and withdrawals, scanning and procedure times, needle visibility, perceived mental effort of the operator, and posterior wall puncture or other mechanical complications. Results: From November 2021 until April 2022, 158 patients were included and analysed (2D=75, biplanar=83), with two failures to catheterise in each group. First-pass success without needle redirections was 58.7% in the 2D group and 60.2% in the biplanar group (difference=1.6%; 95% confidence interval [CI], –14.0%–17.1%; P=0.84), and first-pass success within one skin break was 77.3% in the 2D group vs 81.9% in the biplanar group (difference=4.6%; 95% CI, 8.1%–17.3%; P=0.473). None of the secondary endpoints differed significantly. Conclusions: Biplanar ultrasound guidance did not improve success rates nor other performance measures of radial artery catheterisation. The additional visual information acquired with biplanar imaging did not offer any benefit. Clinical trial registration: N9687 (Dutch Trial Register).