Sonographic visualization and cannulation of the axillary vein in two arm positions during mechanical ventilation: A randomized trial.

Background: Abduction of the arm has been used for ultrasound-guided infraclavicular axillary vein cannulation. We evaluated the influence of arm position on sonographic visualization and cannulation of the axillary vein in patients receiving mechanical ventilation.

Methods: Sixty patients scheduled to undergo surgery under general anaesthesia with controlled mechanical ventilation were included in this prospective randomized study. The depth, size and distance of axillary vein to the pleura were recorded at three points: Point A, the most proximal part of the axillary vein visualized with adduction; Point A', Point A in abduction; and Point B, the most proximal part of axillary vein visualized in abduction. Cephalic movement of the clavicle at Point A' and the distance between Point A and Point B were noted. In Group A, cannulation was performed at Point A in the adducted arm and at Point B with the abducted arm in Group B after randomization.

Results: Abduction moved the clavicle cephalad by 2.2 ± 0.6 cm and increased sonographic visualization of the axillary vein by 2.2 ± 0.5 cm in length, when compared with adduction. The distance from the vein to pleura was higher in Point A' (p < 0.001). No differences were found during cannulation in terms of first-pass success rate or number of attempts.

Conclusion: Abducted position moved the clavicle cephalad and allowed sonographic visualization of infraclavicular axillary vein approximately 2 cm more proximally than with the adducted arm, with a comparable rate of cannulation success.