Long-versus Short-Axis Ultrasound Guidance for Subclavian Vein Cannulation

With the long-axis approach the vein appeared in the longitudinal view. With this approach only the vein was visible on the screen. The needle was held at a 30° angle, oriented in-plane with the transducer and the skin punctured at the base of the transducer. The vessel alignment was maintained during the procedure and the entire length of the needle was visible during the progression through the tissues.

With the short-axis approach the probe was positioned almost perpendicularly to the clavicle. The needle was held at an angle of 45° relative to the skin surface and sagittal to the plane of the probe (out-of-plane). During the progression to the vessel, the visualization of the needle was limited to the deformation of tissue and artefacts produced by needle advancement. When the tip abutted the vein wall, additional pressure produced transient vessel deformation, which disappeared once the wall was penetrated.