“…In many cases, such as obesity, thoracic deformity, and emergency status, the landmark method is a challenge and has a high incidence of complications (1,2). In the central line placement with the application of ultrasound, the puncture under direct vision, can significantly reduce complications, including pneumothorax, arterial injury and nerve damage, significantly improve patient safety (3)(4)(5). In previous studies, ultrasound method had a superior advantage in the jugular vein and femoral vein cannula compared to the landmark method (6,7).…”