Patients with bad elbow vascular conditions can choose Peripherally Ingerted Central Catheter(PICC), we generally adopt the supine position, but for some patients forced semi-sitting,it's better to use BD20G ordinary straight catheter instead of BDMST safety indwelling, and use negative suction pressure to determine the accuracy of the needle into the vein,before punctureing,we should shiatsu posterior border of supraclavicular sternocleidomastoid,and ask the patient to cough to make the external jugular vein unfilling,when we do catheter maintenance,we can modify the sterile foil slightly for constructed tightly and conveniently.