The Effect of Skin Laxity on the PICC

Inclusion Criteria: * Patients ≥ 18 years old; * Patients who need PICC catheterization according to the doctor's advice; * There is no history of venous thrombosis, compression or blockage of superior vena cava, severe coagulation dysfunction and other contraindications for PICC catheterization; * There is no serious cardiovascular disease, such as atrial fibrillation, pulmonary heart disease and other patients with abnormal P wave, and severe heart block before catheterization * Patients who have not participated in other clinical studies; * Patients who voluntarily participate in this clinical study and can cooperate with clinical follow-up Exclusion Criteria: * Known allergy to catheter material; * The puncture site has a history of infection, injury and radiotherapy; * The puncture site has a history of venous thrombosis or surgery; * Severe abnormal bleeding and coagulation function; * Superior vena cava compression syndrome; * Surgical side limbs of breast cancer patients undergoing radical mastectomy or axillary lymph node dissection; * The ipsilateral limb of the pacemaker and the arteriovenous fistula; * patient or her/his family members refuse to sign the informed consent form.