Application of Intracavity Electrocardiogram Positioning Technique in PICC

Inclusion Criteria: * Patients ≥18 years old who need PICC catheterization for the first time according to the doctor's advice; * No serious cardiovascular diseases before catheterization, such as atrial fibrillation, pulmonary heart disease and other P wave abnormalities, serious heart block, etc.; * patients who did not participate in other clinical studies; * Patients who voluntarily participated in the clinical study, signed informed consent and cooperated with clinical follow-up Exclusion Criteria: * patients with local malformation or scar formation; * Patients with infection or damage at the puncture site; * patients with tumor compression of blood vessels; * Patients with confirmed or suspected catheter-related infection, bacteremia and septicemia * Patients diagnosed or suspected to be allergic to silicone material * Patients with a history of radiotherapy at the pre-intubation site * Patients with a history of venous thrombosis, trauma or vascular surgery * Patients with superior vena cava syndrome * Patients with poor medical behavior * Patients with severe peripheral vascular edema * High-flow fluid infusion, patients requiring hemodialysis, pacemaker installation, crutches, or patients who may undergo A-V fistula