Venous access management plays a key role in patient care and preserving their venous capital. The so-called "conventional" peripheral venous catheter is the most common venous access device, but it is associated with a high rate of complications, particularly in cases of prolonged use or poor venous capital. Recommendations, such as those from MAGIC or SF2H, advocate their use when the intended duration of use is 5 days or less. For longer periods or in cases of difficult access, so-called "central" devices such as PICC lines or central venous catheters are used, although they present specific risks such as CLASBI or deep vein thrombosis.

In intermediate situations, the midline, a peripheral venous access device, is a relevant alternative, particularly for non-venotoxic intravenous treatments lasting more than 5 days. Although it is theoretically associated with fewer infections and complications than the PICCline, its complication rate and actual duration of use vary widely in the literature.

The MAGIC recommendations suggest using them for periods of 14 days or less. The widespread use of midlines in healthcare facilities, and in particular the creation of vascular access units, has given rise to issues shared between centers, notably the replacement rate of these devices. The study therefore aims to determine the replacement and early removal rates for midlines, the circumstances in which they are replaced, and toassess the relevance of the 28-day limit in the choice of device, in order to improve practices and optimize the practitioner's initial decision.

Inclusion Criteria:

• Patients over 18 years of age.
• Patients who have given their consent to participate in the study.
• Patients treated in a hospital unit authorized to insert midlines, or who have a midline inserted by a professional trained in this procedure, in accordance with the local organization of each center.
• First insertion for the treatment of a given event with an expected treatment duration of 28 days or less.
• Patients treated with a midline catheter at least 14 cm in length.

Exclusion Criteria:

• No coverage by the social security system
• Failure to insert the midline
• Patient under guardianship or conservatorship

Patients included in the study are those whose midline indication has been validated by the vascular access unit according to the hospital's organization. The expected duration of midline use should be 28 days or less.