Midline catheters (according to European and Australian terminology) are peripheral venous access devices, inserted into the deep veins of the arm by ultrasound guidance, 15-25 cm long, whose tip is placed in the subclavian or axillary vein (hence also the name 'midclavicular'). Fallen into disuse in the USA, they are widely used in Europe (Italy, Spain and UK), especially in palliative care.
The duration of the midline is substantially linked to the appropriateness of use (or to the use exclusively for the infusion of solutions compatible with the peripheral route).
We recommend to use polyurethane midline, open-ended, non-valved, preferably power injectable. Silicon midlines are fragile, have low flow, and are difficult to disobstruct: they should be abandoned. There are no advantages in using valved midlines - in fact there are specific disadvantages (such as the increased incidence of malfunctions and the higher cost).
The use of midlines is not widespread in the pediatric field and is usually reserved for older children in adolescence, where the calibers and lengths provided for in the adult can be used.