FIG. 1 is a left side elevational view of an embodiment of the medical infusion device showing my new design, the right side elevational view being a mirror image thereof;

FIG. 2 is a front side elevational view thereof;

FIG. 3 is a rear side elevational view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top front perspective view thereof;

FIG. 7 is a top rear perspective view thereof; and,

FIG. 8 is a bottom rear perspective view thereof.

The ornamental design which is claimed is shown in solid lines in the drawings. Any broken lines in the drawings are for illustrative purposes only and form no part of the claimed design.