Cartridge for a fluid management system

1. 1The ornamental design for a cartridge for a fluid management system, as shown and described.

FIG. 1 is a first front perspective view of a cartridge for a fluid management system showing our new design;
FIG. 2 is a second front perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a side view thereof;
FIG. 6 is a side view of the opposite side from that of FIG. 5;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The broken lines shown in the drawings illustrate portions of a cartridge for a fluid management system that form no part of the claimed design.