The ornamental design for a vitalsigns monitor, as shown and described.
FIG. 1 shows a top view of the vital signs monitor that incorporates the new, original, and ornamental design;
FIG. 2 shows a bottom view the vital signs monitor that incorporates the new, original, and ornamental design;
FIG. 3 shows a side perspective view (the right and left side views are the same) of the vital signs monitor that incorporates the new, original, and ornamental design;
FIG. 4 shows a perpendicular view of the left side of the vital signs monitor that incorporates the new, original, and ornamental design;
FIG. 5 shows a perpendicular view of the right side of the vital signs monitor that incorporates the new, original, and ornamental design that incorporates the new, original, and ornamental design.