The ornamental design for a patientmonitor, as shown and described.
FIG. 1 is a perspective view of a patient monitor showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a right side view thereof; and,
FIG. 7 is a left side view thereof.
The dash-dash broken lines depict portions of the patient monitor that form no part of the claim design. The dotted broken lines illustrate boundaries between claimed and unclaimed surfaces and form no part of the claimed design.