We claim the ornamental design for a breathing monitoring device, as shown and described.
FIG. 1 is a front perspective view of a breathing monitoring device showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left-side view thereof;
FIG. 5 is a right-side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a bottom perspective view thereof;
FIG. 9 is an enlarged view of the encircled portion in FIG. 1;
FIG. 10 is an enlarged view of the encircled portion in FIG. 4;
FIG. 11 is an enlarged view of the encircled portion in FIG. 5; and,
FIG. 12 is another bottom perspective view showing an example state of use of the breathing monitoring device shown in FIG. 8 from which a saw-tooth shaped controller is detached.
The broken lines in the figures depict portions of the breathing monitoring device which form no part of the claimed design. The dot-dot-dash broken lines encircling enlarged portions of the claimed design form no part thereof.