A mobile robot that includes a drive system, a controller in communication with the drive system, and a volumetric point cloud imaging device supported above the drive system at a height of greater than about one foot above the ground. The volumetric point cloud imaging device monitors a plurality of translations of points in the point cloud corresponding to the surface of a respiratory center of a breathing subject. The controller receives point cloud signals from the imaging device and issues an alert command based at least in part on the received point cloud signals from the identified respiratory center.
