A wearable medical device comprising an annular housing configured to attach to a wrist of a patient. The wearable medical device having a first receptacle attached to the annular housing for receiving a first portion of a tube of an intravenous delivery system. The wearable medical device comprising a flow regulator attached to the annular housing and in contact with the first portion of the tube, where the flow regulator is configured to modify a geometric characteristic of the first portion of the tube. The wearable medical device further comprising a wireless transmitter for communicating with a user console.