An epidermal dressing includes an appliance for linking an electromagnetic spectrum sensor with a cannula administering an intravascular infusate. The appliance includes a body and a fitting coupled to the body. The body is configured to space the connector from the epidermis. The fitting includes a first arrangement that is configured to retain the electromagnetic spectrum sensor for sensing the infusate in perivascular tissue, and a second arrangement that is configured to release the electromagnetic spectrum sensor from the first arrangement.
