A device introduced small volumes of fluid for delivery to a patient through a fluid line. The device includes a first arm adapted to receive a syringe and a second arm fluidly connected to an upstream reservoir that defines an internal volume adapted to receive a volume of fluid. The device includes a fluid obstruction mechanism configured to selectably block flow of fluid from the reservoir toward the patient, wherein the fluid obstruction mechanism transitions between a first state that permits fluid flow from the reservoir toward the patient and a second state that directs fluid flow from the syringe into the reservoir while blocking fluid flow from the reservoir toward the patient.