Apparatus for patient-controlled infusion

摘要

A reservoir is connected to a manually operable pump such as an aspirating syringe via a flow control tube which has a fine bore of accurately known size. Actuation of the syringe by the patient discharges a fixed volume of drug via a non-return valve to the patient. The syringe is refilled by a return spring drawing liquid from the reservoir at a rate controlled by the bore of the flow control tube, thus setting a maximum dosage rate.