Sterilizable medication infusion device with dose recharge restriction

Abstract

A subcutaneously implantable medication infusion device includes a variable capacity reservoir for receiving and storing fluid medication for delivery to a catheter which directs the medication to a specific infusion location in the body. A control assembly is interposed between the reservoir and the catheter to facilitate and control the transfer of the medication from the reservoir to the catheter in a safe and efficient manner. The control assembly includes a self-recharging pump and a normally closed valve, both of which are manually actuable by percutaneous pressure when subcutaneously implanted, and a one-way valve positioned within a primary fluid conduit between the pump and the normally closed valve. The control assembly is constructed to permit the infusion of a measured bolus of medication on demand through manual percutaneous manipulation of the control assembly. A capillary-like fluid pathway through which the recharge fluid must pass before entering the pump, is provided to limit the rate the pump is recharged with medication, and to restrict the total amount of medication which can be pumped into the catheter over a given period of time. An alternate fluid conduit extends between the pump and the normally closed valve, and a Porex-type plug situated within the alternate fluid conduit prevents the flow of liquid medication therethrough under normal use conditions, but permits the passage of gasses through the alternate fluid conduit to facilitate steam autoclave sterilization of the pumping chamber.