Abstract: A membrane dome switch is disclosed which includes a tactile feel regulator shim to provide an enhanced and consistent tactile feedback in response to fingertip switch depression. The membrane dome switch includes a conductive domed spring member mounted in a sandwich or laminant array between an underlying circuit layer having a conductive circuit pattern thereon and an overlying shield layer. Fingertip pressure applied to the shield layer is effective to deform the spring member to momentarily close a circuit path on the circuit layer. The tactile feel shim is interposed between the spring member and the overlying shield layer, and functions to provide improved tactile feedback sensation during switch operation.

Abstract: An insertion set is provided for transcutaneous placement of a sensor such as a glucose sensor at a selected site within the body of a patient. The insertion set comprises a slotted insertion needle extending through a mounting base adapted for mounting onto the patient's skin. A flexible thin film sensor includes a proximal segment carried by the mounting base and defining conductive contacts adapted for electrical connection to a suitable monitor, and a distal segment protruding from the mounting base with sensor electrodes for transcutaneous placement. The proximal and distal segments of the sensor are linearly offset or misaligned, with the distal segment fitted within the insertion needle for transcutaneous sensor placement with the needle as the mounting base is pressed onto the patient's skin. The insertion needle can then be withdrawn to leave the sensor distal segment at the selected insertion position with the sensor electrodes in contact with patient blood or other extracellular fluid.

Abstract: An improved method is provided for making thin film electrochemical sensors, such as subcutaneous glucose sensors used to monitor blood glucose levels in a diabetic patient. The fabrication method comprises placing a thin film base layer of insulative material onto a rigid flat substrate, with a curable adhesive interposed between the perimeter of the base layer and substrate to define a shallow cavity underlying a central portion of the base layer. The subassembly is subjected to heat and pressure to cure the adhesive, resulting in air expulsion from the cavity such that the central portion of the base layer is drawn into intimate contact with the substrate. Appropriate conductor elements for one or more sensors are formed on the base layer as by conventional contact mask photolithography, and a thin film cover layer of insulative material is applied thereover with apertures in the cover layer exposing distal end sensor electrodes and proximal end contact pads.

Abstract: A data transfer system is provided for communication with an infusion pump of the type used for programmable delivery of medication such as insulin to a patient. The data transfer system includes a communication station having a shaped pocket formed therein for seated reception of the infusion pump. Optical communication members including light emitting and detecting devices mounted on the pump and station are aligned for two-way data transmission when the pump is seated within the station pocket. The communication station can be used directly to monitor data received from the pump, and to transmit reprogrammed data to the pump, as desired. Alternately, the communication station can provide a data relay link to a remote site such as to a computer via a computer data cable, or a modem.

Abstract: A protective case is provided for receiving and supporting a medication infusion pump of the type used to deliver a selected medication such as insulin to a patient. The protective case comprises a transparent housing of impact resistant material for slide-fit reception of the pump, in combination with a seal cap for removable mounting onto the housing to define a substantially waterproof pump enclosure. The seal cap is formed from a resilient shock absorbing material and cooperates with additional shock absorber elements to resiliently support the pump within the housing. A catheter port is formed in the seal cap for sealed passage of a catheter tube extending from the pump to the patient. A belt clip is removably mounted onto the assembled case to prevent seal cap separation from the housing, and to provide a convenient structure for belt mounting of the protective case onto the body of patient.

Abstract: A method is provided for reconditioning a medication infusion pump by removal of accumulated medication deposits and the like to restore pump performance without requiring surgical removal of an implanted pump from a patient. The reconditioning process comprises sequential delivery of a buffer solution and a rinse solution to internal pump flow passages. The rinse solution is effective to dissolve medication deposits and the like within narrow pump flow passages before the rinse solution is neutralized by intermixing with the buffer solution. Dissolution of accumulated medication deposits results in restoration of pump performance substantially to original product specifications.

Abstract: A device for use as a subcutaneous injection set is disclosed which has a soft cannula through which a selected medication can be administered to a patient, wherein the soft cannula is adapted for transcutaneous placement by an insertion needle substantially without crimping or kinking. The cannula is supported by and protrudes outwardly from a housing adapted to receive the selected medication. The insertion needle is initially inserted through a septum on the housing and further through the cannula to provide a rigid structure to insert the soft cannula through the patient's skin. The insertion needle and cannula are constructed to prevent longitudinal slippage of the cannula on the needle during the insertion process, thereby preventing undesired crimping or kinking of the soft cannula. After insertion, the needle is withdrawn from the cannula and housing to permit medication delivery to the patient.

Abstract: A kit is provided for use in refilling a medication infusion pump of the type adapted for implantation into the body of a patient. The kit comprises a syringe having a plunger mounted for reciprocation within a syringe barrel having a manually operable control valve mounted at a nose end thereof. The syringe further includes a lock for retaining the plunger subsequent to retraction motion with the control valve closed to pull and maintain a vacuum within the syringe barrel. With this construction, the syringe can be connected transcutaneously with a medication reservoir within an implanted infusion pump to aspirate residual medication from the pump. Alternately, the syringe can be used to degas medication within the barrel preparatory to transcutaneous delivery to the pump reservoir. In either case, the syringe is designed for facilitated and safe manipulation to permit rapid pump aspiration and refill at periodic intervals according to patient requirements.

Abstract: An improved process and related apparatus are provided for filling a pressure reservoir of an implantable medication infusion pump with a selected pressure fluid, wherein the pressure reservoir is separated by a movable wall from an adjacent medication chamber. The improved filling process includes vacuum-draw filling of the pressure reservoir with relatively purified pressure fluid in liquid state. The specific quantity of pressure fluid within the pressure reservoir is thereafter calibrated by filling the adjacent medication chamber with a calibration fluid at a predetermined positive pressure, thereby expelling excess pressure fluid from the pressure reservoir. The pressure reservoir is then sealed and the performance characteristics thereof are tested under simulated implantation conditions to confirm the capability of the pressure reservoir to maintain medication within the medication chamber under substantially constant pressure conditions.

Abstract: An improved subcutaneous injection set is disclosed which has a soft cannula for subcataneous delivery of a selected medication to a patient. The cannula is supported by and protrudes outwardly from a cylindrical support hub of a housing adapted to receive the selected medication. A flanged base end of the cannula is disposed within the housing and is captured by a swaged lock rim to retain a sealing gasket under compression against an annular seat within the support hub, thereby preventing leakage of the medication through the hub and about the exterior of the cannula.

Abstract: An implantable medication infusion pump is provided which utilizes an improved and simplified pressure reservoir to maintain a selected medication in liquid form within a pump housing under a substantially constant pressure. The pressure reservoir comprises a hollow structural enclosure having at least one flexible resilient wall and is adapted to be filled with a selected quantity of a pressure fluid, such as a selected fluorocarbon in a liquid-vapor state, prior to mounting of the reservoir as a structural unit into the infusion pump housing. Within the pump housing, the flexible reservoir wall defines one side of a medication chamber, with the pressure fluid undergoing appropriate change of state to expand or contract the reservoir in a manner maintaining the medication under a substantially constant pressure.

Abstract: A pressure diaphragm installed in a disposable cassette for use on a main pump unit is disclosed which allows pressure downstream of a fluid pump to be measured with a high degree of accuracy. The pressure diaphragm is located over a raised cylindrical pressure plateau, and is spaced away from the plateau on the top and on the sides thereof to allow for a free movement of the pressure diaphragm. Fluid flow is from one side of the pressure plateau to the opposite side, with fluid flowing between the pressure diaphragm and the top and sides of the pressure plateau, as well as through a channel disposed in the pressure plateau.