Abstract: A connector block assembly for electrically connecting a proximal ring electrode of a bipolar pacemaker lead to the pacemaker. The connection is made in a way that maintains secure electrical contact and that prevents the delicate proximal ring electrode from being damaged or deformed. The pacemaker includes a connector block having a channel therethrough into which the proximal ring electrode is inserted. A C-ring is sandwiched between the ring electrode and an inner wall of the connector block's receiving channel. A setscrew adjustably forces the C-ring against the ring electrode. Mechanical stop means limit the transverse movement of the C-ring, thereby preventing the ring electrode from being deformed, while still maintaining a firm grasp of the ring electrode between the C-ring and the connector block. An alternative embodiment employs a resilient spring to firmly hold the ring electrode in electrical contact with the connector block.

Abstract: An injection set for delivering a fluid to a subcutaneous injection location in a patient is disclosed which has a soft cannula projecting from a bottom surface of a holding pad. An insertion needle is initially inserted through a septum located between a catheter hub and a retaining cap mounted on the holding pad. The insertion needle extends through a fluid chamber defined by the septum and the catheter hub and then through a lumen of the soft cannula, with the sharpened tip of the insertion needle extending beyond the end of the soft cannula when the insertion needle is fully inserted. The insertion needle, which allows priming of the injection set, may be removed following installation of the injection set without kinking of the soft catheter, and fluid may be supplied to the injection set for delivery to the patient.

Abstract: Isolation circuitry for use with diagnostic ECG devices provides high common mode rejection and low leakage current using optoisolators in conjunction with an isolating operational amplifier. A predetermined pattern of binary input signals selectively energizes, via the optoisolators, a plurality of switches interposed between electrodes positioned on a patient's skin and the isolating operational amplifier. This selection couples a predetermined combination of electrodes to the isolating operational amplifier to provide the desired ECG output. The output from the isolating operational amplifier may be coupled directly to a recording device or coupled to a circuit which processes the ECG signal before the signal is recorded.

Abstract: A protection circuit for an implanted telemetry circuit used to telemeter ECG or other low level signals sensed on the same lead whereon high level stimulation or other signals may also appear. The protection circuit includes a first FET switch that selectively connects a buffered monitoring point of the lead to the input of the telemetry circuit whenever a telemetry mode of operation is desired. A second FET switch switchably connects the buffered monitoring point to ground in the presence of any high level signals appearing on the lead, thereby preventing such high level signals from being applied to the telemetry circuit.

Abstract: A protected output switch for an implantable medical device, such as a pacemaker, is disclosed. Through this output switch, a stimulation pulse is delivered from an internal storage element to an output terminal. The output switch includes a first N-channel MOSFET switch having its source terminal connected to the internal storage element and its drain terminal connected to the output terminal. The gate terminal of the N-channel MOSFET switches is connected to approriate logic switching signals. Included as part of the output switch is a second N-channel MOSFET switch having its source terminal connected to the P-well terminal of the first N-channel MOSFET switch, its drain terminal connected to the internal storage element, and its gate terminal connected to the output terminal. This second switch serves to block any potentials, whether internal or external, from being applied to the base of a parasitic NPN bipolar transistor that exists within the output switch.

Abstract: An injection set for use with an external infusion source of fluid such as insulin is disclosed which injection set is constructed using multiwall tubing. The interior of the multiwall tubing is made of a material which is completely insulin compatible, while the exterior of the multiwall tubing is made of a material which may be solvent bonded. The multiwall tubing facilitates solvent bonding installation of an insert molded needle assembly and a connector to the ends of the tubing without necessitating the use of and incurring the disadvantages of epoxy bonding.

Abstract: A valve for use in medical applications is disclosed which is a highly precise, passive, one-way valve which makes an excellent inlet valve or outlet valve in a drug infusion pump. The valve operates with a very small forward pressure, requires only a small amount of fluid in the valve chamber, and operates in a positive and predictable fashion, even after an extended shelf life. The valve, may be inexpensively molded in one piece, thereby facilitating construction of a disposable pump, and may be installed with the portion of the pump housing contacting the top surface of the valve being flat, thereby further reducing manufacturing costs.

Abstract: A programmable infusion pump apparatus having a power supply (4, 11), a first circuit (6) responsive to the and assisting the power supply (4), power generating circuit (8) for generating sufficient power to drive a pump drive mechanism (12), a power storage circuit (10) for storing the power generated by the power generating circuit (8), a sensing system (16) for sensing stored power levels and the condition of the power supply (11), a microprocessor (18); a plurality of actuators (24, 26, 28, 30) for display and changing parameter values stored in RAM of the microprocessor (18), a memory (34) operably connected to microprocessor (18); display screen (40) for displaying parameter values and other information concerning the apparatus and a tone transducer (22) for providing an audio output from the apparatus to indicate certain conditions.

Abstract: In an implantable device, transmission and reception of digital information is accomplished as well as the transmission and reception of analog information. The analog signal is FM modulated for transmission and the digital signal is phase modulated for transmission. The FM modulated signal is used as a clock in the phase encoding of the digital signal and thus provides a signal simultaneously carrying analog and digital information. Means for reception of the analog and digital information is taught. The use of PSK (phase shift keying) as the phase modulation scheme for transmission and reception is also taught.

Abstract: A solenoid drive apparatus for driving a lead screw of an External Infusion Pump (1) having a housing (302), solenoid winding (356) within the housing (302), a solenoid armature (358) which is driven by the field of the solenoid winding (356), push rod (362) which is driven by the armature (358), pawn (314) which is driven by push rod (362), a first pawl (320) which is driven by pawn (314) and a second pawl (326) which is an antibacklash device, a ratchet wheel (318) having teeth (319) around its periphery and engaged by the first pawl (320) and the second pawl (326) and the drive shaft (316) which is drawn by the ratchet of the ratchet wheel (318).

Abstract: A valve, suitable for use in small medical devices and which can readily be made of medical grade materials, comprises an elastic diaphragm stretched over a protruding surface, preferably of spherical or convex shape. The diaphragm has a ring of holes concentrically around a hole in the protruding surface. A mating recess, connected to a conduit, fits over the protruding surface. The elastic material is held in place at or near the opening of the recess. The holding structure may also serve to seal the valve. A dual arrangement provides an input and an output valve in combination.

Abstract: The present invention is an introducer catheter apparatus having a body with a first bore along a longitudinal axis and a second bore in fluid communication with the first bore and extending from the first bore to the exterior surface at the side of the body, a fluid delivering means disposed on the second bore as the exterior surface of the body and the fluid communication with the second bore, and a flexible hollow tube means disposed in the first bore, a deformable sealing means disposed in the first bore between the second end of the body and the position within the first bore where the second bore connects to the first bore and a retractable needle means extends through the body including the deformable sealing means and a flexible hollow tube means and the tip of said needle when therein disposed extends past a distal end of the flexible hollow tube means.

Abstract: The present invention is a sensing amplifier circuit for a tissue stimulator (72) for supplying or attenuating far field signal voltage artifacts comprising a full differential amplifier having a first (94, 136) and second (96, 142) stage amplifiers for respectively receiving a second and first signal voltage output from a sensing mean (80, 82), and a switch means for controlling an input of the second signal voltage output from said sensing means to the first stage amplifier (94, 136).

Abstract: A fluid flow monitoring method and device for a drug injector (10). More particularly, a flow monitoring device is disclosed for an implantable or externally located drug injector having a conduit (18) for carrying fluid from a reservoir (14) to a user's body. In an exemplary embodiment, the drug injector (10) is of the type having a first valve (22) located proximal to the reservoir (14) for blocking the flow of fluid through the conduit (18), a second valve (24) located distal to the reservoir (14) for blocking the flow of fluid through the conduit (18), and a pump (20) located between the first and second valves (22) and (24) for alternately increasing and decreasing the volume of a conduit portion (68) located between the first and second valves (22) and (24). The valves are controlled so that the first valve (22) is open and the second valve (24) closed when the pump (20) is increasing the volume of its associated conduit portion, thereby drawing fluid from the reservoir (14) into the conduit (18).

Abstract: A method and apparatus for monitoring the status of a battery in an implantable device for a human, the device being a tissue stimulator, drug dispensing apparatus, or the like. More specifically, a battery monitoring apparatus is disclosed whereby a user is sensually stimulated whenever an implanted battery exhibits predetermined characteristics. In one embodiment, the internal resistance of a battery is periodically monitored by loading the battery at predetermined intervals. When the internal resistance exhibits a predetermined characteristic, a battery alarm circuit is activated which causes a small voltage differential to be applied under and across the skin of the user, thereby creating a mildly tingling sensation in his skin. This tingling sensation alerts the user that the battery needs to be replaced or recharged. A magnet is provided for externally disabling the monitoring apparatus after the user has been alerted that the battery needs replacement.

Abstract: A magnetic field concentration means and method for use in conjunction with an implanted device responsive to an externally generated magnetic field. More specifically, a magnetic field concentrator is disclosed which includes a metallic slug located between a magnetic field generator and a magnetic pick-up coil contained in the implanted device. The metallic slug concentrates magnetic lines of flux at the pick-up coil. In a specific embodiment, the implanted device is an intracranial pressure monitoring device (ICPM) which is located within an orifice formed in a recipient's skull. The magnetic field concentrator is positioned within the orifice and directly above the ICPM, thereby concentrating magnetic flux lines at the ICPM. Two configurations of the slug are disclosed, one being in the form of a cylinder and the other being in the form of a truncated cone.

Abstract: A battery monitoring means for an implantable tissue stimulator in which a signal related to the internal impedance of an implanted battery is telemetered to an external receiving means. More specifically, the implanted battery is loaded by a varible load until current flowing through the battery lowers its output voltage until it has a predetermined relationship with respect to a reference voltage. The current flowing through the battery to achieve the predetermined relationship is directly related to the internal impedance of the battery. A voltage related to the value of this current is then telemetered to the external receiving means. In a specific embodiment, the variable load is a field effect transistor (FET) connected as a source follower. The impedance of the FET is controlled by the output of an operational amplifier having as inputs the reference voltage and a voltage related to the output voltage of the battery.

Abstract: An apparatus is disclosed for use with teletypewriter consoles in teleprinter communication networks for providing transmission time information during message preparation; namely, the number of whole minutes of message time plus either the number of characters remaining to the next full minute, or tenths of minutes of additional message time used. Such information enables the user to anticipate and thus optimize message time for which he is charged in a rounding-up charge procedure commonly used in such teleprinter communication networks. A preferred embodiment consists of a microprocessor-based computer for converting each character on a perforated tape to a sub-unit of time corresponding to the appropriate transmission rate of either TELEX or TWX network services.

Abstract: An apparatus and method for displaying and controlling parameters for a programmable living tissue stimulator system. Visual indicators corresponding to control parameters or signals for the tissue stimulator system are divided into a predetermined number of groups. One of these groups containing a parameter to be selected for the tissue stimulator system is selected, the selected group being identified by a visually identifiable indication. A parameter within that group is then selected for transmission to an implanted memory means which controls an implanted tissue stimulator. In a specific embodiment, a matrix of visual indicators consisting of R rows and S columns is provided, each visual indicator corresponding to a specific control signal. A means is provided whereby at least one visual indicator contained in a selected R row will blink on and off, the blinking indicators identifying control signals to be selected for the implanted memory means.

Abstract: A battery life extender for use in an implantable tissue stimulator. The tissue stimulator comprises a battery which powers a volatile memory, control circuits and a pulse output circuit all of which are connected in parallel across the battery. The invention provides a means for controlling current through the output circuit as a function of a difference voltage between the battery output voltage and a reference voltage. The reference voltage and battery voltage comprise inputs to a differential amplifier which in turn provides an output control voltage which controls a field-effect transistor (FET) connected in series with the output circuit and battery. As this control voltage rises, current through the field-effect transistor is reduced, thereby reducing the amplitude of the pulses from the output circuit and the current drain from the battery.