Abstract: An occlusion detection system detects an occlusion in a fluid path of an infusion pump. The infusion pump is for delivering fluid to a user. The infusion pump includes a housing, a motor, a reservoir, one or more drive train components, a sensor, and an electronics system. The motor is contained within the housing. The reservoir contains the fluid to be delivered. The one or more drive train components react to stimulus from the motor to force the fluid from the reservoir into the user. The sensor is positioned to measure a parameter associated with the motor or a drive train component, and the sensor produces three or more output levels across a range of measurements. The electronics system processes the sensor output levels to declare when an occlusion exists.

Abstract: In a fluid delivery system for delivering a fluid into an individual's body, a leak detection system indicates that the fluid has leaked outside a normal fluid path of the fluid delivery system, such as near an infusion site or a fluid-filled reservoir. Preferably, the leak detection system includes a chemical positioned near the infusion site that reacts with preservatives in the leaking fluid to generate a highly visible, brightly colored, chemical complex. Alternatively, mechanical, electro-optical, electrochemical, electrical or other chemical systems may be used to detect the presence of fluid that is leaking near the infusion site. Further, the leak detection systems may be used to detect the presence of fluid that is leaking from or near other locations within the fluid delivery system, such as on or near a fluid-filled reservoir, or a flexible tube coupled between the reservoir and the infusion site.

Abstract: An occlusion detection system detects an occlusion in a fluid path of an infusion pump. The infusion pump is for delivering fluid to a user. The infusion pump includes a housing, a motor, a reservoir, one or more drive train components, a sensor, and an electronics system. The motor is contained within the housing. The reservoir contains the fluid to be delivered. The one or more drive train components react to stimulus from the motor to force the fluid from the reservoir into the user. The sensor is positioned to measure a parameter associated with the motor or a drive train component, and the sensor produces three or more output levels across a range of measurements. The electronics system processes the senor output levels to declare when an occlusion exists.

Abstract: A selectively protected electrical system includes or operates with a power source, a load, a power driver circuit for controllably transferring power from the power source to the load, the power driver circuit being encapsulated in a potting material, and a controller for enabling and disabling the power driver circuit, the controller being un-encapsulated by the potting material. If a contaminant induced electrical fault occurs in the selectively protected electrical system, the electrical fault is more likely to occur in the un-encapsulated controller, such that the selectively protected electrical system is disabled. The contaminant is inhibited from contacting and inducing an electrical fault in the power driver circuit, thus providing for a controlled failure of the selectively protected electrical system.

Abstract: An infusion leak detection system indicates that a fluid to be delivered into an individual's body has leaked near an infusion site. The infusion site is at a location where a delivery element, such as a cannula, needle, or the like, penetrates an individual's body. Preferably, one end of the delivery element is attached to a delivery device and the other end is inserted through an individual's skin terminating in an individual's subcutaneous tissue. The delivery element establishes fluid communication between the delivery device and the individual's subcutaneous tissue. In alternative embodiments, the delivery element may terminate in an other tissue such as, muscle, organ, inter-peritoneal, intra-peritoneal, or the like. The delivery device is attached to the surface of the individual's skin.

Abstract: An improved pump, reservoir and reservoir piston are provided for controlled delivery of fluids. A motor is operably coupled to a drive member, such as a drive screw, which is adapted to advance a plunger slide in response to operation of the motor. The plunger slide is removably coupled to the piston. The piston comprises a first member and a second member. The first member has an external proximate side and an external distal side. The external proximate side is adapted to contact the fluid and is made of a material having a first stiffness. The second member has a first side and a second side and is at least partially disposed within the first member. The first side of the second member is adjacent to the external proximate side of the first member and is made of a material having a stiffness which is greater than the first stiffness.

Abstract: An external infusion device that infuses a fluid into an individual's body includes a housing, a reservoir, a drive system, a power supply, electrical elements, and a tab. The reservoir contains the fluid, and the drive system forces the fluid from the reservoir. The electrical elements control the power to the drive system to regulate the rate that fluid is forced from the reservoir. The tab mates with the housing, and contains at least one electrical element. The tab is removable, and may be replaced with a different tab. The different tab may change the rate fluid is forced from the reservoir. A tab may be removed from one external infusion device and installed in a different external infusion device. The tab may be limited to use in a predetermined number of external infusion devices and may include a power supply.

Abstract: An occlusion detection system detects an occlusion in a fluid path of an infusion pump. The infusion pump is for delivering fluid to a user. The infusion pump includes a housing, a motor, a reservoir, one or more drive train components, a sensor, and an electronics system. The motor is contained within the housing. The reservoir contains the fluid to be delivered. The one or more drive train components react to stimulus from the motor to force the fluid from the reservoir into the user. The sensor is positioned to measure a parameter associated with the motor or a drive train component, and the sensor produces three or more output levels across a range of measurements. The electronics system processes the senor output levels to declare when an occlusion exists.

Abstract: A processing system and method are provided for deriving an improved hemodynamic indicator from cardiac wall acceleration signals. The cardiac wall acceleration signals are provided by a cardiac wall motion sensor that responds to cardiac mechanical activity. The cardiac wall acceleration signals are integrated over time to derive cardiac wall velocity signals, which are further integrated over time to derive cardiac wall displacement signals. The cardiac wall displacement signals correlate to known hemodynamic indicators, and are shown to be strongly suggestive of hemodynamic performance. An implantable cardiac stimulating device which uses cardiac wall displacement signals to detect and discriminate cardiac arrhythmias is also provided.

Abstract: An improved sensor and related method for multi-axial measurement of motion for an implantable medical device is disclosed. The sensor has a wide variety of applications, including use as a cardiac wall motion sensor or a physical activity sensor. The sensor includes first and second conductors over which the motion measurements are made. A first transducer provides a first motion measurement indicative of sensor acceleration during a first phase, while a second transducer provides a second motion measurement indicative of sensor acceleration during a second phase. The first and second transducers are connected in parallel so as to provide the first and second motion measurements to an implantable medical device over the first and second conductors. The first and second phases are non-overlapping periods of time so that the motion measurements from each transducer are time division multiplexed. The sensor provides motion measurements that may either be compensated or uncompensated for temperature effects.

Abstract: A connector assembly mounted on an implantable cardiac stimulation device has an actuator mechanism for fixing and sealing electrical leads inserted into lead receptacles within the connector assembly without the use of setscrews. Fixing and sealing of the leads is accomplished by compressing resilient lead lock seals of O-ring shape, disposed in annular recesses, with lip portions of a plunger drawn toward the molded support by the actuator mechanism. In a first embodiment of the actuator mechanism, rotation of a cam actuator transversely journaled within the support, using a torque wrench or similar tool, moves a cam slide attached to the plunger through a fixed displacement between lock and unlock positions as an offset camming portion of the actuator engages the surfaces of a slot within the cam slide.

Abstract: An accelerometer-based, multi-axis physical activity sensor for use with a rate-responsive pacemaker, and a method for fabricating the sensor, are provided. The multi-axis physical activity sensor includes a cantilever beam having a film of a piezoelectric polymer adhered to each surface of an electrically conductive substrate. The piezoelectric films are highly resistant to fracturing during manufacture and in use, and they provide a strong output signal when stressed in response to bodily accelerations. A mass is mounted to a free end of the cantilever beam, and is substantially offset with respect to a planar surface of the beam so as to impart multi-axis sensitivity to the physical activity sensor. The accelerometer-based, multi-axis physical activity sensor provides an output signal that is communicated to pacemaker circuitry using a pair of electrical conductors.

Abstract: Implantable leads incorporating accelerometer-based cardiac wall motion sensors, and a method of fabricating such leads, are provided. The cardiac wall motion sensors transduce accelerations of cardiac tissue to provide electrical signals indicative of cardiac wall motion to an implantable cardiac stimulating device. The implantable cardiac stimulating device may use the electrical signals indicative of cardiac wall motion to detect and discriminate among potentially malignant cardiac arrhythmias. In response to a detected abnormal cardiac rhythm, the cardiac stimulating device may deliver therapeutic electrical stimulation to selected regions of cardiac tissue.

Abstract: An improved implantable cardiac stimulating device that performs cardiac wall motion-based automatic capture verification system is provided. Pacing pulses of varying energy content are administered to a patient's heart, and the response of the patient's heart is sensed by a cardiac wall motion sensor. The cardiac wall motion sensor provides a signal which is analyzed to determine the patient's capture threshold, defined as the minimum amount of electrical stimulation required to evoke a cardiac contraction. The device then sets the amount of electrical stimulation at a level safely above the measured capture threshold. Capture verification may be performed at predetermined time intervals, on demand, or upon the occurrence of a significant cardiac event. Capture verification can also be performed on every pacing pulse delivered by the implantable cardiac stimulating device.

Abstract: A system and method for a pacemaker are provided, for using cardiac wall motion sensor signals to provide hemodynamically optimal pacing therapy to patient at rest, and for providing rate-responsive pacing therapy. The cardiac wall motion sensor signals are provided by an implantable lead that incorporates an accelerometer for measuring cardiac mechanical activity. The cardiac wall motion sensor signals are processed to derive cardiac wall velocity signals and cardiac wall displacement signals. The derived signals are further processed to derive physiologic parameters indicative of cardiac performance, including stroke volume, contractility, pre-ejection period, and ejection time. The physiological parameters, in turn, are used by the pacemaker to provide hemodynamically optimal pacing therapy at rest, and rate-responsive pacing therapy.

Abstract: Implantable leads incorporating accelerometer-based cardiac wall motion sensors, and a method of fabricating such leads, are provided. The cardiac wall motion sensors transduce accelerations of cardiac tissue to provide electrical signals indicative of cardiac wall motion to an implantable cardiac stimulating device. The implantable cardiac stimulating device may use the electrical signals indicative of cardiac wall motion to detect and discriminate among potentially malignant cardiac arrhythmias. In response to a detected abnormal cardiac rhythm, the cardiac stimulating device may deliver therapeutic electrical stimulation to selected regions of cardiac tissue.