Medication infusion system having optical motion sensor to detect drive mechanism malfunction

A system for use in a medication infusion system for monitoring and verifying proper operation of the medication infusion system, said medication infusion system being of the type which operates by engaging the plunger of a syringe to dispense medication to a patient, said system comprising:

• a drive motor having drive signals inputted thereto;
• mechanical drive means, driven by said drive motor, for driving the plunger of the syringe to dispense medication the patient;
• a reflective member having a pattern thereon of reflective and substantially nonreflective surface zones, said reflective member being movable with said lead screw to displace said reflective and nonreflective zones sequentially past a predetermined point;
• light source means for illuminating said predetermined point;
• reflection detector means for detecting the level of light reflected from said reflective member at said predetermined point and for generating an output signal representing said level of reflection;
• and
• controller means for comparing said output signal with the drive signals inputted to said drive motor and for responding thereto to indicate the operational state of said drive motor.

In an infusion pump having a drive motor, controller means for inputting drive signals to the drive motor, and at least one mechanical output component displaced by the drive motor and adapted to operate a syringe to deliver medication or the like therefrom in a controlled manner, a sensor-operated infusion pump safety monitoring system, comprising:

• a reflective member having a pattern thereon of reflective and substantially nonreflecting surface zones, said reflective member being movable with the mechanical output component to displace said reflective and nonreflective zones sequentially past a predetermined point;
• light source means for illuminating said predetermined point;
• and
• reflection detector means for detecting the level of light reflected from said reflective member at said predetermined point and for generating an output signal representing said level of reflection;
• said controller means including means for comparing said output signal with the drive signals inputted to the drive motor and for responding thereto to indicate the operational state of the drive motor, said controller means providing a fault signal when insufficient movement of said reflective member and the mechanical output component in relation to the drive signals inputted to the drive motor is detected;
• and
• means for providing an underinfusion alarm when said controller means provides said fault signal.

A medication infusion system including an arrangement for monitoring the operation of said medication infusion system to ensure that said medication infusion system is operating properly to cause medication to be dispensed to a patient, said system comprising:

• a housing including means for mounting a syringe having a plunger therein;
• a mechanical drive element mounted for driven movement in said housing;
• a drive wheel for driving said mechanical drive element;
• means for driving said drive wheel to drive said mechanical drive element;
• means mounted on said mechanical drive element for pushing said plunger into said syringe to dispense medication when said mechanical drive element is driven into movement;
• a reflective member having a pattern of reflective and substantially nonreflective surface zones thereon, said reflective member being mounted on said drive wheel to displace said reflective and nonreflective surface zones in sequence past a predetermined point;
• and
• photoreflective sensor for illuminating said predetermined point, and for detecting the level of reflection from said reflective member at said predetermined point to monitor movement of said reflective member with said drive wheel.