Methods and appratus for monitoring rotation of an infusion pump driving mechanism

Abstract

An infusion system, method and device for delivering therapeutic fluid to the body of a patient are disclosed. The device includes a dispensing unit having a peristaltic pump for dispensing therapeutic fluid to the body of the patient. The peristaltic pump includes a driving mechanism. The device further includes a monitoring mechanism (112, 114) for monitoring operation of the driving mechanism and dispensing of therapeutic fluid to the body of the patient.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application claims priority to U.S. Provisional Patent Application No. 60 / 928,751, filed May 11, 2007 and incorporates disclosure of this application herein by reference in its entirety.[0002]The present application also claims priority to U.S. Provisional Patent Application No. 60 / 928,815, filed on May 11, 2007, and entitled “A Positive Displacement Pump”, and U.S. Provisional Patent Application No. 60 / 928,750, filed on May 11, 2007, and entitled “Fluid Delivery Device”. This application incorporates disclosures of each of these applications herein by reference in their entireties.[0003]The present application also relates to the co-owned / co-pending U.S. patent application Ser. No. ______, and International Patent Application No. PCT / IL08 / ______, both filed on the even date herewith, and both entitled “A Positive Displacement Pump”, and U.S. patent application Ser. No. ______, and International Patent Application No. PCT / IL08...

AI Technical Summary

Benefits of technology

The present invention provides an improved method and device for monitoring the rotation of a driving mechanism of a miniature infusion pump. The device is appropriately-sized and cost-effective. It can detect electro-mechanical disassociation, motor malfunction, and no-flow or backflow in the pump. The device can be attached to the patient's skin and can be easily detached. It can also include a self-correction mechanism and alert the patient if the correction attempts fail. The invention also provides a solution for preventing or minimizing the occurrence of backflow in positive displacement peristaltic pumps. The device includes an encoder wheel and a light detector to monitor the rotation of the driving mechanism. Overall, the invention ensures that the patient is provided with required amounts of therapeutic fluid and prevents life-threatening drug under-dosing.

Problems solved by technology

Both basal and bolus volumes must be delivered in precise doses, according to individual prescription, since an overdose or under-dose of insulin could be fatal.

These devices represent an improvement over multiple daily injections, but nevertheless, they all suffer from several drawbacks, one of the main drawbacks is its large size and weight of the device, caused by the configuration and the relatively large size of the driving mechanism of the syringe and the piston.

This relatively bulky device has to be carried in a patient's pocket or attached to the belt.

These uncomfortable bulky devices with a long tube are rejected by the majority of diabetic insulin users, since they disturb regular activities, such as sleeping and swimming.

Furthermore, the effect of the image projected on a body of a teenager is unacceptable.

These devices also have several limitations: they are bulky and expensive, their high selling price is due to the high production and accessory costs, and the user must discard the entire device every 2-3 days, including relatively expensive components, such as driving mechanism and other electronics.

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These encoders occupy a large space and hence are not suitable for a miniature infusion pump.

Furthermore, when the encoder is located on the motor shaft it monitors only the rotation of the motor itself, and cannot directly monitor rotations of shafts and gears.

Moreover, it does not detect occurrences of electro-mechanical disassociation due to breakage of gears, dust, etc.

Another problem which exists in rotary peristaltic pumps is that the resulting delivery of fluid occurs in a series of pulses or surges, the frequency of which is equal to the frequency of the passage of successive rollers in contact with the delivery tube.

The effect is that fluid is delivered at a widely varying rate during a pump cycle and this can be unacceptable in infusion procedures in which uniformity of delivery rate is a requirement (e.g., insulin pumps).

Moreover, the continuous change in flow rate can cause instability in sensitive feedback control systems which are designed to ensure that fluid is delivered at a constant rate.

Having frequent periods in which there is no fluid flowing downstream, i.e., towards the patient's body, is extremely hazardous when dealing with therapeutic fluid such as insulin.

When an insulin pump is set to its minimal flow rate, it is likely that the patient will not receive any insulin at all.

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