Executive Summary

Today more than 20.8 million people, almost 7% of the United States’ population, have diabetes. For those patients that must inject themselves several times each day, ultra-fine needles have been developed in order to minimize the pain associated with multiple injections. These needles, unfortunately, have the tendency to break or bend during insulin withdrawal or injection. The majority of those with diabetes currently over 60 years of age, have several unique problems concerning the use of ultra-fine needles during insulin withdrawal and injection that must be addressed.

The final design concentrates on stabilizing the syringe during the insulin withdrawal process from the vial, while also utilizing a locking mechanism to ease injection into the skin. The design incorporates mechanical elements that allow the syringe to clip into a groove, while the vial is held in a cradle by two elastic bands. The device is reusable, easy to use, while also being lightweight, portable, inexpensive, and compatible with standard insulin syringes and vials. The relative cost of each device is cheap enough that every diabetic patient could obtain the device easily. To ensure precision of the device, mechanical tests were performed to obtain data showing deflection angles of the needle at the various stages of the withdrawal/injection process. Statistical methods were then used to verify the accuracy of the tests performed.

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Introduction

For those patients that must inject themselves several times each day, ultrafine needles have been developed in order to minimize the pain [1]. However, these extremely thin needles have a tendency to bend or break if the patient does not have a strong, steady hand. The problem lies in the balance between having extremely thin needles to minimize pain versus strong needles that do not bend or break, especially during injections.

This problem of insulin injection stability is large, affecting millions of people in the United States alone. For example, today more than 20.8 million people, almost 7% of the United States’ population, have diabetes. The majority of those with diabetes are currently in the 60 years or older group, with almost 21% of those older than 60 afflicted with the disease as seen in Figure 1 [2]. The fact that so many patients are elderly presents several unique problems that must be addressed when it comes to safety during insulin injections.

These problems are, specifically, based around the fact that elderly patients are more likely to have some sort of disability in the hands such as rheumatoid arthritis or are unable to hold a syringe steady and inject themselves without bending or breaking the needle. According to the NDIC, almost 70% of older people with diabetes also suffer from some sort of nervous system damage [2]. This damage can result in impaired sensation in the hands or feet, carpal tunnel syndrome, and other nerve problems that have a detrimental affect during injections.

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Design Objectives

This document proposes the development of a new device to meet current needs regarding the stabilization of ultra-fine insulin needles. A device will be designed, prototyped, and tested robustly within the next three to four months. The main design objectives include:

1. Device must be able to stabilize ultra-fine, 30 gauge, needle while maintaining integrity of needle.
2. Must be reusable and easy to use.
3. Device must be lightweight, portable, inexpensive, and be compatible with standard insulin syringes and vials.
4. Robust testing with statistical evaluation of results reliable within 95%.

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References:

1. Arendt-Nielsen, L; Egekvist, H; Bjerring, P. "Pain following controlled cutaneous insertion of needles with different diameters. Somatosenory and Motory Research. 2006 Mar-Jun; 23(1-2):37-43.
2. "National Diatbetes Statistics." National Diabetes Information Clearinghouse, National Institute of Health. [http://diabetes.niddk.nih.gov/] Accessed on February 10, 2008.