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The Greening of Medical Product Design


Posted by mddiadmin on August 1, 2008
How to make medical device products more sustainable.

PRODUCT DEVELOPMENT INSIGHT

The original product is adequate, but a redesign could save money for the OEM.
An initial design change results in a lighter handle.
A smaller wand and base in the final

version is sleeker and wastes less material.

The green writing is on the wall: it is time for medical manufacturers to conside the sustainability of their products, packaging, and production processes. In the consumer world, Wal-Mart is undergoing a major effort to adopt sustainability and even hired the ex-head of the Sierra Club as a consultant on this topic. Clorox recently announced its Green Works line of greener household cleaning products. Companies with a strong presence in the medical field like Kimberly-Clark and Philips have long been doing something about the issue.

In this author's experience, countless medical product consumers around the country have revealed their concerns about sustainability in interviews. They consistently bring up the topics of global warming or green in discussions about new products that, as recently as two years ago, would have been solely focused on efficacy and usability.

Even if you are not doing something about getting greener, your customers are. Alegent Health, a company with nine hospitals and 8600 employees, has recently named a vice president of sustainability. When faced with a choice of medical products of similar cost and efficacy, it is likely that customers will purchase the greener product, especially if manufacturers have added green to their brand attributes in a way that customers see has real meaning.

Sustainability broadly means considering the environmental effect of a product throughout its life cycle, not just in its creation and initial use. And it is a daunting topic for the uninitiated. Although RoHS and other legislation in Europe have brought some sustainability issues to the forefront, it is understandable that many medical manufacturers have been reluctant to embrace sustainability. The device industry is notoriously slow to make changes. In addition, the industry is sometimes exempted from the legislative restrictions required in the consumer marketplace and therefore less likely to pursue such change. Further, sustainability has an image of increasing costs.

The good news is that there is a lot of low-hanging sustainability fruit that can be harvested by applying common sense principles and a sustainability-conscious eye to the product lifecycle.

This article presents practical advice to designers and manufacturing engineers about how to improve the sustainability of device products. Be prepared to be surprised, as have many in the consumer world—you might just find out it makes good business sense too.

Start Here: Map The Product Lifecycle

Understanding how medical manufacturers can affect sustainability requires mapping a product's lifecycle. This includes raw material extraction; all the processing and manufacturing; actual use; and disposal, reuse, or recycling.

Creating a sustainable product is an attempt to reduce the environmental footprint at each stage with some kind of change. It is up to your company to decide what constitutes a better, or greener design. Changes do not have to be massive to have a positive effect. For instance, Philips Healthcare allows a product to be considered a Green Flagship if it achieves an improvement over its predecessor or competitor of 10%, but a review of their products with this status indicate that most achieved improvements in the 25% to 35% range.1

OEMs usually focus on improving efficacy and usability, and minimizing trauma and cost. Like these factors, sustainability can have the biggest influence at the very beginning of the product's conception. Many sustainable qualities of a product are baked in during the innovation and design stage.

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For medical products, the business model is also important. For example, a onetime-use disposable employs more resources than a re¬usable product. Of course there may be clinical, product, or sterility issues that require disposability. Keep in mind that because of such factors, the approaches to sustainability from the general consumer or industrial world do not always translate well to medical products.

Quantifying Design Alternatives

Once a specific device's lifecycle is understood, and OEM can begin identifying the places to lower its environmental impact. To determine which ideas are the best to pursue, the development team should quantify the effect of the various choices and then find what is right for the product and the company.

One way of enumerating a particular design's impact is to use software such as Life Cycle Assessment (LCA). This software draws on carefully researched databases, allowing manufacturers to estimate the effect of one type of plastic over another, the weight and material type of packaging, or shipping options Leaders in LCA software are European companies with products such as SimaPro and GaBi. (Demonstrations of these products are available via Web download.)

Although larger companies may already own such software or think nothing of purchasing it and training people on how to use it, the software may not be the right place for most device manufacturers to start.

Hans van der Wel, the Philips Healthcare's manager of Ecodesign & Sustainability helps run their Green Flagship program. He says the best method for starting out is to “keep it simple. Start with a spreadsheet based on simple indicators. We call ours Green Focal Areas [and] include qualities like the amount of materials, energy, and hazardous substances used.” Van der Wal explains, “Top management needs to be behind the initiative, and you may need to hire consultants to help at the start.” He says it took Philips ten years to get to its Green Flagships program.

Example: An RF Surgical Tool

An example product can help demonstrate how medical device designers might use the suggestions in this article. A product system includes a disposable and an energy-supplying console. The following section explores the effects of changing these system elements, which are typical to many medical products.

In evaluating the environmental effect of the various components that make up the whole product, designers will need to use real impact data. Various data sources use different units that cannot be comingled. The LCA software makes finding such data easier. It is probably the best long-term solution as a tool for companies, but does require a commitment of money and training that might slow initial efforts. The Okala Guide is inexpensive ($12) and has a useful table of impact factors that covers common materials and processes. It is used in this example. The Okala guide combined with a simple spreadsheet may be good tools to get the development team started.

To make this example easy to understand and illustrative of the kind of improvements possible, not every material or process is considered for comparison. In some places system elements are combined and given overall numbers to ease the reading of the tables.

The analysis focuses on areas where manufacturers can have the most influence and compares the effects of changing those particular parameters. In practice, when you consider the whole product, the actual impact reduction achieved might be a lower than the numbers shown here. However, on an established product an overall 20–30% reduction is relatively easy to achieve.

Product Description. A hypothetical existing RF tool for clamping and cauterizing surgical wounds is being considered for redesign. The company hopes to improve sustainability. The product is a system consisting of a disposable handpiece and an RF energy generator and controller:

The Disposable Handpiece: Consists of a plastic and metal handle with integrated mechanisms that provide mechanical advantage to the surgeon's grip during the procedure, and a wiring harness to connect to the console. The handle is currently single-use (all parts) and contained in sterile packaging. It is manufactured at one location but used in all major global markets.

RF Energy Generator and Controller: Consists of a piece of capital equipment that is a power and control source for the disposable. It is based on 5-year-old electronics and display technology, has no field upgradable features, and is intended to last 5 years in use. The console is built into its own hospital cart.

Two levels of sustainability improvement are considered: first, a few options for redesign of the disposable, and second, a redesign of the reusable energy-generating console. To begin, readers should understand the existing product's ecological footprint to accurately compare new design approaches.

Calculating the Footprint

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Everything that is used to make, use, or dispose of a product, (including materials, processes, shipping, use of energy, etc.) is scored based on its environmental effect. This is calculated using a rating called impact factor. Impact factor numbers have been gathered or researched and reduced to a standardized unit by an agency such as the makers of LCA software or compiled in resources like the Okala guide used here. This factor is based on how the particular parameter is used in the product (e.g., per pound of material, KW-hr of energy, Ton-miles of transportation, etc.) In Tables I, II, III, and IV the total effect of product aspect equals the “Amount” (in whatever units are shown) multiplied by the impact factor. Totaling the scores yields an overall product rating. In this example, units are in Okala milli¬points. Impact factor units must be the same for all contributors. Note that values from sources that do not share units cannot be mingled.

Table I. (click to enlarge) The environmental footprint of a hypothetical RF surgical tool.

The RF device example looks at the effect for the entire life of the product, which is assumed to be five years. (see Table I) During this time a typical user buys one console and uses ten disposables per week, yielding a use of 2,600 disposable per console lifetime. This means that of the roughly 212,000 impact points total shown in Table I, the 2600 disposables used over the product life contribute about 196,000 points. Disposables make a significant contribution to the overall impact, and it is important for designers to consider the overall system usage, not just individual parts, in evaluating and comparing the various redesign choices.

With this calculation in mind, consider the following possible changes to the hypothetical product.

Scenario 1—Make the Disposable Part Weigh Less (console unaffected). This scenario simply considers taking advantage of improved design optimization tools such as finite element analysis (FEA) to reduce the material needed for both the plastic and metal components (without compromising function.)

A slight weight reduction has various virtuous affects. Less material is used, which reduces environmental impact. In addition, lower material cost helps offset the increased design and validation costs of a lighter handpiece. Packaging can also get a little lighter to reduce shipping cost and impact.

Table II. (click to enlarge) In scenario 1, the disposable is redesigned to be made from a lighter material. The result is a 6% decrease in impact over the life of the product.

A modest change to the product like this, requiring no major changes to the way it is made or used, yields a small but meaningful 6% reduction in impact over the product's life (see Table II).

Scenario 2—Make Disposable Weigh Less and Enable the Wiring Harness to be Reusable 20 Times. The development team notices that almost half of the disposable's impact comes from the copper wiring in the leads that connect it to the console. In this scenario, the leads are redesigned to be sterilized and used 20 times instead of just once. The copper content remains the same, but the insulation needs to be beefed up to make the parts rugged enough to withstand re-use. Also, now they will not be packed with every disposable but instead shipped one set per box of twenty handpieces. The product and packaging are overall lighter, further reducing impact. A factor must be added for the sterilization by the hospital.

Table III. (click to enlarge) In scenario 2, the redesign continues. The disposable is made from a light weight material and designers have reworked the wiring harness leads so that they can be sterilized and used up to 20 times.

Reusing the wiring harness has a very significant affect. Now the impact is reduced 44% overall from the reference existing product (see Table III). This redesign does, however, require a change in how the product is sold (box of twenty handpieces with just one wiring harness enclosed) and in how it fits into the hospital's overall workflow. Hospitals must sterilize, manage, and inventory a wiring harness for twenty uses. But copper is also expensive, so now the cost to provide the function of twenty handpieces has decreased. Such savings could be passed on to users in exchange for the task of sterilization, without negatively affecting the manufacturer's profit per handpiece. It is a balancing act, because the cost of sterilizing at the hospital may outweigh any savings.

Although the market may not yet be ready to make such a change in how it handles wiring harnesses, the example does show what an enormous contribution such change can make to how green the system is overall. As some large hospital groups become serious about being more sustainable they may be prepared to make these kinds of changes in the near future.

Table IV (click to enlarge) Scenario 3 builds on previous revisions. It explores how redesigned electronics and a lighter material for the enclosure affect the product.

Scenario 3—Build on Scenario 2 by Redesigning Electronics and Choosing Lighter Materials for the Enclosure. Now the development team turns its attention to the console, and notices that the energy used while the machine is on (usually for a 4-hour procedure) affects every disposable. Modern electronics will not only be RoHS compliant, but also offer a more efficient package in terms of PCB size. Furthermore, new electronics consume half the energy of older electronics (due to improved sleep modes between uses during the procedure). Now that the console is smaller, it can be built into a lighter portable enclosure, rather than integrated it into a heavy cart. Such changes have a significant affect on both disposable and capital system elements, and yield an overall 52% reduction (see Table IV). Notice that if further changes are made to the console electronics to reduce copper wiring by 20–50% (perhaps by some novel pulsing technique or a change in the frequency of the RF), it would have significance to the product's impact score.

A simple spreadsheet scenario like the tables allows a team to see possibilities for redesign. This is obviously a highly generalized example. Only your technical and marketing teams know where opportunities lie for your specific product in its clinical efficacy and marketing acceptability.

The Disposable Matters More

Tables II, III, and IV show the differences between lowering the impact of the disposable and that of the reusable (console) portion. In this example, it is assumed 10 disposables are used per week per console, not an unreasonable assumption for this kind of surgical tool. As noted, this means that over a 5-year design life, 2,600 disposables are used. Therefore even a small improvement in the disposable has a magnified effect. By contrast, if the design team halves the impact of the console it hardly reduces the overall system's impact. For this reason, medical products are often significantly different from consumer products. Using less plastic in a radio will lower its overall impact. Doing so in our medical console example does not have the same results; designers must consider the effect of the whole system's use.

Although the case study shows that focusing the redesign effort on the disposable has the most affect on environment, there are still things the manufacturer can do to the reusable portion of the product that can further reduce the impact every time a disposable is used. In the example, 50% more-efficient electronics in the RF energy generator lowered the energy portion of the product's impact 2,600 times because each use of the disposable cost 50% less energy.

Other medical products can see such savings, too. For instance, a sophisticated mechanism might be used in an electrically-actuated disposable to install an implant in a difficult location in the body. The whole mechanism might be disposable. An appropriate redesign might be one that alters the point where the system breaks between the console and the disposable, moving as much of the mechanism as possible into the reusable portion. A lighter, disposable dramatically reduces the overall systems effect, but makes the console more complex. It might require some innovation to make the coupling functional and convenient for users. A design that moves the coupling outside the sterile field avoids the need to sterilize with every use. Innovation in this area may have a positive business effect for everyone involved. The disposable costs less to make, and can lead to cost savings for the user without necessarily reducing the manufacturer's revenue per procedure. The product can be legitimately marketed as cheaper and greener.

It's Debatable, and That's the Point

Readers will note that it is likely to be hotly debated within a development team whether the kinds of assumptions stated in this article are true, and whether the design goals desired can actually be achieved. In the hypothetical example, a significant portion of the impact reduction on the disposable comes from reusing the wiring 20 times, instead of disposing it after one use. But OEMs are right to question whether the change is reasonable.

Will the surgical team accept this change in their workflow? Will the hospital administration mind having to sterilize and inventory a wiring harness for twenty uses? Will a lighter console be well received in the market if customers are used to having it built into a cart?

Such investigation is critical to understanding the product's lifecycle, imagining changes, and using spreadsheets or LCA software to analyze these scenarios. Some ideas will not work for customers; some will create cost or schedule burden for the manufacturer. Airing these issues allows the development team to have a healthy debate as they choose the best way forward. Perhaps only part of the potential savings should be added to a next-generation product, saving more for the future when all the stakeholders are more comfortable with the changes.

This exercise shows how changes like lowering energy use through a better sleep mode for the console can have a greener consequence than things like using a lighter plastic on the enclosure. It's not always the obvious things that can have the most beneficial effect, and unfortunately finding the changes that have the greatest potential are not formulaic. Each product will have very different aspects that must be rethought. The product's whole life cycle matters, not just early stages like materials or manufacturing choices.

Perhaps as an industry we need to reconsider what it means to be “green.” As Wendy Jedlicka, a sustainable packaging expert, puts it, “The idea that you have to wholly embrace eco like a religion is short-sighted and frankly not sustainable. We need to get everybody doing a little bit of something to mitigate what we are doing right now; then we can keep improving.”

Bill Evans is founder and president of Bridge Design Inc. (San Francisco). He can be reached at bill@bridgedesign.com.

References

1. Philips Medical Green Flagships [online] (Amsterdam [cited 28 May, 2008]); available from Internet: www.medical.philips.com/main/company/sustainability/green_flagships.

Copyright ©2008 Medical Device & Diagnostic Industry

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