Features

Among medical devices, there is a range of fluid management needs, each with its own unique needs and functions.

The field of fluidics may broadly be divided into macro- and micro-applications. The former encompasses situations where moderate or bulk quantities of material must be moved through an instrument, such as tank filling or waste disposal. The latter applies to applications that require delivery of small, precise quantities. Fluidics, especially macrofluidics, often falls outside of a company’s proprietary expertise in medical device design. Consequently, when an application requires the inclusion of fluid management, OEMs may be best served by engaging an external engineering resource with specialized expertise in this field.

Consolidate and Simplify

Fig. 1 — GEMS Medical Sciences redesigned the manifold of a transport ventilator, reducing its space requirements by 40 percent.
The current trend in medical devices and equipment is towards ever-smaller products. In fact, reducing instrument size or complexity can create new market opportunities. First, a smaller footprint may provide a competitive edge for an OEM. Commercial laboratories, for example, are often measured by revenue per square foot, and will choose to purchase more compact instruments. Second, reducing a device’s size and weight can open new market segments. The smaller the device, the more easily it can be transported for use in non-traditional environments such as disaster zones or field emergency medical services.

In one instance, Gems Medical Sciences was tasked with redesigning the manifold of a transport ventilator, reducing space requirements by 40 percent. Reduction in size and weight can be achieved in numerous ways. One approach is to consolidate components by combining multiple constituent parts into a single functional unit. By incorporating various components, such as a nebulizer and temperature sensor, directly into the manifold block, the team produced a new design that occupied much less space. (See Figure 1)

In some cases, the size of an instrument may be constrained by operational considerations. When this occurs, the answer may lie in automating functions. In the above ventilator case, for example, flow valves in the original design had to be set manually. Access to the flow adjustment on the needle valves limited how small the device could be. To overcome this problem, they re-engineered the manifold design, replacing the adjustable valves with precision orifices pressed directly into the manifold.

Cost Control

Pressure to reduce production costs is particularly strong among medical device manufacturers, for whom the cost of goods is generally very high. Yet OEMs are understandably cautious about adopting cost-based modifications to core technologies that are the foundation of a device’s performance. By driving costs out of non-core systems, such as a fluid handling system, an OEM can preserve cost-flexibility in proprietary technologies.

When considering whether to partner with a fluidics specialist, an OEM must weigh the suitability and short-term cost of employing an outside firm against the potential for improved product performance and for cost and resource savings in the long run. Here are several examples of benefits.

Optimizing Staff Utilization: When even large companies have leaner organizations, working with a fluidics partner can free up valuable staff time. Internal engineers can focus solely on maximizing performance of proprietary components or systems. Small or early-stage companies may find it particularly advantageous to work with an outside fluidics firm. When cash flow is critical, as it is for many start-ups, working with an external partner is often more cost-effective than adding head count. (See Figure 2)

Fig. 2 — External fluidics specialists offer expertise that can help OEMs find innovative solutions to product development challenges.
Shortening Development Time: External fluidics experts, by definition, keep abreast of the latest advances in that technology and can quickly identify design challenges and ways to solve them. In addition, the fluidics component design can proceed in parallel with the design of other system functions.

Streamlining Risk and Data Management: When there is a need for a fluid handling system, an external fluidics partner can deliver a fully assembled unit with a single part number. The subassembly is produced and tested by the contractor, and continuity of test data is maintained back to the component level. Since the contractor is responsible for the complete subassembly, there is a ready source of support if performance issues arise.

Troubleshooting: Beyond original product design, the expertise of an outside fluidics partner can be valuable when an OEM seeks to modify a device already in commercial distribution. This may include situations where a device is not performing to expectations or when a company is seeking to eliminate cost from its manufacturing process.

Early Involvement is Key

The best time to seek fluidics support is early in the development process. Doing so can not only shorten upfront development time, but can also save time — and expense — at the back end of the process, when changes can be expensive to implement. This consideration is especially relevant in the medical device industry, where products and manufacturing are subject to regulatory review and where modifications to a product can require significant testing and validation.

Involving a contract firm early in the development process increases design flexibility and helps ensure that fluidics specifications and solutions will be compatible with overall device performance. In many cases, an OEM will approach a contract fluidics firm with a predefined specification. The contractor then begins its work by developing an in-depth understanding of the assignment and its challenges. This includes reviewing the design specification and clarifying any open questions or concerns. Then, a list of exceptions or concerns can be generated, and fixed and flexible specifications will be explored to create a cost-benefit analysis.

Unfortunately, the findings from fluidics analyses could mandate a revision to the specification or an expensive and time-consuming exploratory pre-development phase, only to discover that the specification must be revised further or, worse yet, is not technically feasible. Furthermore, remedial options later in development may be limited by fixed design parameters.

Involving a design partner early in the creation of the design/product specification will most often prevent these complications. Specifications and solutions are developed early on to be compatible with overall device performance. If necessary, preliminary testing and development can be completed in parallel with the creation of the specification. The result is the release of a more complete design/product specification that has already been validated and accepted by both the OEM and the design partner.

This article was supplied by Gems Medical Sciences, a focused division of Gems Sensors & Controls, Plainville, CT. For more information, visit http://info.hotims.com/40438-189.