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Spotlight on Flow-Control Components

Miniature full-ceramic bearings
An extended line of full-ceramic bearings is suitable for medical device flow-control applications. Balls made from ceramic silicon nitride exhibit greater hardness than steel balls, according to the manufacturer. They also have smoother surface properties than steel balls, resulting in less friction between the balls and bearing-race surfaces. While electromagnetic forces can cause frosting or fluting in the inner and outer races of antifriction chrome-steel bearings, ceramic hybrid bearings eliminate scarring and also run cooler because of reduced microweld adhesion. Available in sizes down to 3 mm, as well as in flanged sizes, the lightweight LBT Mini bearings operate at high speeds in harsh environments in which high temperatures and corrosive substances are present.
Boca Bearing
Delray Beach, FL
www.bocabearings.com

Insertion-style electromagnetic flow sensor
Used for batching, measuring incoming water, and monitoring chemicals or waste effluents in a variety of medical applications, an insertion-style electromagnetic flow sensor features built-in display, empty pipe detection, and bidirectional flow capabilities. Available with PVDF and Hastelloy C wetted parts, the 2551 Magmeter does not have moving parts to wear or foul. In addition, the all-in-one device allows local measurement readings, reducing the number of separate components required at the sensing point. Its display indicates flow rate, permanent flow total, and resettable flow total in a 2 × 16-character dot-matrix LCD format. For further flexibility, the unit can be ordered with optional mechanical single-pole, double-throw, or solid-state relays for alarm indication or control of valves or pumps. Its frequency output is bidirectional, while the 4- to 20-mA output can be set for single or bidirectional flow.
GF Piping Systems
Tustin, CA
www.gfpiping.com

Elastomeric flow-control valve
Developed to ensure dimensional accuracy and close tolerances in medical applications requiring effective bidirectional or one-way flow control, an elastomeric flow-control valve features medical-grade silicones and elastomers. Suitable for use in wound-management, respiratory-therapy, drug-delivery, IV-therapy, and other medical applications, the MediFlo valve can withstand EtO, E-beam, gamma, and autoclave sterilization processes. The valve is designed to replace normally open duckbill valves, which provide low flow rates and poor checking and cutoff capabilities in low-pressure applications, according to the manufacturer. Normally closed, this flow-control valve opens only when a desired pressure is reached. Featuring a rolling sleeve and head, it treats opening pressure, closing pressure, and flow rate as independent variables, enabling the design of custom models.
Liquid Molding Systems Inc.
Midland, MI
www.siliconelms.com

Miniature liquid diaphragm pumps
Available in a compact envelope and featuring an operating lifetime of more than 10,000 hours, miniature liquid diaphragm pumps are based on brushless motor technology. The Hargraves LTC-series miniature diaphragm pumps have Fluid-Blok sealing technology and a monolithic diaphragm design, which can eliminate leaks and allow for maximum suction and priming even under dry conditions. An advanced flow path and efficient valve system maximize flow while consuming low amounts of power as well. Suitable for use in medical applications, the pump can be made from a range of wetted materials, including Teflon, Viton, EPDM, perfluoroelastomers, and chemically inert LCP.
Parker Precision Fluidics Div.
Hollis, NH
www.parker.com

Rotary valves
Rotary valves can be used either in flow-control applications or on syringe pumps. Manufactured in a proprietary manufacturing process using such standard polymers as PCTFE, PTFE, PEEK, and UHMWPE, the rotary valves do not seize up when exposed to crystallizing reagents. In addition, when they are coupled with the company's PTFE or UHMWPE seal technology, the valves provide zero dead volume, which provides accuracy, precision, and longevity.
TriContinent
Grass Valley, CA
www.tricontinent.com
 

Spotlight on Printing, Labeling, and Marking

Track-and-trace technology
Used on pouches and packages, a supplier's track-and-trace technology can be employed to print 2-D bar codes, custom codes, and other mass-serialization codes for authenticating products and tracking them through the supply chain. Offered by an FDA-registered and CGMP-compliant medical device manufacturer, the technology can be layered with overt and covert security features and tamper-indicating void patterns for extra protection. Capabilities include island placement for transdermal and placebo patches, multiple-panel booklet labels, extended-content labels, laminating, custom die-cutting, printing, kit assembly, and cold-seal packaging.
ATL
Menomonee Falls, WI
www.atlco.com


Heat-shrink-tube, bar code, and adhesive-label printer
Designed for medical device manufacturing operations, a system can be used to print color-coded labels, bar codes, heat-shrink tubes, and wire-wrap identification labels. The BEE3+ accommodates a greater variety of heat-shrink-tube widths than the original model, including all 11 LabelShop heat-shrink-tube sizes and colors and a new wide-format ½-in. size. The printer kit includes a printer with a rubber edge guard, a dc auto or ac adapter, a ½-in. heat-shrink-tube cartridge, a ½-in. tape cartridge, a wrist strap, and six AA batteries. The system can print six bar code formats and approximately 1000 symbols, including ASNI, safety, biohazard, and other symbols.
K-Sun Corp.
Somerset, WI
www.ksun.com

Label applicator
A label applicator with a high-speed servomotor drive can outperform stepper and clutch/brake applicators in speed, accuracy, and dependability, according to its manufacturer. Capable of attaining speeds of up to 1500 linear in./min and, depending on the label and product size, approximately 250 labels per minute, the #1510 applicator offers a range of features. Among them are automatic setup capability, user-friendly operating software, a heavy-duty industrial design, 25 I/O points that enable easy integration with other machines, two serial ports, a missing-label detector, and a touch screen user interface. The applicator is also available in right- and left-hand models and can easily be supported and serviced in the field. Labels can be applied using tamp, wipe-on, flag, blow, corner-wrap, or swing-tamp methods.
Label Mill/Coding Solutions Inc.
St. Charles, IL
www.labelmill.com


Laser marking and engraving
Featuring pulse frequencies of several-hundred Hertz and wavelengths as short as 193 nm, a manufacturer's excimer lasers perform cold marking and cold engraving processes on plastic, glass, ceramic, and quartz. As a cold technology, the lasers provide nonthermal interaction and ablative removal characteristics at the short ultraviolet wavelength. As a result, most types of precision marks with feature resolutions on the order of a few microns can be produced on any class of optically transparent materials, according to the manufacturer.
Coherent Inc.
Santa Clara, CA
www.coherent.com


Fiber laser coders
Compact and fast, a company's fiber laser coders are suitable for such applications as direct parts marking and unique identification coding on a variety of metal, plastic, and hard-to-mark medical devices. Providing 10 and 20 W of output power and speeds of up to 350 and 700 characters per second, respectively, the Videojet 7210 and 7310 fiber laser coders feature a small marking head and straight-out or 90° beam options. They feature quick setup capability, easy integration into complex production lines, remote application diagnostics and controls that do not require a PC, and an air-cooled optical fiber as the laser medium. In addition, both coders can apply complex variable data, such as high-quality identification matrix codes, bar codes, logos, and serial numbers, on moving and static products. They also do not require the use of consumables such as inks, solvents, or compressed air.
Videojet Technologies Inc.
Wood Dale, IL
www.videojet.com


Label-processing system
A label-processing system
is designed for the automatic application of labels to bags, flats, and pouches with or without zippers. The compact Labelmaster printer and applicator can meet the demands of medical device packagers. It is PC controlled and is compatible with most off-the-shelf label software programs. The system can apply blank or partially preprinted labels with a maximum size of 6 × 10 in., with or without die-cut inserts, to pouches with a maximum size of 17 × 17 in. Minimal size changeovers and operator training are required.
About Packaging Robotics Inc.
Thornton, CO
www.aboutpackagingrobotics.com


Laser marking systems
A manufacturer offers computer-controlled, noncontact material-modification laser systems ranging in size from small-footprint, self-contained units for low- to medium-volume production runs to extended-size machines for medium- to high-volume production runs. Designed for product development, all of the company's systems can process a range of materials. Using patented high-power-density focusing optics, the laser systems can directly mark metals such as stainless steel, chrome steel, and titanium without the need for metal-marking compounds. Their cells can permanently mark medical components, surgical instruments, and engineered plastics. They can be used to make labels, identification tags, bar codes, 2-D data-matrix codes, and nameplates, in addition to pad-printing plates, prototypes, 2-D buildups, and 3-D textures.
Universal Laser Systems Inc.
Scottsdale, AZ
www.ulsindustrial.com

Vision Technical Keeps Its Eyes on the Mold

Vision Technical specializes in laparoscopic stapling device components, dosage-metering devices, and other medical device applications.

Since day one, Vision Technical Molding (Manchester, CT) has been committed to complex medical molding applications. Founded in 1996, the supplier supports medical device OEMs with product design, tooling and molding, assembly operations, product testing, and project management. To that end, it provides components for medical and surgical equipment, diagnostic devices, and other medical applications. Well into its second decade, the supplier prides itself in furnishing high-precision molded plastic parts fabricated under closely monitored conditions.

"From the start, Vision built an immediate foundation in the medical device industry," remarks Steve Arnold, the company's president. The firm was created to support sister company and strategic partner Advance Mold & Manufacturing (Manchester, CT), an injection mold supplier that was formed more than 50 years ago. "Making this commitment early on to medical device manufacturing has enabled us to develop robust documentation and quality systems," Arnold adds.

With three Class 100,000 cleanrooms, the ISO 9001:2008- and ISO 13485:2003-certified company offers full-service molding solutions to medical device customers. Its molding machines range from 28 to 330 tn, supporting a spectrum of materials ranging from commodity resins to high-temperature, filled engineering thermoplastics.

"Enjoying the support of our sister company, we offer complete mold design and build services," Arnold mentions. "By drawing on Advance's assistance in conjunction with our own tool room, we can provide tooling support from concept through the life of the product." Accustomed to making tools that can fabricate molded parts with tolerances down to 0.0001 in., the firm's toolmakers can produce molds for high-cavitation, multiple-action, hot-runner, and tight-tolerance applications.

Over the years, Vision has expanded three times as a result of customer needs. "The company started out with four molding machines and now boasts nearly 30 presses in a facility that was built from the ground up," Arnold explains. "The needs of cleanroom molding were taken into consideration at every step."

Such expansions are going to good use, enabling Vision to fabricate components with complex geometries. "One of our OEM customers has its own molding operations but comes to us for difficult-to-mold products such as high-tolerance parts," Arnold says. Thus, when it fills orders for laparoscopic stapling device components, dosage-metering devices, delivery devices, lens-replacement surgery parts, and implantable joint components, the company has 20/20 vision.

Vision Technical Molding
www.visionmolding.com

Booth #1043

Service Provider Focuses on OEMs’ Optics Needs

Reflective couplers from LightWorks Optics are part of an illumination system for a laser-based surgical tool.

From gastrointestinal endoscopes and arthroscopic devices to x-ray scanning machines and surgical robots, many medical devices require optical systems and assemblies. Recognizing that advanced optical technologies represent the wave of the present and the future, LightWorks Optics (Tustin, CA) concentrates on offering integrated optical systems for a range of applications--including in the medical device arena.

Founded in 1997 by Daniel Barber, Roger Johnston, and Donald Small--optical engineers with more than 50 years of combined experience--the company decided to focus on optics products and services to solve the design and manufacturing needs of customers in the aerospace, defense, commercial, and biomedical sectors. "We offer high-precision designs for optics components and systems, including visible, infrared, and laser-based optical systems and subassemblies," explains Lisa Belodoff, LightWorks Optics's director of marketing. "We do it all in a high-volume production facility equipped with environmentally controlled cleanrooms certified to ISO 9001:2008 standards."

Offering precision components and optics systems as well as testing and manufacturing capabilities, the company provides a range of services, Belodoff says. "We specialize in engineering and analysis, mechanical design and engineering, and thermal and structural analysis, while also providing manufacturing engineering, and assembly and integration." At the same time, the service provider offers consulting services at the project requirements definition phase; conceptual and detailed design services at the engineering phase; and manufacturing, engineering, and fabrication expertise at the prototype and production phase.

With expertise in those areas, LightWorks Optics turned to the medical device sector. "Several years ago, we realized that many new products being developed in the life sciences sector require sophisticated optics components, systems, and assemblies," Belodoff comments. "Since many medical device companies have little or no optical design and engineering expertise, we provide our customers with a specialized avenue for closing this design, assembly, testing, and manufacturing gap." The company's offerings fit anywhere that complex optical systems are needed, Belodoff adds, including in such target areas as monitoring sensors; clinical, laboratory, and point-of-care diagnostics; and lasers, ophthalmoscopes, and ophthalmic surgical microscopes.

 "Our production facility, including its cleanroom and diamond turning capabilities, are well suited to some of the specialty manufacturing needs of our medical device customers," Belodoff says. "But to date, that has not been well publicized." Determined to turn things around, the company insists that getting out the word will be an important focus of its future activities. "In addition," she adds, "we will continue to build awareness about how our engineering design and manufacturing engineering skills can be used to make complex optics systems and assemblies."

LightWorks Optics
www.lwoptics.com

Booth #2463

Digital X-Ray Manufacturer Passes Inspection

The Xpert 80 digital x-ray system can be used to detect dangerous defects in medical devices.

Kubtec (Milford, CT), as its motto declares, is committed to going beyond the surface. And with its digital x-ray inspection systems, the company has helped customers to do the same in applications ranging from enforcing safety with the Department of Homeland Security to imaging excised breast tissue for cancer diagnosis and detecting minute defects in life-saving medical devices.

As an exhibitor at the MD&M East Quality Pavilion this year, the company will be focusing on forging new OEM partnerships centered on its product line's use in medical device quality assurance applications. In this capacity, its compact, digital systems serve to identify deformities, missing components, and cracks that may be invisible to the naked eye. If not caught, such mistakes could cause device failure in the field.

"The whole concept of x-ray is that it picks up differences in material density, whether that difference is a void, an air bubble, an air pocket, or a crack in any material: metal, plastic, aluminum, iron, or steel," explains Vikram Butani, company president. "You just need varying levels of x-ray intensity to penetrate them, and then the image shows up in various shades of gray on the monitor."

Digital x-ray inspection and nondestructive testing of various medical devices and components is safe and simple, Butani adds, because Kubtec designs its automated systems with compact form factors and user-friendly controls that do not require specialized training. In addition, the FDA-approved x-ray units are self-contained enclosures, which is a construction that safeguards operators and other workers from radiation exposure.

Equipped with an x-ray source of up to 90 kV, the Xpert 80 system is among the company's offerings suited for use in medical device quality control. It also boasts high-resolution imaging capability. "We can do images that go down to a few microns--very small changes in density that are finer than a human hair can be picked up with our system," Butani remarks. Upon capturing an image, the system's image-analysis software allows users to enhance geometric magnification by up to five times for closer inspection.

For OEMs that do not need or want to integrate inspection capabilities in-house, Kubtec offers lab services. Customers can ship samples to Kubtec for imaging and analysis. "We can take some images and present them to them online in real time as they're being imaged by our systems," Butani states. "You save time, money, and you get quick feedback without having to take an entire entourage of engineers to our facility or to ship an entire machine."


Kubtec
www.kubtec.com

Booth #1781

French Scientists Create World's First Glucose Biofuel Cell

Glucose naturally found in the bloodstream could be used as an energy source for implantable medical devices.

Researchers in France have announced the development of the first functional glucose biofuel cell. Potential applications of the research include biosensors, drug-delivery devices, insulin pumps, neural and bone-growth stimulators, and synthetic organs.

Led by Philippe Cinquin, a team of scientists at Joseph Fourier University (Grenoble, France) confined selected enzymes inside graphite disks placed in dialysis bags in a study on rodents. The device generated electricity as glucose and oxygen flowed into it, triggering enzymes to catalyse oxidation of the simple sugar. The maximum power generated by the biofuel cell in the experiment was 6.5 µW. In the research, the device produced power for three months. Such a device could theoretically produce power for the rest of a patient's life.

While other researchers have attempted to use glucose to generate electricity, the enzymes they used were not suitable for implants because they were inhibited by ions found in the body or required highly acidic conditions. In contrast, the new technology is not limited by these constraints.

More information on the research is available from Scientific American and Technology Review.

Polymer Manufacturer Holds Up Under Pressure

Akton viscoelastic polymer, manufactured by Action Products, provides pressure reduction properties, as well as shock absorption and vibration damping for medical applications.

Basement chemistry experiments are often a recipe for disaster. But in the case of Dr. W.R. McElroy, they actually yielded a unique, ultrasoft viscoelastic polymer that became the foundation of a successful business.

Founded by McElroy in 1970, Action Products (Hagerstown, MD) put the synthetic polymer, dubbed Akton, to use in the development of wheelchair cushions and bed pads, and eventually expanded into the fabrication of pressure-relieving products for the operating room. "We made a lot of positioners for the operating room table and the pads that go on the operating room table itself," says Michael Bredal, vice president of business development. "Through clinical studies done independently by OR nurses, we were able to show how effective our pads were at preventing pressure ulcers compared with regular foam mattresses, and that was really our breakthrough."

Vertical pressure and shear forces, friction, temperature, moisture, and other factors can contribute to the development of pressure ulcers, or bedsores as they are commonly known, in immobile patients. Although typically preventable, pressure ulcers can be hard to treat and even fatal if they develop. Action Products's Akton polymer-based pressure-relieving pads and positioners are designed to minimize the opportunity for these ulcers. "Shear forces have been reduced by making the surface movable," Bredal notes. "When the body moves, the material moves, versus foam, which gives you some resistance." He adds that the Akton polymer absorbs heat almost at the same rate that the body produces it and is also more durable than foam.

Although the company makes its own end-use products from the Akton polymer, it can also provide the material to medical device OEMs. And the versatile, synthetic rubber also features desirable properties beyond pressure reduction, according to Bredal. For example, having proven successful in a sleep apnea mask and as a protective, tissue-equivalent phantom material for radiation therapy, the polymer has potential for use in a variety of medical products. Properties and characteristics of the nonconductive material include shock absorption, vibration damping, softness, durability, heat reduction, pliability, and shape retention.

To accommodate OEM partners, Action Products maintains engineering and R&D departments and has 3-D CAD modeling, SLA and CNC machining, moldmaking, and lean manufacturing capabilities. "We know that there are other applications out there," Bredal states, "and we enjoy working with other companies to realize the applications they are working on."

Action Products
www.akton.com

Booth #646

Debrider Has a Nose for Bacteria

Some 30 million adults in the United States suffer from chronic sinus infections or sinusitis, the initial causes of which are usually bacteria or anatomical problems. While functional endoscopic sinus surgery (FESS) is often used to remove bacteria and correct anatomical obstructions, from 10 to 25% of these surgeries do not cure patients of the recurrent disease because bacteria can be difficult to remove from sinus cavities.

With its handheld Hydrodebrider endoscopic suction irrigator system, Medtronic ENT (Jacksonville, FL) aims to provide surgeons with a power-washing instrument that directly irrigates all surfaces of the paranasal sinuses with pressurized saline to remove bacteria. "Due to the unique anatomical structure of the sinuses, this is no simple feat," says Bryan Jones, associate product manager at Medtronic ENT. "The sinuses tend to be very narrow, and surgeons must make 'U-turns' during endoscopic surgery to reach all the relevant anatomy."

Undeterred by morphological roadblocks, the Hydrodebrider features a pump that supplies pressurized saline at 4 to 6 ml/sec through a tip that produces a fan-shaped spray. This spray can be rotated using a thumb wheel, enabling the surgeon to achieve a spread of 360°. In addition, the distal tip can be articulated up to 270°, enabling the surgeon to spray difficult-to-reach anatomical features such as the medial wall and floor of the maxillary sinus. "A common analogy would be a device that enables you to reach around a wall and power wash the dirt sticking to the other side of it," Jones says.

To develop the irrigation device, Medtronic ENT partnered with Metaphase Design Group (St. Louis), which identified clinicians' usability needs and established an industrial design language that was consistent with the brand architecture Metaphase had established for the design of other Medtronic ENT products.

"Initially, we developed conceptual designs for the Hydrodebrider using Medtronic's engineering CAD files as underlays," remarks Bryce Rutter, founder and CEO of Metaphase. "From this conceptual exploration, the Medtronic-Metaphase team down-selected to a 'best' final design direction and continued codevelopment to ensure that engineering, ergonomic, and industrial design elements were optimized for the overall outcome of the product." Throughout this development process, the two companies used several stereolithography rapid models for real-time testing and evaluation.

"Sinus surgeons have significant ergonomic issues," Jones comments. "They hold an endoscope in one hand while manipulating instrumentation in the other, all while working within the confines of one or two small nostrils. Unfortunately, ergonomic design is not a primary focus of many companies that create products for these surgeons." In contrast, Metaphase's team includes experts in hand function, kinesiology, cognitive and physical ergonomics, physical therapy, human behavior, and industrial design--a crucial skill set for developing such ENT devices as the Hydrodebrider.

Metaphase brought this skill set to bear in addressing a host of ergonomic and design challenges. "Critically important to the success of this handpiece was developing controls that were obvious, explicit in functionality, and intuitive," Rutter says. "Our hand and ergonomics experts designed controls that cognitively map the functionality of the design element being controlled." Designers also considered the hand-size differences between men and women. "The difference between a small fifth-percentile female hand and a large 95th-percentile male hand can be as much as 2 inches in length and 1.25 inches in width," Rutter explains. "We designed the handpiece grip topology to accommodate this variability without sacrificing comfort and precision for both male and female sinus surgeons."

Medtronic has worked closely with Metaphase on several previous projects, Jones notes. "Considering how difficult it is to control spray power, rotation, and tip articulation all with one hand, hearing surgeons say that the system 'feels right' indicates that Metaphase has done its job."

Vein-Illumination Device Helps Clinicians Stick it the First Time

Providing a blood sample is an activity enjoyed by few patients. Luckily, clinicians are well-versed in venipuncture, and it can be a relatively quick and painless process. Unless a patient has "difficult" or hard-to-detect veins, that is, in which case, the uncomfortable poking and prodding begins.

To minimize opportunities for multiple needle sticks during venipuncture--and thereby improving patient care and efficiency--AccuVein LLC (Cold Spring Harbor, NY) developed the AV300 portable, noncontact, vein-illumination device. "The AccuVein AV300 highlights the hemoglobin in the veins differently than the surrounding tissue, so it helps identify veins for all venipuncture procedures from IV starts to blood draw," says Heidi Siegel, director of marketing communications for AccuVein. "It's really the first vein-illumination device in the industry that is portable and noncontact." The user simply positions the device seven to 10 inches above the targeted area. Employing red and infrared light, the product then shows a real-time projection of the patient's veins on the surface of the skin for clear vein targeting.

Although the device is engineered to be user friendly and simplistic, achieving that final product was not quite so easy. Armed initially with a rudimentary proof-of-concept, AccuVein sought a partner that could help take the proprietary system from concept to commercialization. It found one in electronics manufacturing service provider Benchmark Electronics Inc. (Rochester, MN). "The biggest challenges were to take the proof-of-concept and make a repeatable design that we could mass produce," recalls Daniel Dion, senior industrial designer at Benchmark. "We had to create boards and a digital system from [a design] that was previously analog."

Working together, the two companies focused on optimizing the form factor to promote usability and portability--two characteristics that were identified as potential differentiators in the market. Competing vein-finding products were either essentially low-tech flashlights lacking advanced functionality or heavy, refrigerator-sized equipment that could not be moved to the point of care, according to Siegel. With the 10-oz AV300, however, the companies aimed to produce a high-tech device in a compact package capable of being transported in a clinician's pocket.

Human factors testing, extensive industrial design work, and multiple engineering cycles contributed to determining the final design. "Anybody picking it up had to know how to hold the product in their hand, so we went through several form studies to determine what the correct form factor for this product is," Dion notes. "It is crucial that it is held properly for the product to work properly, so we had to find out the right way to hold it. Where we positioned the controls on the product was critical to telling a user who has never seen it before how to pick it up and use it. Through the form development, we were able to do that."

The device's small, lightweight form factor presented multiple challenges throughout the course of the product development cycle, especially in terms of maximizing space and functionality in a small package. Furthermore, the engineers were faced with solving the thermal conundrum of how to cool the heat-generating product without the use of a fan. "We developed a decorative heat sink that goes all the way around [the AV300], which makes the product look great but also has a high functional value," Dion says. "That's how we get the heat out of the device; it's the actual heat conductor that acts as the heat sink for the product."

Benchmark also designed all of the boards and the software in addition to providing software integration and making such complex parts as the optoelectrical engine that serves as the driving force behind the product's complex functionality. "I think it is truly the first portable, noncontact, vein-finding device that has been developed," Dion says. "There have been others that have been fairly crude, but with this one, the efficacy of allowing you to find the vein has increased so much because of the technology behind it."

The Age-Old Stethoscope Goes High-Tech

Everyone is familiar with the stethoscope--the archetypal medical gizmo that doctors drape around their necks and hold against patients' chests on countless TV shows, not to mention in real life. But that old workhorse of medical professionals everywhere has gotten a modern makeover--it's gone digital.

An electronic device used to listen to patients' body sounds for diagnostic support, the Littmann Model 3200 stethoscope from 3M (St. Paul, MN) is unlike the stethoscopes of old. Featuring on-board recording capability, the instrument enables clinicians to record sounds for peer review or teaching purposes. It works in conjunction with StethAssist heart and lung sound-visualization software from Zargis Medical (Stamford, CT) and the Zargis Cardioscan cardiac diagnostic support software, which communicates with a PC via a Bluetooth wireless channel. By playing back original sounds recorded by the stethoscope or replicating them through headphones, the PC now allows doctors to listen carefully to their patients' hearts.

"Doctors' ability to perform auscultation--the act of listening to the internal sounds of the body--has been declining in part because of reliance on advanced technology such as echocardiograms," explains Tim Chismar, a technical service engineer at 3M. The new stethoscope aids doctors in performing auscultation to help them differentiate between real and apparent heart anomalies and reduce their reliance on echocardiograms. However, to overcome the inherent difficulty in performing chest auscultation using traditional, nonelectronic stethoscopes, the Littmann device amplifies body sounds of interest and reduces distracting ambient noise.

The auscultation skills acquired by physicians through experience are augmented by the computer-aided technology provided by the Cardioscan software, Chismar says. With the assistance of a voice-guided protocol, this software enables physicians to record heart sounds. It also helps healthcare professionals to establish good clinical practice by directing them to record heart sounds from standard sites on the chest in a fixed, repeatable sequence. In addition, the protocol establishes the connection between individual recordings and their associated location on the chest, retaining information that is essential to clinical diagnosis.

Designed for exclusive use with the Littmann 3200, Cardioscan uses algorithms that detect suspected heart murmurs, remarks John Kallassy, CEO of Zargis. "This software helps differentiate whether a murmur is innocent or pathological and whether or not further testing is needed," he says. "We do that by looking at the characteristics of the murmur."

Heart-sound analysis can be challenging because everyone's heart is different, Kallassy notes. "Hence, analysis algorithms must recognize acoustically different heart sounds as being the same, while distinguishing the first heart sound from the second and murmurs from background noise." Cardioscan achieves this using signal-processing methods that exploit time-frequency analysis and statistical modeling methods.

Featuring a chrome-plated metal housing that reduces ambient noise while minimizing frictional noise created by the user's fingers, the device was designed by Bang & Olufsen Medicom (B&O Medicom; Struer, Denmark). "We designed and built the stethoscope based on inputs from 3M," comments Carsten Pedersen, project manager at B&O Medicom. "That involved industrial design, mechanical and electronic design, and firmware development, including the Bluetooth wireless interface."

Because B&O Medicom developed the first digital electronic stethoscope for 3M in 2001, it was well qualified to meet the challenges involved in making the new model. "One challenge was to minimize the size and weight of the device, which uses a relatively large AA battery to support the Bluetooth communications," Pedersen says. "Another was to install a Bluetooth antenna inside the metal chassis while ensuring the required range of wireless transmission." This capability was achieved by making the antenna an integrated part of the PCB in the chest piece of the stethoscope and shaping it to achieve uniform reception all around the chest piece.

"Nearly every physician today has access to PCs that are powerful enough to run sophisticated algorithms," Kallassy concludes. "It made sense for us to marshal the power of computing to assist the healthcare professional's ears in understanding and making more sense out of physiological sounds."