Electronic Design
Better Medical IC Technology Gets Ready To Make House Calls

Better Medical IC Technology Gets Ready To Make House Calls

Semiconductor IC technology is forming the bedrock of portable and affordable medical equipment, much of it for personal use at home, at a local clinic, or even while traveling. Driving forces include an aging population, longer life spans, and the need to control rising healthcare costs. There’s also a growing need to bring healthcare diagnostics and treatment more quickly to the patient, away from medical centers and closer to the home.

Major electronics companies are eager to cash in on these beckoning market opportunities. According to InMedica, a division of IMS Research, the combined unit shipments of home use digital glucose meters, blood-pressure monitors, weight scales, pulse oximeters, and peak-flow meters for medical diagnostics will exceed 1.5 million units by 2013. InMedica also predicts an increase in the number of health management hubs, bringing the total of telehealth-related devices to more than 2 million units by then.

Intel and GE have formed Care Innovations to develop technologies that support healthy, independent living at home and in senior housing communities. The company combines the assets and the expert teams and operations of both GE Healthcare’s Home Health division and Intel’s Digital Health Group to address the aging population, the growing number of people with chronic conditions, and increasing healthcare costs.

“Our vision is to positively affect millions of people by providing innovative products and services that will enable new models of care,” says Louis Burns, CEO of Care Innovations.

Technologies On Tap

A host of semiconductor ICs is available to facilitate the design and development of portable home healthcare products, including sensors, microcontroller units (MCUs), microprocessors, DSPs, FPGAs, memory chips, and system-on-a-chip (SoC) devices.

Microelectromechanical-systems (MEMS) technology is playing a major role in home healthcare in the form of sensors, microfluidic devices, and actuators, with some market-size estimates for medical healthcare microsystem devices totaling about $4.5 billion by 2015, most of it for in-vitro diagnostics and home healthcare.

It is only a matter of time before high-sensitivity MEMS accelerometers will be used to closely and more accurately monitor and measure drug dispensation into the body. Wireless sensor transceiver manufacturers are also working closely with drug manufacturers to monitor and measure drug deliveries into the body.

SoCs are becoming more powerful and flexible. Cypress Semiconductor offers a programmable SoC (PSoC) comprising configurable analog and digital blocks, a CPU subsystem, and programmable routing and interconnects. A PSoC allows designers to plug in predefined and tested intellectual property (IP) from a PSoC library of functions, or their own code, to develop medical equipment like a pulse oximeter (Fig. 1).

FPGAs have also made it easier and faster to design portable low-power medical appliances. For example, designers can craft insulin pumps with the intelligent mixed-signal SmartFusion series of FPGAs from Microsemi’s Actel.

These off-the-shelf FPGAs are the only devices that integrate an FPGA fabric, an Arm Cortex M-3 microcontroller, and configurable analog circuitry, as well as substantial flash and static RAM (SRAM) memory plus comprehensive clock generation and management circuitry (Fig. 2).

The Analog Devices ADXL322 iMEMS digital accelerometer is used in Zoll Medical’s PocketCPR, a palm-sized cardiopulmonary resuscitation (CPR) device that enables the accurate measurement of the rate and depth of chest compressions administered by rescuers. It coaches people performing CPR with both audio and visual instructions to initiate the critical rescue steps needed for reviving someone from sudden cardiac arrest (SCA) and conforms to recommendations set forth by the American Heart Association.

“Many people are reluctant to perform CPR because they are not trained to do so or lack the confidence to perform this life-saving procedure. PocketCPR gives them the assurance they need to perform CPR in an emergency,” says Mark Totman, president of Bio-Tek Inc., a wholly owned subsidiary of Zoll Medical. PocketCPR is approved by the U.S. Food and Drug Administration (FDA) for over-the-counter sales.

Less Power/More Computing

Home healthcare medical devices often require less power consumption and more computation power. “Low power dissipation is a critical requirement for portable home healthcare products, and we have demonstrated this with our large family of 16-bit and 32-bit MCUs,” says Bobby Wong, MCU marketing manager at Renesas.

“In 2007, we were the first to offer low-power, 100-MHz, 90-nm-node embedded flash memory for minimal power consumption when a processor switches between wakeup and slope modes. We’re working on 120-MHz, 40-nm-node flash memory for even less power dissipation,” adds Mark Rootz, Renesas senior marketing manager for 32-bit MCUs.

Microprocessor chips are forming the core of a wide variety of personal healthcare devices. The Personal Health Card from LifeNexus secures and maintains an individual’s personal health record in a credit-card form factor. Healthcare providers and pharmacists can access its data, maintained by the iChip from STMicroelectronics, via the LifeNexus Health Information Platform, which uses mobile server technology embedded on a chip card that is both encrypted and password protected.

“This is without a doubt a profound, highly secure technology providing a remarkable consumer solution—a healthcare and financial card in one,” notes Marie-France Florentin, general manager for the STMicroelectronics Secure Microcontroller Division. “It delivers a solution that raises the bar on mobility, security, and convenience with healthcare.”

LifeNexus recently offered healthcare providers like pharmacies, physician offices, and hospitals 10,000 professional card readers loaded with the iChip acceptance software free of charge. This will make personal health records as easy and secure to use as payment cards.

MCUs and other devices are powering various methods of drug delivery, one of the more promising areas where electronics technology will have a major impact in healthcare. Manufacturers of MEMS sensors like accelerometers, MCUs, and wireless transceivers are actively working with major pharmaceutical companies on drug delivery methods that are more automated and easier to use, whether they’re via injections, pills, transdermal patches, or inhalers, while yielding faster and more accurate results.

Microchip Technology is examining the role of its PC12F MCU in newer active drug patches that use the iontophoresis principle for operation in which a direct current is applied to increase the drug-molecular diffusion rate through the skin. The MCU works with a boost converter to increase the voltage levels needed for patches powered by lithium coin-cell batteries that often cannot supply high enough voltages for iontophoresis to work properly.

The choice of using either 16-bit or 32-bit MCUs falls largely to the application involved. “There is quite a bit of pre-processing needed for devices like automated external defibrillators (AEDs) at the local data-collection point, which a 32-bit MCU can expedite and speed up the transmission of data to a host processor at lower power-dissipation levels,” explains Mark Rootz of Renesas. “And here you need 32-bit MCUs like our SH7216s, which combine 200 MHz with 400-Dhrystone MIPS processing with a hardware floating-point unit.

Wireless Everywhere

Wireless communications via cell phones is revolutionizing personal healthcare diagnostics, management, and treatments. It’s also driving medical device innovation. Many medical applications have cropped up for smart phones.

Paul Errico, strategic marketing manager at Analog Devices, cautions that “of the thousands of mobile phone applications appearing on the market, it is important that users understand which of these is really cost-effective in bringing down the costs of home healthcare.” He emphasizes that “a few years from now, the winners of those portable healthcare products will be the ones that will provide true clinical value to the market for personal medical devices.”

Bobby Wong of Renesas agrees. “Quality and longevity are key parameters required for successful portable home healthcare medical products. Those companies who can supply this through their many years of experience are in the best position to dominate the market,” he explains.

According to David Niewolny, medical product marketing manager for Freescale Semiconductor’s Microcontroller Solutions Group, wireless connectivity will significantly reduce the cost of managing a chronic disease by decreasing the number of incidents of complications.

Niewolny estimates that the average annual home healthcare expenses for people with a chronic disease is nearly $11,700, which is nearly triple that of people without a chronic condition. For those with chronic conditions as well as complications, costs rise to a staggering $20,700. This is a major driver for wireless connectivity for monitoring cardiac and blood sugar data to improve patient compliance. When physicians can monitor this data remotely, they can improve the patient’s quality of life.

The Continua Health Alliance has so far approved ZigBee, Wi-Fi, Bluetooth, Bluetooth Low Energy (BLE), ANT, Sensium, Z-Wave, and BodyLAN communications protocols for wireless medical data communications. The Alliance has entered into an agreement with the Wi-Fi Alliance to facilitate and promote the adoption of Wi-Fi networking technology in connected health applications.

Fatigue Science is using 2.4-GHz ANT transceivers from ultra-low-power RF specialist Nordic Semiconductor ASA for medical-grade assessment monitoring of sleep quality, quantity, and timing at a fraction of the cost of an overnight stay in a specialist sleep clinic. The ReadiBand, a wristwatch form-factor device, uses a series of sophisticated algorithms to measure sleep data from a user’s wrist movement (known as actigraphy) that is wirelessly downloaded to a computer for analysis via the Nordic ANT transceivers (Fig. 3).

Gentag Inc. has demonstrated a disposable wireless diagnostic test platform for consumer cell phones using near-field communications (NFC). Based on immunoassays, Gentag’s technology lets consumers instantly test for pregnancies, fertility, pathogens, AIDS, drugs, allergens, and even certain types of cancers no matter where they are. NFC is a short-range wireless communications technology that enables the exchange of data between devices over a 10-cm distance.

The three largest wireless carriers in the U.S.—Verizon Wireless, AT&T Mobility, and T-Mobile USA—have endorsed the NFC approach. They formed a joint venture known as ISIS to develop a single NFC platform, and they intend to release software for handsets and payment terminals in select U.S. regions over the next 18 months, with a nationwide rollout planned by 2013.

NuPathe Inc. is on its way to making available what it expects is the first disposable single-use drug patch for use in treating migraine headaches to be available in the U.S. at a reasonable cost to consumers before June of next year. About 31 million suffer from migranes, according to the company.

Having cleared the first regulatory hurdle from the U.S. Food and Drug Administration (FDA), the Zelrix patch uses a proprietary transdermal delivery system called Smart Relief. It employs electric current to generate an ion transfer between the patch and the skin to administer the migraine drug, using a coin-size microprocessor and two coin-size battery cells. Worn on the arm or thigh, the patch provides about four hours of relief (Fig. 4).

Zelrix delivers 6.5 mg of sumatriptan, the most widely prescribed migraine medication, in a highly controlled and predictable manner. It relieves migraine symptoms without exceeding blood levels that are commonly associated with side effects of drugs in this class, like nausea and vomiting.

The core technology in this patch is embedded in its software, which knows the level of current to use to activate the ion-transfer process without irritating the skin. It also knows how to program the drug’s delivery for optimal effect, without any user intervention. The patch is manufactured by a German contractor that specializes in drug patches.

“We see this patch as allowing us to do more things than just migraine drug delivery, a space which we intend to own,” says Jane Hollingsworth, CEO of NuPathe. “We can also use this platform to treat other ailments like Parkinson’s disease and bipolar disorders.”

One of the more notable drug-delivery mechanisms is the Jewel insulin pump from Debiotech, co-developed with STMicroelectronics using the latter’s microfluidic MEMS technology. It is pending FDA approval. The pump can be mounted on a disposable skin patch to provide continuous insulin infusion, enabling substantial improvement in the treatment efficiency and quality of life of diabetic patients.

The FDA is now evaluating a new rapid, affordable, high-sensitivity electronic diagnostic testing system called the CliniHub that is expected to be used in doctors’ offices, other patient care settings, and, eventually, at home. Currently, the CliniHub has assays to screen for breast cancer, methicillin-resistant staphylococcus aureus (MRSA), and heart disease.

Xen Biosciences contracted with Cambridge Consultants to create the compact, modem-sized device, which is expected to sell for less than $100. Using time resolved fluorescence (TRF) spectroscopy, it will process fluid samples deposited on inexpensive, disposable electronic assay cards and then display the findings.

The companies developed testing substances for their digital diagnostic assay card to detect the presence of breast cancer and cardiac biomarkers as well as others that have not yet been publicized. (Xen Biosciences believes it won’t be long before it will have tests for up to 20 ailments.) A fluorescence label is combined with the sensitive detection electronics of TRF spectroscopy to successfully increase the sensitivity of a human chorionic gonadotropin (hCG) pregnancy test by four orders of magnitude.

Xen Biosciences suggests that its TRF point-of-care testing will enable physicians to perform highly sensitive digital spectroscopy in their offices that had only been completed in a clinical laboratory. A consumer version of the CliniHub that’s also under development could be used, for instance, to analyze a throat swab to determine if an inflammation were due to a bacteriological or viral infection so users would know if they should see a physician for an antibiotic.

Bayer HealthCare has launched the FactorTrack, the first customizable and interactive mobile search application for people with hemophilia A (Fig. 5). The free application helps make it easier to track and record hemophilia factor VIII infusions.

FactorTrack captures dosing history, frequency, and locations of bleeds. It allows people with hemophilia A to customize their infusion schedule based on their prescribed regimen, view their infusion history, and, with an Internet connection, display an alert when it’s time for the next infusion. It also gives patients the option of e-mailing infusion and bleed history to themselves or their healthcare team if e-mail is configured on their device. Further, it links people with hemophilia A to educational tools and online resources.

Previously known as T-Ray Science Inc., Verisante Technology Inc. is developing an exciting non-invasive melanoma skin-cancer detection device. The Aura probe has been under development for more than six years with help from the British Columbia Cancer Agency (Fig. 6). It has been tested on 1000 patient lesions at the Skin Care Center at Vancouver General Hospital. Published preliminary clinical results have demonstrated 100% efficacy in detecting malignant melanoma.

Of the 1000 lesions tested, the probe caught every case of melanoma among the 274 patients with the disease. Melanoma is the most common form of cancer and is rapidly increasing in occurrence. Rapid diagnosis is very important since the survival rate is 98% when it is detected early. Patients with advanced skin cancer have only a 15% survival rate.

Aura is based on is Versant’s patented Core platform, which utilizes an endoscopic attachment to aid in early cancer detection. It uses multimodal imaging and spectroscopy to measure 21 bio-markers when scanning a mole or lesion to determine skin cancer in less than 2 seconds by quickly examining skin chemical composition. No biopsies are required. The Core technology is fully extensible to detection systems for lung, colon, cervix, and other cancers.

TAGS: Medical
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