Devices such as DSPs and accelerometers make home monitoring devices possible

　　Advanced semiconductor technology is paving the way for smaller and more powerful home medical devices. For patients, the benefits of smaller, portable devices are easier access to care, fewer visits to the hospital, and further reductions in medical costs. To be more effective in a home environment, medical devices must be easy to use, safe (even when used incorrectly), and able to distinguish between correct results and those obtained under incorrect procedures.

　　The rise of home healthcare

　　As more and more baby boomers are aging, the need for home healthcare is becoming more urgent, and the demand for home healthcare equipment is also growing. According to the World Health Organization, the number of people over 60 years old in the world was 650 million in 2006 and is expected to reach 1.2 billion in 2025. In the United States, the proportion of people over 65 years old is higher than ever before, and this number is expected to grow steadily in the 21st century.

　　Examples of home healthcare devices that benefit from semiconductor technology include the 24-hour lung monitor Wholter and the personal asthma assessment device Wheezometer. Both devices were developed by Karmelsonix, an Israel-based company that is a pioneer in the development of medical devices for asthma management. Wholter and Wheezometer meet the urgent needs of the 48 million asthma patients worldwide to self-assess and manage their asthma symptoms that threaten them.

　　Effective asthma assessment (a multivariate lung activity measurement) must be timely and accurate to provide a basis for appropriate medical intervention. In the past, only spirometers in hospitals or clinics had such high reliability, and asthma patients at home or on the road were often at risk.

　　In order to popularize this important patient care tool from the hospital to the home, KarmelSonix uses high-speed Blackfin digital signal processors ( DSP ) and other precision signal processing devices from ADI to ensure that asthma patients can obtain accurate and reliable assessment information of "wheeze rate" (an important dynamic indicator of asthma attacks). Using Wholter and Wheezometer, asthma patients can make early assessments of their symptoms, which is crucial for the subsequent implementation of correct drug treatment.

　　Key semiconductor technologies

　　Many home health support devices have simpler functions but are vital to saving lives and preventing accidents. The PocketCPR produced by Bio-Detek, a wholly owned subsidiary of Zoll Medical, can be placed under the palm of a person's hand to monitor the cardiac resuscitation of a heart attack patient, as shown in Figure 1.

Figure 1. Analog Devices’ ADXL311 accelerometer enables the PocketCPR device

　　The device provides rescuers with audio and visual feedback by measuring the depth of chest compressions, allowing them to adjust to the appropriate depth and correct rate. The product can also guide relatively inexperienced rescuers to build confidence and assist experienced caregivers with appropriate techniques. PocketCPR uses ADI's ADXL311 accelerometer, which can accurately measure the movement of the PocketCPR under the rescuer's palm.

　　FallSaver, shown in Figure 2, is simpler and can be used for patients who cannot walk without help. Whether in a hospital, home, or nursing home, caregivers cannot always monitor bedridden patients. Patients may choose to get up and walk without caregivers because they suffer from dementia or do not want to bother caregivers, which often leads to falls due to physical weakness.

　　The small FallSaver patch is worn on the patient's thigh and provides continuous monitoring of the patient's movements for up to two weeks, specifically identifying attempts to stand and walk. The FallSaver unit sounds an alarm and sends a radio signal to a nurse call station or a radio carried by a caregiver, who will be able to rush to the bedside to assist with mobility before the patient falls. This is a device that has been shown in clinical trials to significantly reduce falls and fall-related injuries in this high-risk population.

Figure 2 FallSaver

　　FallSaver also uses ADXL323 and ADX-L335 accelerometers, which provide motion information in digital format, enabling fast algorithmic analysis of motion patterns. In addition to the accelerometers mentioned above, next-generation three-axis accelerometers offer high levels of functionality at lower power consumption and smaller size, such as ADI's ADXL345 and ADXL346.

　　Two key issues for future home healthcare devices are connectivity and power . In many cases, accurately providing clinical readings from diagnostic equipment to healthcare professionals is as important as providing self-care to patients. For example, diabetes management. Another example is that current ECG (electrocardiogram) waveforms can be printed out or sent via electronic communication to provide information to clinicians.

　　Previously, to achieve this functionality, the ECG instrument needed to be connected directly to the computer, exposing the patient to a potential risk of electric shock. The recently introduced ADuM4160 USB isolator from Analog Devices overcomes this problem, providing complete electrical isolation between the patient and the computer and network, while still supporting the full functionality of the ECG and maintaining connectivity to the computer.

The measurement front end also requires a small amount of power to drive the amplifiers and data converters 　　used to acquire and digitize ECG signals . The isolated power is provided by the AD?Zim5000 DC-DC converter, which eliminates the need to charge and replace batteries. Such devices can also be used in the design of many home healthcare devices that require direct electrical contact with patients. They also have the ability to connect directly to a computer via USB, providing full functionality for storage, analysis, and result transmission. These technologies enable medical device designers to more easily meet the latest IEC60601 requirements.

　　By developing innovative ICs, semiconductor companies are improving the quality of healthcare for patients around the world. Design engineers who create the latest home healthcare systems are working to invent life-changing products based on semiconductor devices for disease management, health care, and drug delivery.

　　Many advances in semiconductor technology for portable and home healthcare products have been inspired by major advances in other portable consumer products, such as cell phones and media players. This is especially true in the areas of power management, motion detection, and RF transmission. However, expertise in precision signal amplification, conversion, and processing remains essential for detecting and analyzing low-level, complex clinical information.

　　These developments are also supported, promoted and certified by the Continua Health Alliance, a non-profit, open industry alliance of the best healthcare and technology companies to improve the quality of personal healthcare. Continua has more than 200 member companies around the world committed to building a system of interoperable personal health solutions, extending those solutions to the home with knowledge to foster independent, autonomous personal healthcare capabilities and provide truly personalized health and wellness management opportunities. The Continua Health Alliance is also establishing design standards and providing certification for those standards to build trust for healthcare providers and consumers when they choose and use the devices provided by these projects. The growing demand for home medical devices has led to increasingly complex system requirements, requiring medical device designers to reduce size, improve ease of use, and improve performance of the next generation of portable medical devices. These new system-level requirements mean that analog semiconductor manufacturers must meet the challenge and develop breakthrough module ICs to enable the design of next-generation products. The focus of design development is on how to develop future innovative features of medical devices, which increasingly depends on the continuous and effective sharing of information between system and analog IC designers.