It's not surprising that state-of-the-art healthcare systems generate huge volumes of information. The quantity and its growth is spurring a range of improvements in electronics. For instance, the increase in patient-controlled medical devices mean simpler interfaces, which in turn requires more safeguards and processing power.
Electronic-component manufacturers are working on several fronts to help medical-device manufacturers. For instance, processor manufacturers are adding networking, signal processing, and cryptography to 32-bit processors for healthcare monitoring and other host and gateway applications. In addition, 8-bit microprocessors are using less power and network better, thus improving information delivery and control. And sensors are being improved to unobtrusively capture more data.
Healthcare personnel count on technology from device manufacturers to help them provide high quality healthcare under increasing cost pressures. And the portable and wearable-device trend puts a premium on light weight and low-power consumption.
A gateway in each room
Healthcare personnel have more sources of patient information than ever before. But mountains of information can be a barrier in an emergency if data is not recorded, analyzed, and responded to. An emerging application that addresses these issue consists of gateways that let doctors and nurses monitor and work with equipment locally and from a central base station. For example, nurses at a central station can securely and remotely monitor equipment such as respirators, heart monitors, and dosage controllers that are in different hospital rooms. Bedside equipment can be connected by Ethernet to microprocessor-based local monitoring gateways, or by serial RS-232 in the case of legacy devices. The gateway in each room would be wired to a central router and connected to the base station.
Microprocessors in medical gateways must allow connections to other devices and networks, work securely, and keep products useful for years. The latest generation of such microprocessors offers connectivity options such as multiple 10/100 Fast Ethernet controllers, Universal Serial Bus (USB), and queued serial peripheral interfaces. However, it would be computationally intensive to implement existing protocols such as SSL/TLS, Ipsec and IKE in software. Doing so would also significantly reduce overall systems performance.
A new generation of microprocessors, on the other hand, provides secure point-to-point communications across insecure Ethernet networks without sacrificing performance. For example, these microprocessors encrypt data from bedside equipment before it is transmitted by Ethernet to the central base station, where the data is decrypted and interpreted.
Healthcare personnel must also have access to this data while in the patient's room. This might be done through an Ethernet-connected bedside monitor. Adding a USB controller on a microprocessor lets product developers design-in system access through the gateway's USB-to-Ethernet adapter port, for instance, using a PDA with a USB On-The-Go port. USB-OTG is a supplement to the USB 2.0 specification. It adds hosting capability for connections to mobile devices and USB peripherals. This additional USB feature lets healthcare personnel track patient conditions in new ways. For instance, this gives nurses more flexibility when monitoring patients. They might download data from patient-monitoring systems to a medical PDA through a USB connection. Then they could either keep it on the portable device for quick reference or transfer it to another USB-enabled system for storage and possibly further analysis.
Tomorrow's operating theater today
Minimally invasive surgery is one factor behind the increasing complexity of equipment in operating theaters. New procedures need even more equipment such as monitors, cameras, scopes, and insufflators (devices that gently inflate surgical areas with CO2)). Such complexity increases the need for central management units that coordinate and control all mechanical and electrical systems in the operating room, including endoscopic and surgical equipment, the OR table, lighting and temperature, phone and video conferencing. Even during operations, it's vital that surgeons have easy access to patient information such as monitoring data, equipment diagnostics, and video records of the procedures. Information recorded during operations, such as video, surgeon commentary, patient monitoring data, and equipment diagnostic information, must be saved and backed up for reference.
The idea of the Integrated Operating Theater lets a voice or single device control all operating-theatre components. Voice control frees surgeons to concentrate on handling instruments. Such a theater requires microprocessors with a broad range of communications interfaces to deliver many functions on one piece of silicon. Perhaps the most important feature is support for the Controller Area Network (CAN) bus, a fault-tolerant communications protocol that provides secure data transfers between central control units and various OR equipment.
The latest microprocessors, such as the Freescale MCF548x ColdFire series, target next generation operating rooms, and also have multiple Ethernet controllers. These let the system connect through a network to a host computer for real-time data logging and backup. An external bus can be used to connect to an LCD or touch screen to monitor output, data input, and video or image viewing. An on-chip PCI controller simplifies connections to data storage and backup systems and also provides flexibility for adding connectivity, such as audio and video systems. A hardware encryption module secures fast data transfers between the operating system and LAN or WAN.
Designing for healthcare
Healthcare devices should have design goals of long service, simple operation, and low power consumption. To ensure a long service life, semiconductors aimed at healthcare devices have been designed with automotive temperature libraries and testing regimens. That means burn-in tests that simulate years of operation are done at -40 to +125°C. Electric current and data typically run through parts for 1,008 hours at 150°C. These standard-test conditions for automotive parts work in healthcare electronics because they ensure a long life of reliable operation. Other standard tests include electro-static discharge and highly accelerated stress testing (HAST), which subjects components to high temperature, high humidity, and high pressure that accelerates the corrosive effects of moisture.
Designing for simplicity is also important for in-home and wearable medical devices, such as insulin pumps, blood-pressure monitors, and portable defibrillators. Developers must assume users have little technical experience. One-button operation or a simple touch-screen GUI can make a big difference to users, particularly when they are disabled. As an example of simple yet capable design, consider an 8-bit microcontroller with an LCD driver, a 32-bit device with on-board Ethernet, or USB controllers that let designers more easily incorporate functions for peripherals that simplify the user interface and leave more real estate for more differentiating features. Adding more features can greatly improve long-term reliability by reducing the number of components and device interconnects, leading to more reliable and useful products.
Power consumption is another major concern for developers because many healthcare devices are portable, wearable, and even implanted. Hence, several circuit design techniques have been developed to tune semiconductors for low-power operation. The techniques include dual-threshold voltage features, well-biasing, dynamic voltage frequency scaling (DVFS), dynamic memory access, clock gating, and hardware and software partitioning.
Designing for compliance with FDA regulations is a big consideration for any medical product developer. Violating FDA rules can result in the suspension of product shipments and mandatory recalls, even criminal investigations. So designers build FDA approval into the development process. Semiconductor manufacturers can help product developers more easily conform to FDA regulations by providing semiconductors with proven reliability, longevity, and economy of use.