Page 34 - EE Times Europe Magazine | April2019

34 EE|Times EUROPE

MEDICAL
Addressing the Challenges of Designing

for Medical Markets

By Maurizio Di Paolo Emilio

rogress in electronics technology has made it possible to create
increasingly safe, compact medical devices with the lowest
degree of invasiveness, but challenges remain in meeting strict
Psafety standards, providing wireless connectivity, and operating
within highly constricted power budgets.
An electromedical device is defined as an electronic device with
a part that can be applied directly to the subject or used to transfer
energy to or from the patient. Applications include diagnosis, treat-
ment, and monitoring of the patient’s health conditions, as well as
alleviating or even eliminating pain.
Safety, both for the patient and health-care professionals, is the
first requirement with which an electromedical device must comply.
The IEC 60601 family of standards sets the requirements for safety, Figure 1: The Synergy S1 MCU series (Image: Renesas Electronics)
performance, and electromagnetic compatibility of electromedical
equipment. Compliance with IEC 60601 standards can be achieved only temperature, heart rate, blood pressure, blood oxygenation, and body
through careful evaluation of all phases of the product development movements. Wearables that measure these vital signs make it possible
cycle, starting from the selec- to provide timely assistance if any of the parameters are abnormal,
Whether a device is tion of the components. helping to save lives.
Electrical insulation
Wearable medical devices represent important challenges for elec-
entirely new or a retrofit is directly connected to tronic designers, however.
Power absorption must be kept to a minimum, guaranteeing long
to which connectivity the issue involving safety. battery life to the battery-powered device. This factor influences the
To meet the stringent
has been added, it must requirements imposed by choice of components, orienting toward low-power solutions with the
undergo a rigorous regulations, it is necessary possibility of operating in low-absorption sleep mode. The mechanical
constraints, related to size and weight, also affect the design activity by
to guarantee high galvanic
certification process. isolation of the circuits in the favoring the use of low-profile miniaturized components mounted on
equipment, using barriers or extremely compact PCBs.
other protection solutions Another important requirement for wearable electromedical devices
such as optocouplers or transformers. In addition, leakage currents is connectivity: Through a Bluetooth interface (typically Bluetooth Low
must be minimized — and, better yet, eliminated. Energy [BLE]), mobile network, or Wi-Fi, it is possible to connect to
Class III electromedical devices and active implantable devices such an application or gateway that can acquire sensor measurements and
as pacemakers and artificial hearts present the highest level of risk. remotely control device operation.
Medical electronic devices that fall under the lower risk classes (IIa, IIb,
and I) of IEC 60601 include X-ray diagnostic equipment, surgical lasers, CONNECTED DEVICES
ultrasound equipment, and digital clinical thermometers. Connectivity is not the exclusive domain of wearable devices but
The spread of the internet and IoT infrastructure has paved the way concerns a wider category of electromedical equipment. The market for
for devices that monitor patients’ vital parameters or schedule or con- connected electromedical devices is booming, but that underscores the
trol the administration of drug doses. Solutions of this type have made need to increase efficiency, reduce the costs of therapeutic treatment,
it possible to achieve considerable savings on health-related expenses and improve the treatments provided to patients.
and to improve the efficiency and quality of the therapies provided. Electromedical devices relying on IoT infrastructure allow patients
The key factors for the success of these innovative systems are connec- to be discharged more quickly or even avoid hospitalization, reducing
tivity and wearability. health-care costs. Health-care devices such as insulin pumps, defibril-
lators, CPAPs, cardiac monitoring devices, and oxygen cylinders can
WEARABLE DEVICES now integrate remote-monitoring functionality, providing patients and
A wearable electromedical device is an autonomous, non-invasive caregivers with valuable real-time information without being tied to a
device capable of performing a specific medical function (such as mon- hospital or health-care facility.
itoring or dosing drugs) over an extended period. “Wearable” implies Connected medical devices must be able to connect to the cloud
that the equipment must be supported directly by the human body or infrastructure of the health-care system and must therefore be
by clothing. equipped with a reliable antenna and network interface. A critical fac-
Wearable devices, which have had exponential growth in the last tor, often underestimated by companies that intend to place connected
decade, can be grouped into three categories: monitoring devices, electromedical devices on the market, concerns the certification pro-
rehabilitation devices, and wearable medical aids. The last category cesses of wireless devices. In North America, for example, certification
includes all devices designed to provide long-term care to patients with is separate from FDA tests and is required for all wireless devices.
temporary or permanent disabilities. Regardless of whether a device is totally new or is the retrofit of an
Measurements and vital signs that can be monitored include car- existing device to which connectivity has been added, it is necessary
diac electrical activity (electrocardiogram [ECG]), respiration, body to go through a rigorous certification process not only with the FCC

APRIL 2020 | www.eetimes.eu