By Marcel Consée, Mouser Electronics

Healthcare can be deeply personal, and direct contact between patients and medical personnel remains vital. However, taking the relationship between doctors and nurses out of the equation can sometimes make sense. Medical crises such as the global COVID-19 pandemic accelerate the adoption of telehealth methods, even though the original idea behind that approach was improving healthcare in remote locations.

Technological advancements, together with economic pressure, have popularized the concept. To develop a telehealth system, we propose a straightforward approach using these considerations:

• Identify the scope of your design idea
• Identify benefits and target group
• Necessary infrastructure and security for the end product
• Functional safety issues
• Platforms and design ecosystems

What to design?

The term virtual healthcare interchanges with telehealth and telemedicine. The U.S. Health Resources and Services Administration and the U.S. Department of Health and Human Services define telemedicine as remote clinical services, such as diagnosis and monitoring. At the same time, telehealth includes preventative and curative-care delivery, including non-clinical applications such as administration and provider education. The World Health Organization describes telemedicine as encompassing all aspects of health care, including preventive care. In Europe, eHealth includes telehealth, electronic medical records, and other components of health information technology.

Who is it for?

Cloud or edge applications make the use of artificial intelligence (AI) feasible even for smaller practices. Some specialties in medicine have actually taken up AI techniques over the past few years. The most popular is radiology, where remote AI platforms routinely process imaging results from commercial vendors and research facilities.

The diagnosis itself strongly depends on the relationship between the patient and medical practitioner. AI can accurately diagnose many diseases—the most notorious being diabetes and cardiovascular disease (CVD), which rank among the top-10 causes of death worldwide. To address this high mortality rate, efforts to integrate various methods in getting an accurate diagnosis are being developed. Mobile blood pressure, heart rate monitors, and blood oxygen sensors have been used for years, but the advent of multi-sensor wristbands and sports watches has taken these devices to a new level. The amount of data collected by a device, such as an Apple Watch, is breathtaking. Doctors are cautious in trusting the 1-channel electrocardiogram (ECG) taken by these devices, but their alerts can advise the wearer to seek a thorough medical examination.

What do I need?

Virtual healthcare requires excellent communication infrastructure and ideal broadband connections combined with security software and hardware. Security is a significant issue in this kind of data, so encryption is vital for ensuring trust. This type of information holds a healthcare system together, and electronic health records include critical data such as medicine dosage, insurance information, and other personal information.

The amount of medical data is growing each year. Before COVID-19, researchers from Stanford University estimated an annual increase of 48 percent. This figure includes private information regarding patients, their health status, and insurance providers circulating in hospitals or doctor’s offices. Such sensitive information requires high levels of security for the patients.

That is why most countries have put rules in place to protect electronic personal health information that healthcare providers, health plans, and healthcare clearinghouses create, receive, use, or maintain.

Commonly, safeguards are categorized like this:

• Administrative: Assigning security responsibility to an individual and implementing security training.
• Physical: Protect electronic systems and data they hold by restricting access to electronically protected health information (ePHI) and using off-site backups.
• Technical: Automated processes such as authentication controls and encrypting data during transfer.

Cloud and edge architectures with adequate security measures can be useful because the exchange of medical data between clinical facilities, patients, researchers, and medical practitioners requires shifting enormous amounts of data.

Healthcare data and related applications have to comply with several data regulation laws such as Health Insurance Portability and Accountability Act (HIPAA), Health Information Technology for Economic and Clinical Health (HITECH), and General Data Protection Regulation (GDPR). Healthcare providers have to ensure compliance with the cloud-hosted data, which is not an easy task.

Is it safe?

Once the medical functionality of a device has been checked, the safety for the user and the patient (who can easily be the same person) must follow international guidelines. Electrical safety standards apply to medical appliances.

To help verify the functionality and safety of medical devices, electrical safety standards have been established in the U.S., Europe, and other parts of the world. Standards differ in criteria, measurements, and protocol, including general and specific medical device electrical safety standards. The primary standard for medical devices is IEC 60601. General requirements for protection against electric shock hazards are covered in IEC 60601.1, Section 3.

• In this standard, each instrument has a class:
  • Class I—Live part covered by basic insulation and protective earth
  • Class II—Live part covered by double or reinforced insulation
  • Class IP—Internal power supply
• Each patient applied part, or patient lead has a type:
  • Type B—Patient applied part earthed
  • Type BF—Patient applied part floating (surface conductor)
  • Type CF—Patient applied part floating for use in direct contact with the heart
• Additional important points regarding IEC 60601.1 include:
  • The use of up to 25A (AC) for protective earth testing
  • Leakage current is measured at 100 percent of mains voltage

Performance of dielectric strength/insulation testing is measured at 110 percent of mains voltage.

A newer IEC standard, IEC 62353, is used for medical device testing in hospitals. IEC 62353 was developed because IEC 60601.1 is a type-testing standard with no risk management criteria and is impractical for testing in the hospital environment.

IEC 62353 tests are performed on equipment before use on patients, during scheduled periodic testing, and after repair. This standard is for field (hospital) testing and does not address equipment design. In Annex E of the document, the manufacturer is asked to provide information on testing interval and procedure based on risk, typical usage, and device history. The minimum testing requirement for life support and other critical equipment is every 24 months.

Do I have to do everything by myself?

Billions of sensors monitor patients in hospitals and clinics around the world. Even before COVID-19, healthcare had extended, up to a point, beyond medical facilities and to homes and workplaces. The slow shift to more remote monitoring, care, and treatment rapidly accelerated in spring 2020.

Companies developing applications for first responders, seniors, and fitness face the same challenges and requirements from a design and development perspective. One of the major product groups for collecting health or fitness data is smartwatches or fitness wristbands. The Apple Watch is equipped with a built-in heart rate sensor, which uses both infrared and visible-light LEDs and photodiodes. Furthermore, it uses a position and acceleration sensor for detecting movement. Other manufacturers employ similar technology.

A fine example of medical sensor fusion is the MAX86150 Integrated Photoplethysmogram (PPG) and the Electrocardiogram Bio-Sensor Module by Maxim Integrated. For development purposes, the manufacturer provides the MAX86150 Evaluation Kit (Figure 1). ECG, PPG, and simultaneous ECG and PPG can be measured. When monitoring is active, the module uses IR Proximity Mode to detect the user’s fingers, and a red LED will turn on when a finger is near the module.

 Another type of development platform that might be closer to the end product is the MAXREFDES101 Health Sensor Platform 2.0 (Figure 2) from Maxim Integrated. The wrist-worn platform integrates a PPG analog-front-end (AFE) sensor (MAX86141), a biopotential AFE (MAX30001), a human body temperature sensor (MAX30205), and a microcontroller (MAX32630) with a power-management IC (MAX20303) and a 6-axis accelerometer/gyroscope. The complete platform encompasses a watch enclosure and a biometric sensor hub with an embedded heart-rate algorithm (MAX32664). Algorithm output and raw data can be streamed through Bluetooth to an Android app or PC GUI for demonstration, evaluation, and customized development.

 Designing power circuitry for smartwatches and other wearables can be challenging because of customer expectations, such as more functionality, longer battery life, and smaller size.

The Smart Watch Solution by Toshiba provides a reference design based on Toshiba discrete components, selected to get more performance in a smaller package. Toshiba offers an extensive portfolio of components such as tiny MOSFETs, diodes, and transistors in addition to feature-rich integrated circuits such as low-dropout regulator (LDO) regulators, Load Switches, and the smart eFuse IC, all designed to increase available board space, reduce passive current consumption, and ensure long battery life.

Whatever the final design, sensor fusion is the key to wearable health monitors. A good starting point for developing is a MikroE sensor Click board, such as the ECG 6 Click, used to develop ECG and Heart-Rate applications. The click features the Maxim Integrated MAX86150 Reflective Heart-Rate Monitor and Medical-Grade Pulse Oximeter. The board contains an integrated electrocardiogram, pulse oximeter, heart-rate monitor sensor module. The ECG 6 Click is suitable for fitness assistant devices, wearable devices, smartphones, and tablets.

 

Conclusion

Using a suitable development platform makes the design of virtual healthcare offerings easy. Of course, they harbor the danger of just designing a copycat product. However, telehealth and remote patient monitoring offer several benefits to patients and physicians. Virtual care has become increasingly popular because of efforts to provide the least expensive care in the most effective possible setting. The speed of adoption rises with health crises, but the development of communication infrastructure has to keep up.

 

As Technical Content Specialist, Marcel is the internal contact person for technical questions in Mouser’s EMEA marketing team. Originally a physicist, he used to work as an editor for special-interest magazines in electronics. In real life, he’s juggling two kids with too many chromosomes, a penchant for electronic gadgets, and a fondness for books and beer. Until now, none has dropped.