The rising costs of healthcare and hospitalizations, along with a rapidly aging population in the United States, were already moving the needle toward telehealth operations – routine and noncritical electronic monitoring of patient needs that can be attended to away from the healthcare facility setting. Then, COVID-19 struck and accelerated the use cases for telemedicine, as routine doctors’ visits can be conducted virtually.
Across the world, the demand for low-touch or virtual approaches to medical care and remote patient monitoring (RPM) is growing. RPM will increase at a compounded annual growth rate (CAGR) of a whopping 38.2 percent until 2025, according to research firm MarketsandMarkets. In just five years, the RPM segment will grow in value from USD $23.2 billion in 2020 to USD $117.1 billion in 2025.
Equally impressive is the fact the global telemedicine market, valued at $55.9 billion in 2020, will grow at a CAGR of 22.4 percent until 2028, according to Grandview Research.
The Basic RPM Device
The explosive growth of remote patient monitoring means an increased use of devices which lean on cellular or Bluetooth communications to transfer data for analysis.
The basic RPM system, no matter whether it’s being used for blood pressure or blood glucose or other health indicators, can be thought of as four components working in sync:
- A device with an IoT sensor
- An app through which the patient can access the data being measured
- The cloud infrastructure for secure data transmission
- End processing in the cloud, where the data is analyzed and acted on (data from Bluetooth sensor nodes can be aggregated at a network mesh gateway before relaying to the cloud for processing)
The growth of sensor-based devices, both remote and at the hospital, delivers many challenges with respect to electronics design. The biggest headache is related to electromagnetic interference (EMI). When many devices communicate at the same time, a lot of interference and noise generated can lead to faulty and missed signals.
Connected devices usually use the unlicensed 2.4 GHz band for Bluetooth and Wi-Fi connections to relay data, but this causes problems in health-critical applications. In order to avoid data congestion and to handle a large volume of devices using different communication protocols, system designers have to figure out how to route traffic intelligently. They do so by sorting devices into categories of critical functionality.
These applications typically fall into one of these buckets: real-time critical use cases, real-time non-critical use cases, remote control uses and office support uses.
Additional Criteria for Device Design
In addition to functioning together without too much EMI, medical devices have to check off the following factors:
Low power operation – Continuous monitoring can’t be an energy soak, so IoT devices (and those that run 24/7, in particular) need to be low-power
Offer smooth connectivity – It is not enough for data to be transmitted while the patient is in one mode and to be offline the next. Continuous RPM means devices have to ensure data transmission no matter the patient’s location or level of mobility. Seamless connectivity at required times and conditions is important for eHealth.
Cybersecure – Patient health information (PHI) is sensitive. Medical devices must ensure data is encrypted during transmission and anonymized when aggregated for analysis. Devices must be designed to comply with applicable laws to ensure anonymity and privacy in data collection and transmission.
Decreasing EMI Incidence
Traditional ways of decreasing EMI, whether in medical or automotive or other use cases, have involved adding capacitors to circuits. While the approach works, it bulks up size, which in turn can affect both product design and increase energy consumption. Spread spectrum or dithering, as applied to chip design, is another strategy that reduces EMI peaks by distributing the energy across multiple frequencies, thereby blunting its effect.
Moving away from chip design to managing entire systems, the two-chip solution (with two radios and an algorithm for traffic management) is one of the more exciting ways to manage EMI while catering specifically to load on communication channels.
One of the most intriguing developments is in the use of intelligent wireless communication through a cognitive radio solution. The key here is to use software to drive traffic efficiently. The cognitive radio system takes an inventory of all the medical devices that need to be accounted for and uses a cognitive radio controller. The system tracks less-used spectrum channels and modifies transmission accordingly. The cognitive radio system essentially acts like a traffic guard, surveying the landscape and making intelligent decisions about when to route traffic — and how.
The role of medical devices, IoT-driven or otherwise, in healthcare is growing. Procurement of related electronics is going to be challenging as these devices have to follow strict government guidelines and compete for effective communication in limited channels. Professionals use the best IoT sensors, low-energy beacons and more to assemble just the right systems to meet these complex needs.
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