Test-drive your internet of medical things

Effective manufacturing test has an important role to play in ensuring quality of connected medical devices. Here is how it can help

SOOK-HUA WONG

The advent of IoT is driving transformation in healthcare. Rising healthcare cost and consumer demands for better healthcare delivery are driving widespread use of IoT in healthcare. This evolution is commonly known as the Internet of Medical Things (IoMT). Today, we can easily find medical devices that are connected, such as ultrasound imaging systems, glucose monitors, bedside monitors, pacemakers, hearing aids, and wearable health monitors. With IoMT devices, noncritical patients can stay at home and be monitored through these devices to decrease hospital admissions and reduce costs. The overall IoMT market is expected to grow from USD72.5 billion in 2020 to USD188.2 billion by 2025, at a compound annual growth rate (CAGR) of 21.0%. We will see the IoT greatly influencing all aspect of healthcare segment, from monitoring, to diagnostic, to surgery and patient care.

Medical device manufacturers face unique challenges when incorporating IoT. Many medical devices are used in mission-critical applications. Therefore, they must be very reliable and long lasting. The wireless connectivity needs to always-on and reliable 24/7 year-round, and it needs to work seamlessly in difficult physical environments. These requirements are pressuring medical device manufacturers to implement reliable, efficient, and cost-effective manufacturing test strategies.

The importance of effective manufacturing test

Many medical devices are subjected to thorough characterization during the design stage to ensure device quality. However, in manufacturing, assembly process variation, supply chain component deviation, test system repeatability, and operator handling errors can introduce failure into the device. Some of these defects may not be detected during manufacturing test due to lack of coverage in the test system. Marginally passed units may cause field failures during actual usage due to degraded performance.

To stay competitive in the market, manufacturing tests are normally optimized to achieve low cost-oftest with fast test time to meet market cost expectation. The device may only be tested under certain minimum conditions deemed sufficient. For instance, a wireless medical device OEM recently faced issues with the effectiveness of their manufacturing test setup. A custom version of the Bluetooth Low Energy (BLE) device managed to pass all manufacturing tests but was later found to have intermittent connection issues. After trouble shooting, it was found that device had a distorted antenna pattern, causing much lower power in some of its BLE channels. In production testing, only a very simple connection test was performed that was not able to catch these intermittent connection issues during actual operation.

Capital equipment cost vs. potential saving

A defect that is detected during initial manufacturing phases may not cost a lot to fix. However, the cost increases exponentially as the detection happens after production test or in the field during end user’s applications.