Features

The value of highly accurate, automated, and measurable testing for medical devices cannot be overestimated. As devices become more complex, and patient care becomes increasingly personalized, it’s never been more essential to ensure that each medical device performs reliably and exactly to specifications. Realistically, the first, tenth, and hundredth device off the production line must perform identically, regardless of the test station operator or other test environment variables.

Fig. 1 – The AriaTele transmitter transmits a patient’s ECG and SpO2 data wirelessly from the patient to a remote monitoring station.

To achieve such important goals, it’s imperative that the test environment and infrastructure be well defined, highly structured, and automated as much as possible. Recently, Spacelabs Healthcare, Snoqualmie, WA, a vendor of innovative medical devices including telemetry, patient monitoring, and anesthesia delivery and ventilator systems, partnered with Averna Technologies, Montreal, Canada, a test engineering firm that specializes in producing multifunction, modular, and automated test stations for clients in multiple industries.

A Multiple Test Station Project

This collaborative initiative required the development of 10 different standalone test stations to validate the functionality of Spacelabs’ telemetry transmission and reception modules, as well as an anesthesia delivery and ventilator system, from printed circuit board (PCB) to final assembly testing. This article will focus on just one test station for a new product—the AriaTele transmitter, formerly Salish Telemetry Transmitter (STT)—in order to explain how Averna designed and implemented a next-generation test system to achieve Spacelabs’ goal of automating and accelerating its electrical-mechanical performance testing.

The STT, shown in Figure 1, transmits a patient’s electrocardiogram (ECG) and oxygen saturation (SpO2) data wirelessly from the patient to a remote monitoring station. This article documents Averna’s implementation of the test station for the STT units and covers instruments, fixtures, test architecture, and test management software, explaining how they combined to increase Spacelabs’ testing automation and device throughput. Other project benefits include a paperless test environment, centralized test package distribution, and database-driven test results and analytics.

Flexible Test System Design

With the wide range of products to be tested, Averna and Spacelabs decided early in the project to architect the multiple test stations based on standard 19-inch racks and, wherever possible, modular radio frequency (RF) test instruments, such as PXI and PXIe from National Instruments. For the test sequencing, Averna employed the manufacturing industry standard of NI TestStand and LabVIEW. In addition, application-specific instruments were implemented to recreate Spacelabs’ product environment. For example, the STT test station, shown in Figure 2, comprises an ECG simulator, an SpO2 simulator, and a telemetry receiver (a Spacelabs’ product functioning as a captive device) in order to produce the necessary real-world RF and medical data environment for testing each STT unit.

An Intelligent Fixture Holds the UUTs

To keep operator intervention to a minimum, the STT test station’s fixture features a custom sliding base plate that ensures easy unit loading/unloading, uniform unit under test (UUT) positioning and repeatable RF measurements. The fixture’s integrated RF capabilities, such as Bluetooth, antenna coupler, and a breakout circuit PCB assembly, enable testing the UUT over wired and wireless interfaces from 100 MHz to 5 GHz, ensuring reliable measurements. To prevent any situation that could alter the integrity of the RF propagation conditions, the fixture has a plexiglass cover that closes over the UUT during testing. (See Figure 3)

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