Mortara ELI 150c Interpretation Malfunction Repair Case Study

A Florida facility reported that their Mortara ELI 150c EKG machine was producing malfunctioning and duplicated interpretations. Accurate EKG interpretation is a critical diagnostic aid, so any perceived errors require immediate investigation. A PBES technician was dispatched to diagnose the issue and determine if it was a functional failure of the equipment.

Technician investigation

The technician's investigation focused on distinguishing between a hardware/performance failure and a software-based issue. The first step was to perform a hard reset to clear any transient errors. Following the reset, the technician ran multiple EKG simulations covering various clinical scenarios. During these tests, the technician observed that the ELI 150c was correctly reading and displaying the simulated waveforms, indicating that the core functional performance of the EKG was not compromised.

Root cause

Suspected: An internal software issue with the automated interpretation feature. The root cause was not definitively confirmed, as the issue appeared to be within the proprietary interpretation software, which cannot be adjusted by field service technicians.

• Functional performance failure (waveform acquisition)

Resolution

The technician performed a hard reset on the Mortara ELI 150c. Extensive simulations were then run to verify that the unit could accurately acquire and display waveforms, which it did successfully. The technician advised the client that the automated interpretation is a diagnostic aid and software-specific issues must be handled directly with the manufacturer (Welch Allyn/Baxter). It was also recommended that users always verify patient data, such as age and sex, is correctly entered to ensure the most accurate interpretation possible. Due to the age of the unit, replacement was suggested as a final option if the issue persists.

Verification

• Performance testing via simulations of various EKG scenarios

Verification ensures that the EKG's primary function—accurately acquiring and displaying electrical signals from the heart—is intact. By running simulations, the technician confirmed the hardware was working correctly, isolating the problem to the interpretation software layer.

Technician insight

An experienced technician knows to separate an EKG's data acquisition function from its interpretive software function. The report of 'duplicated interpretations' pointed towards a software glitch rather than a hardware problem like lead failure. By using simulations to confirm correct waveform reading, the technician efficiently ruled out a functional failure and identified the problem's likely source, saving time and providing the client with a clear path forward.

Understanding EKG Interpretation Errors

• Incorrect patient data entry (age, sex, weight)
• Poor electrode contact or lead placement
• Patient movement or muscle artifact
• Electromagnetic interference from other nearby devices
• Internal software or firmware glitches
• Faulty patient cable or lead wires

In this case, after a hard reset and testing, the issue was determined not to be a functional performance problem but rather a suspected software issue with the unit's automated interpretation feature.

FAQ

What is a 'hard reset' on a Mortara ELI 150c?

A hard reset is a process of completely power cycling the device to clear its temporary memory. It can sometimes resolve software glitches or transient errors without affecting stored data or settings.

Is the automated interpretation on an EKG machine always correct?

No. Automated interpretations are diagnostic aids designed to assist clinicians. They are based on algorithms and should always be reviewed and confirmed by a qualified medical professional.

Why did the technician test with simulations?

Simulations provide known, standard waveforms to the EKG machine. This allows a technician to verify if the machine can accurately read and display signals, independent of a live patient, to confirm its functional performance.

Why was the unit not repaired on-site?

The technician determined the issue was likely with the proprietary interpretation software. Field technicians typically cannot modify or repair this level of software, which requires direct support from the manufacturer, in this case, Welch Allyn/Baxter.