A November 2018 FDA inspection has resulted in a warning letter for Zeller Power Products. The Wallace, ID-based company makes a replacement battery for Cardiac Science's PowerHeart Automated External Defibrillator (AED) G3.

FDA said its inspection revealed that Zeller didn't have design validation documentation to justify the battery's five-year shelf life and an operational guarantee of up to four years after installation. The firm also failed to validate software used on the battery's printed circuit boards.

A Zeller management representative provided the FDA investigator a product information sheet for the battery and said that statistics were most likely taken from the specifications of the OEM battery by Cardiac Science. The agency's investigators explained that the batteries produced by Zeller are not Cardiac Science products and the Zeller design and specifications must be validated.

The software installed on the printed circuit boards included in each battery also has not been validated, according to the warning letter. The software is written to make the battery compatible with the Cardiac Science defibrillator and is programmed during production to tell the device the battery has not been used and is ready for use, FDA noted. 

"The device has not been validated to determine that it conforms to OEM specifications or defined user needs and intended uses," the agency said in its letter to Zeller. "Furthermore, your response indicated that you have established a correlation between the firm’s five-year shelf life and the OEM’s self-discharging rate of cells, but it is unclear if you have verified and or validated the battery’s shelf life." 

FDA also noted in the letter that many of its observations from the November 2018 inspection were repeat observations from an earlier FDA inspection that took place in January 2016.

FDA acknowledged that the management representative provided records associated with the device component and finished device specifications, but these records did not identify documentation of a plan, inputs to create the device, outputs from those design plans and inputs, verification and or validation of the design, design review after each major project step, and a risk analysis for the design.

The company also fell short in terms of how it handles complaints, according to the letter. The firm's representative told the investigator that its most common complaints, such as the defibrillator not working when the replacement battery is installed, are usually resolved over the phone with instruction from the company on how to properly install the battery into the device. But, FDA noted, Zeller has not documented these activities to determine if further investigation was needed.

Similarly, FDA found that when customers returned the Zeller AED batteries for issues such as a disconnected battery wire, defective cells, and battery reporting as not calibrated, the returned goods authorization forms have not been documented as complaints and the company failed to include an evaluation for reporting adverse events to FDA. The problem with not documenting these things, the agency explained, is that there is no evidence that the final root cause for why the batteries were returned has been evaluated. Documentation also is needed to make sure negative trends are identified.