FDA cites ZOLL over MRI ventilator labeling gaps

ZOLL Medical has received an FDA warning letter citing quality-system violations involving its 731 Series MRI-compatible ventilators.

The letter is dated April 30, 2026, but FDA’s warning-letter page was published on June 16, 2026. That timing matters because the public document describes required actions after earlier ZOLL responses in 2025, rather than a newly opened 15-day response window.

FDA inspected ZOLL’s Chelmsford, MA, facility from February 27, 2025, through April 15, 2025. The agency said the site manufactures X Series/Advanced automated external defibrillators, ZOLL MRI Compatible 731 Ventilators, OneStep electrodes, and Accuvent Sensors.

MRI labeling was a central issue in the warning letter. FDA said the Z Vent Ventilator is intended for use with 1.5T and 3T clinical scanners, but MRI compatibility testing was performed only with a 3T MRI scanner.

No documented rationale was provided for omitting 1.5T testing, according to the agency. FDA also said the labeling did not specify how far the ventilator should be placed when used with 1.5T MRI equipment.

A July 18, 2024, complaint involved use of the Z Vent Ventilator near 1.5T MRI equipment. FDA said the customer reported discrepancies in imaging quality and confirmed the ventilator had been used near the MRI system.

The warning letter also cited complaint-handling and corrective-action issues. FDA said CAPA CA 90 was opened in April 2024 for MRI compatibility nonconformances involving 731 Series Ventilators and later led to a Class I recall.

The 2024 recall involved missing MRI safety information in operator guides and quick-reference guides. FDA said the missing information could lead users to place the ventilator too close to an MRI machine, which could cause alarms, malfunction, or unexpected shutdown.

Risk analysis was another cited area. For the 731 ventilator MRI compatibility issue, FDA said ZOLL calculated risk using 24 malfunction reports and 27 complaints, while investigators identified 50 complaints from 2016 to 2024.

Medical-device reporting was also included in the letter. FDA said one ventilator incident involving insufficient instructions and unexpected shutdown near MRI was reportable within 30 calendar days, but the corresponding MDR was received months later.

The letter required ZOLL to respond within 15 business days of receipt. FDA’s public warning-letter page does not show a closeout letter or public resolution status on the article publication date.