URGENT, MEDICAL DEVICE FIELD ACTION

Products affected: 27740, 28324, 28362, 28363, 27948, 28944, 28945

Date Initiated: August 2025

Dear Valued Customer:
Masimo identified that certain Radius VSM devices, when not charged for prolonged periods, may develop over-discharged batteries. Masimo’s investigation has identified batteries in an over-discharged state are susceptible to damage (e.g., swelling), resulting in inaccurate detection of the remaining battery capacity. Inaccurate detection of the remaining battery capacity may mislead users to believe batteries are fully charged based on the displayed State of Charge (SOC) when they are not, which can lead to earlier-than-expected low battery alarms and reduced runtimes.

The Customer Notice applies to the specific Radius VSM part numbers (PNs: 27740, 28324, 28362, 28363, 29748, 29844, and 29845) with serial numbers within the following range: RV00000211 to RV00022178.

Risk to Health:
Masimo has concluded that the occurrence of State of Charge (SOC) and swelling of the batteries does not pose a risk to health. There have been no reports of injuries or adverse events resulting from the State of Charge (SOC) or swollen batteries. Masimo’s decision regarding this Customer Notice and the return of devices for repair or replacement was made to reduce the likelihood that customers would experience any inconvenience related to this issue.

No Impact to Other Products:
There is no impact on any other Masimo products.

ACTIONS TO BE TAKEN BY CUSTOMER:

• Please assess your inventory to identify if your Radius VSM device serial numbers are within the following range: RV00000211 to RV00022178.
• Assess the Radius VSM devices to see if the back cover of the housing has any visible signs of bowing.
• If the back cover of the Radius VSM is bowed, stop using the Radius VSM and contact Masimo to request a replacement. Extreme bowing would prevent the Radius VSM from docking.
• If you are unable to identify bowing in the Radius VSM back cover, you can continue to use the device while coordinating with Masimo to receive a replacement.
• If you have experienced reduced runtimes with the Radius VSM, contact Masimo to request a replacement.
• Please acknowledge that you have read and understood this notification and have followed the actions listed in this letter by completing and returning the forms attached to Masimo.

CONTACT CUSTOMER SUPPORT:
Masimo’s Customer Support is available at 1-800-916-1270 for US customers Monday through Friday from 6:00am -5:00pm PST for live assistance or 24 hours a day to leave a message and someone will contact you. For international customers local contact information can be found at https://www.mymasimo.com/contact-us/. Masimo Customer Support can also be contacted via email at customercare@masimo.com.

ADVERSE REACTIONS OR QUALITY PROBLEMS:
Any adverse reaction or quality problems experienced with the use of this product may be reported to the FDA’s MedWatch Adverse Event Reporting program online, by regular mail or by fax.

Masimo is committed to consistently providing high quality products and services to you, our customers. We apologize for any inconvenience this issue may have caused.

Sincerely,

Mathew Jimenez
SVP, Worldwide Quality & Compliance Masimo Corporation