The recommendations provided below have changed. This recall involves removing certain devices from where they are used or sold. The FDA has identified this recall as the most serious type. This device may cause serious injury or death if you continue to use it.

Affected Product

The FDA is aware that Hamilton Medical has issued a letter to affected customers recommending certain coaxial breathing circuit sets used with HAMILTON-C1, HAMILTON T-1, and HAMILTON-MR1 ventilators be removed from where they are used or sold.

Affected devices:

Full List of Affected Lots

What to Do

Do not use affected coaxial breathing circuit sets. Check your stock for affected item and lot numbers. 

Hamilton Medical issued a letter on May 22, to provide recommendations for affected customers. On July 01, Hamilton Medical issued a follow-up letter to provide updated guidance regarding breathing circuit use. Hamilton Medical recommends affected users take the following actions:

• Immediately check your stock for the affected item and lot numbers. Quarantine all affected product for return to Hamilton Medical for replacement.
• Inform all potential users of affected coaxial breathing circuit sets about this issue and post the provided notice in your facility. Make sure recommended actions are followed.

Reason for Recall

Hamilton Medical stated that certain lots of coaxial breathing circuit sets preassembled with an expiratory valve set do not perform as intended. In some cases, the expiratory valve membrane adhered to the sealing ring on the body of the expiratory valve, impairing valve opening and expiratory gas flow. The issue is not detected during the pre-operative test of the ventilator unless a test lung is actively ventilated. If the expiratory valve membrane is adhered to the sealing ring, the malfunction appears within the first breaths after ventilation is initiated.

When the expiratory gas flow is impeded, the end-expiratory pressure is too high, or the end-expiratory flow is too low. This will trigger the ventilator’s “Exhalation Obstructed” alarm.

An obstruction of expiratory flow results in inadequate ventilation and impaired gas exchange. Acute respiratory compromise due to impaired exhalation may result in inadequate ventilation and oxygen desaturation (hypoxemia).

As of July 2, Hamilton Medical has reported four serious injuries and no deaths associated with this issue.

Device Use

Hamilton Medical, Inc. ventilator coaxial breathing circuits are intended to connect HAMILTON-C1/T1/MR1 ventilators to a patient tube or respiratory mask during ventilation.

Contact Information

Customers in the U.S. with adverse reactions, quality problems, or questions about this issue should contact Hamilton Medical at complaints@hamiltonmedical.com or call 1-800-426-6331.

Additional FDA Resources  

1. FDA Enforcement Report
2. CDRH Medical Device Recall Database

Unique Device Identifier (UDI)  

The unique device identifier (UDI) helps identify individual medical devices sold in the United States from manufacturing through distribution to patient use. The UDI allows for more accurate reporting, reviewing, and analyzing of adverse event reports so that devices can be identified, and problems potentially corrected more quickly.  

• How do I recognize a UDI on a label?
• AccessGUDID database – Identify Your Medical Device
• Benefits of a UDI System

How do I report a problem?  

Health care professionals and consumers may report adverse reactions or quality problems they experienced using these devices to MedWatch: The FDA Safety Information and Adverse Event Reporting Program.

Timeline of Communication Updates

Date	Actions
08/11/2026	The FDA updated this communication to align with the recommendations in the latest customer notification.
07/02/2026	The FDA updated this communication to inform the public that this issue has been classified as a Class I Recall.
06/08/2026	The FDA issued an Early Alert communication to notify the public of a potentially high-risk device issue.