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  5. UPDATE: Potential Risk of Infection When Using Heater-Cooler Devices - Letter to Health Care Providers
  1. Letters to Health Care Providers

UPDATE: Potential Risk of Infection When Using Heater-Cooler Devices - Letter to Health Care Providers

Update: On June 14, 2022, the heater-cooler device web page was updated to provide new information about ongoing efforts of the FDA and industry to bring to market innovative devices that can help mitigate Nontuberculous mycobacteria (NTM) infections in patients, which included the clearance of a system that utilizes a glycol-based heat transfer fluid (HTF) instead of water.

The FDA continues to monitor the risk of infection with the use of water-based heater-cooler devices, and will continue to engage with manufacturers, health care facilities, and public health experts in evaluating new design features for heater-cooler devices.

October 13, 2021

The U.S. Food and Drug Administration (FDA) continues to monitor the risk of Nontuberculous mycobacteria (NTM) infections in patients who have undergone cardiothoracic surgery using heater-cooler devices, and to collaborate with stakeholders including public health partners, manufacturers, and experts to evaluate additional strategies to reduce the risk of infection from using these devices during cardiothoracic surgery.

Today, the FDA is providing updated information from our ongoing evaluation and monitoring of actions being taken by heater-cooler manufacturers.

Two heater-cooler manufacturers (CardioQuip and Gentherm Medical LLC) announced voluntary recalls for updated labeling with interim mitigation strategies to help reduce the risk of NTM infections in patients when using these devices, while these manufacturers complete further testing for cleaning and disinfection validation, and aerosolization.

Manufacturer Model Recall Notice

MCH-1000(i) Cooler Heater
MCH-1000(m) Cooler Heater

CardioQuip Customer Letter
Initiated July 30, 2021
Gentherm Medical LLC Hemotherm CE Dual Reservoir
Cooler/Heater, Model 400CE
Gentherm Customer Letter
Initiated June 17, 2021

Two manufacturers (Terumo and Maquet) announced voluntary recalls to tell facilities to discontinue use of their heater-cooler devices because these manufacturers will not be pursuing a cleaning and disinfection protocol that addresses the risks of NTM infection.

Manufacturer Model Recall Notice – Discontinue Use
Maquet Heater Cooler Unit HCU 30 Maquet Customer Letter
Initiated July 14, 2021
Terumo Sarns TCM/TCM II Cooling and Heating Systems
HX2 Temperature Management Systems
Terumo Customer Letter
Initiated April 30, 2021

As previously announced in February 2020, the LivaNova Heater-Cooler System 3T was cleared with changes to help reduce the risk of patient infections, with validated cleaning and disinfection instructions and the 3T Aerosol Collection Set to reduce (but not eliminate) the risk of potential emission of aerosols.

The FDA wants to ensure that health care providers and users are aware to discontinue use of the Maquet and Terumo heater-cooler devices, and of the interim mitigations from CardioQuip and Gentherm Medical LLC. The FDA is continuing to work with CardioQuip and Gentherm Medical LLC to ensure they provide test results on cleaning and disinfection validation as well as aerosolization. The FDA will continue to work with manufacturers on strategies to minimize the risk of NTM patient infection.


For specific heater-cooler devices in your facility, review the applicable recall notices from each manufacturer or contact the manufacturer directly for more information.

The FDA recommendations from our September 2020 letter to health care providers (Archived) have not changed, and these are repeated below:

Health care providers and users should review the current recommendations from the FDA for the use of any heater-cooler device to help reduce the risk of NTM infections in patients when using these devices during cardiothoracic surgeries:

  • Be aware that heater-cooler devices are important in patient care. In appropriately selected patients, the benefits of temperature control during open chest cardiothoracic procedures generally outweigh the risk of infection transmission associated with the use of these devices.
  • Strictly adhere to the cleaning and disinfection instructions provided in the manufacturer's heater-cooler device labeling. Ensure you have the most current version of the manufacturer's instructions for use readily available for staff who interact with these devices.
  • DO NOT use tap water to rinse, fill, refill, or top-off heater-cooler water tanks since this may introduce NTM organisms. Use only sterile water or water that has been passed through a filter of less than or equal to 0.22 microns. When making ice needed for use in the heater-cooler, use only sterile water or water that has been passed through a filter of less than or equal to 0.22 microns. Deionized water and reverse osmosis-treated water are not recommended because they may promote corrosion of the metal components of the system.
  • Always direct and/or channel the heater-cooler device's exhaust vent(s) away from the surgical/sterile fields and toward an operating room exhaust vent during device set-up and surgical procedures as well as after use to mitigate the risk of aerosolized heater-cooler tank water reaching the sterile field.
  • Establish regular cleaning, disinfection, and maintenance schedules for heater-cooler devices according to the manufacturer's instructions to minimize the risk of device contamination and patient infection.
    • Be aware that not following the heater-cooler manufacturer's cleaning instructions (frequency of cleaning and disinfection, strength of disinfectants used, and so forth) can damage the device.
    • Follow a comprehensive quality control program for maintenance, cleaning, and disinfection of heater-cooler devices. This may include written procedures for monitoring adherence to the program and documenting set up, cleaning, and disinfection processes before and after use.
    • Use new accessories, tubing, and connectors to prevent possible recontamination when using a different heater-cooler device.
    • Be aware that device contamination may also occur from other sources such as environmental contamination or device contact with contaminated accessories.
    • Clean, disinfect, and exchange heater-cooler and accessory tubing following manufacturer instructions.
    • Follow manufacturer instructions for storage of heater-cooler devices and accessories when not in use, which may include removing all water from the device and tubing.
  • Immediately remove from service heater-cooler devices that show discoloration or cloudiness in the fluid lines/circuits. This may indicate contamination. Consult your hospital infection control officials to perform the appropriate follow up measures and report events of device contamination to the manufacturer.
  • Consider performing environmental, air, and water sampling and monitoring if heater-cooler contamination is suspected. Environmental monitoring requires specialized expertise and equipment to collect and process samples, which may not be feasible in all facilities.
  • Patients suspected of an infection associated with heater-cooler devices or exposed to a contaminated heater-cooler device should be notified and evaluated. Health care facilities should follow their internal procedures for notifying and evaluating patients.
  • Report any issues with heater-cooler devices to the FDA, including if you suspect heater-cooler devices have led to patient infections or any type of contamination of a heater-cooler device. See Reporting Problems to the FDA below.


Heater-cooler devices are commonly used during surgeries to warm or cool a patient to improve medical care and patient outcomes. Heater-cooler devices have water tanks that provide temperature-controlled water to external heat exchangers or warming/cooling blankets through closed circuits. Although the water in the circuits does not come into direct contact with the patient, there is the potential for contaminated water to enter other parts of the device and aerosolize. This could send bacteria through the air and through the device's exhaust vent or other unsealed pathways, into the environment, and to the patient.

The FDA is aware that the use of heater-cooler devices has been associated with NTM infections, primarily in patients undergoing cardiothoracic surgical procedures. NTM organisms are widespread in nature and can be found in soil and water, including tap water sources. They are typically not harmful, but in rare cases may cause infections or death in very ill patients and in individuals with compromised immune systems.

While the FDA believes that NTM infections in patients who have undergone cardiothoracic surgery with use of a heater-cooler device are rare, health care providers and users should be aware that these NTM infections can and do occur. Because patients infected with NTM may not develop symptoms and signs of infection for months to years after initial exposure, it is possible that some cases have not been reported to the FDA. We are reminding health care providers and users to be aware of and remain vigilant for the potential risk of NTM infections in patients who have undergone cardiothoracic surgeries using any heater-cooler device. The FDA is actively seeking prompt reporting of adverse events or suspected adverse events from users of heater-cooler devices in order to continue our evaluation of this issue.

FDA Actions

For a complete listing of actions the FDA has taken on heater-cooler devices, see FDA's Ongoing Evaluation and Continued Monitoring of Reports of Nontuberculous Mycobacteria Infections Associated with Heater-Cooler Devices.

The FDA continues to engage with manufacturers, health care facilities, and the Centers for Disease Control and Prevention (CDC) in evaluating information about the risk of NTM patient infection with use of heater-cooler devices, and mitigation measures to minimize patient exposure such as possible design changes and revised cleaning and disinfection instructions. The FDA will continue to provide updates on the status of each manufacturer’s testing for cleaning and disinfection validation and aerosolization.

Reporting Problems to the FDA

The FDA encourages health care providers and users to report any adverse events or suspected adverse events experienced with any heater-cooler devices, including patient infection, device contamination, or difficulty following manufacturer instructions for use.

Prompt reporting of adverse events can help the FDA identify and better understand the risks associated with medical devices.

Contact Information

If you have questions about this letter, contact the Division of Industry and Consumer Education (DICE):

Additional Resources

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