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Safety Information

Trans-Tasman Early Warning System — Alert Communication

Heater-cooler devices used during cardiac surgery: risk of infection with Nontuberculous Mycobacterium species – advice and recommendations

31 August 2016

Products Affected
Information for consumers and caregivers
Information for health care professionals
Advice for health care professionals and facilities
Recommendations for treating physicians
What Action is Medsafe taking?
How to report adverse events
Further informaton


Medsafe is alerting health care professionals and facilities about a potential link between the use of heater-cooler devices, particularly in open cardiac surgery, and infections with non-tuberculous mycobacteria (NTM).

This alert provides information and recommendations to health care professionals about the use and maintenance of these devices and their component parts.

One case of a surgical site infection with non-tuberculous mycobacteria (NTM) has been reported in New Zealand in a patient that had previously undergone open chest cardiothoracic surgery and where a heater-cooler device was used during surgery. Similar cases have been reported internationally,

Heater-cooler devices are used to warm or cool a patient to optimise medical care and improve patient outcomes. In cardiothoracic surgery, heater-cooler devices are used within the operating theatre to control a patient’s temperature.

Heater-cooler devices contain 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 or to aerosolise, transmitting bacteria through the air via the device’s exhaust vent into the environment and to the patient. The exact route of transmission, however, is unknown.

NTMs are wide spread in nature and although not known to be harmful to healthy individuals, have been found to cause infections in very ill or immunocompromised patients or in situations where prosthetic material was implanted. One of the NTM organisms identified – Mycobacterium chimaera – has recently been linked to infections with heater-cooler devices. The organism is slow-growing, so infections may present some months (or years) after exposure.

Products Affected

All brands of heater – cooler devices may be affected by this issue.

Information for consumers and caregivers

If you, or someone you provide care for, has had open cardiac surgery and you are concerned about this issue, please consult a health care professional.


Information for health care professionals


There have been reports internationally of surgical site infections with the unusual mycobacterial species, Mycobacterium chimaera, in patients who have undergone cardiac surgery.  This surgery has involved open cardiac procedures where medical devices such as cardiac valves have been implanted.  Investigations have linked these infections with contaminated heater-cooler devices.

Non-tuberculous mycobacteria (NTM) include a number of different bacterial species many of which are widespread in nature and can be found in water, including tap water.  They are not usually a major cause of infection in the community, however, in rare cases may cause infection in very ill or immunocompromised patients or in situations where prosthetic material was implanted.  The organism is slow-growing so may present as an infection some months or years after exposure.

The exact route of transmission is unknown, however, studies suggest that if bacterial contamination of the water within the device occurs, there is potential for the device to transmit bacteria through the operating environment air by aerosol via the device's exhaust vent.

Other regulators have received reports of infections, but the overall number of cases is unclear.  The United States FDA had received 40 reports of NTM infections potentially associated with these devices by 1 April 2016, the majority of these reports were made in 2015.

Some suppliers of heater-cooler devices used in cardiothoracic surgery have updated their instructions for use and provided recommendations on how to reduce the risk of water contamination and on testing for the presence of the organism.


Advice for health care professionals and facilities

In addition to standard procedures, Medsafe recommends the following:

  • Consult your infection prevention and control service on how to adhere to the decontamination and disinfection instructions provided by the manufacturer of the device.
  • Some device suppliers have updated their instructions for use documents via the ‘recall for product correction’ notification system.  Ensure that this updated information is available and has been implemented.
  • Contact the New Zealand supplier if you have any questions about the instructions for use or processes for cleaning the device.
  • If your facility is undertaking microbiological screening of water in heater-cooler devices and / or operating theatres, consider the following:
    • Some manufacturers are recommending two methods – culture of heterotrophic plate counts (HPC) and mycobacterial cultures
    • Environmental samples for HPC should be submitted to a suitably accredited environmental testing laboratory and tested using validated methods
    • Mycobacterial cultures of environmental samples require specialised expertise and should be submitted to a laboratory that cultures for mycobacteria.
    • Protocols should take account of the delay in receiving results from mycobacterial cultures, which may take 6 – 8 weeks
  • Ensure that you regularly replace the lines as recommended by the device supplier Immediately remove any device where the fluid lines are discoloured or show cloudiness in the fluid as this may indicate bacterial growth. If this occurs, consult the infection prevention and control service for advice on follow-up measures.
  • Facilities are encouraged to develop policies and procedures on how to address this potential issue. This should involve contingency plans for the use of alternative equipment.
  • Usual procedures should be followed for assessing patients and notifying cases.
If a device tests positive for NTM:
  • Consult your infection prevention and control service and clinical teams to determine the most appropriate action for the facility.
  • Review the current protocol for decontaminating the device and ensure that it is in line with the device suppliers recommendations.
  • Implement the appropriate protocol for decontaminating the device.
  • Make arrangements for the use of alternative equipment, if required.
  • Report the positive result in line with your facility protocols.
  • Report the result to Medsafe and to the New Zealand device supplier.
If a patient tests positive for NTM following surgery where a heater-cooler device was used, consider the following steps:
  • Contact the infectious diseases service within your facility for advice on appropriate patient management and follow-up.
  • Do not use the device the patient has been exposed to (if known) and implement the appropriate testing protocol.
  • Report the positive result according to facility protocols.
  • Report the positive result to Medsafe and the New Zealand device supplier.
Patient 'look-backs' following exposure

Currently there are no evidence-based guidelines available on the follow-up of patients who have been exposed to a contaminated device.

Implementing a 'look-back' may be complex because of the slow-growing nature of the organism. Screening of asymptomatic patients for NTM is not currently indicated. Medsafe recommends liaising with infection prevention and control services in your area to determine the most appropriate approach.


Recommendations for treating physicians

For patients who have undergone open cardiac surgery, especially those who have had heart valve replacements, consider:

  • Only a small number of cases have been identified globally so the risk to individual patients of NTM infections is thought to be very low.
  • Infection with NTM should be considered in patients with deep surgical site infections who have had cardiac surgery, particularly if conventional cultures are negative, if infections are not responding as expected, and in those with unusual presentations.
  • The diagnosis of NTM infections may require specialised microbiological techniques so consultation with a clinical microbiologist is recommended.
  • Consult with an infectious disease physician on the appropriate management of a patient with confirmed NTM.
  • Report any confirmed or suspected infections to Medsafe and the device supplier.


What Action is Medsafe Taking

  • Medsafe is actively monitoring the situation and is working with industry as it provides updated information on the decontamination and disinfection procedures for these products and their component parts.
  • Medsafe requests that all adverse events relating to the use of this type of equipment be reported as soon as possible. Information on making a report is detailed below.

The advice provided in this alert has been adapted from Australian advice provided by the TGA (Therapeutic Goods Administration) and peer-reviewed for New Zealand application.

How to report adverse events

Fax 04 819 6806
Online Submit a Medical Device Incident Report (Word 104 KB, 3 pages)
Post Compliance Management Branch, Medsafe, PO Box 5013, Wellington 6415

Further information


Australian TGA:



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