Infections associated with heater-cooler devices

Infections associated with heater-cooler devices

Consumers and health professionals are advised that the TGA has updated its information about mitigating the risk of Mycobacterium chimaera infections from heater-cooler devices. For more details see ‘Information for health professionals and facilities‘ below.

Heater-cooler devices are used within operating theatres to control the temperature of blood diverted to cardio-pulmonary bypass machines. Heater-cooler devices contain water tanks that provide temperature-controlled water for the operation of the device. This water does not come in contact with the patient.

In Australia heater cooler devices used in cardiac surgery are supplied by LivaNova (Sorin), Maquet and Medos Medizintechnik AG.

The TGA published advice about this issue in a web statement on 2 August and in the May edition of Medical Devices Safety Update.

The Australian Commission on Safety and Quality in Health Care (ACSQHC) issued New National Infection Control Guidance(link is external) relating to heater-cooler devices in September.

More than 50 patients worldwide have been identified with Mycobacterium chimaera infections after cardiac surgery. Cases of infection with Mycobacterium chimaera have been identified between three months and five years postoperatively. There is evidence to suggest that patients are infected when bacteria in the device’s water bath becomes airborne.

There has been a single case report in Australia. The patient involved in this case is recovering.

Infection is a recognised consequence of all surgery and up to 3-5% of patients develop valve infections within the first 5 years after valve surgery. The risk for mycobacterial infection from contaminated aerosols from heater-cooler devices is considered to be very low compared with the overall risk of surgical and valve infection.

The US Food and Drug Administration issued a safety communication(link is external) on 13 October in relation to contamination with Mycobacterium chimaera of one model of heater-cooler (Stӧckert 3T Heater-Cooler System by LivaNova (Sorin)).

Based on the currently available data, and as determined by genomic sequencing of organisms, theMycobacterium chimaera infections have been identified as a point source outbreak, with the heater-cooler units now believed to have been contaminated at the point of manufacture. The product affected is the Stӧckert 3T Heater-Cooler System (3T) manufactured in Germany by LivaNova. The manufacturer implemented post-production/pre-shipping disinfection procedures on 18 August 2014 that have reduced the risk for units manufactured after September 2014.

Some sponsors of heater-cooler devices are undertaking recall actions in Australia (for example, updating the Instructions for Use regarding disinfection) to mitigate the risk of contamination. Recall actions are published in the System for Australian Recall Actions(link is external) database.

TGA has received reports for Mycobacteria chimaera contamination of Stӧckert 3T Heater-Cooler System (3T) devices.

Testing of Stӧckert 3T Heater-Cooler System (3T) devices by hospitals in Australia has identified that 25% of these devices have tested positive for the Mycobacterium chimaera organism or other organisms. All devices that tested positive were manufactured prior to September 2014.

The overall issue of microbial contamination of heater-cooler-units was also highlighted in the United States when the University of Washington Medical Center reported contamination of three heater-cooler devices(link is external)with Legionella sp. bacteria in September. Four patients were diagnosed with legionellosis (Legionnaires’ disease) and two died. The source of the outbreak was linked to the hospital’s water supply, as bacteria were also detected in an ice machine and two sinks in the hospital’s cardiac unit. There have been no reports in Australia of heater-cooler devices being contaminated with Legionella sp. bacteria.

The TGA will continue to consult with an expert advisory panel regarding the issue of microbiological contamination of heater-cooler devices and to monitor the issue.

Information for consumers

Based on the currently available data, the risk of infection from contaminated aerosols from heater-cooler devices, in general, is thought to be very low.

If you, or somebody you provide care for, has undergone cardiac surgery in the previous 5 years, be aware of the possible signs and symptoms of Mycobacterium chimaera infection. These may include:

  • fatigue
  • fever
  • pain
  • redness, heat, or pus at the surgical site
  • muscle pain
  • joint pain
  • night sweats
  • weight loss
  • abdominal pain
  • nausea
  • vomiting

If you, or somebody you provide care for, is experiencing any of the signs and symptoms above following cardiac surgery, contact your doctor as soon as possible.

Information for health professionals and facilities

Consistent with the national guidance(link is external) issued by the ACSQHC, the TGA recommends baseline testing, then follow-up testing in accordance with the manufacturer’s instructions. Where information from the manufacturer is not available and the initial sample from the HCD is negative, then follow-up testing should occur at least every three months. This testing cycle should be maintained until further information about this situation becomes available.[1] The manufacturer’s instructions will provide guidance on the type and frequency of testing with common elements being:

  • Two microbiological methods are being recommended by some manufacturers – cultures of heterotropic plate counts (HPC) and mycobacterial cultures.
  • Environmental samples should be submitted to a suitable laboratory identified in consultation with the jurisdictional public health laboratory and tested using validated culture-based methods.
  • Mycobacterial cultures of environmental samples requires specialised expertise, which may not be available in all facilities.
  • Hospital protocols should account for the potential delay in receiving results from mycobacterial cultures, a clear result may take 6-8 weeks or longer.

If there are cases of legionellosis in patients, particularly cardiac surgery patients, then health professionals should consider the heater-cooler device as a possible source. Routine patient testing for legionellosis is not recommended at this time.

Addressing Mycobacterium chimaera infections

Reported infections overseas include surgical site infection, endocarditis, prosthetic valve infection, para-valvular abscess, graft infection and myocarditis. While initial case reports described mostly fatal infections, early recognition of Mycobacterium chimaera as the cause appears to result in better patient outcomes. Based on the available data, the case fatality rate is about 50%.

Some patients have presented with non-cardiac disease: granulomas, osteoarthritis, cholestatic hepatitis, nephritis, splenomegaly, or ocular disease.

Patients undergoing heart valve surgery, particularly with prosthetic implants, are considered to be at highest risk.

Based on the currently available data, the risk of infection from contaminated aerosols from heater-cooler devices, in general, is thought to be very low.

Heater-cooler devices are important in patient care and, in appropriately selected patients, the benefits of temperature control necessary during open chest cardiothoracic procedures outweigh the risk of infection transmission associated with using these devices.

Stratified risk mitigation for Stӧckert 3T Heater-Cooler System (3T) devices

Risk mitigation advice for Stӧckert 3T Heater-Cooler System (3T) devices manufactured before September 2014:

  • Consider transitioning away from reliance on and the use of these devices (regardless of contamination status) for open-chest cardiac surgery until the manufacturer has implemented strategies for these devices to mitigate the risks of patient infection.
    • Use of these devices should be limited to emergent and/or life-threatening situations if no other heater cooler devices are available.
    • Follow the recommendations for all heater-cooler units (detailed below) to help mitigate the risks of patient infection.
    • Be aware that testing of heater-cooler devices to identify units contaminated with Mycobacterium chimaera presents technical challenges related to sample collection, the long culture time, and the possibility of false negative tests.

Risk mitigation for Stӧckert 3T Heater-Cooler System (3T) devices manufactured after Sep 2014:

  • Follow the recommendations for all heater-cooler units (detailed below) to help mitigate the risks of patient infection.

Risk mitigation for all heater-cooler units

  • Strictly adhere to the cleaning and disinfection instructions provided in the manufacturer’s device labelling. Ensure you have the most current version of the manufacturers’ Instructions for Use readily available to promote adherence.
  • Do not use tap water to rinse, fill, refill or top-off water tanks since this may introduce non-tuberculous mycobacterium (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 patient cooling during surgical procedures 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 sterile water created through reverse osmosis is not recommended because it may promote corrosion of the metal components of the system.
  • Direct the heater-cooler’s vent exhaust away from the surgical field to mitigate the risk of aerosolising heater-cooler tank water into the sterile field and exposing the patient.
  • Establish regular cleaning, disinfection and maintenance schedules for heater-cooler devices according to the manufacturers’ instructions to minimise the risk of bacterial growth and subsequent patient infection.
  • Develop and follow a comprehensive quality control program for maintenance, cleaning, and disinfection of heater-cooler devices. Your program may include written procedures for monitoring adherence to the program and documenting set up, cleaning, and disinfection processes before and after use.
  • Regularly check for and immediately remove from service heater-cooler devices and accessories that show discoloration of internal surfaces or cloudiness in the fluid lines/circuits, which may indicate bacterial growth.
  • Consult your hospital infection control officials to perform the appropriate follow up measures and report events of device contamination to the manufacturer and to the TGA.
  • Consider performing environmental (water) sampling of the water supply and monitoring if heater-cooler contamination is suspected. Environmental monitoring requires specialised expertise and equipment to collect and process samples, which may not be feasible in all facilities.
  • Submit a report to the manufacturer and to the TGA, if you suspect heater-cooler devices have been associated with patient infections.

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.

Screening asymptomatic patients for NTM is currently not indicated. At this stage, the TGA recommends liaising with the medical director of the health facility and state/territory public health units to determine the most appropriate protocol in your jurisdiction.

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