Heater-Cooler Devices and NTM Infections

In late 2016, a Centers for Disease Control (CDC) Health Advisory and Food & Drug Administration (FDA) Safety Communication announced that the Stöckert 3T heater/cooler devices by LivaNova PLC (formerly the Sorin Group) may have been contaminated with Mycobacterium chimaera (M.Chimaera), a rare type of nontuberculous mycobacterium (NTM), during manufacturing.

Keck Medical Center of USC has been monitoring CDC recommendations since the initial recognition of some infections associated with the devices.

  • We have not identified any patient who has developed this infection among the nearly 2,000 patients (since January 1, 2012 to December 5, 2016) at Keck Medical Center of USC who had surgery potentially using the Sorin Stöckert devices.
  • We no longer use the Sorin Stöckert 3T heater-cooler devices. We replaced them on November 21, 2016 with different machines not associated with NTM.
  • If you believe you had a procedure utilizing a cardiopulmonary bypass machine or heart-lung machine between January 1, 2012 and ­­­­November 21, 2016 and have symptoms including night sweats, muscle aches, weight loss, unexplained fever or drainage or redness of surgical wound, please call ­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­(323) 442-9429­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­. Although the likelihood of having contracted NTM is low, we encourage you to address any possible risk by promptly following up if you fall into the category of patients described in the preceding sentence.
  • If you need further guidance, please contact your primary care physician.
  • The CDC website has more information.

Frequently Asked Questions From the CDC:

Q. How were the Stöckert 3T heater/cooler devices used during surgery?

A. Heater-cooler devices are used during cardiothoracic surgeries to warm or cool a patient in order to optimize medical care and improve 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 a small possibility that the contaminated water could have entered other parts of the device and aerosolized, transmitting bacteria through the air and through the device’s exhaust vent into the environment and to a patient.

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Q. What is the risk of infection?

A. Overall, the risk is thought to be very low. In hospitals where at least one infection has been identified, the risk of infection was between about 1 in 100 and 1 in 1,000 patients. Initial information suggests that patients may be at higher risk if they received a heart valve, graft, left ventricular assist device (LVAD) or any other prosthetic product/material or had a heart transplant.

Q. How long does it usually take for these infections to show up?

A. NTM are slow-growing bacteria and infections may take months to develop. Cases associated with this device have been diagnosed within months and up to several years after an open-heart surgery involving heater-cooler unit exposure.

Q. Can a person who develops one of these NTM infections spread it to others, such as family members?

A. No, the bacteria cannot be spread to others from an infected patient. Also, it is important to keep in mind that NTM is common in soil and water but rarely makes healthy people sick.

Q. Should everyone who was exposed to these devices during open-heart surgery receive antibiotics just in case?

A. The risk that patients will develop an infection following exposure to a contaminated heater-cooler unit is very low. There is also no evidence that giving antibiotics just prior or during surgery with a potentially contaminated heater-cooler device will prevent infection. Although antibiotics can be life-saving drugs, there is no antibiotic treatment available to ward off this specific infection, and antibiotics are also not without risk themselves. Antibiotics put patients at risk for allergic reactions and a potentially deadly diarrheal infection caused by the bacteria Clostridium difficile. Antibiotic use is also a key driver of antibiotic resistance, which can put patients at risk for antibiotic-resistant infections later.

Q. How long does it take to find out if an infection is being caused by NTM?

A. M. chimaera is a slow-growing species of NTM that can take eight weeks and sometimes longer to grow and allow final identification.

Q. Why are these infections dangerous?

A. Symptoms of infection can take months to develop and are often general and nonspecific. As a result, diagnosis of these infections can be missed or delayed, sometimes for years, making these infections more difficult to treat. Clinicians may not immediately consider an NTM diagnosis. Delayed diagnosis can result in more widespread disease in a patient. This, combined with underlying health problems such as heart disease can make these infections difficult to treat.

Q. How do you think the devices got contaminated?

A. NTM is common in water and soil. Recent CDC findings are consistent with previous reports suggesting that the heater-cooler units were contaminated during production. Testing conducted by the manufacturer in August of 2014 found M. chimaera contamination on the production line and water supply at the 3T manufacturing facility.

Q. Have these devices ever been recalled?

A. In 2015, the manufacturer recalled the instructions for use, but not the device itself. Information provided by the manufacturer reminded users that while water from the device itself is not intended to contact the patient directly, under certain circumstances, due to fluid leakage and/or aerosolization, NTM could reach a patient’s surgical site. Heater-cooler devices are critical for life-saving surgery.

What clinicians need to know:

  • Clinicians should maintain a high index of suspicion for NTM infection in patients who have undergone cardiopulmonary bypass (especially within Cardiac Surgery, General Thoracic Surgery or Vascular Surgery) over the past 5 years, particularly those who have received valves or other implanted devices.
  • A wide range of clinical presentations has been described in patients with NTM infection after cardiopulmonary bypass, including sternal wound drainage or redness, bacteremia/endocarditis and disseminated infection. NTM infection should be suspected in patients who have persistent unexplained fever, fatigue, night sweats, weight loss, or muscle aches after undergoing cardiac surgery.
  • NTM can be detected only with special cultures for acid-fast bacilli (AFB). AFB cultures should be performed on tissue samples obtained during operative debridement procedures for sternal wound infection or other cardiac or graft infections (note that AFB cultures cannot be performed on swab samples). For patients who present with persistent fever of unclear etiology after cardiac surgery, AFB blood cultures and imaging to evaluate for disseminated infection should be considered.

For additional information from The Society of Thoracic Surgeons, click here.