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Heater-cooler devices and NTM infections

On October 13, 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.

UMHS has been attentively monitoring CDC recommendations since the initial recognition of infections world-wide.

  • We have identified one patient who has developed this infection among the nearly 7,000 patients at the University of Michigan Health System who had surgery potentially using the Sorin Stöckert devices. 
  • As recommended by the CDC, we are working to alert any adult or pediatric patients who underwent a surgical procedure with cardiopulmonary bypass (CPB), including cardiac surgery, general thoracic surgery, vascular or general surgery from June 2011 to August 2016 about the very small risk of infection with nontuberculous mycobacterium, or NTM.
  • We no longer use the Sorin Stöckert 3T heater-cooler devices. We replaced them in August 2016 with different machines not associated with NTM.
  • If you believe you had a procedure (utilizing cardiopulmonary bypass machine or heart-lung machine) with either a cardiac surgery, general thoracic surgery, vascular or general surgery procedure from June 2011 to August 2016, and have symptoms including night sweats, muscle aches, weight loss, unexplained fever or drainage or redness of surgical wound, please call 855-336-5900 between 8 a.m. – 5 p.m. Monday through Friday.
  • The CDC website has more information.

Frequently asked questions from the CDC:

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 who had prosthetic implants are at higher risk. It is possible that not all of the devices introduced these bacteria into the operating room or exposed patients.

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 so deadly?
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? Why aren’t they being recalled now?
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 adult and pediatric 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. Laboratory abnormalities may include leukopenia and LFT elevation.
  • 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. Bone marrow aspiration may also be useful.

If you have a clinical question pertaining to one of your patients, or if you have a symptomatic patient who requires additional evaluation for potential NTM infection, please call M-LINE at (800) 962-3555 to speak to one of our designated providers who can answer your heater-cooler related questions.

 

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