Heater cooler device infections are potential complications of open heart surgeries that use certain equipment contaminated with mycobacterium.

Symptoms of mycobacterium infection in a surgical wound can take years to become evident because the bacteria is extremely slow growing.

Once the mycobacterium infection takes hold, symptoms may include:

• Redness, warmth or pus at the site of the surgical incision
• Fatigue
• Fever
• Pain
• Muscle or joint pain
• Night sweats
• Unexplained weight loss
• Abdominal pain
• Nausea and/or vomiting

Many times, if the patient does not have pus around the incision, the patient won’t realize the infection originated with open heart surgery.

Investigators found that heater cooler medical devices called the Stockert 3T made by LivaNova in Europe had been contaminated with a specific nontuberculosis mycobacterium known as M. chimaera. The Mycobacterium chimaera (M. chimaera) bacteria occurs naturally in soil and water, and no one has been able to determine how the contaminant made its way into the Stockert 3T heater coolers.

Interestingly, the water in the heater-cooler unit never touches the human body. The water goes through tubes to help regulate body temperature during the open heart surgery. Researchers determined that M. chimaera was found in water supply installations.

When the Stockert 3T heater cooler produces water vapor as a byproduct, the bacteria may become airborne. The vapor may enter the air of the operating room and can settle into the open chest cavity, where the bacteria can fester after the patient’s wound is closed.

Researchers found that patients could live 1.5 to 3.6 years post-surgery before they began experiencing symptoms of infection. The M. chimaera bacteria can be difficult to treat. Some patients may need to take antimicrobial agents for up to 18 months.

CDC Warns of Heater Cooler Device Infections

The Centers for Disease Control and Prevention issued a warning in 2016 regarding the risk of heater cooler device infections during open heart surgery.

The CDC advised any patient who experienced night sweats, muscle aches, weight loss, fatigue or unexplained fever to contact a medical provider immediately if they had received open heart surgery in the past.

The CDC says that of the more than 250,000 heart bypass procedures performed in the U.S. each year, about 60 percent use the Stockert 3T heater cooler devices associated with the M. chimaera contaminant. Unfortunately, no test is available to determine whether a patient has been exposed to the bacteria.

Any patient fighting an infection from the surgical wound can have a sample taken and sent to a laboratory for a culture to determine the type of bacteria present. Because M. chimaera grows so slowly, such a culture can take up to two months to rule out the specific mycobacterium.

“It’s important for clinicians and their patients to be aware of this risk so that patients can be evaluated and treated quickly,” said Michael Bell, M.D., deputy director of CDC’s Division of Healthcare Quality Promotion in a press release regarding the Stocker 3T heater coolers. “Hospitals should check to see which type of heater-coolers are in use, ensure that they’re maintained according to the latest manufacturer instructions, and alert affected patients and the clinicians who care for them.”