Some quarter-million open heart surgeries are performed in the U.S. each year. In each of those surgeries, heater-cooler devices are used to help stabilize the patient by keeping his or her blood and organs at a homeostatic temperature.

The heater-cooler devices have tanks where warmed water is stored and circulated. The blood is pumped in close proximity but not in direct contact with the tank or water. This allows for heat exchange and blood-temperature maintenance.

However, a little over half of the heater-cooler devices in hospital use have been linked to infections with potential deadly consequences. The heater-cooler devices in question were developed by LivaNova PLC, formerly known as Sorin Group Deutschland.

M. Chimaera

Stockert 3T heater-cooler devices by LivaNova allegedly became contaminated during the manufacturing process in Germany. The contamination was with a bacterium that is normally present in soil and water and relatively harmless—mycobacterium chimaera.

This bacterium becomes much more problematic, however, when it is aerosolized through the venting system of heater-cooler devices near the sterile field of an operating room during invasive open-chest procedures.

Infections from this bacterium can grow very slowly over one-to-four or more years before causing serious symptoms. The symptoms can easily be mistaken for a severe flu or elude proper diagnosis.

In the fall of 2014, the manufacturing plant in Germany where Stockert 3T heater-cooler devices were made was found to be contaminated with M. chimaera. During retesting a little under a year later, the plant was able to pass inspection.

The U.S. Food and Drug Administration (FDA) says machines made after September 2014 have not been linked to diagnosed infections from the bacterium.

Symptoms of infection by M. chimaera can be varied, but underlying exhaustion, random fevers, and night sweats are common. Other experiences may include significant weight loss without an attributable cause, aches in the major joints and muscles, and pain in the chest region with or without redness, swelling, or pus in the area of the original incision. Anyone with a history of open chest surgery with these symptoms should follow-up with their general or cardiac care physician.

Timeline—Warnings and Interventions

Infections from heater-cooler devices are rare, with the number of conclusive diagnosed cases numbering under 30 according to the Centers for Disease Control (CDC). The FDA claims that a dozen people have succumbed to wrongful death from these infections.

The confirmed cases were discovered in the states of Pennsylvania, Iowa, and Michigan beginning in 2011. Because infection with M. chimaera bacteri is slow-growing, it may not always be diagnosed accurately or attributed to a former open-heart surgery and use of a heater-cooler device. More diagnoses may be forthcoming.

The first warning came from the FDA in October 2015 after they were on the receiving end of several medical device reports indicating a problem. Within a year, the Stockert 3T was identified as problematic and guidelines were issues to help medical professionals prevent further infections.

The first class action lawsuit naming LivaNova the liable party was filed in February 2016. Several individuals have also come forward to hold the company liable for infections coming as an alleged consequence of 3T heater-cooler use.