The warnings had been increasing in their severity since the first infections hit. When the FDA initially noted a link between heater-cooler systems and nontuberculous mycobacterium, or NTM, infections, the agency started with a generalized list of precautions to follow to reduce the risk of those infections. Eight months later, an additional Safety Communication was released. And then, four months after that, the FDA named a specific heater-cooler unit, or HCU, as one of particular concern.
It is now believed that up to 600,000 patients may have undergone cardiothoracic surgery in operating rooms where a Stockert 3T HCU was blowing NTM into the air.
CDC estimates say that for a hospital where an infection has occurred, the risk of any patient suffering an NTM infection is somewhere between 1 in 100 and 1 in 1000.
HCUs are used in cardiothoracic surgeries to regulate a patient’s blood and tissue temperatures. Water is circulated through a closed system via a series of tubes and into a blanket that is draped over the patient. Once the water completes the circuit, it is returned to the unit to be re-cooled or re-heated, and sent back through the system once again.
The water never makes contact with the patient’s body. However, it has been determined that HCUs manufactured during a specific timeframe may have been contaminated during the process. This contamination has resulted in bacterial growth within the unit itself. Then, when the exhaust fan activates, the bacteria can become aerosolized and spread throughout a surgical suite.
Under normal circumstances, this would not pose a threat. NTM is largely harmless to a healthy human. To a patient that is immunocompromised, however, or dealing with the trauma of open heart surgery, any infection whatsoever can prove to be deadly.
NTM infection can take months or years to manifest and patients are advised to familiarize themselves with the symptoms so that if they do occur, they can contact their doctor and surgical team. Those symptoms include night sweats, aches and pains, unexplained weight loss, fatigue, and fever.