This essential device used during heart surgery may be actually killing you!

There are various devices that are used in an open-heart surgery. But a recent study has found out that more than a third of heater-cooler devices that are used in the surgery are contaminated with deadly bacteria. 33 percent of 89 heater cooler units assessed between July 2015 and December 2016 have resulted positive for Mycobacterium chimaera. According to the research presented at the 44 th Annual Conference of the Association for Professionals in Infection Control and Epidemiology, it has been found out that this bacterium is associated with fatal infections in open-heart surgery patients. 

Heater cooler units are used to control the temperature of a patient’s blood and organs during the heart bypass surgery. Several warnings have already been issued by the US Food and Drug Administration and the Centres for Disease Control and Prevention that a widely used brand of HCU’s might get contaminated during the manufacturing and put patient’s life at risk. Around 60 per cent of surgery performed in the US use the brand of device associated with these infections. 

John Rihs presented a research in which he talked about the advanced knowledge extent of colonization of M. Chimaera that might be present in these units. He along with his colleagues assessed devices already in use for the presence of non-tuberculous mycobacteria colonization in HCUs before and after decontamination. A total of 653 water samples from 89 units were tested. Samples were received from 23 hospitals in 14 states, the District of Columbia, and Canada. 

Thirty-three of the units tested positive for M. chimaera, while four units were colonized with Legionella. Researchers were surprised at how contaminated the units were, with 97 cultures deemed uninterpretable due to high levels of bacterial and fungal contamination. Multiple other strains of mycobacteria were also detected in many of the units.

“Our results showed M. chimera in 37 percent of units tested and is consistent with previous findings. The extent of contamination from such a rare organism in multiple units from all over the country was surprising,” said Rihs. He firther said, “Some devices remained positive for M. chimera for months, indicating that disinfection can be difficult and routine testing is advisable. Beyond M. chimera, we found other NTM species, Legionella, and fungi, indicating these units are capable of supporting a diverse microbial population”. Heater cooler unit controls temperature with the help of water tanks during surgery through closed circuits. The water present in the device does not come into direct contact with the patient. 

“These results highlight the importance of monitoring the decontamination and maintenance schedules of these devices to minimize the risk of patient harm,” said Linda Greene, APIC president. “Hospitals must follow the cleaning and disinfection instructions provided in the manufacturer’s device labelling, as well as updated communications from the FD and CDC”.

The bacteria are often found in soil and water but is rarely associated with infections. If patients exposed to the bacteria through open-heart surgery can develop general and nonspecific symptoms, they can often take months to recover. As a result, diagnosis of these infections can be missed or delayed, sometimes for years, making these infections more difficult to treat.