A recent studyentitled “Microbial Contamination of Heater/Cooler Units: M Chimaera and Beyond” has shed light on non-tuberculosis mycobacteria (NTM) infections that have been linked with of a common heater-cooler device used in open-heart surgery, reports York Dispatch.

In particular, the authors of this observational study looked at the colonization of these non-tuberculous mycobacteria that are linked with open heart surgery infection by studying them before and after the units were decontaminated.

The study looked at a total of 89 heater cooler units, specifically the Sorin 3T, where 33 of the units test positive for M. chimaera, representing 37% of the units tested. These units came from 23 different hospitals across 14 states, as well as Washington D.C. and Canada.

The study concluded that 50.5% of the heater cooler units (45 units) were contaminated with some kind of non-tuberculosis mycobacterium, and 37% specifically tested positive for M. chimaera. About 15% of the water samples could not be properly read and were deemed uninterpretable. The study author stated that these units were so contaminated with other bacteria, it wasn’t easy to determine if any NTM was present.

For awhile, the use of these heater cooler devices during heart surgery did not raise a red flag for causing an open heart surgery infection because water and the unit does not come into direct contact with the patient. It was later found that the device was potentially spraying bacteria into the air through the aerosolized output of the machine’s exhaust, and this bacteria can deposit into the patient, causing open-heart surgery infection.

At York Hospital in York, Pa., an update indicated that 14 patients were identified with “probable” cases of an open heart surgery infection while another three were deemed “suspect” open heart surgery infection cases. Of those identified, six patients have died and one is currently symptom-free and is not currently being treated.

The FDA and CDC have both notified hospitals of the possibility of open heart surgery infection links to the Sorin 3T cardiac heater cooler units. A recent FDA conference held last year concluded with the agency recommending notification among providers be increased, but cautioned against warning patients at this time.

“Panel recommends provider notification before patient notification. If the facility discovers patient infection, the panel does not recommend notifying all patients. Instead, if one patient is identified with an infection, the panel recommends that an investigation be initiated at the facility where the surgery occurred, and local authority should be informed,” a summary from the meeting read.

The agency recommended against broad patient notification that might be “potentially creating alarm,” but some physicians were concerned about not notifying patients directly. However, the CDC apparently felt that patient notification was a priority. An FDA conference call later in the year apparently advised medical professionals to follow the CDC guidelines and notifying patients.

WellSpan Health, a nonprofit that coordinates care at Pennsylvania-area health facilities, has been instrumental in notifying patients who may have a risk of open heart surgery infection do to the use of contaminated heater cooler devicesat York Hospital. However, York Dispatch states that this has also opened up the healthcare provider to being the target of lawsuits, with 12 lawsuits currently filed.