Heater-cooler devices are often necessary for use during surgeries to warm or cool patients as part of their care. They are especially important tools for surgeries involving the heart, lungs, esophagus, and other chest organs (cardiothoracic surgeries). Heater-cooler devices, as shown below in Figure 11, include tanks that provide temperature-controlled water to external heat exchangers or to warming/cooling blankets through closed water circuits.
Figure 1: Schematic representation of heater–cooler circuits tested for transmission of Mycobacterium chimaera during cardiac surgery despite an ultraclean air ventilation system. Blue arrows indicate cold water flow, and red arrows indicate hot water flow and patient blood flow.
As indicated above in Figure 1, the:
- Blue arrows identify the cardioplegia circuit and shows cardioplegia solution entering the “heart lung machine.” Cardioplegia is used to stop the heart during surgery.
- Rectangles with zigzag lines are heat exchange coils. They separate heater-cooler fluid flow from patient fluid or blood flow.
- Red arrows identify the patient blood circuit and shows hot water flow and patient blood flow.
Additionally, the water in the heater-cooler device is isolated from the patient, cardioplegia solution and blood circuits.
Heater-cooler devices are Class II devices that can be cleared under one of the following cardiovascular classification regulations:
- 870.4250 Cardiopulmonary Bypass (CPB) Temperature Controller
- 870.5900 Thermal Regulating System
The CPB Temperature Controller is intended to supply temperature-controlled water to heat exchangers associated with devices (e.g., oxygenator) intended to keep circulating blood and organs at a specific temperature best suited to the type of surgery being performed. Thermal Regulating Systems are generally cleared for use with warming/cooling blankets. Although heater-cooler devices fall under the cardiovascular classification regulations, they may be used during a variety of medical procedures.
On October 15, 2015, the FDA issued Nontuberculous Mycobacterium Infections Associated with Heater-Cooler Devices – Safety Communication to heighten awareness about infections associated with heater-cooler devices and steps health care providers and health care facilities can take to mitigate risks to patients. This website contains information for patients, the FDA’s recommendations for health care providers and health facilities that use these devices and steps the FDA is taking to help minimize the risk of infections associated with these devices.
The FDA is holding an Advisory Committee Meeting on June 2-3, 2016 to seek expert scientific and clinical opinion related to heater-cooler device contamination, associated patient infection, and potential mitigation strategies. The Advisory Committee’s opinions on these issues will assist the FDA in providing recommendations to minimize patient exposure to infection.
1 Sommerstein R, Rüegg C, Kohler P, Bloemberg G, Kuster SP, Sax H. Transmission of Mycobacterium chimaera from heater–cooler units during cardiac surgery despite an ultraclean air ventilation system. Emerg Infect Dis. 2016 Jun http://wwwnc.cdc.gov/eid/article/22/6/16-0045_article