Heater-cooler units (HCUs) used in cardiopulmonary bypass and extracorporeal membrane oxygenation (ECMO) can generate infectious aerosols containing Mycobacterium chimaera.
To ascertain if HICO-Variotherm units (Chalice Medical) used in ECMO were colonised with Mycobacterium species and to assess the potential for these units to release a bioaerosol.
Water samples were taken from three ECMO HCUs in the Cardiothoracic Critical Care Unit of the Manchester University NHS Foundation Trust (Wythenshawe Hospital) Air samples were taken whilst patients were undergoing veno-venous ECMO. The presence of mycobacteria (or appropriate marker organism(s) was detected via culture and/or real-time qPCR.
Mycobacterium spp. were detected in water taken from two of the three ECMO units.All three ECMO units were colonised with Ralstonia spp. Aerosolisation from the machines into the environment was not demonstrated.
Aerosolisation (bioaerosols) of infectious particles from the HICO-Variotherm HCU was not demonstrated. However, as an aerosolisation risk remains when ECMO machines are decontaminated, emptied or the circuits broken during use, effective disinfection and ongoing microbiological surveillance of the circulating water is vital.