Mycobacterium chimaera, a non-tuberculous mycobacterium, was recently identified as causative agent of deep-seated infections in patients who had previously undergone open-chest cardiac surgery. Outbreak investigations suggested an aerosol-borne pathogen transmission originating from water contained in heater-cooler units (HCUs) used during cardiac surgery. Similar thermoregulatory devices are used for extracorporeal membrane oxygenation (ECMO) and M. chimaera might also be detectable in ECMO treatment settings. We performed a prospective microbiological study investigating the occurrence of M. chimaera in water from ECMO systems and in environmental samples, and a retrospective clinical review of possible ECMO-related mycobacterial infections among patients in a pneumological intensive care unit. We detected M. chimaera in 9 of 18 water samples from 10 different thermoregulatory ECMO devices; no mycobacteria were found in the nine room air samples and other environmental samples. Among 118 ECMO patients, 76 had bronchial specimens analysed for mycobacteria and M. chimaera was found in three individuals without signs of mycobacterial infection at the time of sampling. We conclude that M. chimaera can be detected in water samples from ECMO-associated thermoregulatory devices and might potentially pose patients at risk of infection. Further research is warranted to elucidate the clinical significance of M. chimaera in ECMO treatment settings.

Extracorporeal carbon dioxide removal (ECCO2R) is increasingly considered a viable therapeutic approach in the management of hypercapnic lung failure to avoid intubation or to allow lung-protective ventilator settings. This study aimed to analyze efficacy and safety of a minimal-invasive ECCO2R device, the Homburg lung. The Homburg lung is a pump-driven system for veno-venous ECCO2R with ¼″ tubing and a 0.8 m surface oxygenator. Vascular access is usually established via a 19F/21 cm bilumen cannula in the right internal jugular vein. For this work, we screened patient registries from two German centers for patients who underwent ECCO2R with the Homburg lung because of hypercapnic lung failure since 2013. Patients who underwent extracorporeal membrane oxygenation before ECCO2R were excluded. Patients who underwent ECCO2R more than one time were only included once. In total, 24 patients (aged 53.86 ± 12.49 years; 62.5% male) were included in the retrospective data analysis. Ventilatory failure occurred because of chronic obstructive pulmonary disease (50%), cystic fibrosis (16.7%), acute respiratory distress syndrome (12.5%), and other origins (20.8%). The system generated a blood flow of 1.18 ± 0.23 liters per minute (lpm). Sweep gas flow was 3.87 ± 2.97 lpm. Within 4 hours, paCO2 could be reduced significantly from 82.05 ± 15.57 mm Hg to 59.68 ± 12.27 mm Hg, thereby, increasing pH from 7.23 ± 0.10 to 7.36 ± 0.09. Cannulation-associated complications were transient arrhythmia (1/24 patients) and air embolism (1/24). Fatal complications did not occur. In conclusion, the Homburg lung provides effective carbon dioxide removal in hypercapnic lung failure. The cannulation is a safe procedure, with complication rates comparable to those in central venous catheter implantation.

Mycobacterium chimaera is a nontuberculous mycobacterium that was identified as causative agent in a global outbreak of severe infections following open-chest cardiothoracic surgery. Heater-cooler units (HCUs), which were contaminated during the manufacturing process, were elucidated as the origin of this outbreak. Regular surveillance of water-containing HCUs used for cardiac surgery was recommended as one preventive measure. We present data on the occurrence of M. chimaera and other mycobacterial pathogens in different HCUs from one surgical center in Germany over a 42-month period. Water samples and swabs from seven different HCUs were taken between 2015 and 2018, and mycobacteria were detected in 50.6% (78/154) of water samples and 21.1% (4/19) of swabs. M. chimaera accounted for the majority of detected pathogens (77/83 isolates in water samples), but other species such as Mycobacterium gordonae were also found. Despite strict adherence to an intensified, regular disinfection procedure, the majority of HCUs remained positive for mycobacteria until the end of the study. In conclusion, additional measures are needed to reduce the risk of intraoperative transmission of M. chimaera, and our observations underscore the inherent infections risks associated with water-containing medical devices.