SARS-CoV-2 environmental contamination from hospitalised patients with COVID-19 receiving aerosol-generating procedures.

BACKGROUND: Continuous positive airways pressure (CPAP) and high-flow nasal oxygen (HFNO) are considered 'aerosol-generating procedures' in the treatment of COVID-19. OBJECTIVE: To measure air and surface environmental contamination with SARS-CoV-2 virus when CPAP and HFNO are used, compared with supplemental oxygen, to investigate the potential risks of viral transmission to healthcare workers and patients. METHODS: 30 hospitalised patients with COVID-19 requiring supplemental oxygen, with a fraction of inspired oxygen ≥0.4 to maintain oxygen saturation ≥94%, were prospectively enrolled into an observational environmental sampling study. Participants received either supplemental oxygen, CPAP or HFNO (n=10 in each group). A nasopharyngeal swab, three air and three surface samples were collected from each participant and the clinical environment. Real-time quantitative polymerase chain reaction analyses were performed for viral and human RNA, and positive/suspected-positive samples were cultured for the presence of biologically viable virus. RESULTS: Overall 21/30 (70%) participants tested positive for SARS-CoV-2 RNA in the nasopharynx. In contrast, only 4/90 (4%) and 6/90 (7%) of all air and surface samples tested positive (positive for E and ORF1a) for viral RNA respectively, although there were an additional 10 suspected-positive samples in both air and surfaces samples (positive for E or ORF1a). CPAP/HFNO use or coughing was not associated with significantly more environmental contamination than supplemental oxygen use. Only one nasopharyngeal sample was culture positive. CONCLUSIONS: The use of CPAP and HFNO to treat moderate/severe COVID-19 did not appear to be associated with substantially higher levels of air or surface viral contamination in the immediate care environment, compared with the use of supplemental oxygen.

Incidence of early intra-cranial bleeding and ischaemia in adult veno-arterial extracorporeal membrane oxygenation and extracorporeal cardiopulmonary resuscitation patients: a retrospective analysis of risk factors.

BACKGROUND: Cerebral complications in veno-arterial extracorporeal membrane oxygenation are known to have a strong impact on mortality and morbidity. Aim of this study is to investigate the early incidence, risk factors and in-hospital mortality of intra-cranial ischaemia and haemorrhage in adults undergoing veno-arterial extracorporeal membrane oxygenation treatment. METHODS: This study is a single-centre retrospective analysis on adult patients undergoing veno-arterial extracorporeal membrane oxygenation for different indications. The inclusion criterion included patients with early routine cerebral computed tomography imaging during extracorporeal membrane oxygenation, with no clinical evidence of cerebral pathology prior to cannulation. Cerebral complications were grouped by aetiology and the territories of the brain's supplying arteries. RESULTS: One hundred eighty-seven adult patients with a total of 190 veno-arterial extracorporeal membrane oxygenation treatments were included. A total of 16.3% (n = 31) had evidence of either cerebral ischaemia (11.1%) or haemorrhage (5.8%); one patient suffered from both. Cerebral computed tomography scans were performed early in median on the first day after extracorporeal membrane oxygenation cannulation; in-hospital mortality of intra-cranial ischaemia and haemorrhage was 71.4% and 45.5%, respectively. Associated with an increased risk for ischaemic lesions were cannulation of the ascending aorta, higher age, presence of an autoimmune disease and cardiac surgery prior to veno-arterial extracorporeal membrane oxygenation. An association with haemorrhagic lesions was found for a lower blood PaCO2 at 2 hours, lower blood flow through the extracorporeal membrane oxygenation device at 2 hours, higher international normalized ratio and constantly higher activated partial thromboplastin time values as well as higher mean arterial pressures until haemorrhagic lesions were evident. CONCLUSION: Cerebral complications are frequent in patients on veno-arterial extracorporeal membrane oxygenation and may be clinically silent events. Careful monitoring with routine neuroimaging seems to be the most appropriate diagnostic approach at present. Intra-cranial ischaemia occurs more frequent than haemorrhage and is associated with cannulation of the aorta ascendens.

Ex vivo models for research in extracorporeal membrane oxygenation: a systematic review of the literature.

With ongoing progress of components of extracorporeal membrane oxygenation including improvements of oxygenators, pumps, and coating materials, extracorporeal membrane oxygenation became increasingly accepted in the clinical practice. A suitable testing in an adequate setup is essential for the development of new technical aspects. Relevant tests can be conducted in ex vivo models specifically designed to test certain aspects. Different setups have been used in the past for specific research questions. We conducted a systematic literature review of ex vivo models of extracorporeal membrane oxygenation components. MEDLINE and Embase were searched between January 1996 and October 2017. The inclusion criteria were ex vivo models including features of extracorporeal membrane oxygenation technology. The exclusion criteria were clinical studies, abstracts, studies in which the model of extracorporeal membrane oxygenation has been reported previously, and studies not reporting on extracorporeal membrane oxygenation components. A total of 50 studies reporting on different ex vivo extracorporeal membrane oxygenation models have been identified from the literature search. Models have been grouped according to the specific research question they were designed to test for. The groups are focused on oxygenator performance, pump performance, hemostasis, and pharmacokinetics. Pre-clinical testing including use of ex vivo models is an important step in the development and improvement of extracorporeal membrane oxygenation components and materials. Furthermore, ex vivo models offer valuable insights for clinicians to better understand the consequences of choice of components, setup, and management of an extracorporeal membrane oxygenation circuit in any given condition. There is a need to standardize the reporting of pre-clinical studies in this area and to develop best practice in their design.

Administration of mesenchymal stem cells during ECMO results in a rapid decline in oxygenator performance.

Mesenchymal stem cells (MSCs) have attracted attention as a potential therapy for Acute Respiratory Distress Syndrome (ARDS). At the same time, the use of extracorporeal membrane oxygenation (ECMO) has increased among patients with severe ARDS. To date, early clinical trials of MSCs in ARDS have excluded patients supported by ECMO. Here we provide evidence from an ex-vivo model of ECMO to suggest that the intravascular administration of MSCs during ECMO may adversely impact the function of a membrane oxygenator. The addition of clinical grade MSCs resulted in a reduction of flow through the circuit in comparison to controls (0.6 ±0.35 L min-1vs 4.12 ± 0.03 L min-1, at 240 minutes) and an increase in the transoygenator pressure gradient (101±9 mmHg vs 21±4 mmHg, at 240 minutes). Subsequent immunohistochemistry analysis demonstrated quantities of MSCs highly adherent to membrane oxygenator fibres. This study highlights the potential harm associated with MSC therapy during ECMO and suggests further areas of research required to advance the translation of cell therapy in this population.