In December 2019, a series of unexplained cases of pneumonia in the city of Wuhan in China has come to light. In virologic analyses of samples from the patients' deep respiratory tract, a novel coronavirus was isolated (first named 2019-nCoV, then SARS-CoV-2). The disease spread rapidly in the city of Wuhan in early 2020 and soon beyond. On 30 January 2020, the Director-General of the World Health Organization (WHO) declared the outbreak a public health emergency of international concern, and on 11 March 2020, the World Health Organization declared the virus a pandemic.

In humans, an infection with the virus can cause respiratory tract infections or even very severe pneumonia - these often end fatally, especially in old and pre-diseased patients. Due to the novelty of the virus, the data basis for therapy is very limited. To date, there are no clinical data for an effective specific therapy, nor is there a vaccination against the virus available, so that therapy, especially intensive care treatment for very severe courses, must concentrate only on supportive treatment of lung failure and other complications.

The virus is highly contagious and infection results in a relevant number of deaths. Due to very uncertain data on the spread of the virus in the population, it is difficult to estimate the mortality rate - the case fatality rate is about 4% based on the known case numbers.

In reports on the treatment of the first cases in Wuhan (Hubei Province, China) in January 2020, the need for intensive care treatment is described for about a quarter of the inpatient cases, 10-17% had to be ventilated invasively, and veno-venous extracorporeal membrane oxygenation (vv-ECMO) was necessary in 2-4% of the inpatient cases. Patients requiring ECMO have a high mortality rate in the studies published, so far. Recommendations for initiation of ECMO in COVID-19 are being developed, though under continuous review.

Currently, little is known to guide clinicians in the choice of patients eligible for ECMO in COVID-19, nor about the best time point for initiation of ECMO or the value of established clinical scores for the prediction of the outcome of patients.

The aim of the study is to investigate survival in COVID-19 patients requiring vv-ECMO support. Furthermore, the accuracy of clinical scores, established in intensive care medicine for the prediction of outcome in severely ill patients will be assessed. Finally, time to extubation from ventilation and time to ECMO-explantation will be evaluated. The study design is a single-arm retrospective multi-center registry; therefore, no comparator will be evaluated.