COVID-19 Critically Ill Patients' Evolution After Medical Transport by Train From Paris Intensive Care Units to West of France Intensive Care Units

Since early 2020, France knows a sanitary crisis with a massive influx of COVID-19 patients admitted in Intensive Care Units (ICU). It led to a saturation of the French health system, especially in some geographic areas such as East of France or Paris region. Therefore, authorities decided to transfer some critically ill patients from these crowded ICUs to less busy regional ICUs. it was done for the first time by medical train transportation. Knowing that the investigators lack experience regarding this type of medical evacuation, regarding the high number of transferred patients, with such a logistic effort, the investigators decided to study this phase of the COVID-19 sanitary crisis in order to draw a feedback. So far, there are no data in the literature regarding this topic.

Inclusion Criteria: * Age \> 18 years * COVID-19 positive patients admitted in Intensive Care Unit between 15/03/2020 and 15/04/2020 * Patients (or legal representative) with no opposition to inclusion in medical research protocol * Regarding case group : Patients transferred from Paris's ICU * Regarding case control group : Patients admitted in ICU with no transfer from Paris Exclusion Criteria: \- \> 18 years under legal protection and patients with liberty restriction