This report is a multicenter, observational, analytical and prospective study.
Patients older than 18 years with a diagnosis of COVID-19 by PCR + and who required invasive VM for more than 12 hours from April 1 to August 30, 2020 were included. Subjects admitted to pediatric ICUs and in the recovery room were excluded. Patients who were readmitted and required a new cycle of MV after having been successfully weaned and released from the hospital were also excluded. All patients with data loss greater than 10% in variables considered clinically relevant were eliminated.
The weaning process from mechanical ventilation in each patient was classified by two strategies:
Definition of critical care medicine consensus conference published (2007) in:
Simple weaning: Patients successfully extubated after the first weaning attempt.
Difficult weaning: Patients who fail the first weaning attempt and require up to three spontaneous breathing trials or up to 7 days from the first spontaneous breathing trial to achieve a successful weaning.
Prolonged weaning: Patients who fail at least three weaning attempts or require more than 7 days after the first spontaneous breathing trial.
Definition of WIND study:
Group 0 ("no weaning"), made up of patients who never experienced any attempt to wean.
Group 1 (short weaning): the first attempt resulted in the completion of the weaning process in 1 day (successful weaning or early death).
Group 2 (difficult weaning): weaning was completed after more than 1 day but less than 1 week after the first attempt (successful weaning or death).
Group 3 (prolonged weaning): weaning is not yet completed 7 days after the first attempt (due to successful weaning or death).
The first attempt at weaning in intubated patients was considered as the performance of a spontaneous breathing trial with or without extubation, or extubation with or without SBT. In tracheostomized patients, the first period of spontaneous breathing (without ventilatory support) of at least 24 hours duration was considered as the first weaning attempt.
Weaning success was considered when death or re-intubation did not occur after extubation within 7 days or until discharge from the ICU (whichever occurs first), whether or not non-invasive ventilatory support was used. In tracheostomized patients, weaning was considered successful upon reaching seven consecutive days of spontaneous ventilation without ventilatory support or discharge from the ICU, whichever occurs first. 
The data were collected by the principal investigator of each center, or by one of the members of the work team designated for the study, preferably between 8:00 am and 11:00 am, recorded on paper sheets and dumped into a database " online "designed in REDCap (Research Electronic Data Capture) with software installed in the Centro del Parque clinic, Buenos Aires, Argentina, guaranteeing the protection and confidentiality of the data in accordance with the Declaration of Helsinki. Data were acquired from the moment of admission to the ICU (once the inclusion criteria and the absence of exclusion criteria had been met) and during the entire follow-up period. All members of the research group provided advice and support through direct telephone contact / e-mail specifically originated for the study.