Mechanical ventilation 13 artificial ventilation 9 human 8 adult 7 male 7 Article 6 COVID-19 6 Humans 6 Ventilation 6 controlled study 6 Respiration, Artificial 5 coronavirus disease 2019 5 female 5 intensive care unit 5 Intensive Care Units 4 SARS-CoV-2 4 major clinical study 4 positive end expiratory pressure ventilation 4 retrospective study 4 Biological organs 3 Lung 3 Retrospective Studies 3 Ventilators, Mechanical 3 aged 3 hospitalization 3 lactate dehydrogenase 3 lung 3 mechanical ventilation 3 mechanical ventilator 3 middle aged 3