Fig. 2From: Effectiveness of an adapted diving mask (Owner mask) for non-invasive ventilation in the COVID-19 pandemic scenario: study protocol for a randomized clinical trialStudy timelines of participants/interventions. * t1, start; t2, 1 h after; t3, 2 h after; t4, 24 h after; t5, 48 h after; tx, after the outcome; PaO2/FiO2, ratio of the partial pressure of oxygen in arterial blood (PaO2) to the inspired oxygen fraction (FiO2); OIT, orotraqueal intubation; ICU, intensive care unit; NIV, non-invasive ventilationBack to article page