inclusion criteria: - covid-19-positive subject - horowitz index ≤ 200 - bilateral opacities on frontal chest radiograph, and - requirement for positive pressure ventilation via an endotracheal tube or non-invasive ventilation - no clinical signs of left atrial hypertension detected via echocardiography, or if measured, a pulmonary arterial wedge pressure (paop) less than or equal to 18 mmhg. - subject's age ≥ 18 years

inclusion criteria: - covid-19-positive subject - horowitz index ≤ 200 - bilateral opacities on frontal chest radiograph, and - requirement for positive pressure ventilation via an endotracheal tube or non-invasive ventilation - no clinical signs of left atrial hypertension detected via echocardiography, or if measured, a pulmonary arterial wedge pressure (paop) less than or equal to 18 mmhg. - subject's age ≥ 18 years