Extra Vascular Lung Water and Pulmonary Permeability in Critically Ill Patients With SARS-CoV-2 (COVID-19)

Acute respiratory distress syndrome (ARDS) is a syndromic definition of an acute lung injury with alteration of biomechanics (lower respiratory system compliance) mostly associated with increased lesional edema. Increase in Pulmonary Vascular Permeability Index (PVPI) accompanied with accumulation of excess Extravascular Lung Water (EVLW) is the hallmark of ARDS. In routine clinical practice, the investigators measure the EVLW and PVPI in ARDS patients, as suggested by expert's recommendations, using a transpulmonary thermodilution (TPTD) technique. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a newly recognized illness that has spread rapidly throughout Wuhan (Hubei province) to other provinces in China and around the world. Most critically ill patients with SARS-CoV-2 will present the criteria for the definition of ARDS. However, many of these patients have a particular form of ARDS with severe hypoxemia often associated with near normal respiratory system compliance. This combination is almost never seen in severe ARDS. Thus other mechanisms (including probably vascular mechanisms), that are still poorly described, have to be involved in SARS-CoV-2. EVLW and PVPI have never been assessed in SARS-CoV-2 mechanically ventilated patients. The aim of this study is to evaluate these two parameters in order to best characterize and understand the mechanisms related to SARS-CoV-2. Based on observation of several cases in intensive care units (ICU), the investigators hypothesize that there are following different SARS-CoV-2 patterns: 1. Nearly normal compliance, low lung recruitability, normal EVLW and low PVPI. 2. Low compliance due to increased edema, high lung recruitability, high EVLW and high PVPI.