Prone Position Improves End-Expiratory Lung Volumes in COVID-19 Acute Respiratory Distress Syndrome

Overview

Covid-19 associated Acute Respiratory Distress Syndrome (ARDS) may present with profound hypoxemia not fully explained with pulmonary infiltrates. Accordingly, how prone positioning improves oxygenation in these patients is not fully known. The investigators conducted a study among patients with severe Covid-19 ARDS receiving prone position for at least 16 hours. End Expiratory Lung Volume (EELV) was measured with Nitrogen wash-in/wash-out technique before (Supine Position 1- SP1), during (Prone Position - PP) and after (Supine Position 2 - SP2) prone positioning.

After initiation of invasive mechanical ventilation, initial ventilator settings were performed by the attending physician. These settings include titration of best PEEP to promote oxygenation if Spo2 \<92% despite a Fio2 higher than 80% or best compliance that do not jeopardize oxygenation if Fio2 is between 50-80% and Spo2 \>92%. After a period of 30 minutes for stabilisation, the first set of measurements were done in the SP1 position. Afterwards, the patient was turned to prone position with the same PEEP (which was unchanged throughout the study period) and measurements were repeated every four hours until the patient was reverted back to SP2. Eventually, there were 7 measurements in total. (SP1, PP0, PP4, PP8, PP12, PP16, SP2). Dead space ventilation and shunt fraction calculations were made based on central venous blood gas measurements and oxygen consumption and carbon dioxide production at the relevant timepoint.

Conditions