Prone Positioning in Coronavirus Disease 2019: Just Do It!*

 

Prone Positioning in Coronavirus Disease 2019: Just Do It!*

by Dembinski, Rolf 

 

Critical Care Medicine: July 2021 - Volume 49 - Issue 7 - p 1186-1188

 

Acute respiratory failure is the most common cause of death in patients with coronavirus disease 2019 (COVID-19) (1). Comparable with non-COVID-19–related acute respiratory distress syndrome (ARDS) formation of consolidated atelectasis with concomitant hypoxemia refractory to conventional mechanical ventilation with high Fio2 has been considered as the most decisive pathophysiologic mechanism (2). Accordingly, widely accepted recommendations for the treatment of ARDS such as prone positioning have been applied for the treatment of COVID-19–related respiratory failure in the absence of specific therapeutic options despite a lack of evidence (3).

In ARDS, prone positioning has been shown to improve gas exchange in several studies (4). The most important underlying mechanism is probably a homogenization of transpulmonary pressures resulting in a recruitment of dorsal atelectatic areas thereby reducing ventilation-perfusion mismatch and intrapulmonary right-to-left shunt. In a landmark study by Guérin et al (5), prone positioning within 36 hours after the onset of mechanical ventilation reduced mortality from 33% to 16% in severe ARDS with a Pao2/Fio2 less than 150 mm Hg. Notably, prone positioning in this so-called Proning Severe ARDS Patients (PROSEVA) trial was conducted in well experienced ARDS centers and performed for at least 16 hours. Since then, early prone positioning for at least 16 hours is regularly recommended as an important therapeutic measure in severe ARDS. Unfortunately, prone positioning is still underused in clinical practice, possibly due to limited expertise and the fear of hemodynamic instability (6). Indeed, only a few contraindications such as cardiogenic shock or unstable spine fractures should be accepted.