Is the Prone Position Helpful During Spontaneous Breathing in Patients With COVID-19?

A substantial proportion of patients with coronavirus disease 19 (COVID-19) develop severe respiratory failure and require mechanical ventilation, most often fulfilling criteria for acute respiratory distress syndrome (ARDS).¹ The characteristics of these patients are heterogeneous, consistent with what is known about ARDS.^1,2 Inflammatory edema leads to varying degrees of lung collapse resulting in ventilation perfusion ratio (V̇/Q̇) mismatching, including a significant shunt fraction. Additionally, lung microthrombi are suspected and result in different levels of dead space and inefficient ventilation.³ In sedated patients, gravitational forces lead to lung atelectasis occurs in the dependent lung regions, and the remaining aerated lung available for gas exchange becomes small. Insufficient hypoxic vasoconstriction, another feature of ARDS that contributes to V̇/Q̇ mismatch, is suggested by the finding of hypoxemia with relatively preserved compliance in some patients.⁴