Methods
An open-label randomized crossover clinical trial was conducted between
January and July 2020. Adults receiving invasive mechanical ventilation for
> 24 hours and < 7 days with hemodynamic, respiratory and neurological
stability were randomly assigned at a 1:1 ratio to the sitting position
followed by passive orthostasis condition or the passive orthostasis
followed by the sitting position condition. The primary outcome was lung
aeration assessed using the lung ultrasound score (score ranges from 0
[better] to 36 [worse]).